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1

Local troposphere augmentation for real-time precise point positioning  

NASA Astrophysics Data System (ADS)

The IGS real-time service (RTS) enables real-time precise point positioning (PPP) at a global scale. A long convergence time however is still a challenging factor. In order to reduce the convergence time, external troposphere corrections could be introduced to remove the troposphere effects on the coordinate solution. This paper proposes the use of a local troposphere model to augment real-time PPP. First, undifferenced observations from a network of multiple stations are processed to estimate the station-based troposphere zenith wet delay (ZWD). A set of local troposphere fitting coefficients are then derived using a proposed optimal fitting model. Finally, the determined troposphere fitting coefficients are broadcast to users to reduce the convergence time in the user solution. A continuous operating reference station (CORS) network is utilized to assess the performance of the proposed approach under quiet and active troposphere conditions. The numerical results show that the overall fitting precisions of the local troposphere model can reach 1.42 and 1.05 cm under the two troposphere conditions. The convergence time of the positioning solutions, especially the height solution, can be greatly reduced using the local troposphere model. The horizontal accuracy of 9.2 cm and the vertical accuracy of 10.1 cm are obtainable under the quiet troposphere condition after 20 min of initialization time, compared to the 14.7 cm horizontal and 21.5 cm vertical accuracies in the conventional troposphere estimation approach. Moreover, the horizontal accuracies of 13.0 cm and the vertical accuracies of 12.4 cm have also been obtained after 20 min under the active troposphere condition.

Shi, Junbo; Xu, Chaoqian; Guo, Jiming; Gao, Yang

2014-12-01

2

Adaptive robust Kalman filtering for precise point positioning  

NASA Astrophysics Data System (ADS)

The optimality of precise point postioning (PPP) solution using a Kalman filter is closely connected to the quality of the a priori information about the process noise and the updated mesurement noise, which are sometimes difficult to obtain. Also, the estimation enviroment in the case of dynamic or kinematic applications is not always fixed but is subject to change. To overcome these problems, an adaptive robust Kalman filtering algorithm, the main feature of which introduces an equivalent covariance matrix to resist the unexpected outliers and an adaptive factor to balance the contribution of observational information and predicted information from the system dynamic model, is applied for PPP processing. The basic models of PPP including the observation model, dynamic model and stochastic model are provided first. Then an adaptive robust Kalmam filter is developed for PPP. Compared with the conventional robust estimator, only the observation with largest standardized residual will be operated by the IGG III function in each iteration to avoid reducing the contribution of the normal observations or even filter divergence. Finally, tests carried out in both static and kinematic modes have confirmed that the adaptive robust Kalman filter outperforms the classic Kalman filter by turning either the equivalent variance matrix or the adaptive factor or both of them. This becomes evident when analyzing the positioning errors in flight tests at the turns due to the target maneuvering and unknown process/measurement noises.

Guo, Fei; Zhang, Xiaohong

2014-10-01

3

Precise Point Positioning Ambiguity Resolution: Are we there yet?  

NASA Astrophysics Data System (ADS)

Precise point positioning (PPP) has become a powerful tool for the analysis of Global Positioning System (GPS) measurements in many geoscientific applications. By using the un-differenced ionosphere-free linear combination of the carrier phase observations together with precise satellite and Earth rotation products, sub-centimeter accuracies can be achieved when observing over 24 hours. One limiting factor for PPP, especially in obtaining similar accuracies over shorter observation time spans, was the inability in resolving the carrier phase integer ambiguities, when using data from a single station only, due to the presence of receiver- and satellite-dependent uncalibrated hardware delays (UHD). These offsets originate in the frequency oscillators and it is usually assumed that they are absorbed by the ambiguities in PPP data processing. However, recent studies show that if these UHD can be determined accurately in advance within a reference network, then PPP ambiguity resolution at a single station becomes possible. Similarly to Ge et al. (2007), we determine wide-lane and narrow-lane UHD by averaging the fractional parts of all involved single-difference (between satellites) wide-lane and narrow-lane ambiguity estimates. We then apply these UHD products as ambiguity corrections to recover the integer property of the single-difference wide-lane and narrow-lane ambiguities during PPP. A refinement to the approach by Ge et al. (2007) benefits from the increased stability of the narrow-lane UHD computed from a regional rather than a global reference network. This allows the use of only one set of narrow-lane UHD estimates between a pair of satellites within each continuous tracking period of that pair by the regional network, as opposed to re-computing them at regular (for example 15 minute) intervals. Although this refinement may come with the restriction to a regional scale, the number of UHD parameters to be estimated is significantly reduced, making our approach also applicable to real-time applications if the required satellite orbit and clock, UHD, and Earth rotation products are disseminated in real-time. In this presentation we will show results obtained from our new strategy. In particular, we present statistics of daily and sub-daily PPP solutions with ambiguities resolved, investigate the extent to which our approach is useful in respect of the regionally-estimated UHD and apply the technique to investigate ocean loading deformations associated with a storm surge in the North Sea.

Teferle, F. N.; Geng, J.; Meng, X.; Dodson, A. H.; Ge, M.; Shi, C.; Liu, J.

2009-04-01

4

Analysis of Current Position Determination Accuracy in Natural Resources Canada Precise Point Positioning Service  

NASA Astrophysics Data System (ADS)

Precise Point Positioning (PPP) is a technique used to determine highprecision position with a single GNSS receiver. Unlike DGPS or RTK, satellite observations conducted by the PPP technique are not differentiated, therefore they require that parameter models should be used in data processing, such as satellite clock and orbit corrections. Apart from explaining the theory of the PPP technique, this paper describes the available web-based online services used in the post-processing of observation results. The results obtained in the post-processing of satellite observations at three points, with different characteristics of environment conditions, using the CSRS-PPP service, will be presented as the results of the experiment. This study examines the effect of the duration of the measurement session on the results and compares the results obtained by working out observations made by the GPS system and the combined observations from GPS and GLONASS. It also presents the analysis of the position determination accuracy using one and two measurement frequencies

Krzan, Grzegorz; Dawidowicz, Karol; Krzysztof, ?wia?ek

2013-09-01

5

Precise Point Positioning for the Efficient and Robust Analysis of GPS Data from Large Networks  

NASA Technical Reports Server (NTRS)

Networks of dozens to hundreds of permanently operating precision Global Positioning System (GPS) receivers are emerging at spatial scales that range from 10(exp 0) to 10(exp 3) km. To keep the computational burden associated with the analysis of such data economically feasible, one approach is to first determine precise GPS satellite positions and clock corrections from a globally distributed network of GPS receivers. Their, data from the local network are analyzed by estimating receiver- specific parameters with receiver-specific data satellite parameters are held fixed at their values determined in the global solution. This "precise point positioning" allows analysis of data from hundreds to thousands of sites every (lay with 40-Mflop computers, with results comparable in quality to the simultaneous analysis of all data. The reference frames for the global and network solutions can be free of distortion imposed by erroneous fiducial constraints on any sites.

Zumberge, J. F.; Heflin, M. B.; Jefferson, D. C.; Watkins, M. M.; Webb, F. H.

1997-01-01

6

Precise Point Positioning for the Efficient and Robust Analysis of GPS Data From Large Networks  

NASA Technical Reports Server (NTRS)

Networks of dozens to hundreds of permanently operating precision Global Positioning System (GPS) receivers are emerging at spatial scales that range from 10(exp 0) to 10(exp 3) km. To keep the computational burden associated with the analysis of such data economically feasible, one approach is to first determine precise GPS satellite positions and clock corrections from a globally distributed network of GPS receivers. Then, data from the local network are analyzed by estimating receiver specific parameters with receiver-specific data; satellite parameters are held fixed at their values determined in the global solution. This "precise point positioning" allows analysis of data from hundreds to thousands of sites every day with 40 Mflop computers, with results comparable in quality to the simultaneous analysis of all data. The reference frames for the global and network solutions can be free of distortion imposed by erroneous fiducial constraints on any sites.

Zumberge, J. F.; Heflin, M. B.; Jefferson, D. C.; Watkins, M. M.; Webb, F. H.

1997-01-01

7

Precise point positioning with the BeiDou navigation satellite system.  

PubMed

By the end of 2012, China had launched 16 BeiDou-2 navigation satellites that include six GEOs, five IGSOs and five MEOs. This has provided initial navigation and precise pointing services ability in the Asia-Pacific regions. In order to assess the navigation and positioning performance of the BeiDou-2 system, Wuhan University has built up a network of BeiDou Experimental Tracking Stations (BETS) around the World. The Position and Navigation Data Analyst (PANDA) software was modified to determine the orbits of BeiDou satellites and provide precise orbit and satellite clock bias products from the BeiDou satellite system for user applications. This article uses the BeiDou/GPS observations of the BeiDou Experimental Tracking Stations to realize the BeiDou and BeiDou/GPS static and kinematic precise point positioning (PPP). The result indicates that the precision of BeiDou static and kinematic PPP reaches centimeter level. The precision of BeiDou/GPS kinematic PPP solutions is improved significantly compared to that of BeiDou-only or GPS-only kinematic PPP solutions. The PPP convergence time also decreases with the use of combined BeiDou/GPS systems. PMID:24406856

Li, Min; Qu, Lizhong; Zhao, Qile; Guo, Jing; Su, Xing; Li, Xiaotao

2014-01-01

8

Precise Point Positioning with the BeiDou Navigation Satellite System  

PubMed Central

By the end of 2012, China had launched 16 BeiDou-2 navigation satellites that include six GEOs, five IGSOs and five MEOs. This has provided initial navigation and precise pointing services ability in the Asia-Pacific regions. In order to assess the navigation and positioning performance of the BeiDou-2 system, Wuhan University has built up a network of BeiDou Experimental Tracking Stations (BETS) around the World. The Position and Navigation Data Analyst (PANDA) software was modified to determine the orbits of BeiDou satellites and provide precise orbit and satellite clock bias products from the BeiDou satellite system for user applications. This article uses the BeiDou/GPS observations of the BeiDou Experimental Tracking Stations to realize the BeiDou and BeiDou/GPS static and kinematic precise point positioning (PPP). The result indicates that the precision of BeiDou static and kinematic PPP reaches centimeter level. The precision of BeiDou/GPS kinematic PPP solutions is improved significantly compared to that of BeiDou-only or GPS-only kinematic PPP solutions. The PPP convergence time also decreases with the use of combined BeiDou/GPS systems. PMID:24406856

Li, Min; Qu, Lizhong; Zhao, Qile; Guo, Jing; Su, Xing; Li, Xiaotao

2014-01-01

9

Further characterization of the time transfer capabilities of precise point positioning (PPP): the Sliding Batch Procedure.  

PubMed

In recent years, many national timing laboratories have installed geodetic Global Positioning System receivers together with their traditional GPS/GLONASS Common View receivers and Two Way Satellite Time and Frequency Transfer equipment. Many of these geodetic receivers operate continuously within the International GNSS Service (IGS), and their data are regularly processed by IGS Analysis Centers. From its global network of over 350 stations and its Analysis Centers, the IGS generates precise combined GPS ephemeredes and station and satellite clock time series referred to the IGS Time Scale. A processing method called Precise Point Positioning (PPP) is in use in the geodetic community allowing precise recovery of GPS antenna position, clock phase, and atmospheric delays by taking advantage of these IGS precise products. Previous assessments, carried out at Istituto Nazionale di Ricerca Metrologica (INRiM; formerly IEN) with a PPP implementation developed at Natural Resources Canada (NRCan), showed PPP clock solutions have better stability over short/medium term than GPS CV and GPS P3 methods and significantly reduce the day-boundary discontinuities when used in multi-day continuous processing, allowing time-limited, campaign-style time-transfer experiments. This paper reports on follow-on work performed at INRiM and NRCan to further characterize and develop the PPP method for time transfer applications, using data from some of the National Metrology Institutes. We develop a processing procedure that takes advantage of the improved stability of the phase-connected multi-day PPP solutions while allowing the generation of continuous clock time series, more applicable to continuous operation/monitoring of timing equipment. PMID:19686979

Guyennon, Nicolas; Cerretto, Giancarlo; Tavella, Patrizia; Lahaye, François

2009-08-01

10

Flight Test Evaluation of Precise Point Positioning Techniques Using Optical Ranging  

NASA Astrophysics Data System (ADS)

This article reports on a flight test for the purpose of validating single-vehicle Global Positioning System (GPS) precise point positioning (PPP) of an aircraft using JPL's Global Navigation Satellite System (GNSS)-Inferred Positioning System (GIPSY) software and postprocessed satellite products. The article provides a comparison of a laser ranging device to GPS position estimates relative to a fixed ground station. The range data derived independently from the laser and GPS techniques agree to an average of 6.6 cm (RMS). The flight test was conducted on a Cessna aircraft circling the laser ranging device installed at Table Mountain in Wrightwood, California, at a range of approximately 6 km while the aircraft flew at an altitude of about 4.3 km. An error budget is presented based on the GPS, laser, meteorology, and inertial sensors employed. The survey of the locations of the instruments and associated error is presented. The range error of 6.6 cm RMS is consistent with the error in the instruments and survey.

Williamson, W.; Haines, B.; Wilson, K.; Kovalik, J.; Wright, M.; Meyer, R.; Bar-Sever, Y.

2012-11-01

11

Integrity monitoring in real-time precise point positioning in the presence of ionospheric disturbances  

NASA Astrophysics Data System (ADS)

Ionospheric disturbances are characterized as fast and random variability in the ionosphere. Those phenomena are difficult to predict, detect and model. Occurrence of some strong ionospheric disturbances can cause, inter alia degradation and interruption of GNSS signals. Therefore they are especially harmful for real-time applications, as for example Precise Point Positioning (PPP) in real time, where one of the most important requirements is to ensure the high level of reliability. In such applications verification and confirmation of a high trust degree towards the estimated coordinates is a very critical issue. In one of the previous papers (K. Wezka, 2012 -Identification of system performance parameters and their usability) two sets of parameters have been proposed for enhance reliability of the PPP. The first one for data quality control (QC) of the raw GNSS observations and the second one for examination of the quality, robustness and performance of various processing approaches (strategies). To the second group the following parameters has been proposed: accuracy, precision, availability, integrity and convergence time. In consideration of perturbation of GNSS signal resulting from sudden ionospheric disturbances, one of the most important demands is effective autonomous integrity monitoring. The poster presents first preliminary results of the applicability of the proposed parameters in order to ensure the high level of reliability/integrity of GNSS observations and positioning results under the presence of strong ionospheric anomalies. The data-set from continuously operated GNSS station located at high latitude, where ionospheric disturbances occur more frequently, were used for the analysis. Various selected Receiver Autonomous Integrity Monitoring (RAIM) approaches for quality control of the GNSS observables are applied to the data sets recorded under different (low/quite and high) ionospheric activities. Based on those analyses the usability of the proposed parameters is verified.

Wezka, K.; Galas, R.

2013-12-01

12

Real-time retrieval of precipitable water vapor from GPS precise point positioning  

NASA Astrophysics Data System (ADS)

of precipitable water vapor (PWV) using the Global Positioning System (GPS) has been intensively investigated in the past 2 decades. However, it still remains a challenging task at a high temporal resolution and in the real-time mode. In this study the accuracy of real-time zenith total delay (ZTD) and PWV using the GPS precise point positioning (PPP) technique is investigated. GPS observations in a 1 month period from 20 globally distributed stations are selected for testing. The derived real-time ZTDs at most stations agree well with the tropospheric products from the International Global Navigation Satellite Systems Service, and the root-mean-square errors (RMSEs) are <13 mm, which meet the threshold value of 15 mm if ZTDs are input to numerical weather prediction models. The RMSE of the retrieved PWVs in comparison with the radiosonde-derived values are ?3 mm, which is the threshold RMSE of PWVs as inputs to weather nowcasting. The theoretical accuracy of PWVs is also discussed, and 3 mm quality of PWVs is proved achievable in different temperature and humidity conditions. This implies that the real-time GPS PPP technique can be complementary to current atmospheric sounding systems, especially for nowcasting of extreme weather due to its real-time, all-day, and all-weather capabilities and high temporal resolutions.

Yuan, Yubin; Zhang, Kefei; Rohm, Witold; Choy, Suelynn; Norman, Robert; Wang, Chuan-Sheng

2014-08-01

13

Combined GPS/GLONASS Precise Point Positioning with Fixed GPS Ambiguities  

PubMed Central

Precise point positioning (PPP) technology is mostly implemented with an ambiguity-float solution. Its performance may be further improved by performing ambiguity-fixed resolution. Currently, the PPP integer ambiguity resolutions (IARs) are mainly based on GPS-only measurements. The integration of GPS and GLONASS can speed up the convergence and increase the accuracy of float ambiguity estimates, which contributes to enhancing the success rate and reliability of fixing ambiguities. This paper presents an approach of combined GPS/GLONASS PPP with fixed GPS ambiguities (GGPPP-FGA) in which GPS ambiguities are fixed into integers, while all GLONASS ambiguities are kept as float values. An improved minimum constellation method (MCM) is proposed to enhance the efficiency of GPS ambiguity fixing. Datasets from 20 globally distributed stations on two consecutive days are employed to investigate the performance of the GGPPP-FGA, including the positioning accuracy, convergence time and the time to first fix (TTFF). All datasets are processed for a time span of three hours in three scenarios, i.e., the GPS ambiguity-float solution, the GPS ambiguity-fixed resolution and the GGPPP-FGA resolution. The results indicate that the performance of the GPS ambiguity-fixed resolutions is significantly better than that of the GPS ambiguity-float solutions. In addition, the GGPPP-FGA improves the positioning accuracy by 38%, 25% and 44% and reduces the convergence time by 36%, 36% and 29% in the east, north and up coordinate components over the GPS-only ambiguity-fixed resolutions, respectively. Moreover, the TTFF is reduced by 27% after adding GLONASS observations. Wilcoxon rank sum tests and chi-square two-sample tests are made to examine the significance of the improvement on the positioning accuracy, convergence time and TTFF. PMID:25237901

Pan, Lin; Cai, Changsheng; Santerre, Rock; Zhu, Jianjun

2014-01-01

14

Combined GPS/GLONASS Precise Point Positioning with Fixed GPS Ambiguities.  

PubMed

Precise point positioning (PPP) technology is mostly implemented with an ambiguity-float solution. Its performance may be further improved by performing ambiguity-fixed resolution. Currently, the PPP integer ambiguity resolutions (IARs) are mainly based on GPS-only measurements. The integration of GPS and GLONASS can speed up the convergence and increase the accuracy of float ambiguity estimates, which contributes to enhancing the success rate and reliability of fixing ambiguities. This paper presents an approach of combined GPS/GLONASS PPP with fixed GPS ambiguities (GGPPP-FGA) in which GPS ambiguities are fixed into integers, while all GLONASS ambiguities are kept as float values. An improved minimum constellation method (MCM) is proposed to enhance the efficiency of GPS ambiguity fixing. Datasets from 20 globally distributed stations on two consecutive days are employed to investigate the performance of the GGPPP-FGA, including the positioning accuracy, convergence time and the time to first fix (TTFF). All datasets are processed for a time span of three hours in three scenarios, i.e., the GPS ambiguity-float solution, the GPS ambiguity-fixed resolution and the GGPPP-FGA resolution. The results indicate that the performance of the GPS ambiguity-fixed resolutions is significantly better than that of the GPS ambiguity-float solutions. In addition, the GGPPP-FGA improves the positioning accuracy by 38%, 25% and 44% and reduces the convergence time by 36%, 36% and 29% in the east, north and up coordinate components over the GPS-only ambiguity-fixed resolutions, respectively. Moreover, the TTFF is reduced by 27% after adding GLONASS observations. Wilcoxon rank sum tests and chi-square two-sample tests are made to examine the significance of the improvement on the positioning accuracy, convergence time and TTFF. PMID:25237901

Pan, Lin; Cai, Changsheng; Santerre, Rock; Zhu, Jianjun

2014-01-01

15

Predicting atmospheric delays for rapid ambiguity resolution in precise point positioning  

NASA Astrophysics Data System (ADS)

Integer ambiguity resolution in precise point positioning (PPP) can shorten the initialization and re-initialization time, and ambiguity-fixed PPP solutions are also more reliable and accurate than ambiguity-float PPP solutions. However, signal interruptions are unavoidable in practical applications, particularly while operating in urban areas. Such signal interruptions can cause discontinuity of carrier phase arc, which introduces new integer ambiguities. Usually it will take approximately 15 min of continuous tracking to a reasonable number of satellites to fix new integer ambiguities. In many applications, it is impractical for a PPP user to wait for such a long time for the re-initialization. In this paper, a method for rapid ambiguity fixing in PPP is developed to avoid such a long re-initialization time. Firstly, the atmospheric delays were estimated epoch by epoch from ambiguity-fixed PPP solutions before the data gap or cycle slip occurs. A random walk procedure is then applied to predict the atmospheric delays accurately over a short time span. The predicted atmospheric delays then can be used to correct the observations which suffer from signal interruptions. Finally, the new ambiguities can be fixed with a distinct WL-LX-L3 (here LX denotes either of L1, L2) cascade ambiguity resolution strategy. Comprehensive experiments have demonstrated that the proposed method and strategy can fix zero-difference integer ambiguities successfully with only a single-epoch observation immediately after a short data gap. This technique works even when all satellites are interrupted at the same time. The duration of data gap bridged by this technique could be possibly extended if a more precise atmospheric delay prediction is found or on-the-fly (OTF) technology is applied. Based on the proposed method, real-time PPP with integer ambiguity fixing becomes more feasible in practice.

Li, Xingxing; Zhang, Xiaohong; Guo, Fei

2014-09-01

16

Determination of earthquake magnitude using GPS displacement waveforms from real-time precise point positioning  

NASA Astrophysics Data System (ADS)

For earthquake and tsunami early warning and emergency response, earthquake magnitude is the crucial parameter to be determined rapidly and correctly. However, a reliable and rapid measurement of the magnitude of an earthquake is a challenging problem, especially for large earthquakes (M > 8). Here, the magnitude is determined based on the GPS displacement waveform derived from real-time precise point positioning (RTPPP). RTPPP results are evaluated with an accuracy of 1 cm in the horizontal components and 2-3 cm in the vertical components, indicating that the RTPPP is capable of detecting seismic waves with amplitude of 1 cm horizontally and 2-3 cm vertically with a confidence level of 95 per cent. In order to estimate the magnitude, the unique information provided by the GPS displacement waveform is the horizontal peak displacement amplitude. We show that the empirical relation of Gutenberg (1945) between peak displacement and magnitude holds up to nearly magnitude 9.0 when displacements are measured with GPS. We tested the proposed method for three large earthquakes. For the 2010 Mw 7.2 El Mayor-Cucapah earthquake, our method provides a magnitude of M7.18 ± 0.18. For the 2011 Mw 9.0 Tohoku-oki earthquake the estimated magnitude is M8.74 ± 0.06, and for the 2010 Mw 8.8 Maule earthquake the value is M8.7 ± 0.1 after excluding some near-field stations. We, therefore, conclude that depending on the availability of high-rate GPS observations, a robust value of magnitude up to 9.0 for a point source earthquake can be estimated within tens of seconds or a few minutes after an event using a few GPS stations close to the epicentre. The rapid magnitude could be as a pre-requisite for tsunami early warning, fast source inversion and emergency response is feasible.

Fang, Rongxin; Shi, Chuang; Song, Weiwei; Wang, Guangxing; Liu, Jingnan

2014-01-01

17

Assessment of correct fixing rate for precise point positioning ambiguity resolution on a global scale  

NASA Astrophysics Data System (ADS)

Ambiguity resolution (AR) for a single receiver has been a popular topic in Global Positioning System (GPS) recently. Ambiguity-resolution methods for precise point positioning (PPP) have been well documented in recent years, demonstrating that it can improve the accuracy of PPP. However, users are often concerned about the reliability of ambiguity-fixed PPP solution in practical applications. If ambiguities are fixed to wrong integers, large errors would be introduced into position estimates. In this paper, we aim to assess the correct fixing rate (CFR), i.e., number of ambiguities correctly fixing to the total number of ambiguities correctly and incorrectly fixing, for PPP user ambiguity resolution on a global scale. A practical procedure is presented to evaluate the CFR of PPP user ambiguity resolution. GPS data of the first 3 days in each month of 2010 from about 390 IGS stations are used for experiments. Firstly, we use GPS data collected from about 320 IGS stations to estimate global single-differenced (SD) wide-lane and narrow-lane satellite uncalibrated phase delays (UPDs). The quality of UPDs is evaluated. We found that wide-lane UPD estimates have a rather small standard deviation (Std) between 0.003 and 0.004 cycles while most of Std of narrow-lane estimates are from 0.01 to 0.02 cycles. Secondly, many experiments have been conducted to investigate the CFR of integer ambiguity resolution we can achieve under different conditions, including reference station density, observation session length and the ionospheric activity. The results show that the CFR of PPP can exceed 98.0 % with only 1 h of observations for most user stations. No obvious correlation between the CFR and the reference station density is found. Therefore, nearly homogeneous CFR can be achieved in PPP AR for global users. At user end, higher CFR could be achieved with longer observations. The average CFR for 30-min, 1-h, 2-h and 4-h observation is 92.3, 98.2, 99.5 and 99.7 %, respectively. In order to get acceptable CFR, 1 h is a recommended minimum observation time. Furthermore, the CFR of PPP can be affected by diurnal variation and geomagnetic latitude variation in the ionosphere. During one day at the hours when rapid ionospheric variations occur or in low geomagnetic latitude regions where equatorial electron density irregularities are produced relatively frequently, a significant degradation of the CFR is demonstrated.

Zhang, Xiaohong; Li, Pan

2013-06-01

18

Evaluation of High-Precision, Single-Frequency GPS Point Positioning Models  

Microsoft Academic Search

In this paper we evaluate the performance of single- frequency, single-point positioning processors with an emphasis on ionospheric delay handling. A number of least-squares processors with single- frequency code-only and code-and-carrier-phase observables were developed. Processing model hierarchy is based on measurement error handling, starting with a basic code-based navigation solution and progressing to the code-and-carrier-phase model. Measurement error handling includes

Tomas Beran; Sunil B. Bisnath; Richard B. Langley

19

Precision Pointing System Development  

SciTech Connect

The development of precision pointing systems has been underway in Sandia's Electronic Systems Center for over thirty years. Important areas of emphasis are synthetic aperture radars and optical reconnaissance systems. Most applications are in the aerospace arena, with host vehicles including rockets, satellites, and manned and unmanned aircraft. Systems have been used on defense-related missions throughout the world. Presently in development are pointing systems with accuracy goals in the nanoradian regime. Future activity will include efforts to dramatically reduce system size and weight through measures such as the incorporation of advanced materials and MEMS inertial sensors.

BUGOS, ROBERT M.

2003-03-01

20

On the Convergence of Ionospheric Constrained Precise Point Positioning (IC-PPP) Based on Undifferential Uncombined Raw GNSS Observations  

PubMed Central

Precise Point Positioning (PPP) has become a very hot topic in GNSS research and applications. However, it usually takes about several tens of minutes in order to obtain positions with better than 10 cm accuracy. This prevents PPP from being widely used in real-time kinematic positioning services, therefore, a large effort has been made to tackle the convergence problem. One of the recent approaches is the ionospheric delay constrained precise point positioning (IC-PPP) that uses the spatial and temporal characteristics of ionospheric delays and also delays from an a priori model. In this paper, the impact of the quality of ionospheric models on the convergence of IC-PPP is evaluated using the IGS global ionospheric map (GIM) updated every two hours and a regional satellite-specific correction model. Furthermore, the effect of the receiver differential code bias (DCB) is investigated by comparing the convergence time for IC-PPP with and without estimation of the DCB parameter. From the result of processing a large amount of data, on the one hand, the quality of the a priori ionosphere delays plays a very important role in IC-PPP convergence. Generally, regional dense GNSS networks can provide more precise ionosphere delays than GIM and can consequently reduce the convergence time. On the other hand, ignoring the receiver DCB may considerably extend its convergence, and the larger the DCB, the longer the convergence time. Estimating receiver DCB in IC-PPP is a proper way to overcome this problem. Therefore, current IC-PPP should be enhanced by estimating receiver DCB and employing regional satellite-specific ionospheric correction models in order to speed up its convergence for more practical applications. PMID:24253190

Zhang, Hongping; Gao, Zhouzheng; Ge, Maorong; Niu, Xiaoji; Huang, Ling; Tu, Rui; Li, Xingxing

2013-01-01

21

Estimation of precipitable water vapour using kinematic GNSS precise point positioning over an altitude range of 1 km  

NASA Astrophysics Data System (ADS)

The estimation of total precipitable water vapour (PWV) using kinematic GNSS has been investigated since around 2001, aiming to extend the use of static ground-based GNSS, from which PWV estimates are now operationally assimilated into numerical weather prediction models. To date, kinematic GNSS PWV studies suggest a PWV measurement agreement with radiosondes of 2-3 mm, almost commensurate with static GNSS measurement accuracy, but only shipborne experiments have so far been carried out. As a first step towards extending such sea level-based studies to platforms that operate at a range of altitudes, such as airplanes or land based vehicles, the kinematic GNSS estimation of PWV over an exactly repeated trajectory is considered. A data set was collected from a GNSS receiver and antenna mounted on a carriage of the Snowdon Mountain Railway, UK, which continually ascends and descends through 950 m of vertical relief. Static GNSS reference receivers were installed at the top and bottom of the altitude profile, and derived zenith wet delay (ZWD) was interpolated to the altitude of the train to provide reference values together with profile estimates from the 100 m resolution runs of the Met Office's Unified Model. We demonstrate similar GNSS accuracies as obtained from previous shipborne studies, namely a double difference relative kinematic GNSS ZWD accuracy within 14 mm, and a kinematic GNSS precise point positioning ZWD accuracy within 15 mm. The latter is a more typical airborne PWV estimation scenario i.e. without the reliance on ground-based GNSS reference stations. We show that the kinematic GPS-only precise point positioning ZWD estimation is enhanced by also incorporating GLONASS observations.

Webb, S. R.; Penna, N. T.; Clarke, P. J.; Webster, S.; Martin, I.

2013-12-01

22

Rapid earthquake magnitude from real-time GPS precise point positioning for earthquake early warning and emergency response  

NASA Astrophysics Data System (ADS)

For earthquake early warning (EEW) and emergency response, earthquake magnitude is the crucial parameter to be determined rapidly and correctly. However, a reliable and rapid measurement of the magnitude of an earthquake is a challenging problem, especially for large earthquakes (M>8). Here, the magnitude is determined based on the GPS displacement waveform derived from real-time precise point positioning (PPP). The real-time PPP results are evaluated with an accuracy of 1 cm in the horizontal components and 2-3 cm in the vertical components, indicating that the real-time PPP is capable of detecting seismic waves with amplitude of 1cm horizontally and 2-3cm vertically with a confidence level of 95%. In order to estimate the magnitude, the unique information provided by the GPS displacement waveform is the horizontal peak displacement amplitude. We show that the empirical relation of Gutenberg (1945) between peak displacement and magnitude holds up to nearly magnitude 9.0 when displacements are measured with GPS. We tested the proposed method for three large earthquakes. For the 2010 Mw 7.2 El Mayor-Cucapah earthquake, our method provides a magnitude of M7.18±0.18. For the 2011 Mw 9.0 Tohoku-oki earthquake the estimated magnitude is M8.74±0.06, and for the 2010 Mw 8.8 Maule earthquake the value is M8.7±0.1 after excluding some near-field stations. We therefore conclude that depending on the availability of high-rate GPS observations, a robust value of magnitude up to 9.0 for a point source earthquake can be estimated within 10s of seconds or a few minutes after an event using a few GPS stations close to the epicenter. The rapid magnitude could be as a pre-requisite for tsunami early warning, fast source inversion, and emergency response is feasible.

Fang, Rongxin; Shi, Chuang; Song, Weiwei; Wang, Guangxing; Liu, Jingnan

2014-05-01

23

GPS single frequency precise orbit determination of LEO satellites with the cm-level accuracy and comparison with the precise point positioning  

NASA Astrophysics Data System (ADS)

Using single frequency GPS measurements from the CHAMP satellite it was demonstrated before that during the solar maximum the LEO orbit can be determined with an accuracy below 10 cm RMS (1D). The first order ionosphere effect is removed by linear combination of pseudorange and carrier phase measurements using the so-called LP linear combination. The main limitation of this POD approach is the high noise of the pseudorange measurements. By forming the LP linear combination, noise in the pseudorange measurements is reduced by 50%, and by estimating half-cycle phase ambiguities an additional reduction can be expected in all systematic effects (e.g. multipath, group delay variations, etc.). Furthermore, thanks to the high quality GPS measurements from the GRACE mission, it was demonstrated that the orbit of a LEO satellite can be determined using single frequency measurements with an accuracy of 5 cm RMS (1D). This is very close to the cm-level accuracy of the LEO orbits based on dual-frequency carrier phase measurements. Here we show that based on the latest gravity field models short term perturbations can very accurately be modelled in the numerical integration, considerably reducing the number of empirical parameters. This allows to average errors in the pseudorange measurements over a longer period of time and further increase the accuracy of GRACE orbit down to 3 cm RMS (1D) and beyond. However, at this level of accuracy systematic errors in the code to carrier coherence play a crucial role, especially in terms of signal group delay variations of GPS satellite and LEO antenna. Here we demonstrate a novel approach in the code to carrier calibration based on a geometry and ionosphere free linear combination. We show that it is possible to separate the group delay variations of the GPS satellite antenna from the group delay variations of a LEO or a ground antenna. This leads to very accurate mean group delay maps of the GPS satellite antennas. Validation of the code to carrier coherence calibration is carried out with the independent measurements from a high-gain steerable ground antenna. Here we show how code to phase coherence calibration improves LEO orbit determination based on single frequency measurements and compare our results with the ground precise point positioning based on single-frequency GPS measurements. A typical performance curve relating convergence time and accuracy is derived for PPP, as well as POD of the GRACE satellites during the solar minimum and maximum.

Svehla, Drazen; Escobar, Diego A.; Dow, John M.

24

Real-time high-rate co-seismic displacement from ambiguity-fixed precise point positioning: Application to earthquake early warning  

NASA Astrophysics Data System (ADS)

Abstract<p label="1">Nowadays more and more high-rate real-time GPS data become available that provide a great opportunity to contribute to earthquake early warning (EEW) system in terms of capturing regional surface displacements, as an independent information source, useful for promptly estimating the magnitude of large destructive earthquake. In our study, we demonstrate the performance of the real-time ambiguity-fixed <span class="hlt">precise</span> <span class="hlt">point</span> <span class="hlt">positioning</span> (PPP) approach using 5 Hz GPS data collected during El Mayor-Cucapah earthquake (Mw 7.2, 4 April 2010). The PPP-based displacements show to agree with accelerometer-based displacement at centimeter level. The key for successfully obtaining high <span class="hlt">precision</span> displacements is the efficient ambiguity resolution. PPP with ambiguity fixing can result in correct permanent co-seismic offsets and correct recovery of moment magnitude and fault slip inversion at levels comparable to post-processing.</p> <div class="credits"> <p class="dwt_author">Li, Xingxing; Ge, Maorong; Zhang, Xiaohong; Zhang, Yong; Guo, Bofeng; Wang, Rongjiang; Klotz, Jürgen; Wickert, Jens</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">25</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19870020437&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">A reactionless <span class="hlt">precision</span> <span class="hlt">pointing</span> actuator</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The applications, design, control and testing of an actuator that provides the <span class="hlt">precise</span> motion control of a gimbal platform without torquing against the basebody to which it is attached are described. The reactionless actuator described was given the name reactuator.</p> <div class="credits"> <p class="dwt_author">Wiktor, Peter</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">26</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/22048044"> <span id="translatedtitle"><span class="hlt">PRECISION</span> <span class="hlt">POINTING</span> OF IBEX-Lo OBSERVATIONS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Post-launch boresight of the IBEX-Lo instrument on board the Interstellar Boundary Explorer (IBEX) is determined based on IBEX-Lo Star Sensor observations. Accurate information on the boresight of the neutral gas camera is essential for <span class="hlt">precise</span> determination of interstellar gas flow parameters. Utilizing spin-phase information from the spacecraft attitude control system (ACS), <span class="hlt">positions</span> of stars observed by the Star Sensor during two years of IBEX measurements were analyzed and compared with <span class="hlt">positions</span> obtained from a star catalog. No statistically significant differences were observed beyond those expected from the pre-launch uncertainty in the Star Sensor mounting. Based on the star observations and their <span class="hlt">positions</span> in the spacecraft reference system, <span class="hlt">pointing</span> of the IBEX satellite spin axis was determined and compared with the <span class="hlt">pointing</span> obtained from the ACS. Again, no statistically significant deviations were observed. We conclude that no systematic correction for boresight geometry is needed in the analysis of IBEX-Lo observations to determine neutral interstellar gas flow properties. A stack-up of uncertainties in attitude knowledge shows that the instantaneous IBEX-Lo <span class="hlt">pointing</span> is determined to within {approx}0.{sup 0}1 in both spin angle and elevation using either the Star Sensor or the ACS. Further, the Star Sensor can be used to independently determine the spacecraft spin axis. Thus, Star Sensor data can be used reliably to correct the spin phase when the Star Tracker (used by the ACS) is disabled by bright objects in its field of view. The Star Sensor can also determine the spin axis during most orbits and thus provides redundancy for the Star Tracker.</p> <div class="credits"> <p class="dwt_author">Hlond, M.; Bzowski, M. [Space Research Centre of the Polish Academy of Sciences, 18A Bartycka, 00-716 Warsaw (Poland); Moebius, E.; Kucharek, H.; Heirtzler, D.; Schwadron, N. A.; Neill, M. E. O'; Clark, G. [Space Science Center and Department of Physics, University of New Hampshire, Morse Hall, 8 College Road, Durham, NH 03824 (United States); Crew, G. B. [Haystack Observatory, Massachusetts Institute of Technology, Route 40, Westford, MA 01886 (United States); Fuselier, S. [Lockheed Martin, Space Physics Lab, 3251 Hanover Street, Palo Alto, CA 94304 (United States); McComas, D. J., E-mail: mhlond@cbk.waw.pl, E-mail: eberhard.moebius@unh.edu, E-mail: gbc@haystack.mit.edu, E-mail: stephen.a.fuselier@linco.com, E-mail: DMcComas@swri.edu, E-mail: DMcComas@swri.edu [Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228 (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">27</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50584267"> <span id="translatedtitle">Active Thermal Management for <span class="hlt">Precision</span> <span class="hlt">Positioning</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Precision</span> <span class="hlt">positioning</span> systems are inevitably subject to various thermal disturbances including heating from motors, friction between components, and ambient temperature fluctuations. Thermal disturbances cause unwanted thermal expansion and contraction; the resulting distortion of the components in the <span class="hlt">positioning</span> system could lead to degraded <span class="hlt">positioning</span> accuracy. This paper explores the application of estimation and control techniques to address thermally-induced <span class="hlt">positioning</span> error.</p> <div class="credits"> <p class="dwt_author">Rongliang Zhou; Bill Gressick; John T. Wen; Michael Jensen; Joe Frankel; Grey Lerner; Mark Unrath</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">28</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/30214970"> <span id="translatedtitle"><span class="hlt">Precise</span> <span class="hlt">positioning</span> of patients for radiation therapy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A number of immobilization schemes which permit <span class="hlt">precise</span> daily <span class="hlt">positioning</span> of patients for radiation therapy are discussed. Pretreatment and post-treatment radiographs have been taken with the patient in the treatment <span class="hlt">position</span> and analyzed to determine the amount of intratreatment movement. Studies of patients in the supine, seated and decubitus <span class="hlt">positions</span> indicate mean movements of less than 1 mm with a</p> <div class="credits"> <p class="dwt_author">Lynn J. Verhey; Michael Goitein; Patricia McNulty; John E. Munzenrider; Herman D. Suit</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">29</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dspace.mit.edu/handle/1721.1/33905"> <span id="translatedtitle">Rubber bearings for <span class="hlt">precision</span> <span class="hlt">positioning</span> systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">In this thesis we investigate the use of thin rubber sheets or laminates of metal and rubber sheets as bearings in <span class="hlt">precision</span> <span class="hlt">positioning</span> systems. Such bearings have the potential to replace more conventional flexures ...</p> <div class="credits"> <p class="dwt_author">Barton Martinelli, Augusto E</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">30</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19950048809&hterms=precision+pointing&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">EOS-AM <span class="hlt">precision</span> <span class="hlt">pointing</span> verification</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The Earth Observing System (EOS) AM mission requires tight <span class="hlt">pointing</span> knowledge to meet scientific objectives, in a spacecraft with low frequency flexible appendage modes. As the spacecraft controller reacts to various disturbance sources and as the inherent appendage modes are excited by this control action, verification of <span class="hlt">precision</span> <span class="hlt">pointing</span> knowledge becomes particularly challenging for the EOS-AM mission. As presently conceived, this verification includes a complementary set of multi-disciplinary analyses, hardware tests and real-time computer in the loop simulations, followed by collection and analysis of hardware test and flight data and supported by a comprehensive data base repository for validated program values.</p> <div class="credits"> <p class="dwt_author">Throckmorton, A.; Braknis, E.; Bolek, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">31</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20060037304&hterms=precision+pointing&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">Micro-<span class="hlt">Precision</span> Interferometer: <span class="hlt">Pointing</span> Control System</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">This paper describes the development of the wavefront tilt (<span class="hlt">pointing</span>) control system for the JPL Micro-<span class="hlt">Precision</span> Interferometer (MPI). This control system employs piezo-electric actuators and a digital imaging sensor with feedback compensation to reject errors in instrument <span class="hlt">pointing</span>. Stringent performance goals require large feedback, however, several characteristics of the plant tend to restrict the available bandwidth. A robust 7th-order wavefront tilt control system was successfully implemented on the MPI instrument, providing sufficient disturbance rejection performance to satisfy the established interference fringe visibility.</p> <div class="credits"> <p class="dwt_author">O'Brien, John</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">32</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50674011"> <span id="translatedtitle">A multi-<span class="hlt">precision</span> floating-<span class="hlt">point</span> adder</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper presents a multi-<span class="hlt">precision</span> floating-<span class="hlt">point</span> adder that can perform a high-<span class="hlt">precision</span> floating-<span class="hlt">point</span> addition, or multiple low-<span class="hlt">precision</span> floating-<span class="hlt">point</span> additions in parallel. The proposed design eliminates time consuming format conversion operations when it is operating in low-<span class="hlt">precision</span> modes. The proposed multi-<span class="hlt">precision</span> floating-<span class="hlt">point</span> adder has delay approximately equal to a standard double-<span class="hlt">precision</span> floating-<span class="hlt">point</span> adder.</p> <div class="credits"> <p class="dwt_author">M. M. Ozbilen; M. Gok</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">33</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19860062670&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">Space Telescope <span class="hlt">precision</span> <span class="hlt">pointing</span> control system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The Hubble Space Telescope has the most stringent <span class="hlt">pointing</span> requirements imposed on any spacecraft to date. The overall HST stability shall not exceed 0.007 arc-seconds rms. The <span class="hlt">Pointing</span> Control System utilizes fine guidance sensors and rate gyros for attitude reference and rate information. Control torques are provided by reaction wheels. A digital computer collects the sensor data, performs the control law computations, and sends torque commands to the reaction wheels. To attain this <span class="hlt">precision</span> <span class="hlt">pointing</span>, improvements were made to the rate gyros to lower their noise characteristics and to the reaction wheels to reduce their emitted vibration levels. The control system design was validated in a test sequence which progressed from model verification tests on an air-bearing to operations-oriented, closed loop testing on the assembled vehicle. A test system is described which allowed the simultaneous production of test case command loads for the flight computer and plots of predicted profiles to assist in test data analysis. Workarounds were required during system test to accommodate gyro biases and noise introduced into the closed loop system. Testing and analysis indicate that the HST will provide the capability to meet the requirements for <span class="hlt">precision</span> <span class="hlt">pointing</span>.</p> <div class="credits"> <p class="dwt_author">Beals, G. A.; Crum, R. C.; Dougherty, H. J.; Hegel, D. K.; Kelley, J. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">34</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6580900"> <span id="translatedtitle"><span class="hlt">Precise</span> <span class="hlt">positioning</span> of patients for radiation therapy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A number of immobilization schemes which permit <span class="hlt">precise</span> daily <span class="hlt">positioning</span> of patients for radiation therapy are discussed. Pretreatment and post-treatment radiographs have been taken with the patient in the treatment <span class="hlt">position</span> and analyzed to determine the amount of intratreatment movement. Studies of patients in the supine, seated and decubitus <span class="hlt">positions</span> indicate mean movements of less than 1 mm with a standard deviation of less than 1 mm. Patients immobilized in the seated <span class="hlt">position</span> with a bite block and a mask have a mean movement of about 0.5 mm +/- 0.3 mm (s.d.), and patients immobilized in the supine <span class="hlt">position</span> with their necks hyperextended for submental therapy evidence a mean movement of about 1.4 mm +/- 0.9 mm (s.d.). With the exception of those used for the decubitus <span class="hlt">position</span>, the immobilization devices are simply fabricated out of thermoplastic casting materials readily available from orthopedic supply houses. A study of day-to-day reproducibility of patient <span class="hlt">position</span> using laser alignment and pretreatment radiographs for final verification of <span class="hlt">position</span> indicates that the initial laser alignment can be used to <span class="hlt">position</span> a patient within 2.2 mm +/- 1.4 mm (s.d.) of the intended <span class="hlt">position</span>. These results indicate that rigid immobilization devices can improve the <span class="hlt">precision</span> of radiotherapy, which would be advantageous with respect to both tumor and normal tissue coverage in certain situations.</p> <div class="credits"> <p class="dwt_author">Verhey, L.J.; Goitein, M.; McNulty, P.; Munzenrider, J.E.; Suit, H.D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">35</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19920000741&hterms=global+positioning+system&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2522global%2Bpositioning%2Bsystem%2522"> <span id="translatedtitle"><span class="hlt">Precise</span> Applications Of The Global <span class="hlt">Positioning</span> System</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Report represents overview of Global <span class="hlt">Positioning</span> System (GPS). Emphasizes those aspects of theory, history, and status of GPS pertaining to potential utility for highly <span class="hlt">precise</span> scientific measurements. Current and anticipated applications include measurements of crustal motions in seismically active regions of Earth, measurements of rate of rotation of Earth and orientation of poles, tracking of non-GPS spacecraft in orbit around Earth, surveying, measurements of radio-signal-propagation delays, determinations of coordinates of ground stations, and transfer of <span class="hlt">precise</span> time signals worldwide.</p> <div class="credits"> <p class="dwt_author">Lichten, Stephen M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">36</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19780060474&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">pointing</span> and tracking system /PPTS/</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">As part of its advanced development work, JPL is developing a <span class="hlt">Precision</span> <span class="hlt">Pointing</span> and Tracking System (PPTS) for science platform control on unmanned planetary spacecraft. The PPTS will extend science capabilities on future missions by providing highly accurate (10 arcsec) and stable (0.2 arcsec) <span class="hlt">pointing</span> of the platform. Key features of the design include closed-loop tracking of target bodies using an optical sensor and decoupling of spacecraft dynamics via high-bandwidth, inertially stabilized control. This paper discusses the analyses and design. Computer simulations were used to establish the feasibility of the design approach and to verify that the performance requirements can be met. A breadboard demonstration of the entire system is expected in late 1980.</p> <div class="credits"> <p class="dwt_author">Brown, T. K.; Leblanc, D. R.; Mettler, E.; Gaalema, S. D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1978-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">37</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/2426822"> <span id="translatedtitle">Dual-Mode Quadruple <span class="hlt">Precision</span> Floating-<span class="hlt">Point</span> Adder</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Many scientific applications require more accurate computations than double <span class="hlt">precision</span> or double-extended <span class="hlt">precision</span> floating-<span class="hlt">point</span> arithmetic. This paper presents a dual-mode quadruple <span class="hlt">precision</span> floating-<span class="hlt">point</span> adder that also supports two parallel double <span class="hlt">precision</span> additions. A technique and modifications used to design the dual-mode quadruple <span class="hlt">precision</span> adder are also applied to implement a dual-mode double <span class="hlt">precision</span> adder, which supports one double <span class="hlt">precision</span> and</p> <div class="credits"> <p class="dwt_author">Ahmet Akkas</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">38</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19870013290&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">pointing</span> and control of flexible spacecraft</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The problem and long term objectives for the <span class="hlt">precision</span> <span class="hlt">pointing</span> and control of flexible spacecraft are given. The four basic objectives are stated in terms of two principle tasks. Under Task 1, robust low order controllers, improved structural modeling methods for control applications and identification methods for structural dynamics are being developed. Under Task 2, a lab test experiment for verification of control laws and system identification algorithms is being developed. For Task 1, work has focused on robust low order controller design and some initial considerations for structural modeling in control applications. For Task 2, work has focused on experiment design and fabrication, along with sensor selection and initial digital controller implementation. Conclusions are given.</p> <div class="credits"> <p class="dwt_author">Bantell, M. H., Jr.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">39</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19990008610&hterms=inertial+navigation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dinertial%2Bnavigation"> <span id="translatedtitle">Inertial <span class="hlt">Pointing</span> and <span class="hlt">Positioning</span> System</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">An inertial <span class="hlt">pointing</span> and control system and method for <span class="hlt">pointing</span> to a designated target with known coordinates from a platform to provide accurate <span class="hlt">position</span>, steering, and command information. The system continuously receives GPS signals and corrects Inertial Navigation System (INS) dead reckoning or drift errors. An INS is mounted directly on a <span class="hlt">pointing</span> instrument rather than in a remote location on the platform for-monitoring the terrestrial <span class="hlt">position</span> and instrument attitude. and for <span class="hlt">pointing</span> the instrument at designated celestial targets or ground based landmarks. As a result. the <span class="hlt">pointing</span> instrument and die INS move independently in inertial space from the platform since the INS is decoupled from the platform. Another important characteristic of the present system is that selected INS measurements are combined with predefined coordinate transformation equations and control logic algorithms under computer control in order to generate inertial <span class="hlt">pointing</span> commands to the <span class="hlt">pointing</span> instrument. More specifically. the computer calculates the desired instrument angles (Phi, Theta. Psi). which are then compared to the Euler angles measured by the instrument- mounted INS. and forms the <span class="hlt">pointing</span> command error angles as a result of the compared difference.</p> <div class="credits"> <p class="dwt_author">Yee, Robert (Inventor); Robbins, Fred (Inventor)</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">40</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/1885286"> <span id="translatedtitle">A Quadruple <span class="hlt">Precision</span> and Dual Double <span class="hlt">Precision</span> Floating-<span class="hlt">Point</span> Multiplier</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Double <span class="hlt">precision</span> floating-pointarithmetic is inadequate for many scientific computations. This paper presents the design of a quadruple <span class="hlt">precision</span> floating-<span class="hlt">point</span> multiplier that also supports two parallel double <span class="hlt">precision</span> multipli- cations. Since hardware support for quadruple <span class="hlt">precision</span> arithmetic is expensive, a new technique is presented that requiresmuch less hardwarethan a fully parallelquadruple <span class="hlt">precision</span> multiplier. With this implementation, quadruple <span class="hlt">precision</span> multiplication has a</p> <div class="credits"> <p class="dwt_author">Ahmet Akkas; Michael J. Schulte</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_1");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a style="font-weight: bold;">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a 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src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_2");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a style="font-weight: bold;">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_4");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">41</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/18217851"> <span id="translatedtitle">A comparison of localization judgments and <span class="hlt">pointing</span> <span class="hlt">precision</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We compared the <span class="hlt">precision</span> of perceptual localization and manual <span class="hlt">pointing</span>. A Gaussian blob was presented 6 degrees to the right or left of a central fixation spot on a CRT screen. Above and below the blob, vertical lines were displayed. On each trial, the blob was slightly offset to the right or left with respect to the lines. The subjects had to judge whether the blob appeared to the right or to the left of the vertical lines. At the same time, they had to <span class="hlt">point</span> to the center of the blob with their index finger. <span class="hlt">Precision</span> for perceived <span class="hlt">position</span> was significantly better than <span class="hlt">precision</span> for <span class="hlt">pointing</span>. Performance in these two tasks correlated highly between the subjects. Overall, subjects <span class="hlt">pointed</span> more leftward on trials where they judged the blob to be to the left of the lines. There was also a significant correlation for each subject between the <span class="hlt">pointing</span> error and the perceived location error, calculated by partialling out the effect of the physical offset. The results are in agreement with the idea that the signals determining the perceived location of an object are used to guide the motor system in <span class="hlt">pointing</span> toward it. PMID:18217851</p> <div class="credits"> <p class="dwt_author">Gegenfurtner, Karl R; Franz, Volker H</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">42</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013JGeod..87..361X"> <span id="translatedtitle">High-rate <span class="hlt">precise</span> <span class="hlt">point</span> <span class="hlt">positioning</span> (PPP) to measure seismic wave motions: an experimental comparison of GPS PPP with inertial measurement units</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">High-rate GPS has been widely used to construct displacement waveforms and to invert for source parameters of earthquakes. Almost all works on internal and external evaluation of high-rate GPS accuracy are based on GPS relative <span class="hlt">positioning</span>. We build an experimental platform to externally evaluate the accuracy of 50-Hz PPP displacement waveforms. Since the shake table allows motion in any of six degrees of freedom, we install an inertial measurement unit (IMU) to measure the attitude of the platform and transform the IMU displacements into the GPS coordinate system. The experimental results have shown that high-rate PPP can produce absolute horizontal displacement waveforms at the accuracy of 2-4 mm and absolute vertical displacement waveforms at the sub-centimeter level of accuracy within a short period of time. The significance of the experiments indicates that high-rate PPP is capable of detecting absolute seismic displacement waveforms at the same high accuracy as GPS relative <span class="hlt">positioning</span> techniques, but requires no fixed datum station. We have also found a small scaling error of IMU and a small time offset of misalignment between high-rate PPP and IMU displacement waveforms by comparing the amplitudes of and cross-correlating both the displacement waveforms.</p> <div class="credits"> <p class="dwt_author">Xu, Peiliang; Shi, Chuang; Fang, Rongxin; Liu, Jingnan; Niu, Xiaoji; Zhang, Quan; Yanagidani, Takashi</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">43</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..15.3740X"> <span id="translatedtitle">High-rate <span class="hlt">precise</span> <span class="hlt">point</span> <span class="hlt">positioning</span> (PPP) to measure seismic wave motions: An experimental comparison of GPS PPP with inertial measurement units</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">High-rate GPS has been widely used to construct displacement waveforms and to invert for source parameters of earthquakes. Almost all works on internal and external evaluation of high-rate GPS accuracy are based on GPS relative <span class="hlt">positioning</span>. We build an experimental platform to externally evaluate the accuracy of 50 Hz PPP displacement waveforms. Since the shake table allows motion in any of six degrees of freedom, we install an inertial measurement unit (IMU) to measure the attitude of the platform and transform the IMU displacements into the GPS coordinate system. The experimental results have shown that high-rate PPP can produce absolute horizontal displacement waveforms at the accuracy of 2 to 4 millimeters and absolute vertical displacement waveforms at the sub-centimeter level of accuracy within a short period of time. The significance of the experiments indicates that high-rate PPP is capable of detecting absolute seismic displacement waveforms at the same high accuracy as GPS relative <span class="hlt">positioning</span> techniques but requires no fixed datum station. We have also found a small scaling error of IMU and a small time offset of misalignment between high-rate PPP and IMU displacement waveforms by comparing the amplitudes of and cross-correlating both the displacement waveforms. For more details on this talk, one can now get access to the on-line-first version of our Journal of Geodesy paper: J Geod, DOI 10.1007/s00190-012-0606-z</p> <div class="credits"> <p class="dwt_author">Xu, Peiliang; Shi, Chuang; Fang, Rongxin; Liu, Jingnan; Niu, Xiaoji; Zhang, Quan; Yanagidani, Takashi</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">44</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19910049307&hterms=precision+pointing&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">pointing</span> control for an orbital earth observing system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The design concept developed for the <span class="hlt">pointing</span> system of the high-resolution imaging spectrometer (HIRIS) which will be flown on one of NASA's earth observing system platforms is presented. The instrument is an F/5.4-aperture spectrometer with a focal length of 1222 mm, and it uses a <span class="hlt">precision</span> two-axis gimballed mirror <span class="hlt">pointing</span> system to image and track targets. <span class="hlt">Pointing</span> accuracy of better than 585 arcsec (peak-to-peak), and <span class="hlt">pointing</span> jitter of less than 2.65 arcsec in 33 ms are ensured through the use of gimbal <span class="hlt">position</span> and basebody rate sensors. A state-space controller implemented with a digital computer is used to provide a <span class="hlt">position</span> loop bandwidth of 1 Hz and a rate loop bandwidth of 7 Hz. An overview of the system design and flight hardware is given, the development of the controller architecture is addressed, and a simulation assessment of the <span class="hlt">pointing</span> system that takes into consideration issues such as nonlinear effects, sensor noise, and noncollocated sensors and actuators in a flexible structure is discussed.</p> <div class="credits"> <p class="dwt_author">Robeck, Linda S.; Rathbun, David B.; Lehman, David H.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">45</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17070889"> <span id="translatedtitle">Initial visual information determines endpoint <span class="hlt">precision</span> for rapid <span class="hlt">pointing</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We investigated how visual noise in the initial estimate of target location affects <span class="hlt">precision</span> for rapid <span class="hlt">pointing</span>. Visual localization thresholds (an error measure) rise systematically with eccentricity, doubling at eccentricities of a degree or less. Previous work, which we confirmed, has shown that the <span class="hlt">precision</span> of <span class="hlt">pointing</span>, measured by the standard deviation, to a single isolated target is relatively constant over small lateral extents near the midline, and that <span class="hlt">pointing</span> error is substantially larger than visual error. We used target uncertainty (randomly chosen locations) to greatly increase visual noise so that we could explore the influence of visual noise on <span class="hlt">pointing</span> error. We compared <span class="hlt">precision</span> for comparable visual and <span class="hlt">pointing</span> tasks as a function of target eccentricity. The target was presented for 110 ms at one of eight isoeccentric locations, chosen at random. Under these conditions, <span class="hlt">pointing</span> error increased significantly with increasing target eccentricity. Beyond 4 degrees eccentricity, visual thresholds and <span class="hlt">pointing</span> error were identical. Even when the target remained visible until the movement was completed, initial target eccentricity affected <span class="hlt">pointing</span> error. The quality of visual information varies with task demands, and therefore so does its influence on endpoint <span class="hlt">precision</span>. Our results demonstrate that the initial visual information about target location can limit endpoint <span class="hlt">precision</span>, even over as small a range as 12 degrees in the central visual field (a lateral extent of +/-8.5 cm at the midline). PMID:17070889</p> <div class="credits"> <p class="dwt_author">Ma-Wyatt, Anna; McKee, Suzanne P</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">46</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19910014760&hterms=global+earthquake+map&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dglobal%2Bearthquake%2Bmap"> <span id="translatedtitle">High <span class="hlt">precision</span> applications of the global <span class="hlt">positioning</span> system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The Global <span class="hlt">Positioning</span> System (GPS) is a constellation of U.S. defense navigation satellites which can be used for military and civilian <span class="hlt">positioning</span> applications. A wide variety of GPS scientific applications were identified and <span class="hlt">precise</span> <span class="hlt">positioning</span> capabilities with GPS were already demonstrated with data available from the present partial satellite constellation. Expected applications include: measurements of Earth crustal motion, particularly in seismically active regions; measurements of the Earth's rotation rate and pole orientation; high-<span class="hlt">precision</span> Earth orbiter tracking; surveying; measurements of media propagation delays for calibration of deep space radiometric data in support of NASA planetary missions; determination of <span class="hlt">precise</span> ground station coordinates; and <span class="hlt">precise</span> time transfer worldwide.</p> <div class="credits"> <p class="dwt_author">Lichten, Stephen M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">47</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010JPhCS.203a2133F"> <span id="translatedtitle"><span class="hlt">Positioning</span>, alignment and absolute <span class="hlt">pointing</span> of the ANTARES neutrino telescope</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A <span class="hlt">precise</span> detector alignment and absolute <span class="hlt">pointing</span> is crucial for <span class="hlt">point</span>-source searches. The ANTARES neutrino telescope utilises an array of hydrophones, tiltmeters and compasses for the relative <span class="hlt">positioning</span> of the optical sensors. The absolute calibration is accomplished by long-baseline low-frequency triangulation of the acoustic reference devices in the deep-sea with a differential GPS system at the sea surface. The absolute <span class="hlt">pointing</span> can be independently verified by detecting the shadow of the Moon in cosmic rays.</p> <div class="credits"> <p class="dwt_author">Fehr, F.; Distefano, C.; Antares Collaboration</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">48</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.416.5421&rank=13"> <span id="translatedtitle">Dilution of <span class="hlt">Precision</span> estimationusing single frequency Global <span class="hlt">Positioning</span> System receiver</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Global <span class="hlt">Positioning</span> System (GPS)is a satellite basedradio navigation systemintended to provide highly accurate three dimensional <span class="hlt">positions</span> and <span class="hlt">precise</span> time on a continuous global basis.Usually, GPS accuracy is limited by several factors such as atmospheric, receiver and satellite based errors. Among them, Dilution of <span class="hlt">Precision</span> (DOP) and multipath errors are very important to investigate the error for improving <span class="hlt">positional</span> accuracy. In this paper, single frequency receiver data analysis in static mode is carried out. Using the GPS data, Horizontal Dilution of <span class="hlt">Precision</span> (HDOP) results were presented. The presented preliminary results would be useful for developing suitable techniques for improving single frequency GPS <span class="hlt">positional</span> accuracy by taking the HDOP errors into the consideration. Keywords-GPS, NMEA and HDOP.</p> <div class="credits"> <p class="dwt_author">Shalem Raj Meduri; Dr. P. S. Bramhan</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">49</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19820062085&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">Magnetic suspension - The next generation in <span class="hlt">precision</span> <span class="hlt">pointing</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Today's large optical experiments, both free-flying and Shuttle-borne, are finding an increasing need for a stable <span class="hlt">pointing</span> platform in a vibration environment. As the resolution of optical systems has improved, conventional techniques for isolation and <span class="hlt">pointing</span> have become less attractive. This paper describes the present state of the art in magnetic suspension <span class="hlt">pointing</span> systems. This technology combines the functions of translational isolation and <span class="hlt">precision</span> <span class="hlt">pointing</span> to achieve performance in the 0.01 arcsec range, in the presence of disturbances such as random noise or reaction jet firings. Ongoing technology refinements and their importance to the experiment community are also discussed. The key to these refinements is a high-resolution, vibrating quartz force sensor that will improve <span class="hlt">pointing</span> stability.</p> <div class="credits"> <p class="dwt_author">Hamilton, B. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">50</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19970004991&hterms=space+time+warp&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dspace%2Btime%2Bwarp"> <span id="translatedtitle">Astrophysical Adaptation of <span class="hlt">Points</span>, the <span class="hlt">Precision</span> Optical Interferometer in Space</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><span class="hlt">POINTS</span> (<span class="hlt">Precision</span> Optical INTerferometer in Space) would perform microarcsecond optical astrometric measurements from space, yielding submicroarcsecond astrometric results from the mission. It comprises a pair of independent Michelson stellar interferometers and a laser metrology system that measures both the critical starlight paths and the angle between the baselines. The instrument has two baselines of 2 m, each with two subapertures of 35 cm; by articulating the angle between the baselines, it observes targets separated by 87 to 93 deg. <span class="hlt">POINTS</span> does global astrometry, i.e., it measures widely separated targets, which yields closure calibration, numerous bright reference stars, and absolute parallax. Simplicity, stability, and the mitigation of systematic error are the central design themes. The instrument has only three moving-part mechanisms, and only one of these must move with sub-milliradian <span class="hlt">precision</span>; the other two can tolerate a <span class="hlt">precision</span> of several tenths of a degree. Optical surfaces preceding the beamsplitter or its fold flat are interferometrically critical; on each side of the interferometer, there are only three such. Thus, light loss and wavefront distortion are minimized. <span class="hlt">POINTS</span> represents a minimalistic design developed ab initio for space. Since it is intended for astrometry, and therefore does not require the u-v-plane coverage of an imaging, instrument, each interferometer need have only two subapertures. The design relies on articulation of the angle between the interferometers and body <span class="hlt">pointing</span> to select targets; the observations are restricted to the 'instrument plane.' That plane, which is fixed in the <span class="hlt">pointed</span> instrument, is defined by the sensitive direction for the two interferometers. Thus, there is no need for siderostats and moving delay lines, which would have added many <span class="hlt">precision</span> mechanisms with rolling and sliding parts that would be required to function throughout the mission. Further, there is no need for a third interferometer, as is required when out-of-plane observations are made. An instrument for astrometry, unlike those for imaging, can be compact and yet scientifically productive. The <span class="hlt">POINTS</span> instrument is compact and therefore requires no deployment of <span class="hlt">precision</span> structures, has no low-frequency (i.e., under 100 Hz) vibration modes, and is relatively easy to control thermally. Because of its small size and mass, it is easily and quickly repointed between observations. Further, because of the low mass, it can be economically launched into high Earth orbit which, in conjunction with a solar shield, yields nearly unrestricted sky coverage and a stable thermal environment.</p> <div class="credits"> <p class="dwt_author">Reasenberg, Robert D.; Babcock, Robert W.; Murison, Marc A.; Noecker, M. Charles; Phillips, James D.; Schumaker, Bonny L.; Ulvestad, James S.; McKinley, William; Zielinski, Robert J.; Lillie, Charles F.</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">51</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://people.musc.edu/~elg26/talks/PointEstimation.ppt"> <span id="translatedtitle"><span class="hlt">Point</span> Estimation: Odds Ratios, Hazard Ratios, Risk Differences, <span class="hlt">Precision</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This site provides a Power<span class="hlt">Point</span> presentation, created by Dr. Elizabeth Garrett-Mayer of Johns Hopkins University, of a lesson and examples of <span class="hlt">point</span> estimation, odds ratios, hazard ratios, risk differences and <span class="hlt">precision</span>. The presentations is quite thorough. The author attempts to define, provide examples of, and then show the application of almost every concept. The presentation follows a easily followed and logical order. Mathematical formulas are intertwined within the slides. If further research is necessary, the author has provided a list of references and cites them during the presentation.</p> <div class="credits"> <p class="dwt_author">Garrett-Mayer, Elizabeth</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-02-11</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">52</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19890025320&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">Reactionless gimbal actuator for <span class="hlt">precision</span> <span class="hlt">pointing</span> of large payloads</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A novel actuator for application to <span class="hlt">precision</span> <span class="hlt">pointing</span> gimbal systems is described. The new actuator, dubbed the Reactuator, is capable of large output torques for payload <span class="hlt">pointing</span> while minimizing reaction torques that can excite gimbal support structure. The Reactuator is able to approach reactionless operation by using an integral wheel to absorb the reaction torques. The advantages that result are described through analysis and simulation examples. Methods for designing control algorithms for the Reactuator are discussed and the results of preliminary breadboard tests are presented.</p> <div class="credits"> <p class="dwt_author">Laskin, R. A.; Kopf, E. H.; Sirlin, S. W.; Spanos, J. T.; Wiktor, P. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">53</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19860004344&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">pointing</span> using a dual-wedge scanner</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A system was developed for calibrating and <span class="hlt">precisely</span> <span class="hlt">pointing</span> a germanium dual-wedge scanner for a CO2 Doppler lidar from an airborne platform. The equations implemented in <span class="hlt">pointing</span> the scanner and those in the iterative calibration program, which combines available data with estimated parameters of the scanner orientation relative to the axes of the aircraft's inertial navigation system to arrive at corrected scanner parameters are described. The effect of specific error conditions on program performance and the results of the program when used on 1981 test data are investigated.</p> <div class="credits"> <p class="dwt_author">Amirault, C. T.; Dimarzio, C. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">54</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24455466"> <span id="translatedtitle">Design of a reversible single <span class="hlt">precision</span> floating <span class="hlt">point</span> subtractor.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">In recent years, Reversible logic has emerged as a major area of research due to its ability to reduce the power dissipation which is the main requirement in the low power digital circuit design. It has wide applications like low power CMOS design, Nano-technology, Digital signal processing, Communication, DNA computing and Optical computing. Floating-<span class="hlt">point</span> operations are needed very frequently in nearly all computing disciplines, and studies have shown floating-<span class="hlt">point</span> addition/subtraction to be the most used floating-<span class="hlt">point</span> operation. However, few designs exist on efficient reversible BCD subtractors but no work on reversible floating <span class="hlt">point</span> subtractor. In this paper, it is proposed to present an efficient reversible single <span class="hlt">precision</span> floating-<span class="hlt">point</span> subtractor. The proposed design requires reversible designs of an 8-bit and a 24-bit comparator unit, an 8-bit and a 24-bit subtractor, and a normalization unit. For normalization, a 24-bit Reversible Leading Zero Detector and a 24-bit reversible shift register is implemented to shift the mantissas. To realize a reversible 1-bit comparator, in this paper, two new 3x3 reversible gates are proposed The proposed reversible 1-bit comparator is better and optimized in terms of the number of reversible gates used, the number of transistor count and the number of garbage outputs. The proposed work is analysed in terms of number of reversible gates, garbage outputs, constant inputs and quantum costs. Using these modules, an efficient design of a reversible single <span class="hlt">precision</span> floating <span class="hlt">point</span> subtractor is proposed. Proposed circuits have been simulated using Modelsim and synthesized using Xilinx Virtex5vlx30tff665-3. The total on-chip power consumed by the proposed 32-bit reversible floating <span class="hlt">point</span> subtractor is 0.410 W. PMID:24455466</p> <div class="credits"> <p class="dwt_author">Anantha Lakshmi, Av; Sudha, Gf</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">55</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014AAS...22412211B"> <span id="translatedtitle">High <span class="hlt">Precision</span> <span class="hlt">Pointing</span> Stability and Control for Exoplanet Missions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Exoplanet imaging and characterization space observatories require high <span class="hlt">precision</span> <span class="hlt">pointing</span> stability and stability. We have developed a toolbox of sensors, actuators and algorithms along with a systems approach to meet the demanding needs of these missions. Grown from developments and experience gained from high <span class="hlt">precision</span> Earth remote sensing missions such as the WorldView satellites, as well as high performance astrophysics missions such as Kepler and JWST, these capabilities are enabling for a wide range of future missions. The approaches take advantage of highly flexible software architectures; Enhanced ground simulation capabilities for system tuning and verification and validation; Testing capabilities to verify our modelling; High <span class="hlt">precision</span> sensors including sub-arc-second star trackers and fine guidance sensors; High bandwidth fast steering mirrors for optical path control; and high <span class="hlt">precision</span> reaction wheels and control moment gyros for overall observatory control. Many of these capabilities coupled with innovative thinking have been applied to the recent Kepler mission to enable the K2 extended mission concept.</p> <div class="credits"> <p class="dwt_author">Barnes, Arnold; Troeltzsch, John; Wiemer, Doug</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">56</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/27073887"> <span id="translatedtitle">High <span class="hlt">Precision</span> <span class="hlt">Position</span> Control Using an Adaptive Friction Compensation Approach</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The presented work concerns the development of a trajectory tracking controller which is able to improve clearly the dynamical performance of a high <span class="hlt">precision</span> <span class="hlt">positioning</span> stage. Experiments in the pre-rolling and rolling friction regimes are conducted and a hybrid parameter estimation algorithm is used to fit the parameters of a simple dynamic friction model based on experimental data. Further experiments</p> <div class="credits"> <p class="dwt_author">Arvid Amthor; Stephan Zschaeck; Christoph Ament</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">57</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19870039352&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle"><span class="hlt">Precision</span> optical <span class="hlt">pointing</span> and tracking from spacecraft with vibrational noise</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The results of an investigation of the performance of three basic <span class="hlt">precision</span> <span class="hlt">pointing</span> and tracking control subsystems considered for application to satellite to satellite optical communication missions are discussed. The three-control subsystems include: (1) gyro-stabilized, (2) mass-stabilized and (3) complementary filter. The sources of error included in the analysis included: (1) sensor noise from the optical detector, (2) host satellite baseframe vibrational noise and (3) frictional and bearing noise. The measured vibrational and disturbance data from the LANDSAT satellite was used to generate the power spectral density parameter needed to model the baseframe noise environments of the two satellites used for the evaluation. The results of the study indicate that the 1 microradian rms <span class="hlt">pointing</span> and tracking accuracy may be achieved with either the gyro-stabilized or the complementary filter approach.</p> <div class="credits"> <p class="dwt_author">Held, K. J.; Barry, J. D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">58</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19830058720&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">A system for load isolation and <span class="hlt">precision</span> <span class="hlt">pointing</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A system capable of satisfying the accuracy and stability requirements dictated by Shuttle-borne payloads utilizing large optics has been under joint NASA/Sperry development. This device, denoted the Annular Suspension and <span class="hlt">Pointing</span> System, employs a unique combination of conventional gimbals and magnetic bearing actuators, thereby providing for the complete isolation of the payload from its external environment, as well as for extremely accurate and stable <span class="hlt">pointing</span> (equal to about 0.01 arcsec). This effort has been pursued through the fabrication and laboratory evaluation of engineering model hardware. Results from these tests have been instrumental in generating high fidelity computer simulations of this load isolation and <span class="hlt">precision</span> <span class="hlt">pointing</span> system, and in permitting confident predictions of the system's on-orbit performance. The applicability of this system to the Solar Optical Telescope mission has been examined using the computer simulation. The worst case <span class="hlt">pointing</span> error predicted for this payload while subjected to vernier reaction control system thruster firings and crew motions aboard the Shuttle was approximately 0.006 arcsec.</p> <div class="credits"> <p class="dwt_author">Keckler, C. R.; Hamilton, B. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">59</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850060311&hterms=Long+Baseline+Positioning+System&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DLong%2BBaseline%2BPositioning%2BSystem"> <span id="translatedtitle">A comparison of four <span class="hlt">precise</span> global <span class="hlt">positioning</span> system geodetic receivers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Four <span class="hlt">precise</span> global <span class="hlt">positioning</span> system (GPS) geodetic receivers were operated simultaneously in January and February 1984 over ten baselines ranging in distance from 13 to 1304 km. Several of the baselines had been previously measured using very long baseline interferometry and, therefore, provide very good standards to which the satellite results can be compared. Results of these experiments are presented along with a brief description of each receiver and the associated analysis techniques.</p> <div class="credits"> <p class="dwt_author">Goad, C. C.; Sims, M. L.; Young, L. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">60</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19830011846&hterms=markers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmarkers"> <span id="translatedtitle"><span class="hlt">Precision</span> optical angular <span class="hlt">position</span> marker system for rotating machinery</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">An optical system is described which generates one or more markers of the angular shaft <span class="hlt">position</span> of rotating machinery. The system consists of a light source, an optical cable, a machinery mounted lens assembly, a light detector, and a signal conditioner. Light reflected by targets on the rotor is converted to a digital output signal. The system is highly immune to extreme environments of vibration and temperature and achieved a 0.002 percent <span class="hlt">precision</span> under operational test conditions.</p> <div class="credits"> <p class="dwt_author">Barranger, J. P.</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_2");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a style="font-weight: bold;">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">61</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19940009484&hterms=global+positioning+system&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2522global%2Bpositioning%2Bsystem%2522"> <span id="translatedtitle">Helicopter <span class="hlt">precision</span> approach capability using the Global <span class="hlt">Positioning</span> System</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The period between 1 July and 31 December, 1992, was spent developing a research plan as well as a navigation system document and flight test plan to investigate helicopter <span class="hlt">precision</span> approach capability using the Global <span class="hlt">Positioning</span> System (GPS). In addition, all hardware and software required for the research was acquired, developed, installed, and verified on both the test aircraft and the ground-based reference station.</p> <div class="credits"> <p class="dwt_author">Kaufmann, David N.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">62</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AcASn..53..153S"> <span id="translatedtitle">Analysis on the Accuracy of Celestial <span class="hlt">Positioning</span> Based on the SLR <span class="hlt">Precise</span> Orbit</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The <span class="hlt">precise</span> orbit of the satellite Ajisai is derived from the normal <span class="hlt">point</span> data of the satellite's laser ranging obtained from the International Laser Ranging Service (ILRS) with a RMS <span class="hlt">precision</span> better than 3 centimeters. The accuracy of the celestial <span class="hlt">positioning</span> data is analyzed based on the <span class="hlt">precise</span> orbit, resulting an external accuracy of 3''. The celestial <span class="hlt">positioning</span> data is obtained by the 40 cm optical electric telescope in Changchun observatory. The internal accuracy estimated by the orbit determination solely using the celestial <span class="hlt">positioning</span> data is better than 3''. The accuracy of above orbit is better than 100 m in the J2000.0 coordinate within the observation pass. The data analysis on Jason-1 by the same method yields a similar result as Ajisai. The analysis on the accuracy shows that less reference stars lead to worse celestial <span class="hlt">positioning</span> accuracy. It is proposed that the proportion of observations with least reference stars can be one of the quality criteria.</p> <div class="credits"> <p class="dwt_author">Sun, M. G.; Liu, C. Z.; Fan, C. B.; Zhao, G.; Li, Z. W.; Liang, Z. P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">63</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002SPIE.4757..214G"> <span id="translatedtitle">Integrated modeling and analysis methodology for <span class="hlt">precision</span> <span class="hlt">pointing</span> applications</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Space-based optical systems that perform tasks such as laser communications, Earth imaging, and astronomical observations require <span class="hlt">precise</span> line-of-sight (LOS) <span class="hlt">pointing</span>. A general approach is described for integrated modeling and analysis of these types of systems within the MATLAB/Simulink environment. The approach can be applied during all stages of program development, from early conceptual design studies to hardware implementation phases. The main objective is to predict the dynamic <span class="hlt">pointing</span> performance subject to anticipated disturbances and noise sources. Secondary objectives include assessing the control stability, levying subsystem requirements, supporting <span class="hlt">pointing</span> error budgets, and performing trade studies. The integrated model resides in Simulink, and several MATLAB graphical user interfaces (GUI"s) allow the user to configure the model, select analysis options, run analyses, and process the results. A convenient parameter naming and storage scheme, as well as model conditioning and reduction tools and run-time enhancements, are incorporated into the framework. This enables the proposed architecture to accommodate models of realistic complexity.</p> <div class="credits"> <p class="dwt_author">Gutierrez, Homero L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">64</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010SPIE.7733E..16P"> <span id="translatedtitle">High-<span class="hlt">precision</span> <span class="hlt">pointing</span> with the Sardinia Radio Telescope</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present here the systems aimed to measure and minimize the <span class="hlt">pointing</span> errors for the Sardinia Radio Telescope: they consist of an optical telescope to measure errors due to the mechanical structure deformations and a lasers system for the errors due to the subreflector displacement. We show here the results of the tests that we have done on the Medicina 32 meters VLBI radio telescope. The measurements demonstrate we can measure the <span class="hlt">pointing</span> errors of the mechanical structure, with an accuracy of about ~1 arcsec. Moreover, we show the technique to measure the displacement of the subreflector, placed in the SRT at 22 meters from the main mirror, within +/-0.1 mm from its optimal <span class="hlt">position</span>. These measurements show that we can obtain the needed accuracy to correct also the non repeatable <span class="hlt">pointing</span> errors, which arise on time scale varying from seconds to minutes.</p> <div class="credits"> <p class="dwt_author">Poppi, Sergio; Pernechele, Claudio; Pisanu, Tonino; Morsiani, Marco</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">65</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1007/s00267-004-0270-z"> <span id="translatedtitle">Mapping stream habitats with a global <span class="hlt">positioning</span> system: Accuracy, <span class="hlt">precision</span>, and comparison with traditional methods</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">We tested the <span class="hlt">precision</span> and accuracy of the Trimble GeoXT??? global <span class="hlt">positioning</span> system (GPS) handheld receiver on <span class="hlt">point</span> and area features and compared estimates of stream habitat dimensions (e.g., lengths and areas of riffles and pools) that were made in three different Oklahoma streams using the GPS receiver and a tape measure. The <span class="hlt">precision</span> of differentially corrected GPS (DGPS) <span class="hlt">points</span> was not affected by the number of GPS <span class="hlt">position</span> fixes (i.e., geographic location estimates) averaged per DGPS <span class="hlt">point</span>. Horizontal error of <span class="hlt">points</span> ranged from 0.03 to 2.77 m and did not differ with the number of <span class="hlt">position</span> fixes per <span class="hlt">point</span>. The error of area measurements ranged from 0.1% to 110.1% but decreased as the area increased. Again, error was independent of the number of <span class="hlt">position</span> fixes averaged per polygon corner. The estimates of habitat lengths, widths, and areas did not differ when measured using two methods of data collection (GPS and a tape measure), nor did the differences among methods change at three stream sites with contrasting morphologies. Measuring features with a GPS receiver was up to 3.3 times faster on average than using a tape measure, although signal interference from high streambanks or overhanging vegetation occasionally limited satellite signal availability and prolonged measurements with a GPS receiver. There were also no differences in <span class="hlt">precision</span> of habitat dimensions when mapped using a continuous versus a <span class="hlt">position</span> fix average GPS data collection method. Despite there being some disadvantages to using the GPS in stream habitat studies, measuring stream habitats with a GPS resulted in spatially referenced data that allowed the assessment of relative habitat <span class="hlt">position</span> and changes in habitats over time, and was often faster than using a tape measure. For most spatial scales of interest, the <span class="hlt">precision</span> and accuracy of DGPS data are adequate and have logistical advantages when compared to traditional methods of measurement. ?? 2006 Springer Science+Business Media, Inc.</p> <div class="credits"> <p class="dwt_author">Dauwalter, D. C.; Fisher, W. L.; Belt, K. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">66</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/1951772"> <span id="translatedtitle"><span class="hlt">Precise</span> On-line <span class="hlt">Position</span> Measurement for Particle Therapy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">An on-line beam <span class="hlt">position</span> monitoring and regular beam stability tests are of utmost importance for the Quality Assurance (QA) of the patient treatment at any particle therapy facility. The Gantry${0.5 mm}2$ at the Paul Scherrer Institute uses a strip ionization chamber for the on-line beam <span class="hlt">position</span> verification. The design of the strip chamber placed in the beam in front of the patient allows for a small beam penumbra in order to achieve a high-quality lateral beam delivery. The detector granularity and the low noise allow the reconstruction of the signals offered by Gantry${0.5 mm}2$ with a <span class="hlt">precision</span> of about 0.1 mm. The frond-end electronics and the whole data processing sequence have been optimized for minimizing the dead time between the beam applications to about 2 ms: the charge collection is performed in about 1 ms, read-out takes place in 100 $\\mu$s while data verification and logging are completed in less than 1 ms. The sub-millimeter <span class="hlt">precision</span> of the lateral reconstruction allows the dose inhomogenei...</p> <div class="credits"> <p class="dwt_author">Actis, O; König, S</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">67</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850060310&hterms=Long+Baseline+Positioning+System&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DLong%2BBaseline%2BPositioning%2BSystem"> <span id="translatedtitle">GPS-based satellite tracking system for <span class="hlt">precise</span> <span class="hlt">positioning</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">NASA is developing a Global <span class="hlt">Positioning</span> System (GPS) based measurement system to provide <span class="hlt">precise</span> determination of earth satellite orbits, geodetic baselines, ionospheric electron content, and clock offsets between worldwide tracking sites. The system will employ variations on the differential GPS observing technique and will use a network of nine fixed ground terminals. Satellite applications will require either a GPS flight receiver or an on-board GPS beacon. Operation of the system for all but satellite tracking will begin by 1988. The first major satellite application will be a demonstration of decimeter accuracy in determining the altitude of TOPEX in the early 1990's. By then the system is expected to yield long-baseline accuracies of a few centimeters and instantaneous time synchronization to 1 ns.</p> <div class="credits"> <p class="dwt_author">Yunck, T. P.; Melbourne, W. G.; Thornton, C. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">68</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70110624"> <span id="translatedtitle">An approach for filtering hyperbolically <span class="hlt">positioned</span> underwater acoustic telemetry data with <span class="hlt">position</span> <span class="hlt">precision</span> estimates</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">The use of <span class="hlt">position</span> <span class="hlt">precision</span> estimates that reflect the confidence in the <span class="hlt">positioning</span> process should be considered prior to the use of biological filters that rely on a priori expectations of the subject’s movement capacities and tendencies. <span class="hlt">Position</span> confidence goals should be determined based upon the needs of the research questions and analysis requirements versus arbitrary selection, in which filters of previous studies are adopted. Data filtering with this approach ensures that data quality is sufficient for the selected analyses and presents the opportunity to adjust or identify a different analysis in the event that the requisite <span class="hlt">precision</span> was not attained. Ignoring these steps puts a practitioner at risk of reporting errant findings.</p> <div class="credits"> <p class="dwt_author">Meckley, Trevor D.; Holbrook, Christopher M.; Wagner, C. Michael; Binder, Thomas R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">69</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19760010101&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">Pointing</span> Control System (PPCS) star tracker test</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Tests performed on the TRW <span class="hlt">precision</span> star tracker are described. The unit tested was a two-axis gimballed star tracker designed to provide star LOS data to an accuracy of 1 to 2 sec. The tracker features a unique bearing system and utilizes thermal and mechanical symmetry techniques to achieve high <span class="hlt">precision</span> which can be demonstrated in a one g environment. The test program included a laboratory evaluation of tracker functional operation, sensitivity, repeatibility, and thermal stability.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1972-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">70</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005PhDT........38R"> <span id="translatedtitle">Model, control and performance of a six degree-of-freedom <span class="hlt">precision</span> <span class="hlt">pointing</span> and tracking system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this dissertation, a six degree-of-freedom (6-DOF) <span class="hlt">precision</span> <span class="hlt">pointing</span> and tracking system is integrated to demonstrate its laser <span class="hlt">pointing</span> and tracking capability in ambient laboratory environment. Such a demonstration is intended for potential high accuracy <span class="hlt">pointing</span> and smooth angular slewing applications in space, such as free-space laser communications among satellites. The key technology adopted is the slotless permanent magnet (PM) self-bearing motor (SBM), which is first utilized to fully provide radial bearing and motoring functionality simultaneously in a novel 6-DOF magnetic actuator. The <span class="hlt">precision</span> actuator incorporates two SBMs and one active magnetic bearing (AMB), and thus allows for a complete electromagnetic suspension and <span class="hlt">precision</span> non-contact <span class="hlt">pointing</span>. The sensing scheme is critical to the feedback control of the open loop unstable magnetic actuator. Among various sensors used, the unique linear tape encoding strategy uses the same concept as in the SBM and provides high resolution and non-contact measurement for radial and angular displacements simultaneously. To accurately characterize current and negative stiffness gains in the linearized force-current-displacement relation of the large-scale SBM, the analytical force and torque expressions are derived using the Maxwell stress tensor method. A general two-dimensional (2-D) magnetic field analysis in the large effective air gap is conducted and the field components due to thick windings and PMs are formulated in explicit forms. All analytical solutions are validated by the electromagnetic finite element analyses (FEA). An analytical representation of the overall dynamic system is presented for linear controller design. Six decoupled proportional-integral-derivative (PID) controllers are designed and a real-time digital feedback control system is implemented. Intensive experiments are carried out to evaluate the closed loop performance. The actuator is capable of smooth angular slewing while maintaining good stabilization. Enhanced by a switching algorithm for smooth switches between encoder and <span class="hlt">position</span> sensing device (PSD) feedback loops, the overall system demonstrates successful acquisition and reacquisition as well as <span class="hlt">precision</span> <span class="hlt">pointing</span> and tracking capability of the laser beam. This 6-DOF <span class="hlt">precision</span> <span class="hlt">pointing</span> and tracking system achieves a <span class="hlt">pointing</span> and tracking accuracy below 1 murad with an angular resolution of 754 nrad over a large azimuth range of +/-45° using a single actuator.</p> <div class="credits"> <p class="dwt_author">Ren, Zhaohui</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">71</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/752899"> <span id="translatedtitle">Robot <span class="hlt">positioning</span> based on <span class="hlt">point-to-point</span> motion capability</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This paper presents an optimal search method for determining the base location of a robot manipulator so that the robot can have a designated <span class="hlt">point-to-point</span> (PTP) motion capabilities. Based on the topological characterization of the manipulator workspace and the definitions of various p-connectivity, a computational method is developed for enumerating various PTP motion capabilities into quantitative cost functions. Then an unconstrained search by minimizing the cost function yields the task feasible location of the robot base. This methodology is useful for placement of mobile manipulators and robotic workcell layout design.</p> <div class="credits"> <p class="dwt_author">Park, Y. S.; Cho, H. S.; Koh, K. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-03-20</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">72</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009SPIE.7509E..0IW"> <span id="translatedtitle">Analysis on working status of support device with 3-<span class="hlt">point</span> used in high <span class="hlt">precision</span> system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The support device with 3-<span class="hlt">point</span> are widely used in many kinds of support systems. However, some problems will emerge when the device is used in high <span class="hlt">precision</span> system. For example, in the self-adaptive optical system, the different deformation of each support <span class="hlt">point</span> will cause the dissimilar slope of the supported part of the system, will cause the <span class="hlt">position</span> error of segment mirror. This paper, using elastic mechanics theory to calculate the elastic deformation, calculates the elasticity deformation of steel balls in the device; based on the principle of optical auto-collimation, tests the related deformations of the three support <span class="hlt">points</span> under different normal loads; according to the calculation and the experimentation, compares and analyzes the results of calculation and experimentation, sums up the relationship between deformation and support sphere diameter and load value; lastly, proposes the principia to determine the diameter of the balls in high <span class="hlt">precision</span> system, and provides reformative scheme to design a better support devices with 3-<span class="hlt">point</span>. The results of this paper have been used in the design and development of self-adaptive optical system.</p> <div class="credits"> <p class="dwt_author">Wang, Zhi-shan; Zhao, Yue-jin</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">73</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ll.mit.edu/hpec/agendas/proc03/pdfs/zhao.pdf"> <span id="translatedtitle"><span class="hlt">Precision</span> Modeling and<span class="hlt">Precision</span> Modeling and BitwidthBitwidth Optimization of FloatingOptimization of Floating--<span class="hlt">PointPoint</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">????? ?? ? ? ? ? ? ? )^,^( ^)^,^( )^,^( ^)^,^( ),( |)^,^(),(| #12;Propagation Error (2)Propagation Error (2) Equation: MULT: ADD: SQRT: yyxxyxpz kk yxf yxf yxf xyxf<span class="hlt">Precision</span> Modeling Methodology ? Behavioral Profiling ? Error Models of FP Operations ­ Rounding Error ­ Propagation of an operation : Propagation Error(PE) + Rounding Error(RE) ))^^(^^()^^()^^()( yxfpyxyxyxyxfpyx ??????????? yx</p> <div class="credits"> <p class="dwt_author">Kepner, Jeremy</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">74</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19860047043&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">Payload isolation and <span class="hlt">precision</span> <span class="hlt">pointing</span> for the 1990's</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The design of a <span class="hlt">pointing</span> system that is applicable for a variety of payloads is examined. The system employs a very soft interface coupled with inertial control torques which use reaction wheels or control moment gyros. The fundamental stability and disturbance rejection characteristics of simple gimbal <span class="hlt">pointing</span> systems and the soft mounted inertially reacting concept are evaluated and compared. It is observed that in simple and two-stage gimbal systems there is dynamic interaction with the basebody and these types of systems are not applicable for a Space Station/Space Platform environment in which system dynamics are uncertain; however, the soft mounted inertially reacting concept minimizes the dynamic interaction with the basebody and retains stability. It is concluded that the soft mounted inertially reacting concept has the <span class="hlt">pointing</span> accuracy and disturbance isolation of a free flying spacecraft while still obtaining power, communication, orbit maintenance, and servicing from a basebody.</p> <div class="credits"> <p class="dwt_author">Sirlin, S. W.; Laskin, R. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">75</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20030025764&hterms=precision+pointing&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">Pointing</span> for the Laser Interferometry Space Antenna Mission</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The Laser Interferometer Space Antenna (LISA) mission is a planned NASA-ESA gravitational wave detector consisting of three spacecraft in heliocentric orbit. Lasers are used to measure distance fluctuations between proof masses aboard each spacecraft to the picometer level over a 5 million kilometer separation. Each spacecraft and its two laser transmit/receive telescopes must be held stable in <span class="hlt">pointing</span> to less than 8 nanoradians per root Hertz in the frequency band 0.1-100 mHz. The <span class="hlt">pointing</span> error is sensed in the received beam and the spacecraft attitude is controlled with a set of micro-Newton thrusters. Requirements, sensors, actuators, control design, and simulations are described.</p> <div class="credits"> <p class="dwt_author">Hyde, T. Tupper; Bauer, Frank H. (Technical Monitor); Maghami, P. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">76</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19800067769&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">A <span class="hlt">precision</span> <span class="hlt">pointing</span> system for Shuttle experiment payloads</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">This paper describes the Annular Suspension and <span class="hlt">Pointing</span> System (ASPS) being developed to support NASA Shuttle payloads in the 1980s. The ASPS employs a unique magnetic suspension system to isolate Shuttle payloads from Orbiter disturbances and provide vernier control of the payload's attitude, thereby allowing extremely accurate and stable <span class="hlt">pointing</span>. A description of the system design, configurations, and performance goals is given. Component and system development testing of the full-size ASPS Engineering Development Model is described, and hardware photographs and test configurations are presented.</p> <div class="credits"> <p class="dwt_author">Van Riper, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">77</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/2198586"> <span id="translatedtitle">A Cost Effective Pipelined Divider for Double <span class="hlt">Precision</span> Floating <span class="hlt">Point</span> Number</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The growth of high-performance application in computer graphics, signal processing and scientific computing is a key driver for high performance, fixed latency, pipelined floating <span class="hlt">point</span> dividers. Solutions available in the literature use large lookup table for double <span class="hlt">precision</span> floating <span class="hlt">point</span> operations. In this paper, we propose a cost effective, fixed latency pipelined divider using modified Taylor-series expansion for double <span class="hlt">precision</span></p> <div class="credits"> <p class="dwt_author">Sandeep B. Singh; Jayanta Biswas; S. K. Nandy</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">78</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://search.asee.org/search/fetch?url=file%3A%2F%2Flocalhost%2FE%3A%2Fsearch%2Fconference%2F14%2FAC%25202007Full2861.pdf&index=conference_papers&space=129746797203605791716676178&type=application%2Fpdf&charset="> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">Positioning</span> and Vibration Measurement Using Intelligent Instrumentation and Simulation Tools</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">The objective of this research is to detail the development of a simple and unique instrumentation for <span class="hlt">precise</span> micro-measurement as well as vibration measurement in an integrated manufacturing set up that can be demonstrated in a student laboratory. Based on this we propose new research for a smaller embedded measurement unit. All machines have some amount of forced vibration. However, in some cases, this vibration may cause damage to the machinery. Understanding vibration in aerospace applications is critical for any system that will be exposed to vibrating motion. Previously, strain gauges and piezoelectric accelerometers have been adequate for measuring vibration. However due to the increased requirements in performance, these methods are slowly being replaced by laser-based <span class="hlt">precision</span> instruments. One of the main reasons for this transition is the fact that the equipment in these methods must be mounted on the surface of the object being measured which can result in increasing the mass and altering the frequency, mode shape of the vibrating object. Laser technology is a non-contact measuring method and provides the resolution needed to satisfy the changing requirements. In order to demonstrate <span class="hlt">precise</span> <span class="hlt">positioning</span> and motion control for creating and detecting vibrational movements, an experimental test bed was constructed. Software based simulation tools were used to control the <span class="hlt">positioning</span> system. For vibration monitoring, the vibrating surface was discretely sampled by individual laser pulses and recorded by the <span class="hlt">position</span> sensitive detector by the generation of pulses whose magnitudes are proportional to the instantaneous surface displacements. With a sufficiently high sampling rate, reconstruction of the vibration wave form is achieved by conducting peak detection of the resultant series of pulses. Vibration sensing by <span class="hlt">position</span> sensing detector and vibration sensing by interferometry were the two techniques that were experimented with the new micro-<span class="hlt">positioning</span> system. Three methods of micro-<span class="hlt">positioning</span> and measurement were experimented; a <span class="hlt">precision</span> encoder, an optical interferometer and an integrated vision system. Data was collected at successive <span class="hlt">points</span> along the translation stages. The results showed that the optical interferometer and the encoder produced the most accurate results. It was also observed that significantly higher peak optical power levels of the probe laser pulses lead to proportional enhancement in the <span class="hlt">position</span> sensitive detector response and remarkable improvement in detection sensitivity. >/br>This paper also outlines the results of the new approach in micro-<span class="hlt">positioning</span>, displacement creation and vibration sampling in high <span class="hlt">precision</span> machine tools. Additional results with the prediction of break-through detection in laser drilling manufacturing process has also been documented.</p> <div class="credits"> <p class="dwt_author">Eppes, Tom; Hill, Jonathan; Shetty, Devdas</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-10-29</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">79</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20030053387&hterms=precision+pointing&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">Pointing</span> for the Laser Interferometry Space Antenna Mission</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">This viewgraph presentation discusses requirements for control systems in the design and production of space-based telescopes. Specific topics covered include: <span class="hlt">pointing</span> control methods, wavefront control methods, vibration control methods and thermal control methods. Control systems on the Hubble Space Telescope and the James Webb Space Telescope are reviewed. Control system requirements for future space telescopes are also mentioned.</p> <div class="credits"> <p class="dwt_author">Hyde, T. Tupper; Bauer, Frank H. (Technical Monitor)</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">80</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19900044059&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">Multiloop Balanced Bridge Feedback in application to <span class="hlt">precision</span> <span class="hlt">pointing</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The Balanced Bridge Feedback technique is applied to the multiloop <span class="hlt">pointing</span> control problem. Using colocated torque and angular velocity sensors and high-order compensators, the motor loop is decoupled from the flexible plant, the feedback bandwidth is increased in the motor and plant loops, and the accuracy improved by orders of magnitude compared to the results achievable with conventional control techniques.</p> <div class="credits"> <p class="dwt_author">Lurie, B. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_3");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a style="font-weight: bold;">4</a> <a 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href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_6");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">81</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20030053081&hterms=precision+pointing&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">Pointing</span> for the Laser Interferometer Space Antenna (LISA) Mission</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The Laser Interferometer Space Antenna (LISA) mission is a planned NASA-ESA gravity wave detector consisting of three spacecraft in heliocentric orbit. Lasers are used to measure distance fluctuations between the proof masses aboard the spacecraft to the picometer level over the 5 million kilometer spacing. Each spacecraft and it's two laser transmit/receive telescopes must be held stable in <span class="hlt">pointing</span> to less than 8 nanoradians per root Hertz in the frequency band 0.1 mHz to 0.1 Hz. This is accomplished by sensing the <span class="hlt">pointing</span> error in the received beam and controlling the spacecraft attitude with a set of micronewton thrusters. Requirements, sensors, actuators, control design, and simulations are described in this paper.</p> <div class="credits"> <p class="dwt_author">Bauer, Frank H. (Technical Monitor); Hyde, T. Tupper; Maghami, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">82</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/772047"> <span id="translatedtitle"><span class="hlt">Pointing</span> Control System for a High <span class="hlt">Precision</span> Flight Telescope</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A <span class="hlt">pointing</span> control system is developed and tested for a flying gimbaled telescope. The two-axis <span class="hlt">pointing</span> system is capable of sub-microradian <span class="hlt">pointing</span> stability and high accuracy in the presence of large host vehicle jitter. The telescope also has high agility--it is capable of a 50-degree retarget (in both axes simultaneously) in less than 2 seconds. To achieve the design specifications, high-accuracy, high-resolution, two-speed resolvers were used, resulting in gimbal-angle measurements stable to 1.5 microradians. In addition, on-axis inertial angle displacement sensors were mounted on the telescope to provide host-vehicle jitter cancellation. The inertial angle sensors are accurate to about 100 nanoradians, but do not measure low frequency displacements below 2 Hz. The gimbal command signal includes host-vehicle attitude information, which is band-limited. This provides jitter data below 20 Hz, but includes a variable latency between 15 and 25 milliseconds. One of the most challenging aspects of this design was to combine the inertial-angle-sensor data with the less perfect information in the command signal to achieve maximum jitter reduction. The optimum blending of these two signals, along with the feedback compensation were designed using Quantitative Feedback Theory.</p> <div class="credits"> <p class="dwt_author">BENTLEY,ANTHONY E.; WILCOXEN,JEFFREY LEE</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">83</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014SPIE.9143E..47M"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">pointing</span> control for SPICA: risk mitigation phase study</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">SPICA (Space Infrared Telescope for Cosmology and Astrophysics) is an astronomical mission optimized for mid- and far-infrared astronomy with a 3-m class telescope which is cryogenically cooled to be less than 6 K. The SPICA mechanical cooling system is indispensable for the mission but, generates micro-vibrations which could affect to the <span class="hlt">pointing</span> stability performances. Activities to be undertaken during a risk mitigation phase (RMP) include consolidation of micro-vibration control design for the satellite, as well as a number of breadboarding activities centered on technologies that are critical to the success of the mission. This paper presents the RMP activity results on the microvibration control design.</p> <div class="credits"> <p class="dwt_author">Mitani, Shinji; Kawakatsu, Yasuhiro; Sakai, Shin-ichiro; Murakami, Naomi; Yamawaki, Toshihiko; Mizutani, Tadahito; Komatsu, Keiji; Kataza, Hirokazu; Enya, Keigo; Nakagawa, Takao</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">84</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19880062984&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">A <span class="hlt">precision</span> <span class="hlt">pointing</span> system for space telescope class optical trackers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">This paper reports on the results of a study effort whose main objective was to develop a conceptual design for a space based, large-payload (3000 kg) <span class="hlt">pointing</span> system capable of both rapid slew maneuvers (0.35 rad/sec-squared) and very stable tracking (1 microrad, 1 sigma, each axis). The key features of the resulting solution are: (1) cross elevation over elevation gimbal system, (2) closed cross elevation gimbal ring, (3) graphite-epoxy structure, (4) two-motor reactionless joint torquers, (5) payload mounted vernier reaction wheel, and (6) gyrostabilized model following control system.</p> <div class="credits"> <p class="dwt_author">Sevaston, George E.; Schier, J. Alan; Iskenderian, Theodore C.; Lin, Yu-Hwan; Satter, Celeste M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">85</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014DPS....4642201F"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">Pointing</span> Reconstruction and Geometric Metadata Generation for Cassini Images</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Analysis of optical remote sensing (ORS) data from the Cassini spacecraft is a complicated and labor-intensive process. First, small errors in Cassini’s <span class="hlt">pointing</span> information (up to ~40 pixels for the Imaging Science Subsystem Narrow Angle Camera) must be corrected so that the line of sight vector for each pixel is known. This process involves matching the image contents with known features such as stars, ring edges, or moon limbs. Second, metadata for each pixel must be computed. Depending on the object under observation, this metadata may include lighting geometry, moon or planet latitude and longitude, and/or ring radius and longitude. Both steps require mastering the SPICE toolkit, a highly capable piece of software with a steep learning curve. Only after these steps are completed can the actual scientific investigation begin.We are embarking on a three-year project to perform these steps for all 300,000+ Cassini ISS images as well as images taken by the VIMS, UVIS, and CIRS instruments. The result will be a series of SPICE kernels that include accurate <span class="hlt">pointing</span> information and a series of backplanes that include precomputed metadata for each pixel. All data will be made public through the PDS Rings Node (http://www.pds-rings.seti.org). We expect this project to dramatically decrease the time required for scientists to analyze Cassini data. In this poster we discuss the project, our current status, and our plans for the next three years.</p> <div class="credits"> <p class="dwt_author">French, Robert S.; Showalter, Mark R.; Gordon, Mitchell K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">86</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AdSpR..51.1008L"> <span id="translatedtitle">The GFZ real-time GNSS <span class="hlt">precise</span> <span class="hlt">positioning</span> service system and its adaption for COMPASS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Motivated by the IGS real-time Pilot Project, GFZ has been developing its own real-time <span class="hlt">precise</span> <span class="hlt">positioning</span> service for various applications. An operational system at GFZ is now broadcasting real-time orbits, clocks, global ionospheric model, uncalibrated phase delays and regional atmospheric corrections for standard PPP, PPP with ambiguity fixing, single-frequency PPP and regional augmented PPP. To avoid developing various algorithms for different applications, we proposed a uniform algorithm and implemented it into our real-time software. In the new processing scheme, we employed un-differenced raw observations with atmospheric delays as parameters, which are properly constrained by real-time derived global ionospheric model or regional atmospheric corrections and by the empirical characteristics of the atmospheric delay variation in time and space. The <span class="hlt">positioning</span> performance in terms of convergence time and ambiguity fixing depends mainly on the quality of the received atmospheric information and the spatial and temporal constraints. The un-differenced raw observation model can not only integrate PPP and NRTK into a seamless <span class="hlt">positioning</span> service, but also syncretize these two techniques into a unique model and algorithm. Furthermore, it is suitable for both dual-frequency and sing-frequency receivers. Based on the real-time data streams from IGS, EUREF and SAPOS reference networks, we can provide services of global <span class="hlt">precise</span> <span class="hlt">point</span> <span class="hlt">positioning</span> (PPP) with 5-10 cm accuracy, PPP with ambiguity-fixing of 2-5 cm accuracy, PPP using single-frequency receiver with accuracy of better than 50 cm and PPP with regional augmentation for instantaneous ambiguity resolution of 1-3 cm accuracy. We adapted the system for current COMPASS to provide PPP service. COMPASS observations from a regional network of nine stations are used for <span class="hlt">precise</span> orbit determination and clock estimation in simulated real-time mode, the orbit and clock products are applied for real-time <span class="hlt">precise</span> <span class="hlt">point</span> <span class="hlt">positioning</span>. The simulated real-time PPP service confirms that real-time <span class="hlt">positioning</span> services of accuracy at dm-level and even cm-level is achievable with COMPASS only.</p> <div class="credits"> <p class="dwt_author">Li, Xingxing; Ge, Maorong; Zhang, Hongping; Nischan, Thomas; Wickert, Jens</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">87</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1987JSP....47..959F"> <span id="translatedtitle"><span class="hlt">Point</span> processes and the <span class="hlt">position</span> distribution of infinite boson systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">It is shown that to each locally normal state of a boson system one can associate a <span class="hlt">point</span> process that can be interpreted as the <span class="hlt">position</span> distribution of the state. The <span class="hlt">point</span> process contains all information one can get by <span class="hlt">position</span> measurements and is determined by the latter. On the other hand, to each so-called ?c-<span class="hlt">point</span> process Q we relate a locally normal state with <span class="hlt">position</span> distribution Q.</p> <div class="credits"> <p class="dwt_author">Fichtner, K.-H.; Freudenberg, W.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">88</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19890044098&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">Control-structure interaction in <span class="hlt">precision</span> <span class="hlt">pointing</span> servo loops</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The control-structure interaction problem is addressed via stability analysis of a generic linear servo loop model. With the plant described by the rigid body mode and a single elastic mode, structural flexibility is categorized into one of three types: (1) appendage, (2) in-the-loop minimum phase, and (3) in-the-loop nonminimum phase. Closing the loop with proportional-derivative (PD) control action and introducing sensor roll-off dynamics in the feedback path, stability conditions are obtained. Trade studies are conducted with modal frequency, modal participation, modal damping, loop bandwidth, and sensor bandwidth treated as free parameters. Results indicate that appendage modes are most likely to produce instability if they are near the sensor rolloff, whereas in-the-loop modes are most dangerous near the loop bandwidth. The main goal of this paper is to provide a fundamental understanding of the control-structure interaction problem so that it may benefit the design of complex spacecraft and <span class="hlt">pointing</span> system servo loops. In this framework, the JPL Pathfinder gimbal pointer is considered as an example.</p> <div class="credits"> <p class="dwt_author">Spanos, John T.</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">89</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dspace.mit.edu/handle/1721.1/90732"> <span id="translatedtitle">High-<span class="hlt">precision</span> <span class="hlt">pointing</span> and attitude estimation and control algorithms for hardware-constrained spacecraft</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">The overarching objective of this thesis is to develop algorithms for high-<span class="hlt">precision</span> <span class="hlt">pointing</span> and attitude estimation and control on hardware-constrained spacecraft. This includes small spacecraft, where tight mass, volume, ...</p> <div class="credits"> <p class="dwt_author">Pong, Christopher Masaru</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">90</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/39263539"> <span id="translatedtitle">Performing Floating-<span class="hlt">Point</span> Accumulation on a Modern FPGA in Single and Double <span class="hlt">Precision</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this paper, we discuss the feasibility of a floating-<span class="hlt">point</span> accumulator (FPACC) on modern high-end FPGA devices. We explore different implementation scenarios and propose new FPACC architectures for both single and double <span class="hlt">precision</span> floating-<span class="hlt">point</span> addends. The proposed strategies can be easily adapted to the implement a multiply-accumulator (FPMAC), with one or two rounding stages, in both single and double <span class="hlt">precision</span></p> <div class="credits"> <p class="dwt_author">Tarek Ould Bachir; Jean-Pierre David</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">91</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://lib.semi.ac.cn:8080/tsh/dzzy/wsqk/spie/vol6624/662418.pdf"> <span id="translatedtitle">Closed loop high <span class="hlt">precision</span> <span class="hlt">position</span> control system with optical scale</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">With the developments of science of art, there are more and more demands on the high resolution control of <span class="hlt">position</span> of object to be controlled, such as lathe, product line, elements in the optical resonant cavity, telescope, and so on. As one device with high resolution, the optical scale has more and more utility within the industrial and civil applications.</p> <div class="credits"> <p class="dwt_author">Cheng-liang Ge; Yuan Liao; Zhong-wu He; Zhong-xiang Luo; Zhi-wei Huang; Min Wan; Xiao-yang Hu; Guo-bin Fan; Zheng Liang</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">92</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17820661"> <span id="translatedtitle">Global <span class="hlt">positioning</span> system measurements for crustal deformation: <span class="hlt">precision</span> and accuracy.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Analysis of 27 repeated observations of Global <span class="hlt">Positioning</span> System (GPS) <span class="hlt">position</span>-difference vectors, up to 11 kilometers in length, indicates that the standard deviation of the measurements is 4 millimeters for the north component, 6 millimeters for the east component, and 10 to 20 millimeters for the vertical component. The uncertainty grows slowly with increasing vector length. At 225 kilometers, the standard deviation of the measurement is 6, 11, and 40 millimeters for the north, east, and up components, respectively. Measurements with GPS and Geodolite, an electromagnetic distance-measuring system, over distances of 10 to 40 kilometers agree within 0.2 part per million. Measurements with GPS and very long baseline interferometry of the 225-kilometer vector agree within 0.05 part per million. PMID:17820661</p> <div class="credits"> <p class="dwt_author">Prescott, W H; Davis, J L; Svarc, J L</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-06-16</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">93</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70015072"> <span id="translatedtitle">Global <span class="hlt">positioning</span> system measurements for crustal deformation: <span class="hlt">Precision</span> and accuracy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Analysis of 27 repeated observations of Global <span class="hlt">Positioning</span> System (GPS) <span class="hlt">position</span>-difference vectors, up to 11 kilometers in length, indicates that the standard deviation of the measurements is 4 millimeters for the north component, 6 millimeters for the east component, and 10 to 20 millimeters for the vertical component. The uncertainty grows slowly with increasing vector length. At 225 kilometers, the standard deviation of the measurement is 6, 11, and 40 millimeters for the north, east, and up components, respectively. Measurements with GPS and Geodolite, an electromagnetic distance-measuring system, over distances of 10 to 40 kilometers agree within 0.2 part per million. Measurements with GPS and very long baseline interferometry of the 225-kilometer vector agree within 0.05 part per million.</p> <div class="credits"> <p class="dwt_author">Prescott, W. H.; Davis, J. L.; Svarc, J. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">94</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/549060"> <span id="translatedtitle">High <span class="hlt">precision</span> global <span class="hlt">positioning</span> system for mining applications</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The author discusses today`s satellite technology that has lead to the development of a system that will increase safety and production in surface mining. The Department of Defense is maintaining a satellite system made up of 24 NavStar satellites that allow the use of their frequencies to <span class="hlt">position</span> equipment anywhere on Earth. The previous satellite system was called the Transit system or Sat-Nav. It consisted of low-orbit satellites (not many up there) that ground-based receivers needed three days of logged data to process sub-meter accuracy <span class="hlt">positions</span>. With the NavStar network of satellites, centimeter accuracy can be achieved within just a few minutes. Changes to the way one used to survey in the mining industry are being replaced with the Global <span class="hlt">Positioning</span> System. It has proven to be a system that is more accurate and after the typical learning curve that is required by any new system, will lead to higher productivity; hence, financial rewards are in the immediate future.</p> <div class="credits"> <p class="dwt_author">O`Grady, M. [Trimble Navigation, Ltd., Elgin, IL (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">95</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008IJTIA.128..742Y"> <span id="translatedtitle"><span class="hlt">Precise</span> Disturbance Modeling for Improvement of <span class="hlt">Positioning</span> Performance</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This paper presents a modeling methodology for unknown disturbances in mechatronics systems, based on a disturbance estimation using an iterative learning process. In the disturbance modeling, the nonlinear friction is especially handled as the disturbance in mechanisms, which mainly deteriorates the trajectory control performance. The friction can be mathematically modeled by using the learned estimation data, as a function of displacement, velocity, acceleration, and jerk of the actuator. This model has a distinguished feature that the friction compensation can be achieved with a generalization capability for different conditions. The proposed <span class="hlt">positioning</span> control approach with the disturbance modeling and compensation has been verified by experiments using a table drive system on machine stand.</p> <div class="credits"> <p class="dwt_author">Yamamoto, Masafumi; Iwasaki, Makoto; Ito, Kazuaki; Matsui, Nobuyuki</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">96</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20060036042&hterms=precision+pointing&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">Adaptive Neural Star Tracker Calibration for <span class="hlt">Precision</span> Spacecraft <span class="hlt">Pointing</span> and Tracking</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The Star Tracker is an essential sensor for <span class="hlt">precision</span> <span class="hlt">pointing</span> and tracking in most 3-axis stabilized spacecraft. In the interest (of) improving <span class="hlt">pointing</span> performance by taking advantage of dramatic increases in flight computer power and memory anticipated over the next decade, this paper investigates the use of a neural net for adaptive in-flight calibration of the Star Tracker.</p> <div class="credits"> <p class="dwt_author">Bayard, David S.</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">97</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19950029651&hterms=global+positioning+system&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2522global%2Bpositioning%2Bsystem%2522"> <span id="translatedtitle"><span class="hlt">Precise</span> mean sea level measurements using the Global <span class="hlt">Positioning</span> System</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">This paper describes the results of a sea level measurement test conducted off La Jolla, California, in November of 1991. The purpose of this test was to determine accurate sea level measurements using a Global <span class="hlt">Positioning</span> System (GPS) equipped buoy. These measurements were intended to be used as the sea level component for calibration of the ERS 1 satellite altimeter. Measurements were collected on November 25 and 28 when the ERS 1 satellite overflew the calibration area. Two different types of buoys were used. A waverider design was used on November 25 and a spar design on November 28. This provided the opportunity to examine how dynamic effects of the measurement platform might affect the sea level accuracy. The two buoys were deployed at locations approximately 1.2 km apart and about 15 km west of a reference GPS receiver located on the rooftop of the Institute of Geophysics and Planetary Physics at the Scripps Institute of Oceanography. GPS solutions were computed for 45 minutes on each day and used to produce two sea level time series. An estimate of the mean sea level at both locations was computed by subtracting tide gage data collected at the Scripps Pier from the GPS-determined sea level measurements and then filtering out the high-frequency components due to waves and buoy dynamics. In both cases the GPS estimate differed from Rapp's mean altimetric surface by 0.06 m. Thus, the gradient in the GPS measurements matched the gradient in Rapp's surface. These results suggest that accurate sea level can be determined using GPS on widely differing platforms as long as care is taken to determine the height of the GPS antenna phase center above water level. Application areas include measurement of absolute sea level, of temporal variations in sea level, and of sea level gradients (dominantly the geoid). Specific applications would include ocean altimeter calibration, monitoring of sea level in remote regions, and regional experiments requiring spatial and temporal resolution higher than that available from altimeter data.</p> <div class="credits"> <p class="dwt_author">Kelecy, Thomas M.; Born, George H.; Parke, Michael E.; Rocken, Christian</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">98</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007SPIE.6722E..0FX"> <span id="translatedtitle">Research on key techniques of nanometer scale macro-micro dual-drive <span class="hlt">precision</span> <span class="hlt">positioning</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">With the development of science and technology, high <span class="hlt">precision</span> of <span class="hlt">positioning</span> platform is needed in many areas, for example, cell fusing in biology and <span class="hlt">precision</span> surgery in medical area. In such areas, both high efficiency and high <span class="hlt">precision</span> are needed in some cases, for example, semiconductor processing equipment, super <span class="hlt">precision</span> lathe etc. In a word, <span class="hlt">precision</span> <span class="hlt">positioning</span> platform becomes an important tool in exploring microscope world. <span class="hlt">Precision</span> <span class="hlt">positioning</span> platform is a key element in microscope operation. Macro/micro dual-drive <span class="hlt">precision</span> <span class="hlt">positioning</span> is a key technique in high-efficiency high-<span class="hlt">precision</span> area. By such techniques, large distance and high <span class="hlt">precision</span> can get. In order to realize nanometer scale macro/micro dual-drive <span class="hlt">precision</span> <span class="hlt">positioning</span> there are some key problems. First, system structure of macro/micro combination <span class="hlt">precision</span> <span class="hlt">positioning</span> platform is worthy to work on. Another key work is realization method of micrometer scale macroscope motion and nanometer scale microscope motion. The third is mechanics, drive, detection and control techniques in nanometer scale <span class="hlt">positioning</span> of piezoelectric ceramics drive, in which realization of nanometer scale microscope <span class="hlt">positioning</span> and micro drive is important by solving hysteresis, creep deformation and non-linearity in piezoelectric ceramics driving. To solve hysteresis problem, instead of traditional Preisach algorithm, a new type hysteresis model with simple computation and identification is needed. The inverse model is also easily to get. So we can present new control method to solve hysteresis and creep deformation problem based on this inverse model. Another way, hysteresis and creep deformation problem exist in traditional voltage-feedback power source for piezoelectric ceramics. To solve this problem, a new type current feedback power source for piezoelectric ceramics is presented. In the end, a macro-micro dual-drive super <span class="hlt">precision</span> <span class="hlt">positioning</span> mechanism is presented. Combining macro with micro actuator, a system with large workspace and high resolution of motion is presented. The linear direct-drive motor is used in the macroscope motion and high frequency PZT-driven microscope stage is embedded in the motor and compensates the <span class="hlt">position</span> error. A high-resolution linear encoder is integrated into the closed-loop feedback, which is used to measure the <span class="hlt">position</span> of the end-effect in microscope scale.</p> <div class="credits"> <p class="dwt_author">Xie, Xiaohui; Du, Ruxu</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">99</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/905268"> <span id="translatedtitle">Fast, Accurate Static Analysis for Fixed-<span class="hlt">Point</span> Finite-<span class="hlt">Precision</span> Effects in DSP Designs</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Translating digital signal processing (DSP) software intoits finite-<span class="hlt">precision</span> hardware implementation is often a time-consumingtask. We describe a new static analysis techniquethat can accurately analyze finite-<span class="hlt">precision</span> effects arisingfrom fixed-<span class="hlt">point</span> implementations of DSP algorithms.The technique is based on recent interval representation methodsfrom affine arithmetic, and the use of new probabilisticbounds. The resulting numerical error estimates are comparableto detailed statistical simulation, but achieve</p> <div class="credits"> <p class="dwt_author">Claire Fang Fang; Rob A. Rutenbar; Tsuhan Chen</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">100</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/53578213"> <span id="translatedtitle"><span class="hlt">Precise</span> <span class="hlt">positioning</span> control with double feedback loop for ultralarge scale integrated manufacturing machine</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This article presents a new <span class="hlt">positioning</span> control system for ultralarge scale integrated (ULSI) circuit manufacturing machines. Both accuracy and high speed are required in the <span class="hlt">positioning</span> control of ULSI manufacturing. Two major problems exist in the <span class="hlt">precise</span> <span class="hlt">positioning</span> control: mechanical resonance and steady state error induced by solid friction. The proposed control system utilizes H2 control to compensate for the</p> <div class="credits"> <p class="dwt_author">Yoshihiko Takahashi; Hideyuki Takahashi</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_4");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a 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<img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">101</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/56902307"> <span id="translatedtitle"><span class="hlt">Precise</span> <span class="hlt">positioning</span> using gps for category-III aircraft operations using smoothed pseudorange measurements</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Currently, standard single frequency Global <span class="hlt">Positioning</span> System (GPS) receivers provide a <span class="hlt">positioning</span> accuracy of approximately 4--20 m. This <span class="hlt">precision</span> can be further enhanced with dual frequency receivers which are able to provide accuracy around 1--12 m. However, these errors are quite large when it comes to safety of life applications such as aircraft landings. Differential GPS (D-GPS) allows for <span class="hlt">precise</span></p> <div class="credits"> <p class="dwt_author">S. Agarwal; H. B. Hablani</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">102</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3638640"> <span id="translatedtitle">Obtaining Glenoid <span class="hlt">Positioning</span> Data from Scapular Palpable <span class="hlt">Points</span> In Vitro</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Both clinical and biomechanical problems affecting the shoulder joint suggest that investigators should study force transmission into and out from the scapula. To analyze force transmission between the humeral head and the glenoid, one must know the <span class="hlt">position</span> of the glenoid. Studies have analyzed the <span class="hlt">position</span> of the scapula from the <span class="hlt">positions</span> of three palpable <span class="hlt">points</span>, but the <span class="hlt">position</span> of the glenoid relative to three palpable <span class="hlt">points</span> has not been studied. Dry scapulae (N = 13) were subjected to X-rays and a critical angle, ? (which relates the plane determined by the three palpable <span class="hlt">points</span> on the scapula to a plane containing the glenoid center and the first two palpable <span class="hlt">points</span>) was calculated. The mean value for ? was 28.5 ± 5.60 degrees. The obtained ? allows us to determine the <span class="hlt">position</span> of the glenoid from three palpable <span class="hlt">points</span>. This information could be used in calculation of forces across the shoulder joint, which in turn would allow optimizing the choice of strengthening exercises. PMID:23653863</p> <div class="credits"> <p class="dwt_author">Trafimow, Jordan H.; Aruin, Alexander S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">103</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/39212054"> <span id="translatedtitle">Multipliers for floating-<span class="hlt">point</span> double <span class="hlt">precision</span> and beyond on FPGAs</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The implementation of high-<span class="hlt">precision</span> floating-<span class="hlt">point</span> applications on reconfigurable hardware requires large multipliers. Full multipliers are the core of floating-<span class="hlt">point</span> multipliers. Truncated multipliers, trading resources for a well-controlled accuracy degradation, are useful building blocks in situations where a full multiplier is not needed. This work studies the automated generation of such multipliers using the embedded multipliers and adders present in the</p> <div class="credits"> <p class="dwt_author">Sebastian Banescu; Florent de Dinechin; Bogdan Pasca; Radu Tudoran</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">104</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/905535"> <span id="translatedtitle">The formal verification of a pipelined double-<span class="hlt">precision</span> IEEE floating-<span class="hlt">point</span> multiplier</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Floating-<span class="hlt">point</span> circuits are notoriously difficult to design and verify. For verification, simulation barely offers adequate coverage, conventional model-checking techniques are infeasible, and theorem-proving based verification is not sufficiently mature. In this paper we present the formal verification of a radix-eight, pipelined, IEEE double-<span class="hlt">precision</span> floating-<span class="hlt">point</span> multiplier. The verification was carried out using a mixture of model-checking and theorem-proving techniques in the</p> <div class="credits"> <p class="dwt_author">Mark D. Aagaard; Carl-Johan H. Seger</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">105</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011SPIE.8042E..0AS"> <span id="translatedtitle"><span class="hlt">Precise</span> <span class="hlt">positioning</span> surveillance in 3-D using night-vision stereoscopic photogrammetry</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A 3-D imaging technique is presented which pairs high-resolution night-vision cameras with GPS to increase the capabilities of passive imaging surveillance. Camera models and GPS are used to derive a registered <span class="hlt">point</span> cloud from multiple night-vision images. These <span class="hlt">point</span> clouds are used to generate 3-D scene models and extract real-world <span class="hlt">positions</span> of mission critical objects. Analysis shows accuracies rivaling laser scanning even in near-total darkness. The technique has been tested on stereoscopic 3-D video collections as well. Because this technique does not rely on active laser emissions it is more portable, less complex, less costly, and less detectable than laser scanning. This study investigates close-range photogrammetry under night-vision lighting conditions using practical use-case examples of terrain modeling, covert facility surveillance, and stand-off facial recognition. The examples serve as the context for discussion of a standard processing workflow. Results include completed, geo-referenced 3-D models, assessments of related accuracy and <span class="hlt">precision</span>, and a discussion of future activities.</p> <div class="credits"> <p class="dwt_author">Schwartz, Jason M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">106</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19860042214&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">Design of a <span class="hlt">precision</span> <span class="hlt">pointing</span> control system for the space infrared telescope facility</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">This paper describes the design of a <span class="hlt">precision</span> <span class="hlt">pointing</span> control system for the Space Infrared Telescope Facility (SIRTF). Mission requirements and their impact on control system design are discussed along with the original features of the control strategy. Simulation of the total system is described, and the most significant results are presented.</p> <div class="credits"> <p class="dwt_author">Sridhar, B.; Aubrun, J.-N.; Lorell, K. R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">107</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19730022872&hterms=selectivity+linearity+accuracy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dselectivity%2Blinearity%2Baccuracy"> <span id="translatedtitle">Study of <span class="hlt">precise</span> <span class="hlt">positioning</span> at L-band using communications satellites</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The L-band <span class="hlt">positioning</span> experiment is reported which encompassed experiment design, experimentation, and data reduction and analysis. In the experiment the ATS-5 synchronous satellite L-band transponder was used in conjunction with the modified ALPHA 2 navigation receivers to demonstrate the technical capability of <span class="hlt">precision</span> <span class="hlt">position</span> fixing for oceanographic purposes. The feasibility of using relative ranging techniques implemented by two identical receiving systems, properly calibrated, to determine a line of <span class="hlt">position</span> accurately on the surface of the earth was shown. The program demonstrated the level of resolution, repeatibility, <span class="hlt">precision</span>, and accuracy of existing modest-cost effective navigation equipment. The experiment configuration and data reduction techniques were developed in parallel with the hardware modification tasks. Test results verify the ability of a satellite-based system to satisfy the requirements of <span class="hlt">precision</span> <span class="hlt">position</span> fixing.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1971-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">108</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19750002085&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">Pointing</span> Control System (PPCS) system design and analysis. [for gimbaled experiment platforms</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The <span class="hlt">precision</span> <span class="hlt">pointing</span> control system (PPCS) is an integrated system for <span class="hlt">precision</span> attitude determination and orientation of gimbaled experiment platforms. The PPCS concept configures the system to perform orientation of up to six independent gimbaled experiment platforms to design goal accuracy of 0.001 degrees, and to operate in conjunction with a three-axis stabilized earth-oriented spacecraft in orbits ranging from low altitude (200-2500 n.m., sun synchronous) to 24 hour geosynchronous, with a design goal life of 3 to 5 years. The system comprises two complementary functions: (1) attitude determination where the attitude of a defined set of body-fixed reference axes is determined relative to a known set of reference axes fixed in inertial space; and (2) <span class="hlt">pointing</span> control where gimbal orientation is controlled, open-loop (without use of payload error/feedback) with respect to a defined set of body-fixed reference axes to produce <span class="hlt">pointing</span> to a desired target.</p> <div class="credits"> <p class="dwt_author">Frew, A. M.; Eisenhut, D. F.; Farrenkopf, R. L.; Gates, R. F.; Iwens, R. P.; Kirby, D. K.; Mann, R. J.; Spencer, D. J.; Tsou, H. S.; Zaremba, J. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1972-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">109</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..16.1741A"> <span id="translatedtitle">Employing Tropospheric Numerical Weather Prediction Model for High-<span class="hlt">Precision</span> GNSS <span class="hlt">Positioning</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In the past few years is increasing the necessity of realizing high accuracy <span class="hlt">positioning</span>. In this sense, the spatial technologies have being widely used. The GNSS (Global Navigation Satellite System) has revolutionized the geodetic <span class="hlt">positioning</span> activities. Among the existent methods one can emphasize the <span class="hlt">Precise</span> <span class="hlt">Point</span> <span class="hlt">Positioning</span> (PPP) and network-based <span class="hlt">positioning</span>. But, to get high accuracy employing these methods, mainly in real time, is indispensable to realize the atmospheric modeling (ionosphere and troposphere) accordingly. Related to troposphere, there are the empirical models (for example Saastamoinen and Hopfield). But when highly accuracy results (error of few centimeters) are desired, maybe these models are not appropriated to the Brazilian reality. In order to minimize this limitation arises the NWP (Numerical Weather Prediction) models. In Brazil the CPTEC/INPE (Center for Weather Prediction and Climate Studies / Brazilian Institute for Spatial Researches) provides a regional NWP model, currently used to produce Zenithal Tropospheric Delay (ZTD) predictions (http://satelite.cptec.inpe.br/zenital/). The actual version, called eta15km model, has a spatial resolution of 15 km and temporal resolution of 3 hours. In this paper the main goal is to accomplish experiments and analysis concerning the use of troposphere NWP model (eta15km model) in PPP and network-based <span class="hlt">positioning</span>. Concerning PPP it was used data from dozens of stations over the Brazilian territory, including Amazon forest. The results obtained with NWP model were compared with Hopfield one. NWP model presented the best results in all experiments. Related to network-based <span class="hlt">positioning</span> it was used data from GNSS/SP Network in São Paulo State, Brazil. This network presents the best configuration in the country to realize this kind of <span class="hlt">positioning</span>. Actually the network is composed by twenty stations (http://www.fct.unesp.br/#!/pesquisa/grupos-de-estudo-e-pesquisa/gege//gnss-sp-network2789/). The results obtained employing NWP model also were compared to Hopfield one, and the results were very interesting. The theoretical concepts, experiments, results and analysis will be presented in this paper.</p> <div class="credits"> <p class="dwt_author">Alves, Daniele; Gouveia, Tayna; Abreu, Pedro; Magário, Jackes</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">110</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003GGAS...65.....B"> <span id="translatedtitle">Efficient methods for determining <span class="hlt">precise</span> orbits of low Earth orbiters using the Global <span class="hlt">Positioning</span> System</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The main part of this work dealt with the development and evaluation of efficient methods for <span class="hlt">precise</span> orbit determination of LEOs. A kinematic approach using GPS zero-difference observations was developed (program LEOKIN) and a procedure for generation of dynamic and reduced-dynamic orbits was presented (program SATORB). The procedures have been tested using long GPS data series gathered by two LEO satellites, namely CHAMP and SAC-C. An external comparison was available for the time interval of the eleven days of the IGS CHAMP test campaign (May 20 to 30, 2001). The orbit solution generated at the Technical University of Munich (TUM), Germany, using the Bernese GPS Software was used for this purpose. The TUM-solution is believed to be one of the best solutions contributing to the IGS test campaign. Comparisons with this solution showed that both our best kinematic trajectory and a post-fit reduced-dynamic orbit based on this kinematic solution compare within an RMS error per coordinate (of a Helmert transformation) of about 10 cm with the TUM-solutions. This indicates that LEO orbits with a quality of about 10 cm result from our analyses. The goal of developing efficient methods for <span class="hlt">precise</span> orbit determination of LEOs is therefore achieved with the zero-difference kinematic <span class="hlt">point</span> <span class="hlt">positioning</span> procedure in LEOKIN and the program SATORB to generate reduced-dynamic orbits. It is worth mentioning that the procedure, when using only code observations as input, results in reduced-dynamic orbits with a qualitiy of already 30 cm RMS.</p> <div class="credits"> <p class="dwt_author">Bock, Heike</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">111</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014OptLE..62...31L"> <span id="translatedtitle">A novel orientation and <span class="hlt">position</span> measuring system for large & medium scale <span class="hlt">precision</span> assembly</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In the field of <span class="hlt">precision</span> assembly of large & medium scale, the orientation and <span class="hlt">position</span> measurement system is quite demanding. In this paper a novel measuring system, consisting of four motorized stages, a laser rangefinder, an autocollimator and a camera is proposed to assist <span class="hlt">precision</span> assembly. Through the design of coaxial optical system, the autocollimator is integrated with a laser rangefinder into a collimation rangefinder, which is used for measuring orientation and <span class="hlt">position</span> synchronously. The laser spot is adopted to guide autocollimation over a large space and assist the camera in finding collimated measurand. The mathematical models and practical calibration methods for measurement are elaborated. The preliminary experimental results agree with the methods currently being used for orientation and <span class="hlt">position</span> measurement. The measuring method provides an alternative choice for the metrology in <span class="hlt">precision</span> assembly.</p> <div class="credits"> <p class="dwt_author">Li, Yuhe; Qiu, Yongrong; Chen, Yanxiang; Guan, Kaisen</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">112</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/16504410"> <span id="translatedtitle">Effect of fatigue on the <span class="hlt">precision</span> of a whole-body <span class="hlt">pointing</span> task.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We addressed the issue of the possible degradation of the aiming <span class="hlt">precision</span> of a whole-body <span class="hlt">pointing</span> task, when movement coordination is deranged by selective fatigue of the postural task component. The protocol involved continuous repetition (0.1 Hz frequency) of rapid whole-body <span class="hlt">pointing</span> trials toward a target located beyond arm length, starting from stance and requiring knee flexion. Six healthy human subjects repeated the trials until exhaustion. Such repetition led to electromyography signs of fatigue in rectus femoris (active in body lowering and raising), but not in deltoid (prime mover for arm reaching component). Rectus femoris fatigue affected the equilibrium control strategy, since the anteroposterior displacement of the center of foot pressure was reduced during the fatigued compared with the initial trials. Conversely, the <span class="hlt">precision</span> of the aiming movement was unaffected by the rectus femoris fatigue in spite of changes in finger trajectory. Trunk inclination at the end of whole-body <span class="hlt">pointing</span> task and hip and shoulder marker trajectories were unaffected by rectus femoris fatigue. Control experiments were made, whereby fatiguing repetitions of the postural component of the task were performed without finger <span class="hlt">pointing</span>, except in the first and last five complete whole-body <span class="hlt">pointing</span> trials. The results were not different from those of the main protocol, except for a transient change in finger trajectory in the very first trial after fatigue. The CNS takes into account the state of postural muscles' fatigue and the concurrently ensuing equilibrium constraints in order to appropriately modify whole-body <span class="hlt">pointing</span> strategy and keep <span class="hlt">pointing</span> <span class="hlt">precision</span> at the target. PMID:16504410</p> <div class="credits"> <p class="dwt_author">Schmid, M; Schieppati, M; Pozzo, T</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">113</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/860342"> <span id="translatedtitle">High-<span class="hlt">Precision</span> Floating-<span class="hlt">Point</span> Arithmetic in ScientificComputation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">At the present time, IEEE 64-bit floating-<span class="hlt">point</span> arithmetic is sufficiently accurate for most scientific applications. However, for a rapidly growing body of important scientific computing applications, a higher level of numeric <span class="hlt">precision</span> is required: some of these applications require roughly twice this level; others require four times; while still others require hundreds or more digits to obtain numerically meaningful results. Such calculations have been facilitated by new high-<span class="hlt">precision</span> software packages that include high-level language translation modules to minimize the conversion effort. These activities have yielded a number of interesting new scientific results in fields as diverse as quantum theory, climate modeling and experimental mathematics, a few of which are described in this article. Such developments suggest that in the future, the numeric <span class="hlt">precision</span> used for a scientific computation may be as important to the program design as are the algorithms and data structures.</p> <div class="credits"> <p class="dwt_author">Bailey, David H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-31</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">114</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/1651308"> <span id="translatedtitle">Importance of <span class="hlt">precise</span> <span class="hlt">positioning</span> for proton beam therapy in the base of skull and cervical spine.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Using proton beam therapy, high doses have been delivered to chordomas and chondrosarcomas of the base of skull and cervical spine. Dose inhomogeneity to the tumors has been accepted in order to maintain normal tissue tolerances, and detailed attention to patient immobilization and to <span class="hlt">precise</span> <span class="hlt">positioning</span> has minimized the margins necessary to ensure these dose constraints. This study examined the contribution of <span class="hlt">precise</span> <span class="hlt">positioning</span> to the better dose localization achieved in these treatments. Three patients whose tumors represented different anatomic geometries were studied. Treatment plans were developed which treated as much of the tumor as possible to 74 Cobalt-Gray-Equivalent (CGE) while maintaining the central brain stem and central spinal cord at less than or equal to 48 CGE, the surface of the brain stem, surface of the spinal cord, and optic structures at less than or equal to 60 CGE, and the temporal lobes at less than or equal to 5% likelihood of complication using a biophysical model of normal tissue complication probability. Two <span class="hlt">positioning</span> accuracies were assumed: 3 mm and 10 mm. Both proton beam plans and 10 MV X ray beam plans were developed with these assumptions and dose constraints. In all cases with the same <span class="hlt">positioning</span> uncertainties, the proton beam plans delivered more dose to a larger percentage of the tumor volume and the estimated tumor control probability was higher than with the X ray plans. However, without <span class="hlt">precise</span> <span class="hlt">positioning</span> both the proton plans and the X ray plans deteriorated, with a 12% to 25% decrease in estimated tumor control probability. In all but one case, the difference between protons with good <span class="hlt">positioning</span> and poor <span class="hlt">positioning</span> was greater than the difference between protons and X rays, both with good <span class="hlt">positioning</span>. Hence in treating these tumors, which are in close proximity to critical normal tissues, attention to immobilization and <span class="hlt">precise</span> <span class="hlt">positioning</span> is essential. With good <span class="hlt">positioning</span>, proton beam therapy permits higher doses to significantly more of the tumor in these sites than do X rays. PMID:1651308</p> <div class="credits"> <p class="dwt_author">Tatsuzaki, H; Urie, M M</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">115</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19760034954&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">ATS-6 - Spacecraft Attitude <span class="hlt">Precision</span> <span class="hlt">Pointing</span> and Slewing Adaptive Control Experiment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The primary objective of the Spacecraft Attitude <span class="hlt">Precision</span> <span class="hlt">Pointing</span> and Slewing Adaptive Control (SAPPSAC) experiment is to establish feasibility and evaluate capabilities of a ground-based spacecraft attitude control system, wherein RF command and telemetry links, together with a ground station on-line minicomputer, perform closed loop attitude control of the Applications Technology Satellite-6 (ATS-6). The ground processor is described, including operational characteristics and the controller software. Attitude maneuvers include <span class="hlt">precision</span> <span class="hlt">pointing</span> to fixed targets, slewing between targets, and generation of prescribed ground tracks. Test results show high performance and reliability for over 30 hours of on-line control with no serious anomalies. Attitude stabilization relative to a prescribed target has been achieved to better than 0.007 deg in pitch and roll and 0.02 deg in yaw for a period of 43 min. Ground tracks were generated which had maximum latitude/longitude deviations less than 0.15 deg from reference.</p> <div class="credits"> <p class="dwt_author">Isley, W. C.; Endres, D. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">1975-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">116</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50890504"> <span id="translatedtitle">An Operand-Optimized Asynchronous IEEE 754 Double-<span class="hlt">Precision</span> Floating-<span class="hlt">Point</span> Adder</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We present the design and implementation of an asynchronous high-performance IEEE 754 compliant double <span class="hlt">precision</span> floating-<span class="hlt">point</span> adder (FPA). We provide a detailed breakdown of the power consumption of the FPA datapath, and use it to motivate a number of different data-dependent optimizations for energy-efficiency. Our baseline asynchronous FPA has a throughput of 2.15 GHz while consuming 69.3 pJ per operation</p> <div class="credits"> <p class="dwt_author">Basit Riaz Sheikh; Rajit Manohar</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">117</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/4235245"> <span id="translatedtitle">An FPGA Implementation of a Fully Verified Double <span class="hlt">Precision</span> IEEE Floating-<span class="hlt">Point</span> Adder</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We report on the full gate-level verification and FPGA implementation of a highly optimized double <span class="hlt">precision</span> IEEE floating-<span class="hlt">point</span> adder. The proposed adder design incorporates many optimizations like a nonstandard separation into two paths, a simple rounding algorithm, unification of rounding cases for addition and subtraction, sign-magnitude computation of a difference based on one's complement subtraction, compound adders, and fast circuits</p> <div class="credits"> <p class="dwt_author">Nikhil Kikkeri; Peter-michael Seidel</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">118</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013SPIE.8580E..19J"> <span id="translatedtitle">A device to improve the SNR of the measurement of the <span class="hlt">positional</span> floating reference <span class="hlt">point</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Previous studies have preliminarily validated the floating reference method and shown that it has the potential to improve the accuracy of non-invasive blood glucose sensing by Near-Infrared Spectroscopy. In order to make this method practical, it is necessary to <span class="hlt">precisely</span> verify and measure the existence and variation features of the <span class="hlt">positional</span> floating reference <span class="hlt">point</span>. In this talk, a device which can <span class="hlt">precisely</span> verify and measure the <span class="hlt">positional</span> floating reference <span class="hlt">point</span> is built. Since the light intensity of diffuse reflectance from the tested sample is very weak, a multipath detecting fibers system was built to improve signal-to-noise ratio. In this system, the fibers encircle the light source fiber which is regarded as the reference center of detecting fibers while they are moving. In addition, the <span class="hlt">position</span> of each fiber is accurately controlled by manual translation stage to keep all detecting fibers always in the same radius around light source fiber. This ensures that received signal is coming from the same radial distance of light source. The variation of signal-to-noise ratio along with the different radial distance was investigated based on experiments. Results show that the application of this device could improve signal-to-noise ratio, and provide a new experimental method for the further study of <span class="hlt">positional</span> floating reference <span class="hlt">point</span>.</p> <div class="credits"> <p class="dwt_author">Jiang, Jingying; Rong, Xuzheng; Zhang, Hao; Xu, Kexin</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">119</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19930016923&hterms=matlab+sensor&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmatlab%2Bsensor"> <span id="translatedtitle">Applications of inertial-sensor high-inheritance instruments to DSN <span class="hlt">precision</span> antenna <span class="hlt">pointing</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Laboratory test results of the initialization and tracking performance of an existing inertial-sensor-based instrument are given. The instrument, although not primarily designed for <span class="hlt">precision</span> antenna <span class="hlt">pointing</span> applications, demonstrated an on-average 10-hour tracking error of several millidegrees. The system-level instrument performance is shown by analysis to be sensor limited. Simulated instrument improvements show a tracking error of less than 1 mdeg, which would provide acceptable performance, i.e., low <span class="hlt">pointing</span> loss, for the DSN 70-m antenna sub network, operating at Ka-band (1-cm wavelength).</p> <div class="credits"> <p class="dwt_author">Goddard, R. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">120</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19920020128&hterms=q-angle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dq-angle"> <span id="translatedtitle">Applications of inertial-sensor high-inheritance instruments to DSN <span class="hlt">precision</span> antenna <span class="hlt">pointing</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Laboratory test results of the initialization and tracking performance of an existing inertial-sensor-based instrument are given. The instrument, although not primarily designed for <span class="hlt">precision</span> antenna <span class="hlt">pointing</span> applications, demonstrated an on-average 10-hour tracking error of several millidegrees. The system-level instrument performance is shown by analysis to be sensor limited. Simulated instrument improvements show a tracking error of less than 1 mdeg, which would provide acceptable performance, i.e., low <span class="hlt">pointing</span> loss, for the Deep Space Network 70-m antenna subnetwork, operating at Ka-band (1-cm wavelength).</p> <div class="credits"> <p class="dwt_author">Goddard, R. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_5");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">121</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/25322238"> <span id="translatedtitle"><span class="hlt">Precision</span> absolute measurement and alignment of laser beam direction and <span class="hlt">position</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">For the construction of high-<span class="hlt">precision</span> optical assemblies, direction and <span class="hlt">position</span> measurement and control of the involved laser beams are essential. While optical components such as beamsplitters and mirrors can be <span class="hlt">positioned</span> and oriented accurately using coordinate measuring machines (CMMs), the <span class="hlt">position</span> and direction control of laser beams is a much more intriguing task since the beams cannot be physically contacted. We present an easy-to-implement method to both align and measure the direction and <span class="hlt">position</span> of a laser beam using a CMM in conjunction with a <span class="hlt">position</span>-sensitive quadrant photodiode. By comparing our results to calibrated angular and <span class="hlt">positional</span> measurements we can conclude that with the proposed method, a laser beam can be both measured and aligned to the desired direction and <span class="hlt">position</span> with 10 ?rad angular and 3 ?m <span class="hlt">positional</span> accuracy. PMID:25322238</p> <div class="credits"> <p class="dwt_author">Schütze, Daniel; Müller, Vitali; Heinzel, Gerhard</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">122</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3348824"> <span id="translatedtitle">Compact Integration of a GSM-19 Magnetic Sensor with High-<span class="hlt">Precision</span> <span class="hlt">Positioning</span> using VRS GNSS Technology</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Magnetic data consists of a sequence of collected <span class="hlt">points</span> with spatial coordinates and magnetic information. The spatial location of these <span class="hlt">points</span> needs to be as exact as possible in order to develop a <span class="hlt">precise</span> interpretation of magnetic anomalies. GPS is a valuable tool for accomplishing this objective, especially if the RTK approach is used. In this paper the VRS (Virtual Reference Station) technique is introduced as a new approach for real-time <span class="hlt">positioning</span> of magnetic sensors. The main advantages of the VRS approach are, firstly, that only a single GPS receiver is needed (no base station is necessary), reducing field work and equipment costs. Secondly, VRS can operate at distances separated 50–70 km from the reference stations without degrading accuracy. A compact integration of a GSM-19 magnetometer sensor with a geodetic GPS antenna is presented; this integration does not diminish the operational flexibility of the original magnetometer and can work with the VRS approach. The coupled devices were tested in marshlands around Gandia, a city located approximately 100 km South of Valencia (Spain), thought to be the site of a Roman cemetery. The results obtained show adequate geometry and high-<span class="hlt">precision</span> <span class="hlt">positioning</span> for the structures to be studied (a comparison with the original low <span class="hlt">precision</span> GPS of the magnetometer is presented). Finally, the results of the magnetic survey are of great interest for archaeological purposes. PMID:22574055</p> <div class="credits"> <p class="dwt_author">Martin, Angel; Padin, Jorge; Anquela, Ana Belen; Sanchez, Juan; Belda, Santiago</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">123</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1759002"> <span id="translatedtitle">Tobacco <span class="hlt">point</span> of sale advertising increases <span class="hlt">positive</span> brand user imagery</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Objectives: To determine the potential impact of <span class="hlt">point</span> of sale advertising on adolescents so as to inform changes to the Tobacco Control Act. Design: Participants were randomly assigned to one of two conditions. In the control condition, students were exposed to a photograph of a packet of cigarettes; in the intervention condition, students were exposed to an ad for cigarettes, typical of <span class="hlt">point</span> of sale advertising posters. All students then rated the brand user on a set of 12 bipolar adjectives. Two brands were used in the study: Benson & Hedges, and Marlboro. Subjects: One hundred year (grade) 6 and 7 students (age range 10–12 years), from four Western Australian metropolitan primary schools, participated in the study. Results: In a majority of the brand user descriptions, the cigarette advertisements increased brand user imagery in a <span class="hlt">positive</span> way, especially for Benson & Hedges. For example, participants viewing the Benson & Hedges advertisement, as distinct from those viewing the Benson & Hedges pack only, were more likely to describe the Benson & Hedges user as relaxed, interesting, cool, rich, adventurous, and classy. Relative to the Marlboro pack only, the Marlboro ad increased <span class="hlt">positive</span> perceptions of the Marlboro user on adventurous, interesting, and relaxed. Conclusions: The results presented here support restrictions being placed on advertising at <span class="hlt">point</span> of sale, since such ads have the potential to increase <span class="hlt">positive</span> brand user imagery directly in the situation where a product purchase can take place, and hence the potential to increase the likelihood of impulse purchasing. PMID:12198267</p> <div class="credits"> <p class="dwt_author">Donovan, R; Jancey, J; Jones, S</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">124</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://acl.mit.edu/papers/2002_MSEC_93.pdf"> <span id="translatedtitle">GPS Estimation Algorithms for <span class="hlt">Precise</span> Velocity, Slip and Race-track <span class="hlt">Position</span> Measurements</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">-phase differential GPS (CDGPS) for race car applications. In particular, experimental results are presented benefit for this work would be a new way to measure and present coaching information to a race car driver02MSEC-93 GPS Estimation Algorithms for <span class="hlt">Precise</span> Velocity, Slip and Race-track <span class="hlt">Position</span> Measurements</p> <div class="credits"> <p class="dwt_author">How, Jonathan P.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">125</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/53487548"> <span id="translatedtitle"><span class="hlt">Precision</span> spacecraft rendezvous using global <span class="hlt">positioning</span> system: An integrated hardware approach</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The objective of this dissertation is to develop a <span class="hlt">precision</span> rendezvous methodology for Earth orbiting spacecraft utilizing the Global <span class="hlt">Positioning</span> System (GPS). A GPS receiver is placed on each space vehicle and a communication link is used to pass GPS measurements from the target to the chaser spacecraft. The integrated navigation and guidance system resides on the chaser vehicle. The</p> <div class="credits"> <p class="dwt_author">Takuji Ebinuma</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">126</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50874567"> <span id="translatedtitle">Status and prospects of differential navigation and high <span class="hlt">precision</span> <span class="hlt">positioning</span> GNSS-technologies in Ukraine</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The results of the analysis of status and prospects of differential navigation and high <span class="hlt">precision</span> <span class="hlt">positioning</span> using GNSS and their functional augmentations in the world and in Ukraine are stated. The ways of implementation in Ukraine of up-to-date technologies and EGNOS, EUPOS systems, prospects and tasks of development of domestic satellite navigation service are analyzed.</p> <div class="credits"> <p class="dwt_author">A. Zhalilo; V. Shokalo</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">127</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/1464643"> <span id="translatedtitle"><span class="hlt">Precise</span> tracking of remote sensing satellites with the Global <span class="hlt">Positioning</span> System</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Global <span class="hlt">Positioning</span> System (GPS) can be applied in a number of ways to track remote sensing satellites at altitudes below 3000 km with accuracies of better than 10 cm. All techniques use a <span class="hlt">precise</span> global network of GPS ground receivers operating in concert with a receiver aboard the user satellite, and all estimate the user orbit, GPS orbits, and</p> <div class="credits"> <p class="dwt_author">THOMAS P. YUNCK; SIEN-CHONG WU; JIUN-TSONG WU; CATHERINE L. THORNTON</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">128</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50694987"> <span id="translatedtitle">Pulsed frequency modulation techniques for high-<span class="hlt">precision</span> ultra wideband ranging and <span class="hlt">positioning</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this paper a novel approach for a high <span class="hlt">precision</span> local <span class="hlt">positioning</span> radar using an ultra wideband technique is presented. The concept is based on the standard FMCW (frequency modulated continuous wave) radar principle combined with short pulses to fulfill the emission limits given by the official regulatory authorities. The system combines the advantages of FMCW radar systems and the</p> <div class="credits"> <p class="dwt_author">Benjamin Waldmann; Robert Weigel; Peter Gulden; Martin Vossiek</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">129</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50687883"> <span id="translatedtitle">Method for high <span class="hlt">precision</span> local <span class="hlt">positioning</span> radar using an ultra wideband technique</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this paper, a novel approach for a high <span class="hlt">precision</span> local <span class="hlt">positioning</span> radar using an ultra wideband technique is presented. The concept is based on the standard FMCW (frequency modulated continuous wave) radar principle combined with short pulses to fulfill the emission limits given by the official regulatory authorities. With this concept, a high accuracy in dense multipath indoor environments</p> <div class="credits"> <p class="dwt_author">Benjamin Waldmann; Robert Weigel; Peter Gulden</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">130</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50990044"> <span id="translatedtitle">Towards <span class="hlt">precise</span> car navigation: Detection of relative vehicle <span class="hlt">position</span> on highway for collision avoidance</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this paper, we focus on evaluating the performance of NTrip\\/RTK solutions for accurate and <span class="hlt">precise</span> car navigation (analysis of both the accuracy and availibility of RTK data using mobile communication). Our approach is to develop a functional system of determining lane <span class="hlt">positions</span> on highways. A system is based on wireless radio communication among surrounding vehicles what complement and enhance</p> <div class="credits"> <p class="dwt_author">M. Uradzinski; Jingnan Liu; Weiping Jiang</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">131</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007ArtSa..42..149F"> <span id="translatedtitle">Code Single <span class="hlt">Point</span> <span class="hlt">Positioning</span> Using Nominal GNSS Constellations (Future Perception)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Global Navigation Satellite Systems (GNSS) have an endless number of applications in industry, science, military, transportation and recreation & sports. Two systems are currently in operation, namely GPS (the USA Global <span class="hlt">Positioning</span> System) and GLONASS (the Russian GLObal NAvigation Satellite System), and a third is planned, the European satellite navigation system GALILEO. The potential performance improvements achievable through combining these systems could be significant and expectations are high. The need is inevitable to explore the future of <span class="hlt">positioning</span> from different nominal constellations. In this research paper, Bernese 5.0 software could be modified to simulate and process GNSS observations from three different constellations (GPS, GLONASS and Galileo) using different combinations. This study presents results of code single <span class="hlt">point</span> <span class="hlt">positioning</span> for five stations using the three constellations and different combinations.</p> <div class="credits"> <p class="dwt_author">Farah, A. M. A.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">132</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19910011880&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">Sliding mode control of magnetic suspensions for <span class="hlt">precision</span> <span class="hlt">pointing</span> and tracking applications</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A recently developed nonlinear control method, sliding mode control, is examined as a means of advancing the achievable performance of space-based <span class="hlt">precision</span> <span class="hlt">pointing</span> and tracking systems that use nonlinear magnetic actuators. Analytic results indicate that sliding mode control improves performance compared to linear control approaches. In order to realize these performance improvements, <span class="hlt">precise</span> knowledge of the plant is required. Additionally, the interaction of an estimating scheme and the sliding mode controller has not been fully examined in the literature. Estimation schemes were designed for use with this sliding mode controller that do not seriously degrade system performance. The authors designed and built a laboratory testbed to determine the feasibility of utilizing sliding mode control in these types of applications. Using this testbed, experimental verification of the authors' analyses is ongoing.</p> <div class="credits"> <p class="dwt_author">Misovec, Kathleen M.; Flynn, Frederick J.; Johnson, Bruce G.; Hedrick, J. Karl</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">133</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21436149"> <span id="translatedtitle">Preliminary Results on Setup <span class="hlt">Precision</span> of Prone-Lateral Patient <span class="hlt">Positioning</span> for Whole Breast Irradiation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Purpose: The aim of this study was to develop a rapid and reproducible technique for prone <span class="hlt">positioning</span> and to compare dose-volume indices in prone and supine <span class="hlt">positions</span>. Methods and Materials: Eighteen patients underwent computed tomography imaging for radiotherapy planning in prone and supine <span class="hlt">position</span>. Experience was gained in the first eight patients, which lead to modifications of the Horizon prone breast board (Civco Medical Solutions, Orange City, Iowa, USA) and the patient setup technique. A unilateral breast holder (U-BH) was developed (Van de Velde, Schellebelle, Belgium) to retract the contralateral breast away from the treated breast. The technique was then applied to an additional 10 patients. The setup <span class="hlt">precision</span> was evaluated using daily cone-beam CT. Results: Modifications to the breast board were made to secure a prone-lateral rather then a pure prone <span class="hlt">position</span>. We evolved from a classical setup using laser marks on the patients' body to a direct breast setup using marks on the breast only. The setup <span class="hlt">precision</span> of the direct <span class="hlt">positioning</span> procedure with the modified breast board and the U-BH is comparable to supine setup data in the literature. Dose-volume indices for heart and lung show significantly better results for prone than for supine <span class="hlt">position</span>, and dose homogeneity within the treated breast did not differ according to the treatment <span class="hlt">position</span>. Conclusions: The setup <span class="hlt">precision</span> of our prone-lateral <span class="hlt">positioning</span> technique is comparable to supine data in literature. Our data show the advantage of prone radiotherapy to spare the lung and heart. Further research is necessary to reduce the duration of prone setup.</p> <div class="credits"> <p class="dwt_author">Veldeman, Liv, E-mail: Liv.Veldeman@uzgent.b [Department of Radiotherapy, Ghent University Hospital, Ghent (Belgium); Speleers, Bruno; Bakker, Marlies; Jacobs, Filip; Coghe, Marc; De Gersem, Werner; Impens, Aline; Nechelput, Sarah; De Wagter, Carlos [Department of Radiotherapy, Ghent University Hospital, Ghent (Belgium)</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">134</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004AGUFM.G21A0141K"> <span id="translatedtitle">A Synthetic Test of <span class="hlt">Precision</span> in GPS/Acoustic Measurements of Seafloor <span class="hlt">Positioning</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this decade, much efforts have been made in detecting seafloor movement using GPS/Acoustic ranging method. GPS/Acoustic measurement consists of two parts, one is the <span class="hlt">positioning</span> of a transducer at sea surface using K-GPS and the other is measuring travel-time or slant-range between the transducer and transponders put on ocean bottom using acoustic ranging. Currently <span class="hlt">precision</span> of the seafloor <span class="hlt">positioning</span> reaches less than 10cm. Several possible factors arise, which still decrease the <span class="hlt">precision</span>, such as GPS <span class="hlt">positioning</span> itself in 1 Hz, interpolating of exact <span class="hlt">position</span> of the transducer at an arbitrary timing of acoustic measurement, uncertainty of the sound velocity variation both in time and space as well as depth variation due mainly to ocean tide. A linear or spline interpolation can be applied to undulation of the transducer <span class="hlt">position</span> when GPS antennas and the transducer are equipped on a ship. On the contrary when using a buoy system, one need additional physical sensors to detect flutter of the buoy in higher frequency. For the sound velocity, one can estimate it based on CTD or XCTD/XBT data. However, such data cannot cover entire period and space of observation. In general, sound velocity thought to varies smaller in lateral than in time. Accounting for this nature, Scripps group developed a strategy that set transponders like triangle and make acoustic measurement with the transducer kept laterally equidistant to the transponders. In this method most of laterally stratified component of sound velocity variation in time will be cancelled to determine the center of the triangle. Prior to this measurement, <span class="hlt">position</span> of individual transponder must be estimated. Error in this estimation will biases the ``absolute'' final <span class="hlt">position</span> of the center, which is not important to detect the crustal ``relative'' movement, as long as one take the same estimations in the next survey. However this error increase the misfit of travel-time, which results in the final <span class="hlt">position</span> to be sensitive to other possible error source. Therefore <span class="hlt">position</span> of the individual transponder should be solved simultaneously with the center <span class="hlt">position</span>. In addition, we have to account for the randomness of the error to consider the ``mean distribution'' of the center <span class="hlt">position</span> as the <span class="hlt">precision</span> of survey. We will present theoretical estimate of the <span class="hlt">precision</span> with an application to actual data set.</p> <div class="credits"> <p class="dwt_author">Kido, M.; Sweeney, A. D.; Osada, Y.; Fujimoto, H.; Miura, S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">135</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10136166"> <span id="translatedtitle">Input shaping for three-dimensional slew maneuvers of a <span class="hlt">precision</span> <span class="hlt">pointing</span> flexible spacecraft</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A method is presented for input torque shaping for three-dimensional slew maneuvers of a <span class="hlt">precision</span> <span class="hlt">pointing</span> flexible spacecraft. The method determines the torque profiles for fixed-time, rest-to-rest maneuvers which minimizes a specified performance index. Spacecraft dynamics are formulated in such a manner that the rigid body and flexible motions are decoupled. Furthermore, assembly by making use of finite element analysis results. Input torque profiles are determined by solving an associated optimization problem using dynamic programming. Three example problems are provided to demonstrate the application of the method.</p> <div class="credits"> <p class="dwt_author">Dohrmann, C.R.; Robinett, R.D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">136</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004IJTIA.124..607I"> <span id="translatedtitle">GA-Based Autonomous Design of Robust Fast and <span class="hlt">Precise</span> <span class="hlt">Positioning</span> Considering Machine Stand Vibration Suppression</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This paper presents a novel Genetic Algorithm (GA)-based autonomous compensator design and <span class="hlt">position</span> command shaping considering the stand vibration suppression for the fast-response and high-<span class="hlt">precision</span> <span class="hlt">positioning</span> of mechatronic systems. The <span class="hlt">positioning</span> system is mainly composed of a robust 2-degrees-of-freedom (2DOF) controller based on the coprime factorization description. The feedback compensator based on H? design framework in the 2DOF controller ensures the robustness against the variations of resonant vibration mode. The feedforward compensator and <span class="hlt">position</span> command, on the other hand, can be autonomously designed by the optimization capability of GA, in order to achieve the desired <span class="hlt">positioning</span> performance and to suppress the machine stand vibration. The effectiveness of the proposed optimal design has been verified by experiments using a table drive system with ball screw.</p> <div class="credits"> <p class="dwt_author">Ito, Kazuaki; Nagata, Ryo; Iwasaki, Makoto; Matsui, Nobuyuki</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">137</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3386681"> <span id="translatedtitle">A High <span class="hlt">Precision</span> <span class="hlt">Position</span> Sensor Design and Its Signal Processing Algorithm for a Maglev Train</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">High <span class="hlt">precision</span> <span class="hlt">positioning</span> technology for a kind of high speed maglev train with an electromagnetic suspension (EMS) system is studied. At first, the basic structure and functions of the <span class="hlt">position</span> sensor are introduced and some key techniques to enhance the <span class="hlt">positioning</span> <span class="hlt">precision</span> are designed. Then, in order to further improve the <span class="hlt">positioning</span> signal quality and the fault-tolerant ability of the sensor, a new kind of discrete-time tracking differentiator (TD) is proposed based on nonlinear optimal control theory. This new TD has good filtering and differentiating performances and a small calculation load. It is suitable for real-time signal processing. The stability, convergence property and frequency characteristics of the TD are studied and analyzed thoroughly. The delay constant of the TD is figured out and an effective time delay compensation algorithm is proposed. Based on the TD technology, a filtering process is introduced in to improve the <span class="hlt">positioning</span> signal waveform when the sensor is under bad working conditions, and a two-sensor switching algorithm is designed to eliminate the <span class="hlt">positioning</span> errors caused by the joint gaps of the long stator. The effectiveness and stability of the sensor and its signal processing algorithms are proved by the experiments on a test train during a long-term test run. PMID:22778582</p> <div class="credits"> <p class="dwt_author">Xue, Song; Long, Zhiqiang; He, Ning; Chang, Wensen</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">138</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22778582"> <span id="translatedtitle">A high <span class="hlt">precision</span> <span class="hlt">position</span> sensor design and its signal processing algorithm for a maglev train.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">High <span class="hlt">precision</span> <span class="hlt">positioning</span> technology for a kind of high speed maglev train with an electromagnetic suspension (EMS) system is studied. At first, the basic structure and functions of the <span class="hlt">position</span> sensor are introduced and some key techniques to enhance the <span class="hlt">positioning</span> <span class="hlt">precision</span> are designed. Then, in order to further improve the <span class="hlt">positioning</span> signal quality and the fault-tolerant ability of the sensor, a new kind of discrete-time tracking differentiator (TD) is proposed based on nonlinear optimal control theory. This new TD has good filtering and differentiating performances and a small calculation load. It is suitable for real-time signal processing. The stability, convergence property and frequency characteristics of the TD are studied and analyzed thoroughly. The delay constant of the TD is figured out and an effective time delay compensation algorithm is proposed. Based on the TD technology, a filtering process is introduced in to improve the <span class="hlt">positioning</span> signal waveform when the sensor is under bad working conditions, and a two-sensor switching algorithm is designed to eliminate the <span class="hlt">positioning</span> errors caused by the joint gaps of the long stator. The effectiveness and stability of the sensor and its signal processing algorithms are proved by the experiments on a test train during a long-term test run. PMID:22778582</p> <div class="credits"> <p class="dwt_author">Xue, Song; Long, Zhiqiang; He, Ning; Chang, Wensen</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">139</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/x02422781512j5p1.pdf"> <span id="translatedtitle">Airborne vector gravimetry using <span class="hlt">precise</span>, <span class="hlt">position</span>-aided inertial measurement units</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Vector gravimetry using a <span class="hlt">precise</span> inertial navigation system continually updated with external <span class="hlt">position</span> data, for example\\u000a using GPS, is studied with respect to two problems. The first concerns the attitude accuracy requirement for horizontal gravity\\u000a component estimation. With covariance analyses in the space and frequency domains it is argued that with relatively stable\\u000a uncompensated gyro drift, the short-wavelength gravity vector</p> <div class="credits"> <p class="dwt_author">Christopher Jekeli</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">140</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/51177663"> <span id="translatedtitle">System Identification and Contour Tracking of a Plane-Type 3DOF <span class="hlt">Precision</span> <span class="hlt">Positioning</span> Table</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this paper, an adaptive backstepping control (ABC) method for a plane-type 3-DOF (X,Y,?z) <span class="hlt">precision</span> <span class="hlt">positioning</span> table is proposed. First, according to the dynamics of a mechanical mass-spring system, we establish mathematical equations that contain linear viscous frictions and varied elasticities with cross-coupling effects due to mechanical bending. In system identification, the real-coded genetic algorithm (RGA) method is employed to</p> <div class="credits"> <p class="dwt_author">Rong-Fong Fung; Wang-Chi Lin</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_6");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' 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showDiv("page_9");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">141</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011IJTIA.131..932M"> <span id="translatedtitle">Fast and <span class="hlt">Precise</span> <span class="hlt">Positioning</span> Using Sequential Adaptive Feedfoward Compensation for Disturbance</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This paper presents a performance improvement of trajectory tracking for the fast-response and high-<span class="hlt">precision</span> <span class="hlt">positioning</span> by a sequential adaptive compensation for disturbance. A mathematical disturbance model formulated and parameterized by an iterative learning process can estimate the actual disturbance, and the model can be sequentially adapted by a recursive least-squares method so that it shows the adaptive property against disturbance variations. The proposed <span class="hlt">positioning</span> control approach involving disturbance modeling and compensation has been verified by experiments using a linear motor-driven table system.</p> <div class="credits"> <p class="dwt_author">Maebashi, Wataru; Ito, Kazuaki; Iwasaki, Makoto</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">142</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014E%26ES...18a2035I"> <span id="translatedtitle">Effect of Radio Frequency Interference (RFI) on the <span class="hlt">Precision</span> of GPS Relative <span class="hlt">Positioning</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The successful of GPS observations are dependent on several factors between satellite vehicles and GPS receivers, where low GPS power levels have led to the threat of radio frequency interference (RFI) on the GPS signals. This study was conducted to evaluate the effect of RFI on the <span class="hlt">precision</span> of <span class="hlt">positions</span> of single and dual frequency receivers through relative <span class="hlt">positioning</span> technique by taking into consideration the radius of GPS receiver from interference source, length of baseline and response of rejection. Several tests were conducted in real environment by simulating the interference signal towards GPS receivers in the nominated GPS L1 and L2 bands. Calculations were made to indentify the distance and interference signal power between interference source and GPS receiver in order to investigate the level of effect. To be able to study this effect on the <span class="hlt">precision</span> of GPS <span class="hlt">positions</span>, the 3D residual <span class="hlt">positions</span> and geometric dilution of <span class="hlt">precision</span> (GDOP) have been used. The findings of this study have demonstrated that a sufficient time for the GPS receiver to respond in particular interference signal power level and the radius from the interference source were made as compared to previous work. It was also indicated that the residual <span class="hlt">positions</span> and GDOPs were affected proportionally when nearly to interference source but not similar for both days due to GPS coverage and other probable errors. Therefore, a good investigation on RFI towards GPS signals should be conducted in secured environment which can control the various GPS error parameters in order to obtain a reliable result on this effect.</p> <div class="credits"> <p class="dwt_author">Idris, A. N.; Sathyamoorthy, D.; Suldi, A. M.; Hamid, J. R. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">143</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20090019029&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">Track Level Compensation Look-up Table Improves Antenna <span class="hlt">Pointing</span> <span class="hlt">Precision</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The <span class="hlt">pointing</span> accuracy of the NASA Deep Space Network antennas is significantly impacted by the unevenness of the antenna azimuth track. The track unevenness causes repeatable antenna rotations, and repeatable <span class="hlt">pointing</span> errors. The paper presents the improvement of the <span class="hlt">pointing</span> accuracy of the antennas by implementing the track-level-compensation look-up table. The table consists of three axis rotations of the alidade as a function of the azimuth <span class="hlt">position</span>. The paper presents the development of the table, based on the measurements of the inclinometer tilts, processing the measurement data, and determination of the three-axis alidade rotations from the tilt data. It also presents the determination of the elevation and cross-elevation errors of the antenna as a function of the alidade rotations. The <span class="hlt">pointing</span> accuracy of the antenna with and without a table was measured using various radio beam <span class="hlt">pointing</span> techniques. The <span class="hlt">pointing</span> error decreased when the table was used, from 1.5 mdeg to 1.2 mdeg in elevation, and from 20.4 mdeg to 2.2 mdeg in cross-elevation.</p> <div class="credits"> <p class="dwt_author">Gawronski, Wodek; Baher, Farrokh; Gama, Eric</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">144</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AdSpR..52..466C"> <span id="translatedtitle">DORIS-based <span class="hlt">point</span> mascons for the long term stability of <span class="hlt">precise</span> orbit solutions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In recent years non-tidal Time Varying Gravity (TVG) has emerged as the most important contributor in the error budget of <span class="hlt">Precision</span> Orbit Determination (POD) solutions for altimeter satellites' orbits. The Gravity Recovery And Climate Experiment (GRACE) mission has provided POD analysts with static and time-varying gravity models that are very accurate over the 2002-2012 time interval, but whose linear rates cannot be safely extrapolated before and after the GRACE lifespan. One such model based on a combination of data from GRACE and Lageos from 2002-2010, is used in the dynamic POD solutions developed for the Geophysical Data Records (GDRs) of the Jason series of altimeter missions and the equivalent products from lower altitude missions such as Envisat, Cryosat-2, and HY-2A. In order to accommodate long-term time-variable gravity variations not included in the background geopotential model, we assess the feasibility of using DORIS data to observe local mass variations using <span class="hlt">point</span> mascons. In particular, we show that the <span class="hlt">point</span>-mascon approach can stabilize the geographically correlated orbit errors which are of fundamental interest for the analysis of regional Mean Sea Level trends based on altimeter data, and can therefore provide an interim solution in the event of GRACE data loss. The time series of <span class="hlt">point</span>-mass solutions for Greenland and Antarctica show good agreement with independent series derived from GRACE data, indicating a mass loss at rate of 210 Gt/year and 110 Gt/year respectively.</p> <div class="credits"> <p class="dwt_author">Cerri, L.; Lemoine, J. M.; Mercier, F.; Zelensky, N. P.; Lemoine, F. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">145</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012EGUGA..1412957K"> <span id="translatedtitle">The significance of GPS/leveling <span class="hlt">points</span> for the high <span class="hlt">precision</span> geoid computation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The computation of a local geoid can be done by several methods. Collocation as one of the possible tools has the big advantage that observations representing different functionals of the disturbing potential can be combined. Therefore also GPS/leveling <span class="hlt">points</span> can be used as observation values. The present work discusses the significance of GPS/leveling data in the collocation process as well as the overall importance of this kind of data in the field of the high <span class="hlt">precision</span> geoid computation. Several basic principles are discussed. Is the combination of GPS/leveling data with the other gravity field observations in one step better than performing the widely used two step procedure? The two step procedure means combining gravity anomalies and deflections of the vertical in a first step, followed by the fitting of the geoidal surface to the GPS/leveling benchmarks by a transformation surface. The present work also focuses on the modeling of the transformation surface by radial base functions. An adapted version of the Greedy algorithm is used to find the minimum number of GPS/leveling <span class="hlt">points</span> that are necessary to fix the transformation surface with a given accuracy. Finally the principle of a possible validation of the GPS/leveling <span class="hlt">points</span> by a combined leave one out cross validation is discussed.</p> <div class="credits"> <p class="dwt_author">Kühtreiber, N.; Pock, C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">146</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19910008996&hterms=global+positioning+system&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2522global%2Bpositioning%2Bsystem%2522"> <span id="translatedtitle">Demonstration of <span class="hlt">precise</span> estimation of polar motion parameters with the global <span class="hlt">positioning</span> system: Initial results</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Data from the Global <span class="hlt">Positioning</span> System (GPS) were used to determine <span class="hlt">precise</span> polar motion estimates. Conservatively calculated formal errors of the GPS least squares solution are approx. 10 cm. The GPS estimates agree with independently determined polar motion values from very long baseline interferometry (VLBI) at the 5 cm level. The data were obtained from a partial constellation of GPS satellites and from a sparse worldwide distribution of ground stations. The accuracy of the GPS estimates should continue to improve as more satellites and ground receivers become operational, and eventually a near real time GPS capability should be available. Because the GPS data are obtained and processed independently from the large radio antennas at the Deep Space Network (DSN), GPS estimation could provide very <span class="hlt">precise</span> measurements of Earth orientation for calibration of deep space tracking data and could significantly relieve the ever growing burden on the DSN radio telescopes to provide Earth platform calibrations.</p> <div class="credits"> <p class="dwt_author">Lichten, S. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">147</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21060522"> <span id="translatedtitle">High-<span class="hlt">precision</span> measurement of pixel <span class="hlt">positions</span> in a charge-coupled device.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The high level of spatial uniformity in modern CCD's makes them excellent devices for astrometric instruments. However, at the level of accuracy envisioned by the more ambitious projects such as the Astrometric Imaging Telescope, current technology produces CCD's with significant pixel registration errors. We describe a technique for making high-<span class="hlt">precision</span> measurements of relative pixel <span class="hlt">positions</span>. We measured CCD's manufactured for the Wide Field Planetary Camera II installed in the Hubble Space Telescope. These CCD's are shown to have significant step-and-repeat errors of 0.033 pixel along every 34th row, as well as a 0.003-pixel curvature along 34-pixel stripes. The source of these errors is described. Our experiments achieved a per-pixel accuracy of 0.011 pixel. The ultimate shot-noise limited <span class="hlt">precision</span> of the method is less than 0.001 pixel. PMID:21060522</p> <div class="credits"> <p class="dwt_author">Shaklan, S; Sharman, M C; Pravdo, S H</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-10-10</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">148</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/25085189"> <span id="translatedtitle">Note: Three-dimensional linearization of optical trap <span class="hlt">position</span> detection for <span class="hlt">precise</span> high speed diffusion measurements.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Studies of the details of Brownian motion, hydrodynamic of colloids, or protein diffusion measurements all require high temporal and spatial resolution of the <span class="hlt">position</span> detector and a means to trap the colloid. Optical trap based thermal noise imaging employing a quadrant photodiode as detector provides such a method. However, optical trapping requires an objective with high numerical aperture resulting in highly nonlinear <span class="hlt">position</span> signal and significant cross-dependence of the three spatial directions. Local diffusion measurements are especially susceptible to distance errors. Here, we present a <span class="hlt">position</span> calibration method, which corrects nonlinearities sufficiently to allow <span class="hlt">precise</span> local diffusion measurement throughout the entire trapping volume. This correction permits us to obtain high-resolution two- and three-dimensional diffusion maps. PMID:25085189</p> <div class="credits"> <p class="dwt_author">Hsu, Y-H; Pralle, A</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">149</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20060008640&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">Track-Level-Compensation Look-Up Table Improves Antenna <span class="hlt">Pointing</span> <span class="hlt">Precision</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">This article presents the improvement of the beam-waveguide antenna <span class="hlt">pointing</span> accuracy due to the implementation of the track-level-compensation look-up table. It presents the development of the table, from the measurements of the inclinometer tilts to the processing of the measurement data and the determination of the threeaxis alidade rotations. The table consists of three axis rotations of the alidade as a function of the azimuth <span class="hlt">position</span>. The article also presents the equations to determine the elevation and cross-elevation errors of the antenna as a function of the alidade rotations and the antenna azimuth and elevation <span class="hlt">positions</span>. The table performance was verified using radio beam <span class="hlt">pointing</span> data. The <span class="hlt">pointing</span> error decreased from 4.5 mdeg to 1.4 mdeg in elevation and from 14.5 mdeg to 3.1 mdeg in cross-elevation. I. Introduction The Deep Space Station 25 (DSS 25) antenna shown in Fig. 1 is one of NASA s Deep Space Network beam-waveguide (BWG) antennas. At 34 GHz (Ka-band) operation, it is necessary to be able to track with a <span class="hlt">pointing</span> accuracy of 2-mdeg root-mean-square (rms). Repeatable <span class="hlt">pointing</span> errors of several millidegrees of magnitude have been observed during the BWG antenna calibration measurements. The systematic errors of order 4 and lower are eliminated using the antenna <span class="hlt">pointing</span> model. However, repeatable <span class="hlt">pointing</span> errors of higher order are out of reach of the model. The most prominent high-order systematic errors are the ones caused by the uneven azimuth track. The track is shown in Fig. 2. Manufacturing and installation tolerances, as well as gaps between the segments of the track, are the sources of the <span class="hlt">pointing</span> errors that reach over 14-mdeg peak-to-peak magnitude, as reported in [1,2]. This article presents a continuation of the investigations and measurements of the <span class="hlt">pointing</span> errors caused by the azimuth-track-level unevenness that were presented in [1] and [2], and it presents the implementation results. Track-level-compensation (TLC) look-up tables were created for the DSS 25, DSS 26, DSS 34, and DSS 55 antennas. To date, the most complete and detailed results were obtained for the DSS 25 and DSS 55 antennas. In this article, for brevity of presentation, we present the DSS 25 antenna results only. 1 Communications Ground Systems Section. The research described in this publication was carried out by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.</p> <div class="credits"> <p class="dwt_author">Gawronski, W.; Baher, F.; Gama, E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">150</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013ISPAr.XL1b.113E"> <span id="translatedtitle">A <span class="hlt">Precise</span> <span class="hlt">Position</span> and Attitude Determination System for Lightweight Unmanned Aerial Vehicles</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In many unmanned aerial vehicle (UAV) applications a direct georeferencing is required. The reason can be that the UAV flies autonomous and must be navigated <span class="hlt">precisely</span>, or that the UAV performs a remote sensing operation, where the <span class="hlt">position</span> of the camera has to be known at the moment of the recording. In our application, a project called Mapping on Demand, we are motivated by both of these reasons. The goal of this project is to develop a lightweight autonomously flying UAV that is able to identify and measure inaccessible three-dimensional objects by use of visual information. Due to payload and space limitations, <span class="hlt">precise</span> <span class="hlt">position</span> and attitude determination of micro- and mini-sized UAVs is very challenging. The limitations do not only affect the onboard computing capacity, but they are also noticeable when choosing the georeferencing sensors. In this article, we will present a new developed onboard direct georeferencing system which is real-time capable, applicable for lightweight UAVs and provides very <span class="hlt">precise</span> results (<span class="hlt">position</span> accuracy ? < 5 cm and attitude accuracy ? < 0.5 deg). In this system GPS, inertial sensors, magnetic field sensors, a barometer as well as stereo video cameras are used as georeferencing sensors. We will describe the hardware development and will go into details of the implemented software. In this context especially the RTK-GPS software and the concept of the attitude determination by use of inertial sensors, magnetic field sensors as well as an onboard GPS baseline will be highlighted. Finally, results of first field tests as well as an outlook on further developments will conclude this contribution.</p> <div class="credits"> <p class="dwt_author">Eling, C.; Klingbeil, L.; Wieland, M.; Kuhlmann, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">151</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014JARS....8.3588W"> <span id="translatedtitle">Automatic registration of laser <span class="hlt">point</span> cloud using <span class="hlt">precisely</span> located sphere targets</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Sphere targets are used extensively in terrestrial laser scanning registration; however, in practice, it is still a time-consuming and labor-intensive task. This paper proposes an automatic registration method for laser <span class="hlt">point</span> clouds based on sphere targets' detection. First, a modified eight-neighbors check method is applied to mark occluding edge <span class="hlt">points</span>. Then, for the sphere targets in the raster structure, occluding edge <span class="hlt">points</span> are clustered, and circle and sphere detections are sequentially implemented in the cluster node and circular area, respectively. The sphere models that pass through multilevel constraints are considered the final results. Next, triangles constructed using three arbitrary noncollinear sphere centers in each scan station are selected as registration primitives and the area and interior angles of each are selected as similarity measures. Finally, the congruent sphere centers between two scan stations are matched in an iterative manner and used to calculate the transformation matrix. The results of experiments in which a lab was scanned from two locations indicate that our method can effectively detect four sphere targets in more than 10 million <span class="hlt">point</span> clouds within ˜1.5 min, with the largest <span class="hlt">position</span> error between congruent <span class="hlt">points</span> <2 mm.</p> <div class="credits"> <p class="dwt_author">Wang, Yanmin; Shi, Hongbin; Zhang, Yanyan; Zhang, Dongmei</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">152</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19940009898&hterms=global+positioning+system&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2522global%2Bpositioning%2Bsystem%2522"> <span id="translatedtitle">Improved treatment of global <span class="hlt">positioning</span> system force parameters in <span class="hlt">precise</span> orbit determination applications</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Data collected from a worldwide 1992 experiment were processed at JPL to determine <span class="hlt">precise</span> orbits for the satellites of the Global <span class="hlt">Positioning</span> System (GPS). A filtering technique was tested to improve modeling of solar-radiation pressure force parameters for GPS satellites. The new approach improves orbit quality for eclipsing satellites by a factor of two, with typical results in the 25- to 50-cm range. The resultant GPS-based estimates for geocentric coordinates of the tracking sites, which include the three DSN sites, are accurate to 2 to 8 cm, roughly equivalent to 3 to 10 nrad of angular measure.</p> <div class="credits"> <p class="dwt_author">Vigue, Y.; Lichten, S. M.; Muellerschoen, R. J.; Blewitt, G.; Heflin, M. B.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">153</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19790026723&hterms=Schwarz&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DSchwarz"> <span id="translatedtitle">LMC X-1, X-2, and X-3 - <span class="hlt">Precise</span> <span class="hlt">positions</span> from the HEAO 1 modulation collimator</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><span class="hlt">Precise</span> (to about 20 arcsec) <span class="hlt">positions</span> are reported for the Large Magellanic Cloud X-ray sources LMC X-1, X-2, and X-3, determined with the HEAO 1 scanning modulation collimator. The error regions for LMC X-1 and X-3 contain, respectively, the B5 supergiant R148 and a possibly variable B III-IV star. Spectra taken of the latter confirm the spectral type and show that it is a member of the LMC. A search for a previously reported extended component of LMC X-1 yields upper limits which exclude it.</p> <div class="credits"> <p class="dwt_author">Johnston, M. D.; Bradt, H. V.; Doxsey, R. E.; Gursky, H.; Schwartz, D. A.; Schwarz, J.; Van Paradijs, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1978-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">154</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005JNav...58..257Q"> <span id="translatedtitle">Validation of Map Matching Algorithms using High <span class="hlt">Precision</span> <span class="hlt">Positioning</span> with GPS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Map Matching (MM) algorithms are usually employed for a range of transport telematics applications to correctly identify the physical location of a vehicle travelling on a road network. Two essential components for MM algorithms are (1) navigation sensors such as the Global <span class="hlt">Positioning</span> System (GPS) and dead reckoning (DR), among others, to estimate the <span class="hlt">position</span> of the vehicle, and (2) a digital base map for spatial referencing of the vehicle location. Previous research by the authors (Quddus et al., 2003; Ochieng et al., 2003) has developed improved MM algorithms that take account of the vehicle speed and the error sources associated with the navigation sensors and the digital map data previously ignored in conventional MM approaches. However, no validation study assessing the performance of MM algorithms has been presented in the literature. This paper describes a generic validation strategy and results for the MM algorithm previously developed in Ochieng et al. (2003). The validation technique is based on a higher accuracy reference (truth) of the vehicle trajectory as determined by high <span class="hlt">precision</span> <span class="hlt">positioning</span> achieved by the carrier-phase observable from GPS. The results show that the vehicle <span class="hlt">positions</span> determined from the MM results are within 6 m of the true <span class="hlt">positions</span>. The results also demonstrate the importance of the quality of the digital map data to the map matching process.</p> <div class="credits"> <p class="dwt_author">Quddus, Mohammed A.; Noland, Robert B.; Ochieng, Washington Y.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">155</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22163417"> <span id="translatedtitle">An integration of GPS with INS sensors for <span class="hlt">precise</span> long-baseline kinematic <span class="hlt">positioning</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Integrating the <span class="hlt">precise</span> GPS carrier phases and INS sensor technologies is a methodology that has been applied indispensably in those application fields requiring accurate and reliable <span class="hlt">position</span>, velocity, and attitude information. However, conventional integration approaches with a single GPS reference station may not fulfil the demanding performance requirements, especially in the <span class="hlt">position</span> component, when the baseline length between the reference station and mobile user's GPS receiver is greater than a few tens of kilometres. This is because their <span class="hlt">positioning</span> performance is primarily dependent on the common mode of errors of GPS measurements. To address this constraint, a novel GPS/INS integration scheme using multiple GPS reference stations is proposed here that can improve its <span class="hlt">positioning</span> accuracy by modelling the baseline-dependent errors. In this paper, the technical issues concerned with implementing the proposed scheme are described, including the GPS network correction modelling and integrated GPS/INS filtering. In addition, the results from the processing of the simulated measurements are presented to characterise the system performance. As a result, it has been established that the integration of GPS/INS with multiple reference stations would make it possible to ensure centimetre-level <span class="hlt">positioning</span> accuracy, even if the baseline length reaches about 100 km. PMID:22163417</p> <div class="credits"> <p class="dwt_author">Lee, Hungkyu</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">156</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/12425"> <span id="translatedtitle">Vibratory response modeling and verification of a high <span class="hlt">precision</span> optical <span class="hlt">positioning</span> system.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A generic vibratory-response modeling program has been developed as a tool for designing high-<span class="hlt">precision</span> optical <span class="hlt">positioning</span> systems. Based on multibody dynamics theory, the system is modeled as rigid-body structures connected by linear elastic elements, such as complex actuators and bearings. The full dynamic properties of each element are determined experimentally or theoretically, then integrated into the program as inertial and stiffness matrices. Utilizing this program, the theoretical and experimental verification of the vibratory behavior of a double-multilayer monochromator support and <span class="hlt">positioning</span> system is presented. Results of parametric design studies that investigate the influence of support floor dynamics and highlight important design issues are also presented. Overall, good matches between theory and experiment demonstrate the effectiveness of the program as a dynamic modeling tool.</p> <div class="credits"> <p class="dwt_author">Barraza, J.; Kuzay, T.; Royston, T. J.; Shu, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-06-18</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">157</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2000PhDT.......195G"> <span id="translatedtitle">Real-time, autonomous <span class="hlt">precise</span> satellite orbit determination using the global <span class="hlt">positioning</span> system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The desire for autonomously generated, rapidly available, and highly accurate satellite ephemeris is growing with the proliferation of constellations of satellites and the cost and overhead of ground tracking resources. Autonomous Orbit Determination (OD) may be done on the ground in a post-processing mode or in real-time on board a satellite and may be accomplished days, hours or immediately after observations are processed. The Global <span class="hlt">Positioning</span> System (GPS) is now widely used as an alternative to ground tracking resources to supply observation data for satellite <span class="hlt">positioning</span> and navigation. GPS is accurate, inexpensive, provides continuous coverage, and is an excellent choice for autonomous systems. In an effort to estimate <span class="hlt">precise</span> satellite ephemeris in real-time on board a satellite, the Goddard Space Flight Center (GSFC) created the GPS Enhanced OD Experiment (GEODE) flight navigation software. This dissertation offers alternative methods and improvements to GEODE to increase on board autonomy and real-time total <span class="hlt">position</span> accuracy and <span class="hlt">precision</span> without increasing computational burden. First, GEODE is modified to include a Gravity Acceleration Approximation Function (GAAF) to replace the traditional spherical harmonic representation of the gravity field. Next, an ionospheric correction method called Differenced Range Versus Integrated Doppler (DRVID) is applied to correct for ionospheric errors in the GPS measurements used in GEODE. Then, Dynamic Model Compensation (DMC) is added to estimate unmodeled and/or mismodeled forces in the dynamic model and to provide an alternative process noise variance-covariance formulation. Finally, a Genetic Algorithm (GA) is implemented in the form of Genetic Model Compensation (GMC) to optimize DMC forcing noise parameters. Application of GAAF, DRVID and DMC improved GEODE's <span class="hlt">position</span> estimates by 28.3% when applied to GPS/MET data collected in the presence of Selective Availability (SA), 17.5% when SA is removed from the GPS/MET data and 10.8% on SA free TOPEX data. <span class="hlt">Position</span> estimates with RSS errors below I meter are now achieved using SA free TOPEX data. DRVID causes an increase in computational burden while GAAF and DMC reduce computational burden. The net effect of applying GAAF, DRVID and DMC is an improvement in GEODE's accuracy/<span class="hlt">precision</span> without an increase in computational burden.</p> <div class="credits"> <p class="dwt_author">Goldstein, David Ben</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">158</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013RScI...84i3303E"> <span id="translatedtitle">A free jet (supersonic), molecular beam source with automatized, 50 nm <span class="hlt">precision</span> nozzle-skimmer <span class="hlt">positioning</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Low energy (thermal) free jet (supersonic) molecular beams are used in a range of applications from surface science and surface deposition to quantum coherence and gas kinetics experiments. A free jet molecular beam is created by a gas expansion from a high pressure reservoir through a small aperture (nozzle). The nozzle typically has a diameter of 2-20 ?m. The central part of the beam is selected using a skimmer, typically up to 500 ?m in diameter. Recent years have seen the introduction of highly spatially confined beam sources based on micrometer skimmers and micrometer or even sub-micrometer nozzles. Such sources have been applied, for example, in the investigation of superfluidity and in neutral helium microscopy. However, up till now no source design allowing the <span class="hlt">precise</span> <span class="hlt">positioning</span> of the micro-skimmer relative to the nozzle has been available. This is an important issue because the relative <span class="hlt">position</span> of skimmer and nozzle can influence the beam properties considerably. Here we present the design and implementation of a new molecular beam source, which allows an automatized, 50 nm <span class="hlt">precision</span> <span class="hlt">positioning</span> of the skimmer relative to the nozzle. The source is liquid nitrogen cooled and the temperature can be controlled between 110 K and 350 K with a temperature fluctuation of less than ±0.1 K over several hours. Beam intensity measurements using a 5 ?m nozzle and a skimmer 5 ?m in diameter are presented for stagnation pressures po in the range 3-180 bars. A 2D beam profile scan, using a 9.5 ?m skimmer and a 5 ?m nozzle is presented as a further documentation of the versatility of the new design and as an illustration of the influence of the relative skimmer-nozzle <span class="hlt">position</span> on the beam properties.</p> <div class="credits"> <p class="dwt_author">Eder, S. D.; Samelin, B.; Bracco, G.; Ansperger, K.; Holst, B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">159</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24089819"> <span id="translatedtitle">A free jet (supersonic), molecular beam source with automatized, 50 nm <span class="hlt">precision</span> nozzle-skimmer <span class="hlt">positioning</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Low energy (thermal) free jet (supersonic) molecular beams are used in a range of applications from surface science and surface deposition to quantum coherence and gas kinetics experiments. A free jet molecular beam is created by a gas expansion from a high pressure reservoir through a small aperture (nozzle). The nozzle typically has a diameter of 2-20 ?m. The central part of the beam is selected using a skimmer, typically up to 500 ?m in diameter. Recent years have seen the introduction of highly spatially confined beam sources based on micrometer skimmers and micrometer or even sub-micrometer nozzles. Such sources have been applied, for example, in the investigation of superfluidity and in neutral helium microscopy. However, up till now no source design allowing the <span class="hlt">precise</span> <span class="hlt">positioning</span> of the micro-skimmer relative to the nozzle has been available. This is an important issue because the relative <span class="hlt">position</span> of skimmer and nozzle can influence the beam properties considerably. Here we present the design and implementation of a new molecular beam source, which allows an automatized, 50 nm <span class="hlt">precision</span> <span class="hlt">positioning</span> of the skimmer relative to the nozzle. The source is liquid nitrogen cooled and the temperature can be controlled between 110 K and 350 K with a temperature fluctuation of less than ±0.1 K over several hours. Beam intensity measurements using a 5 ?m nozzle and a skimmer 5 ?m in diameter are presented for stagnation pressures po in the range 3-180 bars. A 2D beam profile scan, using a 9.5 ?m skimmer and a 5 ?m nozzle is presented as a further documentation of the versatility of the new design and as an illustration of the influence of the relative skimmer-nozzle <span class="hlt">position</span> on the beam properties. PMID:24089819</p> <div class="credits"> <p class="dwt_author">Eder, S D; Samelin, B; Bracco, G; Ansperger, K; Holst, B</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">160</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/1410.4919v1"> <span id="translatedtitle">On the relation between reliable computation time, float-<span class="hlt">point</span> <span class="hlt">precision</span> and the Lyapunov exponent in chaotic systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">The relation among reliable computation time, Tc, float-<span class="hlt">point</span> <span class="hlt">precision</span>, K, and the Lyapunov exponent, {\\lambda}, is obtained as Tc= (lnB/{\\lambda})K+C, where B is the base of the float-<span class="hlt">point</span> system and C is a constant dependent only on the chaotic equation. The equation shows good agreement with numerical experimental results, especially the scale factors.</p> <div class="credits"> <p class="dwt_author">PengFei Wang; JianPing Li</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-10-18</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_7");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' 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showDiv("page_10");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">161</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1997NIMPA.398..399N"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">positioning</span> of SuperKamiokande with GPS for a long-baseline neutrino oscillation experiment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A <span class="hlt">positioning</span> of the neutrino detector SuperKamiokande (SK) was made for a long-baseline neutrino oscillation experiment planned at KEK. For <span class="hlt">positioning</span>, Global <span class="hlt">Positioning</span> System (GPS) was employed. It has been demonstrated that GPS is of practical use for measuring the <span class="hlt">positions</span> of SK and KEK, being 250 km distance from each other, to a better resolution. The geodetic coordinates at the SK center were obtained to be Lat. 36°25'32.5862'' N., Long. 137°18'37.1241'' E., H. 371.839 m in the global ellipsoidal coordinate system, WGS-84. The obtained coordinates are based on the coordinates given at a triangulation <span class="hlt">point</span> at the KEK site. The present work will be fed back for constructing the neutrino beam line.</p> <div class="credits"> <p class="dwt_author">Noumi, H.; Kurodai, M.; Ieiri, M.; Ishii, H.; Kasa, H.; Katoh, Y.; Minakawa, M.; Nakamura, K.; Nishikawa, K.; Suzuki, Y.; Takasaki, M.; Tanaka, K. H.; Yamanoi, Y.; Yoshimura, K.</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">162</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19760004131&hterms=truncated+multipliers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dtruncated%2Bmultipliers"> <span id="translatedtitle">A study of attitude control concepts for <span class="hlt">precision-pointing</span> non-rigid spacecraft</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Attitude control concepts for use onboard structurally nonrigid spacecraft that must be <span class="hlt">pointed</span> with great <span class="hlt">precision</span> are examined. The task of determining the eigenproperties of a system of linear time-invariant equations (in terms of hybrid coordinates) representing the attitude motion of a flexible spacecraft is discussed. Literal characteristics are developed for the associated eigenvalues and eigenvectors of the system. A method is presented for determining the poles and zeros of the transfer function describing the attitude dynamics of a flexible spacecraft characterized by hybrid coordinate equations. Alterations are made to linear regulator and observer theory to accommodate modeling errors. The results show that a model error vector, which evolves from an error system, can be added to a reduced system model, estimated by an observer, and used by the control law to render the system less sensitive to uncertain magnitudes and phase relations of truncated modes and external disturbance effects. A hybrid coordinate formulation using the provided assumed mode shapes, rather than incorporating the usual finite element approach is provided.</p> <div class="credits"> <p class="dwt_author">Likins, P. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">1975-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">163</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005SPIE.6052E..0JS"> <span id="translatedtitle">Design of a <span class="hlt">precision</span> rotary-linear dual-axis <span class="hlt">positioning</span> system with a surface encoder</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This paper presents a prototype rotary/linear dual-axis <span class="hlt">positioning</span> system consisting of a ?-Z actuator and a rotary-linear angle sensor. In the system, an aluminum rotor (moving element) can be moved along and rotated about the axis (Z) of a ceramic cylinder (driving rod). The ?-Z actuator is composed of a Z-piezoelectric actuator (maximum stroke: 12 ?m) for linear motion, two ?-piezoelectric actuators (maximum strokes: 9.1 ?m) with an added weight for rotation, a driving rod and a rotor. The two ?-piezoelectric actuators with the added weight are attached to the driving rod via a clamping device made with steel. The inner face of the rotor is made contact to the driving rod with a certain friction force. The linear-axis <span class="hlt">positioning</span> employs the smooth impact drive mechanism to achieve a large stroke by applying a periodic saw-toothed motion from the Z-piezoelectric actuator to the rotor via the driving rod. Sinusoidal motions are applied to the ?-piezoelectric actuators for rotary <span class="hlt">positioning</span>, which is with a different mechanism form the smooth impact drive mechanism. The stroke of the prototype system along the Z-axis, which is limited by the length of the cylinder, is designed to be 10mm and there is no limitation in the rotary motion. The <span class="hlt">positioning</span> resolution and maximum speed along the Z-direction are approximately a few nanometers and 2.4mm/sec, respectively. The maximum revolution speed is approximately 50 rpm. An optical surface encoder is also designed for <span class="hlt">precision</span> <span class="hlt">positioning</span> of the rotor.</p> <div class="credits"> <p class="dwt_author">Sato, Shinji; Gao, Wei; Kiyono, Satoshi</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">164</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014ArtSa..49...21O"> <span id="translatedtitle">GNSS <span class="hlt">positioning</span> algorithms using methods of reference <span class="hlt">point</span> indicators</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The GNSS standard <span class="hlt">positioning</span> solution determines the coordinates of the GNSS receiver and the receiver clock offset from measurements of at least four pseudoranges. For GNSS <span class="hlt">positioning</span>, a direct solution was derived for five and ten observed satellites without linearisation of the observation equations and application of the least squares method. The article presents the basic principles of methods for solving the <span class="hlt">positioning</span> problem, the formulas and their derivation. The numerical examples with simulated pseudorange data confirm the correct performance of the proposed algorithm. The presented algorithms should be further tested with real measurements in other domains of <span class="hlt">positioning</span> and navigation as well.</p> <div class="credits"> <p class="dwt_author">Oszczak, Bartlomiej</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">165</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.comm.utoronto.ca/~valaee/Publications/10-Feng-Infocom.pdf"> <span id="translatedtitle">Compressive Sensing Based <span class="hlt">Positioning</span> Using RSS of WLAN Access <span class="hlt">Points</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">sensing, Affinity propagation, WLANs I. INTRODUCTION Recent technological achievements have made it fea <span class="hlt">positioning</span> system consists of two steps: coarse localization by exploiting affinity prop- agation, and fine propagation model to formulate the RSS-<span class="hlt">position</span> relationship [7]. However, these models are unreliable due</p> <div class="credits"> <p class="dwt_author">Valaee, Shahrokh</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">166</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19910070141&hterms=reference+frame&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dreference%2Bframe"> <span id="translatedtitle"><span class="hlt">POINTS</span> - A global reference frame opportunity. [<span class="hlt">Precision</span> Optical Interferometer in Space</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><span class="hlt">POINTS</span> is a space-based optical astrometric interferometer capable of measuring the angular separation of two stars about 90 degrees apart with 5-microarcsec nominal accuracy . During the intended ten-year mission, a repeated survey of a few hundred targets over the whole sky, including a few bright quasars, establish a 'rigid' reference grid with 0.5 microarcsec <span class="hlt">position</span> uncertainties. At that level, the grid is free of regional biases and tied to the extra-Galactic frame that is the present best candidate for an inertial frame. <span class="hlt">POINTS</span> will also determine parallaxes and annual proper motions at about the same level. Further, the planetary ephemeris frame is tied through stellar aberration to the grid at about 300 microarcsec. Additional targets of interest, to a limiting magnitude of greater than 20, are observed relative to the grid, yielding determinations with uncertainties depending on the observing schedule. Measurement at the microarcsec/year level of the apparent relative velocities of quasars that are widely separated on the sky severely test the assumption of cosmological quasar distances and may also constrain models of the early universe.</p> <div class="credits"> <p class="dwt_author">Chandler, J. F.; Reasenberg, R. D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">167</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/1748669"> <span id="translatedtitle">Experiments of Laser <span class="hlt">Pointing</span> Stability in Air and in Vacuum to Validate Micrometric <span class="hlt">Positioning</span> Sensor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Aligning accelerator components over 200m with 10 ?m accuracy is a challenging task within the Compact Linear Collider (CLIC) study. A solution based on laser beam in vacuum as straight line reference is proposed. The <span class="hlt">positions</span> of the accelerator’s components are measured with respect to the laser beam by sensors made of camera/shutter assemblies. To validate these sensors, laser <span class="hlt">pointing</span> stability has to be studied over 200m. We perform experiments in air and in vacuum in order to know how laser <span class="hlt">pointing</span> stability varies with the distance of propagation and with the environment. The experiments show that the standard deviations of the laser spot coordinates increase with the distance of propagation. They also show that the standard deviations are much smaller in vacuum (8 ?m at 35m) than in air (2000 ?m at 200m). Our experiment validates the concept of laser beam in vacuum with camera/shutter assembly for micrometric <span class="hlt">positioning</span> over 35m. It also gives an estimation of the achievable <span class="hlt">precision</span>.</p> <div class="credits"> <p class="dwt_author">Stern, G; Piedigrossi, D; Sandomierski, J; Sosin, M; Geiger, A; Guillaume, S</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">168</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014PhRvD..90c5023K"> <span id="translatedtitle"><span class="hlt">Precise</span> focus <span class="hlt">point</span> scenario for a natural Higgs boson in the MSSM</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A small Higgs mass parameter mhu2 can be insensitive to various trial heavy stop masses, if a universal soft squared mass is assumed for the chiral superpartners and the Higgs boson at the grand unification (GUT) scale, and a focus <span class="hlt">point</span> (FP) of mhu2 appears around the stop mass scale. The challenges in the FP scenario are (1) a too heavy stop mass (?5 TeV) needed for the 126 GeV Higgs mass and (2) the too high gluino mass bound (?1.4 TeV). For a successful FP scenario, we consider (1) a superheavy right-hand (RH) neutrino and (2) the first and second generations of hierarchically heavier chiral superpartners. The RH neutrino can move a FP in the higher energy direction in the space of (Q ,mhu2(Q)), where Q denotes the renormalization scale. On the other hand, the hierarchically heavier chiral superpartners can lift up a FP in that space through two-loop gauge interactions. <span class="hlt">Precise</span> focusing of mhu2(Q) is achieved with the RH neutrino mass of ˜1014 GeV together with an order one (0.9-1.2) Yukawa coupling to the Higgs boson, and the hierarchically heavy masses of 15-20 TeV for the heavier generations of superpartners, when the U(1)R breaking soft parameters m1/2 and A0 are set to be 1 TeV at the GUT scale. Those values can naturally explain the small neutrino mass through the seesaw mechanism, and suppress the flavor violating processes in supersymmetric models.</p> <div class="credits"> <p class="dwt_author">Kyae, Bumseok; Shin, Chang Sub</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">169</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/1403.6527v3"> <span id="translatedtitle"><span class="hlt">Precise</span> focus <span class="hlt">point</span> scenario for a natural Higgs boson in the MSSM</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">A small Higgs mass parameter m_{h_u}^2 can be insensitive to various trial heavy stop masses, if a universal soft squared mass is assumed for the chiral superpartners and the Higgs boson at the grand unification (GUT) scale, and a focus <span class="hlt">point</span> (FP) of m_{h_u}^2 appears around the stop mass scale. The challenges in the FP scenario are (1) a too heavy stop mass (~ 5 TeV) needed for the 126 GeV Higgs mass and (2) the too high gluino mass bound (> 1.4 TeV). For a successful FP scenario, we consider (1) a superheavy right-hand (RH) neutrino and (2) the first and second generations of hierarchically heavier chiral superpartners. The RH neutrino can move a FP in the higher energy direction in the space of (Q, m_{h_u}^2(Q)), where Q denotes the renormalization scale. On the other hand, the hierarchically heavier chiral superpartners can lift up a FP in that space through two-loop gauge interactions. <span class="hlt">Precise</span> focusing of m_{h_u}^2(Q) is achieved with the RH neutrino mass of ~ 10^{14} GeV together with an order one (0.9-1.2) Dirac Yukawa coupling to the Higgs boson, and the hierarchically heavy masses of 15-20 TeV for the heavier generations of superpartners, when the U(1)_R breaking soft parameters, m_{1/2} and A_0 are set to be 1 TeV at the GUT scale. Those values can naturally explain the small neutrino mass through the seesaw mechanism, and suppress the flavor violating processes in supersymmetric models.</p> <div class="credits"> <p class="dwt_author">Bumseok Kyae; Chang Sub Shin</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-03-25</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">170</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2001PhDT........52E"> <span id="translatedtitle"><span class="hlt">Precision</span> spacecraft rendezvous using global <span class="hlt">positioning</span> system: An integrated hardware approach</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The objective of this dissertation is to develop a <span class="hlt">precision</span> rendezvous methodology for Earth orbiting spacecraft utilizing the Global <span class="hlt">Positioning</span> System (GPS). A GPS receiver is placed on each space vehicle and a communication link is used to pass GPS measurements from the target to the chaser spacecraft. The integrated navigation and guidance system resides on the chaser vehicle. The fundamental component of the measurement processing navigation system is a real-time recursive extended Kalman filter (EKF). The navigation system provides absolute and relative <span class="hlt">position</span> and velocity estimates that are used by the on-board guidance for computing rendezvous maneuvers without ground support. To achieve very <span class="hlt">precise</span> relative navigation, the filter processes double-difference carrier phase measurements. The unavoidable double-difference integer ambiguity is part of the filter state and is treated as a real number. The Global Simulation Systems (GSS) STR4760 GPS signal generator was used to perform open-loop simulations to evaluate the relative navigation filter performance in conjunction with a commercial, user programmable GPS receiver that was extensively modified for space applications. Open-loop implies that no on-board targeted rendezvous maneuvers are executed. The open-loop simulation investigations show that a 5 cm or less relative <span class="hlt">positioning</span> accuracy and about a 1 mm/s relative velocity estimation accuracy are achievable. With these highly accurate relative navigation results, the notion of autonomous space rendezvous becomes plausible. One of the key contributions of this research involves the development of a hardware-in-the loop (HWIL) GPS test facility, which is capable of performing active closed-loop scenarios in real-time mode with actual GPS signal processing hardware. The GSS STR4760 is a closed-loop simulation system capable with the GSS STR4762 Remote Control option. The HWIL GPS test facility was constructed and configured to evaluate the newly developed relative navigation algorithms integrated with on-board targeting from real-time navigation data. This is the first time this type of hardware for closed-loop spacecraft rendezvous experiments has been reported.</p> <div class="credits"> <p class="dwt_author">Ebinuma, Takuji</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">171</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007PhDT........93Y"> <span id="translatedtitle">Modeling, actuator optimization, and simultaneous <span class="hlt">precision</span> <span class="hlt">positioning</span> and vibration suppression of smart composite panels</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">To improve the fuel consumption of a satellite, maintain the <span class="hlt">position</span> and orientation and eliminate the unwanted thruster vibration, intelligent composite structure technology was proposed in the ADPICAS (Adaptive Damping and <span class="hlt">Positioning</span> using Intelligent Composite Active Structures) project funded by the ONR (Office of Naval Research) in collaboration with the NRL (Naval Research Laboratory) in 2000. This dissertation introduces the author's research achievements in developing smart composite panels for the ADPICAS project, including modeling, actuator optimization, and vibration control. The method of separation of variables is presented to derive the analytical shape functions for complex composite structures with asymmetric constraints, i.e., the 2-D Adaptive Composite Circular Plate (ACCP) in cylindrical coordinates and the 3-D Adaptive Composite Satellite Dish (ACSD) in spherical coordinates. Following these solutions, two modeling approaches are developed to obtain the models of adaptive composite panels including an adaptive composite beam, the ACCP, and the ACSD. One model approach is to employ the Lagrange-Rayleigh-Ritz method based on the developed analytical shape functions. Meanwhile, the transfer function estimation technique, combining the finite element analyses, is applied to obtain the numerical model of the composite panels. Aiming at improving the actuation efficiency, a Genetic Algorithm is presented to optimize the piezoelectric actuator placement on the composite panels. Taking the inertia and stiffness characteristics of the piezoelectric actuators into account, this algorithm defines the performance index as a weighted summation of control error and control energy consumption, and obtained the optimal solution that minimizes the performance index. Furthermore, an adaptive disturbance observer/feed-forward (ADOB/FF) controller is proposed to achieve simultaneous <span class="hlt">precision</span> <span class="hlt">positioning</span> and vibration suppression of the adaptive composite panels. Numerical simulations and experiments are conducted. The optimal piezoelectric actuator configuration saves the control energy and reduces vibration of the composite panels substantially. The simulations and experiments show that the ADOB/FF provides a robust performance against the system parameter perturbations and environmental disturbances.</p> <div class="credits"> <p class="dwt_author">Yan, Su</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">172</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013SPIE.8590E..0LB"> <span id="translatedtitle">The double-helix <span class="hlt">point</span> spread function enables <span class="hlt">precise</span> and accurate measurement of 3D single-molecule localization and orientation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Single-molecule-based super-resolution fluorescence microscopy has recently been developed to surpass the diffraction limit by roughly an order of magnitude. These methods depend on the ability to <span class="hlt">precisely</span> and accurately measure the <span class="hlt">position</span> of a single-molecule emitter, typically by fitting its emission pattern to a symmetric estimator (e.g. centroid or 2D Gaussian). However, single-molecule emission patterns are not isotropic, and depend highly on the orientation of the molecule's transition dipole moment, as well as its z-<span class="hlt">position</span>. Failure to account for this fact can result in localization errors on the order of tens of nm for in-focus images, and ~50-200 nm for molecules at modest defocus. The latter range becomes especially important for three-dimensional (3D) single-molecule super-resolution techniques, which typically employ depths-of-field of up to ~2 ?m. To address this issue we report the simultaneous measurement of <span class="hlt">precise</span> and accurate 3D single-molecule <span class="hlt">position</span> and 3D dipole orientation using the Double-Helix <span class="hlt">Point</span> Spread Function (DH-PSF) microscope. We are thus able to significantly improve dipole-induced <span class="hlt">position</span> errors, reducing standard deviations in lateral localization from ~2x worse than photon-limited <span class="hlt">precision</span> (48 nm vs. 25 nm) to within 5 nm of photon-limited <span class="hlt">precision</span>. Furthermore, by averaging many estimations of orientation we are able to improve from a lateral standard deviation of 116 nm (~4x worse than the <span class="hlt">precision</span>, 28 nm) to 34 nm (within 6 nm).</p> <div class="credits"> <p class="dwt_author">Backlund, Mikael P.; Lew, Matthew D.; Backer, Adam S.; Sahl, Steffen J.; Grover, Ginni; Agrawal, Anurag; Piestun, Rafael; Moerner, W. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">173</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009JMiMi..19f5027B"> <span id="translatedtitle">MEMS-based clamp with a passive hold function for <span class="hlt">precision</span> <span class="hlt">position</span> retaining of micro manipulators</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this paper the design, modeling and fabrication of a <span class="hlt">precision</span> MEMS-based clamp with a relatively large clamping force are presented. The purpose of the clamp is to mechanically fix a six-degree-of-freedom (DOF) MEMS-based sample manipulator (Brouwer et al J. Int. Soc. Precis. Eng. Nanotechnol. submitted) once the sample has been <span class="hlt">positioned</span> in all DOFs. The clamping force is generated by a rotational electrostatic comb-drive actuator and can be latched passively by a parallel plate type electrostatically driven locking device. The clamp design is based on the principles of exact constraint design, resulting in a high actuation compliance (flexibility) combined with a high suspension stiffness. Therefore, a relatively large blocking force of 1.4 mN in relation to the used area of 1.8 mm2 is obtained. The fabrication is based on silicon bulk micromachining technology and combines a high-aspect-ratio deep reactive ion etching (DRIE), conformal deposition of low-pressure chemical vapor deposition (LPCVD) silicon nitride and an anisotropic potassium hydroxide (KOH) backside etching technology. Special attention is given to void reduction of SixNy trench isolation and reduction of heating phenomena during front-side release etching. Guidelines are given for the applied process. Measurements showed that the clamp was able to fix, hold and release a test actuator. The dynamic behavior was in good agreement with the modal analysis.</p> <div class="credits"> <p class="dwt_author">Brouwer, D. M.; de Jong, B. R.; de Boer, M. J.; Jansen, H. V.; van Dijk, J.; Krijnen, G. J. M.; Soemers, H. M. J. R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">174</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/4273889"> <span id="translatedtitle">Behavioral Synthesis of Double-<span class="hlt">Precision</span> Floating-<span class="hlt">Point</span> Adders with Function-Level Transformations: A Case Study</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Recently, the continuously growing capacity of FPGAs has enabled us to place floating-<span class="hlt">point</span> arithmetic IPs on FPGAs. The required\\u000a area for floating-<span class="hlt">point</span> computations, however, is still high. This paper presents a case study on behavioral synthesis of\\u000a double-<span class="hlt">precision</span> floating-<span class="hlt">point</span> adders and adder\\/subtracters for FPGAs. With function-level transformations, we design totally\\u000a 15 adders and 21 adder\\/subtracters from addition and subtraction functions</p> <div class="credits"> <p class="dwt_author">Yuko Hara; Hiroyuki Tomiyama; Shinya Honda; Hiroaki Takada; Katsuya Ishii</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">175</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/31186gw5u2057845.pdf"> <span id="translatedtitle">Semi-robotic 6 degree of freedom <span class="hlt">positioning</span> for intracranial high <span class="hlt">precision</span> radiotherapy; first phantom and clinical results</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">BACKGROUND: To introduce a novel method of patient <span class="hlt">positioning</span> for high <span class="hlt">precision</span> intracranial radiotherapy. METHODS: An infrared(IR)-array, reproducibly attached to the patient via a vacuum-mouthpiece(vMP) and connected to the table via a 6 degree-of-freedom(DoF) mechanical arm serves as <span class="hlt">positioning</span> and fixation system. After IR-based manual prepositioning to rough treatment <span class="hlt">position</span> and fixation of the mechanical arm, a cone-beam CT(CBCT) is</p> <div class="credits"> <p class="dwt_author">Jürgen Wilbert; Matthias Guckenberger; Bülent Polat; Otto Sauer; Michael Vogele; Michael Flentje; Reinhart A Sweeney</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">176</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3871121"> <span id="translatedtitle">A Kalman Filter Implementation for <span class="hlt">Precision</span> Improvement in Low-Cost GPS <span class="hlt">Positioning</span> of Tractors</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Low-cost GPS receivers provide geodetic <span class="hlt">positioning</span> information using the NMEA protocol, usually with eight digits for latitude and nine digits for longitude. When these geodetic coordinates are converted into Cartesian coordinates, the <span class="hlt">positions</span> fit in a quantization grid of some decimeters in size, the dimensions of which vary depending on the <span class="hlt">point</span> of the terrestrial surface. The aim of this study is to reduce the quantization errors of some low-cost GPS receivers by using a Kalman filter. Kinematic tractor model equations were employed to particularize the filter, which was tuned by applying Monte Carlo techniques to eighteen straight trajectories, to select the covariance matrices that produced the lowest Root Mean Square Error in these trajectories. Filter performance was tested by using straight tractor paths, which were either simulated or real trajectories acquired by a GPS receiver. The results show that the filter can reduce the quantization error in distance by around 43%. Moreover, it reduces the standard deviation of the heading by 75%. Data suggest that the proposed filter can satisfactorily preprocess the low-cost GPS receiver data when used in an assistance guidance GPS system for tractors. It could also be useful to smooth tractor GPS trajectories that are sharpened when the tractor moves over rough terrain. PMID:24217355</p> <div class="credits"> <p class="dwt_author">Gomez-Gil, Jaime; Ruiz-Gonzalez, Ruben; Alonso-Garcia, Sergio; Gomez-Gil, Francisco Javier</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">177</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50587690"> <span id="translatedtitle">High <span class="hlt">Precision</span> Robust Controller Design for PMSM Servo System with Multi-operating-<span class="hlt">points</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this paper we propose a high <span class="hlt">precision</span> robust controller design method for surface mounted PMSM servo system. Feedback linearization method is first applied to transfer the motor plant into a linearized model with an equivalent disturbance. Then a robust controller is designed to compensate the equivalent disturbance. Although some parameters of the control system may deviate seriously from the</p> <div class="credits"> <p class="dwt_author">Yang Shusheng; Zhong Yisheng</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">178</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19890018511&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">pointing</span> compensation for DSN antennas with optical distance measuring sensors</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The <span class="hlt">pointing</span> control loops of Deep Space Network (DSN) antennas do not account for unmodeled deflections of the primary and secondary reflectors. As a result, structural distortions due to unpredictable environmental loads can result in uncompensated boresight shifts which degrade <span class="hlt">pointing</span> accuracy. The design proposed here can provide real-time bias commands to the <span class="hlt">pointing</span> control system to compensate for environmental effects on <span class="hlt">pointing</span> performance. The bias commands can be computed in real time from optically measured deflections at a number of <span class="hlt">points</span> on the primary and secondary reflectors. Computer simulations with a reduced-order finite-element model of a DSN antenna validate the concept and lead to a proposed design by which a ten-to-one reduction in <span class="hlt">pointing</span> uncertainty can be achieved under nominal uncertainty conditions.</p> <div class="credits"> <p class="dwt_author">Scheid, R. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">179</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19890018512&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">The effects of atmospheric turbulence on <span class="hlt">precision</span> optical measurements used for antenna-<span class="hlt">pointing</span> compensation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Blind <span class="hlt">pointing</span> of the Deep Space Network (DSN) 70-meter antennas can be improved if distortions of the antenna structure caused by unpredictable environmental loads can be measured in real-time, and the resulting boresight shifts evaluated and incorporated into the <span class="hlt">pointing</span> control loops. The measurement configuration of a proposed <span class="hlt">pointing</span> compensation system includes an optical range sensor that measures distances to selected <span class="hlt">points</span> on the antenna surface. The effect of atmospheric turbulence on the accuracy of optical distance measurements and a method to make in-situ determinations of turbulence-induced measurement errors are discussed.</p> <div class="credits"> <p class="dwt_author">Nerheim, N.</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">180</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20060041208&hterms=tectonic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dtectonic"> <span id="translatedtitle"><span class="hlt">Precise</span> GPS/Acoustic <span class="hlt">Positioning</span> of Seafloor Reference <span class="hlt">Points</span> for Tectonic Studies</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Global networks for crustal strain measurement provide important constraints for studies of tectonic plate motion and deformation. To date, crustal strain measurements have been possible only in terrestrial settings: on continental plates and island sites within oceanic plates.</p> <div class="credits"> <p class="dwt_author">Spiess, F. N.; Chadwell, C.; Hildebrand, J. A.; Young, L. E.; Purcell, G. H., Jr.; Dragert, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_8");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return 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onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_11");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">181</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.scg.ulaval.ca/gps-rs/pdf/NorvegianCitation%20Masteroppgave_Vadder_Halvor.pdf"> <span id="translatedtitle">PPP -Test av online tjenester <span class="hlt">Precise</span> <span class="hlt">point</span> <span class="hlt">positioning</span> -online processing services</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">medstudenter p�a lesesalen for faglig hjelp og motivasjon underveis. iii #12;Sammendrag Denne oppgaven tar�ren. Det best�ar av frie elektroner og ioner og varierer etter tid og lokasjon. GPS- signalet vil gjennom</p> <div class="credits"> <p class="dwt_author">Santerre, Rock</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">182</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dspace.mit.edu/handle/1721.1/32366"> <span id="translatedtitle">High-<span class="hlt">precision</span> <span class="hlt">position</span> control of a heavy-lift manipulator in a dynamic environment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">This thesis considers the control of a heavy-lift serial manipulator operating on the deck of a large ocean vessel. This application presents a unique challenge for high- <span class="hlt">precision</span> control because the system must contend ...</p> <div class="credits"> <p class="dwt_author">Garretson, Justin R. (Justin Richard)</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">183</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/2193077"> <span id="translatedtitle">A design of high speed double <span class="hlt">precision</span> floating <span class="hlt">point</span> adder using macro modules</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Based on SMIC 0.18 ?m 1.8v six-layer-metal CMOS process, we implement a 64-bit high speed pipelined floating <span class="hlt">point</span> adder which satisfied IEEE 754 standard. After the critical path analysis of the pipelined structure, we custom design three macro modules in order to reduce critical path delay. After placement in datapath style and routing, we implement the layout of floating <span class="hlt">point</span></p> <div class="credits"> <p class="dwt_author">Chi Huang; Xinyu Wu; Jinmei Lai; Chengshou Sun; Gang Li</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">184</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24735503"> <span id="translatedtitle">The effect of patient <span class="hlt">positioning</span> on the <span class="hlt">precision</span> of model-based radiostereometric analysis.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">A repeatable method for in vivo and in vitro measurement of polyethylene wear in total knee replacement (TKA) is needed. This research examines the model-based radiostereometric analysis' (MBRSA) in vitro <span class="hlt">precision</span> under different patient-radiograph orientations and flexion angles of the knee using a TKA phantom. Anterior-posterior and medial-lateral imaging orientations showed the highest <span class="hlt">precision</span>; better than 0.036mm (3-dimensional translation) and 0.089° (3-dimensional rotation). Flexion of the knee did not affect MBRSA <span class="hlt">precision</span>. Medial-lateral imaging is advantageous as it allows for flexion of the knee joint during an RSA examination, thus providing greater information for wear measurement. PMID:24735503</p> <div class="credits"> <p class="dwt_author">Gascoyne, Trevor C; Morrison, Jason B; Turgeon, Thomas R</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">185</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19730023601&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">A laboratory simulation of a single-axis dual-level <span class="hlt">precision</span> <span class="hlt">pointing</span> system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The laboratory simulation of a scaled single-axis dual-level control system for a large space telescope is demonstrated. The dual-level control system consists of a coarse-body-<span class="hlt">pointing</span> system and a fine-<span class="hlt">pointing</span> system, which uses an image motion compensator, an image dissector tube, and digital electronics. The results of the simulation indicate that the dual-level system can be used to provide tracking capability within one-tenth of a diffraction-limited image diameter of a 3-meter f/100 telescope for stars up to a +12.3 visual magnitude.</p> <div class="credits"> <p class="dwt_author">Bullock, G. F.; Morrell, F. R.; Romanczyk, K. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1973-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">186</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20120010344&hterms=carbon+footprint&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcarbon%2Bfootprint"> <span id="translatedtitle">Impact of Footprint Diameter and Off-Nadir <span class="hlt">Pointing</span> on the <span class="hlt">Precision</span> of Canopy Height Estimates from Spaceborne Lidar</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A spaceborne lidar mission could serve multiple scientific purposes including remote sensing of ecosystem structure, carbon storage, terrestrial topography and ice sheet monitoring. The measurement requirements of these different goals will require compromises in sensor design. Footprint diameters that would be larger than optimal for vegetation studies have been proposed. Some spaceborne lidar mission designs include the possibility that a lidar sensor would share a platform with another sensor, which might require off-nadir <span class="hlt">pointing</span> at angles of up to 16 . To resolve multiple mission goals and sensor requirements, detailed knowledge of the sensitivity of sensor performance to these aspects of mission design is required. This research used a radiative transfer model to investigate the sensitivity of forest height estimates to footprint diameter, off-nadir <span class="hlt">pointing</span> and their interaction over a range of forest canopy properties. An individual-based forest model was used to simulate stands of mixed conifer forest in the Tahoe National Forest (Northern California, USA) and stands of deciduous forests in the Bartlett Experimental Forest (New Hampshire, USA). Waveforms were simulated for stands generated by a forest succession model using footprint diameters of 20 m to 70 m. Off-nadir angles of 0 to 16 were considered for a 25 m diameter footprint diameter. Footprint diameters in the range of 25 m to 30 m were optimal for estimates of maximum forest height (R(sup 2) of 0.95 and RMSE of 3 m). As expected, the contribution of vegetation height to the vertical extent of the waveform decreased with larger footprints, while the contribution of terrain slope increased. <span class="hlt">Precision</span> of estimates decreased with an increasing off-nadir <span class="hlt">pointing</span> angle, but off-nadir <span class="hlt">pointing</span> had less impact on height estimates in deciduous forests than in coniferous forests. When <span class="hlt">pointing</span> off-nadir, the decrease in <span class="hlt">precision</span> was dependent on local incidence angle (the angle between the off-nadir beam and a line normal to the terrain surface) which is dependent on the off-nadir <span class="hlt">pointing</span> angle, terrain slope, and the difference between the laser <span class="hlt">pointing</span> azimuth and terrain aspect; the effect was larger when the sensor was aligned with the terrain azimuth but when aspect and azimuth are opposed, there was virtually no effect on R2 or RMSE. A second effect of off-nadir <span class="hlt">pointing</span> is that the laser beam will intersect individual crowns and the canopy as a whole from a different angle which had a distinct effect on the <span class="hlt">precision</span> of lidar estimates of height, decreasing R2 and increasing RMSE, although the effect was most pronounced for coniferous crowns.</p> <div class="credits"> <p class="dwt_author">Pang, Yong; Lefskky, Michael; Sun, Guoqing; Ranson, Jon</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">187</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20060012286&hterms=cooperative+learning&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcooperative%2Blearning"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">Pointing</span> Control to and Accurate Target Estimation of a Non-Cooperative Vehicle</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">In 2004, NASA began investigating a robotic servicing mission for the Hubble Space Telescope (HST). Such a mission would not only require estimates of the HST attitude and rates in order to achieve capture by the proposed Hubble Robotic Vehicle (HRV), but also <span class="hlt">precision</span> control to achieve the desired rate and maintain the orientation to successfully dock with HST. To generalize the situation, HST is the target vehicle and HRV is the chaser. This work presents a nonlinear approach for estimating the body rates of a non-cooperative target vehicle, and coupling this estimation to a control scheme. Non-cooperative in this context relates to the target vehicle no longer having the ability to maintain attitude control or transmit attitude knowledge.</p> <div class="credits"> <p class="dwt_author">VanEepoel, John; Thienel, Julie; Sanner, Robert M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">188</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54708985"> <span id="translatedtitle"><span class="hlt">Precision</span> telescope <span class="hlt">pointing</span> and spacecraft vibration isolation for the Terrestrial Planet Finder Coronagraph</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Terrestrial Planet Finder Coronagraph is a visible-light coronagraph to detect planets that are orbiting within the Habitable Zone of stars. The coronagraph instrument must achieve a contrast ratio stability of 2e-11 in order to achieve planet detection. This places stringent requirements on several spacecraft subsystems, such as <span class="hlt">pointing</span> stability and structural vibration of the instrument in the presence of</p> <div class="credits"> <p class="dwt_author">Larry Dewell; Nelson Pedreiro; Carl Blaurock; Kuo-Chia Liu; James Alexander; Marie Levine</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">189</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/27059572"> <span id="translatedtitle">Sensorless Maximum Power <span class="hlt">Point</span> Tracking of Wind by DFIG Using Rotor <span class="hlt">Position</span> Phase Lock Loop (PLL)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper presents an invention, the rotor <span class="hlt">position</span> phase lock loop (PLL), which enables maximum power <span class="hlt">point</span> (MPPT) tracking of wind by doubly-fed induction generators without needing a tachometer, an absolute <span class="hlt">position</span> encoder, or an anemometer. The rotor <span class="hlt">position</span> PLL is parameter variation insensitive, requiring only an estimate of the magnetization inductance for it to operate. It is also insensitive</p> <div class="credits"> <p class="dwt_author">Baike Shen; Bakari Mwinyiwiwa; Yongzheng Zhang; Boon-Teck Ooi</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">190</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19860050669&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">The design of a <span class="hlt">precision</span> <span class="hlt">pointing</span> contol system for the Space Infrared Telescope Facility</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The design and performance simulation of the Space Infrared Telescope Facility <span class="hlt">pointing</span> and control system are described. The system design is constrained by such considerations as image stability, maneuver capability, cryogen lifetime, and structural flexibility. The primary design driver is the requirement to rapidly execute small angle reorientations of the telescope's optical axis. The flexibility of the spacecraft was simulated using a simplified multibody model which provided an approximation of the primary bending modes. The rather conventional attitude control system design of PID type with a 0.5 Hz bandwidth was enhanced to meet the small angle maneuver requirements by the use of three techniques: (1) a feedforward loop to improve the time response; (2) torque shaping to minimize structural excitation; and (3) active image stabilization to remove residual <span class="hlt">pointing</span> error and jitter. Simulation results indicate that the system has the desired performance and can be designed using techniques and hardware well within the state-of-the-art.</p> <div class="credits"> <p class="dwt_author">Sridhar, B.; Aurbrun, J.-N.; Lorell, K. R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">191</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006GML....26..141E"> <span id="translatedtitle"><span class="hlt">Precision</span> of high-resolution multibeam echo sounding coupled with high-accuracy <span class="hlt">positioning</span> in a shallow water coastal environment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Over 4 years, repetitive bathymetric measurements of a shipwreck in the Grådyb tidal inlet channel in the Danish Wadden Sea were carried out using a state-of-the-art high-resolution multibeam echosounder (MBES) coupled with a real-time long range kinematic (LRK™) global <span class="hlt">positioning</span> system. Seven measurements during a single survey in 2003 ( n=7) revealed a horizontal and vertical <span class="hlt">precision</span> of the MBES system of ±20 and ±2 cm, respectively, at a 95% confidence level. By contrast, four annual surveys from 2002 to 2005 ( n=4) yielded a horizontal and vertical <span class="hlt">precision</span> (at 95% confidence level) of only ±30 and ±8 cm, respectively. This difference in <span class="hlt">precision</span> can be explained by three main factors: (1) the dismounting of the system between the annual surveys, (2) rougher sea conditions during the survey in 2004 and (3) the limited number of annual surveys. In general, the <span class="hlt">precision</span> achieved here did not correspond to the full potential of the MBES system, as this could certainly have been improved by an increase in coverage density (soundings/m2), achievable by reducing the survey speed of the vessel. Nevertheless, <span class="hlt">precision</span> was higher than that reported to date for earlier offshore test surveys using comparable equipment.</p> <div class="credits"> <p class="dwt_author">Ernstsen, Verner B.; Noormets, Riko; Hebbeln, Dierk; Bartholomä, Alex; Flemming, Burg W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">192</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1997RScI...68.1779F"> <span id="translatedtitle">Control of a multidegree of freedom standing wave ultrasonic motor driven <span class="hlt">precise</span> <span class="hlt">positioning</span> system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A newly developed <span class="hlt">positioning</span> system incorporating a multidegree of freedom standing wave ultrasonic motor (SWUM) is presented and its advantageous features, operating principles, and some experimental results are described. The principle of motorization is based on the conversion, through frictional contact, of a stationary bending vibration sustained in a slotted metallic resonator, into rigid body displacements. A small autonomous multidegree of freedom nanopositioner using a SWUM motor is presented for fine <span class="hlt">positioning</span> in scanning tunneling microscopy. The <span class="hlt">positioning</span> system is achieved via the simultaneous operation of two identical pulse width modulation servo-control systems, each having a laser vibrometer <span class="hlt">position</span> feedback loop. The closed loop <span class="hlt">position</span> schemes are theoretically considered and their results are demonstrated and evaluated in practice. Evaluations of experimental tests indicate that a <span class="hlt">positioning</span> resolution less than 100 nm are successfully achieved for an unlimited X-Y travel range with linear speeds between 1 mm s-1 and few cm s-1.</p> <div class="credits"> <p class="dwt_author">Ferreira, Antoine; Minotti, Patrice</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">193</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/42033686"> <span id="translatedtitle">Measuring <span class="hlt">precise</span> sea level from a buoy using the global <span class="hlt">positioning</span> system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">High-accuracy sea surface <span class="hlt">positioning</span> is required for sea floor geodesy, satellite altimeter verification, and the study of sea level. An experiment to study the feasibility of using the Global <span class="hlt">Positioning</span> System (GPS) for accurate sea surface <span class="hlt">positioning</span> was conducted. A GPS-equipped buoy (floater) was deployed off the Scripps pier at La Jolla, California during December 13-15, 1989. Two reference GPS</p> <div class="credits"> <p class="dwt_author">Christian Rocken; Thomas M. Kelecy; George H. Born; Larry E. Young; George H. Purcell; Susan Kornreich Wolf</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">194</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26947409"> <span id="translatedtitle">Factors influencing speed and <span class="hlt">precision</span> of cursor <span class="hlt">positioning</span> using a mouse</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Influencing factors on speed and accuracy of cursor <span class="hlt">positioning</span> using a mouse and the learning progress of subjects were analysed in experimental studies. 64 subjects (44 of whom were female) with an average age of about 24 years had to conduct 1200 cursor <span class="hlt">positioning</span> trials over a period of two days. The results show that the c:d-ratio, that is, the</p> <div class="credits"> <p class="dwt_author">ULRICH TRÄNKLE; DETLEF DEUTSCHMANN</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">195</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19880063752&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">pointing</span> of scientific instruments on space station: The LFGGREC perspective</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">An application of Lyapunov function-gradient-generated robustness-enhancing control (LFGGREC) is explored. The attention is directed to a reduced-complexity representation of the <span class="hlt">pointing</span> problem presented by the system composed of the Space Infrared Telescope Facility gimbaled to a space station configuration. Uncertainties include disturbance forces applied in the crew compartment area and control moments applied to adjacent scientific payloads (modeled as disturbance moments). Also included are uncertainties in gimbal friction and in the structural component of the system, as reflected in the inertia matrix, the damping matrix, and the stiffness matrix, and the effect of the ignored vibrational dynamics of the structure. The emphasis is on the adaptation of LFGGREC to this particular configuration and on the robustness analysis.</p> <div class="credits"> <p class="dwt_author">Blackwell, C. C.; Sirlin, S. W.; Laskin, R. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">196</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003AGUFM.G41B0034R"> <span id="translatedtitle">An Evaluation of VLBI Observations for the <span class="hlt">Precise</span> <span class="hlt">Positioning</span> of the NOZOMI Spacecraft</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We performed more than 30 VLBI experiments for the NOZOMI spacecraft navigation from September 2002 until July 2003. NOZOMI, which means ``Hope'' in Japanese, is the Japan's first Mars probe developed and launched by the Institute of Space and Astronautical Science (ISAS). NOZOMI was originally scheduled to reach its destination in October 1999. However, NOZOMI had to be forced to make extra maneuver due to malfunction of a thruster valve during the powered earth swing-by. As a result, it was found that NOZOMI no longer had enough fuel to inject itself into its scheduled orbit on arrival at Mars. Fortunately, the ISAS mission analysis team succeeded to reschedule its flight plan to meet both fuel and observation conditions. According to the new trajectory strategy, NOZOMI's arrival at Mars is scheduled in the middle of December 2003 through two additional earth swingbys in December 2002 and June 2003. Our main concern was to determine the NOZOMI orbit just before the second earth swingby on June 19, 2003. It was significantly important to get the timing to maneuver the NOZOMI before the swingby. ISAS scientists were afraid that the range and range rate (R&RR) orbit determination might not be available because it was difficult to <span class="hlt">point</span> the high-gain antenna mounted the spacecraft toward the earth during the period between two swingby events. So we started to support the orbit determination of the NOZOMI using differential VLBI technique since September 2002. These VLBI experiments are also aimed to establish the <span class="hlt">positioning</span> technology for the interplanetary spacecrafts in realtime. We use nine VLBI antennas in Japan to carry out the VLBI experiments at X-band. Algonquin 46-m of the Space Geodynamics Laboratory (SGL) of CRESTech also participated in the several experiments. We equipped the state of the art ``K5 VLBI system'' to these stations. The K5 system is the multiple PC-based VLBI system equipped with a specific PCI-bus board on the FreeBSD and Linux operating system. The K5 system includes the original software packages which are data sampling and acquisition, real-time IP data transmission, and correlation analysis. For the purpose of analyzing the VLBI observables we are developing the specific VLBI delay model for finite distance radio source. The model is already implemented in the VLBI software package. The package will include the VLBI observation scheduling to take account of the passage of the spacecraft near the quasar line of sight and the propagation delay estimating for the ionosphere and the neutral atmosphere. We can successfully detect fringes of NOZOMI range signal for several baselines using software correlation in spite of weak and narrow-bandwidth signal. We provided 15 VLBI group delay data sets to ISAS to support the orbit determination at the end of May 2003. On the other hand, ISAS scientists have fortunately succeeded to determine the NOZOMI orbit using R&RR observables at the end of May 2003. Preliminary results demonstrate that the VLBI delay residuals are consistent with R&RR observables. However, the rms scatter between them are relatively large up to several tens nanoseconds. We are now evaluating our VLBI data sets by comparing with the R&RR results.</p> <div class="credits"> <p class="dwt_author">Ryuichi, I.; Mamoru, S.; Hiroo, O.; Yasuhiro, K.; Tetsuro, K.; Takafumi, O.; Makoto, Y.; Nozomi Dvlbi Group,.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">197</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://repository.tamu.edu/handle/1969.1/3845"> <span id="translatedtitle">Multi-DOF <span class="hlt">precision</span> <span class="hlt">positioning</span> methodology using two-axis Hall-effect sensors</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">as additional estimates of velocity and angular velocity, which we can use to design a multivariable controller. The sensor and its algorithm is implemented to a magnetic levitation (maglev) stage <span class="hlt">positioned</span> atop a Halbach magnet matrix. Preliminary experimental...</p> <div class="credits"> <p class="dwt_author">Kawato, Yusuke</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-08-16</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">198</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/46353646"> <span id="translatedtitle">Modelling of differential single difference receiver clock bias for <span class="hlt">precise</span> <span class="hlt">positioning</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A receiver hardware delay should be seriously considered for time-transfer and determination of ionospheric delay corrections for wide area differential GPS <span class="hlt">positioning</span>. A receiver hardware delay does not generally effect the common geo-<span class="hlt">position</span> application, as suitable differences of observations are used, or equivalently, clock error parameters are introduced, epoch-wise, that also absorb the delays. This paper investigates the behavior of</p> <div class="credits"> <p class="dwt_author">Xianglin Liu; Christian Tiberius; Kees de Jong</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">199</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19920007593&hterms=sb&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsb"> <span id="translatedtitle">Apparatus for <span class="hlt">precision</span> focussing and <span class="hlt">positioning</span> of a beam waist on a target</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The invention relates to optical focussing apparatus and, more particularly, to optical apparatus for focussing a highly collimated Gaussian beam which provides independent and fine control over the focus waist diameter, the focus <span class="hlt">position</span> both along the beam axis and transverse to the beam, and the focus angle. A beam focussing and <span class="hlt">positioning</span> apparatus provides focussing and <span class="hlt">positioning</span> for the waist of a waisted beam at a desired location on a target such as an optical fiber. The apparatus includes a first lens, having a focal plane f sub 1, disposed in the path of an incoming beam and a second lens, having a focal plane f sub 2 and being spaced downstream from the first lens by a distance at least equal to f sub 1 + 10 f sub 2, which cooperates with the first lens to focus the waist of the beam on the target. A rotatable optical device, disposed upstream of the first lens, adjusts the angular orientation of the beam waist. The transverse <span class="hlt">position</span> of the first lens relative to the axis of the beam is varied to control the transverse <span class="hlt">position</span> of the beam waist relative to the target (a fiber optic as shown) while the relative axial <span class="hlt">positions</span> of the lenses are varied to control the diameter of the beam waist and to control the axial <span class="hlt">position</span> of the beam waist. Mechanical controllers C sub 1, C sub 2, C sub 3, C sub 4, and C sub 5 control the elements of the optical system. How seven adjustments can be made to correctly couple a laser beam into an optical fiber is illustrated. Prior art systems employing optical techniques to couple a laser beam into an optical fiber or other target simply do not provide the seven necessary adjustments. The closest known prior art, a Newport coupler, provides only two of the seven required adjustments.</p> <div class="credits"> <p class="dwt_author">Lynch, Dana H. (inventor); Gunter, William D. (inventor); Mcalister, Kenneth W. (inventor)</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">200</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013FrME....8..252J"> <span id="translatedtitle">Kinematic calibration of <span class="hlt">precise</span> 6-DOF Stewart platform-type <span class="hlt">positioning</span> systems for radio telescope applications</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The pose accuracy of a parallel robot is a function of the mobile platform posture. Thus, there is no a single value of the robot's accuracy. In this paper, two novel methods for estimating the accuracy of parallel robots are presented. In the first method, the pose accuracy estimation is calculated by considering the propagation of each error, i.e., error variations are considered as a function of the actuator's stroke. In the second method, it is considered that each actuator has a constant error at any stroke. Both methods can predict pose accuracy of <span class="hlt">precise</span> robots at design stages, and/or can reduce calibration time of existing robots. An example of a six degree-of-freedom parallel manipulator is included to show the application of the proposed methods.</p> <div class="credits"> <p class="dwt_author">Jáuregui, Juan Carlos; Hernández, Eusebio E.; Ceccarelli, Marco; López-Cajún, Carlos; García, Alejandro</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-09-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_9");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous 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showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_12");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">201</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009JGeod..83...91M"> <span id="translatedtitle">Deploying a Locata network to enable <span class="hlt">precise</span> <span class="hlt">positioning</span> in urban canyons</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Locata is a new <span class="hlt">positioning</span> technology developed by the Locata Corporation. At the beginning of 2007, the Institute of Engineering Surveying and Space Geodesy (IESSG) bought and received a network of Locata transceivers with two rovers. The purpose is to solve the challenges identified when surveying in dense multipath areas (i.e. urban canyons). In this paper, the technology is tested in an urban canyon scenario on the University park at the University of Nottingham. By comparing Locata <span class="hlt">position</span> solutions with the true <span class="hlt">positions</span> calculated with a total station and a carrier-phase GPS, the results show that centimetre-level accuracy is achievable in difficult environments in the presence of Wi-Fi signals. The rover’s estimated coordinates may diverge in some cases. Finally, a comparison study shows that Real Time Kinematic GPS and Locata technologies have similar accuracy when both are available.</p> <div class="credits"> <p class="dwt_author">Montillet, J.-P.; Roberts, G. W.; Hancock, C.; Meng, X.; Ogundipe, O.; Barnes, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">202</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54354712"> <span id="translatedtitle">Application of extended Lagrange series to the <span class="hlt">precise</span> determination of Global <span class="hlt">Positioning</span> Satellite orbits</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A new semi-analytical method is presented for solving the calculation of the perturbed orbits of Global <span class="hlt">Positioning</span> System (GPS) satellites. Preliminary notions concerning coordinates, Keplerian orbits, and the perturbed orbit are established. The basic principles of the analytical and numerical method are introduced along with the models of the principal perturbations affecting the GPS satellites. Different methods of orbit calculation</p> <div class="credits"> <p class="dwt_author">Caroline Huot</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">203</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.nbmg.unr.edu/staff/pdfs/Vigue_92GL01575.pdf"> <span id="translatedtitle"><span class="hlt">Precise</span> determination of Earth's center of mass using measurements from the global <span class="hlt">positioning</span> system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Global <span class="hlt">Positioning</span> System (GPS) data from a worldwide geodetic experiment were collected during a 3 week period early in 1991. We estimated geocentric station coordinates using the GPS data, thus defining a dynamically determined reference frame origin which should coincide with the Earth center of mass, or geocenter. The 3-week GPS av- erage geocenter estimates agree to 7-13 cm with</p> <div class="credits"> <p class="dwt_author">Yvonne Vigue; Stephen M. Lichten; Geoffrey Blewitt; Michael B. Heflin; Rajendra P. Malla</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">204</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50448473"> <span id="translatedtitle">High-<span class="hlt">Precision</span> Resonant Cavity Beam <span class="hlt">Position</span>, Emittance and Third-Moment Monitors</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Linear colliders and FEL facilities need fast, nondestructive beam <span class="hlt">position</span> and profile monitors to facilitate machine tune-up, and for use with feedback control. FAR-TECH, Inc., in collaboration with SLAC, is developing a resonant cavity diagnostic to simultaneously measure the dipole, quadrupole and sextupole moments of the beam distribution. Measurements of dipole and quadrupole moments at multiple locations yield information about</p> <div class="credits"> <p class="dwt_author">N. Barov; J. S. Kim; A. W. Weidemann; R. H. Miller; C. D. Nantista</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">205</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.tu-ilmenau.de/fileadmin/public/regelungstechnik/Mitarbeiter/Prof_Johann_Reger/reger_IWK_2_2010.pdf"> <span id="translatedtitle">MODELLING AND IDENTIFICATION OF A HIGH-<span class="hlt">PRECISION</span> PLANAR <span class="hlt">POSITIONING</span> SYSTEM</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">-- planar <span class="hlt">positioning</span> system, air bearing, electro magnetic propulsion, physical modelling 1. INTRODUCTION of the slider is 200x200mm2 and the maximal yaw angle is ±0.25 . A number of perma- nent magnets are mounted at the bottom of the slider. Those magnets are hovering above rigidly fixed current-carrying con- ductors</p> <div class="credits"> <p class="dwt_author">Knobloch,Jürgen</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">206</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10573"> <span id="translatedtitle">Vibratory response of a <span class="hlt">precision</span> double-multi-layer monochromator <span class="hlt">positioning</span> system using a generic modeling program with experimental verification.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A generic vibratory response-modeling program has been developed as a tool for designing high-<span class="hlt">precision</span> optical <span class="hlt">positioning</span> systems. The systems are modeled as rigid-body structures connected by linear non-rigid elements such as complex actuators and bearings. The full dynamic properties of each non-rigid element are determined experimentally or theoretically, then integrated into the program as inertial and stiffness matrices. Thus, it is possible to have a suite of standardize structural elements for modeling many different <span class="hlt">positioning</span> systems that use standardized components. This paper will present the application of this program to a double-multi-layer monochromator <span class="hlt">positioning</span> system that utilizes standardized components. Calculated results are compared to experimental modal analysis results.</p> <div class="credits"> <p class="dwt_author">Barraza, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-07-29</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">207</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014JGeod..88..659P"> <span id="translatedtitle"><span class="hlt">Precise</span> station <span class="hlt">positions</span> from VLBI observations to satellites: a simulation study</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Very long baseline interferometry (VLBI) tracking of satellites is a topic of increasing interest for the establishment of space ties. This shall strengthen the connection of the various space geodetic techniques that contribute to the International Terrestrial Reference Frame. The concept of observing near-Earth satellites demands research on possible observing strategies. In this paper, we introduce this concept and discuss its possible benefits for improving future realizations of the International Terrestrial Reference System. Using simulated observations, we develop possible observing strategies that allow the determination of radio telescope <span class="hlt">positions</span> in the satellite system on Earth with accuracies of a few millimeters up to 1-2 cm for weekly station coordinates. This is shown for satellites with orbital heights between 2,000 and 6,000 km, observed by dense regional as well as by global VLBI-networks. The number of observations, as mainly determined by the satellite orbit and the observation interval, is identified as the most critical parameter that affects the expected accuracies. For observations of global <span class="hlt">positioning</span> system satellites, we propose the combination with classical VLBI to radio sources or a multi-satellite strategy. Both approaches allow station <span class="hlt">position</span> repeatabilities of a few millimeters for weekly solutions.</p> <div class="credits"> <p class="dwt_author">Plank, Lucia; Böhm, Johannes; Schuh, Harald</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">208</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19920068544&hterms=global+positioning+system&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2522global%2Bpositioning%2Bsystem%2522"> <span id="translatedtitle"><span class="hlt">Precise</span> determination of earth's center of mass using measurements from the Global <span class="hlt">Positioning</span> System</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Global <span class="hlt">Positioning</span> System (GPS) data from a worldwide geodetic experiment were collected during a 3-week period early in 1991. Geocentric station coordinates were estimated using the GPS data, thus defining a dynamically determined reference frame origin which should coincide with the earth center of mass, or geocenter. The 3-week GPS average geocenter estimates agree to 7-13 cm with geocenter estimates determined from satellite laser ranging, a well-established technique. The RMS of daily GPS geocenter estimates were 4 cm for x and y, and 30 cm for z.</p> <div class="credits"> <p class="dwt_author">Vigue, Yvonne; Lichten, Stephen M.; Blewitt, Geoffrey; Heflin, Michael B.; Malla, Rajendra P.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">209</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014SPIE.9147E..35R"> <span id="translatedtitle"><span class="hlt">Precise</span> angular <span class="hlt">positioning</span> at 6K: the FIFI-LS grating assembly</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Field Imaging Far Infrared Line Spectrometer (FIFI-LS) obtains spectral data within two wavelength ranges. The observed wavelengths are set by rotating the two diffraction gratings to specific angles. This paper describes on the grating assemblies, designed to rotate and stabilize the gratings. First the assembly itself and its special environment inside FIFI-LS is explained. Then a method is layed out how to monitor the performance of the drive and how to detect upcoming failures before they happen. The last chapter is dedicated to first inflight measurements of the <span class="hlt">position</span> stability of the grating.</p> <div class="credits"> <p class="dwt_author">Rebell, Felix; Raab, Walfried; Colditz, Sebastian; Beckmann, Simon; Bryant, Aaron; Fischer, Christian; Fumi, Fabio; Geis, Norbert; Hönle, Rainer; Klein, Randolf; Krabbe, Alfred; Looney, Leslie; Poglitsch, Albrecht; Ragan, Sarah; Savage, Maureen</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">210</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010JAMDS...4..187Y"> <span id="translatedtitle"><span class="hlt">Precise</span> <span class="hlt">Positioning</span> Method for Logistics Tracking Systems Using Personal Handy-Phone System Based on Mahalanobis Distance</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Focusing on the Personal Handy-phone System (PHS) <span class="hlt">positioning</span> service used in physical distribution logistics, a <span class="hlt">positioning</span> error offset method for improving <span class="hlt">positioning</span> accuracy is invented. A disadvantage of PHS <span class="hlt">positioning</span> is that measurement errors caused by the fluctuation of radio waves due to buildings around the terminal are large, ranging from several tens to several hundreds of meters. In this study, an error offset method is developed, which learns patterns of <span class="hlt">positioning</span> results (latitude and longitude) containing errors and the highest signal strength at major logistic <span class="hlt">points</span> in advance, and matches them with new data measured in actual distribution processes according to the Mahalanobis distance. Then the matching resolution is improved to 1/40 that of the conventional error offset method.</p> <div class="credits"> <p class="dwt_author">Yokoi, Naoaki; Kawahara, Yasuhiro; Hosaka, Hiroshi; Sakata, Kenji</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">211</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19730053994&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">pointing</span> thrustor.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A satellite experiment to test the predicted relativistic precession of a gyroscope moving through a gravitational field has been under development at Stanford University for a number of years. The instruments will be located in a liquid helium bath to insure dimensional stability and to permit using superconducting types of circuitry for readout of the gyro orientation. Heat leaks in the system cause the helium to boil and the resultant helium gas is used for attitude control. The principal subject of the paper is the design and experimental evaluation of an electromagnetically actuated differential thrustor which was built and tested at Stanford University. The results are unique because most propulsion systems operate on-off in order to utilize propellant efficiently. In this case, the gas must flow continually to provide cooling, and the requirements are primarily for low power, small volume, and high reliability.</p> <div class="credits"> <p class="dwt_author">Bull, J. S.; Debra, D. B.</p> <p class="dwt_publisher"></p> <p class="publishDate">1973-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">212</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/1204.1876v1"> <span id="translatedtitle">Zero-<span class="hlt">point</span> energies, the uncertainty principle and <span class="hlt">positivity</span> of the quantum Brownian density operator</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">High temperature and white noise approximations are frequently invoked when deriving the quantum Brownian equation for an oscillator. Even if this white noise approximation is avoided, it is shown that if the zero <span class="hlt">point</span> energies of the environment are neglected, as they often are, the resultant equation will violate not only the basic tenet of quantum mechanics that requires the density operator to be <span class="hlt">positive</span>, but also the uncertainty principle. When the zero-<span class="hlt">point</span> energies are included, asymptotic results describing the evolution of the oscillator are obtained that preserve <span class="hlt">positivity</span> and, therefore, the uncertainty principle.</p> <div class="credits"> <p class="dwt_author">Allan Tameshtit</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-04-09</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">213</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014SPIE.9076E..0FH"> <span id="translatedtitle">Line-of-sight kinematics and corrections for fast-steering mirrors used in <span class="hlt">precision</span> <span class="hlt">pointing</span> and tracking systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Fast steering mirrors, or FSMs, have been used for several decades to enhance or augment the performance of electrooptical imaging and beam-steering systems in applications such as astronomy, laser communications and military targeting and surveillance systems. FSMs are high-<span class="hlt">precision</span>, high-bandwidth electro-mechanical mechanisms used to deflect a mirror over a small angular displacement relative to the base it is mounted on which is typically a stabilized gimbal or other primary <span class="hlt">pointing</span> device. Although the equations describing the line-of-sight kinematics derive entirely from the simple plane-mirror law of reflection, they are non-linear and axis-coupled and these effects increase as the FSM angular displacement increases. These inherent non-linearities and axis-coupling effects can contribute to <span class="hlt">pointing</span> errors in certain modes of operation. The relevant kinematic equations presented in this paper can be used to assess the magnitude of the errors for a given application and make corrections as necessary.</p> <div class="credits"> <p class="dwt_author">Hilkert, J. M.; Kanga, Gavin; Kinnear, K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">214</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1993STIN...9430237H"> <span id="translatedtitle">Application of extended Lagrange series to the <span class="hlt">precise</span> determination of Global <span class="hlt">Positioning</span> Satellite orbits</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A new semi-analytical method is presented for solving the calculation of the perturbed orbits of Global <span class="hlt">Positioning</span> System (GPS) satellites. Preliminary notions concerning coordinates, Keplerian orbits, and the perturbed orbit are established. The basic principles of the analytical and numerical method are introduced along with the models of the principal perturbations affecting the GPS satellites. Different methods of orbit calculation are reviewed to demonstrate the main advantages and drawbacks of each. A comparison proves that the method of extended Lagrange series has many advantages. Contrary to Cowell's method, the extended Lagrange series method does not require any starting algorithm. The proposed method is distinguished from other techniques of integration by its simple formulation and for its facility in analyzing one or many perturbations. Results obtained using the MicroCosm program are presented which indicate that calculation of the orbit by the extended Lagrange series method is accurate to within 4 cm and 70 cm for short arcs of 6 and 10 hours respectively.</p> <div class="credits"> <p class="dwt_author">Huot, Caroline</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">215</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..1612829M"> <span id="translatedtitle">A new sensor system for accurate and <span class="hlt">precise</span> determination of sediment dynamics and <span class="hlt">position</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Sediment transport processes control many significant geomorphological changes. Consequently, sediment transport dynamics are studied across a wide range of scales leading to application of a variety of conceptually different mathematical descriptions (models) and data acquisition techniques (sensing). For river sediment transport processes both Eulerian and Lagrangian formulations are used. Data are gathered using a very wide range of sensing techniques that are not always compatible with the conceptual formulation applied. We are concerned with small to medium sediment grain-scale motion in gravel-bed rivers, and other coarse-grained environments, and: a) are developing a customised environmental sensor capable of providing coherent data that reliably record the motion; and, b) provide a mathematical framework in which these data can be analysed and interpreted, this being compatible with current stochastic approaches to sediment transport theory. Here we present results from three different aspects of the above developmental process. Firstly, we present a requirement analysis for the sensor based on the state of the art of the existing technologies. We focus on the factors that enhance data coherence and representativeness, extending the common practice for optimization which is based exclusively on electronics/computing related criteria. This analysis leads to formalization of a method that permits accurate control on the physical properties of the sensor using contemporary rapid prototyping techniques [Maniatis et al. 2013]. Secondly the first results are presented from a series of entrainment experiments in a 5 x 0.8 m flume in which a prototype sensor was deployed to monitor entrainment dynamics under increasing flow conditions (0.037 m3.s-1). The sensor was enclosed in an idealized spherical case (111 mm diameter) and placed on a constructed bed of hemispheres of the same diameter. We measured 3-axial inertial acceleration (as a measure of flow stress), with sampling frequency 4 to 10Hz, for two different initial <span class="hlt">positions</span> over a range of slopes (from 0.026 to 0.57). The results reveal forces during the pre-entrainment phase and show the effect of slope on the temporal characteristics of the process. Finally we present results from the simulations using a mathematical framework developed to integrate the inertial-dynamics data (corresponding to the above experimental procedure and sensing conceptualization) [Abeywardana et al. 2012] with the mathematical techniques used in contemporary localization applications [Zanella et al. 2012]. We specifically assess different signal filtering techniques in terms of: a) how informative they are regarding the complexity of sediment movement; and, b) how possible it is to reduce rapidly accumulating errors that occur during sensing and increase <span class="hlt">positional</span> accuracy. References Maniatis, G.; Hoey, T.; Sventek, J. Sensor Enclosures: Example Application and Implications for Data Coherence. J. Sens. Actuator Netw. 2013, 2, 761-779. Abeywardana, D. K., A. P. Hu, and N. Kularatna. "IPT charged wireless sensor module for river sedimentation detection." Sensors Applications Symposium (SAS), 2012 IEEE. IEEE, 2012. Zannella, Fillipo, and Angelo Cenedese. "Multi-agent tracking in wireless sensor networks: implementation." WSEAS Int. Conf. on Information Technology and Computer Networks (ITCN). 2012.</p> <div class="credits"> <p class="dwt_author">Maniatis, Georgios; Hoey, Trevor; Sventek, Joseph; Hodge, Rebecca</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">216</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dspace.mit.edu/handle/1721.1/76577"> <span id="translatedtitle"><span class="hlt">Point</span> of impact : delivering mission essential supplies to the warfighter through the Joint <span class="hlt">Precision</span> Airdrop System (JPADS)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">The Joint <span class="hlt">Precision</span> Airdrop System (JPADS) exists to execute logistical resupply operations using fixed and rotary wing air in a safe, effective and <span class="hlt">precise</span> manner in order to deliver supplies and equipment to intended ...</p> <div class="credits"> <p class="dwt_author">Eaton, Joshua A. N. (Joshua Andrew Norman)</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">217</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.cosmic.ucar.edu/related_papers/Ware352.pdf"> <span id="translatedtitle"><span class="hlt">Pointed</span> water vapor radiometer corrections for accurate Global <span class="hlt">Positioning</span> System surveying</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Delay of the Global <span class="hlt">Positioning</span> System (GPS) signal due to atmospheric water vapor is a major source of error in GPS surveying. Improved vertical accuracy is important for sea level and polar isostasy measurements, geodesy, normal fault motion, subsidence, earthquake studies, air and ground-based gravimetry, ice dynamics, and volcanology. We conducted a GPS survey using water vapor radiometers (WVRs) <span class="hlt">pointed</span></p> <div class="credits"> <p class="dwt_author">Randolph Ware; Christian Rocken; Fredrick Solheim; Teresa Van Hove; Chris Alber; James Johnson</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">218</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2890022"> <span id="translatedtitle">Semi-robotic 6 degree of freedom <span class="hlt">positioning</span> for intracranial high <span class="hlt">precision</span> radiotherapy; first phantom and clinical results</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Background To introduce a novel method of patient <span class="hlt">positioning</span> for high <span class="hlt">precision</span> intracranial radiotherapy. Methods An infrared(IR)-array, reproducibly attached to the patient via a vacuum-mouthpiece(vMP) and connected to the table via a 6 degree-of-freedom(DoF) mechanical arm serves as <span class="hlt">positioning</span> and fixation system. After IR-based manual prepositioning to rough treatment <span class="hlt">position</span> and fixation of the mechanical arm, a cone-beam CT(CBCT) is performed. A robotic 6 DoF treatment couch (HexaPOD™) then automatically corrects all remaining translations and rotations. This absolute <span class="hlt">position</span> of infrared markers at the first fraction acts as reference for the following fractions where patients are manually prepositioned to within ± 2 mm and ± 2° of this IR reference <span class="hlt">position</span> prior to final HexaPOD-based correction; consequently CBCT imaging is only required once at the first treatment fraction. The preclinical feasibility and attainable repositioning accuracy of this method was evaluated on a phantom and human volunteers as was the clinical efficacy on 7 pilot study patients. Results Phantom and volunteer manual IR-based prepositioning to within ± 2 mm and ± 2° in 6DoF was possible within a mean(± SD) of 90 ± 31 and 56 ± 22 seconds respectively. Mean phantom translational and rotational <span class="hlt">precision</span> after 6 DoF corrections by the HexaPOD was 0.2 ± 0.2 mm and 0.7 ± 0.8° respectively. For the actual patient collective, the mean 3D vector for inter-treatment repositioning accuracy (n = 102) was 1.6 ± 0.8 mm while intra-fraction movement (n = 110) was 0.6 ± 0.4 mm. Conclusions This novel semi-automatic 6DoF IR-based system has been shown to compare favourably with existing non-invasive intracranial repeat fixation systems with respect to handling, reproducibility and, more importantly, intra-fraction rigidity. Some advantages are full cranial <span class="hlt">positioning</span> flexibility for single and fractionated IGRT treatments and possibly increased patient comfort. PMID:20504338</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">219</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.416.3655&rank=24"> <span id="translatedtitle">Proximal <span class="hlt">Point</span> Algorithm with Schur Decomposition on the Cone of Symmetric Semidefinite <span class="hlt">Positive</span> Matrices ?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">In this work, we propose a proximal algorithm for unconstrained optimization on the cone of symmetric semidefinite <span class="hlt">positive</span> matrices. It appears to be the first in the proximal class on the set of methods that convert a Symmetric Definite <span class="hlt">Positive</span> Optimization in Nonlinear Optimization. It replaces the main iteration of the conceptual proximal <span class="hlt">point</span> algorithm by a sequence of nonlinear programming problems on the cone of diagonal definite <span class="hlt">positive</span> matrices that has the structure of the <span class="hlt">positive</span> orthant of the Euclidian vector space. We are motivated by results of the classical proximal algorithm extended to Riemannian manifolds with non <span class="hlt">positive</span> sectional curvature. An important example of such manifold is the space of symmetric definite <span class="hlt">positive</span> matrices, where the metrics is given by the Hessian of the standard barrier function ?ln det(X). Then, observing the obvious fact that proximal algorithms do not depend on the geodesics, we apply those ideas to develop a proximal <span class="hlt">point</span> algorithm for convex functions in this Riemannian metric.</p> <div class="credits"> <p class="dwt_author">Ronaldo Gregório; Paulo Roberto Oliveira</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">220</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/1048645"> <span id="translatedtitle">Development of Electronics for the ATF2 Interaction <span class="hlt">Point</span> Region Beam <span class="hlt">Position</span> Monitor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Nanometer resolution beam <span class="hlt">position</span> monitors have been developed to measure and control beam <span class="hlt">position</span> stability at the interaction <span class="hlt">point</span> region of ATF2. The <span class="hlt">position</span> of the beam has to be measured to within a few nanometers at the interaction <span class="hlt">point</span>. In order to achieve this performance, electronics for the low-Q IP-BPM was developed. Every component of the electronics have been simulated and checked on the bench and using the ATF2 beam. We will explain each component and define their working range. Then, we will show the performance of the electronics measured with beam signal. ATF2 is a final focus test beam line for ILC in the framework of the ATF international collaboration. The new beam line was constructed to extend the extraction line at ATF, KEK, Japan. The first goal of ATF2 is the acheiving of a 37 nm vertical beam size at focal <span class="hlt">point</span> (IP). The second goal is to stabilize the beam at the focal <span class="hlt">point</span> at a few nanometer level for a long period in order to ensure the high luminosity. To achieve these goals a high resolution IP-BPM is essential. In addition for feedback applications a low-Q system is desirable.</p> <div class="credits"> <p class="dwt_author">Kim, Youngim; /Kyungpook Natl. U.; Heo, Ae-young; /Kyungpook Natl. U.; Kim, Eun-San; /Kyungpook Natl. U.; Boogert, Stewart; /Royal Holloway, U. of London; Honda, Yosuke; /KEK, Tsukuba; Tauchi, Toshiaki; /KEK, Tsukuba; Terunuma, Nobuhiro; /KEK, Tsukuba; May, Justin; /SLAC; McCormick, Douglas; /SLAC; Smith, Tonee; /SLAC</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-08-14</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_10");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> 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showDiv("page_13");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">221</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008IJTP...47.1471T"> <span id="translatedtitle">PT-Symmetric Solutions of Schrödinger Equation with <span class="hlt">Position</span>-Dependent Mass via <span class="hlt">Point</span> Canonical Transformation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">PT-symmetric solutions of Schrödinger equation are obtained for the Scarf and generalized harmonic oscillator potentials with the <span class="hlt">position</span>-dependent mass. A general <span class="hlt">point</span> canonical transformation is applied by using a free parameter. Three different forms of mass distributions are used. A set of the energy eigenvalues of the bound states and corresponding wave functions for target potentials are obtained as a function of the free parameter.</p> <div class="credits"> <p class="dwt_author">Tezcan, Cevdet; Sever, Ramazan</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">222</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/1057654"> <span id="translatedtitle">PT-symmetric Solutions of Schrodinger Equation with <span class="hlt">position</span>-dependent mass via <span class="hlt">Point</span> Canonical Transformation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">PT-symmetric solutions of Schrodinger equation are obtained for the Scarf and generalized harmonic oscillator potentials with the <span class="hlt">position</span>-dependent mass. A general <span class="hlt">point</span> canonical transformation is applied by using a free parameter. Three different forms of mass distributions are used. A set of the energy eigenvalues of the bound states and corresponding wave functions for target potentials are obtained as a function of the free parameter.</p> <div class="credits"> <p class="dwt_author">Tezcand, Cevdet</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">223</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/0709.2789v1"> <span id="translatedtitle">PT-symmetric Solutions of Schrodinger Equation with <span class="hlt">position</span>-dependent mass via <span class="hlt">Point</span> Canonical Transformation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">PT-symmetric solutions of Schrodinger equation are obtained for the Scarf and generalized harmonic oscillator potentials with the <span class="hlt">position</span>-dependent mass. A general <span class="hlt">point</span> canonical transformation is applied by using a free parameter. Three different forms of mass distributions are used. A set of the energy eigenvalues of the bound states and corresponding wave functions for target potentials are obtained as a function of the free parameter.</p> <div class="credits"> <p class="dwt_author">Cevdet Tezcand; Ramazan Sever</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-09-18</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">224</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014JChPh.141b4109P"> <span id="translatedtitle">Bowl breakout: Escaping the <span class="hlt">positive</span> region when searching for saddle <span class="hlt">points</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present a scheme improving the minimum-mode following method for finding first order saddle <span class="hlt">points</span> by confining the displacements of atoms to the subset of those subject to the largest force. By doing so it is ensured that the displacement remains of a local character within regions where all eigenvalues of the Hessian matrix are <span class="hlt">positive</span>. However, as soon as a region is entered where an eigenvalue turns negative all atoms are released to maintain the ability of determining concerted moves. Applying the proposed scheme reduces the required number of force calls for the determination of connected saddle <span class="hlt">points</span> by a factor two or more compared to a free search. Furthermore, a wider distribution of the relevant low barrier saddle <span class="hlt">points</span> is obtained. Finally, the dependency on the initial distortion and the applied maximal step size is reduced making minimum-mode guided searches both more robust and applicable.</p> <div class="credits"> <p class="dwt_author">Pedersen, Andreas; Luiser, Mathieu</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">225</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014PhRvB..90p5133C"> <span id="translatedtitle">Band-edge <span class="hlt">positions</span> in G W : Effects of starting <span class="hlt">point</span> and self-consistency</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We study the effect of starting <span class="hlt">point</span> and self-consistency within G W on the band-edge <span class="hlt">positions</span> of semiconductors and insulators. Compared to calculations based on a semilocal starting <span class="hlt">point</span>, the use of a hybrid-functional starting <span class="hlt">point</span> shows a larger quasiparticle correction for both band-edge states. When the self-consistent treatment is employed, the band-gap opening is found to result mostly from a shift of the valence-band edge. Within the non-self-consistent methods, we analyse the performance of empirical and nonempirical schemes in which the starting <span class="hlt">point</span> is optimally tuned. We further assess the accuracy of the band-edge <span class="hlt">positions</span> through the calculation of ionization potentials of surfaces. The ionization potentials for most systems are reasonably well described by one-shot calculations. However, in the case of TiO2, we find that the use of self-consistency is critical to obtain a good agreement with experiment.</p> <div class="credits"> <p class="dwt_author">Chen, Wei; Pasquarello, Alfredo</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">226</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21057461"> <span id="translatedtitle">Influence of the focal <span class="hlt">point</span> <span class="hlt">position</span> on the properties of a laser-produced plasma</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This paper deals with investigations of the influence of the focusing lens focal <span class="hlt">point</span> <span class="hlt">position</span> on the properties of a plasma produced by a defocused laser beam. The experiment was carried out at the Prague Asterix Laser System iodine laser [K. Jungwirth, A. Cejnarova, L. Juha, B. Kralikova, J. Krasa, E. Krousky, P. Krupickova, L. Laska, K. Masek, T. Mocek, M. Pfeifer, A. Prag, O. Renner, K. Rohlena, B. Rus, J. Skala, P. Straka, and J. Ullschmied, Phys. Plasmas 8, 2495 (2001)] by using the third harmonic of laser radiation ({lambda}=0.438 {mu}m), laser energy of 70 J, pulse duration of 250 ps (full width at half-maximum), and beam spot radii of 250 and 400 {mu}m. Cu and Ta were chosen as target materials. The experimental data were obtained by means of a three-frame interferometric system, ion collectors, and crater replica techniques. The reported results allow formulating an important hypothesis that the laser-produced plasma modifies strongly the laser intensity distribution. It is shown how such a modification depends on the relative <span class="hlt">position</span> and distance of the focal <span class="hlt">point</span> to the target surface. Of particular importance is whether the focal <span class="hlt">point</span> is located inside or in front of the target. The irradiation geometry is crucial for the possibility of generating plasma jets by laser radiation. Well-formed jet-like plasma structures can be created if an initially homogeneous laser intensity distribution is transformed in the plasma to an annular one.</p> <div class="credits"> <p class="dwt_author">Kasperczuk, A.; Pisarczyk, T.; Badziak, J.; Miklaszewski, R.; Parys, P.; Rosinski, M.; Wolowski, J.; Stenz, CH.; Ullschmied, J.; Krousky, E.; Masek, K.; Pfeifer, M.; Rohlena, K.; Skala, J.; Pisarczyk, P. [Institute of Plasma Physics and Laser Microfusion, 23 Hery St., 00-908 Warsaw (Poland); Centre Lasers Intenses et Applications, Universite Bordeaux, 33405 Talence (France); Institute of Plasma Physics AS CR, Za Slovankou 3, 182 00 Prague 8 (Czech Republic); Institute of Physics AS CR, Na Slovance 2, 182 21 Prague 8 (Czech Republic); Warsaw University of Technology, ICS, 15/19 Nowowiejska St., 00-665 Warsaw (Poland)</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-10-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">227</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/1422185"> <span id="translatedtitle">Robust and <span class="hlt">precision</span> motion control system of linear-motor direct drive for high-speed X-Y table <span class="hlt">positioning</span> mechanism</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this paper, design and implementation of an H?-based <span class="hlt">precision</span> motion control system is presented for a high-speed linear-motor direct-drive X-Y table <span class="hlt">positioning</span> mechanism in semiconductor wire-bonding applications. The system works with a cascaded robust feedback control, which has an inner loop velocity controller and an outer loop <span class="hlt">position</span> controller, and an autotuning feedforward compensator. The design aim is to</p> <div class="credits"> <p class="dwt_author">Zuo Zong Liu; Fang Lin Luo; M. Azizur Rahman</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">228</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/53887323"> <span id="translatedtitle">A time domain design technique for high <span class="hlt">precision</span> full digital <span class="hlt">pointing</span> system in balloon-borne remote infrared sensing</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The design of two motor servoloops for an azimuth stabilization of a gondola of a large telescope is described. The system uses two dc torque motors, one for any motion of the platform around the vertical axis and one placed at the interconnecting <span class="hlt">point</span> balloon-payload for attenuating the friction bearing. Mechanical nonlinearities impose a time domain design for any settling</p> <div class="credits"> <p class="dwt_author">A. Boscaleri; V. Venturi; A. Tronconi; R. Colzi</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">229</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/29289529"> <span id="translatedtitle">Effects of recording speed on <span class="hlt">precision</span> of time-based polycardiographic measurements. Optimal paper speeds for measuring <span class="hlt">points</span> and intervals</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Optimal paper speeds have not been established for all time-based measurements of the cardiac cycle by appropriately designed observer performance studies. In 10 subjects (5 normals and 5 cardiac patients) carotid pulse, phonocardiogram, and electrocardiogram were recorded on magnetic tape for measurement of all fiducial <span class="hlt">points</span> for systolic time intervals, the systolic time intervals themselves, the pulse transmission time, cycle</p> <div class="credits"> <p class="dwt_author">D H Spodick; H G Ball; V M Pigott</p> <p class="dwt_publisher"></p> <p class="publishDate">1978-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">230</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26666604"> <span id="translatedtitle">Requirement of a robust method for the <span class="hlt">precise</span> determination of the contact <span class="hlt">point</span> in the depth sensing hardness test</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The fundamental quantities in the depth sensing hardness test are force and displacement. The penetration depth used for the calculation of a certain hardness parameter (for instance HU, Eq. (1)) makes it necessary to determine the contact <span class="hlt">point</span>. As shown in the paper, fitting of the force–displacement curve, F(h), by a second order polynomial and extrapolating to F=0 is not</p> <div class="credits"> <p class="dwt_author">Christian Ullner</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">231</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014MNRAS.444.3308P"> <span id="translatedtitle"><span class="hlt">Positions</span> of equilibrium <span class="hlt">points</span> for dust particles in the circular restricted three-body problem with radiation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">For a body with negligible mass moving in the gravitational field of a star with one planet in a circular orbit (the circular restricted three-body problem), five equilibrium <span class="hlt">points</span> exist and are known as the Lagrangian <span class="hlt">points</span>. The <span class="hlt">positions</span> of the Lagrangian <span class="hlt">points</span> are not valid for dust particles because in the derivation of the Lagrangian <span class="hlt">points</span> it is assumed that no other forces besides the gravitation act on the body with negligible mass. Here, we determined <span class="hlt">positions</span> of the equilibrium <span class="hlt">points</span> for the dust particles in the circular restricted three-body problem with radiation. The equilibrium <span class="hlt">points</span> are located on curves connecting the Lagrangian <span class="hlt">points</span> in the circular restricted three-body problem. The equilibrium <span class="hlt">points</span> for Jupiter are distributed in large interval of heliocentric distances due to its large mass. The equilibrium <span class="hlt">points</span> for the Earth explain a cloud of dust particles trailing the Earth observed with the Spitzer Space Telescope. The dust particles moving in the equilibrium <span class="hlt">points</span> are distributed in interplanetary space according to their properties.</p> <div class="credits"> <p class="dwt_author">Pástor, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">232</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFMED31A0700K"> <span id="translatedtitle">New Method for Determining Isotopic Values of Glutamic Acid and Phenylalanine for Estimation of <span class="hlt">Precise</span> Trophic <span class="hlt">Position</span> in Food Web Studies</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Compound Specific Isotope Analysis of Amino Acids (CSI-AA) has emerged as a highly <span class="hlt">precise</span> new method of determining trophic levels of both aquatic and terrestrial organisms. Multiple studies have now shown that ?15N values for glutamic acid (Glu) and phenylalanine (Phe) can be coupled to provide extremely <span class="hlt">precise</span> estimates of trophic <span class="hlt">position</span> in diverse food web studies. The standard gas chromatography—isotope ratio mass spectrometer (GC-IRMS) approach is presently limited to a select number of labs since necessary equipment is both expensive and not widely accessible. Furthermore, typical GC-IRMS ?15N <span class="hlt">precision</span> (±1‰) is significantly lower than usual bulk ?15N values (±0.1‰), thus presenting a considerable setback for <span class="hlt">precise</span> trophic level calculations. In this study, we develop a new dual-column method to purify Glu and Phe using high performance liquid chromatography (HPLC). Phe is purified using an analytical scale reverse phase column embedded with anionic ion-pairing reagents and collected using automated fraction collection. Glu is separated from the non-polar amino acids using the same column and further purified using a hydrophilic interaction liquid chromatography (HILIC) cation and anion-exchange column and collected via automated fraction collection. Isotopic analysis of the purified AAs is then conducted on an elemental analyzer—isotope ratio mass spectrometer (EA-IRMS). As a test of this method, we present and compare the trophic <span class="hlt">position</span> of five marine organisms—cyanobacteria, deep-sea bamboo coral, juvenile and adult white sea bass, and harbor seal, calculated using Glu and Phe ?15N values produced by both GC-IRMS and our HPLC-EA-IRMS approach. The preliminary results of this study suggest that the HPLC-EA-IRMS method is a viable alternative to GC-IRMS, which should allow accurate trophic <span class="hlt">position</span> estimates to be made by more researchers using more readily available instrumentation.</p> <div class="credits"> <p class="dwt_author">Kamath, T.; Broek, T.; McCarthy, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">233</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014PhRvC..90d4302C"> <span id="translatedtitle"><span class="hlt">Precise</span> measurements of the Bk97249 ground state half-life and the ?--decay end-<span class="hlt">point</span> energy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The half-life of the Bk249 ground state was determined by means of ?-ray spectroscopy, following for 728 days the growth of its ?-decaying daughter nuclide Cf249. Using a chemically purified source containing Bk249 and Cs137 nuclides, ?-ray singles measurements were carried out using a 25% coaxial Ge detector. The areas of the strongest 333.37- and 388.17-keV ?-ray peaks, produced in the ? decay of Cf249, and the 661.66-keV peak, produced in the ?- decay of Cs137, were determined. The measured activity of the latter was used to account for geometrical and dead-time corrections to the efficiency of the spectrometer, thus minimizing the systematic uncertainties associated with long-time, ?-ray counting measurements. Using the growth with time of the ratio of the 388.17- and 661.66-keV ?-ray peaks, a value of T1/2=327.2±0.3 d (the uncertainty quoted is one standard deviation, 1?) for the half-life of the Bk249 ground state was determined. The ?--decay end-<span class="hlt">point</span> energy of Bk249 was measured with a passivated implanted planar silicon detector to be 123.6±0.4 keV.</p> <div class="credits"> <p class="dwt_author">Chen, J.; Ahmad, I.; Greene, J. P.; Kondev, F. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">234</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21796408"> <span id="translatedtitle">Atlas of the muscle motor <span class="hlt">points</span> for the lower limb: implications for electrical stimulation procedures and electrode <span class="hlt">positioning</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The aim of the study was to investigate the uniformity of the muscle motor <span class="hlt">point</span> location for lower limb muscles in healthy subjects. Fifty-three subjects of both genders (age range: 18-50 years) were recruited. The muscle motor <span class="hlt">points</span> were identified for the following ten muscles of the lower limb (dominant side): vastus medialis, rectus femoris, and vastus lateralis of the quadriceps femoris, biceps femoris, semitendinosus, and semimembranosus of the hamstring muscles, tibialis anterior, peroneus longus, lateral and medial gastrocnemius. The muscle motor <span class="hlt">point</span> was identified by scanning the skin surface with a stimulation pen electrode and corresponded to the location of the skin area above the muscle in which an electrical pulse evoked a muscle twitch with the least injected current. For each investigated muscle, 0.15 ms square pulses were delivered through the pen electrode at low current amplitude (<10 mA) and frequency (2 Hz). 16 motor <span class="hlt">points</span> were identified in the 10 investigated muscles of almost all subjects: 3 motor <span class="hlt">points</span> for the vastus lateralis, 2 motor <span class="hlt">points</span> for rectus femoris, vastus medialis, biceps femoris, and tibialis anterior, 1 motor <span class="hlt">point</span> for the remaining muscles. An important inter-individual variability was observed for the <span class="hlt">position</span> of the following 4 out of 16 motor <span class="hlt">points</span>: vastus lateralis (proximal), biceps femoris (short head), semimembranosus, and medial gastrocnemius. Possible implications for electrical stimulation procedures and electrode <span class="hlt">positioning</span> different from those commonly applied for thigh and leg muscles are discussed. PMID:21796408</p> <div class="credits"> <p class="dwt_author">Botter, Alberto; Oprandi, Gianmosè; Lanfranco, Fabio; Allasia, Stefano; Maffiuletti, Nicola A; Minetto, Marco Alessandro</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">235</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=Finger&pg=2&id=EJ819921"> <span id="translatedtitle">The Speech Focus <span class="hlt">Position</span> Effect on Jaw-Finger Coordination in a <span class="hlt">Pointing</span> Task</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Purpose: This article investigates jaw-finger coordination in a task involving <span class="hlt">pointing</span> to a target while naming it with a 'CVCV (e.g., /'papa/) versus CV'CV (e.g., /pa'pa/) word. According to the authors' working hypothesis, the <span class="hlt">pointing</span> apex (gesture extremum) would be synchronized with the apex of the jaw-opening gesture corresponding to the…</p> <div class="credits"> <p class="dwt_author">Rochet-Capellan, Amelie; Laboissiere, Rafael; Galvan, Arturo; Schwartz, Jean-Luc</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">236</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/940998"> <span id="translatedtitle">Exact Solutions of the Schr\\"{o}dinger Equation with <span class="hlt">position</span>-dependent effective mass via general <span class="hlt">point</span> canonical transformation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Exact solutions of the Schrodinger equation are obtained for the Rosen-Morse and Scarf potentials with the <span class="hlt">position</span>-dependent effective mass by appliying a general <span class="hlt">point</span> canonical transformation. The general form of the <span class="hlt">point</span> canonical transformation is introduced by using a free parameter. Two different forms of mass distributions are used. A set of the energy eigenvalues of the bound states and corresponding wave functions for target potentials are obtained as a function of the free parameter.</p> <div class="credits"> <p class="dwt_author">Tezcan, C; Tezcan, Cevdet; Sever, Ramazan</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">237</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/quant-ph/0604041v1"> <span id="translatedtitle">Exact Solutions of the Schrödinger Equation with <span class="hlt">position</span>-dependent effective mass via general <span class="hlt">point</span> canonical transformation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Exact solutions of the Schrodinger equation are obtained for the Rosen-Morse and Scarf potentials with the <span class="hlt">position</span>-dependent effective mass by appliying a general <span class="hlt">point</span> canonical transformation. The general form of the <span class="hlt">point</span> canonical transformation is introduced by using a free parameter. Two different forms of mass distributions are used. A set of the energy eigenvalues of the bound states and corresponding wave functions for target potentials are obtained as a function of the free parameter.</p> <div class="credits"> <p class="dwt_author">Cevdet Tezcan; Ramazan Sever</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-04-06</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">238</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50114478"> <span id="translatedtitle">Adaptive high <span class="hlt">precision</span> <span class="hlt">position</span> control for a flexible joint with friction and parameter uncertainties using neural networks</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Dynamic <span class="hlt">position</span>-control of a flexible joint is proposed by applying adaptive control and artificial neural networks (ANNs). A flexible joint is modeled, including Coulomb and static frictions and the model is represented as an ANN. The control strategy is based on a dual loop strategy. An outer load state feedback is used to compute desired load torque and motor state.</p> <div class="credits"> <p class="dwt_author">E. Y. O. Sidi; P. Sicard; D. Massicotte; S. Lesueur</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">239</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cct.gfy.ku.dk/publ_cct/cct331.pdf"> <span id="translatedtitle">The <span class="hlt">precise</span> computation of geoid undulation differences with comparison to results obtained from the global <span class="hlt">positioning</span> system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Ellipsoidal height differences have been determined for 13 station pairs in the central Ohio region using measurements made with the Global <span class="hlt">Positioning</span> System. This information was used to compute geoid undulation differences based on known orthometric heights. These differences were compared to gravimetrically-computed undulations (using a Stokes integration procedure, and least squares collocation having an internal r.m.s. agreement of plus</p> <div class="credits"> <p class="dwt_author">Theo Engelis; R. H. Rapp; C. C. Tscherning</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">240</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.udayton.edu/kissock/http/Publications/CommonExcessAirTrndsInBoilers_ACEEE_2007.pdf"> <span id="translatedtitle">Common Excess Air Trends in Industrial Boilers with Single-<span class="hlt">Point</span> <span class="hlt">Positioning</span> Control and Strategies to Optimize Efficiency</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Common Excess Air Trends in Industrial Boilers with Single-<span class="hlt">Point</span> <span class="hlt">Positioning</span> Control and Strategies mechanically linking the fuel valve and combustion air damper. To match combustion air flow with fuel input air control in boilers and methods to quantify both boiler efficiency as a function of excess air</p> <div class="credits"> <p class="dwt_author">Kissock, Kelly</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_11");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return 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showDiv("page_14");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">241</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850022722&hterms=satelli+clock&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsatelli%2Bclock"> <span id="translatedtitle">A study of the application of differential techniques to the global <span class="hlt">positioning</span> system for a helicopter <span class="hlt">precision</span> approach</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The results of a simulation study to define the functional characteristics of a airborne and ground reference GPS receiver for use in a Differential GPS system are doumented. The operations of a variety of receiver types (sequential-single channel, continuous multi-channel, etc.) are evaluated for a typical civil helicopter mission scenario. The math model of each receiver type incorporated representative system errors including intentional degradation. The results include the discussion of the receiver relative performance, the spatial correlative properties of individual range error sources, and the navigation algorithm used to smooth the <span class="hlt">position</span> data.</p> <div class="credits"> <p class="dwt_author">Mccall, D. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">242</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://users.rsise.anu.edu.au/~hartley/Papers/focal-lengths-2000/focal.pdf"> <span id="translatedtitle">Sensitivity of calibration to principal <span class="hlt">point</span> <span class="hlt">position</span> R. I. Hartley R. Kaucic</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">. G.E. ­ CRD, RSISE, A.N.U., Schenectady, ACT, 0200 New York, 12309 AUSTRALIA U.S.A. Richard. It is the purpose of this paper to refute that belief. Indeed, it is demonstrated that the determination. Given knowledge of the principal <span class="hlt">point</span>, the focal length may be determined by an easy geometric</p> <div class="credits"> <p class="dwt_author">Hartley, Richard</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">243</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19910059796&hterms=global+positioning+system&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2522global%2Bpositioning%2Bsystem%2522"> <span id="translatedtitle">A scheme for reducing the effect of selective availability on <span class="hlt">precise</span> geodetic measurements from the Global <span class="hlt">Positioning</span> System</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">From March to August 1990, the signals transmitted by the Block II satellites of the GPS were dithered under a policy of 'Selective Availability' (SA). The dithering appears as an about 10 to the -10th deviation of the satellite oscillator frequency, which, when accumulated over several minutes, can produce an error of about 100 cycles in the model for carrier beat phase. Differencing between simultaneously sampling receivers minimizes the error. If, however, the receivers do not sample simultaneously, it is necessary to model the frequency deviation. Such a model is here applied to data collected in March 1990 by TI4100 and Minimac receivers sampling at times separated by 0.92 s. Applying the algorithm significantly improves the rms scatter of the estimated relative <span class="hlt">position</span> vectors. The rms scatter from a data set including dithered satellites is similar for both simultaneously and nonsimultaneously sampling receivers, a result which indicates that SA can be adequately modeled.</p> <div class="credits"> <p class="dwt_author">Feigl, Kurt L.; King, Robert W.; Herring, Thomas A.; Rothacher, Markus</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">244</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://hal.archives-ouvertes.fr/docs/00/11/12/50/PDF/ijnme98_bg_ms.pdf"> <span id="translatedtitle">Tangential derivative of singular boundary integrals with respect to the <span class="hlt">position</span> of collocation <span class="hlt">points</span>1</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Tangential derivative of singular boundary integrals with respect to the <span class="hlt">position</span> of collocation potential and elastic problems are considered. A proper definition of the derivative of a strongly singular residual function is found to be equal to the derivative of the strongly singular BIE residual when</p> <div class="credits"> <p class="dwt_author">Paris-Sud XI, Université de</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">245</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/16010145"> <span id="translatedtitle">Matching <span class="hlt">point</span>-of care devices to clinicians for <span class="hlt">positive</span> outcomes.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Home care clinicians' use of <span class="hlt">point</span>-of-care (POC) technology has increased 63% in the past 5 years. Although there are more POC system choices, matching the right device to each clinician's role is a challenge. This article clarifies the uses of laptop or notebook computer, personal digital assistants (PDAs), telephony, or automated telehealth, suggesting ways these technologies can result in clinical efficiencies, care coordination, and regulatory compliance. PMID:16010145</p> <div class="credits"> <p class="dwt_author">Utterback, Karen; Waldo, Billie H</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">246</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2001RScI...72.3086A"> <span id="translatedtitle"><span class="hlt">Precision</span> alignment of the LIGO 4 km arms using the dual-frequency differential global <span class="hlt">positioning</span> system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The alignment of the Laser Interferometer Gravitational-Wave Observatory (LIGO) using the global <span class="hlt">positioning</span> system (GPS) is described. The LIGO project is designed to detect gravitational waves from astrophysical sources by laser interferometry. There are two sites separated by 3002 km that will be operated in coincidence. At each site, laser beams propagate in two orthogonal 4 km long evacuated beam lines 1.2 m in diameter. The subject of this article is the alignment of the 16 km of beam tubes using dual-frequency differential GPS. A maximum deviation from straightness in inertial space of 5 mm root mean square and an orthogonality between arm pairs of better than 5 ?rad is reported. Analysis of the as-built alignment data allows determination of the geodetic coordinates for the vertices and the arm orientations at both sites. From this information, the baseline distance between the vertices of the Hanford, Washington and Livingston, Louisiana sites was determined to be 3001.8 km.</p> <div class="credits"> <p class="dwt_author">Althouse, W. E.; Hand, S. D.; Jones, L. K.; Lazzarini, A.; Weiss, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">247</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014PhRvL.113k6802R"> <span id="translatedtitle">Tuning the Dirac <span class="hlt">Point</span> <span class="hlt">Position</span> in Bi2Se3(0001) via Surface Carbon Doping</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Angular resolved photoemission spectroscopy in combination with ab initio calculations show that trace amounts of carbon doping of the Bi2Se3 surface allows the controlled shift of the Dirac <span class="hlt">point</span> within the bulk band gap. In contrast to expectation, no Rashba-split two-dimensional electron gas states appear. This unique electronic modification is related to surface structural modification characterized by an expansion of the top Se-Bi spacing of ?11% as evidenced by surface x-ray diffraction. Our results provide new ways to tune the surface band structure of topological insulators.</p> <div class="credits"> <p class="dwt_author">Roy, Sumalay; Meyerheim, H. L.; Ernst, A.; Mohseni, K.; Tusche, C.; Vergniory, M. G.; Menshchikova, T. V.; Otrokov, M. M.; Ryabishchenkova, A. G.; Aliev, Z. S.; Babanly, M. B.; Kokh, K. A.; Tereshchenko, O. E.; Chulkov, E. V.; Schneider, J.; Kirschner, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">248</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/25259997"> <span id="translatedtitle">Tuning the Dirac <span class="hlt">point</span> <span class="hlt">position</span> in Bi(2)Se(3)(0001) via surface carbon doping.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Angular resolved photoemission spectroscopy in combination with ab initio calculations show that trace amounts of carbon doping of the Bi_{2}Se_{3} surface allows the controlled shift of the Dirac <span class="hlt">point</span> within the bulk band gap. In contrast to expectation, no Rashba-split two-dimensional electron gas states appear. This unique electronic modification is related to surface structural modification characterized by an expansion of the top Se-Bi spacing of ?11% as evidenced by surface x-ray diffraction. Our results provide new ways to tune the surface band structure of topological insulators. PMID:25259997</p> <div class="credits"> <p class="dwt_author">Roy, Sumalay; Meyerheim, H L; Ernst, A; Mohseni, K; Tusche, C; Vergniory, M G; Menshchikova, T V; Otrokov, M M; Ryabishchenkova, A G; Aliev, Z S; Babanly, M B; Kokh, K A; Tereshchenko, O E; Chulkov, E V; Schneider, J; Kirschner, J</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-09-12</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">249</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014IJT....35.1169L"> <span id="translatedtitle">A Method to Improve the Temperature Distribution of Holder Around the Fixed-<span class="hlt">Point</span> Cell <span class="hlt">Position</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The temperature profile along the furnaces used in heating high-temperature fixed <span class="hlt">points</span> has a crucial impact on the quality and duration of melting plateaux, accordingly the accuracy of thermodynamic temperature determination of such fixed <span class="hlt">points</span>. This paper describes a simple, yet efficient, approach for improving the temperature uniformity along a cell holder in high-temperature blackbody (HTBB) furnaces that use pyrolytic graphite rings as heating elements. The method has been applied on the KRISS' HTBB furnace. In this work, an ideal solution for arranging the heating elements inside the furnace is presented by which the temperature gradient across the cell holder can be kept as low as possible. Numerical calculations, based on a finite element method, have been carried out to find the best possible arrangement of the rings. This has been followed by measuring the temperature gradient along an empty cell holder to validate our calculations. A temperature gradient of 100 mK has been achieved at over a length of 50 mm within a cell holder of 10 cm in length. It has also been shown that for a 20 cm long holder surrounded by rings with an arbitrary resistance profile, the temperature uniformity can be improved by adding a few "hot" rings around the cell holder.</p> <div class="credits"> <p class="dwt_author">Lim, S. D.; Karmalawi, A. M.; Salim, S. G. R.; Soliman, M. A.; Kim, B. H.; Lee, D. H.; Yoo, Y. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">250</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19920069573&hterms=global+positioning+system&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2522global%2Bpositioning%2Bsystem%2522"> <span id="translatedtitle">Crustal deformation measurements in central Japan determined by a Global <span class="hlt">Positioning</span> System fixed-<span class="hlt">point</span> network</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Results are presented from temporally dense measurements of crustal deformation associated with the convergence of the Eurasian (EUR), Pacific, North American, and Philippine Sea (PHS) plates, carried out in April 1988 by a 10-station GPS fixed-<span class="hlt">point</span> network established in central Japan. Using regional orbit relaxation methods, the analysis of the first 17-month data revealed significant horizontal deformation across the Suruga trough. Namely, it was found that a site in the northern tip of PHS plate moved nearly westward with a velocity of 28 +/-5 mm per year, and a site at the southeastern tip of EUR plate moved south-southwestward with a velocity of 18 +/-5 mm per year. A significant vertical uplift with a velocity of 20 mm/yr was detected at a site inland of the Tokai district located in the Akaishi uplift zone and at a site on the Hatsushima Island in Sagami Bay.</p> <div class="credits"> <p class="dwt_author">Shimada, Seiichi; Bock, Yehuda</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">251</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19940015902&hterms=gean&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dgean"> <span id="translatedtitle">Three <span class="hlt">point</span> lead screw <span class="hlt">positioning</span> apparatus for a cavity tuning plate</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Three lead screws are provided for adjusting the <span class="hlt">position</span> of a traversing plate. Each of the three lead screws is threaded through a collar that is press fitted through the center of one of three pinion gears. A sun gear meshes with all three pinion gears and transversely moves the three lead screws upon actuation of a drive gear. The drive gear meshes with the sun gear and is driven by a handle or servomotor. When the handle or servomotor rotates the drive gear, the sun gear rotates causing the three pinion gears to rotate, thus, causing transverse movement of the three lead screws and, accordingly, transverse movement of the transversing plate. When the drive gear rotates, the traversing plate is driven in and out of a microwave cavity. Thus, the length or size of the cavity can be tuned while maintaining the traversing plate in an exact parallel relationship with an opposing plate on another end of the cavity.</p> <div class="credits"> <p class="dwt_author">Calco, Frank S. (inventor)</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">252</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19900041492&hterms=reference+frame&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dreference%2Bframe"> <span id="translatedtitle">A radio optical reference frame. I - <span class="hlt">Precise</span> radio source <span class="hlt">positions</span> determined by Mark III VLBI - Observations from 1979 to 1988 and a tie to the FK5</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Observations from 600 Mark III VLBI experiments from 1979 to 1988, resulting in 237,681 acceptable pairs of group delay and phase delay rate observations, have been used to derive <span class="hlt">positions</span> of 182 extragalactic radio sources with typical formal standard errors less than 1 mas. The sources are distributed fairly evenly above delta = -30 deg, and 70 sources have delta greater than 0 deg. Analysis with different troposphere models, as well as internal and external comparisons, indicates that a coordinate frame defined by this set of radio sources should be reliable at the 1 mas level. The right ascension zero <span class="hlt">point</span> of this reference frame has been aligned with the FK5 by using the optical <span class="hlt">positions</span> of 28 extragalactic radio sources whose <span class="hlt">positions</span> are on the FK5 system. Because of known defects in the knowledge of astronomical constants, daily nutation offsets in longitude and obliquity were determined relative to an arbitrary reference day in the set of experiments.</p> <div class="credits"> <p class="dwt_author">Ma, C.; Shaffer, D. B.; De Vegt, C.; Johnston, K. J.; Russell, J. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">253</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3951073"> <span id="translatedtitle">Development of a simple and rapid method of <span class="hlt">precisely</span> identifying the <span class="hlt">position</span> of 10B atoms in tissue: an improvement in standard alpha autoradiography</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Boron neutron capture therapy (BNCT) can be utilized to selectively kill cancer cells using a boron compound that accumulates only in cancer cells and not in normal cells. Tumor-bearing animals treated by BNCT are routinely used to evaluate long-term antitumor effects of new boron compounds. Alpha-autoradiography is one of the methods employed in the evaluation of antitumor effects. However, a standard alpha-autoradiography cannot detect the microdistribution of 10B because of the difficulty associated with the superposition of a tissue sample image and etched pits on a track detector with the etching process. In order to observe the microdistribution of 10B, some special methods of alpha-autoradiography have been developed that make use of a special track detector, or the atomic force microscope combined with X-ray and UV light irradiation. In contrast, we propose, herein, a simple and rapid method of <span class="hlt">precisely</span> identifying the <span class="hlt">position</span> of 10B using the imaging process and the shape of etched pits, such as their circularity, without the need to use special track detectors or a microscope. A brief description of this method and its verification test are presented in this article. We have established a method of detecting the microdistribution of 10B with submicron deviation between the <span class="hlt">position</span> of etched pits and the <span class="hlt">position</span> of reaction in a tissue sample, for a given circularity of etched pits. PMID:24142968</p> <div class="credits"> <p class="dwt_author">Tanaka, Hiroki; Sakurai, Yoshinori; Suzuki, Minoru; Masunaga, Shin-ichiro; Takamiya, Koichi; Maruhashi, Akira; Ono, Koji</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">254</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFM.G53B1142A"> <span id="translatedtitle">A Three Corner Hat-based analysis of station <span class="hlt">position</span> time series for the assessment of inter-technique <span class="hlt">precision</span> at ITRF co-located sites</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Assessing the uncertainty in geodetic <span class="hlt">positioning</span> is a crucial factor when combining independent space-geodetic solutions for the computation of the International Terrestrial Reference Frame (ITRF). ITRF is a combined product based on the stacking of VLBI, GPS, SLR and DORIS solutions and merging the single technique reference frames with terrestrial local tie measurements at co-located sites. In current ITRF realizations, the uncertainty evaluation of the four techniques relies on the analysis of the post-fit residuals, which are a by-product of the combination process. An alternative approach to the assessment of the inter-technique <span class="hlt">precision</span> can be offered by a Three Corner Hat (TCH) analysis of the non-linear residual time series obtained at ITRF co-location sites as a by-product of the stacking procedure. Non-linear residuals of station <span class="hlt">position</span> time series stemming from global networks of the four techniques can be modeled as a composition of periodic signals (commonly annual and semi-annual) and stochastic noise, typically characterized as a combination of flicker and white noise. Pair-wise differences of station <span class="hlt">position</span> time series of at least three co-located instruments can be formed with the aim of removing the common geophysical signal and characterizing the inter-technique <span class="hlt">precision</span>. The application of TCH relies on the hypothesis of absence of correlation between the error processes of the four techniques and assumes the stochastic noise to be Gaussian. If the hypothesis of statistical independence between the space-geodetic technique errors is amply verified, the assumption of pure white noise of the stochastic error processes appears to be more questionable. In fact, previous studies focused on geodetic <span class="hlt">positioning</span> consistently showed that flicker noise generally prevails over white noise in the analysis of global network GPS time series, whereas in VLBI, SLR and DORIS time series Gaussian noise is predominant. In this investigation, TCH is applied to the data set used for generating the ITRF2008 realization: GPS, DORIS, VLBI and SLR solutions have been rigorously re-analyzed in order to obtain consistent and comparable non-linear-residual time series of station <span class="hlt">positions</span> at ITRF co-locations. Particular emphasis is put on the analysis of the limiting factors which might affect the application of TCH to the space-geodetic <span class="hlt">positioning</span>, i.e. poorness of the current co-locations resulting in a scarce number of sites having sufficient observations, dissimilar performances varying over time of the four space-geodetic techniques, different time resolution of the four techniques and effects of the data interpolation (especially on daily VLBI data), presence of non-Gaussian and time-correlated noise for which TCH is not specifically designed.</p> <div class="credits"> <p class="dwt_author">Abbondanza, C.; Chin, T. M.; Gross, R. S.; Heflin, M. B.; Hurst, K. J.; Parker, J. W.; Wu, X.; Altamimi, Z.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">255</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/3796610"> <span id="translatedtitle">Two distant and <span class="hlt">precisely</span> <span class="hlt">positioned</span> domains promote transcription of Xenopus laevis rRNA genes: analysis with linker-scanning mutants.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">To examine the internal organization of the promoter of the Xenopus laevis rRNA gene, we constructed a series of linker-scanning mutants that traverse the rDNA initiation region. The mutant genes, which have 3 to 11 clustered base substitutions set within an otherwise unaltered rDNA promoter sequence, were injected into Xenopus oocyte nuclei, and their transcriptional capacity was assessed by S1 nuclease analysis of the resultant RNA. The data demonstrate that there are two essential promoter domains, the distal boundaries of which coincide with the promoter boundaries established previously by analysis of 5' and 3' deletion mutants. The upstream promoter domain is relatively small and extends from residues ca. -140 to -128. The downstream domain is considerably larger, encompassing residues ca. -36 to +10, and exactly corresponds in both size and <span class="hlt">position</span> to the mammalian minimal promoter region. The Xenopus rDNA sequence between these two essential domains has a much smaller effect on the level of transcriptional initiation. In light of the fact that a large portion of this intervening region consists of a segment (residues -114 to -72) that is duplicated many times in the upstream spacer to form an rDNA enhancer sequence, it is noteworthy that a "-115/-77 linker scanner," in which virtually this entire segment is replaced by a polylinker sequence, has full promoter activity in the injected Xenopus borealis oocytes. Analysis of a parallel series of spacing change linker-scanning mutants revealed the unexpected result that the relative <span class="hlt">positions</span> of the upstream and downstream promoter domains are very critical: all spacing alterations of more than 2 base pairs within this 100-base-pair region virtually abolish promoter activity. We conclude that the factors that bind to these two distant promoter domains must interact in a very <span class="hlt">precise</span> stereospecific manner. PMID:3796610</p> <div class="credits"> <p class="dwt_author">Windle, J J; Sollner-Webb, B</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">256</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.colorado.edu/GeolSci/faculty/molnarpdf/2004Luxembourg.BeavanNZ-VertGPS.pdf"> <span id="translatedtitle">To appear in: Cahiers de Centre Europen de Godynamique et Sismologie, Proceedings of the Workshop: The state of GPS vertical <span class="hlt">positioning</span> <span class="hlt">precision</span>: Separation of earth processes by space geodesy, ed. T. van Dam, vol. 24, 2004.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">of the Workshop: The state of GPS vertical <span class="hlt">positioning</span> <span class="hlt">precision</span>: Separation of earth processes by space geodesy vertical movement across the mountain range. An error model that accounts for both white noise and power. The estimated vertical rates define a reasonably smooth profile across the range, though there are apparently</p> <div class="credits"> <p class="dwt_author">Mojzsis, Stephen J.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">257</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011JASS...28...55C"> <span id="translatedtitle"><span class="hlt">Precision</span> Assessment of Near Real Time <span class="hlt">Precise</span> Orbit Determination for Low Earth Orbiter</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The <span class="hlt">precise</span> orbit determination (POD) of low earth orbiter (LEO) has complied with its required <span class="hlt">positioning</span> accuracy by the double-differencing of observations between International GNSS Service (IGS) and LEO to eliminate the common clock error of the global <span class="hlt">positioning</span> system (GPS) satellites and receiver. Using this method, we also have achieved the 1 m <span class="hlt">positioning</span> accuracy of Korea Multi-Purpose Satellite (KOMPSAT)-2. However double-differencing POD has huge load of processing the global network of lots of ground stations because LEO turns around the Earth with rapid velocity. And both the centimeter accuracy and the near real time (NRT) processing have been needed in the LEO POD applications--atmospheric sounding or urgent image processing--as well as the surveying. An alternative to differential GPS for high accuracy NRT POD is <span class="hlt">precise</span> <span class="hlt">point</span> <span class="hlt">positioning</span> (PPP) to use measurements from one satellite receiver only, to replace the broadcast navigation message with <span class="hlt">precise</span> post processed values from IGS, and to have phase measurements of dual frequency GPS receiver. PPP can obtain <span class="hlt">positioning</span> accuracy comparable to that of differential <span class="hlt">positioning</span>. KOMPSAT-5 has a <span class="hlt">precise</span> dual frequency GPS flight receiver (integrated GPS and occultation receiver, IGOR) to satisfy the accuracy requirements of 20 cm <span class="hlt">positioning</span> accuracy for highly <span class="hlt">precise</span> synthetic aperture radar image processing and to collect GPS radio occultation measurements for atmospheric sounding. In this paper we obtained about 3-5 cm <span class="hlt">positioning</span> accuracies using the real GPS data of the Gravity Recover and Climate Experiment (GRACE) satellites loaded the Blackjack receiver, a predecessor of IGOR. And it is important to reduce the latency of orbit determination processing in the NRT POD. This latency is determined as the volume of GPS measurements. Thus changing the sampling intervals, we show their latency to able to reduce without the <span class="hlt">precision</span> degradation as the assessment of their <span class="hlt">precision</span>.</p> <div class="credits"> <p class="dwt_author">Choi, Jong-Yeoun; Lee, Sang-Jeong</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">258</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50718432"> <span id="translatedtitle">Application of Real-Time <span class="hlt">Precise</span> <span class="hlt">Point</span> <span class="hlt">Positioning</span> and GIS for Rail Track Deformation Monitoring of the Qinghai-Tibet Railway</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Qinghai-Tibet railway is the highest railway in the world. The operational conditions of this railway are very harsh, such as occurrence of earthquake, potential melting of frozen soil, and severely cold and thin air. Real time monitoring the deformation of the railway system for maintaining safe operation has posed a big challenge. Extensive document review conducted by the authors</p> <div class="credits"> <p class="dwt_author">R. Gao; X. Meng; J. Geng; H.-S. Yu; L. Xu</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">259</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=parallax&pg=2&id=ED020118"> <span id="translatedtitle">MEASUREMENT AND <span class="hlt">PRECISION</span>, EXPERIMENTAL VERSION.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">THIS DOCUMENT IS AN EXPERIMENTAL VERSION OF A PROGRAMED TEXT ON MEASUREMENT AND <span class="hlt">PRECISION</span>. PART I CONTAINS 24 FRAMES DEALING WITH <span class="hlt">PRECISION</span> AND SIGNIFICANT FIGURES ENCOUNTERED IN VARIOUS MATHEMATICAL COMPUTATIONS AND MEASUREMENTS. PART II BEGINS WITH A BRIEF SECTION ON EXPERIMENTAL DATA, COVERING SUCH <span class="hlt">POINTS</span> AS (1) ESTABLISHING THE ZERO <span class="hlt">POINT</span>, (2)…</p> <div class="credits"> <p class="dwt_author">Harvard Univ., Cambridge, MA. Harvard Project Physics.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">260</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/20079385"> <span id="translatedtitle">The differences in the isoelectric <span class="hlt">points</span> of biofilm-<span class="hlt">positive</span> and biofilm-negative Candida parapsilosis strains.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The isoelectric <span class="hlt">points</span> of 39 Candida parapsilosis strains were determined by means of capillary isoelectric focusing. The value of the isoelectric <span class="hlt">point</span> corresponded well with cell surface hydrophobicity, as well as with the ability to form biofilm in these yeasts. PMID:20079385</p> <div class="credits"> <p class="dwt_author">Ruzicka, Filip; Horka, Marie; Hola, Veronika; Kubesova, Anna; Pavlik, Tomas; Votava, Miroslav</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-03-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_12");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a 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class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_13");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return 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title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">261</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/872869"> <span id="translatedtitle"><span class="hlt">Precision</span> displacement reference system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A <span class="hlt">precision</span> displacement reference system is described, which enables real time accountability over the applied displacement feedback system to <span class="hlt">precision</span> machine tools, <span class="hlt">positioning</span> mechanisms, motion devices, and related operations. As independent measurements of tool location is taken by a displacement feedback system, a rotating reference disk compares feedback counts with performed motion. These measurements are compared to characterize and analyze real time mechanical and control performance during operation.</p> <div class="credits"> <p class="dwt_author">Bieg, Lothar F. (Albuquerque, NM); Dubois, Robert R. (Albuquerque, NM); Strother, Jerry D. (Edgewood, NM)</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-02-22</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">262</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005SPIE.5633...66Z"> <span id="translatedtitle">Study on the special vision sensor for detecting <span class="hlt">position</span> error in robot <span class="hlt">precise</span> TIG welding of some key part of rocket engine</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Rocket engine is a hard-core part of aerospace transportation and thrusting system, whose research and development is very important in national defense, aviation and aerospace. A novel vision sensor is developed, which can be used for error detecting in arc length control and seam tracking in <span class="hlt">precise</span> pulse TIG welding of the extending part of the rocket engine jet tube. The vision sensor has many advantages, such as imaging with high quality, compactness and multiple functions. The optics design, mechanism design and circuit design of the vision sensor have been described in detail. Utilizing the mirror imaging of Tungsten electrode in the weld pool, a novel method is proposed to detect the arc length and seam tracking error of Tungsten electrode to the center line of joint seam from a single weld image. A calculating model of the method is proposed according to the relation of the Tungsten electrode, weld pool, the mirror of Tungsten electrode in weld pool and joint seam. The new methodologies are given to detect the arc length and seam tracking error. Through analyzing the results of the experiments, a system error modifying method based on a linear function is developed to improve the detecting <span class="hlt">precise</span> of arc length and seam tracking error. Experimental results show that the final <span class="hlt">precision</span> of the system reaches 0.1 mm in detecting the arc length and the seam tracking error of Tungsten electrode to the center line of joint seam.</p> <div class="credits"> <p class="dwt_author">Zhang, Wenzeng; Chen, Nian; Wang, Bin; Cao, Yipeng</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">263</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=McARDLE&pg=5&id=EJ958606"> <span id="translatedtitle">A Case Example of the Implementation of Schoolwide <span class="hlt">Positive</span> Behavior Support in a High School Setting Using Change <span class="hlt">Point</span> Test Analysis</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">The purpose of this case study was to expand the literature base regarding the application of high school schoolwide <span class="hlt">positive</span> behavior support in an urban setting for practitioners and policymakers to address behavior issues. In addition, the study describes the use of the Change <span class="hlt">Point</span> Test as a method for analyzing time series data that are…</p> <div class="credits"> <p class="dwt_author">Bohanon, Hank; Fenning, Pamela; Hicks, Kira; Weber, Stacey; Thier, Kimberly; Aikins, Brigit; Morrissey, Kelly; Briggs, Alissa; Bartucci, Gina; McArdle, Lauren; Hoeper, Lisa; Irvin, Larry</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">264</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://files.eric.ed.gov/fulltext/ED539402.pdf"> <span id="translatedtitle">Response to the DIAC Discussion Paper: "Review of the General Skilled Migration <span class="hlt">Points</span> Test". Go8 <span class="hlt">Position</span> Paper</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">The Group of Eight (Go8) applauds the government's intention to comprehensively reform the skilled migration program, and it welcomes the opportunity to submit this response to the General Skilled Migration (GSM) <span class="hlt">Points</span> Test Discussion Paper. The Go8 has argued for some time that it is inappropriate to link international education to the skilled…</p> <div class="credits"> <p class="dwt_author">Group of Eight (NJ1), 2010</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">265</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004ESASP.555E..69M"> <span id="translatedtitle"><span class="hlt">Precision</span> Adjustable Liquid Regulator (ALR)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A passive mechanical regulator has been developed for the control of fuel or oxidizer flow to a 450N class bipropellant engine for use on commercial and interplanetary spacecraft. There are several potential benefits to the propulsion system, depending on mission requirements and spacecraft design. This system design enables more <span class="hlt">precise</span> control of main engine mixture ratio and inlet pressure, and simplifies the pressurization system by transferring the function of main engine flow rate control from the pressurization/propellant tank assemblies, to a single component, the ALR. This design can also reduce the thermal control requirements on the propellant tanks, avoid costly Qualification testing of biprop engines for missions with more stringent requirements, and reduce the overall propulsion system mass and power usage. In order to realize these benefits, the ALR must meet stringent design requirements. The main advantage of this regulator over other units available in the market is that it can regulate about its nominal set <span class="hlt">point</span> to within +/-0.85%, and change its regulation set <span class="hlt">point</span> in flight +/-4% about that nominal <span class="hlt">point</span>. The set <span class="hlt">point</span> change is handled actively via a stepper motor driven actuator, which converts rotary into linear motion to affect the spring preload acting on the regulator. Once adjusted to a particular set <span class="hlt">point</span>, the actuator remains in its final <span class="hlt">position</span> unpowered, and the regulator passively maintains outlet pressure. The very <span class="hlt">precise</span> outlet regulation pressure is possible due to new technology developed by Moog, Inc. which reduces typical regulator mechanical hysteresis to near zero. The ALR requirements specified an outlet pressure set <span class="hlt">point</span> range from 225 to 255 psi, and equivalent water flow rates required were in the 0.17 lb/sec range. The regulation output pressure is maintained at +/-2 psi about the set <span class="hlt">point</span> from a P (delta or differential pressure) of 20 to over 100 psid. Maximum upstream system pressure was specified at 320 psi. The regulator is fault tolerant in that it was purposely designed with no shutoff capability, such that the minimum flow <span class="hlt">position</span> of the poppet still allows the subsystem to provide adequate flow to the main engine for basic operation.</p> <div class="credits"> <p class="dwt_author">Meinhold, R.; Parker, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">266</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3872045"> <span id="translatedtitle">Effects of age, sex and arm on the <span class="hlt">precision</span> of arm <span class="hlt">position</span> sense--left-arm superiority in healthy right-handers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Position</span> sense is an important proprioceptive ability. Disorders of arm <span class="hlt">position</span> sense (APS) often occur after unilateral stroke, and are associated with a negative functional outcome. In the present study we assessed horizontal APS by measuring angular deviations from a visually defined target separately for each arm in a large group of healthy subjects. We analyzed the accuracy and instability of horizontal APS as a function of age, sex and arm. Subjects were required to specify verbally the <span class="hlt">position</span> of their unseen arm on a 0-90° circuit by comparing the current <span class="hlt">position</span> with the target <span class="hlt">position</span> indicated by a LED lamp, while the arm was passively moved by the examiner. Eighty-seven healthy subjects participated in the study, ranging from 20 to 77 years, subdivided into three age groups. The results revealed that APS was not a function of age or sex, but was significantly better in the non-dominant (left) arm in absolute errors (AE) but not in constant errors (CE) across all age groups of right-handed healthy subjects. This indicates a right-hemisphere superiority for left APS in right-handers and neatly fits to the more frequent and more severe left-sided body-related deficits in patients with unilateral stroke (i.e. impaired APS in left spatial neglect, somatoparaphrenia) or in individuals with abnormalities of the right cerebral hemisphere. These clinical issues will be discussed. PMID:24399962</p> <div class="credits"> <p class="dwt_author">Schmidt, Lena; Depper, Lena; Kerkhoff, Georg</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">267</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=SOCIETY+AND+KNOWLEDGE&pg=7&id=EJ821692"> <span id="translatedtitle">Higher Education-to-Work Transitions in the Knowledge Society: The Initial Transition and <span class="hlt">Positional</span> Competition <span class="hlt">Point</span> of View</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">This article presents an analysis of the higher education-to-work transition from the perspective of the competition for job <span class="hlt">positions</span> between students and degree holders. The conceptual framework used addresses two factors influencing the success of policies that aim to support higher education-to-work transition of youth in a knowledge society:…</p> <div class="credits"> <p class="dwt_author">Lindberg, Matti</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">268</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.cosmic.ucar.edu/~braunj/papers/jaot_swv2003.pdf"> <span id="translatedtitle">Comparisons of Line-of-Sight Water Vapor Observations Using the Global <span class="hlt">Positioning</span> System and a <span class="hlt">Pointing</span> Microwave Radiometer</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Line-of-sight measurements of integrated water vapor from a global <span class="hlt">positioning</span> system (GPS) receiver and a microwave radiometer are compared. These two instruments were collocated at the central facility of the Department of Energy's Atmospheric Radiation Measurement Program's Southern Great Plains region, near Lamont, Oklahoma. The comparison was made using 47 days of observations in May and June of 2000. Weather</p> <div class="credits"> <p class="dwt_author">John Braun; Christian Rocken; James Liljegren</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">269</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/20850142"> <span id="translatedtitle">Assessment of residual error in liver <span class="hlt">position</span> using kV cone-beam computed tomography for liver cancer high-<span class="hlt">precision</span> radiation therapy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Purpose: To evaluate the residual error in liver <span class="hlt">position</span> using breath-hold kilovoltage (kV) cone-beam computed tomography (CT) following on-line orthogonal megavoltage (MV) image-guided breath-hold liver cancer conformal radiotherapy. Methods and Materials: Thirteen patients with liver cancer treated with 6-fraction breath-hold conformal radiotherapy were investigated. Before each fraction, orthogonal MV images were obtained during exhale breath-hold, with repositioning for offsets >3 mm, using the diaphragm for cranio-caudal (CC) alignment and vertebral bodies for medial-lateral (ML) and anterior posterior (AP) alignment. After repositioning, repeat orthogonal MV images, orthogonal kV fluoroscopic movies, and kV cone-beam CTs were obtained in exhale breath-hold. The cone-beam CT livers were registered to the planning CT liver to obtain the residual setup error in liver <span class="hlt">position</span>. Results: After repositioning, 78 orthogonal MV image pairs, 61 orthogonal kV image pairs, and 72 kV cone-beam CT scans were obtained. Population random setup errors ({sigma}) in liver <span class="hlt">position</span> were 2.7 mm (CC), 2.3 mm (ML), and 3.0 mm (AP), and systematic errors ({sigma}) were 1.1 mm, 1.9 mm, and 1.3 mm in the superior, medial, and posterior directions. Liver offsets >5 mm were observed in 33% of cases; offsets >10 mm and liver deformation >5 mm were observed in a minority of patients. Conclusions: Liver <span class="hlt">position</span> after radiation therapy guided with MV orthogonal imaging was within 5 mm of planned <span class="hlt">position</span> in the majority of patients. kV cone-beam CT image guidance should improve accuracy with reduced dose compared with orthogonal MV image guidance for liver cancer radiation therapy.</p> <div class="credits"> <p class="dwt_author">Hawkins, Maria A. [Radiation Medicine Program, Princess Margaret Hospital, Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Brock, Kristy K. [Radiation Medicine Program, Princess Margaret Hospital, Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Eccles, Cynthia [Radiation Medicine Program, Princess Margaret Hospital, Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Moseley, Douglas [Radiation Medicine Program, Princess Margaret Hospital, Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Jaffray, David [Radiation Medicine Program, Princess Margaret Hospital, Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Dawson, Laura A. [Radiation Medicine Program, Princess Margaret Hospital, Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada)]. E-mail: laura.dawson@rmp.uhn.on.ca</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">270</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/7281334"> <span id="translatedtitle">Development of a GPS-aided motion measurement, <span class="hlt">pointing</span>, and stabilization system for a Synthetic Aperture Radar. [Global <span class="hlt">Positioning</span> System (GPS)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">An advanced Synthetic Aperture Radar Motion Compensation System has been developed by Sandia National Laboratories (SNL). The system includes a miniaturized high accuracy ring laser gyro inertial measurement unit, a three axis gimbal <span class="hlt">pointing</span> and stabilization assembly, a differential Global <span class="hlt">Positioning</span> System (GPS) navigation aiding system, and a pilot guidance system. The system provides several improvements over previous SNL motion compensation systems and is capable of antenna stabilization to less than 0.01 degrees RMS and absolute <span class="hlt">position</span> measurement to less than 5.0 meters RMS. These accuracies have been demonstrated in recent flight testing aboard a DHC-6-300 Twin Otter'' aircraft.</p> <div class="credits"> <p class="dwt_author">Fellerhoff, J.R.; Kohler, S.M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">271</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20100010934&hterms=python+filters&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dpython%2Bfilters"> <span id="translatedtitle">Mapped Landmark Algorithm for <span class="hlt">Precision</span> Landing</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A report discusses a computer vision algorithm for <span class="hlt">position</span> estimation to enable <span class="hlt">precision</span> landing during planetary descent. The Descent Image Motion Estimation System for the Mars Exploration Rovers has been used as a starting <span class="hlt">point</span> for creating code for <span class="hlt">precision</span>, terrain-relative navigation during planetary landing. The algorithm is designed to be general because it handles images taken at different scales and resolutions relative to the map, and can produce mapped landmark matches for any planetary terrain of sufficient texture. These matches provide a measurement of horizontal <span class="hlt">position</span> relative to a known landing site specified on the surface map. Multiple mapped landmarks generated per image allow for automatic detection and elimination of bad matches. Attitude and <span class="hlt">position</span> can be generated from each image; this image-based attitude measurement can be used by the onboard navigation filter to improve the attitude estimate, which will improve the <span class="hlt">position</span> estimates. The algorithm uses normalized correlation of grayscale images, producing <span class="hlt">precise</span>, sub-pixel images. The algorithm has been broken into two sub-algorithms: (1) FFT Map Matching (see figure), which matches a single large template by correlation in the frequency domain, and (2) Mapped Landmark Refinement, which matches many small templates by correlation in the spatial domain. Each relies on feature selection, the homography transform, and 3D image correlation. The algorithm is implemented in C++ and is rated at Technology Readiness Level (TRL) 4.</p> <div class="credits"> <p class="dwt_author">Johnson, Andrew; Ansar, Adnan; Matthies, Larry</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">272</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/949683"> <span id="translatedtitle">Comparisons of line-of-sight water vapor observations using the global <span class="hlt">positioning</span> system and a <span class="hlt">pointing</span> microwave radiometer.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Line-of-sight measurements of integrated water vapor from a global <span class="hlt">positioning</span> system (GPS) receiver and a microwave radiometer are compared. These two instruments were collocated at the central facility of the Department of Energy's Atmospheric Radiation Measurement Program's Southern Great Plains region, near Lamont, Oklahoma. The comparison was made using 47 days of observations in May and June of 2000. Weather conditions during this time period were variable with total integrated water vapor ranging from less than 10 to more than 50 mm. To minimize errors in the microwave radiometer observations, observations were compared during conditions when the liquid water measured by the radiometer was less than 0.1 mm. The linear correlation of the observations between the two instruments is 0.99 with a root-mean-square difference of the GPS water vapor to a linear fit of the microwave radiometer of 1.3 mm. The results from these comparisons are used to evaluate the ability of networks of GPS receivers to measure instantaneous line-of-sight integrals of water vapor. A discussion and analysis is provided regarding the additional information of the water vapor field contained in these observations compared to time- and space-averaged zenith and gradient measurements.</p> <div class="credits"> <p class="dwt_author">Braun, J.; Rocken, C.; Liljegren, J. C.; Environmental Research; Univ. Corporation for Atmospheric Research</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">273</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3920874"> <span id="translatedtitle"><span class="hlt">Position</span>-addressable digital laser scanning <span class="hlt">point</span> fluorescence microscopy with a Blu-ray disk pickup head</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">A compact and <span class="hlt">position</span>-addressable blue ray scanning microscope (BSM) based on a commercially available Blu-ray disk pickup head (PUH) is developed for cell imaging with high resolution and low cost. The BSM comprises two objective lenses with numerical apertures (NAs) of 0.85 and 0.6 for focusing blue and red laser beams, respectively, on the sample slide. The blue and red laser beams are co-located adjacent to each other and move synchronously. A specially designed sample slide is used with a sample area and an address-patterned area for sample holding and address recognition, respectively. The blue laser beam is focused on the sample area and is used for fluorescent excitation and image capturing, whereas the red laser beam is focused on the address-patterned area and is used for address recognition and dynamic focusing. The address-patterned area is divided into 310 sectors. The cell image of each sector of the sampling area has a corresponding address pattern. Fluorescence images of monkey-derived kidney epithelial cells and fibroblast cells in which the F-actin is stained with fluorophore phalloidin CF 405 are measured by the BSM, with results comparable to those measured by a Leica TCS CP2 confocal microscope. The cell image of an area of interest can be easily tracked based on the coded address, and a large-area sample image can be accurately reconstructed from the sector images. PMID:24575338</p> <div class="credits"> <p class="dwt_author">Tsai, Rung-Ywan; Chen, Jung-Po; Lee, Yuan-Chin; Huang, Chun-Chieh; Huang, Tai-Ting; Chiang, Hung-Chih; Cheng, Chih-Ming; Lo, Feng-Hsiang; Chang, Sheng-Li; Weng, Kuo-Yao; Chung, Lung-Pin; Chen, Jyh-Chern; Tiao, Golden</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">274</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20040110726&hterms=tbi&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dtbi"> <span id="translatedtitle">Instrument Attitude <span class="hlt">Precision</span> Control</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A novel approach is presented in this paper to analyze attitude <span class="hlt">precision</span> and control for an instrument gimbaled to a spacecraft subject to an internal disturbance caused by a moving component inside the instrument. Nonlinear differential equations of motion for some sample cases are derived and solved analytically to gain insight into the influence of the disturbance on the attitude <span class="hlt">pointing</span> error. A simple control law is developed to eliminate the instrument <span class="hlt">pointing</span> error caused by the internal disturbance. Several cases are presented to demonstrate and verify the concept presented in this paper.</p> <div class="credits"> <p class="dwt_author">Juang, Jer-Nan</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">275</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/41136652"> <span id="translatedtitle">Using Global <span class="hlt">Positioning</span> System techniques in landslide monitoring</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The <span class="hlt">precise</span> determination of <span class="hlt">point</span> coordinates with conventional Global <span class="hlt">Positioning</span> System (GPS) techniques often required observation times of one to several hours. In the last few years, new GPS methods have been developed (among them, the fast-static and real time kinematic), with higher productivity and good theoretical <span class="hlt">precision</span>. The main objective of this paper is to ascertain the performance of</p> <div class="credits"> <p class="dwt_author">Josep A. Gili; Jordi Corominas; Joan Rius</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">276</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/15213311"> <span id="translatedtitle">Sweeping <span class="hlt">Points</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Given a set of <span class="hlt">points</span> in the plane, and a sweep-line as a tool, what is best way to move the <span class="hlt">points</span> to a target <span class="hlt">point</span> using\\u000a a sequence of sweeps? In a sweep, the sweep-line is placed at a start <span class="hlt">position</span> somewhere in the plane, then moved orthogonally\\u000a and continuously to another parallel end <span class="hlt">position</span>, and then lifted from</p> <div class="credits"> <p class="dwt_author">Adrian Dumitrescu; Minghui Jiang</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">277</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://repository.tamu.edu/handle/1969.1/85854"> <span id="translatedtitle"><span class="hlt">Precision</span> mechatronics lab robot development</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">based mobile robot. The principal goal of this work was the demonstration of the <span class="hlt">Precision</span> Mechatronics Lab (PML) robot. This robot should be capable of traversing any known distance while maintaining a minimal <span class="hlt">position</span> error. An optical correction...</p> <div class="credits"> <p class="dwt_author">Rogers, Adam Gregory</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-10-10</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">278</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://repository.tamu.edu/handle/1969.1/ETD-TAMU-2090"> <span id="translatedtitle"><span class="hlt">Precision</span> mechatronics lab robot development</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">based mobile robot. The principal goal of this work was the demonstration of the <span class="hlt">Precision</span> Mechatronics Lab (PML) robot. This robot should be capable of traversing any known distance while maintaining a minimal <span class="hlt">position</span> error. An optical correction...</p> <div class="credits"> <p class="dwt_author">Rogers, Adam Gregory</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-05-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">279</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19920014298&hterms=CSR&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DCSR"> <span id="translatedtitle"><span class="hlt">Precision</span> GPS ephemerides and baselines</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Based on the research, the area of <span class="hlt">precise</span> ephemerides for GPS satellites, the following observations can be made pertaining to the status and future work needed regarding orbit accuracy. There are several aspects which need to be addressed in discussing determination of <span class="hlt">precise</span> orbits, such as force models, kinematic models, measurement models, data reduction/estimation methods, etc. Although each one of these aspects was studied at CSR in research efforts, only <span class="hlt">points</span> pertaining to the force modeling aspect are addressed.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">280</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.teachengineering.org/view_activity.php?url=collection/cub_/activities/cub_navigation/cub_navigation_lesson08_activity1.xml"> <span id="translatedtitle">State Your <span class="hlt">Position</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">To navigate, you must know roughly where you stand relative to your designation, so you can head in the right direction. In locations where landmarks are not available to help navigate (in deserts, on seas), objects in the sky are the only reference <span class="hlt">points</span>. While celestial objects move fairly predictably, and rough longitude is not too difficult to find, it is not a simple matter to determine latitude and <span class="hlt">precise</span> <span class="hlt">positions</span>. In this activity, students investigate the uses and advantages of modern GPS for navigation.</p> <div class="credits"> <p class="dwt_author">Integrated Teaching And Learning Program</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_13");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' 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showDiv("page_16");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">281</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/0805.2153v1"> <span id="translatedtitle"><span class="hlt">Precision</span> Astrometry with Adaptive Optics</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">We investigate the limits of ground-based astrometry with adaptive optics using the core of the Galactic globular cluster M5. Adaptive optics systems provide near diffraction-limit imaging with the world's largest telescopes. The substantial improvement in both resolution and signal-to-noise ratio enables high-<span class="hlt">precision</span> astrometry from the ground. We describe the dominant systematic errors that typically limit ground-based differential astrometry, and enumerate observational considerations for mitigating their effects. After implementing these measures, we find that the dominant limitation on astrometric performance in this experiment is caused by tilt anisoplanatism. We then present an optimal estimation technique for measuring the <span class="hlt">position</span> of one star relative to a grid of reference stars in the face of this correlated random noise source. Our methodology has the advantage of reducing the astrometric errors as the square root of time and faster than the square root of the number of reference stars -- effectively eliminating noise caused by atmospheric tilt to the <span class="hlt">point</span> that astrometric performance is limited by centering accuracy. Using 50 reference stars we demonstrate single-epoch astrometric <span class="hlt">precision</span> of ~ 1 mas in 1 second, decreasing to < 100 microarcseconds in 2 minutes of integration time at the Hale 200-inch telescope. We also show that our astrometry is accurate to <~ 100 microarcseconds for observations separated by 2 months. Finally, we discuss the limits and potential of differential astrometry with current and next generation large aperture telescopes. At this level of accuracy, numerous astrometric applications become accessible, including planet detection, astrometric microlensing signatures, and kinematics of distant Galactic stellar populations.</p> <div class="credits"> <p class="dwt_author">P. B. Cameron; M. C. Britton; S. R. Kulkarni</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-05-14</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">282</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/270670"> <span id="translatedtitle"><span class="hlt">Precision</span> guided parachute LDRD final report</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This report summarizes the results of the <span class="hlt">Precision</span> Guided Parachute LDRD, a two year program at Sandia National Laboratories which developed a Global <span class="hlt">Positioning</span> System (GPS) guided parachute capable of autonomous flight and landings. A detailed computer model of a gliding parachute was developed for software only simulations. A hardware in-the-loop simulator was developed and used for flight package system integration and design validation. Initial parachute drop tests were conducted at Sandia`s Coyote Canyon Cable Facility, followed by a series of airdrops using Ross Aircraft`s Twin Otter at the Burris Ranch Drop Zone. Final flights demonstrated in-flight wind estimation and the capability to fly a commanded heading. In the past, the cost and logistical complexity of an initial navigation system ruled out actively guiding a parachute. The advent of the low-cost, light-weight Global <span class="hlt">Positioning</span> System (GPS) has eliminated this barrier. By using GPS <span class="hlt">position</span> and velocity measurements, a guided parachute can autonomously steer itself to a targeted <span class="hlt">point</span> on the ground through the use of control drums attached to the control lanyards of the parachute. By actively correcting for drop <span class="hlt">point</span> errors and wind drift, the guidance accuracy of this system should be on the order of GPS <span class="hlt">position</span> errors. This would be a significant improvement over unguided airdrops which may have errors of a mile or more.</p> <div class="credits"> <p class="dwt_author">Gilkey, J.C. [Sandia National Labs., Albuquerque, NM (United States). Aided Navigation and Remote Sensing Dept.</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">283</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AAS...21840604K"> <span id="translatedtitle">Fiber Scrambling for High <span class="hlt">Precision</span> Spectrographs</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The detection of Earth-like exoplanets with the radial velocity method requires extreme Doppler <span class="hlt">precision</span> and long-term stability in order to measure tiny reflex velocities in the host star. Recent planet searches have led to the detection of so called "super-Earths” (up to a few Earth masses) that induce radial velocity changes of about 1 m/s. However, the detection of true Earth analogs requires a <span class="hlt">precision</span> of 10 cm/s. One of the largest factors limiting Doppler <span class="hlt">precision</span> is variation in the <span class="hlt">Point</span> Spread Function (PSF) from observation to observation due to changes in the illumination of the slit and spectrograph optics. Thus, this stability has become a focus of current instrumentation work. Fiber optics have been used since the 1980's to couple telescopes to high-<span class="hlt">precision</span> spectrographs, initially for simpler mechanical design and control. However, fiber optics are also naturally efficient scramblers. Scrambling refers to a fiber's ability to produce an output beam independent of input. Our research is focused on characterizing the scrambling properties of several types of fibers, including circular, square and octagonal fibers. By measuring the intensity distribution after the fiber as a function of input beam <span class="hlt">position</span>, we can simulate guiding errors that occur at an observatory. Through this, we can determine which fibers produce the most uniform outputs for the severest guiding errors, improving the PSF and allowing sub-m/s <span class="hlt">precision</span>. However, extensive testing of fibers of supposedly identical core diameter, length and shape from the same manufacturer has revealed the "personality” of individual fibers. Personality describes differing intensity patterns for supposedly duplicate fibers illuminated identically. Here, we present our results on scrambling characterization as a function of fiber type, while studying individual fiber personality.</p> <div class="credits"> <p class="dwt_author">Kaplan, Zachary; Spronck, J. F. P.; Fischer, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">284</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19680000505&hterms=Plung&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DPlung"> <span id="translatedtitle">High-torque <span class="hlt">precision</span> stepping drive</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Stepping drive has been designed for <span class="hlt">precise</span> incremental angular <span class="hlt">positioning</span> of scale models of spacecraft about a horizontal axis in order to accurately measure antenna receiving and transmitting characteristics. <span class="hlt">Positioning</span> is insured by spring-loaded, self-locking plungers.</p> <div class="credits"> <p class="dwt_author">Kaspareck, W. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1968-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">285</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/45479176"> <span id="translatedtitle">Real Sky Tests of Star-Tracker-Based Attitude Determination System for Earth <span class="hlt">Pointing</span> Spacecraft</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Earth-<span class="hlt">pointing</span> and polar-orbiting spacecraft, the Advanced Land Observing Satellite (ALOS), has a <span class="hlt">precision</span> attitude determination system exploiting measurements of a <span class="hlt">precision</span> star tracker and an inertial reference unit, and controls its attitude, based on the attitude estimates. The star tracker provides the <span class="hlt">positions</span> and magnitudes of stars. The attitude control system's computer identifies stars which enter the star tracker's FOV</p> <div class="credits"> <p class="dwt_author">Takanori Iwata; Eiji Hirokawa; Hiroki Hoshino; Takeshi Yoshizawa; Koshi Sato; Isamu Higashino</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">286</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/873834"> <span id="translatedtitle"><span class="hlt">Precision</span> powder feeder</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A new class of <span class="hlt">precision</span> powder feeders is disclosed. These feeders provide a <span class="hlt">precision</span> flow of a wide range of powdered materials, while remaining robust against jamming or damage. These feeders can be <span class="hlt">precisely</span> controlled by feedback mechanisms.</p> <div class="credits"> <p class="dwt_author">Schlienger, M. Eric (Albuquerque, NM); Schmale, David T. (Albuquerque, NM); Oliver, Michael S. (Sandia Park, NM)</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-07-10</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">287</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/867630"> <span id="translatedtitle"><span class="hlt">Precision</span> contour gage</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">An apparatus for gaging the contour of a machined part includes a rotary slide assembly, a kinematic mount to move the apparatus into and out of <span class="hlt">position</span> for measuring the part while the part is still on the machining apparatus, a linear probe assembly with a suspension arm and a probe assembly including as probe tip for providing a measure of linear displacement of the tip on the surface of the part, a means for changing relative <span class="hlt">positions</span> between the part and the probe tip, and a means for recording data <span class="hlt">points</span> representing linear <span class="hlt">positions</span> of the probe tip at prescribed rotation intervals in the <span class="hlt">position</span> changes between the part and the probe tip.</p> <div class="credits"> <p class="dwt_author">Bieg, Lothar F. (Louisville, CO)</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-12-11</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">288</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3629835"> <span id="translatedtitle">Probing the Metabotropic Glutamate Receptor 5 (mGlu5) <span class="hlt">Positive</span> Allosteric Modulator (PAM) Binding Pocket: Discovery of <span class="hlt">Point</span> Mutations That Engender a "Molecular Switch" in PAM Pharmacology</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Positive</span> allosteric modulation of metabotropic glutamate receptor subtype 5 (mGlu5) is a promising novel approach for the treatment of schizophrenia and cognitive disorders. Allosteric binding sites are topographically distinct from the endogenous ligand (orthosteric) binding site, allowing for co-occupation of a single receptor with the endogenous ligand and an allosteric modulator. Negative allosteric modulators (NAMs) inhibit and <span class="hlt">positive</span> allosteric modulators (PAMs) enhance the affinity and/or efficacy of the orthosteric agonist. The molecular determinants that govern mGlu5 modulator affinity versus cooperativity are not well understood. Focusing on the modulators based on the acetylene scaffold, we sought to determine the molecular interactions that contribute to PAM versus NAM pharmacology. Generation of a comparative model of the transmembrane-spanning region of mGlu5 served as a tool to predict and interpret the impact of mutations in this region. Application of an operational model of allosterism allowed for determination of PAM and NAM affinity estimates at receptor constructs that possessed no detectable radioligand binding as well as delineation of effects on affinity versus cooperativity. Novel mutations within the transmembrane domain (TM) regions were identified that had differential effects on acetylene PAMs versus 2-methyl-6-(phenylethynyl)-pyridine, a prototypical NAM. Three conserved amino acids (Y658, T780, and S808) and two nonconserved residues (P654 and A809) were identified as key determinants of PAM activity. Interestingly, we identified two <span class="hlt">point</span> mutations in TMs 6 and 7 that, when mutated, engender a mode switch in the pharmacology of certain PAMs. PMID:23444015</p> <div class="credits"> <p class="dwt_author">Gregory, Karen J.; Nguyen, Elizabeth D.; Reiff, Sean D.; Squire, Emma F.; Stauffer, Shaun R.; Lindsley, Craig W.; Meiler, Jens</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">289</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013ArtSa..48..141O"> <span id="translatedtitle">The Algorithm for Determining the Coordinates of a <span class="hlt">Point</span> in Three-Dimensional Space by Using the Auxiliary <span class="hlt">Point</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">During the process of satellite navigation, and also in the many tasks of classical <span class="hlt">positioning</span>, we need to calculate the corrections to the initial (or approximate) location of the <span class="hlt">point</span> using <span class="hlt">precise</span> measurement of distances to the permanent <span class="hlt">points</span> of reference (reference <span class="hlt">points</span>). In this paper the authors have provided a way of developing Hausbrandt's equations, on the basis of which the exact coordinates of the <span class="hlt">point</span> in two-dimensional space can be determined by using the computed correction to the coordinates of the auxiliary <span class="hlt">point</span>. The authors developed generalised equations for threedimensional space introducing additional fixed <span class="hlt">point</span> and have presented proof of derived formulas.</p> <div class="credits"> <p class="dwt_author">Oszczak, Bartlomiej; Sitnik, Eliza</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">290</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/6003155"> <span id="translatedtitle"><span class="hlt">Precision</span> Joining Center</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A workshop to obtain input from industry on the establishment of the <span class="hlt">Precision</span> Joining Center (PJC) was held on July 10--12, 1991. The PJC is a center for training Joining Technologists in advanced joining techniques and concepts in order to promote the competitiveness of US industry. The center will be established as part of the DOE Defense Programs Technology Commercialization Initiative, and operated by EG G Rocky Flats in cooperation with the American Welding Society and the Colorado School of Mines Center for Welding and Joining Research. The overall objectives of the workshop were to validate the need for a Joining Technologists to fill the gap between the welding operator and the welding engineer, and to assure that the PJC will train individuals to satisfy that need. The consensus of the workshop participants was that the Joining Technologist is a necessary <span class="hlt">position</span> in industry, and is currently used, with some variation, by many companies. It was agreed that the PJC core curriculum, as presented, would produce a Joining Technologist of value to industries that use <span class="hlt">precision</span> joining techniques. The advantage of the PJC would be to train the Joining Technologist much more quickly and more completely. The proposed emphasis of the PJC curriculum on equipment intensive and hands-on training was judged to be essential.</p> <div class="credits"> <p class="dwt_author">Powell, J.W.; Westphal, D.A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">291</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19870011801&hterms=outerspace&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Douterspace"> <span id="translatedtitle"><span class="hlt">Precision</span> tunable resonant microwave cavity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A tunable microwave cavity containing ionizable metallic vapor or gases and an apparatus for <span class="hlt">precisely</span> <span class="hlt">positioning</span> a microwave coupling tip in the cavity and for <span class="hlt">precisely</span> adjusting at least one dimension of the cavity are disclosed. With this combined structure, resonance may be achieved with various types of ionizable gases. A coaxial probe extends into a microwave cavity through a tube. One end of the tube is retained in a spherical joint attached in the cavity wall. This allows the coaxial probe to be pivotally rotated. The coaxial probe is slideable within the tube thus allowing the probe to be extended toward or retracted from the center of the cavity.</p> <div class="credits"> <p class="dwt_author">Nakanishi, Shigeo (inventor); Calco, Frank S. (inventor); Scarpelli, August R. (inventor)</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">292</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19820024857&hterms=planetary+gear+reducer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dplanetary%2Bgear%2Breducer"> <span id="translatedtitle">Kinematic <span class="hlt">precision</span> of gear trains</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Kinematic <span class="hlt">precision</span> is affected by errors which are the result of either intentional adjustments or accidental defects in manufacturing and assembly of gear trains. A method for the determination of kinematic <span class="hlt">precision</span> of gear trains is described. The method is based on the exact kinematic relations for the contact <span class="hlt">point</span> motions of the gear tooth surfaces under the influence of errors. An approximate method is also explained. Example applications of the general approximate methods are demonstrated for gear trains consisting of involute (spur and helical) gears, circular arc (Wildhaber-Novikov) gears, and spiral bevel gears. Gear noise measurements from a helicopter transmission are presented and discussed with relation to the kinematic <span class="hlt">precision</span> theory.</p> <div class="credits"> <p class="dwt_author">Litvin, F. L.; Goldrich, R. N.; Coy, J. J.; Zaretsky, E. V.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">293</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3334767"> <span id="translatedtitle">Transpulmonary thermodilution assessments: <span class="hlt">precise</span> measurements require a <span class="hlt">precise</span> procedure</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">When incorporating the values of a hemodynamic parameter into the care of patients, the <span class="hlt">precision</span> of the measurement method should always be considered. A prospective analysis in the previous issue of Critical Care showed that the <span class="hlt">precision</span> of transpulmonary thermodilution (TPTD) allows for reliable mean values if a standardised procedure is used. The present finding has a physiological basis, as TPTD requires a more prolonged transit time, which in turn reduces the effects that airway pressure and arrhythmia have on venous return-cardiac output steady states. Moreover, this result suggests that the current accepted threshold value of a 15% increase in cardiac output to identify a <span class="hlt">positive</span> response to a fluid challenge could be reduced in the future. Indeed, this value is mainly related to the <span class="hlt">precision</span> of the pulmonary artery catheter. PMID:21995848</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">294</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.imm.dtu.dk/pubdb/views/edoc_download.php/5929/pdf/imm5929.pdf"> <span id="translatedtitle">On Recall Rate of Interest <span class="hlt">Point</span> Detectors Henrik Aans</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">- dustrial robot arm. The scene surfaces have been scanned using structured light, providing <span class="hlt">precise</span> 3D in relation to the number of interest <span class="hlt">points</span>, the recall rate as a function of camera <span class="hlt">position</span> and light variation, and the sensitivity relative to model parameter change. The overall conclusion is that the Harris</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">295</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/6751700"> <span id="translatedtitle"><span class="hlt">Precision</span> zero-home locator</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A zero-home locator includes a fixed phototransistor switch and a moveable actuator including two symmetrical, opposed wedges, each wedge defining a <span class="hlt">point</span> at which switching occurs. The zero-home location is the average of the <span class="hlt">positions</span> of the <span class="hlt">points</span> defined by the wedges.</p> <div class="credits"> <p class="dwt_author">Stone, W.J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-10-31</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">296</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850007869&hterms=computer-aided+differences+kim&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dcomputer-aided%2Bdifferences%2Bkim"> <span id="translatedtitle"><span class="hlt">Precise</span> control of flexible manipulators</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The design and experimental testing of end <span class="hlt">point</span> <span class="hlt">position</span> controllers for a very flexible one link lightweight manipulator are summarized. The latest upgraded version of the experimental set up, and the basic differences between conventional joint angle feedback and end <span class="hlt">point</span> <span class="hlt">position</span> feedback are described. A general procedure for application of modern control methods to the problem is outlined. The relationship between weighting parameters and the bandwidth and control stiffness of the resulting end <span class="hlt">point</span> <span class="hlt">position</span> closed loop system is shown. It is found that joint rate angle feedback in addition to the primary end <span class="hlt">point</span> <span class="hlt">position</span> sensor is essential for adequate disturbance rejection capability of the closed loop system. The use of a low order multivariable compensator design computer code; called Sandy is documented. A solution to the problem of control mode switching between <span class="hlt">position</span> sensor sets is outlined. The proof of concept for endpoint <span class="hlt">position</span> feedback for a one link flexible manipulator was demonstrated. The bandwidth obtained with the experimental end <span class="hlt">point</span> <span class="hlt">position</span> controller is about twice as fast as the beam's first natural cantilevered frequency, and comes within a factor of four of the absolute physical speed limit imposed by the wave propagation time of the beam.</p> <div class="credits"> <p class="dwt_author">Cannon, R. H., Jr.; Bindford, T. O.; Schmitz, E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">297</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007ASPC..366..209P"> <span id="translatedtitle"><span class="hlt">Precision</span> Photometry for Planetary Transits</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This paper reviews the state of the art in follow-up photometry for planetary transit searches. Three topics are discussed: (1) Photometric monitoring of planets discovered by radial velocity to detect possible transits (2) Follow-up photometry of candidates from photometric transit search to weed out eclipsing binaries and false <span class="hlt">positives</span> (3) High-<span class="hlt">precision</span> light curves of known transiting planets to increase the accuracy on the planet parameters.</p> <div class="credits"> <p class="dwt_author">Pont, F.; Moutou, C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">298</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=cheese&pg=2&id=EJ877113"> <span id="translatedtitle"><span class="hlt">Positive</span> Changes in Perceptions and Selections of Healthful Foods by College Students after a Short-Term <span class="hlt">Point</span>-of-Selection Intervention at a Dining Hall</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Objective: Determine the effects of a short-term, multi-faceted, <span class="hlt">point</span>-of-selection intervention on college students' perceptions and selection of 10 targeted healthful foods in a university dining hall and changes in their self-reported overall eating behaviors. Participants: 104 college students, (age 18-23) completed pre-I and post-I surveys.…</p> <div class="credits"> <p class="dwt_author">Peterson, Sharon; Duncan, Diana Poovey; Null, Dawn Bloyd; Roth, Sara Long; Gill, Lynn</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">299</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003AGUFM.C32A0430R"> <span id="translatedtitle">ICESat <span class="hlt">Precision</span> Orbit Determination</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Following the successful launch of the Ice, Cloud and land Elevation Satellite (ICESat) on January 13, 2003, 00:45 UTC, the GPS receiver on ICESat was turned on successfully on Jan. 17, 2003. High quality GPS data were collected since then to support <span class="hlt">Precision</span> Orbit Determination (POD) activities. ICESat carries Geoscience Laser Altimeter System (GLAS) to measure ice-sheet topography and associated temporal changes, as well as cloud and atmospheric properties. To accomplish the ICESat science objectives, the <span class="hlt">position</span> of the GLAS instrument in space should be determined with an accuracy of 5 cm and 20 cm in radial and horizontal components, respectively. This knowledge is acquired by the POD activities using the data collected by the GPS receiver on ICESat and the ground-based satellite laser ranging (SLR) data. It has been shown from pre-launch POD studies that the gravity model error is the dominant source of ICESat orbit errors. The predicted radial orbit errors at the ICESat orbit (600 km altitude) based on pre-launch gravity models, such as TEG-4 and EGM-96, are 7-15 cm. Performance of these gravity models and the recent gravity models from GRACE on ICESat POD were evaluated. The radial orbit accuracy is approaching 1-2 cm level with the GRACE gravity model. This paper also summarizes POD activities at Center for Space Research (CSR), which is responsible to generate ICESat POD products.</p> <div class="credits"> <p class="dwt_author">Rim, H.; Yoon, S.; Webb, C. E.; Kim, Y.; Schutz, B. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">300</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://disco.ethz.ch/theses/hs09/timesync_gps_report.pdf"> <span id="translatedtitle"><span class="hlt">Precise</span> Time Synchronization for Wireless Sensor Networks using the</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary"><span class="hlt">Precise</span> Time Synchronization for Wireless Sensor Networks using the Global <span class="hlt">Positioning</span> System and wall clock time with the aid of the Global <span class="hlt">Positioning</span> System. Furthermore the proposed approach is.3 The Global <span class="hlt">Positioning</span> System . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.4 nes</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_14");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a 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showDiv("page_17");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">301</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/1410.0149v1"> <span id="translatedtitle"><span class="hlt">Precision</span> luminosity measurements at LHCb</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Measuring cross-sections at the LHC requires the luminosity to be determined accurately at each centre-of-mass energy $\\sqrt{s}$. In this paper results are reported from the luminosity calibrations carried out at the LHC interaction <span class="hlt">point</span> 8 with the LHCb detector for $\\sqrt{s}$ = 2.76, 7 and 8 TeV (proton-proton collisions) and for $\\sqrt{s_{NN}}$ = 5 TeV (proton-lead collisions). Both the "van der Meer scan" and "beam-gas imaging" luminosity calibration methods were employed. It is observed that the beam density profile cannot always be described by a function that is factorizable in the two transverse coordinates. The introduction of a two-dimensional description of the beams improves significantly the consistency of the results. For proton-proton interactions at $\\sqrt{s}$ = 8 TeV a relative <span class="hlt">precision</span> of the luminosity calibration of 1.47% is obtained using van der Meer scans and 1.43% using beam-gas imaging, resulting in a combined <span class="hlt">precision</span> of 1.12%. Applying the calibration to the full data set determines the luminosity with a <span class="hlt">precision</span> of 1.16%. This represents the most <span class="hlt">precise</span> luminosity measurement achieved so far at a bunched-beam hadron collider.</p> <div class="credits"> <p class="dwt_author">LHCb collaboration; R. Aaij; B. Adeva; M. Adinolfi; A. Affolder; Z. Ajaltouni; S. Akar; J. Albrecht; F. Alessio; M. Alexander; S. Ali; G. Alkhazov; P. Alvarez Cartelle; A. A. Alves Jr; S. Amato; S. Amerio; Y. Amhis; L. An; L. Anderlini; J. Anderson; R. Andreassen; M. Andreotti; J. E. Andrews; R. B. Appleby; O. Aquines Gutierrez; F. Archilli; A. Artamonov; M. Artuso; E. Aslanides; G. Auriemma; M. Baalouch; S. Bachmann; J. J. Back; A. Badalov; C. Baesso; W. Baldini; R. J. Barlow; C. Barschel; S. Barsuk; W. Barter; V. Batozskaya; V. Battista; A. Bay; L. Beaucourt; J. Beddow; F. Bedeschi; I. Bediaga; S. Belogurov; K. Belous; I. Belyaev; E. Ben-Haim; G. Bencivenni; S. Benson; J. Benton; A. Berezhnoy; R. Bernet; M. -O. Bettler; M. van Beuzekom; A. Bien; S. Bifani; T. Bird; A. Bizzeti; P. M. Bjørnstad; T. Blake; F. Blanc; J. Blouw; S. Blusk; V. Bocci; A. Bondar; N. Bondar; W. Bonivento; S. Borghi; A. Borgia; M. Borsato; T. J. V. Bowcock; E. Bowen; C. Bozzi; T. Brambach; J. Bressieux; D. Brett; M. Britsch; T. Britton; J. Brodzicka; N. H. Brook; H. Brown; A. Bursche; J. Buytaert; S. Cadeddu; R. Calabrese; M. Calvi; M. Calvo Gomez; P. Campana; D. Campora Perez; A. Carbone; G. Carboni; R. Cardinale; A. Cardini; L. Carson; K. Carvalho Akiba; G. Casse; L. Cassina; L. Castillo Garcia; M. Cattaneo; Ch. Cauet; R. Cenci; M. Charles; Ph. Charpentier; M. Chefdeville; S. Chen; S. -F. Cheung; N. Chiapolini; M. Chrzaszcz; K. Ciba; X. Cid Vidal; G. Ciezarek; P. E. L. Clarke; M. Clemencic; H. V. Cliff; J. Closier; V. Coco; J. Cogan; E. Cogneras; L. Cojocariu; G. Collazuol; P. Collins; A. Comerma-Montells; A. Contu; A. Cook; M. Coombes; S. Coquereau; G. Corti; M. Corvo; I. Counts; B. Couturier; G. A. Cowan; D. C. Craik; M. Cruz Torres; S. Cunliffe; R. Currie; C. D'Ambrosio; J. Dalseno; P. David; P. N. Y. David; A. Davis; K. De Bruyn; S. De Capua; M. De Cian; J. M. De Miranda; L. De Paula; W. De Silva; P. De Simone; C. -T. Dean; D. Decamp; M. Deckenhoff; L. Del Buono; N. Déléage; D. Derkach; O. Deschamps; F. Dettori; A. Di Canto; H. Dijkstra; S. Donleavy; F. Dordei; M. Dorigo; A. Dosil Suárez; D. Dossett; A. Dovbnya; K. Dreimanis; G. Dujany; F. Dupertuis; P. Durante; R. Dzhelyadin; A. Dziurda; A. Dzyuba; S. Easo; U. Egede; V. Egorychev; S. Eidelman; S. Eisenhardt; U. Eitschberger; R. Ekelhof; L. Eklund; I. El Rifai; Ch. Elsasser; S. Ely; S. Esen; H. -M. Evans; T. Evans; A. Falabella; C. Färber; C. Farinelli; N. Farley; S. Farry; RF Fay; D. Ferguson; V. Fernandez Albor; F. Ferreira Rodrigues; M. Ferro-Luzzi; S. Filippov; M. Fiore; M. Fiorini; M. Firlej; C. Fitzpatrick; T. Fiutowski; P. Fol; M. Fontana; F. Fontanelli; R. Forty; O. Francisco; M. Frank; C. Frei; M. Frosini; J. Fu; E. Furfaro; A. Gallas Torreira; D. Galli; S. Gallorini; S. Gambetta; M. Gandelman; P. Gandini; Y. Gao; J. García Pardiñas; J. Garofoli; J. Garra Tico; L. Garrido; D. Gascon; C. Gaspar; R. Gauld; L. Gavardi; A. Geraci; E. Gersabeck; M. Gersabeck; T. Gershon; Ph. Ghez; A. Gianelle; S. Gianì; V. Gibson; L. Giubega; V. V. Gligorov; C. Göbel; D. Golubkov; A. Golutvin; A. Gomes; C. Gotti; M. Grabalosa Gándara; R. Graciani Diaz; L. A. Granado Cardoso; E. Graugés; G. Graziani; A. Grecu; E. Greening; S. Gregson; P. Griffith; L. Grillo; O. Grünberg; B. Gui; E. Gushchin; Yu. Guz; T. Gys; C. Hadjivasiliou; G. Haefeli; C. Haen; S. C. Haines; S. Hall; B. Hamilton; T. Hampson; X. Han; S. Hansmann-Menzemer; N. Harnew; S. T. Harnew; J. Harrison; J. He; T. Head; V. Heijne; K. Hennessy; P. Henrard; L. Henry; J. A. Hernando Morata; E. van Herwijnen; M. Heß; A. Hicheur; D. Hill; M. Hoballah; C. Hombach; W. Hulsbergen; P. Hunt; N. Hussain; D. Hutchcroft; D. Hynds; M. Idzik; P. Ilten; R. Jacobsson; A. Jaeger; J. Jalocha; E. Jans; P. Jaton; A. Jawahery; F. Jing; M. John; D. Johnson; C. R. Jones; C. Joram; B. Jost; N. Jurik; S. Kandybei; W. Kanso; M. Karacson; T. M. Karbach; S. Karodia; M. Kelsey; I. R. Kenyon; T. Ketel; B. Khanji; C. Khurewathanakul; S. Klaver; K. Klimaszewski; O. Kochebina; M. Kolpin; I. Komarov; R. F. Koopman; P. Koppenburg; M. Korolev; A. Kozlinskiy; L. Kravchuk; K. Kreplin; M. Kreps; G. Krocker; P. Krokovny; F. Kruse; W. Kucewicz; M. Kucharczyk; V. Kudryavtsev; K. Kurek; T. Kvaratskheliya; V. N. La Thi; D. Lacarrere; G. Lafferty; A. Lai; D. Lambert; R. W. Lambert; G. Lanfranchi; C. Langenbruch; B. Langhans; T. Latham; C. Lazzeroni; R. Le Gac; J. van Leerdam; J. -P. Lees; R. Lefèvre; A. Leflat; J. Lefrançois; S. Leo; O. Leroy; T. Lesiak; B. Leverington; Y. Li; T. Likhomanenko; M. Liles; R. Lindner; C. Linn; F. Lionetto; B. Liu; S. Lohn; I. Longstaff; J. H. Lopes; N. Lopez-March; P. Lowdon; H. Lu; D. Lucchesi; H. Luo; A. Lupato; E. Luppi; O. Lupton; F. Machefert; I. V. Machikhiliyan; F. Maciuc; O. Maev; S. Malde; A. Malinin; G. Manca; G. Mancinelli; A. Mapelli; J. Maratas; J. F. Marchand; U. Marconi; C. Marin Benito</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">302</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dspace.mit.edu/handle/1721.1/29629"> <span id="translatedtitle"><span class="hlt">Precision</span> autonomous underwater navigation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Deep-sea archaeology, an emerging application of autonomous underwater vehicle (AUV) technology, requires <span class="hlt">precise</span> navigation and guidance. As science requirements and engineering capabilities converge, navigating in the ...</p> <div class="credits"> <p class="dwt_author">Bingham, Brian S. (Brian Steven), 1973-</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">303</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008SPIE.7130E..3OP"> <span id="translatedtitle">3D measurement based on vanishing <span class="hlt">point</span> theorem</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A method of determining 3D <span class="hlt">position</span> based on vanishing-<span class="hlt">point</span> theorem in perspective picture was developed and tested. Proposed an iterative method that using fastest descent arithmetic to calculate the non-linear parameter and implemented the non-linear calibration to system. In order to get the accurate <span class="hlt">position</span> of vanishing-<span class="hlt">point</span>, a sub-pixel self-adapting recursion arithmetic was presented, that makes the originality numeric image defined in integral pixel <span class="hlt">position</span> obtain continuous mapping in rational number field. A experiment of determination 3D <span class="hlt">position</span> with a cub showed, the <span class="hlt">position</span> <span class="hlt">precision</span> can effectively improved by using the sub-pixel self-adapt recursion arithmetic in the non-linear calibration method based on vanishing-<span class="hlt">point</span>, and part of a plaster module of a person's head also been measured with this method and the vivid result of reconstruction shows the measurement can be used in free curved surface.</p> <div class="credits"> <p class="dwt_author">Pan, Shujie; Dong, Shouping; Ma, Honglian; Wang, Hongli</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">304</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://hal.inria.fr/docs/01/02/29/73/PDF/0100.pdf"> <span id="translatedtitle"><span class="hlt">PRECISE</span> VIBRATION-BASED DAMAGE LOCALIZATION IN 3D STRUCTURES CONSISTING OF 1D ELEMENTS: SINGLE VS MULTIPLE</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">and the experimental setup: The force excitation (<span class="hlt">Point</span> X) and the two vibration acceleration measurement <span class="hlt">positionsPRECISE</span> VIBRATION-BASED DAMAGE LOCALIZATION IN 3D STRUCTURES CONSISTING OF 1D ELEMENTS: SINGLE VS MULTIPLE RESPONSE MEASUREMENTS Christos S. Sakaris, John S. Sakellariou and Spilios D. Fassois Stochastic</p> <div class="credits"> <p class="dwt_author">Boyer, Edmond</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">305</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/42705135"> <span id="translatedtitle"><span class="hlt">Positive</span> Changes in Perceptions and Selections of Healthful Foods by College Students After a Short-Term <span class="hlt">Point</span>-of-Selection Intervention at a Dining Hall</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Objective: Determine the effects of a short-term, multi-faceted, <span class="hlt">point</span>-of-selection intervention on college students’ perceptions and selection of 10 targeted healthful foods in a university dining hall and changes in their self-reported overall eating behaviors. Participants: 104 college students, (age 18–23) completed pre-I and post-I surveys. Methods: Pre-survey collected at dining hall in April 2007, followed by 3-week intervention then post-survey</p> <div class="credits"> <p class="dwt_author">Sharon Peterson; Diana Poovey Duncan; Dawn Bloyd Null; Sara Long Roth; Lynn Gill</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">306</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/1708509"> <span id="translatedtitle">Measure fiber <span class="hlt">position</span> errors from spectra data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary"><span class="hlt">Precise</span> fiber <span class="hlt">positioning</span> is crucial to a wide field, multi-fiber spectroscopic survey like LAMOST. Nowadays, most <span class="hlt">position</span> error measurements are based on CCD photographic and imaging processing techniques. Those methods only work for measuring errors orthogonal to the telescope optical axis, while there also lies errors parallel to the telescope optical axis, like defocusing, and error caused by the existing deviation angle between optical axes of a fiber and the telescope. Directly measuring two latter types of <span class="hlt">position</span> errors is difficult for individual fiber, especially during observation. Possible sources of fiber <span class="hlt">position</span> errors are discussed in brief for LAMOST. By constructing a model of magnitude loss due to the fiber <span class="hlt">position</span> error for a <span class="hlt">point</span> source, we propose an indirect method to calculate the total and systematic <span class="hlt">position</span> errors for each individual fiber from spectra data. Restrictions and applications of this method are also discussed.</p> <div class="credits"> <p class="dwt_author">Chen, Jian-Jun; Luo, A-Li; Zhao, Yong-Heng</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">307</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=maintenance+AND+model+AND+applied&pg=5&id=ED285009"> <span id="translatedtitle"><span class="hlt">Precision</span> Optics Curriculum.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">This guide outlines the competency-based, two-year <span class="hlt">precision</span> optics curriculum that the American <span class="hlt">Precision</span> Optics Manufacturers Association has proposed to fill the void that it suggests will soon exist as many of the master opticians currently employed retire. The model, which closely resembles the old European apprenticeship model, calls for 300…</p> <div class="credits"> <p class="dwt_author">Reid, Robert L.; And Others</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">308</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009JASS...26...89K"> <span id="translatedtitle">Validation of GPS Based <span class="hlt">Precise</span> Orbits Using SLR Observations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this study, the YLPODS (Yonsei Laser-ranging <span class="hlt">Precision</span> Orbit Determination System) is developed for POD using SLR (Satellite Laser Ranging) NP (Normal <span class="hlt">Point</span>) observations. The performance of YLPODS is tested using SLR NP observations of TOPEX/POSEIDON and CHAMP satellite. JPL's POE (<span class="hlt">Precision</span> Orbit Ephemeris) is assumed to be true orbit, the measurement residual RMS (Root Mean Square) and the orbit accuracy (radial, along-track, cross-track) are investigated. The validation of POD using GPS (Global <span class="hlt">Positioning</span> System) raw data is achieved by YLPODS performance and highly accurate SLR NP observations. YGPODS (Yonsei GPS-based <span class="hlt">Precision</span> Orbit Determination System) is used for generating GPS based <span class="hlt">precise</span> orbits for TOPEX/POSEIDON. The initial orbit for YLPODS is derived from the YGPODS results. To validate the YGPODS results the range residual of the first adjustment of YLPODS is investigated. The YLPODS results using SLR NP observations of TOPEX/POSEIDON and CHAMP satellite show that the range residual is less than 10 cm and the orbit accuracy is about 1 m level. The validation results of the YGPODS orbits using SLR NP observations of the TOPEX/POSEIDON satellite show that the range residual is less than 10 cm. This result predicts that the accuracy of this GPS based orbits is about 1m level and it is compared with JPL's POE. Thus this result presents that the YLPODS can be used for POD validation using SLR NP observations such as STSAT-2 and KOMPSAT-5.</p> <div class="credits"> <p class="dwt_author">Kim, Young-Rok; Park, Eunseo; Park, Sang-Young; Choi, Kyu-Hong; Hwang, Yoola; Kim, Hae-Yeon; Lee, Byoung-Sun; Kim, Jaehoon</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">309</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004AGUFM.P23A0222H"> <span id="translatedtitle">Low Cost <span class="hlt">Precision</span> Lander for Lunar Exploration</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">For 60 years the US Defense Department has invested heavily in producing small, low mass, <span class="hlt">precision</span> guided vehicles. The technologies matured under these programs include terrain-aided navigation, closed loop terminal guidance algorithms, robust autopilots, high thrust-to-weight propulsion, autonomous mission management software, sensors, and data fusion. These technologies will aid NASA in addressing New Millennium Science and Technology goals as well as the requirements flowing from the Vision articulated in January 2004. Establishing and resupplying a long term lunar presence will require automated landing <span class="hlt">precision</span> not yet demonstrated. <span class="hlt">Precision</span> landing will increase safety and assure mission success. In the DOD world, such technologies are used routinely and reliably. Hence, it is timely to generate a <span class="hlt">point</span> design for a <span class="hlt">precise</span> planetary lander useful for lunar exploration. In this design science instruments amount to 10 kg, 16% of the lander vehicle mass. This compares favorably with 7% for Mars Pathfinder and less than 15% for Surveyor. The mission design flies the lander in an inert configuration to the moon, relying on a cruise stage for navigation and TCMs. The lander activates about a minute before impact. A solid booster reduces the vehicle speed to 300-450 m/s. The lander is now about 2 minutes from touchdown and has 600 to 700 m/s delta-v capability, allowing for about 10 km of vehicle divert during terminal descent. This concept of operations is chosen because it closely mimics missile operational timelines used for decades: the vehicle remains inert in a challenging environment, then must execute its mission flawlessly on a moment's notice. The vehicle design consists of a re-plumbed propulsion system, using propellant tanks and thrusters from exoatmospheric programs. A redesigned truss provides hard <span class="hlt">points</span> for landing gear, electronics, power supply, and science instruments. A radar altimeter and a Digital Scene Matching Area Correlator (DSMAC) provide data for the terminal guidance algorithms. DSMAC acquires high-resolution images for real-time correlation with a reference map. This system provides ownship <span class="hlt">position</span> with a resolution comparable to the map. Since the DSMAC can sample at 1.5 mrad, any imaging acquired below 70 km altitude will surpass the resolution available from previous missions. DSMAC has a mode where image data are compressed and downlinked. This capability could be used to downlink live images during terminal guidance. Approximately 500 kbitps telemetry would be required to provide the first live descent imaging sequence since Ranger. This would provide unique geologic context imaging for the landing site. The development path to produce such a vehicle is that used to develop missiles. First, a pathfinder vehicle is designed and built as a test bed for hardware integration including science instruments. Second, a hover test vehicle would be built. Equipped with mass mockups for the science payload, the vehicle would otherwise be an exact copy of the flight vehicle. The hover vehicle would be flown on earth to demonstrate the proper function and integration of the propulsion system, autopilots, navigation algorithms, and guidance sensors. There is sufficient delta-v in the proposed design to take off from the ground, fly a ballistic arc to over 100 m altitude, then guide to a <span class="hlt">precision</span> soft landing. Once the vehicle has flown safely on earth, then the validated design would be used to produce the flight vehicle. Since this leverages the billions of dollars DOD has invested in these technologies, it should be possible to land useful science payloads <span class="hlt">precisely</span> on the lunar surface at relatively low cost.</p> <div class="credits"> <p class="dwt_author">Head, J. N.; Gardner, T. G.; Hoppa, G. V.; Seybold, K. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">310</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/7129157"> <span id="translatedtitle"><span class="hlt">Positioning</span> apparatus</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">An apparatus is provided for <span class="hlt">precisely</span> adjusting the <span class="hlt">position</span> of an article relative to a beam emerging from a neutron source disposed in a housing. The apparatus includes a support pivotably mounted on a movable base plate and freely suspended therefrom. The support is gravity biased toward the housing and carries an article holder movable in a first direction longitudinally of the axis of said beam and normally urged into engagement against said housing. Means are provided for moving the base plate in two directions to effect movement of the suspended holder in two mutually perpendicular directions, respectively, normal to the axis of the beam.</p> <div class="credits"> <p class="dwt_author">Vogel, M.A.; Alter, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-07-07</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">311</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/53488854"> <span id="translatedtitle">Orbit determination and European station <span class="hlt">positioning</span> from satellite laser ranging</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A fundamental objective of the use of space geodetic techniques is related to the accurate spatial <span class="hlt">positioning</span> of terrestrial <span class="hlt">points</span> in a regional to global context. The results have a wide scope of applications, extending from general surveying to the monitoring of crustal movements. The most <span class="hlt">precise</span> technique for station-to-satellite relative <span class="hlt">positioning</span> involves ground-based laser ranging to artificial satellites. During</p> <div class="credits"> <p class="dwt_author">K. F. Wakker; B. A. C. Ambrosius; L. Aardoom</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">312</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20110016379&hterms=levine&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dlevine"> <span id="translatedtitle"><span class="hlt">Precision</span> Cryogenic Dilatometer</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A dilatometer based on a laser interferometer is being developed to measure mechanical creep and coefficients of thermal expansion (CTEs) of materials at temperatures ranging from ambient down to 15 K. This cryogenic dilatometer has been designed to minimize systematic errors that limit the best previously available dilatometers. At its prototype stage of development, this cryogenic dilatometer yields a strain measurement error of 35 ppb or 1.7 ppb/K CTE measurement error for a 20-K thermal load, for low-expansion materials in the temperature range from 310 down to 30 K. Planned further design refinements that include a provision for stabilization of the laser and addition of a high-<span class="hlt">precision</span> sample-holding jig are expected to reduce the measurement error to 5-ppb strain error or 0.3-ppb/K CTE error for a 20-K thermal load. The dilatometer (see figure) includes a common-path, differential, heterodyne interferometer; a dual-frequency, stabilized source bench that serves as the light source for the interferometer; a cryogenic chamber in which one places the material sample to be studied; a cryogenic system for cooling the interior of the chamber to the measurement temperature; an ultra-stable alignment stage for <span class="hlt">positioning</span> the chamber so that the sample is properly <span class="hlt">positioned</span> with respect to the interferometer; and a data-acquisition and control system. The cryogenic chamber and the interferometer portion of the dilatometer are housed in a vacuum chamber on top of a vibration isolating optical table in a cleanroom. The sample consists of two pieces a pillar on a base both made of the same material. Using reflections of the interferometer beams from the base and the top of the pillar, what is measured is the change in length of the pillar as the temperature in the chamber is changed. In their fundamental optical and electronic principles of operation, the laser light source and the interferometer are similar to those described in Common-Path Heterodyne Interferometers (NPO-20786), NASA Tech Briefs, Vol. 25, No. 7 (July 2001), page 12a, and Interferometer for Measuring Displacement to Within 20 pm (NPO- 21221), NASA Tech Briefs, Vol. 27, No. 7 (July 2003), page 8a. However, the present designs incorporate a number of special geometric, optical, and mechanical features to minimize optical and thermal-expansion effects that contribute to measurement errors. These features include the use of low-thermal expansion materials for structural components, kinematic mounting and symmetrical placement of optical components, and several measures taken to minimize spurious reflections of laser beams.</p> <div class="credits"> <p class="dwt_author">Dudik, Matthew; Halverson, Peter; Levine-West, Marie; Marcin, Martin; Peters, Robert D.; Shaklan, Stuart</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">313</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/18259361"> <span id="translatedtitle"><span class="hlt">Precision</span> blackbody sources for radiometric standards.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The <span class="hlt">precision</span> blackbody sources developed at the All-Russian Institute for Optical and Physical Measurements (Moscow, Russia) and their characteristics are analyzed. The <span class="hlt">precision</span> high-temperature graphite blackbody BB22p, large-area high-temperature pyrolytic graphite blackbody BB3200pg, middle-temperature graphite blackbody BB2000, low-temperature blackbody BB300, and gallium fixed-<span class="hlt">point</span> blackbody BB29gl and their characteristics are described. PMID:18259361</p> <div class="credits"> <p class="dwt_author">Sapritsky, V I; Khlevnoy, B B; Khromchenko, V B; Lisiansky, B E; Mekhontsev, S N; Melenevsky, U A; Morozova, S P; Prokhorov, A V; Samoilov, L N; Shapoval, V I; Sudarev, K A; Zelener, M F</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">314</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/2388389"> <span id="translatedtitle">Accelerating double <span class="hlt">precision</span> FEM simulations with GPUs</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Abstract In visualization and computer,graphics it has been shown,that the numerical solution of PDE problems can be obtained much,faster on graphics processors (GPUs) than on CPUs. However, GPUs are restricted to single <span class="hlt">precision</span> floating <span class="hlt">point</span> arithmetics which is insufficient for most technical scientific computations. Since we do not expect double <span class="hlt">precision</span> support natively in graphics hardware in the medium-term, we</p> <div class="credits"> <p class="dwt_author">R. Strzodka; S. Ture</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">315</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/quant-ph/9706032v1"> <span id="translatedtitle">Testing complete <span class="hlt">positivity</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">We study the modified dynamical evolution of the neutral kaon system under the condition of complete <span class="hlt">positivity</span>. The accuracy of the data from planned future experiments is expected to be sufficiently <span class="hlt">precise</span> to test such a hypothesis.</p> <div class="credits"> <p class="dwt_author">F. Benatti; R. Floreanini</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-06-13</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">316</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4238535"> <span id="translatedtitle">The effects of incisor inclination changes on the <span class="hlt">position</span> of <span class="hlt">point</span> A in Class II division 2 malocclusion using three-dimensional evaluation: a long-term prospective study</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Objective: The aim of this study was to evaluate change in the sagittal <span class="hlt">position</span> of <span class="hlt">point</span> A due to orthodontic treatment by orthodontic community-cone beam computed tomography (CBCT). Materials and methods: 40 subjects (22 males and 18 females) who had Class II division 2 malocclusion were recruited, and 40 subjects (23 males and 17 females) who had minor crowding in the beginning of the treatment and required no or minimal maxillary anterior tooth movement were served as control. The changes in maxillary incisor inclination, sagittal <span class="hlt">position</span> of <span class="hlt">point</span> A, SNA angle, and movement of incisor root apex and incisal edge were calculated before and after CBCT treatment. Results: Maxillary incisors were significantly proclined in the study group but not in the control group. This proclination resulted in 2.95 mm backward movement of the root apex and 6.23 mm forward movement of the incisal edge of maxillary incisors. <span class="hlt">Point</span> A moved 1.24 mm and 0.18 mm backward in the study and control groups, respectively. Incisor root apex and incisal edge almost remained stable in the control group. No significant change was observed in the SNA angle in both the study and control groups. However, the change in SNA between the two groups was found to be significant. Conclusions: Proclination of maxillary incisors with backward movement of incisor root apex caused posterior movement of <span class="hlt">point</span> A. This posterior movement significantly affects the SNA angle.</p> <div class="credits"> <p class="dwt_author">Chen, Qiushuo; Zhang, Caixia; Zhou, Yu</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">317</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3658722"> <span id="translatedtitle">Experimental Study on the <span class="hlt">Precise</span> Orbit Determination of the BeiDou Navigation Satellite System</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">The regional service of the Chinese BeiDou satellite navigation system is now in operation with a constellation including five Geostationary Earth Orbit satellites (GEO), five Inclined Geosynchronous Orbit (IGSO) satellites and four Medium Earth Orbit (MEO) satellites. Besides the standard <span class="hlt">positioning</span> service with <span class="hlt">positioning</span> accuracy of about 10 m, both <span class="hlt">precise</span> relative <span class="hlt">positioning</span> and <span class="hlt">precise</span> <span class="hlt">point</span> <span class="hlt">positioning</span> are already demonstrated. As is well known, <span class="hlt">precise</span> orbit and clock determination is essential in enhancing <span class="hlt">precise</span> <span class="hlt">positioning</span> services. To improve the satellite orbits of the BeiDou regional system, we concentrate on the impact of the tracking geometry and the involvement of MEOs, and on the effect of integer ambiguity resolution as well. About seven weeks of data collected at the BeiDou Experimental Test Service (BETS) network is employed in this experimental study. Several tracking scenarios are defined, various processing schemata are designed and carried out; and then, the estimates are compared and analyzed in detail. The results show that GEO orbits, especially the along-track component, can be significantly improved by extending the tracking network in China along longitude direction, whereas IGSOs gain more improvement if the tracking network extends in latitude. The involvement of MEOs and ambiguity-fixing also make the orbits better. PMID:23529116</p> <div class="credits"> <p class="dwt_author">He, Lina; Ge, Maorong; Wang, Jiexian; Wickert, Jens; Schuh, Harald</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">318</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23529116"> <span id="translatedtitle">Experimental study on the <span class="hlt">precise</span> orbit determination of the BeiDou navigation satellite system.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The regional service of the Chinese BeiDou satellite navigation system is now in operation with a constellation including five Geostationary Earth Orbit satellites (GEO), five Inclined Geosynchronous Orbit (IGSO) satellites and four Medium Earth Orbit (MEO) satellites. Besides the standard <span class="hlt">positioning</span> service with <span class="hlt">positioning</span> accuracy of about 10 m, both <span class="hlt">precise</span> relative <span class="hlt">positioning</span> and <span class="hlt">precise</span> <span class="hlt">point</span> <span class="hlt">positioning</span> are already demonstrated. As is well known, <span class="hlt">precise</span> orbit and clock determination is essential in enhancing <span class="hlt">precise</span> <span class="hlt">positioning</span> services. To improve the satellite orbits of the BeiDou regional system, we concentrate on the impact of the tracking geometry and the involvement of MEOs, and on the effect of integer ambiguity resolution as well. About seven weeks of data collected at the BeiDou Experimental Test Service (BETS) network is employed in this experimental study. Several tracking scenarios are defined, various processing schemata are designed and carried out; and then, the estimates are compared and analyzed in detail. The results show that GEO orbits, especially the along-track component, can be significantly improved by extending the tracking network in China along longitude direction, whereas IGSOs gain more improvement if the tracking network extends in latitude. The involvement of MEOs and ambiguity-fixing also make the orbits better. PMID:23529116</p> <div class="credits"> <p class="dwt_author">He, Lina; Ge, Maorong; Wang, Jiexian; Wickert, Jens; Schuh, Harald</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">319</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/18262216"> <span id="translatedtitle"><span class="hlt">Precision</span> and consistency of contour interpolation.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We investigated conditions under which observers can interpolate occluded contours by a single, stable, smooth contour. Observers viewed partly-occluded contours defined by linear segments and estimated the <span class="hlt">position</span> and tangent orientation of the contour at multiple locations within the occluded region. We measured the <span class="hlt">precision</span> and consistency of observers' settings as indices of successful interpolation. We found that although increasing the relative offset between inducers led to a decrease in both <span class="hlt">precision</span> and consistency, increasing turning angle affected primarily <span class="hlt">precision</span>. We discuss conditions under which interpolation settings are consistent with a single, stable smooth contour. PMID:18262216</p> <div class="credits"> <p class="dwt_author">Fulvio, Jacqueline M; Singh, Manish; Maloney, Laurence T</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">320</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4227133"> <span id="translatedtitle">A Cyclin T1 <span class="hlt">point</span> mutation that abolishes <span class="hlt">positive</span> transcription elongation factor (P-TEFb) binding to Hexim1 and HIV tat</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Background The <span class="hlt">positive</span> transcription elongation factor b (P-TEFb) plays an essential role in activating HIV genome transcription. It is recruited to the HIV LTR promoter through an interaction between the Tat viral protein and its Cyclin T1 subunit. P-TEFb activity is inhibited by direct binding of its subunit Cyclin T (1 or 2) with Hexim (1 or 2), a cellular protein, bound to the 7SK small nuclear RNA. Hexim1 competes with Tat for P-TEFb binding. Results Mutations that impair human Cyclin T1/Hexim1 interaction were searched using systematic mutagenesis of these proteins coupled with a yeast two-hybrid screen for loss of protein interaction. Evolutionary conserved Hexim1 residues belonging to an unstructured peptide located N-terminal of the dimerization domain, were found to be critical for P-TEFb binding. Random mutagenesis of the N-terminal region of Cyclin T1 provided identification of single amino-acid mutations that impair Hexim1 binding in human cells. Furthermore, conservation of critical residues supported the existence of a functional Hexim1 homologue in nematodes. Conclusions Single Cyclin T1 amino-acid mutations that impair Hexim1 binding are located on a groove between the two cyclin folds and define a surface overlapping the HIV-1 Tat protein binding surface. One residue, Y175, in the centre of this groove was identified as essential for both Hexim1 and Tat binding to P-TEFb as well as for HIV transcription. PMID:24985203</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_15");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' 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src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">321</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1998SPIE.3365...22H"> <span id="translatedtitle">Acquisition, tracking, and <span class="hlt">pointing</span> system for self-protection applications</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A state-of-the-art acquisition/tracking/<span class="hlt">positioning</span> (ATP) system for vehicle protection and area defense application is presently being developed. The ATP system, referred to as the high performance laser fire control system, has been designed to automatically acquire, track, rangefind and designate top attack weapons, such as mortars and artillery, as well as line-of-sight type weapons, such as anti-tank guided missiles and anti-tank projectiles. The ATP mission scenario requires full hemispherical coverage, extremely high acceleration capabilities, <span class="hlt">precision</span> stabilization, and <span class="hlt">precision</span> <span class="hlt">pointing</span>.</p> <div class="credits"> <p class="dwt_author">Hammer, Steven J.; Stockum, Larry A.; Chesser, Douglas E.; Miller, John E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">322</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3970034"> <span id="translatedtitle">Developing <span class="hlt">Precision</span> Stroke Imaging</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Stroke experts stand at the cusp of a unique opportunity to advance the care of patients with cerebrovascular disorders across the globe through improved imaging approaches. NIH initiatives including the Stroke Progress Review Group promotion of imaging in stroke research and the newly established NINDS Stroke Trials network converge with the rapidly evolving concept of <span class="hlt">precision</span> medicine. <span class="hlt">Precision</span> stroke imaging portends the coming shift to individualized approaches to cerebrovascular disorders where big data may be leveraged to identify and manage stroke risk with specific treatments utilizing an improved neuroimaging infrastructure, data collection, and analysis. We outline key aspects of the stroke imaging field where <span class="hlt">precision</span> medicine may rapidly transform the care of stroke patients in the next few years. PMID:24715885</p> <div class="credits"> <p class="dwt_author">Feldmann, Edward; Liebeskind, David S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">323</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24715885"> <span id="translatedtitle">Developing <span class="hlt">precision</span> stroke imaging.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Stroke experts stand at the cusp of a unique opportunity to advance the care of patients with cerebrovascular disorders across the globe through improved imaging approaches. NIH initiatives including the Stroke Progress Review Group promotion of imaging in stroke research and the newly established NINDS Stroke Trials network converge with the rapidly evolving concept of <span class="hlt">precision</span> medicine. <span class="hlt">Precision</span> stroke imaging portends the coming shift to individualized approaches to cerebrovascular disorders where big data may be leveraged to identify and manage stroke risk with specific treatments utilizing an improved neuroimaging infrastructure, data collection, and analysis. We outline key aspects of the stroke imaging field where <span class="hlt">precision</span> medicine may rapidly transform the care of stroke patients in the next few years. PMID:24715885</p> <div class="credits"> <p class="dwt_author">Feldmann, Edward; Liebeskind, David S</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">324</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/1108400"> <span id="translatedtitle"><span class="hlt">Precision</span> electron polarimetry</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A new generation of <span class="hlt">precise</span> Parity-Violating experiments will require a sub-percent accuracy of electron beam polarimetry. Compton polarimetry can provide such accuracy at high energies, but at a few hundred MeV the small analyzing power limits the sensitivity. M{\\o}ller polarimetry provides a high analyzing power independent on the beam energy, but is limited by the properties of the polarized targets commonly used. Options for <span class="hlt">precision</span> polarimetry at ~300 MeV will be discussed, in particular a proposal to use ultra-cold atomic hydrogen traps to provide a 100\\%-polarized electron target for M{\\o}ller polarimetry.</p> <div class="credits"> <p class="dwt_author">Chudakov, Eugene A. [JLAB</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">325</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850000518&hterms=GOODWIN&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DGOODWIN"> <span id="translatedtitle">Hydraulic Cylinder With an Integral <span class="hlt">Position</span> Indicator</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Linear variable differential transformer (LVDT) incorporated within cylinder of hydraulic actuator gives <span class="hlt">precise</span> readout of <span class="hlt">position</span> of piston relative to cylinder. LVDT contained completely within actuator. System requires <span class="hlt">precise</span> <span class="hlt">positioning</span> and <span class="hlt">position</span> readout for computer control of model motions. Minimal space available for motion cylinders, and <span class="hlt">precise</span>, continuous <span class="hlt">position</span> readout (with no steps or pulses) required. Device provides continuous and accurate <span class="hlt">position</span> indication of a hydraulic cylinder by means of integral, coaxially mounted LVDT.</p> <div class="credits"> <p class="dwt_author">Goodwin, G. O.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">326</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/564417"> <span id="translatedtitle">Profile Guided Code <span class="hlt">Positioning</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper presents the results of our investigation of code <span class="hlt">positioning</span> techniques using execution profile data as input into the compilation process. The primary objective of the <span class="hlt">positioning</span> is to reduce the overhead of the instruction memory hierarchy. After initial investigation in the literature, we decided to implement two prototypes for the Hewlett-Packard <span class="hlt">Precision</span> Architecture (PA-RISC). The first, built on</p> <div class="credits"> <p class="dwt_author">Karl Pettis; Robert C. Hansen</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">327</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014NDS...119..383L"> <span id="translatedtitle">Targets for <span class="hlt">Precision</span> Measurements</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The general properties needed in targets (sources) for high <span class="hlt">precision</span>, high accuracy measurements are reviewed. The application of these principles to the problem of developing targets for the Fission TPC is described. Longer term issues, such as the availability of actinide materials, improved knowledge of energy losses and straggling and the stability of targets during irradiation are also discussed.</p> <div class="credits"> <p class="dwt_author">Loveland, W.; Yao, L.; Asner, D. M.; Baker, R. G.; Bundgaard, J.; Burgett, E.; Cunningham, M.; Deaven, J.; Duke, D. L.; Greife, U.; Grimes, S.; Heffner, M.; Hill, T.; Isenhower, D.; Klay, J. L.; Kleinrath, V.; Kornilov, N.; Laptev, A. B.; Massey, T. N.; Meharchand, R.; Qu, H.; Ruz, J.; Sangiorgio, S.; Selhan, B.; Snyder, L.; Stave, S.; Tatishvili, G.; Thornton, R. T.; Tovesson, F.; Towell, D.; Towell, R. S.; Watson, S.; Wendt, B.; Wood, L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">328</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://vis.pnnl.gov/pdf/fliers/PIE.pdf"> <span id="translatedtitle"><span class="hlt">Precision</span> Information Environments</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">and tailored around specific Emergency Management needs for data aggregation and communication Ingests large of the current status of events, activities, tasks, and communications and presenting it to an emergency response Laboratory are developing future work environments for the emergency management community. These <span class="hlt">Precision</span></p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">329</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/906192"> <span id="translatedtitle"><span class="hlt">Precise</span> Service Level Agreements</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">SLAng is an XML language for defining service levelagreements, the part of a contract between the client andprovider of an Internet service that describes the quality attributesthat the service is required to possess. We definethe semantics of SLAng <span class="hlt">precisely</span> by modelling the syntax ofthe language in UML, then relating the language model toa model that describes the structure and behaviour</p> <div class="credits"> <p class="dwt_author">James Skene; D. Davide Lamanna; Wolfgang Emmerich</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">330</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/7254681"> <span id="translatedtitle"><span class="hlt">Precision</span> liquid level sensor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A <span class="hlt">precision</span> liquid level sensor utilizes a balanced R. F. bridge, each arm including an air dielectric line. Changes in liquid level along one air dielectric line imbalance the bridge and create a voltage which is directly measurable across the bridge. 2 figs.</p> <div class="credits"> <p class="dwt_author">Field, M.E.; Sullivan, W.H.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-29</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">331</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/astro-ph/0505455v1"> <span id="translatedtitle">Stellar Photometry and Astrometry with Discrete <span class="hlt">Point</span> Spread Functions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">The key features of the MATPHOT algorithm for <span class="hlt">precise</span> and accurate stellar photometry and astrometry using discrete <span class="hlt">Point</span> Spread Functions are described. A discrete <span class="hlt">Point</span> Spread Function (PSF) is a sampled version of a continuous PSF which describes the two-dimensional probability distribution of photons from a <span class="hlt">point</span> source (star) just above the detector. The shape information about the photon scattering pattern of a discrete PSF is typically encoded using a numerical table (matrix) or a FITS image file. Discrete PSFs are shifted within an observational model using a 21-pixel-wide damped sinc function and <span class="hlt">position</span> partial derivatives are computed using a five-<span class="hlt">point</span> numerical differentiation formula. <span class="hlt">Precise</span> and accurate stellar photometry and astrometry is achieved with undersampled CCD observations by using supersampled discrete PSFs that are sampled 2, 3, or more times more finely than the observational data. The <span class="hlt">precision</span> and accuracy of the MATPHOT algorithm is demonstrated by using the C-language MPD code to analyze simulated CCD stellar observations; measured performance is compared with a theoretical performance model. Detailed analysis of simulated Next Generation Space Telescope observations demonstrate that millipixel relative astrometry and millimag photometric <span class="hlt">precision</span> is achievable with complicated space-based discrete PSFs. For further information about MATPHOT and MPD, including source code and documentation, see http://www.noao.edu/staff/mighell/matphot</p> <div class="credits"> <p class="dwt_author">Kenneth J. Mighell</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-05-20</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">332</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/1750487"> <span id="translatedtitle">A Technique for Extracting Highly <span class="hlt">Precise</span> Photometry for the Two-Wheeled Kepler Mission</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">The original Kepler mission achieved high photometric <span class="hlt">precision</span> thanks to ultra-stable <span class="hlt">pointing</span> enabled by use of four reaction wheels. The loss of two of these reaction wheels reduced the telescope's ability to <span class="hlt">point</span> <span class="hlt">precisely</span> for extended periods of time, and as a result, the photometric <span class="hlt">precision</span> has suffered. We present a technique for generating photometric light curves from pixel-level data obtained with the two-wheeled extended Kepler mission, K2. Our photometric technique accounts for the non-uniform pixel response function of the Kepler detectors by correlating flux measurements with the spacecraft's <span class="hlt">pointing</span> and removing the dependence. When we apply our technique to the ensemble of stars observed during the Kepler Two-Wheel Concept Engineering Test, we find improvements over raw K2 photometry by factors of 2-5, with noise properties qualitatively similar to Kepler targets at the same magnitudes. We find evidence that the improvement in photometric <span class="hlt">precision</span> depends on each target's <span class="hlt">position</span> in the ...</p> <div class="credits"> <p class="dwt_author">Vanderburg, Andrew</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">333</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3793553"> <span id="translatedtitle">A cephalometric study to ascertain the use of nasion as a guide in locating the <span class="hlt">position</span> of orbitale as an anterior reference <span class="hlt">point</span> among a population of South Coastal Karnataka</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Context: To ascertain the use of nasion as a guide in locating the <span class="hlt">position</span> of orbitale as an anterior reference <span class="hlt">point</span> in the face-bow transfer records in individuals having different facial types. Aims: This study evaluated the distance from the nasion to the orbitale using cephalometric measurements to ascertain the use of nasion as a guide in locating the <span class="hlt">position</span> of orbitale as an anterior reference <span class="hlt">point</span> in individuals having different facial types among a population of South Coastal Karnataka. Subjects and Methods: Anthropometric measurements were made on 61 subjects and they were classified into mesoprosopic, euryprosopic and leptoprosopic facial type groups based upon the prosopic index. Lateral cephalometric radiographs were taken and nasion to orbitale distance was measured. The collected data was tabulated and statistically analyzed. Statistical Analysis Used: The statistical test carried out was the analysis of variance test and correlations were checked for using Pearson's correlation test. Results: The study found the mean distance from nasion to orbitale was 24.25 mm with a standard deviation 4.26 mm. A good correlation was found between prosopic index and nasion to orbitale distance. No statistically significant variation in nasion to orbitale distance in individuals of different facial types was found. Conclusions: Although, variation exists it was not statistically significant. However, since a large range of measurements were found, prior evaluation using cephalometric radiographs may be necessary in certain individuals. PMID:24124298</p> <div class="credits"> <p class="dwt_author">Hegde, Chethan; Lobo, Nikhil J.; Prasad, Krishna D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">334</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.isg.rhul.ac.uk/~alex/papers/designs01.pdf"> <span id="translatedtitle"><span class="hlt">Point</span>-weight designs with design conditions on t <span class="hlt">points</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary"><span class="hlt">Point</span>-weight designs with design conditions on t <span class="hlt">points</span> Alexander W. Dent Mathematics Dept., Royal examines some of the properties of <span class="hlt">point</span>-weight incidence structures, i.e. incidence structures for which every <span class="hlt">point</span> is assigned a <span class="hlt">positive</span> integer weight. In particular it examines <span class="hlt">point</span>-weight designs</p> <div class="credits"> <p class="dwt_author">Dent, Alexander W.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">335</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.americanprecision.org/index.php"> <span id="translatedtitle">American <span class="hlt">Precision</span> Museum</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Housed in the historic Robbins & Lawrence Armory in Windsor, Vermont, the American <span class="hlt">Precision</span> Museum "celebrates the ingenuity of our mechanical forebears, and explores the effects of their work on everyday lives." Interestingly enough, some of the tools and methods that made mass production possible were developed at this very armory, and the concept of <span class="hlt">precision</span> manufacturing provides "the foundation for modern industry around the world." First-time visitors should start by viewing the 8.5-minute introductory film on the homepage, as it provides a good overview of the museum. Next, visitors should look over the "Machine Tool Hall of Fame" area. Here they can learn about various inductees, including Frank Lyman Cone, Edward P. Bullard, and William L. Bryant, who developed the technology that made the rapid production of bearing races possible. The site is rounded out by information about visiting the museum, along with a link to their mailing list.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">336</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/sciencecinema/biblio/1025921"> <span id="translatedtitle">A passion for <span class="hlt">precision</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/sciencecinema/">ScienceCinema</a></p> <p class="result-summary">For more than three decades, the quest for ever higher <span class="hlt">precision</span> in laser spectroscopy of the simple hydrogen atom has inspired many advances in laser, optical, and spectroscopic techniques, culminating in femtosecond laser optical frequency combs  as perhaps the most <span class="hlt">precise</span> measuring tools known to man. Applications range from optical atomic clocks and tests of QED and relativity to searches for time variations of fundamental constants. Recent experiments are extending frequency comb techniques into the extreme ultraviolet. Laser frequency combs can also control the electric field of ultrashort light pulses, creating powerful new tools for the emerging field of attosecond science.Organiser(s): L. Alvarez-Gaume / PH-THNote: * Tea & coffee will be served at 16:00.</p> <div class="credits"> <p class="dwt_author">None</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-10-06</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">337</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.cs.colorado.edu/~srirams/papers/floatPtPaper09.pdf"> <span id="translatedtitle">Software Model Checking the <span class="hlt">Precision</span> of Floating-<span class="hlt">Point</span> Programs</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">of real- time and embedded software such as used in medical devices, cars, airplanes and so on, Sriram Sankaranarayanan, and Aarti Gupta NEC Laboratories America 4 Independence Way, Suite 200 to computational nu- meric instabilities. In this work, we target numerical programs implemented using the IEEE 754</p> <div class="credits"> <p class="dwt_author">Sankaranarayanan, Sriram</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">338</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/urc/sites/unh.edu.urc/files/media/pdfs2011/award_pdfs/2009/M%20O'Neil%20URC09start.pdf"> <span id="translatedtitle"><span class="hlt">Precision</span> <span class="hlt">Pointing</span> in the Sky for IBEX Interstellar Flow Observations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">.4 crescent quarter gibbous full AngularPeakSeparation(indegrees) Moon Phase Angular Peak Separation Varies With Moon Phase Moon Simulation Program & Results The moon is much brighter than other objects in the sky so difference between 1st and 3rd quarter phases. · The dark mare on the moon's surface alter the star sensor</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">339</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19740024170&hterms=precision+pointing&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dprecision%2Bpointing"> <span id="translatedtitle">Attitude control concepts for <span class="hlt">precision-pointing</span> nonrigid spacecraft</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Literal criteria are developed for the controllability and observability of general models of flexible spacecraft. Results are interpreted in special cases and in physical terms, permitting in some cases the identification of uncontrollable and unobservable states simply by examination of scalars composed of modal parameters and location matrices for sensors and actuators. A procedure is established for isolation of uncontrollable states, whereby sensor and actuator configurations assure that uncontrollable flexible mode states are also unobservable; in many applications such states can then be removed by coordinate truncation.</p> <div class="credits"> <p class="dwt_author">Likins, P. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">1974-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">340</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/27295618"> <span id="translatedtitle">Estimating <span class="hlt">Precision</span> Using Duplicate Measurements</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Precision</span> is a concept for which there is no universally accepted metric. Reports of <span class="hlt">precision</span> vary depending on the formula and inclusion criteria used to calculate them. To properly interpret and utilize reported <span class="hlt">precisions</span>, the user must understand exactly what the <span class="hlt">precision</span> represents. This paper uses duplicate Interagency Monitoring of Protected Visual Environments (IMPROVE) measurements to illustrate distinctions among different</p> <div class="credits"> <p class="dwt_author">Nicole Pauly Hyslop; Warren H. White; Warren White; Krystyna Trzepla-Nabaglo; Paul Wakabayashi; Charles McDade; Ann Dillner; Hege Indresand; William Malm; Gavin McMeeking; Sonia Kreidenweis; Ezra Levin; Christian Carrico; Derek Day; Jeffrey Collett; Taehyoung Lee; Amy Sullivan; Suresh Raja; Marc Pitchford; Richard Poirot; Bret Schichtel; Patricia Brewer; Tom Moore; Mark Green; Shobha Kondragunta; Pubu Ciren; Chuanyu Xu; Delbert Eatough; Robert Farber; Marco Rodriguez; Michael Barna</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" 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onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_19");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">341</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19720021818&hterms=snells+law&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dsnells%2Blaw"> <span id="translatedtitle"><span class="hlt">Precise</span> linear sun sensor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">An evaluation of the <span class="hlt">precise</span> linear sun sensor relating to future mission applications was performed. The test procedures, data, and results of the dual-axis, solid-state system are included. Brief descriptions of the sensing head and of the system's operational characteristics are presented. A unique feature of the system is that multiple sensor heads with various fields of view may be used with the same electronics.</p> <div class="credits"> <p class="dwt_author">Johnston, D. D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1972-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">342</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60185408"> <span id="translatedtitle"><span class="hlt">Precision</span> guided parachute LDRD final report</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This report summarizes the results of the <span class="hlt">Precision</span> Guided Parachute LDRD, a two year program at Sandia National Laboratories which developed a Global <span class="hlt">Positioning</span> System (GPS) guided parachute capable of autonomous flight and landings. A detailed computer model of a gliding parachute was developed for software only simulations. A hardware in-the-loop simulator was developed and used for flight package system</p> <div class="credits"> <p class="dwt_author">Gilkey</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">343</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/49980748"> <span id="translatedtitle">Testing the <span class="hlt">precision</span> lightweight GPS receiver</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Innovative field testing techniques are employed at Holloman Air Force Base to help the Global <span class="hlt">Positioning</span> System (GPS) NAVSTAR Joint Program Office (JPO) test the <span class="hlt">precision</span> lightweight GPS receiver (PLGR). Characterizing the PLGR's accuracy in dynamic environments is of prime importance, but testing also prescribes the evaluation of its ability to receive differential GPS corrections, real time, and its electronic</p> <div class="credits"> <p class="dwt_author">Barbara Cosentino</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">344</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/1544026"> <span id="translatedtitle">Testing the <span class="hlt">precision</span> lightweight GPS receiver</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Innovative field testing techniques are employed at Holloman Air Force Base to help the Global <span class="hlt">Positioning</span> System (GPS) NAVSTAR Joint Program Office (JPO) test the <span class="hlt">Precision</span> Lightweight GPS Receiver (PLGR). Characterizing the PLGR's accuracy in dynamic environments is of prime importance but testing also prescribes the evaluation of its ability to receive differential GPS corrections, real time, and its Electronic</p> <div class="credits"> <p class="dwt_author">Barbara Cosentino</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">345</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/2203107"> <span id="translatedtitle">Humancentric Applications of <span class="hlt">Precise</span> Location Based Services</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper focuses on the growing need to consider the implications of humancentric applications of <span class="hlt">precise</span> location based services (LBS). As newer <span class="hlt">positioning</span> technologies are introduced into the market with a greater level of location accuracy, and existing technologies are utilized in an integrated fashion to overcome limitations, issues pertaining to the use and potential misuse of location information rise</p> <div class="credits"> <p class="dwt_author">Laura Perusco; Katina Michael</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">346</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ushrl.saa.ars.usda.gov/sp2userfiles/place/66570000/manuscripts/2005/man730.pdf"> <span id="translatedtitle">Opportunities for conservation with <span class="hlt">precision</span> irrigation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Precision</span> agriculture has mostly emphasized variable-rate nutrients, seeding, and pesticide application, but at several research sites, variable-rate irrigation equipment has been developed to explore the potential for managing irrigation spatially. The modifications to commercial machines are relatively straightforward, but costly; thus economic analyses have not been <span class="hlt">positive</span> at current grain price: water cost ratios. However, with increased attention to conservation</p> <div class="credits"> <p class="dwt_author">E. J. Sadler; R. G. Evans; K. C. Stone; C. R. Camp</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">347</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.colorado.edu/geography/gcraft/notes/gps/gps_f.html"> <span id="translatedtitle">The Global <span class="hlt">Positioning</span> System</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This site presents information about the Global <span class="hlt">Positioning</span> System (GPS), including basic information, images, and plentiful in-depth technical information about GPS. Topics covered include U.S. Department of Defense Satellite Navigation System, GPS <span class="hlt">Positioning</span> Services Specified in the Federal Radionavigation Plan, GPS Satellite Signals, GPS Data, <span class="hlt">Position</span> and Time from GPS, GPS Error Sources, Geometric Dilution of <span class="hlt">Precision</span>, and Differential GPS Techniques. There is a list of related documents and a reference list.</p> <div class="credits"> <p class="dwt_author">Foote, Kenneth; Dana, Peter</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">348</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/26350860"> <span id="translatedtitle">Single setup estimation of a five-axis machine tool eight link errors by programmed end <span class="hlt">point</span> constraint and on the fly measurement with Capball sensor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Five-axis machine tools can be programmed to keep a constant nominal tool end <span class="hlt">point</span> <span class="hlt">position</span> while exercising all five axes simultaneously. This kinematic capability allows the use of a 3D proximity sensing head mounted at the spindle to track the <span class="hlt">position</span> changes of a <span class="hlt">precision</span> steel ball mounted on the machine table effectively measuring the 3D Cartesian volumetric errors of</p> <div class="credits"> <p class="dwt_author">S. H. H. Zargarbashi; J. R. R. Mayer</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">349</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/672695"> <span id="translatedtitle">High <span class="hlt">precision</span> redundant robotic manipulator</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A high <span class="hlt">precision</span> redundant robotic manipulator for overcoming contents imposed by obstacles or imposed by a highly congested work space is disclosed. One embodiment of the manipulator has four degrees of freedom and another embodiment has seven degrees of freedom. Each of the embodiments utilize a first selective compliant assembly robot arm (SCARA) configuration to provide high stiffness in the vertical plane, a second SCARA configuration to provide high stiffness in the horizontal plane. The seven degree of freedom embodiment also utilizes kinematic redundancy to provide the capability of avoiding obstacles that lie between the base of the manipulator and the end effector or link of the manipulator. These additional three degrees of freedom are added at the wrist link of the manipulator to provide pitch, yaw and roll. The seven degrees of freedom embodiment uses one revolute <span class="hlt">point</span> per degree of freedom. For each of the revolute joints, a harmonic gear coupled to an electric motor is introduced, and together with properly designed based servo controllers provide an end <span class="hlt">point</span> repeatability of less than 10 microns. 3 figs.</p> <div class="credits"> <p class="dwt_author">Young, K.K.D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-09-22</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">350</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/871860"> <span id="translatedtitle">High <span class="hlt">precision</span> redundant robotic manipulator</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A high <span class="hlt">precision</span> redundant robotic manipulator for overcoming contents imposed by obstacles or imposed by a highly congested work space. One embodiment of the manipulator has four degrees of freedom and another embodiment has seven degreed of freedom. Each of the embodiments utilize a first selective compliant assembly robot arm (SCARA) configuration to provide high stiffness in the vertical plane, a second SCARA configuration to provide high stiffness in the horizontal plane. The seven degree of freedom embodiment also utilizes kinematic redundancy to provide the capability of avoiding obstacles that lie between the base of the manipulator and the end effector or link of the manipulator. These additional three degrees of freedom are added at the wrist link of the manipulator to provide pitch, yaw and roll. The seven degrees of freedom embodiment uses one revolute <span class="hlt">point</span> per degree of freedom. For each of the revolute joints, a harmonic gear coupled to an electric motor is introduced, and together with properly designed based servo controllers provide an end <span class="hlt">point</span> repeatability of less than 10 microns.</p> <div class="credits"> <p class="dwt_author">Young, Kar-Keung David (Mountain View, CA)</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">351</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/sciencecinema/biblio/987972"> <span id="translatedtitle"><span class="hlt">Precision</span> Robotic Assembly Machine</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/sciencecinema/">ScienceCinema</a></p> <p class="result-summary">The world's largest laser system is the National Ignition Facility (NIF), located at Lawrence Livermore National Laboratory. NIF's 192 laser beams are amplified to extremely high energy, and then focused onto a tiny target about the size of a BB, containing frozen hydrogen gas. The target must be perfectly machined to incredibly demanding specifications. The Laboratory's scientists and engineers have developed a device called the "<span class="hlt">Precision</span> Robotic Assembly Machine" for this purpose. Its unique design won a prestigious R&D-100 award from R&D Magazine.</p> <div class="credits"> <p class="dwt_author">None</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">352</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/987972"> <span id="translatedtitle"><span class="hlt">Precision</span> Robotic Assembly Machine</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The world's largest laser system is the National Ignition Facility (NIF), located at Lawrence Livermore National Laboratory. NIF's 192 laser beams are amplified to extremely high energy, and then focused onto a tiny target about the size of a BB, containing frozen hydrogen gas. The target must be perfectly machined to incredibly demanding specifications. The Laboratory's scientists and engineers have developed a device called the "<span class="hlt">Precision</span> Robotic Assembly Machine" for this purpose. Its unique design won a prestigious R&D-100 award from R&D Magazine.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2009-08-14</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">353</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/435056"> <span id="translatedtitle"><span class="hlt">Precision</span> electroweak measurements</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Recent electroweak <span class="hlt">precision</span> measurements fro {ital e}{sup +}{ital e}{sup -} and {ital p{anti p}} colliders are presented. Some emphasis is placed on the recent developments in the heavy flavor sector. The measurements are compared to predictions from the Standard Model of electroweak interactions. All results are found to be consistent with the Standard Model. The indirect constraint on the top quark mass from all measurements is in excellent agreement with the direct {ital m{sub t}} measurements. Using the world`s electroweak data in conjunction with the current measurement of the top quark mass, the constraints on the Higgs` mass are discussed.</p> <div class="credits"> <p class="dwt_author">Demarteau, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">354</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/871575"> <span id="translatedtitle"><span class="hlt">Precision</span> flyer initiator</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A <span class="hlt">precision</span> flyer initiator forms a substantially spherical detonation wave in a high explosive (HE) pellet. An explosive driver, such as a detonating cord, a wire bridge circuit or a small explosive, is detonated. A flyer material is sandwiched between the explosive driver and an end of a barrel that contains an inner channel. A projectile or "flyer" is sheared from the flyer material by the force of the explosive driver and projected through the inner channel. The flyer than strikes the HE pellet, which is supported above a second end of the barrel by a spacer ring. A gap or shock decoupling material delays the shock wave in the barrel from predetonating the HE pellet before the flyer. A spherical detonation wave is formed in the HE pellet. Thus, a shock wave traveling through the barrel fails to reach the HE pellet before the flyer strikes the HE pellet. The <span class="hlt">precision</span> flyer initiator can be used in mining devices, well-drilling devices and anti-tank devices.</p> <div class="credits"> <p class="dwt_author">Frank, Alan M. (Livermore, CA); Lee, Ronald S. (Livermore, CA)</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">355</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/644399"> <span id="translatedtitle"><span class="hlt">Precision</span> flyer initiator</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">A <span class="hlt">precision</span> flyer initiator forms a substantially spherical detonation wave in a high explosive (HE) pellet. An explosive driver, such as a detonating cord, a wire bridge circuit or a small explosive, is detonated. A flyer material is sandwiched between the explosive driver and an end of a barrel that contains an inner channel. A projectile or ``flyer`` is sheared from the flyer material by the force of the explosive driver and projected through the inner channel. The flyer than strikes the HE pellet, which is supported above a second end of the barrel by a spacer ring. A gap or shock decoupling material delays the shock wave in the barrel from predetonating the HE pellet before the flyer. A spherical detonation wave is formed in the HE pellet. Thus, a shock wave traveling through the barrel fails to reach the HE pellet before the flyer strikes the HE pellet. The <span class="hlt">precision</span> flyer initiator can be used in mining devices, well-drilling devices and anti-tank devices. 10 figs.</p> <div class="credits"> <p class="dwt_author">Frank, A.M.; Lee, R.S.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-05-26</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">356</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dspace.mit.edu/handle/1721.1/29901"> <span id="translatedtitle">Multivariable isoperformance methodology for <span class="hlt">precision</span> opto-mechanical systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary"><span class="hlt">Precision</span> opto-mechanical systems, such as space telescopes, combine structures, optics and controls in order to meet stringent <span class="hlt">pointing</span> and phasing requirements. In this context a novel approach to the design of complex, ...</p> <div class="credits"> <p class="dwt_author">De Weck, Olivier Ladislas, 1968-</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">357</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.seattleu.edu/uploadedFiles/COE/Announcements/MIT%20instructor%20position%20updated.pdf"> <span id="translatedtitle"><span class="hlt">Position</span> Information <span class="hlt">Position</span> Details</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">policies, admission policies, scholarship and loan programs, athletics, and other school_10398 Department College of Education - Masters in Teaching Program Pay Band Faculty FLSA Status Exempt The College of Education invites applications for a 1-year, full time non-tenure track Instructor <span class="hlt">position</span> w</p> <div class="credits"> <p class="dwt_author">Carter, John</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">358</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://biochem.stanford.edu/spudich/PDFs/AllPubs/174_2007_PLOS.Biol_Altman_Goswami_etal.pdf"> <span id="translatedtitle"><span class="hlt">Precise</span> <span class="hlt">Positioning</span> of Myosin VI on Endocytic Vesicles In Vivo</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">with vesicle-associated myosin VI existing as a processive dimer, capable of its known trafficking function myosins are found in a variety of organisms from Caenorhabditis elegans to human, and in a variety of cell clathrin-mediated endocytosis, myosin VI is implicated in trafficking vesicles that have recently shed</p> <div class="credits"> <p class="dwt_author">Spudich, James A.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">359</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013MNRAS.432.1928T"> <span id="translatedtitle">Putting the <span class="hlt">precision</span> in <span class="hlt">precision</span> cosmology: How accurate should your data covariance matrix be?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Cosmological parameter estimation requires that the likelihood function of the data is accurately known. Assuming that cosmological large-scale structure power spectra data are multivariate Gaussian distributed, we show that the accuracy of parameter estimation is limited by the accuracy of the inverse data covariance matrix - the <span class="hlt">precision</span> matrix. If the data covariance and <span class="hlt">precision</span> matrices are estimated by sampling independent realizations of the data, their statistical properties are described by the Wishart and inverse-Wishart distributions, respectively. Independent of any details of the survey, we show that the fractional error on a parameter variance, or a figure of merit, is equal to the fractional variance of the <span class="hlt">precision</span> matrix. In addition, for the only unbiased estimator of the <span class="hlt">precision</span> matrix, we find that the fractional accuracy of the parameter error depends only on the difference between the number of independent realizations and the number of data <span class="hlt">points</span>, and so can easily diverge. For a 5 per cent error on a parameter error and ND ? 102 data <span class="hlt">points</span>, a minimum of 200 realizations of the survey are needed, with 10 per cent accuracy in the data covariance. If the number of data <span class="hlt">points</span> ND ? 102, we need NS > ND realizations and a fractional accuracy of <?{2/N_D} in the data covariance. As the number of power spectra data <span class="hlt">points</span> grows to ND > 104-106, this approach will be problematic. We discuss possible ways to relax these conditions: improved theoretical modelling, shrinkage methods, data compression, simulation and data resampling methods.</p> <div class="credits"> <p class="dwt_author">Taylor, Andy; Joachimi, Benjamin; Kitching, Thomas</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">360</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/867295"> <span id="translatedtitle"><span class="hlt">Precision</span> alignment device</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">Apparatus for providing automatic alignment of beam devices having an associated structure for directing, collimating, focusing, reflecting, or otherwise modifying the main beam. A reference laser is attached to the structure enclosing the main beam producing apparatus and produces a reference beam substantially parallel to the main beam. Detector modules containing optical switching devices and optical detectors are <span class="hlt">positioned</span> in the path of the reference beam and are effective to produce an electrical output indicative of the alignment of the main beam. This electrical output drives servomotor operated adjustment screws to adjust the <span class="hlt">position</span> of elements of the structure associated with the main beam to maintain alignment of the main beam.</p> <div class="credits"> <p class="dwt_author">Jones, Nelson E. (Huntington Beach, CA)</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_17");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return 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href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a style="font-weight: bold;">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_20");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">361</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/6178080"> <span id="translatedtitle"><span class="hlt">Precision</span> alignment device</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">Apparatus for providing automatic alignment of beam devices having an associated structure for directing, collimating, focusing, reflecting, or otherwise modifying the main beam. A reference laser is attached to the structure enclosing the main beam producing apparatus and produces a reference beam substantially parallel to the main beam. Detector modules containing optical switching devices and optical detectors are <span class="hlt">positioned</span> in the path of the reference beam and are effective to produce an electrical output indicative of the alignment of the main beam. This electrical output drives servomotor operated adjustment screws to adjust the <span class="hlt">position</span> of elements of the structure associated with the main beam to maintain alignment of the main beam. 5 figs.</p> <div class="credits"> <p class="dwt_author">Jones, N.E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-03-10</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">362</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014SPIE.8967E..1BF"> <span id="translatedtitle">High <span class="hlt">precision</span> laser forming for microactuation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">For assembly of micro-devices, such as photonic devices, the <span class="hlt">precision</span> alignment of components is often critical for their performance. Laser forming, also known as laser-adjusting, can be used to create an integrated microactuator to align the components with sub-micron <span class="hlt">precision</span> after bonding. In this paper a so-called three-bridge planar manipulator was used to study the laser-material interaction and thermal and mechanical behavior of the laser forming mechanism. A 3-D Finite Element Method (FEM) model and experiments are used to identify the optimal parameter settings for a high <span class="hlt">precision</span> actuator. The goal in this paper is to investigate how <span class="hlt">precise</span> the maximum occurring temperature and the resulting displacement are predicted by a 3-D FEM model by comparing with experimental results. A secondary goal is to investigate the resolution of the mechanism and the range of motion. With the experimental setup we measure the displacement and surface temperature in real-time. The time-dependent heat transfer FEM models match closely with experimental results, however the structural model can deviate more than 100% in absolute displacement. Experimentally, a <span class="hlt">positioning</span> resolution of 0.1?m was achieved, with a total stroke exceeding 20?m. A spread of 10% in the temperature cycles between several experiments was found, which was attributed to a spread in the surface absorptivity. Combined with geometric tolerances, the spread in displacement can be as large as 20%. This implies that feedback control of the laser power, in combination with iterative learning during <span class="hlt">positioning</span>, is required for high <span class="hlt">precision</span> alignment. Even though the FEM models deviate substantially from the experiments, the 3-D FEM model predicts the trend in deformation sufficiently accurate to use it for design optimization of high <span class="hlt">precision</span> 3-D actuators using laser adjusting.</p> <div class="credits"> <p class="dwt_author">Folkersma, Ger K. G. P.; Römer, G. R. B. E.; Brouwer, D. M.; Huis in't Veld, A. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">363</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40191253"> <span id="translatedtitle">Modeling GPS satellite attitude variation for <span class="hlt">precise</span> orbit determination</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">High <span class="hlt">precision</span> geodetic application of the Global <span class="hlt">Positioning</span> System (GPS) require highly <span class="hlt">precise</span> ephemerides of the GPS satellites. An accurate model for the non-gravitational forces on the GPS satellites is a key to high quality GPS orbit determination, especially in long arcs. In this paper the effect of the satellite solar panel orientation error is investigated. These effects are approximated</p> <div class="credits"> <p class="dwt_author">D. Kuang; H. J. Rim; B. E. Schutz; P. A. M. Abusali</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">364</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/887240"> <span id="translatedtitle">Profile guided code <span class="hlt">positioning</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper presents the results of our investigation of code <span class="hlt">positioning</span> techniques using execution profile data as input into the compilation process. The primary objective of the <span class="hlt">positioning</span> is to reduce the overhead of the instruction memory hierarchy.After initial investigation in the literature, we decided to implement two prototypes for the Hewlett-Packard <span class="hlt">Precision</span> Architecture (PA-RISC). The first, built on top</p> <div class="credits"> <p class="dwt_author">Karl Pettis; Robert C. Hansen; Jack W. Davidson</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">365</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/15014557"> <span id="translatedtitle">Optimal Centroid <span class="hlt">Position</span> Estimation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The alignment of high energy laser beams for potential fusion experiments demand high <span class="hlt">precision</span> and accuracy by the underlying <span class="hlt">positioning</span> algorithms. This paper discusses the feasibility of employing online optimal <span class="hlt">position</span> estimators in the form of model-based processors to achieve the desired results. Here we discuss the modeling, development, implementation and processing of model-based processors applied to both simulated and actual beam line data.</p> <div class="credits"> <p class="dwt_author">Candy, J V; McClay, W A; Awwal, A S; Ferguson, S W</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-07-23</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">366</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/9664"> <span id="translatedtitle"><span class="hlt">Precision</span> flyer initiator</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A propulsion <span class="hlt">point</span> design is presented for lifting geological samples from Mars. Vehicle complexity is kept low by choosing a monopropellant single stage. Little new development is needed, as miniature pump fed hydrazine has been demonstrated. Loading the propellant just prior to operation avoids structural, thermal, and safety constraints otherwise imposed by earlier mission phases. hardware mass and engineering effort are thereby diminished. The Mars liftoff mass is 7/8 hydrazine, <5% propulsion hardware, and >3% each for the payload and guidance.</p> <div class="credits"> <p class="dwt_author">Frank, A</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-04-19</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">367</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012SPIE.8562E..1FX"> <span id="translatedtitle">A novel target LOS calibration method for IR scanning sensor based on control <span class="hlt">points</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Space based IR system uses the information of target LOS (line of sight) for target location. Recent researches show that the measuring <span class="hlt">precision</span> of target LOS is usually determined by measuring <span class="hlt">precision</span> of platform's <span class="hlt">position</span> and attitude, and deformation of sensor etc. Most methods for improving target location <span class="hlt">precision</span> are either through improving platform's <span class="hlt">position</span> and attitude measuring <span class="hlt">precision</span> or through calib rating the whole image obtained by IR sensor. With the development of measuring technology, it is harder to make a further improvement on the measuring <span class="hlt">precision</span> of <span class="hlt">position</span> and attitude of the platform and the expansion of the sensor view make calibrat ion of the whole image with a larger computation cost. In this paper, a method using control <span class="hlt">points</span> to calibrate target LOS was proposed. Based on the analysis of the imaging process of the scanning sensor of space based IR system, this paper established a modify model of target LOS based on control <span class="hlt">points</span>, used a bias filter to estimate the bias value of sensor boresight, and finally achieved the mission of target LOS calibrat ion. Different from the traditional calibration method of remote sensing image, the proposed method only made a correct ion on the LOS of suspicious target, but not established the accurate relationship between the all pixels and their real location, and has a similar calibration performance, but more lower computational complexity.</p> <div class="credits"> <p class="dwt_author">Xue, Yong-Hong; An, Wei; Zhang, Yin-Sheng; Zhang, Tao</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">368</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dspace.mit.edu/handle/1721.1/27878"> <span id="translatedtitle">Design of ultra <span class="hlt">precision</span> fixtures for nano-manufacturing</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">This thesis presents the design, modeling, fabrication and experimental validation of an active <span class="hlt">precision</span> fixturing system called the Hybrid <span class="hlt">Positioning</span> Fixture (HPF). The HPF uses the principles of exact constraint, ...</p> <div class="credits"> <p class="dwt_author">Mangudi Varadarajan, Kartik, 1981-</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">369</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/25310120"> <span id="translatedtitle">Does Provision of <span class="hlt">Point</span>-of-Care CD4 Technology and Early Knowledge of CD4 Levels Affect Early Initiation and Retention on Antiretroviral Treatment in HIV-<span class="hlt">Positive</span> Pregnant Women in the Context of Option B+ for PMTCT?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">: Evidence for Elimination (E4E) is a collaborative project established in 2012 as part of the INSPIRE (INtegrating and Scaling up PMTCT through Implementation REsearch) initiative. E4E is a cluster-randomized trial with 2 arms; Standard of care and "POC Plus" [in which <span class="hlt">point</span>-of-care (POC) CD4 devices and related counseling support are provided]; aimed at improving retention-in-care of HIV-infected pregnant women and mothers. In November 2013, Zimbabwe adopted Option B+ for HIV-<span class="hlt">positive</span> pregnant women under which antiretroviral treatment eligibility is no longer based on CD4 count. However, Ministry of Health and Child Care guidelines still require baseline and 6-monthly CD4 testing for treatment monitoring, until viral load testing becomes widely available. Considering the current limited capacity for viral-load testing, the significant investments in CD4 testing already made and the historical reliance on CD4 by health care workers for determining eligibility for antiretroviral treatment, E4E seeks to compare the impact of the provision of POC CD4 technology and early knowledge of CD4 levels on retention-in-care at 12 months, with the current standard of routine, laboratory-based CD4 testing. The study also compares rates of initiation and time-to-initiation between the 2 arms and according to level of maternal CD4 count, the cost of retaining HIV-<span class="hlt">positive</span> pregnant women in care and the acceptability and feasibility of POC CD4 in the context of Option B+. Outcome measures are derived from routine health systems data. E4E will provide data on POC CD4 testing and retention-in-care associated with Option B+ and serve as an early learning platform to inform implementation of Option B+ in Zimbabwe. PMID:25310120</p> <div class="credits"> <p class="dwt_author">Mangwiro, Alexio-Zambezi; Makomva, Kudzai; Bhattacharya, Antoinette; Bhattacharya, Gaurav; Gotora, Tendai; Owen, Mila; Mushavi, Angela; Mangwanya, Douglas; Zinyowera, Sekesai; Rusakaniko, Simbarashe; Mugurungi, Owen; Zizhou, Simukai; Busumani, William; Masuka, Nyasha</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">370</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19860036361&hterms=A-GPS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DA-GPS"> <span id="translatedtitle">A GPS measurement system for <span class="hlt">precise</span> satellite tracking and geodesy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">NASA is pursuing two key applications of differential <span class="hlt">positioning</span> with the Global <span class="hlt">Positioning</span> System (GPS): sub-decimeter tracking of earth satellites and few-centimeter determination of ground-fixed baselines. Key requirements of the two applications include the use of dual-frequency carrier phase data, multiple ground receivers to serve as reference <span class="hlt">points</span>, simultaneous solution for use <span class="hlt">position</span> and GPS orbits, and calibration of atmospheric delays using water vapor radiometers. Sub-decimeter tracking will be first demonstrated on the TOPEX oceanographic satellite to be launched in 1991. A GPS flight receiver together with at least six ground receivers will acquire delta range data from the GPS carriers for non-real-time analysis. Altitude accuracies of 5 to 10 cm are expected. For baseline measurements, efforts will be made to obtain <span class="hlt">precise</span> differential pseudorange by resolving the cycle ambiguity in differential carrier phase. This could lead to accuracies of 2 or 3 cm over a few thousand kilometers. To achieve this, a high-performance receiver is being developed, along with improved calibration and data processing techniques. Demonstrations may begin in 1986.</p> <div class="credits"> <p class="dwt_author">Yunck, T. P.; Wu, S.-C.; Lichten, S. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">371</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008ASSL..349..263R"> <span id="translatedtitle">Technology for <span class="hlt">Precision</span> Gravity Measurements</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We discuss four technologies applicable to <span class="hlt">precision</span> measurements in space and on the ground. The first is our tracking frequency laser distance gauge (TFG), which we developed ca. 1990 for a spaceborne astrometric optical interferometer, <span class="hlt">POINTS</span>, and which we are using today for our principle of equivalence measurement (POEM), a laboratory test of the equivalence principle. The second is an extension of the TFG to use a semiconductor laser (SL-TFG) with the intention to make the instrument more robust and applicable to space-based experiments. In particular, we wish to apply the SL-TFG to a version of POEM that could operate in space at substantially higher accuracy. Further, some versions of the SL-TFG have reduced complexity and thus have enhanced reliability and reduced cost. The third technology is an approach to using the TFG as part of an extended spacebased optical instrument. We discuss the launching of multiple beams from a single device as a means of achieving a “strong optical truss” without excess complexity or endpoint connection error. The fourth and final technology is for creating a brief period of free fall in the laboratory, and being able to repeat the free-fall rapidly. This technology is a key part of POEM.</p> <div class="credits"> <p class="dwt_author">Reasenberg, Robert D.; Phillips, James D.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">372</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014PrPNP..75...41P"> <span id="translatedtitle"><span class="hlt">Precision</span> tau physics</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Precise</span> measurements of the lepton properties provide stringent tests of the Standard Model and accurate determinations of its parameters. We overview the present status of ? physics, highlighting the most recent developments, and discuss the prospects for future improvements. The leptonic decays of the ? lepton probe the structure of the weak currents and the universality of their couplings to the W boson. The universality of the leptonic Z couplings has also been tested through Z??+?- decays. The hadronic ? decay modes constitute an ideal tool for studying low-energy effects of the strong interaction in very clean conditions. Accurate determinations of the QCD coupling and the Cabibbo mixing V have been obtained with ? data. The large mass of the ? opens the possibility to study many kinematically-allowed exclusive decay modes and extract relevant dynamical information. Violations of flavour and CP conservation laws can also be searched for with ? decays. Related subjects such as ? decays, the electron and muon anomalous magnetic moments, neutrino mixing and B-meson decays into ? leptons are briefly covered. Being one the fermions most strongly coupled to the scalar sector, the ? lepton is playing now a very important role at the LHC as a tool to test the Higgs properties and search for new physics at higher scales.</p> <div class="credits"> <p class="dwt_author">Pich, Antonio</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">373</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://scpnt.stanford.edu/downloads/SCPNT_Briefing_Website_R3.pdf"> <span id="translatedtitle">Stanford Center for <span class="hlt">Position</span>, Navigation & Time</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Monitoring · <span class="hlt">Precision</span> survey, mapping, geodesy and seismic monitoring of earthquake faults. · Future. <span class="hlt">Position</span>, Navigation & Time Technology Critical to the global economy Time Technology · Broadband</p> <div class="credits"> <p class="dwt_author">Straight, Aaron</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">374</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/1955757"> <span id="translatedtitle">TMDs: Evolution, modeling, <span class="hlt">precision</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">The factorization theorem for $q_T$ spectra in Drell-Yan processes, boson production and semi-inclusive deep inelastic scattering allows for the determination of the non-perturbative parts of transverse momentum dependent parton distribution functions. Here we discuss the fit of Drell-Yan and $Z$-production data using the transverse momentum dependent formalism and the resummation of the evolution kernel. We find a good theoretical stability of the results and a final $\\chi^2/{\\rm <span class="hlt">points</span>}\\lesssim 1$. We show how the fixing of the non-perturbative pieces of the evolution can be used to make predictions at present and future colliders.</p> <div class="credits"> <p class="dwt_author">D'Alesio, Umberto; Melis, Stefano; Scimemi, Ignazio</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">375</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Goss%20International_0.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description.gossinternational.com Machinery Engineering Company Overview: Degree: Paid Fall, Spring, Summer Yes Career & Internship Fair innovation. Chemical Engineering, Computer Engineering, Computer Science, Electrical Engineering, Mechanical</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">376</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Dartmouth-Hitchock%20Med%20Center.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: Yes Career and Internship Fair March 5, 2013 & Clinical Practice. Business Administration, Chemistry, Computer Engineering, Computer Science, Health</p> <div class="credits"> <p class="dwt_author">Pringle, James "Jamie"</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">377</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Tyco%20International_2.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: Yes Career & Internship Fair October 22, 2013 Engineering, Computer Engineering, Computer Science, Mechanical Engineering Yes Entry Level</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">378</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Radianse_1.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: Yes Career & Internship Fair October 22, 2013, "Where did I leave my electrosurgical unit?" Computer Engineering, Computer Science, Electrical</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">379</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/EBSCO%20Information%20Services.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: Yes Career & Internship Fair October 22, 2013. Business Administration, Computer Engineering, Computer Science, Liberal Arts Majors No Entry Level</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">380</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Riverbed%20Technologies_1.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: Yes Career & Internship Fair October 22, 2013 at Riverbed. Computer Engineering, Computer Science, Electrical Engineering Yes Entry Level</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a 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class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career & Internship Fair October 22, 2013 Engineer (aerospace), .Net Developer, and Data Architect. Computer Engineering, Computer Science</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">382</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Linear%20Technology%20Corporation_0.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: Yes Career & Internship Fair October 22, 2013 sensor network products. Computer Engineering, Computer Science, Electrical Engineering Yes Entry Level</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">383</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Newforma.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career & Internship Fair October 22, 2013 efficient process. Business Administration, Civil Engineering, Computer Engineering, Computer Science</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">384</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Mitre.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career & Internship Fair October 22, 2013. Computer Engineering, Computer Science, Electrical Engineering, Math & Statistics, Physics Yes Entry Level</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">385</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Pegasystems_2.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career & Internship Fair October 22, 2013) software by leading industry analysts. Computer Engineering, Computer Science Yes Entry Level</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">386</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Tyler%20Tech.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description meetings. tylertech.com Technology Company Overview: Degree: Paid Summer Yes Career & Internship Fair Specialist Business Administration, Computer Engineering, Computer Science, Electrical Engineering, Math</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">387</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Taxware.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career & Internship Fair October 22, 2013 customer requirements. Business Administration, Computer Engineering, Computer Science, Economics, Liberal</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">388</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Merchants%20Fleet%20Management.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career & Internship Fair October 22, 2013 Administration, Computer Engineering, Computer Science, Health & Human Services, Hospitality, Liberal Arts Majors</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">389</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Kronos_1.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career & Internship Fair October 22, 2013 employer. Business Administration, Computer Science Yes Entry LevelInternships Summer internships</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">390</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/C&S%20Wholesale%20Grocers_2.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career & Internship Fair October 22, 2013 in its class. Business Administration, Computer Science, Economics, Electrical Engineering Yes Entry</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">391</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/18347722"> <span id="translatedtitle"><span class="hlt">Precision</span> steering of an optical trap by electro-optic deflection.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We designed, constructed, and tested a single-beam optical trapping instrument employing twin electro-optic deflectors (EODs) to steer the trap in the specimen plane. Compared with traditional instruments based on acousto-optic deflectors (AODs), EOD-based traps offer a significant improvement in light throughput and a reduction in deflection-angle (<span class="hlt">pointing</span>) errors. These attributes impart improved force and <span class="hlt">position</span> resolution, making EOD-based traps a promising alternative for high-<span class="hlt">precision</span> nanomechanical measurements of biomaterials. PMID:18347722</p> <div class="credits"> <p class="dwt_author">Valentine, Megan T; Guydosh, Nicholas R; Gutiérrez-Medina, Braulio; Fehr, Adrian N; Andreasson, Johan O; Block, Steven M</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-03-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">392</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54973070"> <span id="translatedtitle">Tipping <span class="hlt">Points</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A climate tipping <span class="hlt">point</span>, at least as I have used the phrase, refers to a situation in which a changing climate forcing has reached a <span class="hlt">point</span> such that little additional forcing (or global temperature change) is needed to cause large, relatively rapid, climate change. Present examples include potential loss of all Arctic sea ice and instability of the West Antarctic</p> <div class="credits"> <p class="dwt_author">J. Hansen</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">393</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007AGUFMGC44A..01H"> <span id="translatedtitle">Tipping <span class="hlt">Points</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A climate tipping <span class="hlt">point</span>, at least as I have used the phrase, refers to a situation in which a changing climate forcing has reached a <span class="hlt">point</span> such that little additional forcing (or global temperature change) is needed to cause large, relatively rapid, climate change. Present examples include potential loss of all Arctic sea ice and instability of the West Antarctic and Greenland ice sheets. Tipping <span class="hlt">points</span> are characterized by ready feedbacks that amplify the effect of forcings. The notion that these may be runaway feedbacks is a misconception. However, present "unrealized" global warming, due to the climate system's thermal inertia, exacerbates the difficulty of avoiding global warming tipping <span class="hlt">points</span>. I argue that prompt efforts to slow CO2 emissions and absolutely reduce non-CO2 forcings are both essential if we are to avoid tipping <span class="hlt">points</span> that would be disastrous for humanity and creation, the planet as civilization knows it.</p> <div class="credits"> <p class="dwt_author">Hansen, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">394</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011ESS.....2.4104S"> <span id="translatedtitle">Fiber Scrambling for Extreme Doppler <span class="hlt">Precision</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The detection of Earth-like exoplanets with the radial velocity method requires extreme Doppler <span class="hlt">precision</span> and long-term stability in order to measure tiny reflex velocities in the host star. Recent planet searches have led to the detection of so called “super-Earths” (up to a few Earth masses) that induce radial velocity changes of about 1 m/s. However, the detection of true Earth analogs requires a <span class="hlt">precision</span> of 10 cm/s. One of the factors limiting Doppler <span class="hlt">precision</span> is variation in the <span class="hlt">Point</span> Spread Function (PSF) from observation to observation due to changes in the illumination of the slit and spectrograph optics. Thus, this stability has become a focus of current instrumentation work. Fiber optics have been used since the 1980’s to couple telescopes to high-<span class="hlt">precision</span> spectrographs, initially for simpler mechanical design and control. However, fiber optics are also naturally efficient scramblers. Scrambling refers to a fiber’s ability to produce an output beam independent of input. Our research is focused on understanding the scrambling properties of fibers with different geometries (circular, square, octagonal), different lengths and fiber sizes. Another important parameter when it comes to fibers is the so-called focal ratio degradation (FRD), which accounts for a different (faster) focal ratio after the fiber than the one sent into the fiber. In this paper, we will present new insight on fiber scrambling, FRD and what we call fiber personality, which describes differing behaviors for supposedly identical fiber.</p> <div class="credits"> <p class="dwt_author">Spronck, Julien; Kaplan, Z.; Fischer, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">395</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/25330046"> <span id="translatedtitle">High-<span class="hlt">precision</span> image aided inertial navigation with known features: observability analysis and performance evaluation.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">A high-<span class="hlt">precision</span> image-aided inertial navigation system (INS) is proposed as an alternative to the carrier-phase-based differential Global Navigation Satellite Systems (CDGNSSs) when satellite-based navigation systems are unavailable. In this paper, the image/INS integrated algorithm is modeled by a tightly-coupled iterative extended Kalman filter (IEKF). Tightly-coupled integration ensures that the integrated system is reliable, even if few known feature <span class="hlt">points</span> (i.e., less than three) are observed in the images. A new global observability analysis of this tightly-coupled integration is presented to guarantee that the system is observable under the necessary conditions. The analysis conclusions were verified by simulations and field tests. The field tests also indicate that high-<span class="hlt">precision</span> <span class="hlt">position</span> (centimeter-level) and attitude (half-degree-level)-integrated solutions can be achieved in a global reference. PMID:25330046</p> <div class="credits"> <p class="dwt_author">Jiang, Weiping; Wang, Li; Niu, Xiaoji; Zhang, Quan; Zhang, Hui; Tang, Min; Hu, Xiangyun</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">396</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4239938"> <span id="translatedtitle">High-<span class="hlt">Precision</span> Image Aided Inertial Navigation with Known Features: Observability Analysis and Performance Evaluation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">A high-<span class="hlt">precision</span> image-aided inertial navigation system (INS) is proposed as an alternative to the carrier-phase-based differential Global Navigation Satellite Systems (CDGNSSs) when satellite-based navigation systems are unavailable. In this paper, the image/INS integrated algorithm is modeled by a tightly-coupled iterative extended Kalman filter (IEKF). Tightly-coupled integration ensures that the integrated system is reliable, even if few known feature <span class="hlt">points</span> (i.e., less than three) are observed in the images. A new global observability analysis of this tightly-coupled integration is presented to guarantee that the system is observable under the necessary conditions. The analysis conclusions were verified by simulations and field tests. The field tests also indicate that high-<span class="hlt">precision</span> <span class="hlt">position</span> (centimeter-level) and attitude (half-degree-level)-integrated solutions can be achieved in a global reference. PMID:25330046</p> <div class="credits"> <p class="dwt_author">Jiang, Weiping; Wang, Li; Niu, Xiaoji; Zhang, Quan; Zhang, Hui; Tang, Min; Hu, Xiangyun</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">397</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/1387865"> <span id="translatedtitle"><span class="hlt">Precise</span> Exceptions in Asynchronous Processors</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The presence of <span class="hlt">precise</span> exceptions in a processor leads to co mplications in its design. Some re- cent processor architectures have sacrificed this requirem ent for performance reasons at the cost of software complexity. We present an implementation strateg y for <span class="hlt">precise</span> exceptions in asynchronous processors that does not block the instruction fetch when ex ceptions do not occur; the</p> <div class="credits"> <p class="dwt_author">Rajit Manohar; Mika Nyström; Alain J. Martin</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">398</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19860000049&hterms=effusion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Deffusion"> <span id="translatedtitle"><span class="hlt">Precise</span>-Conductance Valve Insert</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Valve modification provides two operating modes fully open and small, <span class="hlt">precise</span> leak. Copper insert with radially oriented holes allows small, controllable, <span class="hlt">precise</span> effusion rate when valve closed or nearly unobstructed flow when valve open. Numerous applications in surface physics, vacuum physics, materials science, gas kinetics, thin films, and other areas of research requiring measured flows of gas into or out of system.</p> <div class="credits"> <p class="dwt_author">Outlaw, R. A.; Hoyt, R. F.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">399</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012SCPMA..55.2290Z"> <span id="translatedtitle"><span class="hlt">Positioning</span> accuracy assessment for the 4GEO/5IGSO/2MEO constellation of COMPASS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Determined to become a new member of the well-established GNSS family, COMPASS (or BeiDou-2) is developing its capabilities to provide high accuracy <span class="hlt">positioning</span> services. Two <span class="hlt">positioning</span> modes are investigated in this study to assess the <span class="hlt">positioning</span> accuracy of COMPASS' 4GEO/5IGSO/2MEO constellation. <span class="hlt">Precise</span> <span class="hlt">Point</span> <span class="hlt">Positioning</span> (PPP) for geodetic users and real-time <span class="hlt">positioning</span> for common navigation users are utilized. To evaluate PPP accuracy, coordinate time series repeatability and discrepancies with GPS' <span class="hlt">precise</span> <span class="hlt">positioning</span> are computed. Experiments show that COMPASS PPP repeatability for the east, north and up components of a receiver within mainland China is better than 2 cm, 2 cm and 5 cm, respectively. Apparent systematic offsets of several centimeters exist between COMPASS <span class="hlt">precise</span> <span class="hlt">positioning</span> and GPS <span class="hlt">precise</span> <span class="hlt">positioning</span>, indicating errors remaining in the treatments of COMPASS measurement and dynamic models and reference frame differences existing between two systems. For common <span class="hlt">positioning</span> users, COMPASS provides both open and authorized services with rapid differential corrections and integrity information available to authorized users. Our assessment shows that in open service <span class="hlt">positioning</span> accuracy of dual-frequency and single-frequency users is about 5 m and 6 m (RMS), respectively, which may be improved to about 3 m and 4 m (RMS) with the addition of differential corrections. Less accurate Signal In Space User Ranging Error (SIS URE) and Geometric Dilution of <span class="hlt">Precision</span> (GDOP) contribute to the relatively inferior accuracy of COMPASS as compared to GPS. Since the deployment of the remaining 1 GEO and 2 MEO is not able to significantly improve GDOP, the performance gap could only be overcome either by the use of differential corrections or improvement of the SIS URE, or both.</p> <div class="credits"> <p class="dwt_author">Zhou, ShanShi; Cao, YueLing; Zhou, JianHua; Hu, XiaoGong; Tang, ChengPan; Liu, Li; Guo, Rui; He, Feng; Chen, JunPing; Wu, Bin</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">400</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004DPS....36.1426H"> <span id="translatedtitle">Low Cost <span class="hlt">Precision</span> Lander for Lunar Exploration</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">For 60 years the US Defense Department has invested heavily in producing small, low mass, <span class="hlt">precision</span>-guided vehicles. The technologies matured under these programs include terrain-aided navigation, closed loop terminal guidance algorithms, robust autopilots, high thrust-to-weight propulsion, autonomous mission management software, sensors, and data fusion. These technologies will aid NASA in addressing New Millennium Science and Technology goals as well as the requirements flowing from the Moon to Mars vision articulated in January 2004. Establishing and resupplying a long-term lunar presence will require automated landing <span class="hlt">precision</span> not yet demonstrated. <span class="hlt">Precision</span> landing will increase safety and assure mission success. In our lander design, science instruments amount to 10 kg, 16% of the lander vehicle mass. This compares favorably with 7% for Mars Pathfinder and less than 15% for Surveyor. The mission design relies on a cruise stage for navigation and TCMs for the lander's flight to the moon. The landing sequence begins with a solid motor burn to reduce the vehicle speed to 300-450 m/s. At this <span class="hlt">point</span> the lander is about 2 minutes from touchdown and has 600 to 700 m/s delta-v capability. This allows for about 10 km of vehicle divert during terminal descent. This concept of operations closely mimics missile operational protocol used for decades: the vehicle remains inert, then must execute its mission flawlessly on a moment's notice. The vehicle design uses a propulsion system derived from heritage MDA programs. A redesigned truss provides hard <span class="hlt">points</span> for landing gear, electronics, power supply, and science instruments. A radar altimeter and a Digital Scene Matching Area Correlator (DSMAC) provide data for the terminal guidance algorithms. This approach leverages the billions of dollars DoD has invested in these technologies, to land useful science payloads <span class="hlt">precisely</span> on the lunar surface at relatively low cost.</p> <div class="credits"> <p class="dwt_author">Hoppa, G. V.; Head, J. N.; Gardner, T. G.; Seybold, K. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_19");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">401</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014SPIE.8982E..0YC"> <span id="translatedtitle">Fast and <span class="hlt">precise</span> continuous focusing with focus tunable lenses</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Focusing in milliseconds without translational mechanics involved is possible with electrically tunable lenses. Fast shape-changing lenses enable fast imaging systems which can focus at distances from infinity to a few centimeters with a high optical quality. Furthermore, rapid laser processing in three dimensions is realized without mechanical translation of the focusing lens or the sample. With tunable lenses the entire optics can be made compact, robust and abrasion-free. Different configurations are discussed, how to integrate the tunable lens in the optical path. For machine vision applications, the achievable optical quality depends on the chosen combination of the tunable lens with a fixed focal length lens and a camera. It is recommended to use a fixed focus lens with a short distance between the stop <span class="hlt">position</span> and the front of the lens. Furthermore, important <span class="hlt">points</span> are presented how to achieve optimal performance in laser processing applications such as orientation and <span class="hlt">position</span> of the tunable lens and the diameter of the beam incident on the lens. Additionally, different approaches will be discussed for monitoring the focal length of the tunable lens. The focal length of the tunable lens is sensitive to temperature changes, as the lens material is a fluid. However, in contrast to conventional lenses, the focal length of the tunable lens can be corrected electrically. For that purpose, the tunable lens exhibits an integrated temperature sensor for temperature compensation. Also optical feedback solutions will be presented for applications requiring highest <span class="hlt">precision</span> and tracking of the absolute focal length value.</p> <div class="credits"> <p class="dwt_author">Casutt, Selina; Bueeler, Michael; Blum, Mark; Aschwanden, Manuel</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">402</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/astro-ph/0006325v1"> <span id="translatedtitle">Toward High-<span class="hlt">Precision</span> Astrometry with WFPC2. I. Deriving an Accurate PSF</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">The first step toward doing high-<span class="hlt">precision</span> astrometry is the measurement of individual stars in individual images, a step that is fraught with dangers when the images are undersampled. The key to avoiding systematic <span class="hlt">positional</span> error in undersampled images is to determine an extremely accurate <span class="hlt">point</span>-spread function (PSF). We apply the concept of the {\\it effective} PSF, and show that in images that consist of pixels it is the ePSF, rather than the often-used instrumental PSF, that embodies the information from which accurate star <span class="hlt">positions</span> and magnitudes can be derived. We show how, in a rich star field, one can use the information from dithered exposures to derive an extremely accurate effective PSF by iterating between the PSF itself and the star <span class="hlt">positions</span> that we measure with it. We also give a simple but effective procedure for representing spatial variations of the HST PSF. With such attention to the PSF, we find that we are able to measure the <span class="hlt">position</span> of a single reasonably bright star in a single image with a <span class="hlt">precision</span> of 0.02 pixel (2 mas in WF frames, 1 mas in PC), but with a systematic accuracy better than 0.002 pixel (0.2 mas in WF, 0.1 mas in PC), so that multiple observations can reliably be combined to improve the accuracy by $\\surd N$.</p> <div class="credits"> <p class="dwt_author">Jay Anderson; Ivan R. King</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-06-22</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">403</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/6120401"> <span id="translatedtitle">High <span class="hlt">precision</span> beam alignment of electromagnetic wigglers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The performance of Free-Electron Lasers depends critically on the quality of the alignment of the electron beam to the wiggler's magnetic axis and the deviation of this axis from a straight fine. The measurement of the electron beam <span class="hlt">position</span> requires numerous beam <span class="hlt">position</span> monitors in the wiggler, where space is at premium. The beam <span class="hlt">position</span> measurement is used to set beam steerers for an orbit correction in the wiggler. The authors propose an alternative high <span class="hlt">precision</span> alignment method in which one or two external Beam <span class="hlt">Position</span> Monitors (BPM) are used. In this technique, the field in the electro-wiggler is modulated section by section and the beam <span class="hlt">position</span> movement at the external BPM is detected in synchronism with the modulation. A beam offset at the modulated beam section will produce a modulation of the beam <span class="hlt">position</span> at the detector that is a function of the of the beam offset and the absolute value of the modulation current. The wiggler errors produce a modulation that is a function of the modulation current. It will be shown that this method allows the detection and correction of the beam <span class="hlt">position</span> at each section in the presence of wiggler errors with a good resolution. Furthermore, it allows one to measure the first and second integrals of the wiggler error over each wiggler section. Lastly, provided that wiggler sections can be degaussed effectively, one can test the deviation of the wiggler's magnetic axis from a straight line.</p> <div class="credits"> <p class="dwt_author">Ben-Zvi, I.; Qiu, X.Z.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">404</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20130014732&hterms=basis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbasis"> <span id="translatedtitle">The GLAS Algorithm Theoretical Basis Document for <span class="hlt">Precision</span> Orbit Determination (POD)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The Geoscience Laser Altimeter System (GLAS) was the sole instrument for NASA's Ice, Cloud and land Elevation Satellite (ICESat) laser altimetry mission. The primary purpose of the ICESat mission was to make ice sheet elevation measurements of the polar regions. Additional goals were to measure the global distribution of clouds and aerosols and to map sea ice, land topography and vegetation. ICESat was the benchmark Earth Observing System (EOS) mission to be used to determine the mass balance of the ice sheets, as well as for providing cloud property information, especially for stratospheric clouds common over polar areas. The GLAS instrument operated from 2003 to 2009 and provided multi-year elevation data needed to determine changes in sea ice freeboard, land topography and vegetation around the globe, in addition to elevation changes of the Greenland and Antarctic ice sheets. This document describes the <span class="hlt">Precision</span> Orbit Determination (POD) algorithm for the ICESat mission. The problem of determining an accurate ephemeris for an orbiting satellite involves estimating the <span class="hlt">position</span> and velocity of the satellite from a sequence of observations. The ICESatGLAS elevation measurements must be very accurately geolocated, combining <span class="hlt">precise</span> orbit information with <span class="hlt">precision</span> <span class="hlt">pointing</span> information. The ICESat mission POD requirement states that the <span class="hlt">position</span> of the instrument should be determined with an accuracy of 5 and 20 cm (1-s) in radial and horizontal components, respectively, to meet the science requirements for determining elevation change.</p> <div class="credits"> <p class="dwt_author">Rim, Hyung Jin; Yoon, S. P.; Schultz, Bob E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">405</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5436996"> <span id="translatedtitle"><span class="hlt">Precise</span> seabed emplacement of an articulated loading platform in the North Sea</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The Statfjord B articulated loading platform is a single <span class="hlt">point</span> mooring (SPM) consisting essentially of three principal components: gravity base, cylindrical column and rotating head. Built in West Germany and assembled in a Norwegian fjord, the unit was towed to the Statfjord B site and installed <span class="hlt">precisely</span> adjacent to a seabed valve station and a previously laid sealine in August, 1982. Prior to arrival of the SPM at the site two piles had been driven into the seabed adjacent to the subsea valve station against which the SPM's gravity base was to be docked. Two matching guides had been incorporated in the gravity base for the purpose of mating with the piles. The SPM was maneuvered into <span class="hlt">position</span> and held steady by three tugboats. A diving support vessel moored on location was equipped with two hydraulic heave compensating winches from which wire ropes were led vertically and fed through sheaves on the valve station to the SPM base. By maintaining constant tension on the pull-in wires and slowly paying out the tug towlines the gravity base was <span class="hlt">positioned</span> <span class="hlt">precisely</span> with respect to the horizontal axes and heading by mating the guides with the piles. Touchdown and skirt penetration were achieved by controlled ballasting of the column with water. An integrated acoustic transponder system provided <span class="hlt">precise</span> real time data on SPM <span class="hlt">position</span>, base and column angles and under-keel clearance. Final approach was monitored by means of closed circuit television (CCTV). This paper describes the technique developed to install the large structure with a very high degree of <span class="hlt">precision</span> in two horizontal axes and in azimuth.</p> <div class="credits"> <p class="dwt_author">Noblanc, A.; Schnader, H.E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">406</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52947075"> <span id="translatedtitle">Ionospheric specification algorithms for <span class="hlt">precise</span> GPS-based aircraft navigation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Federal Aviation Administration (FAA) is implementing an aircraft navigation scheme for the United States using the Global <span class="hlt">Positioning</span> System (GPS) L1 signal (1575.42 MHz). To achieve <span class="hlt">position</span> accuracies of a few meters, sufficient to allow <span class="hlt">precision</span> airfield approaches, it will be necessary to broadcast corrections to the direct GPS signal. A significant component of these corrections is the delay</p> <div class="credits"> <p class="dwt_author">I. L. Harris; A. J. Mannucci; B. A. Iijima; U. J. Lindqwister; D. Muna; X. Pi; B. D. Wilson</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">407</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/6049501"> <span id="translatedtitle">An integrated reduction technique for a double <span class="hlt">precision</span> accumulator</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The accumulation operation, An+1 = An + X, is perhaps one of the most fundamental and widely-used operations in numerical mathematics and digital signal processing. However, designing double-<span class="hlt">precision</span> floating-<span class="hlt">point</span> accumulators presents a unique set of challenges: double-<span class="hlt">precision</span> addition is usually deeply pipelined and without special micro-architectural or data scheduling techniques, the data hazard that exists between An+1 and An requires</p> <div class="credits"> <p class="dwt_author">Krishna K. Nagar; Yan Zhang; Jason D. Bakos</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">408</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/817634"> <span id="translatedtitle">ARPREC: An arbitrary <span class="hlt">precision</span> computation package</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This paper describes a new software package for performing arithmetic with an arbitrarily high level of numeric <span class="hlt">precision</span>. It is based on the earlier MPFUN package, enhanced with special IEEE floating-<span class="hlt">point</span> numerical techniques and several new functions. This package is written in C++ code for high performance and broad portability and includes both C++ and Fortran-90 translation modules, so that conventional C++ and Fortran-90 programs can utilize the package with only very minor changes. This paper includes a survey of some of the interesting applications of this package and its predecessors.</p> <div class="credits"> <p class="dwt_author">Bailey, David H.; Yozo, Hida; Li, Xiaoye S.; Thompson, Brandon</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">409</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/896161"> <span id="translatedtitle"><span class="hlt">Precision</span> Measurements at the ILC</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">With relatively low backgrounds and a well-determined initial state, the proposed International Linear Collider (ILC) would provide a <span class="hlt">precision</span> complement to the LHC experiments at the energy frontier. Completely and <span class="hlt">precisely</span> exploring the discoveries of the LHC with such a machine will be critical in understanding the nature of those discoveries and what, if any, new physics they represent. The unique ability to form a complete picture of the Higgs sector is a prime example of the probative power of the ILC and represents a new era in <span class="hlt">precision</span> physics.</p> <div class="credits"> <p class="dwt_author">Nelson, T.K.; /SLAC</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-06</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">410</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1992SPIE.1709..493V"> <span id="translatedtitle">Automated <span class="hlt">precision</span> assembly through neurovision</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this study an intelligent control architecture is proposed for recognition and diagnosis of digital images captured by the vision system to control the robot manipulator in automated <span class="hlt">precision</span> assembly. The architecture proposed provides enough flexibility to the assembly cell in processing a wide variety of products that require <span class="hlt">precision</span> assembly. The system uses ART paradigm for part recognition and backpropagation for calibration. System architecture is tested using an IBM 7547 robot with a CCD camera for <span class="hlt">precision</span> assembly of a printed circuit board (PCB) and satisfactory results are obtained.</p> <div class="credits"> <p class="dwt_author">Vellanki, Mahesh K.; Dagli, Cihan H.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">411</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20100024410&hterms=motion+sensor+lights&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmotion%2Bsensor%2Blights"> <span id="translatedtitle">Optical <span class="hlt">Pointing</span> Sensor</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The optical <span class="hlt">pointing</span> sensor provides a means of directly measuring the relative <span class="hlt">positions</span> of JPL s Formation Control Testbed (FCT) vehicles without communication. This innovation is a steerable infrared (IR) rangefinder that gives measurements in terms of range and bearing to a passive retroreflector.</p> <div class="credits"> <p class="dwt_author">Shields, Joel F.; Metz, Brandon C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">412</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=newtonian&pg=4&id=EJ766053"> <span id="translatedtitle">The Lagrange <span class="hlt">Points</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">This paper presents a derivation of all five Lagrange <span class="hlt">points</span> by methods accessible to sixth-form students, and provides a further opportunity to match Newtonian gravity with centripetal force. The predictive powers of good scientific theories are also discussed with regard to the philosophy of science. Methods for calculating the <span class="hlt">positions</span> of the…</p> <div class="credits"> <p class="dwt_author">Lovell, M.S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">413</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..1612353D"> <span id="translatedtitle"><span class="hlt">Precise</span> orbit determination of Multi-GNSS constellation including GPS GLONASS BDS and GALIEO</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In addition to the existing American global <span class="hlt">positioning</span> system (GPS) and the Russian global navigation satellite system (GLONASS), the new generation of GNSS is emerging and developing, such as the Chinese BeiDou satellite navigation system (BDS) and the European GALILEO system. Multi-constellation is expected to contribute to more accurate and reliable <span class="hlt">positioning</span> and navigation service. However, the application of multi-constellation challenges the traditional <span class="hlt">precise</span> orbit determination (POD) strategy that was designed usually for single constellation. In this contribution, we exploit a more rigorous multi-constellation POD strategy for the ongoing IGS multi-GNSS experiment (MGEX) where the common parameters are identical for each system, and the frequency- and system-specified parameters are employed to account for the inter-frequency and inter-system biases. Since the authorized BDS attitude model is not yet released, different BDS attitude model are implemented and their impact on orbit accuracy are studied. The proposed POD strategy was implemented in the PANDA (<span class="hlt">Position</span> and Navigation Data Analyst) software and can process observations from GPS, GLONASS, BDS and GALILEO together. The strategy is evaluated with the multi-constellation observations from about 90 MGEX stations and BDS observations from the BeiDou experimental tracking network (BETN) of Wuhan University (WHU). Of all the MGEX stations, 28 stations record BDS observation, and about 80 stations record GALILEO observations. All these data were processed together in our software, resulting in the multi-constellation POD solutions. We assessed the orbit accuracy for GPS and GLONASS by comparing our solutions with the IGS final orbit, and for BDS and GALILEO by overlapping our daily orbit solution. The stability of inter-frequency bias of GLONASS and inter-system biases w.r.t. GPS for GLONASS, BDS and GALILEO were investigated. At last, we carried out <span class="hlt">precise</span> <span class="hlt">point</span> <span class="hlt">positioning</span> (PPP) using the multi-constellation POD orbit and clock products, and analyzed the contribution of these POD products to PPP. Keywords: Multi-GNSS, <span class="hlt">Precise</span> Orbit Determination, Inter-frequency bias, Inter-system bias, <span class="hlt">Precise</span> <span class="hlt">Point</span> <span class="hlt">Positioning</span></p> <div class="credits"> <p class="dwt_author">Dai, Xiaolei</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">414</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.exploratorium.edu/snacks/curie_point/"> <span id="translatedtitle">Curie <span class="hlt">Point</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">In this activity best suited as a demonstration, learners observe that when a piece of iron gets too hot, it loses its ability to be magnetized. The temperature at which this occurs is known as the Curie <span class="hlt">Point</span>. This simple set-up involving a lantern battery and Tinkertoys⢠demonstrates this phenomenon. Adult supervision required, as the wire will get hot in this activity.</p> <div class="credits"> <p class="dwt_author">Exploratorium, The</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-30</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">415</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://concord.org/stem-resources/dew-point"> <span id="translatedtitle">Dew <span class="hlt">Point</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Determine the dew <span class="hlt">point</span> temperature for your classroom through a hands-on experiment. Use humidity and temperature probes to investigate the temperature at which it would rain in your classroom! Learn about water density and the conditions necessary to produce fog or rain.</p> <div class="credits"> <p class="dwt_author">Consortium, The C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-13</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">416</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Enterasys_2.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description products have a 98% Customer Satisfaction rating! Due to growth we have moved our headquarters to a new 180&D, QA, Customer Service, Marketing and Product Management departments are not out-sourced. Our GTAC team</p> <div class="credits"> <p class="dwt_author">Pringle, James "Jamie"</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">417</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/59185921"> <span id="translatedtitle"><span class="hlt">Positive</span> Psychology \\</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Positive</span> psychology is the study of human strength, resilience, and optimal human functioning. The goal of <span class="hlt">positive</span> psychology is to make people happier by understanding and building <span class="hlt">positive</span> emotion, gratification and meaning. The constructs of happiness, hope, optimism, well-being, resilience and flow are examined in how they relate to <span class="hlt">positive</span> psychology. The \\</p> <div class="credits"> <p class="dwt_author">Andrew W Fleming</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">418</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Profit%20Tools.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career & Internship Fair October 22, 2013 are our top priority, and team members are our greatest asset! Computer Engineering, Computer Science</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">419</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Center%20for%20Wildlife_1.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description Ecology or Management, Environmental Science, or Veterinary Science. The large number of animals.yorkcenterforwildlife.org Wildlife Rehabilitation Company Overview: Degree: Unpaid Fall, Spring, Summer No Career & Internship Fair</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">420</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Weston%20&%20Sampson_1.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description of Science Program in Civil Engineering or related engineering fields. 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Computer Engineering, Computer Science, Electrical</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">422</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/B2W%20Software,%20Inc..pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career & Internship Fair October 22, 2013 and dispatching and asset maintenance. 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Computer Science Yes Entry LevelInternships Software Intern Whittemore Center Jacobs Technology</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">425</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Arista%20Networks.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: Yes Career & Internship Fair October 22, 2013, and dramatically change the price/performance of data center networks. Computer Engineering, Computer Science</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">426</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/MMIS,%20Inc._0.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career & Internship Fair October 22, 2013 in providing innovative products and services to the life science market. Our SaaS based business collaboration</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">427</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Oracle_4.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description/Hardware Company Overview: Degree: No Career & Internship Fair October 22, 2013 -- 12:00-4:00pm Yes Pre of ownership. Computer Engineering, Computer Science No Entry LevelInternships Whittemore Center Oracle</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">428</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/General%20Dynamics%20Electric%20Boat_0.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career & Internship Fair October 22, 2013 submarine technology to a new level. Civil Engineering, Computer Engineering, Computer Science, Electrical</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">429</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/PC%20Connection_3.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career & Internship Fair October 22, 2013 Majors, Thompson School Applied Science No Entry LevelInternships Whittemore Center PC Connection, Inc</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">430</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Goss%20International.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career and Internship Fair March 5, 2013 -- 12 America, Asia and Europe as well as a global sales and support network. Computer Science, Electrical</p> <div class="credits"> <p class="dwt_author">Pringle, James "Jamie"</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">431</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Liberty%20Mutual_0.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: No Career & Internship Fair October 22, 2013, Computer Engineering, Computer Science, Economics, Liberal Arts Majors, Math & Statistics Yes Entry Level</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">432</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Thermofisher.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: Unsure Career & Internship Fair October 22, 2013 -- 12:00-4:00pm Yes Sales, Finance, Customer Service, IT, Quality, Lab Science Thermo Fisher Scientific</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">433</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Safran%20Aerospace%20Composites.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description in engineering design process and materials science Strong written and oral communication skills Must be able & Internship Fair October 22, 2013 -- 12:00-4:00pm Yes Engineer Level I Safran is a world-class manufacturer</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">434</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.unh.edu/uacc/sites/unh.edu.uacc/files/Akumina.pdf"> <span id="translatedtitle">Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Company: Industry: Website: Majors: Offered: Offered: <span class="hlt">Position(s</span>): <span class="hlt">Position(s</span>): Description: Description: Paid/Unpaid: When: Hire International Students: Unsure Career & Internship Fair October 22, 2013 and on-going marketing program support. Computer Engineering, Computer Science No Entry Level</p> <div class="credits"> <p class="dwt_author">New Hampshire, University of</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">435</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54889117"> <span id="translatedtitle">Field Emission Current and Electrical Breakdown by a <span class="hlt">Pointed</span> Cathode Coated with Carbon-Nano-Tube</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Feature of field emission current and electrical breakdown was experimentally investigated for very short gap in the range of 0.1mum to 3mum between a <span class="hlt">pointed</span> cathode coated with Carbon-Nano-Tube (CNT) and a plane anode in vacuum environment. The experimental setup, which consists of the CNT coated cathode, the stainless steel anode and the <span class="hlt">precise</span> <span class="hlt">positioning</span> mechanisms actuated by piezoelectric devices,</p> <div class="credits"> <p class="dwt_author">Yoshinori Hirata; Masayoshi Teramoto; Mizue Mizoshiri; Ukyo Ikeda; Takayoshi Ohji; Kimihiro Ozaki</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">436</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014PhRvL.113m3902S"> <span id="translatedtitle">Optimal <span class="hlt">Point</span> Spread Function Design for 3D Imaging</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">To extract from an image of a single nanoscale object maximum physical information about its <span class="hlt">position</span>, we propose and demonstrate a framework for pupil-plane modulation for 3D imaging applications requiring <span class="hlt">precise</span> localization, including single-particle tracking and superresolution microscopy. The method is based on maximizing the information content of the system, by formulating and solving the appropriate optimization problem—finding the pupil-plane phase pattern that would yield a <span class="hlt">point</span> spread function (PSF) with optimal Fisher information properties. We use our method to generate and experimentally demonstrate two example PSFs: one optimized for 3D localization <span class="hlt">precision</span> over a 3 ?m depth of field, and another with an unprecedented 5 ?m depth of field, both designed to perform under physically common conditions of high background signals.</p> <div class="credits"> <p class="dwt_author">Shechtman, Yoav; Sahl, Steffen J.; Backer, Adam S.; Moerner, W. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">437</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/25302889"> <span id="translatedtitle">Optimal <span class="hlt">Point</span> Spread Function Design for 3D Imaging.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">To extract from an image of a single nanoscale object maximum physical information about its <span class="hlt">position</span>, we propose and demonstrate a framework for pupil-plane modulation for 3D imaging applications requiring <span class="hlt">precise</span> localization, including single-particle tracking and superresolution microscopy. The method is based on maximizing the information content of the system, by formulating and solving the appropriate optimization problem-finding the pupil-plane phase pattern that would yield a <span class="hlt">point</span> spread function (PSF) with optimal Fisher information properties. We use our method to generate and experimentally demonstrate two example PSFs: one optimized for 3D localization <span class="hlt">precision</span> over a 3???m depth of field, and another with an unprecedented 5???m depth of field, both designed to perform under physically common conditions of high background signals. PMID:25302889</p> <div class="credits"> <p class="dwt_author">Shechtman, Yoav; Sahl, Steffen J; Backer, Adam S; Moerner, W E</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-09-26</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">438</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=PRF&pg=2&id=EJ120901"> <span id="translatedtitle">Watch the Children: <span class="hlt">Precision</span> Referring</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">The <span class="hlt">Precision</span> Referral Form (PRF) is described as a quick, accurate and easy instrument that enables teachers to communicate learning and behavior problems of students to resource or ancillary personnel and to pinpoint students' behaviors. (GW)</p> <div class="credits"> <p class="dwt_author">Hiltbrunner, Curtis L.; Vasa, Stanley F.</p> <p class="dwt_publisher"></p> <p class="publishDate">1974-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">439</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.cancer.gov/cancertopics/treatment/types-of-treatment/targeted-therapy"> <span id="translatedtitle"><span class="hlt">Precision</span> Medicine and Targeted Therapy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.cancer.gov">Cancer.gov</a></p> <p class="result-summary">Information about the role that targeted therapies play in <span class="hlt">precision</span> medicine. Includes how targeted therapies work against cancer, who receives targeted therapies, common side effects, and what to expect when having targeted therapies.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">440</div> <div class="resultBody element"> <p cla