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1

Swarm intelligence for atmospheric compensation in free space optical communication-Modified shuffled frog leaping algorithm  

NASA Astrophysics Data System (ADS)

A conventional adaptive optics (AO) system is widely used to compensate atmospheric turbulence in free space optical (FSO) communication systems, but wavefront measurements based on phase-conjugation principle are not desired under strong scintillation circumstances. In this study we propose a novel swarm intelligence optimization algorithm, which is called modified shuffled frog leaping algorithm (MSFL), to compensate the wavefront aberration. Simulation and experiments results show that MSFL algorithm performs well in the atmospheric compensation and it can increase the coupling efficiency in receiver terminal and significantly improve the performance of the FSO communication systems.

Li, Zhaokun; Cao, Jingtai; Zhao, Xiaohui; Liu, Wei

2015-03-01

2

Atmospheric compensation in free space optical communication with simulated annealing algorithm  

NASA Astrophysics Data System (ADS)

As we know that the conventional adaptive optics (AO) systems can compensate atmospheric turbulence in free space optical (FSO) communication system. Since in strong scintillation conditions, wave-front measurements based on phase-conjugation principle are undesired. A novel global optimization simulated annealing (SA) algorithm is proposed in this paper to compensate wave-front aberration. With global optimization characteristics, SA algorithm is better than stochastic parallel gradient descent (SPGD) and other algorithms that already exist. Related simulations are conducted and the results show that the SA algorithm can significantly improve performance in FSO communication system and is better than SPGD algorithm with the increase of coupling efficiency.

Li, Zhaokun; Cao, Jingtai; Zhao, Xiaohui; Liu, Wei

2015-03-01

3

Implementation and performance of stochastic parallel gradient descent algorithm for atmospheric turbulence compensation  

NASA Astrophysics Data System (ADS)

IERUS Technologies, Inc. and the University of Alabama in Huntsville have partnered to perform characterization and development of algorithms and hardware for adaptive optics. To date the algorithm work has focused on implementation of the stochastic parallel gradient descent (SPGD) algorithm. SPGD is a metric-based approach in which a scalar metric is optimized by taking random perturbative steps for many actuators simultaneously. This approach scales to systems with a large number of actuators while maintaining bandwidth, while conventional methods are negatively impacted by the very large matrix multiplications that are required. The metric approach enables the use of higher speed sensors with fewer (or even a single) sensing element(s), enabling a higher control bandwidth. Furthermore, the SPGD algorithm is model-free, and thus is not strongly impacted by the presence of nonlinearities which degrade the performance of conventional phase reconstruction methods. Finally, for high energy laser applications, SPGD can be performed using the primary laser beam without the need for an additional beacon laser. The conventional SPGD algorithm was modified to use an adaptive gain to improve convergence while maintaining low steady state error. Results from laboratory experiments using phase plates as atmosphere surrogates will be presented, demonstrating areas in which the adaptive gain yields better performance and areas which require further investigation.

Finney, Greg A.; Persons, Christopher M.; Henning, Stephan; Hazen, Jessie; Whitley, Daniel

2014-06-01

4

A spectral climatology for atmospheric compensation  

NASA Astrophysics Data System (ADS)

Most Earth observation hyperspectral imagery (HSI) detection and identification algorithms depend critically upon a robust atmospheric compensation capability to correct for the effects of the atmosphere on the radiance signal. Atmospheric compensation methods typically perform optimally when ancillary ground truth data are available, e.g., high fidelity in situ radiometric observations or atmospheric profile measurements. When ground truth is incomplete or not available, additional assumptions must be made to perform the compensation. Meteorological climatologies are available to provide climatological norms for input into the radiative transfer models; however no such climatologies exist for empirical methods. The success of atmospheric compensation methods such as the empirical line method suggests that remotely sensed HSI scenes contain comprehensive sets of atmospheric state information within the spectral data itself. It is argued that large collections of empirically-derived atmospheric coefficients collected over a range of climatic and atmospheric conditions comprise a resource that can be applied to prospective atmospheric compensation problems. This paper introduces a new climatological approach to atmospheric compensation in which empirically derived spectral information, rather than sensible atmospheric state variables, is the fundamental datum. An experimental archive of airborne HSI data is mined for representative atmospheric compensation coefficients, which are assembled in a scientific database of spectral and sensible atmospheric observations. We present the empirical techniques for extracting the coefficients, the modeling methods used to standardize the coefficients across varying collection and illumination geometries, and the resulting comparisons of adjusted coefficients. Preliminary results comparing normalized coefficients from representative scenes across several distinct environments are presented, along with a discussion of the potential benefits, shortfalls and future work to fully develop the new technique.

Powell, John H.; Resmini, Ronald G.

2014-06-01

5

Compensated algorithms in floating point arithmetic  

E-print Network

Compensated algorithms in floating point arithmetic: accuracy, validation, performances. Nicolas ´Equipe DALI N. Louvet (Universit´e de Perpignan) Nicolas Louvet ­ Compensated algorithms in floating of errors when computing the solution of a scientific problem in floating point arithmetic: mathematical

Louvet, Nicolas

6

Assimilation of nontraditional datasets to improve atmospheric compensation  

NASA Astrophysics Data System (ADS)

Detection and characterization of space objects require the capability to derive physical properties such as brightness temperature and reflectance. These quantities, together with trajectory and position, are often used to correlate an object from a catalogue of known characteristics. However, retrieval of these physical quantities can be hampered by the radiative obscuration of the atmosphere. Atmospheric compensation must therefore be applied to remove the radiative signature of the atmosphere from electro-optical (EO) collections and enable object characterization. The JHU/APL Atmospheric Compensation System (ACS) was designed to perform atmospheric compensation for long, slant-range paths at wavelengths from the visible to infrared. Atmospheric compensation is critically important for airand ground-based sensors collecting at low elevations near the Earth's limb. It can be demonstrated that undetected thin, sub-visual cirrus clouds in the line of sight (LOS) can significantly alter retrieved target properties (temperature, irradiance). The ACS algorithm employs non-traditional cirrus datasets and slant-range atmospheric profiles to estimate and remove atmospheric radiative effects from EO/IR collections. Results are presented for a NASA-sponsored collection in the near-IR (NIR) during hypersonic reentry of the Space Shuttle during STS-132.

Kelly, Michael A.; Osei-Wusu, Kwame; Spisz, Thomas S.; Strong, Shadrian; Setters, Nathan; Gibson, David M.

2012-06-01

7

Atmospheric Compensation for Uplink Arrays via Radiometry  

NASA Technical Reports Server (NTRS)

Uplink arrays for communications applications are gaining increased visibility within the NASA and military community due to the enhanced flexibility and reliability they provide. When compared with the conventional large, single aperture antennas currently comprising the Deep Space Network (DSN), for example, smaller aperture antenna arrays have the benefits of providing fault tolerance (reduced single-point failure), reduced maintenance cost, and enhanced capabilities such as electronic beam-steering and multi-beam operation. However, signal combining of antenna array elements spaced many wavelengths apart becomes problematic due to the inherent instability of earth's turbulent atmosphere, particularly at the frequencies of interest to the DSN (i.e., Ka-band). Degradation in the power combining of the individual elements comprising the array arises due to uncorrelated phase errors introduced as the signals propagate through the troposphere. It is well known that the fundamental source of this error is due to the inhomogeneous distribution of water vapor in the atmosphere [1]. Several techniques have been proposed to circumvent this issue, including the use of phase calibration towers and a moon bounce to generate a feedback loop which would provide a means of intermittent calibration of the system phase errors (thermal drifts, atmosphere) [2,3]. However, these techniques require repositioning of the antenna elements to perform this operation which ultimately results in reduced system availability. And, though they are sufficient for compensating for slow varying phase drifts, they are insufficient to compensate for faster varying phase errors, such as those introduced by the atmosphere. In this paper, preliminary radiometry and interferometry measurements collected by the NASA Glenn Research Center are analyzed and indicate that the use of optimized water vapor radiometers as a feedback system in a communications platform could provide the necessary atmospheric compensation technique to enhance the beamforming of uplink arrays.

Nessel, James A.; Acosta, Roberto J.

2010-01-01

8

A relational database management system for atmospheric compensation research  

Microsoft Academic Search

Atmospheric compensation is a key step in the processing of most remotely sensed Earth images, but is particularly important in Hyperspectral Imagery (HSI) analysis. The state of atmospheric sensible variables at the time of the image is a key driver of atmospheric path radiance and transmissivity effects. A thorough assessment of the state of the atmosphere is rarely conducted in

John Powell; Gautami Erukulla; Mohamad Buhisi; Balendran Velauthapillai

2011-01-01

9

A Novel Motion Compensation Algorithm for Acoustic Radiation Force Elastography  

PubMed Central

A novel method of physiological motion compensation for use with radiation force elasticity imaging has been developed. The method utilizes a priori information from finite element method models of the response of soft tissue to impulsive radiation force to isolate physiological motion artifacts from radiation force-induced displacement fields. The new algorithm is evaluated in a series of clinically realistic imaging scenarios, and its performance is compared to that achieved with previously described motion compensation algorithms. Though not without limitations, the new model-based motion compensation algorithm performs favorably in many circumstances and may be a logical choice for use with in vivo abdominal imaging. PMID:18519218

Hsu, Stephen J.; Trahey, Gregg E.

2009-01-01

10

KALMAN FILTER WITH PHASE SPECTRUM COMPENSATION ALGORITHM FOR SPEECH ENHANCEMENT  

E-print Network

KALMAN FILTER WITH PHASE SPECTRUM COMPENSATION ALGORITHM FOR SPEECH ENHANCEMENT Stephen So, Kamil K with a recent speech enhancement technique, called the phase spectrum compen- sation procedure, or PSC. More-- Kalman filter, phase spectrum compensation (PSC), speech enhancement 1. INTRODUCTION The Kalman filter

11

Bjerknes Compensation at High Northern Latitudes: The Ocean Forcing the Atmosphere  

E-print Network

Bjerknes Compensation at High Northern Latitudes: The Ocean Forcing the Atmosphere E. VAN DER for Bjerknes compensation of heat transport variations through the atmosphere and ocean on decadal time scales are investigated, using data output from a preindustrial control run of the Third Hadley Centre Coupled Ocean­Atmosphere

Drijfhout, Sybren

12

Application of Least Mean Square Algorithms to Spacecraft Vibration Compensation  

NASA Technical Reports Server (NTRS)

This paper describes the application of the Least Mean Square (LMS) algorithm in tandem with the Filtered-X Least Mean Square algorithm for controlling a science instrument's line-of-sight pointing. Pointing error is caused by a periodic disturbance and spacecraft vibration. A least mean square algorithm is used on-orbit to produce the transfer function between the instrument's servo-mechanism and error sensor. The result is a set of adaptive transversal filter weights tuned to the transfer function. The Filtered-X LMS algorithm, which is an extension of the LMS, tunes a set of transversal filter weights to the transfer function between the disturbance source and the servo-mechanism's actuation signal. The servo-mechanism's resulting actuation counters the disturbance response and thus maintains accurate science instrumental pointing. A simulation model of the Upper Atmosphere Research Satellite is used to demonstrate the algorithms.

Woodard , Stanley E.; Nagchaudhuri, Abhijit

1998-01-01

13

Retrieval of atmospheric properties from hyper and multispectral imagery with the FLAASH atmospheric correction algorithm  

NASA Astrophysics Data System (ADS)

Atmospheric Correction Algorithms (ACAs) are used in applications of remotely sensed Hyperspectral and Multispectral Imagery (HSI/MSI) to correct for atmospheric effects on measurements acquired by air and space-borne systems. The Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) algorithm is a forward-model based ACA created for HSI and MSI instruments which operate in the visible through shortwave infrared (Vis-SWIR) spectral regime. Designed as a general-purpose, physics-based code for inverting at-sensor radiance measurements into surface reflectance, FLAASH provides a collection of spectral analysis and atmospheric retrieval methods including: a per-pixel vertical water vapor column estimate, determination of aerosol optical depth, estimation of scattering for compensation of adjacency effects, detection/characterization of clouds, and smoothing of spectral structure resulting from an imperfect atmospheric correction. To further improve the accuracy of the atmospheric correction process, FLAASH will also detect and compensate for sensor-introduced artifacts such as optical smile and wavelength mis-calibration. FLAASH relies on the MODTRANTM radiative transfer (RT) code as the physical basis behind its mathematical formulation, and has been developed in parallel with upgrades to MODTRAN in order to take advantage of the latest improvements in speed and accuracy. For example, the rapid, high fidelity multiple scattering (MS) option available in MODTRAN4 can greatly improve the accuracy of atmospheric retrievals over the 2-stream approximation. In this paper, advanced features available in FLAASH are described, including the principles and methods used to derive atmospheric parameters from HSI and MSI data. Results are presented from processing of Hyperion, AVIRIS, and LANDSAT data.

Perkins, Timothy; Adler-Golden, Steven; Matthew, Michael; Berk, Alexander; Anderson, Gail; Gardner, James; Felde, Gerald

2005-10-01

14

Atmospheric correction algorithm with multidirectional POLDER data  

NASA Astrophysics Data System (ADS)

The atmospheric correction in ocean color remote sensing ins the most significant technique to retrieve the water leaving radiances, which are less than 10 percent of the satellite radiances, and its main errors are occurred by the estimation errors of the aerosol property and quantity which are highly variable in both space and time. In this study, our main purpose is to develop the advanced atmospheric correction method by using multi-viewing satellite data. POLDER onboard ADEOS can acquire multi-direction reflectance up to 14 viewing angles. In order to evaluate the validity of the multi-angle algorithm, we tired to test the algorithm with POLDER data. Results of comparisons with OCTS algorithm show that this algorithm with 3 or 4 angles POLDER data is available to estimate the aerosol properties because it is not affected form the errors depend on the band ratio.

Mitomi, Yasushi; Fukushima, Hajime; Takamura, Tamio

2002-01-01

15

High-bandwidth long-stroke segmented mirror for atmospheric compensation  

Microsoft Academic Search

Segmented Adaptive Optic Mirrors have been developed, fabricated, and demonstrated in real time atmospheric compensation systems. Until recently, most Segmented Adaptive Optic Mirrors have been designed for single wavelength applications and have not required more than 1.5 (mu) of surface motion since absolute phasing of the surface is not required for very narrow bandwidth compensation. Requirements for astronomical and imaging

William G. Hulburd; Todd K. Barrett; E. L. Cuellar; David G. Sandler

1992-01-01

16

Springback compensation algorithm for tool design in creep age forming of large aluminum alloy plate  

NASA Astrophysics Data System (ADS)

The creep unified constitutive equations, which was built based on the age forming mechanism of aluminum alloy, was integrated with the commercial finite element analysis software MSC.MARC via the user defined subroutine, CREEP, and the creep age forming process simulations for7055 aluminum alloy plate parts were conducted. Then the springback of the workpiece after forming was calculated by ATOS Professional Software. Based on the combination between simulation results and calculation of springback by ATOS for the formed plate, a new weighted springback compensation algorithm for tool surface modification was developed. The compensate effects between the new algorithm and other overall compensation algorithms on the tool surface are compared. The results show that, the maximal forming error of the workpiece was reduced to below 0.2mm after 5 times compensations with the new weighted algorithm, while error rebound phenomenon occurred and the maximal forming error cannot be reduced to 0.3mm even after 6 times compensations with fixed or variable compensation coefficient, which are based on the overall compensation algorithm.

Xu, Xiaolong; Zhan, Lihua; Huang, Minghui

2013-12-01

17

A Comprehensive Study of Three Delay Compensation Algorithms for Flight Simulators  

NASA Technical Reports Server (NTRS)

This paper summarizes a comprehensive study of three predictors used for compensating the transport delay in a flight simulator; The McFarland, Adaptive and State Space Predictors. The paper presents proof that the stochastic approximation algorithm can achieve the best compensation among all four adaptive predictors, and intensively investigates the relationship between the state space predictor s compensation quality and its reference model. Piloted simulation tests show that the adaptive predictor and state space predictor can achieve better compensation of transport delay than the McFarland predictor.

Guo, Liwen; Cardullo, Frank M.; Houck, Jacob A.; Kelly, Lon C.; Wolters, Thomas E.

2005-01-01

18

Phase compensating algorithm investigation of real-time adaptive femtosecond pulse shaping  

NASA Astrophysics Data System (ADS)

Based on the real-time adaptive femtosecond pulse shaping system, the phase compensating algorithms which can effectively compensate the output shaping waveform distortions are investigated in detail. The simulated-annealing algorithm that can modify the output pulse temporal waveforms iteratively toward the target shapes using the second harmonic generating frequency resolved optical gating (SHG-FROG) measurement as feedback is proposed. Compared with the cross-correlation feedback measurement method, the output based on the SHG-FROG measurement method is better and the temporal chirp of the output pulse is compensated more effectively. Moreover the performance of the SHG-FROG measurement feedback algorithm is compared to other exemplary standard approaches such as the Genetic Algorithm based on the cross-correlation feedback measurement method, the result is much better.

Lou, Xin; Sun, Tie-ju; Duan, Fang-zhen; Yang, Xue-hua; Nie, Yong-ming

2013-09-01

19

Validation of atmospheric correction algorithm ATCOR  

NASA Astrophysics Data System (ADS)

Atmospheric correction of satellite images is necessary for many applications of remote sensing, i.e. computation of vegetation indices and biomass estimation. The largest uncertainty in atmospheric correction arises out of spatial and temporal variation of aerosol amount and type. Therefore validation of aerosol estimation is one important step in validation of atmospheric correction algorithms. Our ground-based measurements of aerosol-optical thickness spectra (AOT) were performed synchronously to overpasses of satellites Rapid-Eye and Landsat. Validation of aerosol retrieval by the widely used atmospheric correction tool ATCOR1,2 was then realized by comparison of AOT derived from satellite data with the ground-truths. Mean uncertainty is ?AOT550 ? 0.04, corresponding approximately to uncertainty in surface albedo of ?? ? 0.004. Generally, ATCOR-derived AOT values are mostly overestimated when compared to the ground-truth measurements. Very little differences are found between Rapid-Eye and Landsat sensors. Differences between using rural and maritime aerosols are negligible within the visible spectral range.

Pflug, Bringfried; Main-Knorn, Magdalena

2014-10-01

20

ANFIS-Based Compensation Algorithm for Current-Transformer Saturation Effects  

Microsoft Academic Search

This paper proposes an efficient compensation algorithm based on an adaptive network-based fuzzy inference system capable of converting a sampled current waveform that is distorted by current-transformer (CT) saturation to a compensated current waveform. Quick response time, no cumulative estimation error, desired sample-by-sample output, no dependency of CT parameters\\/characteristics and secondary burdens, and simplicity are some attractive features of the

Koksal Erenturk

2009-01-01

21

Improved Fault Classification in Series Compensated Transmission Line: Comparative Evaluation of Chebyshev Neural Network Training Algorithms.  

PubMed

This paper presents the Chebyshev neural network (ChNN) as an improved artificial intelligence technique for power system protection studies and examines the performances of two ChNN learning algorithms for fault classification of series compensated transmission line. The training algorithms are least-square Levenberg-Marquardt (LSLM) and recursive least-square algorithm with forgetting factor (RLSFF). The performances of these algorithms are assessed based on their generalization capability in relating the fault current parameters with an event of fault in the transmission line. The proposed algorithm is fast in response as it utilizes postfault samples of three phase currents measured at the relaying end corresponding to half-cycle duration only. After being trained with only a small part of the generated fault data, the algorithms have been tested over a large number of fault cases with wide variation of system and fault parameters. Based on the studies carried out in this paper, it has been found that although the RLSFF algorithm is faster for training the ChNN in the fault classification application for series compensated transmission lines, the LSLM algorithm has the best accuracy in testing. The results prove that the proposed ChNN-based method is accurate, fast, easy to design, and immune to the level of compensations. Thus, it is suitable for digital relaying applications. PMID:25314714

Vyas, Bhargav Y; Das, Biswarup; Maheshwari, Rudra Prakash

2014-10-13

22

Free breathing myocardial perfusion data sets for performance analysis of motion compensation algorithms  

PubMed Central

Background Perfusion quantification by using first-pass gadolinium-enhanced myocardial perfusion magnetic resonance imaging (MRI) has proved to be a reliable tool for the diagnosis of coronary artery disease that leads to reduced blood flow to the myocardium. The image series resulting from such acquisition usually exhibits a breathing motion that needs to be compensated for if a further automatic analysis of the perfusion is to be executed. Various algorithms have been presented to facilitate such a motion compensation, but the lack of publicly available data sets hinders a proper, reproducible comparison of these algorithms. Material Free breathing perfusion MRI series of ten patients considered clinically to have a stress perfusion defect were acquired; for each patient a rest and a stress study was executed. Manual segmentations of the left ventricle myocardium and the right-left ventricle insertion point are provided for all images in order to make a unified validation of the motion compensation algorithms and the perfusion analysis possible. In addition, all the scripts and the software required to run the experiments are provided alongside the data, and to enable interested parties to directly run the experiments themselves, the test bed is also provided as a virtual hard disk. Findings To illustrate the utility of the data set two motion compensation algorithms with publicly available implementations were applied to the data and earlier reported results about the performance of these algorithms could be confirmed. Conclusion The data repository alongside the evaluation test bed provides the option to reliably compare motion compensation algorithms for myocardial perfusion MRI. In addition, we encourage that researchers add their own annotations to the data set, either to provide inter-observer comparisons of segmentations, or to make other applications possible, for example, the validation of segmentation algorithms. PMID:25392734

2014-01-01

23

An NN-Based SRD Decomposition Algorithm and Its Application in Nonlinear Compensation  

PubMed Central

In this study, a neural network-based square root of descending (SRD) order decomposition algorithm for compensating for nonlinear data generated by sensors is presented. The study aims at exploring the optimized decomposition of data 1.00,0.00,0.00 and minimizing the computational complexity and memory space of the training process. A linear decomposition algorithm, which automatically finds the optimal decomposition of N subparts and reduces the training time to 1N and memory cost to 1N, has been implemented on nonlinear data obtained from an encoder. Particular focus is given to the theoretical access of estimating the numbers of hidden nodes and the precision of varying the decomposition method. Numerical experiments are designed to evaluate the effect of this algorithm. Moreover, a designed device for angular sensor calibration is presented. We conduct an experiment that samples the data of an encoder and compensates for the nonlinearity of the encoder to testify this novel algorithm. PMID:25232912

Yan, Honghang; Deng, Fang; Sun, Jian; Chen, Jie

2014-01-01

24

Validation and Error Metrics for the Atmospheric Compensation for a Landsat Land Surface Temperature Product  

NASA Astrophysics Data System (ADS)

An automated process for the atmospheric compensation for a Landsat land surface temperature product has been developed. Landsat data are very attractive for a global land surface temperature product because the spatial and temporal resolution and range of the imagery make them well matched to applications for the study of agriculture, the environment, weather, and climate among others. However, Landsat's single thermal band requires per-pixel atmospheric compensation and emissivity; this work focuses on the atmospheric compensation aspect of the process and will be integrated with ASTER derived emissivity data to output a land surface temperature product. For the same reasons Landsat is attractive, an automated atmospheric compensation technique is challenging; it requires atmospheric characterization over a large area and long time scale at an acceptable resolution. Using North American Regional Reanalysis (NARR) data, MODTRAN radiative transfer code, and a number of interpolation techniques, a tool has been developed to generate the necessary radiative transfer parameters at each pixel for any radiometrically calibrated North American Landsat scene in the archive. Initial validation of predicted temperatures using ground truth water temperatures from platforms and buoys verifies the fidelity of the process with good performance when the atmosphere is accurately characterized. However, performance is poorer when the composition of the atmosphere is not as well understood. Because of the desired automation and extent of the tool, we are limited in the availability of acceptable atmospheric profile data. The goal is to understand sources of error in order to predict and characterize the uncertainty in the retrieved temperatures. While the performance has been extensively tested using a number of NOAA buoys with bulk temperature measurements corrected to skin temperature, traditional error analysis is complicated by the atmospheric reanalysis, radiative transfer codes, bulk to skin temperature conversion, and lack of knowledge of atmospheric variations not captured by the reanalysis data, so current work focuses on developing and comparing different methods of error prediction. Characterizing errors in the input atmospheric profiles, regression techniques against current error values, and thresholds based on known atmospheric variables have all been considered. The goal is to utilize a hybrid approach to generate a confidence for each pixel in the final product that will provide the user with metrics that predict the expected performance with a range of confidence scores.

Cook, M. J.; Schott, J. R.

2013-12-01

25

Atmospheric compensation for WorldView-2 satellite and in-water component retrieval  

NASA Astrophysics Data System (ADS)

In the present work, the WorldView-2 (WV2) capability for retrieving Case 2 water components is analyzed. The WV2 sensor characteristics, such as a 11-bit quantization, 8 bands in the VNIR (visible and near infrared) region and high Signal-to-Noise Ratios (SNR) make WV2 potentially suitable for a retrieval process. In the Case 2 water problem, the sensor-reaching signal due to water is very small when compared to the signal due to the atmospheric eects. Therefore, adequate atmospheric compensation becomes an important rst step to accurately retrieve water parameters. The problem becomes more dicult when using multispectral imagery as there are typically only a handful of bands suitable for performing atmospheric compensation. In this work, we test atmospheric compensation techniques for the WV2 satellite, enabling it to be used for water constituent retrieval in both deep and shallow water. A look-up-table (LUT) methodology is implemented to retrieve the water parameters chlorophyll, suspended materials, colored dissolved organic matter, bathymetry, bottom type and water clarity for a simulated case study. The in-water radiative transfer code HydroLight is used to simulate re ectance data in this study while the MODTRAN code is used to simulate atmospheric eects. The resulting modeled sensor-reaching radiance data can be sampled to a WV2 sensor model to simulate WV2 image data. This data is used to test the proposed methodology. Finally, a sensitivity analysis is performed to evaluate how sensitive the constituent retrieval process is to adequate atmospheric compensation.

Concha, Javier A.; Gerace, Aaron D.

2012-06-01

26

Compensation algorithm for optical flow vectors based on image sequences of the spot  

Microsoft Academic Search

A key problem in the processing of image sequences is estimating the motion between video frames, often referred to as optical flow estimation. For the problem of the target spots loss in image sequences when aircraft's 3D attitude parameters is measured based on optical measurement, an effective optical flow vectors compensation algorithm from multi-frames image is proposed. First, the optical

Yuhua Zhao; Feng Yuan; Zhenliang Ding

2010-01-01

27

A Resistance Compensation Control Algorithm for a Cable-Driven Hand Exoskeleton for Motor Function  

E-print Network

A Resistance Compensation Control Algorithm for a Cable-Driven Hand Exoskeleton for Motor Function, hand exoskeleton 1 Introduction As we know, the motor capability of hand is crucial and important existing exoskeleton-type hand rehabilitation devices, the cable and sheath is utilized in mechanical

28

Optimization algorithm in adaptive PMD compensation in 10Gb/s optical communication system  

NASA Astrophysics Data System (ADS)

In this paper, the optimization algorithms are introduced in adaptive PMD compensation in 10Gb/s optical communication system. The PMD monitoring technique based on degree of polarization (DOP) is adopted. DOP can be a good indicator of PMD with monotonically deceasing of DOP as differential group delay (DGD) increasing. In order to use DOP as PMD monitoring feedback signal, it is required to emulate the state of DGD in the transmission circuitry. A PMD emulator is designed. A polarization controller (PC) is used in fiber multiplexer to adjust the polarization state of optical signal, and at the output of the fiber multiplexer a polarizer is used. After the feedback signal reach the control computer, the optimization program run to search the global optimization spot and through the PC to control the PMD. Several popular modern nonlinear optimization algorithms (Tabu Search, Simulated Annealing, Genetic Algorithm, Artificial Neural Networks, Ant Colony Optimization etc.) are discussed and the comparisons among them are made to choose the best optimization algorithm. Every algorithm has its advantage and disadvantage, but in this circs the Genetic Algorithm (GA) may be the best. It eliminates the worsen spots constantly and lets them have no chance to enter the circulation. So it has the quicker convergence velocity and less time. The PMD can be compensated in very few steps by using this algorithm. As a result, the maximum compensation ability of the one-stage PMD and two-stage PMD can be made in very short time, and the dynamic compensation time is no more than 10ms.

Diao, Cao; Li, Tangjun; Wang, Muguang; Gong, Xiangfeng

2005-02-01

29

PACKET FAIR SCHEDULING ALGORITHM BASED ON WEIGHTS DYNAMIC COMPENSATION  

Microsoft Academic Search

PFQ is approximation of GPS in packet switching networks and it can provide packet flows with QoS and fairness. Based on research\\u000a of fairness of GPS and details of WFQ and WF2Q, this paper implements CFQ algorithm with the idea of maintaining the proportional fairness as GPS. CFQ introduces the concept\\u000a of deflection ratio and uses it in computing of

Zhang Wei; Liu Yan-heng; Yu Xue-gang; Xie A-lian

30

TIGER: Development of Thermal Gradient Compensation Algorithms and Techniques  

NASA Technical Reports Server (NTRS)

In a wind tunnel facility, the direct measurement of forces and moments induced on the model are performed by a force measurement balance. The measurement balance is a precision-machined device that has strain gages at strategic locations to measure the strain (i.e., deformations) due to applied forces and moments. The strain gages convert the strain (and hence the applied force) to an electrical voltage that is measured by external instruments. To address the problem of thermal gradients on the force measurement balance NASA-LaRC has initiated a research program called TIGER - Thermally-Induced Gradients Effects Research. The ultimate goals of the TIGER program are to: (a) understand the physics of the thermally-induced strain and its subsequent impact on load measurements and (b) develop a robust thermal gradient compensation technique. This paper will discuss the impact of thermal gradients on force measurement balances, specific aspects of the TIGER program (the design of a special-purpose balance, data acquisition and data analysis challenges), and give an overall summary.

Hereford, James; Parker, Peter A.; Rhew, Ray D.

2004-01-01

31

Multilevel Algorithm for Atmospheric Data Assimilation  

NASA Technical Reports Server (NTRS)

A multiscale algorithm for the problem of optimal statistical interpolation of observed data has been developed. This problem includes the calculation of the vector of the 'analyzed' (best estimated) atmosphere flow field w(sup a) by the formula: w(sup a) = w(sup f) + P(sup f) H(sup T) y, where the quantity y is defined by the equation (H P(sup f) H(sup T) + R)y = w(sup o) - H w(sup f), using the given model forecast first guess w(sup f) and the vector of observations w(sup o); H is an interpolation operator from the regular grid to the observation network, P(sup f) is the forecast error covariance matrix, and R is the observation error covariance matrix. At this initial stage the case of univariate analysis of single level radiosonde height data is considered. The matrix R is assumed to be diagonal, and the matrix P(sup f) is assumed to be given by the formula P(sub ij)(sup f) = sigma(sub i)(sup f) mu(sub ij) sigma(sub j)(sub f), where mu(sub ij) is a smooth, decreasing function of the distance between the i-th and the j-th points. In this paper we describe a multiscale iterative process based on a multiresolution, simultaneous displacement technique and a localized variational calculation of iteration parameters.

Brandt, Achi; Zaslavsky, Leonid Yu.

1996-01-01

32

MTRC compensation in high-resolution ISAR imaging via improved polar format algorithm  

NASA Astrophysics Data System (ADS)

Migration through resolution cells (MTRC) is generated in high-resolution inverse synthetic aperture radar (ISAR) imaging. A MTRC compensation algorithm for high-resolution ISAR imaging based on improved polar format algorithm (PFA) is proposed in this paper. Firstly, in the situation that a rigid-body target stably flies, the initial value of the rotation angle and center of the target is obtained from the rotation of radar line of sight (RLOS) and high range resolution profile (HRRP). Then, the PFA is iteratively applied to the echo data to search the optimization solution based on minimum entropy criterion. The procedure starts with the estimated initial rotation angle and center, and terminated when the entropy of the compensated ISAR image is minimized. To reduce the computational load, the 2-D iterative search is divided into two 1-D search. One is carried along the rotation angle and the other one is carried along rotation center. Each of the 1-D searches is realized by using of the golden section search method. The accurate rotation angle and center can be obtained when the iterative search terminates. Finally, apply the PFA to compensate the MTRC by the use of the obtained optimized rotation angle and center. After MTRC compensation, the ISAR image can be best focused. Simulated and real data demonstrate the effectiveness and robustness of the proposed algorithm.

Liu, Yang; Li, Hao; Li, Na; Xu, Shiyou; Chen, Zengping

2014-10-01

33

A fast atmospheric correction algorithm applied to Landsat TM images  

Microsoft Academic Search

A fast atmospheric correction algorithm for the reflective bands (0.4-2.5 microns) of remote sensing instruments is presented. It proceeds in two steps: calculation of the ground reflectance of each pixel based on precomputed planetary albedo functions for different standard atmospheres, aerosol types and optical depths, or actual atmospheric measurement data, and approximate correction of the adjacency effect by taking into

Rudolf Richter

1990-01-01

34

Performance-metric driven atmospheric compensation for robust free-space laser communication  

Microsoft Academic Search

Laser Communication (LaserCom) offers some profound advantages over RF-based systems, such as higher-bandwidth, lower power consumption, and lower probability of intercept. However, the effect of turbulence on laser propagation is a significant challenge to current electro-optical systems. While atmospheric compensation techniques in space object imaging and high-energy laser weapons have been thoroughly investigated, optimizing these techniques for LaserCom has not

Peter N. Crabtree

2006-01-01

35

Iterative reconstruction methods in atmospheric tomography: FEWHA, Kaczmarz and Gradient-based algorithm  

NASA Astrophysics Data System (ADS)

The problem of atmospheric tomography arises in ground-based telescope imaging with adaptive optics (AO), where one aims to compensate in real-time for the rapidly changing optical distortions in the atmosphere. Many of these systems depend on a sufficient reconstruction of the turbulence profiles in order to obtain a good correction. Due to steadily growing telescope sizes, there is a strong increase in the computational load for atmospheric reconstruction with current methods, first and foremost the MVM. In this paper we present and compare three novel iterative reconstruction methods. The first iterative approach is the Finite Element- Wavelet Hybrid Algorithm (FEWHA), which combines wavelet-based techniques and conjugate gradient schemes to efficiently and accurately tackle the problem of atmospheric reconstruction. The method is extremely fast, highly flexible and yields superior quality. Another novel iterative reconstruction algorithm is the three step approach which decouples the problem in the reconstruction of the incoming wavefronts, the reconstruction of the turbulent layers (atmospheric tomography) and the computation of the best mirror correction (fitting step). For the atmospheric tomography problem within the three step approach, the Kaczmarz algorithm and the Gradient-based method have been developed. We present a detailed comparison of our reconstructors both in terms of quality and speed performance in the context of a Multi-Object Adaptive Optics (MOAO) system for the E-ELT setting on OCTOPUS, the ESO end-to-end simulation tool.

Ramlau, R.; Saxenhuber, D.; Yudytskiy, M.

2014-07-01

36

Performance-metric driven atmospheric compensation for robust free-space laser communication  

NASA Astrophysics Data System (ADS)

Laser Communication (LaserCom) offers some profound advantages over RF-based systems, such as higher-bandwidth, lower power consumption, and lower probability of intercept. However, the effect of turbulence on laser propagation is a significant challenge to current electro-optical systems. While atmospheric compensation techniques in space object imaging and high-energy laser weapons have been thoroughly investigated, optimizing these techniques for LaserCom has not been examined to the same degree. This research investigates performance-metric driven atmospheric compensation techniques to improve reliability of free-space LaserCom systems. Several receiver-based techniques were developed and analyzed while considering constraints relevant to tactical airborne platforms. First, wavefront control techniques were considered. In a moderate range air-to-air scenario, focal plane image breakup is identified as the dominant failure mechanism causing deep fades. This led to investigation of peak intensity tracking, which reduces fade probability by greater than 50% over conventional centroid trackers and Adaptive Optics (AO) systems for scenarios studied. Second, atmospheric compensation requirements were examined based on deep fade phenomenology. Fades are classified based on complexity of the required compensation technique. For compensation techniques studied, regions of superior performance, in terms of fade probability, are identified. Peak tracking is shown to outperform AO for thresholds below approximately 4% of the unaberrated intensity. Furthermore, the boundary between superior performance regions is nearly invariant to turbulence strength. This boundary invariance simplifies operation of a composite system which is able to adaptively select compensation methodology in near real-time. An adaptive binary decision threshold is the third major focus of this research. Analytic results show that an adaptive threshold provides a bit-error rate improvement of up to 1.60 orders of magnitude (33-fold decrease) for a 10 Gbps link, and up to 0.56 orders of magnitude (3.6-fold decrease) for a 10 Mbps link. Adaptive thresholding yields improved performance without the additional cost, weight, and/or complexity of increasing source power, incorporating wavefront control at receiver, or incorporating AO at the transmitter.

Crabtree, Peter N.

37

Compensation algorithm for optical flow vectors based on image sequences of the spot  

NASA Astrophysics Data System (ADS)

A key problem in the processing of image sequences is estimating the motion between video frames, often referred to as optical flow estimation. For the problem of the target spots loss in image sequences when aircraft's 3D attitude parameters is measured based on optical measurement, an effective optical flow vectors compensation algorithm from multi-frames image is proposed. First, the optical flow vectors between frames of spot target image sequences are calculated by Lucas-Kanade algorithm, and then choose the optical flow vectors nearby the images of lost spot target. The chosen vectors are used for estimating spot image. The compensation model of optical flow vectors is set. Then, the lost spot target center is got by using inverse distance weighted averaging and the weight-value is the difference of the frame count between real image and estimated image. By experiments analysis, the proper calculating scope of this arithmetic under the expected precision is determined. This algorithm compensates the calculation errors caused by the lost target in image sequences efficiently.

Zhao, Yuhua; Yuan, Feng; Ding, Zhenliang

2010-10-01

38

Comparision of algorithms for incoming atmospheric long-wave radiation  

Technology Transfer Automated Retrieval System (TEKTRAN)

While numerous algorithms exist for predicting incident atmospheric long-wave radiation under clear (Lclr) and cloudy skies, only a handful of comparisons have been published to assess the accuracy of the different algorithms. Virtually no comparisons have been made for both clear and cloudy skies ...

39

MTF compensation algorithm based on blind deconvolution for high-resolution remote sensing satellite  

NASA Astrophysics Data System (ADS)

In high resolution remote sensing satellite imaging system, image restoration is an important step to visualize ne details and mitigate the noise. The raw image data often presents poor imaging quality due to various reasons and Point Spread Function (PSF) measures such blurriness characteristic of the image using point source. Satellite image from Korea Multi-purpose Satellite 2 (KOMPSAT-2) also requires Modular Transfer Function (MTF) compensation process to achieve more realistic image which entails removing ringing artifacts at the edges and restraining excess use of denoising eect in order to keep it more realistic. This paper focuses on the deconvolution of KOMPSAT-2 image utilizing PSF attained from Korea Aerospace Research Institute compared to deconvolution with the estimated PSF blur kernel. The deconvolution algorithm considered are Richard-Lucy, Damped Richard-Lucy, Bilateral Richard-Lucy and Sparse Prior deconvolution algorithms.

Lee, Jihye; Chun, Joohwan; Lee, Donghwan

2012-05-01

40

Algorithm for Atmospheric Corrections of Aircraft and Satellite Imagery  

NASA Technical Reports Server (NTRS)

A simple and fast atmospheric correction algorithm is described which is used to correct radiances of scattered sunlight measured by aircraft and/or satellite above a uniform surface. The atmospheric effect, the basic equations, a description of the computational procedure, and a sensitivity study are discussed. The program is designed to take the measured radiances, view and illumination directions, and the aerosol and gaseous absorption optical thickness to compute the radiance just above the surface, the irradiance on the surface, and surface reflectance. Alternatively, the program will compute the upward radiance at a specific altitude for a given surface reflectance, view and illumination directions, and aerosol and gaseous absorption optical thickness. The algorithm can be applied for any view and illumination directions and any wavelength in the range 0.48 micron to 2.2 micron. The relation between the measured radiance and surface reflectance, which is expressed as a function of atmospheric properties and measurement geometry, is computed using a radiative transfer routine. The results of the computations are presented in a table which forms the basis of the correction algorithm. The algorithm can be used for atmospheric corrections in the presence of a rural aerosol. The sensitivity of the derived surface reflectance to uncertainties in the model and input data is discussed.

Fraser, Robert S.; Kaufman, Yoram J.; Ferrare, Richard A.; Mattoo, Shana

1989-01-01

41

A compact algorithm for three-phase three-wire system reactive power compensation and load balancing  

SciTech Connect

A compact control algorithm for reactive power compensation and load balancing with the static var compensator (SVC) in three-phase three-wire systems is developed in this paper. Each phase susceptance of the SVC can be obtained from a very simple function of voltage and power signals which are measured by a three-phase voltage transducer and two single-phase active and reactive power (P-Q) transducers at the load bus. The calculation of compensation susceptances is based on the criterion of a unity power factor and zero sequence currents after compensation. A simulation is made, as the first stage, to show the validity of the proposed compensation algorithm. Then, a laboratory size microcomputer-based SVC, which consists of thyristor-controlled reactors (TCRs) and fixed capacitors (FCs), is designed and implemented. Simulation and experiment results show that the algorithm is very suitable for on-line control of the SVC which is designed for phase balancing and power factor correction.

Lee, S.Y. [Kao Yuan Junior Coll. of Technology and Commerce, Kaohsiung (Taiwan, Province of China). Dept. of Electrical Engineering; Chang, W.N.; Wu, C.J. [National Taiwan Inst. of Tech., Peitow-Taipei (Taiwan, Province of China). Dept. of Electrical Engineering

1995-12-31

42

Application of genetic algorithm in atmospheric carbon dioxide concentration retrieval  

NASA Astrophysics Data System (ADS)

This paper introduces the basic theory and method of carbon dioxide (CO2) retrieval. The key step is to search for the optimal solution and the random search algorithm Genetic Algorithm (GA) which can effectively avoid the local optimization. We first investigate the basic principles of GA in CO2 retrieval and then design the corresponding encoding and decoding methods as well as the fitness function. This newly-developed GA is further applied to retrieve the atmospheric CO2 concentration using Atmospheric Infrared Sounder (AIRS) observations from January 2006 to December 2008 centered at 20N, 144E. Compared to the aircraft measurements, the GA retrieval yields the small root mean square error of 1.13 ppmv and reproduces good results with the observed seasonal cycle.

Li, Jingyao; Shi, Runhe; Gao, Wei

2013-09-01

43

Control algorithms for aerobraking in the Martian atmosphere  

NASA Technical Reports Server (NTRS)

The Analytic Predictor Corrector (APC) and Energy Controller (EC) atmospheric guidance concepts were adapted to control an interplanetary vehicle aerobraking in the Martian atmosphere. Changes are made to the APC to improve its robustness to density variations. These changes include adaptation of a new exit phase algorithm, an adaptive transition velocity to initiate the exit phase, refinement of the reference dynamic pressure calculation and two improved density estimation techniques. The modified controller with the hybrid density estimation technique is called the Mars Hybrid Predictor Corrector (MHPC), while the modified controller with a polynomial density estimator is called the Mars Predictor Corrector (MPC). A Lyapunov Steepest Descent Controller (LSDC) is adapted to control the vehicle. The LSDC lacked robustness, so a Lyapunov tracking exit phase algorithm is developed to guide the vehicle along a reference trajectory. This algorithm, when using the hybrid density estimation technique to define the reference path, is called the Lyapunov Hybrid Tracking Controller (LHTC). With the polynomial density estimator used to define the reference trajectory, the algorithm is called the Lyapunov Tracking Controller (LTC). These four new controllers are tested using a six degree of freedom computer simulation to evaluate their robustness. The MHPC, MPC, LHTC, and LTC show dramatic improvements in robustness over the APC and EC.

Ward, Donald T.; Shipley, Buford W., Jr.

1991-01-01

44

Advanced Control Algorithms for Compensating the Phase Distortion Due to Transport Delay in Human-Machine Systems  

NASA Technical Reports Server (NTRS)

The desire to create more complex visual scenes in modern flight simulators outpaces recent increases in processor speed. As a result, simulation transport delay remains a problem. New approaches for compensating the transport delay in a flight simulator have been developed and are presented in this report. The lead/lag filter, the McFarland compensator and the Sobiski/Cardullo state space filter are three prominent compensators. The lead/lag filter provides some phase lead, while introducing significant gain distortion in the same frequency interval. The McFarland predictor can compensate for much longer delay and cause smaller gain error in low frequencies than the lead/lag filter, but the gain distortion beyond the design frequency interval is still significant, and it also causes large spikes in prediction. Though, theoretically, the Sobiski/Cardullo predictor, a state space filter, can compensate the longest delay with the least gain distortion among the three, it has remained in laboratory use due to several limitations. The first novel compensator is an adaptive predictor that makes use of the Kalman filter algorithm in a unique manner. In this manner the predictor can accurately provide the desired amount of prediction, while significantly reducing the large spikes caused by the McFarland predictor. Among several simplified online adaptive predictors, this report illustrates mathematically why the stochastic approximation algorithm achieves the best compensation results. A second novel approach employed a reference aircraft dynamics model to implement a state space predictor on a flight simulator. The practical implementation formed the filter state vector from the operator s control input and the aircraft states. The relationship between the reference model and the compensator performance was investigated in great detail, and the best performing reference model was selected for implementation in the final tests. Theoretical analyses of data from offline simulations with time delay compensation show that both novel predictors effectively suppress the large spikes caused by the McFarland compensator. The phase errors of the three predictors are not significant. The adaptive predictor yields greater gain errors than the McFarland predictor for short delays (96 and 138 ms), but shows smaller errors for long delays (186 and 282 ms). The advantage of the adaptive predictor becomes more obvious for a longer time delay. Conversely, the state space predictor results in substantially smaller gain error than the other two predictors for all four delay cases.

Guo, Liwen; Cardullo, Frank M.; Kelly, Lon C.

2007-01-01

45

Compensation for the effects of time delay in a helmet-mounted display: perceptual adaptation versus algorithmic prediction  

NASA Astrophysics Data System (ADS)

Virtual environment technologies, such as helmet-mounted displays (HMDs), are challenged by problems involving time delay--the time between an input to a system, and its corresponding output. An experiment was conducted to evaluate two methods of time delay compensation--algorithmic prediction and perceptual adaptation--during a time-delayed, head- slaved tracking task using an HMD. Predictive algorithms attempt to compensate for time delays by predicting future head position in order to update images effectively in the HMD. Perceptual adaptation refers to the ability of humans to adapt to the time delay by modifying their tracking strategies. Subjects were assigned to either a perceptual adaptation or algorithmic prediction condition, and participated in four experimental sessions during which they attempted to center a reticle over a moving circular target using a HMD. Tracking performance was evaluated in terms of RMS error, and the adequacy of the adaptation and prediction solutions was evaluated by several comparisons of tracking efficiency within and between sessions. Results indicated that the algorithmic prediction solution was superior to the perceptual adaptation solution for compensating for the effects of time delay in a head-slaved tracking task.

Nelson, W. Todd; Hettinger, Lawrence J.; Haas, Michael W.; Russell, Christopher J.; Warm, Joel S.; Dember, William N.; Stoffregen, Thomas A.

1995-05-01

46

An Improved Method of Heterogeneity Compensation for the Convolution / Superposition Algorithm  

NASA Astrophysics Data System (ADS)

Purpose: To improve the accuracy of convolution/superposition (C/S) in heterogeneous material by developing a new algorithm: heterogeneity compensated superposition (HCS). Methods: C/S has proven to be a good estimator of the dose deposited in a homogeneous volume. However, near heterogeneities electron disequilibrium occurs, leading to the faster fall-off and re-buildup of dose. We propose to filter the actual patient density in a position and direction sensitive manner, allowing the dose deposited near interfaces to be increased or decreased relative to C/S. We implemented the effective density function as a multivariate first-order recursive filter and incorporated it into GPU-accelerated, multi-energetic C/S implementation. We compared HCS against C/S using the ICCR 2000 Monte-Carlo accuracy benchmark, 23 similar accuracy benchmarks and 5 patient cases. Results: Multi-energetic HCS increased the dosimetric accuracy for the vast majority of voxels; in many cases near Monte-Carlo results were achieved. We defined the per-voxel error, %|mm, as the minimum of the distance to agreement in mm and the dosimetric percentage error relative to the maximum MC dose. HCS improved the average mean error by 0.79 %|mm for the patient volumes; reducing the average mean error from 1.93 %|mm to 1.14 %|mm. Very low densities (i.e. < 0.1 g / cm3) remained problematic, but may be solvable with a better filter function. Conclusions: HCS improved upon C/S's density scaled heterogeneity correction with a position and direction sensitive density filter. This method significantly improved the accuracy of the GPU based algorithm reaching the accuracy levels of Monte Carlo based methods with performance in a few tenths of seconds per beam. Acknowledgement: Funding for this research was provided by the NSF Cooperative Agreement EEC9731748, Elekta / IMPAC Medical Systems, Inc. and the Johns Hopkins University. James Satterthwaite provided the Monte Carlo benchmark simulations.

Jacques, Robert; McNutt, Todd

2014-03-01

47

Advanced Transport Delay Compensation Algorithms: Results of Delay Measurement and Piloted Performance Tests  

NASA Technical Reports Server (NTRS)

This report summarizes the results of delay measurement and piloted performance tests that were conducted to assess the effectiveness of the adaptive compensator and the state space compensator for alleviating the phase distortion of transport delay in the visual system in the VMS at the NASA Langley Research Center. Piloted simulation tests were conducted to assess the effectiveness of two novel compensators in comparison to the McFarland predictor and the baseline system with no compensation. Thirteen pilots with heterogeneous flight experience executed straight-in and offset approaches, at various delay configurations, on a flight simulator where different predictors were applied to compensate for transport delay. The glideslope and touchdown errors, power spectral density of the pilot control inputs, NASA Task Load Index, and Cooper-Harper rating of the handling qualities were employed for the analyses. The overall analyses show that the adaptive predictor results in slightly poorer compensation for short added delay (up to 48 ms) and better compensation for long added delay (up to 192 ms) than the McFarland compensator. The analyses also show that the state space predictor is fairly superior for short delay and significantly superior for long delay than the McFarland compensator.

Guo, Liwen; Cardullo, Frank M.; Kelly, Lon C.

2007-01-01

48

A series-connected voltage source converter for voltage sag mitigation using vector control and a filter compensation algorithm  

Microsoft Academic Search

In this paper, a series-connected VSC for voltage sag mitigation is presented, which is characterized by a fast control logic, based on the decomposition of the unbalanced supply voltages into instantaneous positive and negative sequence components in two different rotating dq-coordinate systems. Furthermore, its performance is improved through the implementation of an algorithm to compensate for the steady-state voltage drop

Ambra Sannino; Jan Svensson

2000-01-01

49

Experiment Turbulence Compensation of 50-Gbaud/s Orbital-Angular-Momentum QPSK Signals using Intensity-only based SPGD Algorithm  

E-print Network

An intensity-only based algorithm is employed to compensate the turbulence effects on 50-Gbaud/s orbital angular momentum QPSK channels. By only measuring the intensity profile, the purity of the OAM beams is improved and ...

Xie, Guodong

50

The Atmospheric Compensation Component of a Landsat Land Surface Temperature (LST) Product: Assessment of Errors Expected for a North American Test Product  

NASA Astrophysics Data System (ADS)

The Landsat archive of thermal data (Landsats 4, 5 and 7) has gone through a rigorous calibration assessment and update. However, in order to be useful to most users the calibrated sensor reaching radiance must be corrected to surface temperatures by first compensating for atmospheric effects and then emissivity variations. The USGS is exploring the possibility of producing a LST product through a joint program with RIT (the atmospheric compensation component) and JPL (the emissivity compensation component). This paper addresses the atmospheric compensation component for an initial North American pilot study. In particular, the results of a comparison of retrieved water surface temperature (where emissivity is well known) and truth temperatures for over 800 sites are presented. The errors are broken down by cloud conditions with extremely good results for cloud-free conditions (errors less than 1 K). The results of the error assessment for North America by cloud class are presented along with a discussion of potential quality data for a LST product. An initial assessment of the LST errors observed for Landsat 8 bands 10 and 11 are also presented. The next steps on this effort include testing of a global atmospheric compensation approach and full integration of the atmospheric and emissivity compensation tools into an operational LST product.

Cook, M. J.; Schott, J. R.

2014-11-01

51

Atmospheric motion vector retrieval using improved tracer selection algorithm  

NASA Astrophysics Data System (ADS)

Tracer selection is the fundamental step in the retrieval of atmospheric motion vectors (AMVs). In this study, a new technique for tracer selection based on extracting the corner points in an infrared (IR) image of a geostationary satellite for the retrieval of AMVs is developed. Corner points are frequently used in computer vision to identify the important features of an image. These points are usually characterized by high gradient values of the image intensity in all directions and lie at the junctions of different brightness regions in the image. Corner points find application in computer vision for motion tracking, stereo vision, mosaics, etc., but this is the first time that the information from corners is used for tracer selection in AMV retrieval. In the present study, a commonly used Harris corner (HC) detection algorithm is followed to extract corners from the image intensity of an IR image. The tracers selected using the HC method are then passed on to the other steps of the retrieval algorithm, viz., tracking, height assignment, and quality control procedures for the retrieval of AMVs. For the initial development of the HC, Meteosat-7 IR images are used to derive AMVs for July and December 2010. The AMVs retrieved using HC are validated against collocated radiosonde observations, and the results are compared with the local anomaly (LA) method as reference. LA is used for tracer selection in operational AMV retrieval algorithm from the Indian geostationary satellite Kalpana-1. AMVs retrieved using HC have shown considerable improvement in the AMV accuracy over the AMVs derived using LA.

Kaur, Inderpreet; Deb, S. K.; Kishtawal, C. M.; Pal, P. K.; Kumar, Raj

2015-01-01

52

Precision laser surveying instrument using atmospheric turbulence compensation by determining the absolute displacement between two laser beam components  

DOEpatents

Atmospheric effects on sighting measurements are compensated for by adjusting any sighting measurements using a correction factor that does not depend on atmospheric state conditions such as temperature, pressure, density or turbulence. The correction factor is accurately determined using a precisely measured physical separation between two color components of a light beam (or beams) that has been generated using either a two-color laser or two lasers that project different colored beams. The physical separation is precisely measured by fixing the position of a short beam pulse and measuring the physical separation between the two fixed-in-position components of the beam. This precisely measured physical separation is then used in a relationship that includes the indexes of refraction for each of the two colors of the laser beam in the atmosphere through which the beam is projected, thereby to determine the absolute displacement of one wavelength component of the laser beam from a straight line of sight for that projected component of the beam. This absolute displacement is useful to correct optical measurements, such as those developed in surveying measurements that are made in a test area that includes the same dispersion effects of the atmosphere on the optical measurements. The means and method of the invention are suitable for use with either single-ended systems or a double-ended systems.

Veligdan, James T. (Manorville, NY)

1993-01-01

53

Coordinating the multivariable state-feedback controller on static synchronous compensator with Genetic Algorithm  

Microsoft Academic Search

In this paper, a linear quadratic regulator (LQR) and pole placement method for static synchronous compensator (STATCOM) control is introduced. STATCOM is a device capable of solving the power quality problems at the power system. These problems happen in milliseconds and because of the time limitation; it requires the STATCOM that has continuous reactive power control with fast response. The

S. Eshtehardiha; G. Shahgholian; H. Mahmoodian

2007-01-01

54

Algorithm for automatic atmospheric corrections to visible and near-IR satellite imagery  

Microsoft Academic Search

An algorithm is developed for automatic atmospheric correction of satellite imagery of the Earth's surface. The algorithm is based solely on the satellite image being corrected and on climatology of the area. It is applicable to low resolution (1 km field of view) and high resolution (10-80m field of view) imagery of land areas for the solar spectrum. The algorithm

Yoram J. Kaufman; Claudia Sendra

1988-01-01

55

Compensation for the effects of mutual coupling on direct data domain adaptive algorithms  

Microsoft Academic Search

This paper investigates the effects of mutual coupling between the elements of an array on direct data domain algorithms. Mutual coupling severely undermines the interference suppression capabilities of direct data domain algorithms. The method of moments (MoM) is used to evaluate the mutual coupling between the elements of a given array. The MoM admittance matrix is then used to eliminate

Raviraj S. Adve; Tapan Kumar Sarkar

2000-01-01

56

Efficient algorithm for locating and sizing series compensation devices in large power transmission grids: II. Solutions and applications  

NASA Astrophysics Data System (ADS)

In a companion manuscript (Frolov et al 2014 New J. Phys. 16 art. no.) , we developed a novel optimization method for the placement, sizing, and operation of flexible alternating current transmission system (FACTS) devices to relieve transmission network congestion. Specifically, we addressed FACTS that provide series compensation (SC) via modification of line inductance. In this sequel manuscript, this heuristic algorithm and its solutions are explored on a number of test cases: a 30-bus test network and a realistically-sized model of the Polish grid (2700 nodes and 3300 lines). The results from the 30-bus network are used to study the general properties of the solutions, including nonlocality and sparsity. The Polish grid is used to demonstrate the computational efficiency of the heuristics that leverage sequential linearization of power flow constraints, and cutting plane methods that take advantage of the sparse nature of the SC placement solutions. Using these approaches, we can use the algorithm to solve a Polish transmission grid in tens of seconds. We explore the utility of the algorithm by analyzing transmission networks congested by (i) uniform load growth, (ii) multiple overloaded configurations, and (iii) sequential generator retirements.

Frolov, Vladimir; Backhaus, Scott; Chertkov, Misha

2014-10-01

57

Design of static synchronous series compensator based damping controller employing invasive weed optimization algorithm.  

PubMed

This paper proposes designing of Static Synchronous Series Compensator (SSSC) based damping controller to enhance the stability of a Single Machine Infinite Bus (SMIB) system by means of Invasive Weed Optimization (IWO) technique. Conventional PI controller is used as the SSSC damping controller which takes rotor speed deviation as the input. The damping controller parameters are tuned based on time integral of absolute error based cost function using IWO. Performance of IWO based controller is compared to that of Particle Swarm Optimization (PSO) based controller. Time domain based simulation results are presented and performance of the controllers under different loading conditions and fault scenarios is studied in order to illustrate the effectiveness of the IWO based design approach. PMID:25140288

Ahmed, Ashik; Al-Amin, Rasheduzzaman; Amin, Ruhul

2014-01-01

58

Analysis and compensation of the effects of analog VLSI arithmetic on the LMS algorithm.  

PubMed

Analog very large scale integration implementations of neural networks can compute using a fraction of the size and power required by their digital counterparts. However, intrinsic limitations of analog hardware, such as device mismatch, charge leakage, and noise, reduce the accuracy of analog arithmetic circuits, degrading the performance of large-scale adaptive systems. In this paper, we present a detailed mathematical analysis that relates different parameters of the hardware limitations to specific effects on the convergence properties of linear perceptrons trained with the least-mean-square (LMS) algorithm. Using this analysis, we derive design guidelines and introduce simple on-chip calibration techniques to improve the accuracy of analog neural networks with a small cost in die area and power dissipation. We validate our analysis by evaluating the performance of a mixed-signal complementary metal-oxide-semiconductor implementation of a 32-input perceptron trained with LMS. PMID:21622073

Carvajal, Gonzalo; Figueroa, Miguel; Sbarbaro, Daniel; Valenzuela, Waldo

2011-07-01

59

Brightness-compensated 3-D optical flow algorithm for monitoring cochlear motion patterns  

NASA Astrophysics Data System (ADS)

A method for three-dimensional motion analysis designed for live cell imaging by fluorescence confocal microscopy is described. The approach is based on optical flow computation and takes into account brightness variations in the image scene that are not due to motion, such as photobleaching or fluorescence variations that may reflect changes in cellular physiology. The 3-D optical flow algorithm allowed almost perfect motion estimation on noise-free artificial sequences, and performed with a relative error of <10% on noisy images typical of real experiments. The method was applied to a series of 3-D confocal image stacks from an in vitro preparation of the guinea pig cochlea. The complex motions caused by slow pressure changes in the cochlear compartments were quantified. At the surface of the hearing organ, the largest motion component was the transverse one (normal to the surface), but significant radial and longitudinal displacements were also present. The outer hair cell displayed larger radial motion at their basolateral membrane than at their apical surface. These movements reflect mechanical interactions between different cellular structures, which may be important for communicating sound-evoked vibrations to the sensory cells. A better understanding of these interactions is important for testing realistic models of cochlear mechanics.

von Tiedemann, Miriam; Fridberger, Anders; Ulfendahl, Mats; de Monvel, Jacques Boutet

2010-09-01

60

S. 2466: This Act may be cited as the National Atmospheric Nuclear Testing Compensation Act of 1990. Introduced in the Senate of the United States, One Hundredth First Congress, Second Session, April 19, 1990  

SciTech Connect

This bill would amend Title XXI of the Public Health Service Act to provide for the establishment of an atmospheric nuclear testing compensation program to compensate civilians living down wind of the Nevada Test Site during above-ground testing of nuclear weapons and miners exposed in underground uranium mines supplying uranium for the primary use and benefit of the nuclear weapons program. The bill describes technical assistance and information, administrative procedures for filing a petition, determination of eligibility, and amount of compensation.

Not Available

1990-01-01

61

Assessment, Validation, and Refinement of the Atmospheric Correction Algorithm for the Ocean Color Sensors. Chapter 19  

NASA Technical Reports Server (NTRS)

The primary focus of this proposed research is for the atmospheric correction algorithm evaluation and development and satellite sensor calibration and characterization. It is well known that the atmospheric correction, which removes more than 90% of sensor-measured signals contributed from atmosphere in the visible, is the key procedure in the ocean color remote sensing (Gordon and Wang, 1994). The accuracy and effectiveness of the atmospheric correction directly affect the remotely retrieved ocean bio-optical products. On the other hand, for ocean color remote sensing, in order to obtain the required accuracy in the derived water-leaving signals from satellite measurements, an on-orbit vicarious calibration of the whole system, i.e., sensor and algorithms, is necessary. In addition, it is important to address issues of (i) cross-calibration of two or more sensors and (ii) in-orbit vicarious calibration of the sensor-atmosphere system. The goal of these researches is to develop methods for meaningful comparison and possible merging of data products from multiple ocean color missions. In the past year, much efforts have been on (a) understanding and correcting the artifacts appeared in the SeaWiFS-derived ocean and atmospheric produces; (b) developing an efficient method in generating the SeaWiFS aerosol lookup tables, (c) evaluating the effects of calibration error in the near-infrared (NIR) band to the atmospheric correction of the ocean color remote sensors, (d) comparing the aerosol correction algorithm using the singlescattering epsilon (the current SeaWiFS algorithm) vs. the multiple-scattering epsilon method, and (e) continuing on activities for the International Ocean-Color Coordinating Group (IOCCG) atmospheric correction working group. In this report, I will briefly present and discuss these and some other research activities.

Wang, Menghua

2003-01-01

62

Mars Entry Atmospheric Data System Trajectory Reconstruction Algorithms and Flight Results  

NASA Technical Reports Server (NTRS)

The Mars Entry Atmospheric Data System is a part of the Mars Science Laboratory, Entry, Descent, and Landing Instrumentation project. These sensors are a system of seven pressure transducers linked to ports on the entry vehicle forebody to record the pressure distribution during atmospheric entry. These measured surface pressures are used to generate estimates of atmospheric quantities based on modeled surface pressure distributions. Specifically, angle of attack, angle of sideslip, dynamic pressure, Mach number, and freestream atmospheric properties are reconstructed from the measured pressures. Such data allows for the aerodynamics to become decoupled from the assumed atmospheric properties, allowing for enhanced trajectory reconstruction and performance analysis as well as an aerodynamic reconstruction, which has not been possible in past Mars entry reconstructions. This paper provides details of the data processing algorithms that are utilized for this purpose. The data processing algorithms include two approaches that have commonly been utilized in past planetary entry trajectory reconstruction, and a new approach for this application that makes use of the pressure measurements. The paper describes assessments of data quality and preprocessing, and results of the flight data reduction from atmospheric entry, which occurred on August 5th, 2012.

Karlgaard, Christopher D.; Kutty, Prasad; Schoenenberger, Mark; Shidner, Jeremy; Munk, Michelle

2013-01-01

63

An Atmospheric Correction Algorithm for FY-3/ MERSI Data over the Land: First Results  

NASA Astrophysics Data System (ADS)

Feng-Yun (FY-3) is the second Chinese Polar Orbiting Meteorological Satellite with global, three-dimensional, quantitative, and multispectral capabilities. Medium Resolution Spectral Imager (MERSI) has 20 channels onboard the FY-3A and FY-3B satellite. MERSI has five channels (four VIS and one thermal IR), with a spatial resolution of 250 m. Prior to the derivation of various biophysical parameters based on surface reflectance, the top of the atmosphere signal need to be radiometrically calibrated and corrected for atmospheric effects. This paper presents an atmospheric correction algorithm for FY3/MERSI in the visible to near-infrared band over the land. Previous operational correction schemes have assumed a Lambertian surface. A new atmospheric correction algorithm is developed to take into account the directional properties of the observed surface by a kernel-based Bi-directional Reflectance Distribution Function (BRDF) model. This algorithm is applied to remote sensing data from FY3/MERSI and compared with Moderate Resolution Imaging Spectro radiometer (MODIS) surface reflectance products (MOD09GA). It is found in the study that the relative accuracy of data, obtained with these two devices, was consistent with the acceptable overall accuracy of 73%. Furthermore, spatial resolution of MERSI is superior as compared to that of MODIS. Therefore, FY-3/MERSI can serve a reliable and new data source for quantifying global environmental change.

Guang, Jie; Xue, Yong; Liang, Shunlin; Liu, Qiang; Mei, LinLu; Shi, Yuanli

2014-05-01

64

Development of an Aircraft Approach and Departure Atmospheric Profile Generation Algorithm  

NASA Technical Reports Server (NTRS)

In support of NASA Virtual Airspace Modeling and Simulation (VAMS) project, an effort was initiated to develop and test techniques for extracting meteorological data from landing and departing aircraft, and for building altitude based profiles for key meteorological parameters from these data. The generated atmospheric profiles will be used as inputs to NASA s Aircraft Vortex Spacing System (AVOLSS) Prediction Algorithm (APA) for benefits and trade analysis. A Wake Vortex Advisory System (WakeVAS) is being developed to apply weather and wake prediction and sensing technologies with procedures to reduce current wake separation criteria when safe and appropriate to increase airport operational efficiency. The purpose of this report is to document the initial theory and design of the Aircraft Approach Departure Atmospheric Profile Generation Algorithm.

Buck, Bill K.; Velotas, Steven G.; Rutishauser, David K. (Technical Monitor)

2004-01-01

65

Preliminary investigation of the retrieval algorithm of atmospheric aerosol distribution with a space-borne lidar  

Microsoft Academic Search

Problems arising in the space-borne lidar remote sensing of the atmospheric aerosol distribution are discussed. The basic uncertainty in the retrieval algorithm results from the presence of two unknowns (the extinction coefficient and the backscattering coefficient) which can be determined with only one measurement (i.e., echo power). This uncertainty exists in both ground-based and space-borne lidar remote sensing. The formulized

Jinhuan Qiu; Daren Lu

1988-01-01

66

Adaptation of a Hyperspectral Atmospheric Correction Algorithm for Multi-spectral Ocean Color Data in Coastal Waters. Chapter 3  

NASA Technical Reports Server (NTRS)

This SIMBIOS contract supports several activities over its three-year time-span. These include certain computational aspects of atmospheric correction, including the modification of our hyperspectral atmospheric correction algorithm Tafkaa for various multi-spectral instruments, such as SeaWiFS, MODIS, and GLI. Additionally, since absorbing aerosols are becoming common in many coastal areas, we are making the model calculations to incorporate various absorbing aerosol models into tables used by our Tafkaa atmospheric correction algorithm. Finally, we have developed the algorithms to use MODIS data to characterize thin cirrus effects on aerosol retrieval.

Gao, Bo-Cai; Montes, Marcos J.; Davis, Curtiss O.

2003-01-01

67

Algorithm for Simulating Atmospheric Turbulence and Aeroelastic Effects on Simulator Motion Systems  

NASA Technical Reports Server (NTRS)

Atmospheric turbulence produces high frequency accelerations in aircraft, typically greater than the response to pilot input. Motion system equipped flight simulators must present cues representative of the aircraft response to turbulence in order to maintain the integrity of the simulation. Currently, turbulence motion cueing produced by flight simulator motion systems has been less than satisfactory because the turbulence profiles have been attenuated by the motion cueing algorithms. This report presents a new turbulence motion cueing algorithm, referred to as the augmented turbulence channel. Like the previous turbulence algorithms, the output of the channel only augments the vertical degree of freedom of motion. This algorithm employs a parallel aircraft model and an optional high bandwidth cueing filter. Simulation of aeroelastic effects is also an area where frequency content must be preserved by the cueing algorithm. The current aeroelastic implementation uses a similar secondary channel that supplements the primary motion cue. Two studies were conducted using the NASA Langley Visual Motion Simulator and Cockpit Motion Facility to evaluate the effect of the turbulence channel and aeroelastic model on pilot control input. Results indicate that the pilot is better correlated with the aircraft response, when the augmented channel is in place.

Ercole, Anthony V.; Cardullo, Frank M.; Kelly, Lon C.; Houck, Jacob A.

2012-01-01

68

The Computational Complexity, Parallel Scalability, and Performance of Atmospheric Data Assimilation Algorithms  

NASA Technical Reports Server (NTRS)

The computational complexity of algorithms for Four Dimensional Data Assimilation (4DDA) at NASA's Data Assimilation Office (DAO) is discussed. In 4DDA, observations are assimilated with the output of a dynamical model to generate best-estimates of the states of the system. It is thus a mapping problem, whereby scattered observations are converted into regular accurate maps of wind, temperature, moisture and other variables. The DAO is developing and using 4DDA algorithms that provide these datasets, or analyses, in support of Earth System Science research. Two large-scale algorithms are discussed. The first approach, the Goddard Earth Observing System Data Assimilation System (GEOS DAS), uses an atmospheric general circulation model (GCM) and an observation-space based analysis system, the Physical-space Statistical Analysis System (PSAS). GEOS DAS is very similar to global meteorological weather forecasting data assimilation systems, but is used at NASA for climate research. Systems of this size typically run at between 1 and 20 gigaflop/s. The second approach, the Kalman filter, uses a more consistent algorithm to determine the forecast error covariance matrix than does GEOS DAS. For atmospheric assimilation, the gridded dynamical fields typically have More than 10(exp 6) variables, therefore the full error covariance matrix may be in excess of a teraword. For the Kalman filter this problem can easily scale to petaflop/s proportions. We discuss the computational complexity of GEOS DAS and our implementation of the Kalman filter. We also discuss and quantify some of the technical issues and limitations in developing efficient, in terms of wall clock time, and scalable parallel implementations of the algorithms.

Lyster, Peter M.; Guo, J.; Clune, T.; Larson, J. W.; Atlas, Robert (Technical Monitor)

2001-01-01

69

A new raytracing algorithm to compute slant total delays in a mesoscale atmospheric model  

NASA Astrophysics Data System (ADS)

Ray-tracing is essential to accurately simulate Global Positioning System (GPS) Slant Total Delays (STD) in a mesoscale atmospheric model. A rigorous ray-tracing algorithm based on Fermat's principle was developed to simulate the propagation of radio signals in a gridded 3D refractivity field. The unique in the proposed algorithm is that the solution automatically involves the exact location of the receiver and the satellite, i.e. 'shooting' is not required. The structured non-linear system of equations, arising due to the applied finite difference scheme, is solved by Newton's iteration. For elevation angles as low as 5 degree at a ground-based receiver a single Newton iteration turns out to be sufficient. Subsequently the algorithm allows us to simulate about 1500 STDs per second on a single CPU. Having developed the forward operator for STDs, we constructed the tangent linear and adjoint code for sensitivity and variational data analysis. First results from three potential applications of the proposed ray-tracing algorithm are presented: (1) monitoring STD data processed at the GFZ Potsdam against European Centre for Medium-Range Weather Forecasts (ECMWF) analysis, (2) vertical profiling, i.e. the retrieval of the refractivity profile above a ground based receiver from the STD data by using a least square adjustment, and (3) direct mapping.

Zus, Florian; Bender, Michael; Dick, Galina; Deng, Zhiguo; Heise, Stefan; Wickert, Jens

2010-05-01

70

The Algorithm Theoretical Basis Document for the GLAS Atmospheric Data Products  

NASA Technical Reports Server (NTRS)

The purpose of this document is to present a detailed description of the algorithm theoretical basis for each of the GLAS data products. This will be the final version of this document. The algorithms were initially designed and written based on the authors prior experience with high altitude lidar data on systems such as the Cloud and Aerosol Lidar System (CALS) and the Cloud Physics Lidar (CPL), both of which fly on the NASA ER-2 high altitude aircraft. These lidar systems have been employed in many field experiments around the world and algorithms have been developed to analyze these data for a number of atmospheric parameters. CALS data have been analyzed for cloud top height, thin cloud optical depth, cirrus cloud emittance (Spinhirne and Hart, 1990) and boundary layer depth (Palm and Spinhirne, 1987, 1998). The successor to CALS, the CPL, has also been extensively deployed in field missions since 2000 including the validation of GLAS and CALIPSO. The CALS and early CPL data sets also served as the basis for the construction of simulated GLAS data sets which were then used to develop and test the GLAS analysis algorithms.

Palm, Stephen P.; Hart, William D.; Hlavka, Dennis L.; Welton, Ellsworth J.; Spinhirne, James D.

2012-01-01

71

ACTS Rain Fade Compensation  

NASA Technical Reports Server (NTRS)

Performance status of the Adaptive Rain Fade Compensation includes: (1) The rain fade protocol is functional detecting fades, providing an additional 10 dB of margin and seamless transitions to and from coded operation; (2) The stabilization of the link margins and the optimization of rain fade decision thresholds has resulted in improved BER performance; (3) Characterization of the fade compensation algorithm is ongoing.

Coney, Thom A.

1996-01-01

72

Motion compensation for ultra wide band SAR  

NASA Technical Reports Server (NTRS)

This paper describes an algorithm that combines wavenumber domain processing with a procedure that enables motion compensation to be applied as a function of target range and azimuth angle. First, data are processed with nominal motion compensation applied, partially focusing the image, then the motion compensation of individual subpatches is refined. The results show that the proposed algorithm is effective in compensating for deviations from a straight flight path, from both a performance and a computational efficiency point of view.

Madsen, S.

2001-01-01

73

Algorithm development for intensity modulated continuous wave laser absorption spectrometry in atmospheric CO2 measurements  

NASA Astrophysics Data System (ADS)

Currently, NASA Langley Research Center (LaRC) and ITT are jointly developing algorithms for demonstration of range discrimination using ITT's laser absorption spectrometer (LAS), which is being evaluated for the future NASA Active Sensing of CO2 Emissions during Nights, Days, and Seasons (ASCENDS) mission. The objective of this Decadal Survey mission is to measure atmospheric column CO2 mixing ratios (XCO2) for improved determination of atmospheric carbon sources and sinks. Intensity Modulated Continuous Wave (IM-CW) techniques are used in this LAS approach. The LAS is designed to simultaneously measure CO2 and O2 columns, and these measurements are used to determine the required XCO2 column. The LAS measurements are enabled by the multi-channel operation of the instrument at 1.57 and 1.26-um for CO2 and O2, respectively. The algorithm development for the IM-CW techniques of the multi-channel LAS is focused on addressing key retrieval issues such as surface signal detection, thin cloud and/or aerosol layer rejection, vertical atmospheric range resolution, and optimizing the size of the measurement footprint. With these considerations, the modulation algorithm needs to maintain high enough signal-to-noise ratio (SNR) so that the mission scientific goals can be reached. A basic selection of the modulation algorithms that make XCO2 measurement and thin cloud rejection possible is the stepped frequency modulation scheme and a similar scheme of swept sine modulation. The differences between these two schemes for thin cloud rejection are small, assuming the proper selection of parameters is made. The stepped frequency approach is only a quantified version of swept sine method for the frequencies used. Swept sine scheme is a very common modulation technique for range discrimination, while the consideration of the stepped frequency scheme is based on the history of the rolling-tone modulation used in the instrument in previous successful column CO2 measurements. The stepped frequency approach provides minimal risk in the technology development for thin cloud rejection. To obtain a specified vertical resolution, a requisite bandwidth is needed for the stepped frequency/swept sine schemes. The requirements of horizontal resolution and SNR are obtained through the integration time of either stepped frequency or swept sine approaches. Based on these considerations and instrument hardware limitations, the frequencies for the intensity modulation approaches were selected and implemented in the current LAS. The LAS has six wavelength channels: 3 for CO2, 2 for O2 and 1 for background measurements. The frequencies of the stepped frequency algorithm vary from 200 to about 500 KHz with 100-KHz bandwidth in each individual channel. Reduction of potential spectral interference is also considered in the selection of the frequencies. Details of the development of the IM-CW algorithms and results from flight testing of these techniques during the spring and summer of 2011 are discussed in this paper.

Lin, B.; Harrison, F. W.; Browell, E. V.; Dobler, J. T.; Bryant, R. B.

2011-12-01

74

Atmospheric correction for ocean colour images using a classification and a neuro-variational algorithm  

NASA Astrophysics Data System (ADS)

Radiometers on board satellite measure the solar radiation reflected by both ocean and atmosphere at several wavelengths. One difficulty is that the signal is strongly polluted by the contribution of the atmosphere. An important step in the processing of ocean colour images is the so-called "atmospheric correction" that consists in removing the contribution of the atmospheric signal to solely retrieve the ocean contribution. Due to the presence of aerosols in the atmosphere, this contribution cannot be predicted a priori. Thus, standard algorithms use a part of the signal, generally the near-infrared bands, to deduce the contribution of aerosols to the signal. It is necessary to make some assumptions on the contribution of the ocean for these bands. Most of the time this contribution is determined a priori. In some situations, this approach is not relevant. Two main problems can occur: (1) The ocean contribution can not be determined a priori in the near-infrared bands; it is the case of most of the coastal waters where the content of the water is complex and not be predicted. (2) The near-infrared part of the signal is not enough to entirely deduce the aerosol contribution; it is the case of absorbing aerosol. To solve this problem, a methodology was proposed: NeuroVaria. It was based on the spectral matching principle: instead of making strong hypothesis on the oceanic contribution, a multispectral optimization is made on both oceanic and atmospheric signal. NeuroVaria alone was already validated in several cases. To improve the accuracy of the results and to process more situations, NeuroVaria was combined with a classification procedure in order to constrain the inversion. The classification was done with neuronal classifier (SOM map). The method was applied to the daily MODIS images off the Senegal coast. The resulting oceanic products were validated and a data archive of the daily MODIS data of the region is under construction. This database comprises the Chla-a concentration, the water leaving reflectance spectrum, the aerosol parameters.

Brajard, Julien; Diouf, Daouda; Crpon, Michel; Thiria, Sylvie

2013-04-01

75

Photonic-crystal fibers for dispersion compensation in short-pulse fiber laser sources: design algorithms and dispersion characterization  

Microsoft Academic Search

This work aims at developing a PCF-based stretcher for a sub-mJ fiber chirped pulse amplifier (FCPA) capable of correcting the higher-order dispersion of the amplifier chain and the pulse compressor. We develop a conveniently formalized algorithm for the design of PCFs and prove theoretically the possibility to engineer negative dispersion PCFs of a chosen sign of cubic and quartic phase.

A. Fernandez; Lingxiao Zhu; A.-J. Verhoef; A. Baltuska; E. E. Serebryannikov; A. M. Zheltikov; D. A. Sidorov-Biryukov; J. C. Knight

2007-01-01

76

A SAR image-formation algorithm that compensates for the spatially-variant effects of antenna motion  

SciTech Connect

A synthetic aperture radar (SAR) obtains azimuth resolution by combining data from a number of points along a specified path. Uncompensated antenna motion that deviates significantly from the desired path produces spatially-variant errors in the output image. The algorithm presented in this paper corrects many of these motion-related errors. In this respect, it is similar to time-domain convolution, but it is more computationally efficient. The algorithm uses overlapped subapertures in a three-step image-formation process: coarse-resolution azimuth processing, fine-resolution range processing, and fine-resolution azimuth processing. Range migration is corrected after the first stage, based on coarse azimuth position. Prior to the final azimuth-compression step, data coordinates, are determined to fine resolution in range and coarse resolution in azimuth. This coordinate information is combined with measured motion data to generate a phase correction that removes spatially-variant errors. The algorithm is well-suited for real-time applications, particularly where large flight-path deviations must be tolerated.

Burns, B.L.; Cordaro, J.T.

1994-03-01

77

Ground based measurements on reflectance towards validating atmospheric correction algorithms on IRS-P6 AWiFS data  

NASA Astrophysics Data System (ADS)

In Earth observation, the atmosphere has a non-negligible influence on the visible and infrared radiation which is strong enough to modify the reflected electromagnetic signal and at-target reflectance. Scattering of solar irradiance by atmospheric molecules and aerosol generates path radiance, which increases the apparent surface reflectance over dark surfaces while absorption by aerosols and other molecules in the atmosphere causes loss of brightness to the scene, as recorded by the satellite sensor. In order to derive precise surface reflectance from satellite image data, it is indispensable to apply the atmospheric correction which serves to remove the effects of molecular and aerosol scattering. In the present study, we have implemented a fast atmospheric correction algorithm to IRS-P6 AWiFS satellite data which can effectively retrieve surface reflectance under different atmospheric and surface conditions. The algorithm is based on MODIS climatology products and simplified use of Second Simulation of Satellite Signal in Solar Spectrum (6S) radiative transfer code, which is used to generate look-up-tables (LUTs). The algorithm requires information on aerosol optical depth for correcting the satellite dataset. The proposed method is simple and easy to implement for estimating surface reflectance from the at sensor recorded signal, on a per pixel basis. The atmospheric correction algorithm has been tested for different IRS-P6 AWiFS False color composites (FCC) covering the ICRISAT Farm, Patancheru, Hyderabad, India under varying atmospheric conditions. Ground measurements of surface reflectance representing different land use/land cover, i.e., Red soil, Chick Pea crop, Groundnut crop and Pigeon Pea crop were conducted to validate the algorithm and found a very good match between surface reflectance and atmospherically corrected reflectance for all spectral bands. Further, we aggregated all datasets together and compared the retrieved AWiFS reflectance with aggregated ground measurements which showed a very good correlation of 0.96 in all four spectral bands (i.e. green, red, NIR and SWIR). In order to quantify the accuracy of the proposed method in the estimation of the surface reflectance, the root mean square error (RMSE) associated to the proposed method was evaluated. The analysis of the ground measured versus retrieved AWiFS reflectance yielded smaller RMSE values in case of all four spectral bands. EOS TERRA/AQUA MODIS derived AOD exhibited very good correlation of 0.92 and the data sets provides an effective means for carrying out atmospheric corrections in an operational way. Keywords: Atmospheric correction, 6S code, MODIS, Spectroradiometer, Sun-Photometer

Rani Sharma, Anu; Kharol, Shailesh Kumar; Kvs, Badarinath; Roy, P. S.

78

An algorithm for variational data assimilation of contact concentration measurements for atmospheric chemistry models  

NASA Astrophysics Data System (ADS)

Contact concentration measurement data assimilation problem is considered for convection-diffusion-reaction models originating from the atmospheric chemistry study. High dimensionality of models imposes strict requirements on the computational efficiency of the algorithms. Data assimilation is carried out within the variation approach on a single time step of the approximated model. A control function is introduced into the source term of the model to provide flexibility for data assimilation. This function is evaluated as the minimum of the target functional that connects its norm to a misfit between measured and model-simulated data. In the case mathematical model acts as a natural Tikhonov regularizer for the ill-posed measurement data inversion problem. This provides flow-dependent and physically-plausible structure of the resulting analysis and reduces a need to calculate model error covariance matrices that are sought within conventional approach to data assimilation. The advantage comes at the cost of the adjoint problem solution. This issue is solved within the frameworks of splitting-based realization of the basic convection-diffusion-reaction model. The model is split with respect to physical processes and spatial variables. A contact measurement data is assimilated on each one-dimensional convection-diffusion splitting stage. In this case a computationally-efficient direct scheme for both direct and adjoint problem solution can be constructed based on the matrix sweep method. Data assimilation (or regularization) parameter that regulates ratio between model and data in the resulting analysis is obtained with Morozov discrepancy principle. For the proper performance the algorithm takes measurement noise estimation. In the case of Gaussian errors the probability that the used Chi-squared-based estimate is the upper one acts as the assimilation parameter. A solution obtained can be used as the initial guess for data assimilation algorithms that assimilate outside the splitting stages and involve iterations. Splitting method stage that is responsible for chemical transformation processes is realized with the explicit discrete-analytical scheme with respect to time. The scheme is based on analytical extraction of the exponential terms from the solution. This provides unconditional positive sign for the evaluated concentrations. Splitting-based structure of the algorithm provides means for efficient parallel realization. The work is partially supported by the Programs No 4 of Presidium RAS and No 3 of Mathematical Department of RAS, by RFBR project 11-01-00187 and Integrating projects of SD RAS No 8 and 35. Our studies are in the line with the goals of COST Action ES1004.

Penenko, Alexey; Penenko, Vladimir

2014-05-01

79

Analytical algorithm for modeling polarized solar radiation transfer through the atmosphere for application in processing complex lidar and radiometer measurements  

NASA Astrophysics Data System (ADS)

Inversion algorithms and program packages recently created for processing data of the ground-based radiometer spectral measurements along with lidar multi-wavelength measurements are extremely multiparametric. Therefore, it is very important to develop an efficient program module for computations of functions modeling measurements by a sun-radiometer in the inversion procedure. In this paper, we present the analytical version of such efficient algorithm and analytical code on C++ designed for performance of algorithm testing. The code computes multiple scattering of the Sun light in the atmosphere. Data output are the radiance and linear polarization parameters angular patterns at a preselected altitude. The atmosphere model with mixed aerosol and molecular scattering is given approximately as the homogeneous atmosphere model. The algorithm testing has been carried out by comparison of computed data with accurate data obtained on the base of the discrete-ordinate code. Errors of estimates of downward radiance above the Earth surface turned out to be within 10%-15%.. The analytical solution construction concept has taken from the scalar task of solar radiation transfer in the atmosphere where an approximate analytical solution was developed. Taking into account the fact that aerosol phase functions are highly forward elongated, the multi-component method of solving vector transfer equations and small-angle approximation have been used. Generalization of the scalar approach to the polarization parameters is described.

Chaikovskaya, L.; Dubovik, O.; Litvinov, P.; Grudo, J.; Lopatsin, A.; Chaikovsky, A.; Denisov, S.

2015-01-01

80

Assessment of Polarization Effect on Efficiency of Levenberg-Marquardt Algorithm in Case of Thin Atmosphere Over Black Surface  

NASA Technical Reports Server (NTRS)

The Levenberg-Marquardt algorithm [1, 2] provides a numerical iterative solution to the problem of minimization of a function over a space of its parameters. In our work, the Levenberg-Marquardt algorithm retrieves optical parameters of a thin (single scattering) plane parallel atmosphere irradiated by collimated infinitely wide monochromatic beam of light. Black ground surface is assumed. Computational accuracy, sensitivity to the initial guess and the presence of noise in the signal, and other properties of the algorithm are investigated in scalar (using intensity only) and vector (including polarization) modes. We consider an atmosphere that contains a mixture of coarse and fine fractions. Following [3], the fractions are simulated using Henyey-Greenstein model. Though not realistic, this assumption is very convenient for tests [4, p.354]. In our case it yields analytical evaluation of Jacobian matrix. Assuming the MISR geometry of observation [5] as an example, the average scattering cosines and the ratio of coarse and fine fractions, the atmosphere optical depth, and the single scattering albedo, are the five parameters to be determined numerically. In our implementation of the algorithm, the system of five linear equations is solved using the fast Cramer s rule [6]. A simple subroutine developed by the authors, makes the algorithm independent from external libraries. All Fortran 90/95 codes discussed in the presentation will be available immediately after the meeting from sergey.v.korkin@nasa.gov by request.

Korkin, S.; Lyapustin, A.

2012-01-01

81

Compensation Chemistry  

ERIC Educational Resources Information Center

Congress, the news media, and the Internal Revenue Service (IRS) continue to cast a wary eye on the compensation of nonprofit leaders. Hence, any college or university board that falls short of IRS expectations in its procedures for setting the president's compensation is putting the president, other senior officials, and board members at

Roady, Celia

2008-01-01

82

Atmosphere  

NSDL National Science Digital Library

What is this atmosphere that surrounds the Earth? This instructional tutorial, part of an interactive laboratory series for grades 8-12, introduces students to the structure, effects, and components of the atmosphere. Here students investigate the composition of the atmosphere; effects of temperature, pressure, and ozone; the greenhouse effect; and how Earth compares with other planets. Interactive activities present students with opportunities to explore ideas and answer questions about the atmosphere, including its structure, the making of ozone, rocket launching, and measuring the atmosphere. Pop-up boxes provide additional information on topics such as dust, rain, and atmospheric composition. Students complete a final written review of six questions about the atmosphere. Copyright 2005 Eisenhower National Clearinghouse

University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

2003-01-01

83

An Adaptive Numeric Predictor-corrector Guidance Algorithm for Atmospheric Entry Vehicles. M.S. Thesis - MIT, Cambridge  

NASA Technical Reports Server (NTRS)

An adaptive numeric predictor-corrector guidance is developed for atmospheric entry vehicles which utilize lift to achieve maximum footprint capability. Applicability of the guidance design to vehicles with a wide range of performance capabilities is desired so as to reduce the need for algorithm redesign with each new vehicle. Adaptability is desired to minimize mission-specific analysis and planning. The guidance algorithm motivation and design are presented. Performance is assessed for application of the algorithm to the NASA Entry Research Vehicle (ERV). The dispersions the guidance must be designed to handle are presented. The achievable operational footprint for expected worst-case dispersions is presented. The algorithm performs excellently for the expected dispersions and captures most of the achievable footprint.

Spratlin, Kenneth Milton

1987-01-01

84

Employee compensation.  

PubMed

All practice owners and managers struggle with the concept of "fair compensation." Many factors enter into determining fair compensation. More managers are placing emphasis on production or contributions to the practice in making compensation decisions. Several incentive or bonus programs are discussed. If the contributions to the business can be measured, these areas may possibly be used for incentive programs. As owners and managers we need to do a better job of explaining and showing to our employees the total cost for staffing the practice. PMID:8778945

Garcia, E

1996-02-01

85

Atmospheric Motion Vectors Derived via a New Nested Tracking Algorithm Developed for the GOES-R Advanced Baseline Imager (ABI)  

NASA Astrophysics Data System (ADS)

A new Atmospheric Motion Vector (AMV) nested tracking algorithm has been developed for the Advanced Baseline Imager (ABI) to be flown on NOAA's future GOES-R satellite. The algorithm has been designed to capture the dominant motion in each target scene from a family of local motion vectors derived for each target scene. Capturing this dominant motion is achieved through use of a two-dimensional clustering algorithm that segregates local displacements into clusters. The dominant motion is taken to be the average of the local displacements of points belonging to the largest cluster. This approach prevents excessive averaging of motion that may be occurring at multiple levels or at different scales that can lead to a slow speed bias and a poor quality AMV. A representative height is assigned to the dominant motion vector through exclusive use of cloud heights from pixels belonging to the largest cluster. This algorithm has been demonstrated to significantly improve the slow speed bias typically observed in AMVs derived from satellite imagery. Meteosat SEVERI imagery is serving as an important GOES-R ABI proxy data source for the development, testing, and validation of the GOES-R AMV algorithms given its similarities (spectral coverage, pixel resolution, and scanning rate) and performance (spectral noise, navigation/registration) to the future GOES-R ABI. The new GOES-R AMV algorithm is also being applied to the instrumentation on the current operational GOES series of satellites and is expected to replace the heritage AMV algorithm being used in NESDIS operations today. Plans at NOAA/NESDIS also include using the new GOES-R AMV algorithm to generate AMVs from the future VIIRS instrument on the NPP satellite. Details of the GOES-R ABI AMV algorithm and the validation results will be presented and discussed.

Daniels, J.; Bresky, W.; Wanzong, S.; Velden, C.

2012-12-01

86

An algorithm for retrieval of ocean surface and atmospheric parameters from the observations of the scanning multichannel microwave radiometer (SMMR)  

NASA Technical Reports Server (NTRS)

A formalism was developed which can be used to interpret the data in terms of sea surface temperature, sea surface wind speed, and the atmospheric overburden of water vapor and liquid water. It was shown with reasonable instrumental performance assumptions, these parameters could be derived to useful accuracies. Although the algorithms were not derived for use in rain, it is shown that, at least, token rain rates can be tolerated without invalidating the retrieved geophysical parameters.

Wilheit, T. T.; Chang, A. T. C.

1979-01-01

87

Genetic algorithm applied to a Soil-Vegetation-Atmosphere system: Sensitivity and uncertainty analysis  

NASA Astrophysics Data System (ADS)

Numerical models are of precious help for predicting water fluxes in the vadose zone and more specifically in Soil-Vegetation-Atmosphere (SVA) systems. For such simulations, robust models and representative soil hydraulic parameters are required. Calibration of unsaturated hydraulic properties is known to be a difficult optimization problem due to the high non-linearity of the water flow equations. Therefore, robust methods are needed to avoid the optimization process to lead to non-optimal parameters. Evolutionary algorithms and specifically genetic algorithms (GAs) are very well suited for those complex parameter optimization problems. Additionally, GAs offer the opportunity to assess the confidence in the hydraulic parameter estimations, because of the large number of model realizations. The SVA system in this study concerns a pine stand on a heterogeneous sandy soil (podzol) in the Campine region in the north of Belgium. Throughfall and other meteorological data and water contents at different soil depths have been recorded during one year at a daily time step in two lysimeters. The water table level, which is varying between 95 and 170 cm, has been recorded with intervals of 0.5 hour. The leaf area index was measured as well at some selected time moments during the year in order to evaluate the energy which reaches the soil and to deduce the potential evaporation. Water contents at several depths have been recorded. Based on the profile description, five soil layers have been distinguished in the podzol. Two models have been used for simulating water fluxes: (i) a mechanistic model, the HYDRUS-1D model, which solves the Richards' equation, and (ii) a compartmental model, which treats the soil profile as a bucket into which water flows until its maximum capacity is reached. A global sensitivity analysis (Morris' one-at-a-time sensitivity analysis) was run previously to the calibration, in order to check the sensitivity in the chosen parameter search space. For the inversion procedure a genetical algorithm (GA) was used. Specific features such as elitism, roulette-wheel process for selection operator and island theory were implemented. Optimization was based on the water content measurements recorded at several depths. Ten scenarios have been elaborated and applied on the two lysimeters in order to investigate the impact of the conceptual model in terms of processes description (mechanistic or compartmental) and geometry (number of horizons in the profile description) on the calibration accuracy. Calibration leads to a good agreement with the measured water contents. The most critical parameters for improving the goodness of fit are the number of horizons and the type of process description. Best fit are found for a mechanistic model with 5 horizons resulting in absolute differences between observed and simulated water contents less than 0.02 cm3cm-3 in average. Parameter estimate analysis shows that layers thicknesses are poorly constrained whereas hydraulic parameters are much well defined.

Schneider, Sbastien; Jacques, Diederik; Mallants, Dirk

2010-05-01

88

Top-of-atmosphere radiative fluxes - Validation of ERBE scanner inversion algorithm using Nimbus-7 ERB data  

NASA Technical Reports Server (NTRS)

The ERBE algorithm is applied to the Nimbus-7 earth radiation budget (ERB) scanner data for June 1979 to analyze the performance of an inversion method in deriving top-of-atmosphere albedos and longwave radiative fluxes. The performance is assessed by comparing ERBE algorithm results with appropriate results derived using the sorting-by-angular-bins (SAB) method, the ERB MATRIX algorithm, and the 'new-cloud ERB' (NCLE) algorithm. Comparisons are made for top-of-atmosphere albedos, longwave fluxes, viewing zenith-angle dependence of derived albedos and longwave fluxes, and cloud fractional coverage. Using the SAB method as a reference, the rms accuracy of monthly average ERBE-derived results are estimated to be 0.0165 (5.6 W/sq m) for albedos (shortwave fluxes) and 3.0 W/sq m for longwave fluxes. The ERBE-derived results were found to depend systematically on the viewing zenith angle, varying from near nadir to near the limb by about 10 percent for albedos and by 6-7 percent for longwave fluxes. Analyses indicated that the ERBE angular models are the most likely source of the systematic angular dependences. Comparison of the ERBE-derived cloud fractions, based on a maximum-likelihood estimation method, with results from the NCLE showed agreement within about 10 percent.

Suttles, John T.; Wielicki, Bruce A.; Vemury, Sastri

1992-01-01

89

Assessment of Polarization Effect on Efficiency of Levenberg-Marquardt Algorithm in Case of Thin Atmosphere over Black Surface  

NASA Astrophysics Data System (ADS)

The Levenberg-Marquardt algorithm [1, 2] provides a numerical iterative solution to the problem of minimization of a function over a space of its parameters. In our work, the Levenberg-Marquardt algorithm retrieves optical parameters of a thin (single scattering) plane parallel atmosphere irradiated by collimated infinitely wide monochromatic beam of light. Black ground surface is assumed. Computational accuracy, sensitivity to the initial guess and the presence of noise in the signal, and other properties of the algorithm are investigated in scalar (using intensity only) and vector (including polarization) modes. We consider an atmosphere that contains a mixture of coarse and fine fractions. Following [3], the fractions are simulated using Henyey-Greenstein model. Though not realistic, this assumption is very convenient for tests [4, p.354]. In our case it yields analytical evaluation of Jacobian matrix. Assuming the MISR geometry of observation [5] as an example, the average scattering cosines and the ratio of coarse and fine fractions, the atmosphere optical depth, and the single scattering albedo, are the five parameters to be determined numerically. In our implementation of the algorithm, the system of five linear equations is solved using the fast Cramer's rule [6]. A simple subroutine developed by the authors, makes the algorithm independent from external libraries. All Fortran 90/95 codes discussed in the presentation will be available immediately after the meeting from sergey.v.korkin@nasa.gov by request. [1]. Levenberg K, A method for the solution of certain non-linear problems in least squares, Quarterly of Applied Mathematics, 1944, V.2, P.164-168. [2]. Marquardt D, An algorithm for least-squares estimation of nonlinear parameters, Journal on Applied Mathematics, 1963, V.11, N.2, P.431-441. [3]. Hovenier JW, Multiple scattering of polarized light in planetary atmospheres. Astronomy and Astrophysics, 1971, V.13, P.7 - 29. [4]. Mishchenko MI, Travis LD, and Lacis AA, Multiple scattering of light by particles, Cambridge: University Press, 2006. [5]. http://www-misr.jpl.nasa.gov/Mission/misrInstrument/ [6]. Habgood K, Arel I, Revisiting Cramer's rule for solving dense linear systems, In: Proceedings of the 2010 Spring Simulation Multiconference, Paper No 82. ISBN: 978-1-4503-0069-8. DOI: 10.1145/1878537.1878623.

Korkin, S.; Lyapustin, A.

2012-12-01

90

Atmospheric Correction, Vicarious Calibration and Development of Algorithms for Quantifying Cyanobacteria Blooms from Oceansat-1 OCM Satellite Data  

NASA Astrophysics Data System (ADS)

Cyanobacteria represent a major harmful algal group in fresh to brackish water environments. Lac des Allemands, a freshwater lake located southwest of New Orleans, Louisiana on the upper end of the Barataria Estuary, provides a natural laboratory for remote characterization of cyanobacteria blooms because of their seasonal occurrence. The Ocean Colour Monitor (OCM) sensor provides radiance measurements similar to SeaWiFS but with higher spatial resolution. However, OCM does not have a standard atmospheric correction procedure, and it is difficult to find a detailed description of the entire atmospheric correction procedure for ocean (or lake) in one place. Atmospheric correction of satellite data over small lakes and estuaries (Case 2 waters) is also challenging due to difficulties in estimation of aerosol scattering accurately in these areas. Therefore, an atmospheric correction procedure was written for processing OCM data, based on the extensive work done for SeaWiFS. Since OCM-retrieved radiances were abnormally low in the blue wavelength region, a vicarious calibration procedure was also developed. Empirical inversion algorithms were developed to convert the OCM remote sensing reflectance (Rrs) at bands centered at 510.6 and 556.4 nm to concentrations of phycocyanin (PC), the primary cyanobacterial pigment. A holistic approach was followed to minimize the influence of other optically active constituents on the PC algorithm. Similarly, empirical algorithms to estimate chlorophyll a (Chl a) concentrations were developed using OCM bands centered at 556.4 and 669 nm. The best PC algorithm (R2=0.7450, p<0.0001, n=72) yielded a root mean square error (RMSE) of 36.92 ?g/L with a relative RMSE of 10.27% (PC from 2.75-363.50 ?g/L, n=48). The best algorithm for Chl a (R2=0.7510, p<0.0001, n=72) produced an RMSE of 31.19 ?g/L with a relative RMSE of 16.56% (Chl a from 9.46-212.76 ?g/L, n=48). While more field data are required to further validate the long-term performance of the algorithms, currently they represent the best protocol for establishing a long time-series of cyanobacterial blooms in the Lac des Allemands using OCM data.

Dash, P.; Walker, N. D.; Mishra, D. R.; Hu, C.; D'Sa, E. J.; Pinckney, J. L.

2011-12-01

91

Comparison of atmospheric correction algorithms for the Coastal Zone Color Scanner  

NASA Technical Reports Server (NTRS)

Before Nimbus-7 Costal Zone Color Scanner (CZC) data can be used to distinguish between coastal water types, methods must be developed for the removal of spatial variations in aerosol path radiance. These can dominate radiance measurements made by the satellite. An assessment is presently made of the ability of four different algorithms to quantitatively remove haze effects; each was adapted for the extraction of the required scene-dependent parameters during an initial pass through the data set The CZCS correction algorithms considered are (1) the Gordon (1981, 1983) algorithm; (2) the Smith and Wilson (1981) iterative algorityhm; (3) the pseudooptical depth method; and (4) the residual component algorithm.

Tanis, F. J.; Jain, S. C.

1984-01-01

92

Improved methodology for surface and atmospheric soundings, error estimates, and quality control procedures: the atmospheric infrared sounder science team version-6 retrieval algorithm  

NASA Astrophysics Data System (ADS)

The atmospheric infrared sounder (AIRS) science team version-6 AIRS/advanced microwave sounding unit (AMSU) retrieval algorithm is now operational at the Goddard Data and Information Services Center (DISC). AIRS version-6 level-2 products are generated near real time at the Goddard DISC and all level-2 and level-3 products are available starting from September 2002. Some of the significant improvements in retrieval methodology contained in the version-6 retrieval algorithm compared to that previously used in version-5 are described. In particular, the AIRS science team made major improvements with regard to the algorithms used to (1) derive surface skin temperature and surface spectral emissivity; (2) generate the initial state used to start the cloud clearing and retrieval procedures; and (3) derive error estimates and use them for quality control. Significant improvements have also been made in the generation of cloud parameters. In addition to the basic AIRS/AMSU mode, version-6 also operates in an AIRS only (AO) mode, which produces results almost as good as those of the full AIRS/AMSU mode. The improvements of some AIRS version-6 and version-6 AO products compared to those obtained using version-5 are also demonstrated.

Susskind, Joel; Blaisdell, John M.; Iredell, Lena

2014-01-01

93

An improved algorithm for extracting atmospheric motion vectors in cloud-free region from FY-2E thermal infrared imagery  

NASA Astrophysics Data System (ADS)

Atmospheric motion vectors (AMV) in cloud-free region can not be obtained with current operational cloud-motion tracking and water-vapor channel algorithms. The motivation of this study is to introduce a supplementary algorithm in order to work out the low-level AMVs in the clear area with FY-2E long wave, window (10.3~11.5, 11.6~12.8 ?m) channel imagery. It has been shown that the weak signals indicating water vapor in "cloud-free region" can be extracted from FY-2E long wave infrared imagery and may be used as tracers for atmospheric motion vectors. The algorithm, named as Second Order difference method, has been raised in order to weaken the surface temperature interference to the weak signals of water vapor in "cloud-free region" by means of split window and temporal difference calculations. The results from theory analysis and cases study show that this method can make up for the wind data in regions lack of cloud but rich of water vapor and comparison between the wind vectors from this method and the NCEP reanalysis data shows a good consistency.

Wang, Zhenhui; Zhang, Qing; Tang, Min; Zhao, Hang; Yang, Lu; Zhan, Yizhe

2014-10-01

94

Atmospheric Sensitivity to Spectral Top-of-Atmosphere Solar Irradiance Perturbations, Using MODTRAN-5 Radiative Transfer Algorithm  

NASA Astrophysics Data System (ADS)

The opportunity to insert state-of-the-art solar irradiance measurements and calculations, with subtle perturbations, into a narrow spectral resolution radiative transfer model has recently been facilitated through release of MODTRAN-5 (MOD5). The new solar data are from: (1) SORCE satellite measurements of solar variability over solar rotation cycle, & (2) ultra-narrow calculation of a new solar source irradiance, extending over the full MOD5 spectral range, from 0.2 um to far-IR. MODTRAN-5, MODerate resolution radiance and TRANsmittance code, has been developed collaboratively by Air Force Research Laboratory and Spectral Sciences, Inc., with history dating back to LOWTRAN. It includes approximations for all local thermodynamic equilibrium terms associated with molecular, cloud, aerosol and surface components for emission, scattering, and reflectance, including multiple scattering, refraction and a statistical implementation of Correlated-k averaging. The band model is based on 0.1 cm-1 (also 1.0, 5.0 and 15.0 cm-1 statistical binning for line centers within the interval, captured through an exact formulation of the full Voigt line shape. Spectroscopic parameters are from HITRAN 2004 with user-defined options for additional gases. Recent validation studies show MOD5 replicates line-by-line brightness temperatures to within ~0.02K average and <1.0K RMS. MOD5 can then serve as a surrogate for a variety of perturbation studies, including the two modes for the solar source function, Io. (1) Data from the Solar Radiation and Climate Experiment (SORCE) satellite mission provide state-of-the-art measurements of UV, visible, near-IR, plus total solar radiation, on near real-time basis. These internally consistent estimates of Sun's output over solar rotation and longer time scales are valuable inputs for studying effects of Sun's radiation on Earth's atmosphere and climate. When solar rotation encounters bright plage and dark sunspots, relative variations are expected to be very small in visible wavelengths, although absolute power is substantial. SORCE's Spectral Irradiance Monitor measurements are readily included in comparative MOD5 calculations. (2) The embedded solar irradiance within MOD5 must be compatible with the chosen band model resolution binning. By matching resolutions some issues related to the correlated-k band model parameterizations can be tested. Two high resolution solar irradiances, the MOD5 default irradiance (Kurucz) and a new compilation associated with Solar Radiation Physical Modeling project (Fontenla), are compared to address the potential impact of discrepancies between any sets of irradiances. The magnitude of solar variability, as measured and calculated, can lead to subtle changes in heating/cooling rates throughout the atmosphere, as a function of altitude and wavelength. By holding chemical & dynamical responses constant, only controlled distributions of absorbing gases, aerosols and clouds will contribute to observed 1st order radiative effects.

Anderson, G.; Berk, A.; Harder, G.; Fontenla, J.; Shettle, E.; Pilewski, P.; Kindel, B.; Chetwynd, J.; Gardner, J.; Hoke, M.; Jordan, A.; Lockwood, R.; Felde, G.; Archarya, P.

2006-12-01

95

Retrieval of atmospheric CO2 from satellite near-infrared nadir spectra: inter-comparison of different algorithms  

NASA Astrophysics Data System (ADS)

Carbon dioxide is the most important anthropogenic greenhouse gas. Its global increasing concentration in the Earth's atmosphere is the main driver for global warming. However, in spite of its importance, there are still large uncertainties on its global sources and sinks. Satellite measurements, if accurate and precise enough, have the potential to reduce these surface flux uncertainties. At present, there are only two satellite instruments orbiting the Earth which are able to measure the CO2 mixing ratio (XCO2) with large sensitivity also in the boundary layer. These are SCIAMACHY (launched in 2002) and GOSAT (launched in 2009). Worldwide, several teams of scientists are developing algorithms aiming to meet the challenging user requirements. The majority of these groups take part in ESA's climate change initiative (CCI) on greenhouse gases (GHG) where there algorithms stand into competition. Within the presentation, recent inter-comparison results will be shown focusing on global SCIAMACHY nadir observations.

Reuter, M.; Buchwitz, M.; Schneising, O.; Heymann, J.; Bovensmann, H.; Burrows, J. P.

2012-04-01

96

Middle atmosphere project: A radiative heating and cooling algorithm for a numerical model of the large scale stratospheric circulation  

NASA Technical Reports Server (NTRS)

A Curtis matrix is used to compute cooling by the 15 micron and 10 micron bands of carbon dioxide. Escape of radiation to space and exchange the lower boundary are used for the 9.6 micron band of ozone. Voigt line shape, vibrational relaxation, line overlap, and the temperature dependence of line strength distributions and transmission functions are incorporated into the Curtis matrices. The distributions of the atmospheric constituents included in the algorithm, and the method used to compute the Curtis matrices are discussed as well as cooling or heating by the 9.6 micron band of ozone. The FORTRAN programs and subroutines that were developed are described and listed.

Wehrbein, W. M.; Leovy, C. B.

1981-01-01

97

Work unit compensation.  

PubMed

The author describes an innovative "work unit compensation" system that acts as an adjunct to existing personnel payment structures. The process, developed as a win-win alternative for both employees and their institution, includes a reward system for the entire department and insures a team atmosphere. The Community Medical Center in Toms River, New Jersey developed the plan which sets the four basic goals: to be fair, economical, lasting and transferable (FELT). The plan has proven to be a useful tool in retention and recruitment of qualified personnel. PMID:10111054

Sodano, M J

1991-01-01

98

Simultaneous Retrieval of Temperature, Water Vapor and Ozone Atmospheric Profiles from IASI: Compression, De-noising, First Guess Retrieval and Inversion Algorithms  

NASA Technical Reports Server (NTRS)

A fast temperature water vapor and ozone atmospheric profile retrieval algorithm is developed for the high spectral resolution Infrared Atmospheric Sounding Interferometer (IASI) space-borne instrument. Compression and de-noising of IASI observations are performed using Principal Component Analysis. This preprocessing methodology also allows, for a fast pattern recognition in a climatological data set to obtain a first guess. Then, a neural network using first guess information is developed to retrieve simultaneously temperature, water vapor and ozone atmospheric profiles. The performance of the resulting fast and accurate inverse model is evaluated with a large diversified data set of radiosondes atmospheres including rare events.

Aires, F.; Rossow, W. B.; Scott, N. A.; Chedin, A.; Hansen, James E. (Technical Monitor)

2001-01-01

99

Atmospheres  

NASA Astrophysics Data System (ADS)

When high Al containing Fe alloys such as TRIP steels are exposed to atmospheres that contain N2 during re-heating, sub-surface nitrides form and these can be detrimental to mechanical properties. Nitride precipitation can be controlled by minimizing the access of the gaseous atmosphere to the metal surface, which can be achieved by a rapid growth of a continuous and adherent surface scale. This investigation utilizes a Au-image furnace attached to a confocal scanning microscope to simulate the annealing temperature vs time while Fe-Al alloys (with Al contents varying from 1 to 8 wt pct) are exposed to a O2-N2 atm with 10-6 atm O2. The heating times of 1, 10, and 100 minutes to the isothermal temperature of 1558 K (1285 C) were used. It was found that fewer sub-surface nitride precipitates formed when the heating time was lowered and when Al content in the samples was increased. In the 8 wt pct samples, no internal nitride precipitates were present regardless of heating time. In the 3 and 5 wt pct samples, internal nitride precipitates were nearly more or less absent at heating times less than 10 minutes. The decrease in internal precipitates was governed by the evolving structure of the external oxide-scale. At low heating rates and/or low Al contents, significant Fe-oxide patches formed and these appeared to allow for ingress of gaseous N2. For the slow heating rates, ingress could have happened during the longer time spent in lower temperatures where non-protective alumina was present. As Al content in the alloy was increased, the external scale was Al2O3 and/or FeAl2O4 and more continuous and consequently hindered the N2 from accessing the metal surface. Increasing the Al content in the alloy had the effect of promoting the outward diffusion of Al in the alloy and thereby assisting the formation of the continuous external layer of Al2O3 and/or FeAl2O4.

Bott, June; Yin, Hongbin; Sridhar, Seetharaman

2014-12-01

100

Atmospheric Turbulence Compensation of Point Source Images Using Asynchronous Stochastic Parallel Gradient Descent Technique on AMOS 3.6m Telescope  

NASA Astrophysics Data System (ADS)

Stochastic Parallel Gradient Descent Technique-based Adaptive Optics (SPGD-AO) system described in this presentation doesn't use conventional wave front sensor. It uses a metric signal collected by a single pixel detector placed behind a pinhole in the image plane to drive three deformable mirrors (DMs). The system is designed to compensate the image for turbulence effects. The theory behind this method is described in detail in J. Opt. Soc. Ame. A, 15,2745-2758,1998. However, this technique, while widely simulated and tested, was not verified so far in astronomical field site experiments. During the month of May 2007, a series of experiments using SPGD-AO compensation on stars at several elevation angles and turbulence levels, were conducted successfully at US Air Force Maui Optical and Supercomputing Site (AMOS) using 3.6 m telescope. Some of the results of these experiments will be described. This is the first time SPGD-AO systems have been tested and verified in astronomical field site experiments.

Voronstov, M.; Riker, J.; Carhart, G.; Gudimetla, V.; Berensev, L.; Weyrauch, T.

101

A simple algorithm to estimate the effective regional atmospheric parameters for thermal-inertia mapping  

USGS Publications Warehouse

A method based solely on remote sensing data has been developed to estimate those meteorological effects which are required for thermal-inertia mapping. It assumes that the atmospheric fluxes are spatially invariant and that the solar, sky, and sensible heat fluxes can be approximated by a simple mathematical form. Coefficients are determined from least-squares method by fitting observational data to our thermal model. A comparison between field measurements and the model-derived flux shows the type of agreement which can be achieved. An analysis of the limitations of the method is also provided. ?? 1981.

Watson, K.; Hummer-Miller, S.

1981-01-01

102

Atmospheric Correction of Ocean Color Imagery: Test of the Spectral Optimization Algorithm with the Sea-Viewing Wide Field-of-View Sensor  

Microsoft Academic Search

We implemented the spectral optimization algorithm [SOA; Appl. Opt. 37, 5560 (1998) in an image-processing] environment and tested it with Sea-viewing Wide Field-of-View Sensor (SeaWiFS) imagery from the Middle Atlantic Bight and the Sargasso Sea. We compared the SOA and the standard SeaWiFS algorithm on two days that had significantly different atmospheric turbidities but, because of the location and time

Roman M. Chomko; Howard R. Gordon

2001-01-01

103

Improved Determination of Surface and Atmospheric Temperatures Using Only Shortwave AIRS Channels: The AIRS Version 6 Retrieval Algorithm  

NASA Technical Reports Server (NTRS)

AIRS was launched on EOS Aqua on May 4, 2002 together with ASMU-A and HSB to form a next generation polar orbiting infrared and microwave atmosphere sounding system (Pagano et al 2003). The theoretical approach used to analyze AIRS/AMSU/HSB data in the presence of clouds in the AIRS Science Team Version 3 at-launch algorithm, and that used in the Version 4 post-launch algorithm, have been published previously. Significant theoretical and practical improvements have been made in the analysis of AIRS/AMSU data since the Version 4 algorithm. Most of these have already been incorporated in the AIRS Science Team Version 5 algorithm (Susskind et al 2010), now being used operationally at the Goddard DISC. The AIRS Version 5 retrieval algorithm contains three significant improvements over Version 4. Improved physics in Version 5 allowed for use of AIRS clear column radiances (R(sub i)) in the entire 4.3 micron CO2 absorption band in the retrieval of temperature profiles T(p) during both day and night. Tropospheric sounding 15 micron CO2 observations were used primarily in the generation of clear column radiances (R(sub i)) for all channels. This new approach allowed for the generation of accurate Quality Controlled values of R(sub i) and T(p) under more stressing cloud conditions. Secondly, Version 5 contained a new methodology to provide accurate case-by-case error estimates for retrieved geophysical parameters and for channel-by-channel clear column radiances. Thresholds of these error estimates are used in a new approach for Quality Control. Finally, Version 5 contained for the first time an approach to provide AIRS soundings in partially cloudy conditions that does not require use of any microwave data. This new AIRS Only sounding methodology was developed as a backup to AIRS Version 5 should the AMSU-A instrument fail. Susskind et al 2010 shows that Version 5 AIRS Only sounding are only slightly degraded from the AIRS/AMSU soundings, even at large fractional cloud cover.

Susskind, Joel; Blaisdell, John; Iredell, Lena

2010-01-01

104

A parallel hybrid numerical algorithm for simulating gas flow and gas discharge of an atmospheric-pressure plasma jet  

NASA Astrophysics Data System (ADS)

Development of a hybrid numerical algorithm which couples weakly with the gas flow model (GFM) and the plasma fluid model (PFM) for simulating an atmospheric-pressure plasma jet (APPJ) and its acceleration by two approaches is presented. The weak coupling between gas flow and discharge is introduced by transferring between the results obtained from the steady-state solution of the GFM and cycle-averaged solution of the PFM respectively. Approaches of reducing the overall runtime include parallel computing of the GFM and the PFM solvers, and employing a temporal multi-scale method (TMSM) for PFM. Parallel computing of both solvers is realized using the domain decomposition method with the message passing interface (MPI) on distributed-memory machines. The TMSM considers only chemical reactions by ignoring the transport terms when integrating temporally the continuity equations of heavy species at each time step, and then the transport terms are restored only at an interval of time marching steps. The total reduction of runtime is 47% by applying the TMSM to the APPJ example presented in this study. Application of the proposed hybrid algorithm is demonstrated by simulating a parallel-plate helium APPJ impinging onto a substrate, which the cycle-averaged properties of the 200th cycle are presented. The distribution patterns of species densities are strongly correlated by the background gas flow pattern, which shows that consideration of gas flow in APPJ simulations is critical.

Lin, K.-M.; Hu, M.-H.; Hung, C.-T.; Wu, J.-S.; Hwang, F.-N.; Chen, Y.-S.; Cheng, G.

2012-12-01

105

Compensation Planning Office of Human Resources, Compensation  

E-print Network

for specific job duties. Narrow classification definitions. Narrow (pay) ranges. Minimal Avenue Columbus, OH 43210 Phone: (614) 292-4037, Fax: (614) 292-0549 E-mail: compensation@hr.osu.edu #12: (614) 292-0549, compensation@hr.osu.edu http://hr.osu.edu revised 5/2004 Handbook for Compensation

106

Methane emissions from tropical wetlands in LPX: Algorithm development and validation using atmospheric measurements  

NASA Astrophysics Data System (ADS)

Tropical wetlands are an important and highly uncertain term in the global budget of methane. Unlike wetlands in higher latitudes, which are dominated by water logged peatlands, tropical wetlands consist primarily of inundated river floodplains responding seasonally to variations in river discharge. Despite the fact that the hydrology of these systems is obviously very different, process models used for estimating methane emissions from wetlands commonly lack a dedicated parameterization for the tropics. This study is a first attempt to develop such a parameterization for use in the global dynamical vegetation model LPX. The required floodplain extents and water depth are calculated offline using the global hydrological model PCR-GLOBWB, which includes a sophisticated river routing scheme. LPX itself has been extended with a dedicated floodplain land unit and flood tolerant PFTs. The simulated species competition and productivity have been verified using GLC2000 and MODIS, pointing to directions for further model improvement regarding vegetation dynamics and hydrology. LPX simulated methane fluxes have been compared with available in situ measurements from tropical America. Finally, estimates for the Amazon basin have been implemented in the TM5 atmospheric transport model and compared with aircraft measured vertical profiles. The first results that will be presented demonstrate that, despite the limited availability of measurements, useful constraints on the magnitude and seasonality of Amazonian methane emissions can be derived.

Houweling, S.; Ringeval, B.; Basu, A.; Van Beek, L. P.; Van Bodegom, P.; Spahni, R.; Gatti, L.; Gloor, M.; Roeckmann, T.

2013-12-01

107

Hyperspectral material identification on radiance data using single-atmosphere or multiple-atmosphere modeling  

NASA Astrophysics Data System (ADS)

Reflectance-domain methods convert hyperspectral data from radiance to reflectance using an atmospheric compensation model. Material detection and identification are performed by comparing the compensated data to target reflectance spectra. We introduce two radiance-domain approaches, Single atmosphere Adaptive Cosine Estimator (SACE) and Multiple atmosphere ACE (MACE) in which the target reflectance spectra are instead converted into sensor-reaching radiance using physics-based models. For SACE, known illumination and atmospheric conditions are incorporated in a single atmospheric model. For MACE the conditions are unknown so the algorithm uses many atmospheric models to cover the range of environmental variability, and it approximates the result using a subspace model. This approach is sometimes called the invariant method, and requires the choice of a subspace dimension for the model. We compare these two radiance-domain approaches to a Reflectance-domain ACE (RACE) approach on a HYDICE image featuring concealed materials. All three algorithms use the ACE detector, and all three techniques are able to detect most of the hidden materials in the imagery. For MACE we observe a strong dependence on the choice of the material subspace dimension. Increasing this value can lead to a decline in performance.

Mariano, Adrian V.; Grossmann, John M.

2010-11-01

108

Radiation Exposure Compensation Program  

NSDL National Science Digital Library

This is the Justice Department's Radiation Exposure Compensation Program homepage. This site features information about the Radiation Exposure Compensation Act, including claimant categories, claim forms, and the Energy Employees Occupational Illness Compensation Program Act. This site also provides a table illustrating a summary of all claims received and compensation paid to date.

U.S. Department of Justice Radiation Exposure Compensation Program

109

Reactive power compensating system  

DOEpatents

The reactive power of an induction machine is compensated by providing fixed capacitors on each phase line for the minimum compensation required, sensing the current on one line at the time its voltage crosses zero to determine the actual compensation required for each phase, and selecting switched capacitors on each line to provide the balance of the compensation required.

Williams, Timothy J. (Redondo Beach, CA); El-Sharkawi, Mohamed A. (Renton, WA); Venkata, Subrahmanyam S. (Seattle, WA)

1987-01-01

110

Hybrid algorithm of minimum relative entropy-particle swarm optimization with adjustment parameters for gas source term identification in atmosphere  

NASA Astrophysics Data System (ADS)

In order to identify the source term of gas emission in atmosphere, an improved hybrid algorithm combined with the minimum relative entropy (MRE) and particle swarm optimization (PSO) method was presented. Not only are the estimated source parameters obtained, but also the confidence intervals at some probability levels. If only the source strength was required to be determined, the problem can be viewed as a linear inverse problem directly, which can be solved by original MRE method successfully. When both source strength and location are unknown, the common gas dispersion model should be transformed to be a linear system. Although the transformed linear model has some differences from that in original MRE method, satisfied estimation results were still obtained by adding iteratively adaptive adjustment parameters in the MRE-PSO method. The dependence of the MRE-PSO method on prior information such as lower and upper bound, prior expected values and noises were also discussed. The results showed that the confidence intervals and estimated parameters are influenced little by the prior bounds and expected values, but the errors affect the estimation results greatly. The simulation and experiment verification results showed that the MRE-PSO method is able to identify the source parameters with satisfied results. Finally, the error model was probed and then it was added in the MRE-PSO method. The addition of error model improves the performance of the identification method. Therefore, the MRE-PSO method with adjustment parameters proposed in this paper is a potential good method to resolve inverse problem in atmosphere environment.

Ma, Denglong; Wang, Simin; Zhang, Zaoxiao

2014-09-01

111

Atmospheric Correction of Ocean Color Imagery: Test of the Spectral Optimization Algorithm with the Sea-Viewing Wide Field-of-View Sensor.  

PubMed

We implemented the spectral optimization algorithm [SOA; Appl. Opt. 37, 5560 (1998)] in an image-processing environment and tested it with Sea-viewing Wide Field-of-View Sensor (SeaWiFS) imagery from the Middle Atlantic Bight and the Sargasso Sea. We compared the SOA and the standard SeaWiFS algorithm on two days that had significantly different atmospheric turbidities but, because of the location and time of the year, nearly the same water properties. The SOA-derived pigment concentration showed excellent continuity over the two days, with the relative difference in pigments exceeding 10% only in regions that are characteristic of high advection. The continuity in the derived water-leaving radiances at 443 and 555 nm was also within ~10%. There was no obvious correlation between the relative differences in pigments and the aerosol concentration. In contrast, standard processing showed poor continuity in derived pigments over the two days, with the relative differences correlating strongly with atmospheric turbidity. SOA-derived atmospheric parameters suggested that the retrieved ocean and atmospheric reflectances were decoupled on the more turbid day. On the clearer day, for which the aerosol concentration was so low that relatively large changes in aerosol properties resulted in only small changes in aerosol reflectance, water patterns were evident in the aerosol properties. This result implies that SOA-derived atmospheric parameters cannot be accurate in extremely clear atmospheres. PMID:18357315

Chomko, R M; Gordon, H R

2001-06-20

112

Atmospheric Correction of Ocean Color Imagery: Test of the Spectral Optimization Algorithm with the Sea-Viewing Wide Field-of-View Sensor  

NASA Astrophysics Data System (ADS)

We implemented the spectral optimization algorithm [SOA; Appl. Opt. 37, 5560 (1998) in an image-processing] environment and tested it with Sea-viewing Wide Field-of-View Sensor (SeaWiFS) imagery from the Middle Atlantic Bight and the Sargasso Sea. We compared the SOA and the standard SeaWiFS algorithm on two days that had significantly different atmospheric turbidities but, because of the location and time of the year, nearly the same water properties. The SOA-derived pigment concentration showed excellent continuity over the two days, with the relative difference in pigments exceeding 10% only in regions that are characteristic of high advection. The continuity in the derived water-leaving radiances at 443 and 555 nm was also within ~10%. There was no obvious correlation between the relative differences in pigments and the aerosol concentration. In contrast, standard processing showed poor continuity in derived pigments over the two days, with the relative differences correlating strongly with atmospheric turbidity. SOA-derived atmospheric parameters suggested that the retrieved ocean and atmospheric reflectances were decoupled on the more turbid day. On the clearer day, for which the aerosol concentration was so low that relatively large changes in aerosol properties resulted in only small changes in aerosol reflectance, water patterns were evident in the aerosol properties. This result implies that SOA-derived atmospheric parameters cannot be accurate in extremely clear atmospheres.

Chomko, Roman M.; Gordon, Howard R.

2001-06-01

113

Compensator improvement for multivariable control systems  

NASA Technical Reports Server (NTRS)

A theory and the associated numerical technique are developed for an iterative design improvement of the compensation for linear, time-invariant control systems with multiple inputs and multiple outputs. A strict constraint algorithm is used in obtaining a solution of the specified constraints of the control design. The result of the research effort is the multiple input, multiple output Compensator Improvement Program (CIP). The objective of the Compensator Improvement Program is to modify in an iterative manner the free parameters of the dynamic compensation matrix so that the system satisfies frequency domain specifications. In this exposition, the underlying principles of the multivariable CIP algorithm are presented and the practical utility of the program is illustrated with space vehicle related examples.

Mitchell, J. R.; Mcdaniel, W. L., Jr.; Gresham, L. L.

1977-01-01

114

Power Factor Compensation (PFC) Power Factor Compensation  

E-print Network

Power Factor Compensation (PFC) Power Factor Compensation The power factor (PF) is defined as the ratio between the active power and the apparent power of a system. If the current and voltage are periodic with period , and [ ), then the active power is defined by ( ) ( ) (their inner product

Knobloch,Jürgen

115

Impacts of the Convective Transport Algorithm on Atmospheric Composition and Ozone-Climate Feedbacks in GEOS-CCM  

NASA Technical Reports Server (NTRS)

Convective transport is one of the dominant factors in determining the composition of the troposphere. It is the main mechanism for lofting constituents from near-surface source regions to the middle and upper troposphere, where they can subsequently be advected over large distances. Gases reaching the upper troposphere can also be injected through the tropopause and play a subsequent role in the lower stratospheric ozone balance. Convection codes in climate models remain a great source of uncertainty for both the energy balance of the general circulation and the transport of constituents. This study uses the Goddard Earth Observing System Chemistry-Climate Model (GEOS CCM) to perform a controlled experiment that isolates the impact of convective transport of constituents from the direct changes on the atmospheric energy balance. Two multi-year simulations are conducted. In the first, the thermodynamic variable, moisture, and all trace gases are transported using the multi-plume Relaxed-Arakawa-Schubert (RAS) convective parameterization. In the second simulation, RAS impacts the thermodynamic energy and moisture in this standard manner, but all other constituents are transported differently. The accumulated convective mass fluxes (including entrainment and detrainment) computed at each time step of the GCM are used with a diffusive (bulk) algorithm for the vertical transport, which above all is less efficient at transporting constituents from the lower to the upper troposphere. Initial results show the expected differences in vertical structure of trace gases such as carbon monoxide, but also show differences in lower stratospheric ozone, in a region where it can potentially impact the climate state of the model. This work will investigate in more detail the impact of convective transport changes by comparing the two simulations over many years (1996-2010), focusing on comparisons with observed constituent distributions and similarities and differences of patterns of inter-annual variability caused by the convective transport algorithm. In particular, the impact on lower stratospheric composition will be isolated and the subsequent feedbacks of ozone on the climate forcing and tropopause structure will be assessed.

Pawson, S.; Nielsen, Jon E.; Oman, L.; Douglass, A. R.; Duncan, B. N.; Zhu, Z.

2012-01-01

116

75 FR 48274 - Radiation Exposure Compensation Act: Allowance for Costs and Expenses  

Federal Register 2010, 2011, 2012, 2013, 2014

...claims pending with the Radiation Exposure Compensation Act...1990, Congress passed the Radiation Exposure Compensation Act...diseases following exposure to radiation released during above-ground atmospheric nuclear weapons tests or...

2010-08-10

117

Ecomp Executive Compensation Database  

NSDL National Science Digital Library

The Ecomp Executive Compensation Database allows users to research the compensation and net-worth of executives. Users may search the database by company name or ticker symbol, as well as by state, sector, and industry pull-down menus. Search returns list compensation summaries for the top executives, including salary, bonus, and total compensation. Clicking on the executive's name will give a more detailed summary, including restricted stock, LTIP payouts, and value realized for options exercised. All numbers are for 1999.

118

Ground based measurements on reflectance towards validating atmospheric correction algorithms on IRS-P6 AWiFS data  

Microsoft Academic Search

In Earth observation, the atmosphere has a non-negligible influence on the visible and infrared radiation which is strong enough to modify the reflected electromagnetic signal and at-target reflectance. Scattering of solar irradiance by atmospheric molecules and aerosol generates path radiance, which increases the apparent surface reflectance over dark surfaces while absorption by aerosols and other molecules in the atmosphere causes

Anu Rani Sharma; Shailesh Kumar Kharol; Badarinath Kvs; P. S. Roy

2010-01-01

119

Application of a digital non-linear compensation algorithm for evaluating the performance of root-raised-cosine pulses in 112 Gbit s-1 DP-QPSK transmission  

NASA Astrophysics Data System (ADS)

In this paper, we numerically investigate the non-linear tolerance of root-raised-cosine (RRC) pulse shaping by interpolating finite impulse response (FIR) filters in conjunction with digital backward propagation (DBP) in coherent 112 Gbit s-1 dual-polarization quadrature phase shift keying (DP-QPSK) transmission. The results depict that RRC pulses are more tolerant to intra-channel non-linearities, i.e. self-phase modulation (SPM), as compared to standard RZ-33 and NRZ pulses. The non-linear threshold point is improved by using RRC pulses by a factor of 2 dB signal input power as compared to RZ pulses and by 4 dB signal launch power as compared to NRZ pulses. The behavior of RRC pulses is also investigated with standard single mode fiber (SMF), non-zero dispersion shifted fiber (NZDSF) and next-generation large Aeff pure silica core fiber (LA-PSCF). Most importantly multi-span DBP is implemented and in the case of RRC pulses the computational efforts of the conventional DBP algorithm are reduced by 80% with a diminutive Q-penalty of 0.74 dB. The duty cycle of the RRC pulses is further optimized for efficient system performance. We have also compared the performance of single-channel transmission with the multi-channel transmission, where the performance is limited due to inter-channel non-linear effects. Furthermore, the non-linear tolerance of RRC pulses is investigated with; (a) different amplifier spacing and (b) variation in transmission link design information for the DBP algorithm.

Asif, Rameez; Usman, Muhammad; Lin, Chien-Yu; Schmauss, Bernhard

2012-09-01

120

Practical Atmospheric Correction Algorithms for a Multi-Spectral Sensor From the Visible Through the Thermal Spectral Regions  

SciTech Connect

Deriving information about the Earth's surface requires atmospheric corrections of the measured top-of-the-atmosphere radiances. One possible path is to use atmospheric radiative transfer codes to predict how the radiance leaving the ground is affected by the scattering and attenuation. In practice the atmosphere is usually not well known and thus it is necessary to use more practical methods. The authors will describe how to find dark surfaces, estimate the atmospheric optical depth, estimate path radiance and identify thick clouds using thresholds on reflectance and NDVI and columnar water vapor. The authors describe a simple method to correct a visible channel contaminated by a thin cirrus clouds.

Borel, C.C.; Villeneuve, P.V.; Clodium, W.B.; Szymenski, J.J.; Davis, A.B.

1999-04-04

121

Frequency compensation in an adaptive antenna system for frequency-hopping communications  

Microsoft Academic Search

For the full exploitation of an adaptive antenna system for wideband frequency-hopping communicatioms, some form of frequency compensation is necessary. Parameter-dependent, spectral, and anticipative processing are the three methods of frequency compensation that are examined; their strengths, limitations, and variations are discussed. The underlying adaptive algorithm is the Maximin algorithm, which has major advantages compared with other algorithms.

Don Torrieri; Kesh Bakhru

1987-01-01

122

Improved air-sea flux algorithms in an ocean-atmosphere coupled model for simulation of global ocean SST and its tropical Pacific variability  

NASA Astrophysics Data System (ADS)

A revised algorithm for air-sea exchange parameterization of momentum, sensible and latent heat flux improves the climate simulation of the global distribution of sea surface temperature (SST) and tropical Pacific variability of SST. Based upon an analysis of studies from field programs, we apply the revised algorithm with new expressions for surface momentum and scalar roughness length dependent on 10-m winds in neutral condition, and evaluate them in the ocean-atmosphere coupled model of the Australian Community Climate and Earth-System Simulator. The revised algorithm improves simulations for mean global SST distribution, demonstrated with Pearson's correlation indices showing corrections to a net fraction of 28 % over the global oceans. Being focused on the tropical Pacific, the algorithm eases the tropical SST cold tongue bias, and improves predictability of ENSO variability with better representations of the standard deviation of the Nino-3.4 index, especially the skewness of the index for nonlinearity of ENSO variability. Bjerknes and thermodynamical feedbacks are applied to understand the effects of the revised algorithm on the predictability of the Nino indices.

Ma, Yimin; Zhou, Xiaobing; Bi, Daohua; Sun, Zhian; Hirst, Anthony C.

2015-03-01

123

Improved air-sea flux algorithms in an ocean-atmosphere coupled model for simulation of global ocean SST and its tropical Pacific variability  

NASA Astrophysics Data System (ADS)

A revised algorithm for air-sea exchange parameterization of momentum, sensible and latent heat flux improves the climate simulation of the global distribution of sea surface temperature (SST) and tropical Pacific variability of SST. Based upon an analysis of studies from field programs, we apply the revised algorithm with new expressions for surface momentum and scalar roughness length dependent on 10-m winds in neutral condition, and evaluate them in the ocean-atmosphere coupled model of the Australian Community Climate and Earth-System Simulator. The revised algorithm improves simulations for mean global SST distribution, demonstrated with Pearson's correlation indices showing corrections to a net fraction of 28 % over the global oceans. Being focused on the tropical Pacific, the algorithm eases the tropical SST cold tongue bias, and improves predictability of ENSO variability with better representations of the standard deviation of the Nino-3.4 index, especially the skewness of the index for nonlinearity of ENSO variability. Bjerknes and thermodynamical feedbacks are applied to understand the effects of the revised algorithm on the predictability of the Nino indices.

Ma, Yimin; Zhou, Xiaobing; Bi, Daohua; Sun, Zhian; Hirst, Anthony C.

2014-08-01

124

MOTION COMPENSATION OF INTERFEROMETRIC SYNTHETIC APERTURE RADAR  

E-print Network

reference track, coupled with the current lower-order motion compensation algorithm. Attitude variations to a single track has two effects. First, the applied MOCO phase corrections remove the "flat-earth" #12 and continual support. Finally, and most importantly, I want to thank God for having given me the opportunity

Long, David G.

125

Construction of an Eulerian atmospheric dispersion model based on the advection algorithm of M. Galperin: dynamic cores v.4 and 5 of SILAM v.5.5  

NASA Astrophysics Data System (ADS)

The paper presents dynamic cores v.4 and v.5 of the System for Integrated modeLling of Atmospheric coMposition SILAM v.5.5 based on the advection algorithm of Michael Galperin. This advection routine, so far weakly presented in international literature, is non-diffusive, positively defined, stable with regard to Courant number significantly above one, and very efficient computationally. For the first time, we present a rigorous description of its original version, along with several updates that improve its monotonicity and allow applications to long-living species in conditions of complex atmospheric flows. The other extension allows the scheme application to dynamics of aerosol spectra. The scheme is accompanied with the previously developed vertical diffusion algorithm, which encapsulates the dry deposition process as a boundary condition. Connection to chemical transformation modules is outlined, accounting for the specifics of transport scheme. Quality of the advection routine is evaluated using a large set of tests. The original approach has been previously compared with several classic algorithms widely used in operational models. The basic tests were repeated for the updated scheme, along with demanding global 2-D tests recently suggested in literature, which allowed positioning the scheme with regard to sophisticated state-of-the-art approaches. The model performance appeared close to the top of the list with very modest computational costs.

Sofiev, M.; Vira, J.; Kouznetsov, R.; Prank, M.; Soares, J.; Genikhovich, E.

2015-03-01

126

Robust springback compensation  

NASA Astrophysics Data System (ADS)

Springback simulation and springback compensation are more and more applied in productive use of die engineering. In order to successfully compensate a tool accurate springback results are needed as well as an effective compensation approach. In this paper a methodology has been introduce in order to effectively compensate tools. First step is the full process simulation meaning that not only the drawing operation will be simulated but also all secondary operations like trimming and flanging. Second will be the verification whether the process is robust meaning that it obtains repeatable results. In order to effectively compensate a minimum clamping concept will be defined. Once these preconditions are fulfilled the tools can be compensated effectively.

Carleer, Bart; Grimm, Peter

2013-12-01

127

Loss-compensated radiometer  

SciTech Connect

A new radiometer concept is described and evaluated. Automatic dynamic electrical compensation is achieved by a high-gain feedback amplifier and low thermal inertia solar and compensating electrical sensors. With sufficiently high gain, compensation can increase accuracy to limits determined by amplifier drift. Equations governing instrument response are derived and analyzed. Initial measurements on a preliminary prototype confirm the validity of the concept which should yield a very accurate instrument with ''self calibrating'' features.

Lobo, P.C.

1984-05-01

128

Results of the Compensated Earth-Moon-Earth Retroreflector Laser Link (CEMERLL) Experiment  

NASA Technical Reports Server (NTRS)

Adaptive optics techniques can be used to realize a robust low bit-error-rate link by mitigating the atmosphere-induced signal fades in optical communications links between ground-based transmitters and deep-space probes. Phase I of the Compensated Earth-Moon-Earth Retroreflector Laser Link (CEMERLL) experiment demonstrated the first propagation of an atmosphere-compensated laser beam to the lunar retroreflectors. A 1.06-micron Nd:YAG laser beam was propagated through the full aperture of the 1.5-m telescope at the Starfire Optical Range (SOR), Kirtland Air Force Base, New Mexico, to the Apollo 15 retroreflector array at Hadley Rille. Laser guide-star adaptive optics were used to compensate turbulence-induced aberrations across the transmitter's 1.5-m aperture. A 3.5-m telescope, also located at the SOR, was used as a receiver for detecting the return signals. JPL-supplied Chebyshev polynomials of the retroreflector locations were used to develop tracking algorithms for the telescopes. At times we observed in excess of 100 photons returned from a single pulse when the outgoing beam from the 1.5-m telescope was corrected by the adaptive optics system. No returns were detected when the outgoing beam was uncompensated. The experiment was conducted from March through September 1994, during the first or last quarter of the Moon.

Wilson, K. E.; Leatherman, P. R.; Cleis, R.; Spinhirne, J.; Fugate, R. Q.

1997-01-01

129

Entry vehicle performance analysis and atmospheric guidance algorithm for precision landing on Mars. M.S. Thesis - Massachusetts Inst. of Technology  

NASA Technical Reports Server (NTRS)

Future missions to Mars may require pin-point landing precision, possibly on the order of tens of meters. The ability to reach a target while meeting a dynamic pressure constraint to ensure safe parachute deployment is complicated at Mars by low atmospheric density, high atmospheric uncertainty, and the desire to employ only bank angle control. The vehicle aerodynamic performance requirements and guidance necessary for 0.5 to 1.5 lift drag ratio vehicle to maximize the achievable footprint while meeting the constraints are examined. A parametric study of the various factors related to entry vehicle performance in the Mars environment is undertaken to develop general vehicle aerodynamic design requirements. The combination of low lift drag ratio and low atmospheric density at Mars result in a large phugoid motion involving the dynamic pressure which complicates trajectory control. Vehicle ballistic coefficient is demonstrated to be the predominant characteristic affecting final dynamic pressure. Additionally, a speed brake is shown to be ineffective at reducing the final dynamic pressure. An adaptive precision entry atmospheric guidance scheme is presented. The guidance uses a numeric predictor-corrector algorithm to control downrange, an azimuth controller to govern crossrange, and analytic control law to reduce the final dynamic pressure. Guidance performance is tested against a variety of dispersions, and the results from selected tests are presented. Precision entry using bank angle control only is demonstrated to be feasible at Mars.

Dieriam, Todd A.

1990-01-01

130

Compensation of distributed delays in integrated communication and control systems  

NASA Technical Reports Server (NTRS)

The concept, analysis, implementation, and verification of a method for compensating delays that are distributed between the sensors, controller, and actuators within a control loop are discussed. With the objective of mitigating the detrimental effects of these network induced delays, a predictor-controller algorithm was formulated and analyzed. Robustness of the delay compensation algorithm was investigated relative to parametric uncertainties in plant modeling. The delay compensator was experimentally verified on an IEEE 802.4 network testbed for velocity control of a DC servomotor.

Ray, Asok; Luck, Rogelio

1991-01-01

131

A software method for color compensation.  

PubMed

When two or more fluorochromes are measured simultaneously, every detector sees some fluorescence from every fluorochrome. Spectral compensation is the process of removing the undesired overlap of signal. Although very successful for two and three fluorochromes, the general practice of adjusting instrument compensation becomes increasingly inadequate and unforgiving as the number of fluorochromes increases. When data are collected uncompensated, software compensation provides the flexibility of setting correct compensation every time for every sample. Software methods do have problems. The linearization assumptions made by the software algorithms may be more or less in error. Binning effects become more of a problem with increasing numbers of compensated parameters. This explanatory unit also contains protocols that illustrate the process of software compensation utilizing matrix algebra that provides for elements of all possible PMT detection combinations. Although details are limited to four colors, the principles described can be applied to any desired number. When two or more fluorochromes are measured simultaneously, every detector sees some fluorescence from every fluorochrome. PMID:18770774

Stewart, Carleton C; Stewart, Sigrid J

2003-02-01

132

Realtime motion compensation for ROV-based tele-operated underwater manipulators  

Microsoft Academic Search

This paper presents a novel underwater movement compensation algorithm for stabilization of manipulator position utilizing not ROV movements for disturbance compensation, but overlaid manipulator movements. A model based estimator is used to predict vehicle movement and provide the manipulation system with the necessary time to compensate for the estimated motion. It describes the conceptual benefits of this approach compared with

Marc Hildebrandt; Leif Christensen; Jochen Kerdels; Jan Albiez; Frank Kirchner

2009-01-01

133

Gmti Motion Compensation  

DOEpatents

Movement of a GMTI radar during a coherent processing interval over which a set of radar pulses are processed may cause defocusing of a range-Doppler map in the video signal. This problem may be compensated by varying waveform or sampling parameters of each pulse to compensate for distortions caused by variations in viewing angles from the radar to the target.

Doerry, Armin W. (Albuquerque, NM)

2004-07-20

134

The "dual-spot" Aethalometer: an improved measurement of aerosol black carbon with real-time loading compensation  

NASA Astrophysics Data System (ADS)

Aerosol black carbon is a unique primary tracer for combustion emissions. It affects the optical properties of the atmosphere and is recognized as the second most important anthropogenic forcing agent for climate change. It is the primary tracer for adverse health effects caused by air pollution. For the accurate determination of mass equivalent black carbon concentrations in the air and for source apportionment of the concentrations, optical measurements by filter-based absorption photometers must take into account the "filter loading effect". We present a new real-time loading effect compensation algorithm based on a two parallel spot measurement of optical absorption. This algorithm has been incorporated into the new Aethalometer model AE33. Intercomparison studies show excellent reproducibility of the AE33 measurements and very good agreement with post-processed data obtained using earlier Aethalometer models, and other filter-based absorption photometers. The real-time loading effect compensation algorithm provides the high-quality data necessary for real-time source apportionment, and for determination of the temporal variation of the compensation parameter k.

Drinovec, L.; Mo?nik, G.; Zotter, P.; Prvt, A. S. H.; Ruckstuhl, C.; Coz, E.; Rupakheti, M.; Sciare, J.; Mller, T.; Wiedensohler, A.; Hansen, A. D. A.

2014-09-01

135

Unbalance vibratory displacement compensation for active magnetic bearings  

NASA Astrophysics Data System (ADS)

As the dynamic stiffness of radial magnetic bearings is not big enough, when the rotor spins at high speed, unbalance displacement vibration phenomenon will be produced. The most effective way for reducing the displacement vibration is to enhance the radial magnetic bearing stiffness through increasing the control currents, but the suitable control currents are not easy to be provided, especially, to be provided in real time. To implement real time unbalance displacement vibration compensation, through analyzing active magnetic bearings (AMB) mathematical model, the existence of radial displacement runout is demonstrated. To restrain the runout, a new control scheme-adaptive iterative learning control (AILC) is proposed in view of rotor frequency periodic uncertainties during the startup process. The previous error signal is added into AILC learning law to enhance the convergence speed, and an impacting factor ? influenced by the rotor rotating frequency is introduced as learning output coefficient to improve the rotor control effects. As a feed-forward compensation controller, AILC can provide one unknown and perfect compensatory signal to make the rotor rotate around its geometric axis through power amplifier and radial magnetic bearings. To improve AMB closed-loop control system robust stability, one kind of incomplete differential PID feedback controller is adopted. The correctness of the AILC algorithm is validated by the simulation of AMB mathematical model adding AILC compensation algorithm through MATLAB soft. And the compensation for fixed rotational frequency is implemented in the actual AMB system. The simulation and experiment results show that the compensation scheme based on AILC algorithm as feed-forward compensation and PID algorithm as close-loop control can realize AMB system displacement minimum compensation at one fixed frequency, and improve the stability of the control system. The proposed research provides a new adaptive iterative learning control algorithm and control strategy for AMB displacement minimum compensation, and provides some references for time-varied displacement minimum compensation.

Gao, Hui; Xu, Longxiang; Zhu, Yili

2013-01-01

136

Coherent beam combining of two W-level fiber amplifiers in turbulence atmospheric environment based on stochastic parallel gradient descent algorithm  

NASA Astrophysics Data System (ADS)

We demonstrate coherent beam combining of two W-level fiber amplifiers based on stochastic parallel gradient descent (SPGD) algorithm at 8 m distance in a simulated turbulence atmospheric environment. A photodetector was used to get the coherent optical intensity of the main-lobe from a pinhole, based on the intensity and the SPGD algorithm, the phase controlling was performed by the digital signal processor. In order to simulate the atmospheric environment, turbulence was induced in the free space of the light path by fans and air-conditions in the lab. Experimental result shows that the system performs well for long-time both with and without the simulating turbulence in close-loop, combining efficiency as high as 84.25% with turbulence and 84.85% without turbulence were realized. Visibility increased from near zero in open-loop to 0.432 with turbulence and 0.505 without turbulence in close-loop and the residual phase error is controlled to be less than ?/18. The probability of energy encircled in the main-lobe to be more than 70% of its ideal value was increased from 18.66 to 93.71% without turbulence and from 14.80 to 92.49% with turbulence when the system evolves from open-loop to close-loop.

Wang, X. L.; Ma, Y. X.; Zhou, P.; Ma, H. T.; Li, X.; Xu, X. X.; Liu, Z. J.

2009-05-01

137

Measurement of Small Values of Hydrostatic Pressure with the Compensation of Atmospheric Pressure Influence / Pomiar Ma?ych Warto?ci Ci?nienia Hydrostatycznego Z Kompensacj? Wp?ywu Ci?nienia Atmosferycznego  

NASA Astrophysics Data System (ADS)

Knowledge of pressure distribution (or differential pressure ) determines the fluid flow description through the porous medium. In the case of big Reynolds numbers it is not difficult, but for laminar flows (i.e. for Re numbers Bear, 1988; Duckworth, 1983; Troskola?ski, 1957) from the scope 0.01 to 3) this description is virtually impossible on the basis of the tools available on the market. The previous study (Broda & Filipek, 2012) focused on the difficulty of measurement in the case of small differences of pressure and suggested a new original method for the measurement. A new unit for the measurement was constructed consisting of two separate measurement containers. Then the measurements were conducted, which necessitated temperature stabilization of the device and compensation of the atmospheric pressure influence on the measurement process. This paper presents the results of the continuation of research concerning the methods and equipment for the measurement of very small pressure differences. The paper includes also the experience gained from the new measurement unit, which was presented in figures 1-5 subsequently presenting the concept of measurement of small values of hydrodynamic pressure with compensation of atmospheric pressure influence fig. 1; illustration presenting the state corresponding to the case of the lack of flow through the tested item fig 2; state corresponding to the fluid flow through the tested item fig. 3; then the description of the measurement of pressure drop on the tested item fig. 4 and the measurement methodology (relations (1) - (20)). Picture of the measurement unit and its components - fig. 5. Furthermore, the authors present an exemplary measurement series and focus on the method of measurement and data processing - tables 1-8 and figures 6-8. Table 4 presents the comparison of the measurement unit used in the previous research (Broda & Filipek, 2012) and the new one - presented in the paper. It should be noted that the structure has been simplified and the measurement accuracy has increased. Znajomo?? rozk?adu ci?nienia (lub r?nicy ci?nie?) determinuje opis przep?ywu p?ynu przez o?rodek porowaty. W przypadku du?ych liczb Reynoldsa nie nastr?cza to wi?kszych trudno?ci, lecz dla przep?yww laminarnych (tj. dla liczb Re (Bear, 1988; Duckworth, 1983; Troskola?ski, 1957) z zakresu 0.01 do 3) jest to praktycznie niemo?liwe w oparciu o dost?pne na rynku przyrz?dy. Przyczyny powoduj?ce tak? sytuacj? zosta?y omwione w poprzednim opracowaniu (Broda i Filipek, 2012), w ktrym zwrcono uwag? na trudno?ci pomiarw zwi?zane z napi?ciem powierzchniowym czy w?oskowato?ci? (Adamson, 1997). Zaproponowano (Broda i Filipek, 2012) now?, autorsk? metod? pomiaru bardzo ma?ych r?nic ci?nie? oraz skonstruowano odpowiednie stanowisko sk?adaj?ce si? z dwch oddzielnych zbiornikw pomiarowych oraz przeprowadzono pomiary. Z przeprowadzonych bada? (Broda i Filipek, 2012) wynika?a konieczno?? zastosowania stabilizacji temperatury urz?dzenia oraz kompensacji wp?ywu ci?nienia atmosferycznego na proces pomiarowy. Niniejsza publikacja przedstawia wyniki kontynuacji bada? nad metodami i aparatur? do pomiaru bardzo ma?ych r?nic ci?nie? z uwzgl?dnieniem zdobytych do?wiadcze?, w oparciu o nowe stanowisko pomiarowe, ktrego zasad? dzia?ania i budow? przedstawiono na rys. 1-5, kolejno przedstawiaj?c koncepcj? wykonania pomiaru ma?ych warto?ci ci?nienia hydrodynamicznego z kompensacj? wp?ywu ci?nienia atmosferycznego rys. 1; ilustracj? obrazuj?c? stan odpowiadaj?cy przypadkowi braku przep?ywu p?ynu przez badany obiekt rys. 2; omawiaj?c stan odpowiadaj?cy przypadkowi przep?ywu p?ynu przez badany obiekt rys. 3. Kolejno omwiono stan odpowiadaj?cy pomiarowi spadku ci?nienia na badanym obiekcie rys. 4 oraz przedstawiono metodyk? pomiaru (zale?no?ci (1) - (20)). Zdj?cie stanowiska badawczego oraz jego elementw ilustruje rys. 5. W dalszej cz??ci artyku?u autorzy przedstawiaj? przyk?adow? seri? pomiarow? zwracaj

Broda, Krzysztof; Filipek, Wiktor

2013-09-01

138

The Algorithm Theoretical Basis Document for the Atmospheric Delay Correction to GLAS Laser Altimeter Ranges. Volume 8  

NASA Technical Reports Server (NTRS)

NASA s Ice, Cloud, and Land Elevation Satellite (ICESat) mission will be launched late 2001. It s primary instrument is the Geoscience Laser Altimeter System (GLAS) instrument. The main purpose of this instrument is to measure elevation changes of the Greenland and Antarctic icesheets. To accurately measure the ranges it is necessary to correct for the atmospheric delay of the laser pulses. The atmospheric delay depends on the integral of the refractive index along the path that the laser pulse travels through the atmosphere. The refractive index of air at optical wavelengths is a function of density and molecular composition. For ray paths near zenith and closed form equations for the refractivity, the atmospheric delay can be shown to be directly related to surface pressure and total column precipitable water vapor. For ray paths off zenith a mapping function relates the delay to the zenith delay. The closed form equations for refractivity recommended by the International Union of Geodesy and Geophysics (IUGG) are optimized for ground based geodesy techniques and in the next section we will consider whether these equations are suitable for satellite laser altimetry.

Herring, Thomas A.; Quinn, Katherine J.

2012-01-01

139

Reactive Power Compensator.  

DOEpatents

A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation. 26 figs.

El-Sharkawi, M.A.; Venkata, S.S.; Chen, M.; Andexler, G.; Huang, T.

1992-07-28

140

Reactive power compensator  

DOEpatents

A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation.

El-Sharkawi, Mohamed A. (Renton, WA); Venkata, Subrahmanyam S. (Woodinville, WA); Chen, Mingliang (Kirkland, WA); Andexler, George (Everett, WA); Huang, Tony (Seattle, WA)

1992-01-01

141

Feed-forward Compensation of load and parameter variations of electric drive  

Microsoft Academic Search

The paper presents a method to compensate effects caused by slow varying loads and plant parameters drift as well as by detuned controller using a simple yet robust algorithm in voltage controlled electric drives. In case of known variations an analytical expression of pre-computed feed-forward compensation voltage is derived, while in presence of unknown disturbances the control algorithm uses a

Alon Kuperman; Yoram Horen; Saad Tapuchi; Uri Suissa

2008-01-01

142

Nonlinear compensation technologies for future optical communication systems  

NASA Astrophysics Data System (ADS)

Digital nonlinear compensation techniques have been thought to be keys to realize further spectrally efficient optical fiber communication systems. The most critical issue of the digital nonlinear compensation algorithms has been their computational complexity, or gate count of digital signal processing circuit. Among several approaches, digital nonlinear compensation algorithms based on perturbation analysis are attractive in terms of the hardware efficiency because the algorithms can compensate the accumulated nonlinear noise over all transmission spans with only one stage. In this paper, we discuss three approaches to sophisticate the perturbation nonlinear compensation. First, we illustrate a perturbation-based post-equalization method to improve the robustness to transceiver device imperfections. We next propose and numerically evaluate a symbol degeneration method to extend the perturbation nonlinear compensation methods to higher-order QAM without increasing the computational complexity. Finally, we discuss a sub-band processing of perturbation nonlinear compensation for further computational complexity reduction. By combining the perturbation method with Nyquist frequency division multiplexing, the computational complexity of perturbation calculation is reduced by a factor of more than 10 for 3000-km single-channel transmission of 128 Gbit/s dualpolarization QPSK with only 0.1 dB performance degradation.

Oyama, Tomofumi; Hoshida, Takeshi; Nakashima, Hisao; Oda, Shoichiro; Yamauchi, Tomohiro; Tanimura, Takahito; Dou, Liang; Zhao, Ying; Tao, Zhenning; Rasmussen, Jens C.

2015-01-01

143

An algorithm for retrieval of ocean surface and atmospheric parameters from the observations of the scanning multichannel microwave radiometer  

Microsoft Academic Search

The scanning multichannel microwave radiometer is a five-frequency (6.6, 10.7, 18, 21, and 37 GHz), dual-polarized microwave radiometer, which was launched in two separate satellites, Nimbus 7 and Seasat, in 1978. A formalism is developed which can be used to interpret the data in terms of sea surface temperature, sea surface wind speed, and the atmospheric content of water vapor

T. T. Wilheit; A. T. C. Chang

1980-01-01

144

Validation of CFC12 measurements from the Improved Limb Atmospheric Spectrometer (ILAS) with the version 6.0 retrieval algorithm  

Microsoft Academic Search

Measurements of CFC-12 were made by the Improved Limb Atmospheric Spectrometer (ILAS) between 57N and 72N in the Northern Hemisphere and between 64S and 89S in the Southern Hemisphere. ILAS was launched on 17 August 1996 on board the Advanced Earth Observing Satellite (ADEOS). The ILAS validation balloon campaigns were carried out from Kiruna, Sweden (68N, 21E), in February and

F. Khosrawi; R. Mller; H. Irie; A. Engel; G. C. Toon; B. Sen; S. Aoki; T. Nakazawa; W. A. Traub; K. W. Jucks; D. G. Johnson; H. Oelhaf; G. Wetzel; T. Sugita; H. Kanzawa; T. Yokota; H. Nakajima; Y. Sasano

2004-01-01

145

Workers' Compensation and Teacher Stress.  

ERIC Educational Resources Information Center

Examines the Workers' Compensation system and teacher stress to determine if a burned-out teacher should be eligible for Workers' Compensation benefits. Concludes that although most states do not allow Workers' Compensation benefits to burned-out teachers, compensation should be granted because the injuries are real and work-related. (Contains 48

Nisbet, Michael K.

1999-01-01

146

Evaluating a mesoscale atmosphere model and a satellite-based algorithm in estimating extreme rainfall events in northwestern Turkey  

NASA Astrophysics Data System (ADS)

Quantitative precipitation estimates are obtained with more uncertainty under the influence of changing climate variability and complex topography from numerical weather prediction (NWP) models. On the other hand, hydrologic model simulations depend heavily on the availability of reliable precipitation estimates. Difficulties in estimating precipitation impose an important limitation on the possibility and reliability of hydrologic forecasting and early warning systems. This study examines the performance of the Weather Research and Forecasting (WRF) model and the Multi Precipitation Estimates (MPE) algorithm in producing the temporal and spatial characteristics of the number of extreme precipitation events observed in the western Black Sea region of Turkey. Precipitation derived from WRF model with and without the three-dimensional variational (3DVAR) data assimilation scheme and MPE algorithm at high spatial resolution (5 km) are compared with gauge precipitation. WRF-derived precipitation showed capabilities in capturing the timing of precipitation extremes and to some extent the spatial distribution and magnitude of the heavy rainfall events, whereas MPE showed relatively weak skills in these aspects. WRF skills in estimating such precipitation characteristics are enhanced with the application of the 3DVAR scheme. Direct impact of data assimilation on WRF precipitation reached up to 12% and at some points there is a quantitative match for heavy rainfall events, which are critical for hydrological forecasts.

Yucel, I.; Onen, A.

2014-03-01

147

An improvement to the volcano-scan algorithm for atmospheric correction of CRISM and OMEGA spectral data  

E-print Network

The observations of Mars by the CRISM and OMEGA hyperspectral imaging spectrometers require correction for photometric, atmospheric and thermal effects prior to the interpretation of possible mineralogical features in the spectra. Here, we report on a simple, yet non-trivial, adaptation to the commonly-used volcano-scan correction technique for atmospheric CO_2, which allows for the improved detection of minerals with intrinsic absorption bands at wavelengths between 1.9-2.1 $\\mu$m. This volcano-scan technique removes the absorption bands of CO_2 by ensuring that the Lambert albedo is the same at two wavelengths: 1.890 $\\mu$m and 2.011 $\\mu$m, with the first wavelength outside the CO_2 gas bands and the second wavelength deep inside the CO_2 gas bands. Our adaptation to the volcano-scan technique moves the first wavelength from 1.890 $\\mu$m to be instead within the gas bands at 1.980 $\\mu$m, and for CRISM data, our adaptation shifts the second wavelength slightly, to 2.007 $\\mu$m. We also report on our effort...

McGuire, Patrick C; Brown, Adrian J; Fraeman, Abigail A; Marzo, Giuseppe A; Morgan, M Frank; Murchie, Scott L; Mustard, John F; Parente, Mario; Pelkey, Shannon M; Roush, Ted L; Seelos, Frank P; Smith, Michael D; Wendt, Lorenz; Wolff, Michael J

2009-01-01

148

An advanced optimal spectral estimation algorithm in fourier spectroscopy with application to remote sensing of the atmosphere  

SciTech Connect

Remote sensing of the atmosphere from satellite to improve numerical weather prediction demands objective data handling methods, as the effectiveness of satellite data ultimately rests on our ability to process the data in real time. In this paper a procedure to recover high-resolution spectra from infrared Fourier spectrometer data is presented. The technique relies on the generalized cross-validation criterion and retains all the computational characteristics that are proper to the fast Fourier transform. The procedure yields adaptive apodizing functions that improve the convergence of the Fourier transform. Numerical examples are carried out using synthetic spectra computed by a high-resolution radiative transfer code. The effect of additive noise is also analyzed. The application of the technique to remote sensing of the atmosphere is discussed. Although our applications of the method emphasize the problem of recovering radiance spectra from interferogram signals, the procedure also applied in a general context, for example, to the estimation of variance spectra of stochastic processes from their autocovariance functions. 14 refs., 5 figs., 4 tabs.

Amato, U. [Instituto per Applicazioni della Matematica CNR, Napoli (Italy)] [Instituto per Applicazioni della Matematica CNR, Napoli (Italy); Cuomo, V.; Serio, C. [Universita della Basilicata, Potenza (Italy)] [Universita della Basilicata, Potenza (Italy)

1993-09-01

149

Clouds and the Earth's Radiant Energy System (CERES) Algorithm Theoretical Basis Document. Volume 3; Cloud Analyses and Determination of Improved Top of Atmosphere Fluxes (Subsystem 4)  

NASA Technical Reports Server (NTRS)

The theoretical bases for the Release 1 algorithms that will be used to process satellite data for investigation of the Clouds and Earth's Radiant Energy System (CERES) are described. The architecture for software implementation of the methodologies is outlined. Volume 3 details the advanced CERES methods for performing scene identification and inverting each CERES scanner radiance to a top-of-the-atmosphere (TOA) flux. CERES determines cloud fraction, height, phase, effective particle size, layering, and thickness from high-resolution, multispectral imager data. CERES derives cloud properties for each pixel of the Tropical Rainfall Measuring Mission (TRMM) visible and infrared scanner and the Earth Observing System (EOS) moderate-resolution imaging spectroradiometer. Cloud properties for each imager pixel are convolved with the CERES footprint point spread function to produce average cloud properties for each CERES scanner radiance. The mean cloud properties are used to determine an angular distribution model (ADM) to convert each CERES radiance to a TOA flux. The TOA fluxes are used in simple parameterization to derive surface radiative fluxes. This state-of-the-art cloud-radiation product will be used to substantially improve our understanding of the complex relationship between clouds and the radiation budget of the Earth-atmosphere system.

1995-01-01

150

Compensating For Unbalance In Pulse-Code Phase Modulation  

NASA Technical Reports Server (NTRS)

Algorithm proposed for use in pulse-code phase-modulation transmitter in which non-return-to-zero (NRZ) or biphase data modulated directly onto radio-frequency residual carrier signal. Devised to compensate somewhat for effect, upon distant receiver, of unbalance in stream of transmitted data. Formulated to compute combinations of modulation index, data rate, and transmitter power compensating for measured unbalance in transmitted data stream.

Nguyen, Tien M.; Hinedi, Sami M.

1995-01-01

151

Robust beam compensation for laser-based additive manufacturing  

Microsoft Academic Search

Todays software for laser-based additive manufacturing compensates for the finite dimensions of the laser spot by insetting the contours of a solid part. However, features having smaller dimensions are removed by this operation, which may significantly alter the structure of thin-walled parts. To avoid potential production errors, this work describes in detail an algorithmic framework that makes beam compensation more

Maarten Moesen; Tom Craeghs; Jean-Pierre Kruth; Jan Schrooten

2011-01-01

152

Accelerometer-based position reconstruction for the feedforward compensation of fast telescope vibrations in the E-ELT/MICADO  

NASA Astrophysics Data System (ADS)

The amount of image motion caused by vibrations of the telescope structure increases with the size of the telescope. Compensating the effects of structural vibrations in the optical path will be a major design question for adaptive optics (AO) systems in future extremely large telescopes like the E-ELT. A promising control system architecture is the recently developed Dual-Loop-Approach, with a feedforward loop based on accelerometer measurements, compensating for the vibrations in addition to the classical AO feedback loop compensating for atmospheric turbulences. We present our efforts to develop sophisticated estimation and control algorithms for this feedforward loop. The major task from a control engineering point of view is reconstructing the position of the vibrating elements from accelerometer measurements highly deteriorated by low-frequency drift and highfrequency noise. The algorithms are evaluated and compared using a realistic Tip-Tilt-Vibration laboratory test setup. Position reconstruction for a realistic 8 Hz structural resonance with an error of only 4% is achieved. Our ultimate goal is to achieve longer and more sensitive wavefront sensor (WFS) integrations by permitting a smaller bandwidth of the AO feedback loop in the E-ELT/MICADO.

Keck, Alexander; Pott, Jrg-Uwe; Sawodny, Oliver

2014-07-01

153

Use of the Advanced Canopy-Atmosphere-Soil Algorithm (ACASA) model to determine flux quality and gap-fill nighttime data at multiple AmeriFlux sites  

NASA Astrophysics Data System (ADS)

While gaps in trace-gas fluxes measured via eddy-covariance occur for a variety of reasons, many occur at night due to a stratified (stable) atmosphere close to the surface. Currently, the community standard for eliminating data during periods of stability is to apply a threshold of friction velocity (u*). Despite applying the u* threshold, data often indicate net CO2 uptake at night, casting doubt on whether a u* threshold is accurately eliminating data from stable periods. If, in fact, the u* correction does not eliminate data appropriately, this will influence net annual carbon budgets in two important ways. First, inaccurate nighttime respiration data may remain after post-processing and bias net annual sums toward a stronger sink of CO2. Secondly, if data gaps (created by imposing a u* threshold) are filled by applying empirically derived temperature-moisture response functions based on remaining data, the gap-filled or "corrected" data are then influenced by the possible inaccuracy of the respiration data taken under high u*. Because most flux sites are only equipped with one set of instruments (usually just above the canopy), vertical profiles of turbulent transfer within and above the canopy are generally not available providing few alternatives to the u* correction method to the greater FLUXNET community. The ability to better quantify atmospheric stability within and above the canopy would improve data quality assessment. We test this theory by modeling vertical profiles of turbulent kinetic energy (TKE) using the Advanced Canopy-Atmosphere-Soil Algorithm (ACASA) and comparing it to high frequency TKE data collected by deploying an upward-facing LiDAR (measurements up to 200m) at two AmeriFlux towers: Wind River in Washington and Tonzi in California. LiDar data were collected during a 2-week long spring campaign at each site as well as during a late-summer and fall campaign at Tonzi. Here we show the effect of assessing canopy stability (and thus flux quality) via thresholds based on u* (from eddy-covariance) versus vertical profiles of TKE (from ACASA and LiDAR). Additionally, we validate the model by comparing output to measurements of soil respiration (via the chamber method) and vertical profiles of temperature and wind velocity (via radiosonde measurements). Finally, we compare modeled nighttime fluxes of CO2 to measured fluxes of CO2 during periods when the atmosphere is well-mixed based on the new TKE threshold. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Osuna, J. L.; Wharton, S.; Falk, M.; Paw U, K.; Baldocchi, D. D.; Bible, K.

2012-12-01

154

Phase compensation on EPS  

Microsoft Academic Search

For the purpose of improving the performance of Electric Power Steering System (EPS), phase compensation must be added on the control strategies. Two methods, including speed feedback and differentiation, are discussed in this paper. As to the latter, the emphasis is made on the differences of ideal differentiation and actual one. Simulation results show that the above mentioned methods could

Xia Fugen; Ji Xuewu

2010-01-01

155

Reactive Power Compensating System.  

DOEpatents

The circuit was designed for the specific application of wind-driven induction generators. It has great potential for application in any situation where a varying reactive power load is present, such as with induction motors or generators, or for transmission network compensation.

Williams, Timothy J.; El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.

1985-01-04

156

On adaptive friction compensation  

Microsoft Academic Search

A method of compensating for friction in control systems is presented. The method entails the use of an observer to estimate the friction which is modeled as a constant times the sign of the velocity. The purpose of the observer is to estimate this constant. The observer model is selected to ensure that the error in estimation of the friction

Bernard Friedland; Young-Jin Park

1992-01-01

157

HR-Compensation Compensation Actions Checklist ePAF # Position #  

E-print Network

HR-Compensation Compensation Actions Checklist ePAF # Position # Below are the required documents by Compensation Action EstablishingaPosition FTEChange Liability/Home DepartmentChange OutofCycleMerit Increase occupied) Employment Application* (if occupied) Position Change ePAF (if vacant) Position

Wu, Shin-Tson

158

Executive Compensation, Incentives, and Risk  

E-print Network

This paper analyzes the link between equity-based compensation and created incentives by (1) deriving a measure of incentives suitable for both linear and non-linear compensation contracts, (2) analyzing the effect of risk ...

Jenter, Dirk

2004-05-28

159

Executive Compensation, Incentives, and Risk  

E-print Network

This paper analyzes the link between equity-based compensation and created incentives by (1) deriving a measure of incentives suitable for both linear and non-linear compensation contracts, (2) analyzing ...

Jenter, Dirk

2004-12-10

160

Deferred Compensation Becomes More Common  

ERIC Educational Resources Information Center

A key part of the compensation package for some college and university presidents is money that they do not receive in their paychecks. Formally known as deferred compensation, such payments can take many forms, including supplemental retirement pay, severance pay, or even bonuses. With large institutions leading the way, deferred compensation has

June, Audrey Williams

2006-01-01

161

Subsurface Xenon Migration by Atmospheric Pumping Using an Implicit Non-Iterative Algorithm for a Locally 1D Dual-Porosity Model  

NASA Astrophysics Data System (ADS)

An underground nuclear explosion injects radionuclids in the surrounding host rock creating an initial radionuclid distribution. In the case of fractured permeable media, cyclical changes in atmospheric pressure can draw gaseous species upwards to the surface, establishing a ratcheting pump effect. The resulting advective transport is orders of magnitude more significant than transport by molecular diffusion. In the 1990s the US Department of Energy funded the socalled Non-Proliferation Experiment conducted by the Lawrence Livermore National Laboratory to investigate this barometric pumping effect for verifying compliance with respect to the Comprehensive Nuclear Test Ban Treaty. A chemical explosive of approximately 1 kt TNT-equivalent has been detonated in a cavity located 390 m deep in the Rainier Mesa (Nevada Test Site) in which two tracer gases were emplaced. Within this experiment SF6 was first detected in soil gas samples taken near fault zones after 50 days and 3He after 325 days. For this paper a locally one-dimensional dual-porosity model for flow along the fracture and within the permeable matrix was used after Nilson and Lie (1990). Seepage of gases and diffusion of tracers between fracture and matrix are accounted. The advective flow along the fracture and within the matrix block is based on the FRAM filtering remedy and methodology of Chapman. The resulting system of equations is solved by an implicit non-iterative algorithm. Results on time of arrival and subsurface concentration levels for the CTBT-relevant xenons will be presented.

Annewandter, R.; Kalinowksi, M. B.

2009-04-01

162

Ground difference compensating system  

SciTech Connect

A method of ground level compensation includes measuring a voltage of at least one signal with respect to a primary ground potential and measuring, with respect to the primary ground potential, a voltage level associated with a secondary ground potential. A difference between the voltage level associated with the secondary ground potential and an expected value is calculated. The measured voltage of the at least one signal is adjusted by an amount corresponding to the calculated difference.

Johnson, Kris W.; Akasam, Sivaprasad

2005-10-25

163

Improved satellite attitude control using a disturbance compensator  

NASA Astrophysics Data System (ADS)

An attitude control algorithm using a disturbance compensator has been developed for three-axis-controlled satellites with flexible appendages. It consists of a compensator to stabilize the system (e.g., PD control), a filter to prevent excitation of the neglected higher flexible-mode vibration (e.g., a low-pass filter), and a compensator to suppress the effect of disturbances on the satellite attitude. This disturbance compensator can be designed in the frequency-domain in terms of the robust model matching design method, and also, in the time-domain in terms of the observer/estimator approach. The designed compensator can easily be implemented for a conventional attitude control system. Theoretically, the disturbance compensator makes it possible to assure arbitrarily low sensitivity over any frequency range for disturbances due not only to the environment but also to structural flexibility with keeping the control performance for reference inputs. Thus, the control algorithm can improve the control performance of satellites with the flexible structures. It is applied for the attitude control system of the Japanese VLBI satellite, "HALCA", launched on February 12, 1997.

Yamashita, Toshiaki; Ogura, Naoto; Kurii, Toshihiro; Hashimoto, Tatsuaki

2004-07-01

164

Irradiance compensation control for high-energy laser propagation  

SciTech Connect

The quality of propagated Laser light strongly depends on the degree of phase uniformity across the beam at its source. When propagating through turbulent atmosphere, a Strehl ratio of nearly 0.9 is possible if phase correction is made at all spatial scales greater than approximately r{sub o}, the Fried atmospheric cell size. Therefore r{sub o} is a reasonable choice for actuator spacing on the phase compensating adaptive optics. However, analysis of high energy laser propagation has shown that a control law designed to compensate only for atomspheric index fluctuations will drive thermal blooming instabilities. Small initial perturbations in beam irradiance will grow exponentially until the beam breaks up. Therefore it is necessary also to compensate for irradiance perturbations at the same spatial scale as the compensation for phase. Combined phase and irradiance compensation of an HEL has been shown to be stable in theory. Irradiance control can be accomplished with a pair of deformable mirrors spaced apart over a propagation path. Laser light reflected off of the first deformable mirror surface at z = 0 will result in magnitude perturbations some distance away at z = L. The second deformable mirror then recollimates the light. The purpose of simulating the irradiance compensation system is to test the baseline design in such a way that the effect of discrete actuator/sensors and beam edge effects is taken into account in a more realistic manner than can be performed by a 2-D fourier analysis. 7 refs., 9 figs.

Gavel, D.T.

1991-04-18

165

An efficient error compensation system for CNC multi-axis machines  

Microsoft Academic Search

To enhance a machines ability for a precision machining task, an efficient compensation scheme that takes all error sources into account is needed. In this study, an effective static\\/quasi-static error compensation system composed of an interpolation algorithm based on shape functions for error prediction, and a recursive software compensation procedure, was developed. The new error prediction scheme is efficient enough

Shih-Ming Wang; Yuan-Liang Liu; Yuan Kang

2002-01-01

166

Reticle specific compensations to meet production overlay requirements for 64 MB and beyond  

NASA Astrophysics Data System (ADS)

A novel technology has been developed whereby a database of reticle specific compensation can be utilized to correct for magnification, rotation, and translational reticle manufacturing errors. Whenever a given reticle is loaded into the stepper, a reticle barcode defining that specific reticle is read. This barcode is associated with a set of reticle specific compensations that are automatically applied during the execution of a production batch. Reticle compensations can be either empirically determined or taken from reticle manufacturing information. Algorithms have been developed which determine reticle specific compensations based on either the manufacturing data or empirically determined data. This data is easily entered into a database allowing any stepper to access reticle compensation information for any reticle. This paper discusses the procedures involved in determining and implementing reticle specific compensations and presents production overlay data indicating overlay performance with and without reticle compensations.

Rogoff, Richard; Hong, Syi-Sying; Schramm, Doug; Espin, Gregg D.

1994-05-01

167

Springback Prediction, Compensation and Correlation for Automotive Stamping  

SciTech Connect

To reduce weight and increase fuel efficiency and safety, more and more automotive sheet stamping parts are being made of aluminum and high strength steels. Forming of such materials encounters not just reduced formability but also dimensional quality problems. Springback prediction accuracy and compensation effectiveness have been the major challenge to die development, construction and tryout. In this paper, the factors that affect the accuracy of springback prediction are discussed, which includes the effect of material models, the selection of element size, and the contact algorithms. Springback predictions of several automotive aluminum and high strength panels are compared with measurement data. The examples show that the prediction correlates with measurement data in both springback trend and magnitude. The effect of springback on final product can be reduced or eliminated through process control and die face compensation. The process control method involves finding the root causes of springback and eliminating them through process modification. The geometrical compensation of die surface is a direct way to eliminate the springback effect. The global scaling compensation method is normally limited to parts with relatively small springback. For large springback and twisting, a new approach is discussed, which takes into account of the effect of deformation and springback history. The compensation is achieved iteratively by solving a system of non-linear equations. Production dies were cut to the compensated surface, which shows that the die compensation is an efficient way to reduce springback-induced geometry deviation.

Xu Siguang; Zhao Kunmin; Lanker, Terry; Zhang, Jimmy; Wang, C.T. [General Motors Corp., Manufacturing Engineering, Die Center, 2000 Centerpoint, Pontiac, MI 48341 (United States)

2005-08-05

168

Regulation with on-line gravity compensation for robots with elastic joints  

E-print Network

to static friction and/or uncertainty in the gravity compensation. I. INTRODUCTION Control algorithmsRegulation with on-line gravity compensation for robots with elastic joints Loredana Zollo Scuola,80125 Napoli, Italy Email: siciliano@unina.it Abstract--In this paper a PD control with on-line gravity

De Luca, Alessandro

169

COMPENSATING THE TRANSMISSION DELAY IN NETWORKED CONTROL SYSTEMS N., Georgesb  

E-print Network

COMPENSATING THE TRANSMISSION DELAY IN NETWORKED CONTROL SYSTEMS Vatanskia N., Georgesb J.-P., Aubrunb C., Rondeaub E. and S.-L. Jms-Jounelaa a) Research Centre for Automatic Control (CRAN UMR 7039 transmission in the switched Ethernet network is presented. The upper bound delay algorithm applies ideas from

Paris-Sud XI, Universit de

170

COMPENSATING SMALL HEAD DISPLACEMENTS FOR AN ACCURATE FMRI REGISTRATION  

E-print Network

COMPENSATING SMALL HEAD DISPLACEMENTS FOR AN ACCURATE FMRI REGISTRATION Diane Lingrand, Johan in a MRI scanner. This algorithm has been successfully tested on 6 sets of fMRI volumes acquired at the MNI (regions of activity in fMRI sequences, modifica- tions in lesions in MRI sequences, ...). fMRIh fMRIh f

Boyer, Edmond

171

Second Order Motion Compensation for Squinted Spotlight Synthetic Aperture Radar  

E-print Network

Second Order Motion Compensation for Squinted Spotlight Synthetic Aperture Radar Minh Phuong Nguyen motion com- pensation (MoCom) algorithm for squinted spotlight synthetic aperture radar (SAR). A preciseRCMC will be inverted to retain the range compressed SAR data for the subsequent Omega-K processing. This paper

172

Self-compensating tensiometer and method  

DOEpatents

A pressure self-compensating tensiometer and method to in situ determine below grade soil moisture potential of earthen soil independent of changes in the volume of water contained within the tensiometer chamber, comprising a body having first and second ends, a porous material defining the first body end, a liquid within the body, a transducer housing submerged in the liquid such that a transducer sensor within the housing is kept below the working fluid level in the tensiometer and in fluid contact with the liquid and the ambient atmosphere.

Hubbell, Joel M. (Idaho Falls, ID); Sisson, James B. (Idaho Falls, ID)

2003-01-01

173

Bobcat 2013: a hyperspectral data collection supporting the development and evaluation of spatial-spectral algorithms  

NASA Astrophysics Data System (ADS)

The amount of hyperspectral imagery (HSI) data currently available is relatively small compared to other imaging modalities, and what is suitable for developing, testing, and evaluating spatial-spectral algorithms is virtually nonexistent. In this work, a significant amount of coincident airborne hyperspectral and high spatial resolution panchromatic imagery that supports the advancement of spatial-spectral feature extraction algorithms was collected to address this need. The imagery was collected in April 2013 for Ohio University by the Civil Air Patrol, with their Airborne Real-time Cueing Hyperspectral Enhanced Reconnaissance (ARCHER) sensor. The target materials, shapes, and movements throughout the collection area were chosen such that evaluation of change detection algorithms, atmospheric compensation techniques, image fusion methods, and material detection and identification algorithms is possible. This paper describes the collection plan, data acquisition, and initial analysis of the collected imagery.

Kaufman, Jason; Celenk, Mehmet; White, A. K.; Stocker, Alan D.

2014-06-01

174

An Examination Of Altitude Compensation Through Idealised Nozzles and Trajectories  

NASA Astrophysics Data System (ADS)

This paper presents an analysis of the impact of applying altitude compensating nozzles to two representative vehicles. The first is the Space Shuttle, typical of modern high performance systems that operate a single propulsive unit from sea level to vacuum, and the second is Reaction Engines Limited Skylon spaceplane, representative of advanced single stage to orbit concepts. A general investigation of advanced nozzle concepts is provided by one dimensional analysis, using ideal and non- ideal compensating, and non-compensating nozzles. The effect of imperfect compensation (resulting in lower effective exit pressures than ambient) on altitude compensating nozzles is analysed, as is the removal of the restriction on maximum area ratio, made possible by these devices. A simplified trajectory analysis is used to reduce the complexity of the process and maintain generality. Although the use of a fixed trajectory for all nozzles means that some fidelity to the real world is lost, particularly as the area ratio or compensation efficiency is increased, the results qualitatively demonstrate that the impact of compensation efficiency is relatively small compared to that of the removal of the limitation on area ratio. This is particularly true for Shuttle type trajectories, where the vehicle leaves the atmosphere as rapidly as possible. The increase in payload estimated by the current analysis is significant, in some cases being over 25%. Although practical considerations not included mean that the increase in payload realistically feasible will not be as large as this, even a relatively small fraction of this value still represents an attractive proposition, and demonstrates that compensating nozzles provide a promising route to lowering launch costs per kilogramme. This is particularly the case if, as is implied by these results, the actual compensating pressure is not particularly important.

Taylor, N.

175

Laser Gyro Temperature Compensation Using Modified RBFNN  

PubMed Central

To overcome the effect of temperature on laser gyro zero bias and to stabilize the laser gyro output, this study proposes a modified radial basis function neural network (RBFNN) based on a Kohonen network and an orthogonal least squares (OLS) algorithm. The modified method, which combines the pattern classification capability of the Kohonen network and the optimal choice capacity of OLS, avoids the random selection of RBFNN centers and improves the compensation accuracy of the RBFNN. It can quickly and accurately identify the effect of temperature on laser gyro zero bias. A number of comparable identification and compensation tests on a variety of temperature-changing situations are completed using the multiple linear regression (MLR), RBFNN and modified RBFNN methods. The test results based on several sets of gyro output in constant and changing temperature conditions demonstrate that the proposed method is able to overcome the effect of randomly selected RBFNN centers. The running time of the method is about 60 s shorter than that of traditional RBFNN under the same test conditions, which suggests that the calculations are reduced. Meanwhile, the compensated gyro output accuracy using the modified method is about 7.0 10?4 /h; comparatively, the traditional RBFNN is about 9.0 10?4 /h and the MLR is about 1.4 10?3 /h. PMID:25302814

Ding, Jicheng; Zhang, Jian; Huang, Weiquan; Chen, Shuai

2014-01-01

176

Compensation Performance for Induction Motor Load of Voltage Dip Compensator  

NASA Astrophysics Data System (ADS)

The variable speed drives of the power electronics application are the most sensitive to the voltage dip that is caused by power system fault. Variable speed drives are composed by the converter, the voltage source inverter and induction motor. They could fall into operation failure by wrong control in the converter when degree of the voltage dip exceeds 15% and 10ms. Therefore, important loads are equipped with the voltage dip compensation. Since the load characteristic of the converter equals nearly the impedance load, the induction motors connected directly to power supply are more sensitive to the output voltage waveform of the compensator than the converter. Thus, the induction motors are used as the important load (compensated load) on the simulation. The simulations of the compensation performance to the induction motors are carried out by using simulation tool PSCAD/EMTDC. It is confirmed that the goal of the compensation performance is able to be achieved.

Nagamoto, Takamichi; Takayama, Katsumi; Kai, Takaaki

177

Compensations during Unsteady Locomotion.  

PubMed

Locomotion in a complex environment is often not steady, but the mechanisms used by animals to power and control unsteady locomotion (stability and maneuverability) are not well understood. We use behavioral, morphological, and impulsive perturbations to determine the compensations used during unsteady locomotion. At the level both of the whole-body and of joints, quasi-stiffness models are useful for describing adjustments to the functioning of legs and joints during maneuvers. However, alterations to the mechanics of legs and joints often are distinct for different phases of the step cycle or for specific joints. For example, negotiating steps involves independent changes of leg stiffness during compression and thrust phases of stance. Unsteady locomotion also involves parameters that are not part of the simplest reduced-parameter models of locomotion (e.g., the spring-loaded inverted pendulum) such as moments of the hip joint. Extensive coupling among translational and rotational parameters must be taken into account to stabilize locomotion or maneuver. For example, maneuvers with morphological perturbations (increased rotational inertial turns) involve changes to several aspects of movement, including the initial conditions of rotation and ground-reaction forces. Coupled changes to several parameters may be employed to control maneuvers on a trial-by-trial basis. Compensating for increased rotational inertia of the body during turns is facilitated by the opposing effects of several mechanical and behavioral parameters. However, the specific rules used by animals to control translation and rotation of the body to maintain stability or maneuver have not been fully characterized. We initiated direct-perturbation experiments to investigate the strategies used by humans to maintain stability following center-of-mass (COM) perturbations. When walking, humans showed more resistance to medio-lateral perturbations (lower COM displacement). However, when running, humans could recover from the point of maximum COM displacement faster than when walking. Consequently, the total time necessary for recovery was not significantly different between walking and running. Future experiments will determine the mechanisms used for compensations during unsteady locomotion at the behavioral, joint, and muscle levels. Using reduced-parameter models will allow common experimental and analytical frameworks for the study of both stability and maneuverability and the determination of general control strategies for unsteady locomotion. PMID:24948138

Qiao, Mu; Jindrich, Devin L

2014-12-01

178

Coronary artery motion compensation in spiral CT  

NASA Astrophysics Data System (ADS)

Because of motion artifacts, spiral Computer Tomography (CT) is not presently a widely useful diagnostic tool in cardiac imaging. There are two time scales in CT data acquisition. The first is the time-scale of a single projection which is roughly a half millisecond. The second time-scale is that of a single rotation of the x-ray source which is about 400 ms. For diagnostic purposes, the fastest components of the heart cycle are on the order of 5 ms. Those of general interest are in the range of about 100 ms. Full-rotation CT acquisition is slower than required for freezing the cardiac motion of interest. This mismatch in speed causes motion artifacts in the reconstructed images. We focus our attention on accurately measuring lumen dimensions and on visualizing lesion architecture. This analysis requires local imaging; it does not require global motion compensation. The methods we use relate to one-dimensional motion tracking and motion compensation applied to the projection data. Dynamic programming is used for the tracking. Following the projection processing, the CT reconstruction algorithm then acts on the motion-corrected projection data to produce the reconstructed image. In addition to applying motion compensation to the projections, we also use region-of-interest (ROI) CT reconstruction algorithms in order to utilize the locally motion-corrected projection data without generating artifacts. Those artifacts come from missing projection data that should come from outside ROI. In our case the ROI is the cross-section of the vessel being imaged.

Dallas, William J.; Ovitt, Theron W.

2005-04-01

179

Temperature compensated photovoltaic array  

DOEpatents

A temperature compensated photovoltaic module (20) comprised of a series of solar cells (22) having a thermally activated switch (24) connected in parallel with several of the cells (22). The photovoltaic module (20) is adapted to charge conventional batteries having a temperature coefficient (TC) differing from the temperature coefficient (TC) of the module (20). The calibration temperatures of the switches (24) are chosen whereby the colder the ambient temperature for the module (20), the more switches that are on and form a closed circuit to short the associated solar cells (22). By shorting some of the solar cells (22) as the ambient temperature decreases, the battery being charged by the module (20) is not excessively overcharged at lower temperatures. PV module (20) is an integrated solution that is reliable and inexpensive.

Mosher, Dan Michael (Plano, TX)

1997-11-18

180

Temperature compensated photovoltaic array  

DOEpatents

A temperature compensated photovoltaic module comprises a series of solar cells having a thermally activated switch connected in parallel with several of the cells. The photovoltaic module is adapted to charge conventional batteries having a temperature coefficient differing from the temperature coefficient of the module. The calibration temperatures of the switches are chosen whereby the colder the ambient temperature for the module, the more switches that are on and form a closed circuit to short the associated solar cells. By shorting some of the solar cells as the ambient temperature decreases, the battery being charged by the module is not excessively overcharged at lower temperatures. PV module is an integrated solution that is reliable and inexpensive. 2 figs.

Mosher, D.M.

1997-11-18

181

Implementing Innovative Staff Compensation Strategies.  

ERIC Educational Resources Information Center

Discusses what the compensation manager at a diverse college or university can do with scant resources to meet the varied compensation needs of the institution. Offers as an example the University of Florida system, which has a flexible policy that incorporates new concepts into training programs and offers new options in consultations. (MSE)

Wing, Steve

1997-01-01

182

Strategies for redesigning physician compensation.  

PubMed

Five principles should guide a health system's efforts to redesign its physician compensation plan: Goals should be aligned. Goals should not focus solely on productivity. Metrics should be not only individual, but also team-based. Initial metrics should be selected from among those currently being used. Compensation plans should avoid long-term commitments. PMID:25076639

Corneliuson, Susan K; Hackman, Brian

2014-07-01

183

Compensation: The Impact of Policy.  

ERIC Educational Resources Information Center

Complexity of employee compensation policy is examined as it applies to colleges and universities. It is argued that sound compensation policy helps the institution attract and retain qualified, skilled employees. New approaches that shift the focus from job to employee are outlined, and their implications for institutions of higher education are

Morrell, Louis R.

1994-01-01

184

Changing Conceptions of Employee Compensation  

ERIC Educational Resources Information Center

This paper reviews and discusses many differing forms of incentive compensation systems that are being used in today's organizations. The review traces the roots of bonus compensation from individual piece-work plans through the adoption of organization-wide gain sharing plans to the growing recognition of open-book management. Reasons for the

Dixon, Mark R.; Hayes, Linda J.

2004-01-01

185

How Minnesota Adopted Workers' Compensation  

Microsoft Academic Search

he adoption of workers' compensation in the 1910s represents a significant event in the economic, legal, and political history of the United States. Work- ers' compensation legislation is one of the major tort reforms of this century, shifting liability for workplace accidents from negligence liability to a form of shared strict liability. The legislation marked a radical shift in how

SHAWN EVERETT KANTOR; PRICE V. FISHBACK

186

Failure and Redemption of Multifilter Rotating Shadowband Radiometer (MFRSR)/Normal Incidence Multifilter Radiometer (NIMFR) Cloud Screening: Contrasting Algorithm Performance at Atmospheric Radiation Measurement (ARM) North Slope of Alaska (NSA) and Southern Great Plains (SGP) Sites  

SciTech Connect

Well-known cloud-screening algorithms, which are designed to remove cloud-contaminated aerosol optical depths (AOD) from AOD measurements, have shown great performance at many middle-to-low latitude sites around the world. However, they may occasionally fail under challenging observational conditions, such as when the sun is low (near the horizon) or when optically thin clouds with small spatial inhomogeneity occur. Such conditions have been observed quite frequently at the high-latitude Atmospheric Radiation Measurement (ARM) North Slope of Alaska (NSA) sites. A slightly modified cloud-screening version of the standard algorithm is proposed here with a focus on the ARM-supported Multifilter Rotating Shadowband Radiometer (MFRSR) and Normal Incidence Multifilter Radiometer (NIMFR) data. The modified version uses approximately the same techniques as the standard algorithm, but it additionally examines the magnitude of the slant-path line of sight transmittance and eliminates points when the observed magnitude is below a specified threshold. Substantial improvement of the multi-year (1999-2012) aerosol product (AOD and its Angstrom exponent) is shown for the NSA sites when the modified version is applied. Moreover, this version reproduces the AOD product at the ARM Southern Great Plains (SGP) site, which was originally generated by the standard cloud-screening algorithms. The proposed minor modification is easy to implement and its application to existing and future cloud-screening algorithms can be particularly beneficial for challenging observational conditions.

Kassianov, Evgueni I.; Flynn, Connor J.; Koontz, Annette S.; Sivaraman, Chitra; Barnard, James C.

2013-09-11

187

Transponder-Aided Joint Calibration and Synchronization Compensation for Distributed Radar Systems  

PubMed Central

High-precision radiometric calibration and synchronization compensation must be provided for distributed radar system due to separate transmitters and receivers. This paper proposes a transponder-aided joint radiometric calibration, motion compensation and synchronization for distributed radar remote sensing. As the transponder signal can be separated from the normal radar returns, it is used to calibrate the distributed radar for radiometry. Meanwhile, the distributed radar motion compensation and synchronization compensation algorithms are presented by utilizing the transponder signals. This method requires no hardware modifications to both the normal radar transmitter and receiver and no change to the operating pulse repetition frequency (PRF). The distributed radar radiometric calibration and synchronization compensation require only one transponder, but the motion compensation requires six transponders because there are six independent variables in the distributed radar geometry. Furthermore, a maximum likelihood method is used to estimate the transponder signal parameters. The proposed methods are verified by simulation results. PMID:25794158

Wang, Wen-Qin

2015-01-01

188

Transponder-aided joint calibration and synchronization compensation for distributed radar systems.  

PubMed

High-precision radiometric calibration and synchronization compensation must be provided for distributed radar system due to separate transmitters and receivers. This paper proposes a transponder-aided joint radiometric calibration, motion compensation and synchronization for distributed radar remote sensing. As the transponder signal can be separated from the normal radar returns, it is used to calibrate the distributed radar for radiometry. Meanwhile, the distributed radar motion compensation and synchronization compensation algorithms are presented by utilizing the transponder signals. This method requires no hardware modifications to both the normal radar transmitter and receiver and no change to the operating pulse repetition frequency (PRF). The distributed radar radiometric calibration and synchronization compensation require only one transponder, but the motion compensation requires six transponders because there are six independent variables in the distributed radar geometry. Furthermore, a maximum likelihood method is used to estimate the transponder signal parameters. The proposed methods are verified by simulation results. PMID:25794158

Wang, Wen-Qin

2015-01-01

189

75 FR 53023 - Sound Incentive Compensation Guidance  

Federal Register 2010, 2011, 2012, 2013, 2014

...Office of Thrift Supervision Sound Incentive Compensation Guidance...collection. Title of Proposal: Sound Incentive Compensation Guidance...consistent with the Principles for Sound Compensation Practices adopted...Responses: 40 hours. Estimated Frequency of Response: On...

2010-08-30

190

75 FR 22679 - Sound Incentive Compensation Guidance  

Federal Register 2010, 2011, 2012, 2013, 2014

...Office of Thrift Supervision Sound Incentive Compensation Guidance...collection. Title of Proposal: Sound Incentive Compensation Guidance...consistent with the Principles for Sound Compensation Practices adopted...Responses: 40 hours. Estimated Frequency of Response: On...

2010-04-29

191

75 FR 76079 - Sound Incentive Compensation Guidance  

Federal Register 2010, 2011, 2012, 2013, 2014

...Office of Thrift Supervision Sound Incentive Compensation Guidance...collection. Title of Proposal: Sound Incentive Compensation Guidance...consistent with the Principles for Sound Compensation Practices adopted...Response: 40 hours. Estimated Frequency of Response: On...

2010-12-07

192

33 CFR 136.229 - Compensation allowable.  

Code of Federal Regulations, 2010 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.229 Compensation allowable. The amount of compensation allowable is...

2010-07-01

193

33 CFR 136.217 - Compensation allowable.  

Code of Federal Regulations, 2012 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.217 Compensation allowable. (a) The amount of compensation...

2012-07-01

194

33 CFR 136.235 - Compensation allowable.  

Code of Federal Regulations, 2012 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.235 Compensation allowable. The amount of compensation allowable...

2012-07-01

195

33 CFR 136.241 - Compensation allowable.  

Code of Federal Regulations, 2011 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.241 Compensation allowable. The amount of compensation allowable is...

2011-07-01

196

33 CFR 136.223 - Compensation allowable.  

Code of Federal Regulations, 2014 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.223 Compensation allowable. (a) The amount of compensation...

2014-07-01

197

33 CFR 136.235 - Compensation allowable.  

Code of Federal Regulations, 2013 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.235 Compensation allowable. The amount of compensation allowable...

2013-07-01

198

33 CFR 136.241 - Compensation allowable.  

Code of Federal Regulations, 2014 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.241 Compensation allowable. The amount of compensation allowable is...

2014-07-01

199

33 CFR 136.241 - Compensation allowable.  

Code of Federal Regulations, 2010 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.241 Compensation allowable. The amount of compensation allowable is...

2010-07-01

200

33 CFR 136.241 - Compensation allowable.  

Code of Federal Regulations, 2012 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.241 Compensation allowable. The amount of compensation allowable is...

2012-07-01

201

33 CFR 136.211 - Compensation allowable.  

Code of Federal Regulations, 2014 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.211 Compensation allowable. (a) The amount of compensation...

2014-07-01

202

33 CFR 136.211 - Compensation allowable.  

Code of Federal Regulations, 2011 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.211 Compensation allowable. (a) The amount of compensation...

2011-07-01

203

33 CFR 136.205 - Compensation allowable.  

Code of Federal Regulations, 2011 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.205 Compensation allowable. The amount of compensation...

2011-07-01

204

33 CFR 136.235 - Compensation allowable.  

Code of Federal Regulations, 2010 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.235 Compensation allowable. The amount of compensation allowable...

2010-07-01

205

33 CFR 136.205 - Compensation allowable.  

Code of Federal Regulations, 2014 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.205 Compensation allowable. The amount of compensation...

2014-07-01

206

33 CFR 136.217 - Compensation allowable.  

Code of Federal Regulations, 2011 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.217 Compensation allowable. (a) The amount of compensation...

2011-07-01

207

33 CFR 136.205 - Compensation allowable.  

Code of Federal Regulations, 2013 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT Procedures for Particular Claims 136.205 Compensation allowable. The amount of compensation...

2013-07-01

208

47 CFR 51.221 - Reciprocal compensation.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Reciprocal compensation. 51.221 Section...FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON...51.221 Reciprocal compensation. The rules governing reciprocal compensation are set forth in...

2010-10-01

209

10 CFR 5.515 - Compensation.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Compensation. 5.515 Section 5...Energy NUCLEAR REGULATORY COMMISSION NONDISCRIMINATION ON...Prohibited 5.515 Compensation. A recipient shall not...in rates of pay or other compensation; (b) Results in...

2010-01-01

210

16 CFR 16.16 - Compensation.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Compensation. 16.16...FEDERAL TRADE COMMISSION ORGANIZATION...16.16 Compensation. (a) Committee...by law, the Commission shall not...cost to the Commission. The compensation to be...

2010-01-01

211

Minireview: Sex Differences in Adult and Developing Brains: Compensation, Compensation, Compensation  

E-print Network

Minireview: Sex Differences in Adult and Developing Brains: Compensation, Compensation, Massachusetts 01003 Despite decades of research, we do not know the functional significance of most sex differences in the brain. We are heavily invested in the idea that sex differences in brain struc- ture cause

de Vries, Geert J.

212

[Vestibular compensation studies]. [Vestibular Compensation and Morphological Studies  

NASA Technical Reports Server (NTRS)

The following topics are reported: neurophysiological studies on MVN neurons during vestibular compensation; effects of spinal cord lesions on VNC neurons during compensation; a closed-loop vestibular compensation model for horizontally canal-related MVN neurons; spatiotemporal convergence in VNC neurons; contributions of irregularly firing vestibular afferents to linear and angular VOR's; application to flight studies; metabolic measures in vestibular neurons; immediate early gene expression following vestibular stimulation; morphological studies on primary afferents, central vestibular pathways, vestibular efferent projection to the vestibular end organs, and three-dimensional morphometry and imaging.

Perachio, Adrian A. (Principal Investigator)

1996-01-01

213

Algorithms and Algorithmic Languages.  

ERIC Educational Resources Information Center

This paper is intended as an introduction to a number of problems connected with the description of algorithms and algorithmic languages, particularly the syntaxes and semantics of algorithmic languages. The terms "letter, word, alphabet" are defined and described. The concept of the algorithm is defined and the relation between the algorithm and

Veselov, V. M.; Koprov, V. M.

214

Convection Compensated Electrophoretic NMR  

NASA Astrophysics Data System (ADS)

A novel method of convection compensated ENMR (CC-ENMR) has been developed to detect electrophoretic motion of ionic species in the presence of bulk solution convection. This was accomplished using a gradient moment nulling technique to remove spectral artifacts from heat-induced convection and using the polarity switch of the applied electric field to retain spin phase modulations due to electrophoretic flow. Experiments were carried out with a mixture of 100 mM L-aspartic acid and 100 mM 4,9-dioxa-1,12-dodecanediamine to demonstrate this new method of ENMR. CC-ENMR enhances our previously developed capillary array ENMR (CA-ENMR) in solving the convection problem. The combined CA- and CC-ENMR approach strengthens the potential of multidimensional ENMR in simultaneous structural determination of coexisting proteins and protein conformations in biological buffer solutions of high ionic strength. Structural mapping of interacting proteins during biochemical reactions becomes possible in the future using ENMR techniques, which may have a profound impact on the understanding of biological events, including protein folding, genetic control, and signal transduction in general.

He, Qiuhong; Wei, Zhaohui

2001-06-01

215

Compensated pulsed alternator  

DOEpatents

This invention relates to an electromechanical energy converter with inertial energy storage. The device, a single phase, two or multi-pole alternator with stationary field coils, and a rotating armature is provided. The rotor itself may be of laminated steel for slower pulses or for faster pulses should be nonmagnetic and electrically nonconductive in order to allow rapid penetration of the field as the armature coil rotates. The armature coil comprises a plurality of power generating conductors mounted on the rotor. The alternator may also include a stationary or counterrotating compensating coil to increase the output voltage thereof and to reduce the internal impedance of the alternator at the moment of peak outout. As the machine voltage rises sinusoidally, an external trigger switch is adapted to be closed at the appropriate time to create the desired output current from said alternator to an external load circuit, and as the output current passes through zero a self-commutating effect is provided to allow the switch to disconnect the generator from the external circuit.

Weldon, William F. (Austin, TX); Driga, Mircea D. (Austin, TX); Woodson, Herbert H. (Austin, TX)

1980-01-01

216

Noise reduction of image sequences using H.264\\/AVC variable block-size motion compensation  

Microsoft Academic Search

A variable block-size noise reduction algorithm for image sequences is proposed, in which the variable block-size motion compensation concept in H.264\\/AVC is modified and applied to adaptive filtering. Computer simulations with various test sequences show the effectiveness of the proposed algorithm.

Doo-Hyun Kim; Rae-Hong Park; Seungjoon Yang

2006-01-01

217

Robotic compensation of cerebellar ataxia  

E-print Network

The cerebellum is believed to play a role in dynamic compensation in the human motor control system. When it is damaged, subjects make clumsy movements with reduced acceleration, increased overshoot, and swerving in ...

Smith, Eric D., S.M. Massachusetts Institute of Technology

2007-01-01

218

Fundamentals of compensation and benefits.  

PubMed

The authors discuss the objectives of compensation programs--including direct and indirect forms of reward--and employee motivation. Job descriptions and job evaluations are also explored. PMID:11401793

Diorio, J A; Fallon, L F

2001-01-01

219

Temperature-compensating dc restorer  

NASA Technical Reports Server (NTRS)

Circuit provides stable references restoration in addition to temperature compensation. Possible TV monitor applications include traffic and security surveillance systems, where cameras are subject to environmental extremes, as in unheated warehouses or outdoors.

Thomas, H. M.

1980-01-01

220

Perks and Culture Competitive compensation  

E-print Network

Perks and Culture · Competitive compensation · Relocation packages · Health coverage · 401(k) plan-class experience · Building and integrating technology solutions--front end and back end--that allow third

Ghosh, Joydeep

221

National Compensation Survey Home Page  

NSDL National Science Digital Library

The Bureau of Labor Statistics (BLS) posts this publication online, with sections downloadable as .pdf files. The release, the National Compensation Survey, is a redesign of BLS' compensation statistics to reflect the workplace of the 21st century. From the main page, users can access the full .pdf-format text of the survey results as well as a summary, and a wealth of other related sites and documents.

222

An Alternate Method to Springback Compensation for Sheet Metal Forming  

PubMed Central

The aim of this work is to improve the accuracy of cold stamping product by accommodating springback. This is a numerical approach to improve the accuracy of springback analysis and die compensation process combining the displacement adjustment (DA) method and the spring forward (SF) algorithm. This alternate hybrid method (HM) is conducted by firstly employing DA method followed by the SF method instead of either DA or SF method individually. The springback shape and the target part are used to optimize the die surfaces compensating springback. The hybrid method (HM) algorithm has been coded in Fortran and tested in two- and three-dimensional models. By implementing the HM, the springback error can be decreased and the dimensional deviation falls in the predefined tolerance range. PMID:25165738

Omar, Badrul; Jusoff, Kamaruzaman

2014-01-01

223

An alternate method to springback compensation for sheet metal forming.  

PubMed

The aim of this work is to improve the accuracy of cold stamping product by accommodating springback. This is a numerical approach to improve the accuracy of springback analysis and die compensation process combining the displacement adjustment (DA) method and the spring forward (SF) algorithm. This alternate hybrid method (HM) is conducted by firstly employing DA method followed by the SF method instead of either DA or SF method individually. The springback shape and the target part are used to optimize the die surfaces compensating springback. The hybrid method (HM) algorithm has been coded in Fortran and tested in two- and three-dimensional models. By implementing the HM, the springback error can be decreased and the dimensional deviation falls in the predefined tolerance range. PMID:25165738

Siswanto, Waluyo Adi; Anggono, Agus Dwi; Omar, Badrul; Jusoff, Kamaruzaman

2014-01-01

224

Operational Atmospheric Correction of Landsat TM Data  

Microsoft Academic Search

The recent algorithms developed for biophysical variables assessment require accurate surface reflectance measurements. This article describes algorithms used for atmospheric correction of Landsat Thematic Mapper (TM) data. Atmospheric corrections include Rayleigh scattering, gaseous absorption, and aerosol scattering in three visible channels (480 nm, 560 nm, and 660 nm), and the near-infrared channel (830 nm). Atmospheric constituents such as water vapor

Hassan Ouaidrari; Eric F. Vermote

1999-01-01

225

Compensating For Changes in MOS Sensors  

SciTech Connect

AirAdvice provided the following introduction: AirAdvice uses metal oxide semiconductor (MOS) sensors for measuring total volatile organic compounds (TVOC) in air. These sensors are incorporated into AirAdvices indoor air quality (IAQ) monitors. The IAQ monitors are designed so that they require annual calibration to maintain acceptable accuracy. Since the MOS TVOC sensors used in the monitors change in sensitivity with time and exposure to gases, AirAdvice has developed an algorithm-based process that automatically compensates for changes in the sensors. The proposed project is to have PNNL analyze data provided by AirAdvice with these objectives: (1) assess how effective AirAdvices automatic drift correction process is, (2) identify any problems in the process, and (3) propose improvements to the process.

Matzke, Brett D.

2006-09-29

226

Compensation, radiographic changes, and survival in applicants for asbestosis compensation.  

PubMed Central

The survival of 354 claimants for compensation for pulmonary asbestosis among former workers of the Wittenoom crocidolite mine and mill in Western Australia has been examined. There were 118 deaths up to December 1982. The median time between start of work and claim for compensation was 17 years. The standardised mortality ratio (SMR) for deaths from all causes was 2.65 (p less than 0.0001). The SMR for pneumoconiosis was 177.2 (p less than 0.0001), bronchitis and emphysema 2.6 (p = 0.04), tuberculosis 44.6 (p less than 0.0001), respiratory cancer (including five deaths from malignant pleural mesothelioma) 6.4 (p less than 0.0001), gastrointestinal cancer 1.6 (p = 0.22), all other cancers 1.6 (p = 0.17), heart disease 1.4 (p = 0.07), and all other causes 2.18 (p = 0.004). Plain chest radiographs taken within two years of claiming compensation were found for 238 subjects and were categorised independently by two observers according to the International Labour Organisation criteria without knowledge of exposure or compensation details. Profusion of radiographic opacities, age at claiming compensation, work in the Wittenoom mill, and degree of disability awarded by the pneumoconiosis medical board were significant predictors of survival, but total estimated exposure to asbestos was not. Radiographic profusion and degree of disability were, however, predictable by total exposure. The median survival from claim for compensation was 17 years in subjects with ILO category 1 pneumoconiosis, 12 years in category 2, and three years in category 3. PMID:2990524

Cookson, W O; Musk, A W; Glancy, J J; de Klerk, N H; Yin, R; Mele, R; Carr, N G; Armstrong, B K; Hobbs, M S

1985-01-01

227

Atmospheric and adaptive optics  

NASA Astrophysics Data System (ADS)

Atmospheric optics is the study of optical effects induced by the atmosphere on light propagating from distant sources. Of particular concern to astronomers is atmospheric turbulence, which limits the performance of ground-based telescopes. The past two decades have seen remarkable growth in the capabilities and performance of adaptive optics (AO) systems. These opto-mechanical systems actively compensate for the blurring effect of the Earth's turbulent atmosphere. By sensing, and correcting, wavefront distortion introduced by atmospheric index-of-refraction variations, AO systems can produce images with resolution approaching the diffraction limit of the telescope at near-infrared wavelengths. This review highlights the physical processes and fundamental relations of atmospheric optics that are most relevant to astronomy, and discusses the techniques used to characterize atmospheric turbulence. The fundamentals of AO are then introduced and the many types of advanced AO systems that have been developed are described. The principles of each are outlined, and the performance and limitations are examined. Aspects of photometric and astrometric measurements of AO-corrected images are considered. The paper concludes with a discussion of some of the challenges related to current and future AO systems, particularly those that will equip the next generation of large, ground-based optical and infrared telescopes.

Hickson, Paul

2014-11-01

228

Switching sequence optimization for gradient error compensation in thermometer-decoded DAC arrays  

Microsoft Academic Search

This paper discusses switching schemes for gradient error compensation in unary (thermometer-decoded) arrays of digital-to-analog converters (DACs). The absolute lower bound of integral nonlinearity (INL) by optimizing switching sequences is established and optimal switching sequences that meet the lower bound of INL are presented for linear error compensation in one-dimensional arrays. A rapidly converging algorithm is developed to obtain INL

Yonghua Cong; Randall L. Geiger

2000-01-01

229

Clouds and the Earth's Radiant Energy System (CERES) algorithm theoretical basis document. volume 4; Determination of surface and atmosphere fluxes and temporally and spatially averaged products (subsystems 5-12); Determination of surface and atmosphere fluxes and temporally and spatially averaged products  

NASA Technical Reports Server (NTRS)

The theoretical bases for the Release 1 algorithms that will be used to process satellite data for investigation of the Clouds and the Earth's Radiant Energy System (CERES) are described. The architecture for software implementation of the methodologies is outlined. Volume 4 details the advanced CERES techniques for computing surface and atmospheric radiative fluxes (using the coincident CERES cloud property and top-of-the-atmosphere (TOA) flux products) and for averaging the cloud properties and TOA, atmospheric, and surface radiative fluxes over various temporal and spatial scales. CERES attempts to match the observed TOA fluxes with radiative transfer calculations that use as input the CERES cloud products and NOAA National Meteorological Center analyses of temperature and humidity. Slight adjustments in the cloud products are made to obtain agreement of the calculated and observed TOA fluxes. The computed products include shortwave and longwave fluxes from the surface to the TOA. The CERES instantaneous products are averaged on a 1.25-deg latitude-longitude grid, then interpolated to produce global, synoptic maps to TOA fluxes and cloud properties by using 3-hourly, normalized radiances from geostationary meteorological satellites. Surface and atmospheric fluxes are computed by using these interpolated quantities. Clear-sky and total fluxes and cloud properties are then averaged over various scales.

Wielicki, Bruce A. (Principal Investigator); Barkstrom, Bruce R. (Principal Investigator); Baum, Bryan A.; Charlock, Thomas P.; Green, Richard N.; Lee, Robert B., III; Minnis, Patrick; Smith, G. Louis; Coakley, J. A.; Randall, David R.

1995-01-01

230

38 CFR 3.351 - Special monthly dependency and indemnity compensation, death compensation, pension and spouse's...  

Code of Federal Regulations, 2010 CFR

38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01...indemnity compensation, death compensation, pension and spouse's compensation ratings. 3.351 Section 3.351 Pensions, Bonuses, and Veterans' Relief...

2010-07-01

231

Compensation for electrical converter nonlinearities  

DOEpatents

Systems and methods are provided for delivering energy from an input interface to an output interface. An electrical system includes an input interface, an output interface, an energy conversion module between the input interface and the output interface, an inductive element between the input interface and the energy conversion module, and a control module. The control module determines a compensated duty cycle control value for operating the energy conversion module to produce a desired voltage at the output interface and operates the energy conversion module to deliver energy to the output interface with a duty cycle that is influenced by the compensated duty cycle control value. The compensated duty cycle control value is influenced by the current through the inductive element and accounts for voltage across the switching elements of the energy conversion module.

Perisic, Milun; Ransom, Ray M; Kajouke, Lateef A

2013-11-19

232

Improved Methodology for Surface and Atmospheric Soundings, Error Estimates, and Quality Control Procedures: the AIRS Science Team Version-6 Retrieval Algorithm  

NASA Technical Reports Server (NTRS)

The AIRS Science Team Version-6 AIRS/AMSU retrieval algorithm is now operational at the Goddard DISC. AIRS Version-6 level-2 products are generated near real-time at the Goddard DISC and all level-2 and level-3 products are available starting from September 2002. This paper describes some of the significant improvements in retrieval methodology contained in the Version-6 retrieval algorithm compared to that previously used in Version-5. In particular, the AIRS Science Team made major improvements with regard to the algorithms used to 1) derive surface skin temperature and surface spectral emissivity; 2) generate the initial state used to start the cloud clearing and retrieval procedures; and 3) derive error estimates and use them for Quality Control. Significant improvements have also been made in the generation of cloud parameters. In addition to the basic AIRS/AMSU mode, Version-6 also operates in an AIRS Only (AO) mode which produces results almost as good as those of the full AIRS/AMSU mode. This paper also demonstrates the improvements of some AIRS Version-6 and Version-6 AO products compared to those obtained using Version-5.

Susskind, Joel; Blaisdell, John; Iredell, Lena

2014-01-01

233

Multivariable adaptive algorithms for reconfigurable flight control  

Microsoft Academic Search

The application of multivariable adaptive control techniques to flight control reconfiguration is considered. The objective is to redesign automatically flight control laws to compensate for actuator failures or surface damage. Three adaptive algorithms for multivariable model reference control are compared. The availability of state measurements in this application leads to relatively simple algorithms. The respective advantages and disadvantages of the

Marc Bodson; Joseph E. Groszkiewicz

1997-01-01

234

Retrieval of atmospheric and ocean surface parameters from ADEOS-II Advanced Microwave Scanning Radiometer (AMSR) data: Comparison of errors of global and regional algorithms  

Microsoft Academic Search

Retrieval of the sea surface temperature ts, wind speed W, total atmospheric water vapor content V, and total cloud liquid water content Q over the ocean from the simulated ADEOS-II AMSR data in the absence of precipitation is considered. The brightness temperatures (TB) with the vertical (V) and horizontal (H) polarizations at the AMSR frequencies ? = 6.9, 10.7, 18.7,

Leonid M. Mitnik; Maia L. Mitnik

2003-01-01

235

Perks and Culture Competitive compensation  

E-print Network

Perks and Culture · Competitive compensation · Comprehensive training programs · Healthcare coverage · Inclusive & team oriented work environment · Tuition reimbursement · Employee resource groupsCts · Positive train Control - Mandated by the federal government, PTC requires that a train must stop before

Ghosh, Joydeep

236

Concealing compensation from the IRS.  

PubMed

Tougher reporting requirements from the Internal Revenue Service are prompting some not-for-profit hospitals to seek ways to hide compensation arrangements from the public and the media. Critics believe those tactics could get hospitals in hot water with the law, especially now that the IRS has launched a new, aggressive auditing offensive. PMID:10108763

Burda, D; Greene, J

1991-01-28

237

Can Education Compensate for Society?  

ERIC Educational Resources Information Center

The extent to which education can compensate for social disadvantage is a matter of political controversy, especially in the context of policies for social mobility. On the one hand, to blame poor achievement on social class or poverty was seen to dodge the professional responsibility of teachers. On the other, the strong correlation between

Pring, Richard

2011-01-01

238

Altitude Compensating Nozzle Concepts Evaluation  

NASA Technical Reports Server (NTRS)

This report contains the summary of work accomplished during summer of 2000 by Mr. Chad Hammons, undergraduate senior student, Mississippi State University/ERC in support of NASA/MSFC mission pertinent to Altitude compensating nozzle concepts evaluations. In particular, the development of automatic grid generator applicable in conducting sensitivity analysis involving Aerospike engine is described.

Soni, Bharat

2000-01-01

239

New Perspectives on Compensation Strategies.  

ERIC Educational Resources Information Center

Low compensation, in both earnings and benefits, and the resulting high turnover of staff and low quality of programs in early childhood care and education are a national problem. Noting that how we define and view the problem, and the strategies we adopt to solve it, may differ depending on perspectives and disciplines, this paper expands the

Mitchell, Anne; Morgan, Gwen

240

Strategic Design of Teacher Compensation  

ERIC Educational Resources Information Center

Spurred by the national focus on revitalizing the teacher evaluation and support/development process, as well as the current economic downturn, many school districts are reviewing how teachers are compensated. While a few courageous districts have completely upended current structures, most districts are undertaking changes that leave the most

Shields, Regis

2012-01-01

241

Synchrony - Cyberknife Respiratory Compensation Technology  

SciTech Connect

Studies of organs in the thorax and abdomen have shown that these organs can move as much as 40 mm due to respiratory motion. Without compensation for this motion during the course of external beam radiation therapy, the dose coverage to target may be compromised. On the other hand, if compensation of this motion is by expansion of the margin around the target, a significant volume of normal tissue may be unnecessarily irradiated. In hypofractionated regimens, the issue of respiratory compensation becomes an important factor and is critical in single-fraction extracranial radiosurgery applications. CyberKnife is an image-guided radiosurgery system that consists of a 6-MV LINAC mounted to a robotic arm coupled through a control loop to a digital diagnostic x-ray imaging system. The robotic arm can point the beam anywhere in space with 6 degrees of freedom, without being constrained to a conventional isocenter. The CyberKnife has been recently upgraded with a real-time respiratory tracking and compensation system called Synchrony. Using external markers in conjunction with diagnostic x-ray images, Synchrony helps guide the robotic arm to move the radiation beam in real time such that the beam always remains aligned with the target. With the aid of Synchrony, the tumor motion can be tracked in three-dimensional space, and the motion-induced dosimetric change to target can be minimized with a limited margin. The working principles, advantages, limitations, and our clinical experience with this new technology will be discussed.

Ozhasoglu, Cihat [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA (United States)], E-mail: ozhasogluc@upmc.edu; Saw, Cheng B.; Chen Hungcheng; Burton, Steven; Komanduri, Krishna; Yue, Ning J.; Huq, Saiful M.; Heron, Dwight E. [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA (United States)

2008-07-01

242

Compensation in the Nonprofit Sector  

Microsoft Academic Search

We investigate the determinants of pay in the nonprofit sector using data for 2555 year olds from the 1994 88 Current Population Survey Outgoing Rotation Groups. Our results are consistent with the hypothesis that compensation is primarily determined in competitive markets without labor donations to nonprofit employers. One implication is that nonprofit workers receive virtually the same wages as

Christopher J. Ruhm; Carey Borkoski

2003-01-01

243

Compensation of Navajo Uranium Miners  

NSDL National Science Digital Library

This site addresses policy issues of the compensation of Navajo uranium miners. The site provides an annotated index of current issues, legislation, papers and presentations, books, and links that lead to more information on uranium miners. Imbedded links throughout the text lead to related information.

World Information Service on Energy Uranium Project

244

Ongoing transients in carbonate compensation  

Microsoft Academic Search

Uptake of anthropogenic CO2 is acidifying the oceans. Over the next 2000 years, this will modify the dissolution and preservation of sedimentary carbonate. By coupling new formulas for the positions of the calcite saturation horizon, zsat, the compensation depth, zcc, and the snowline, zsnow, to a biogeochemical model of the oceanic carbonate system, we evaluate how these horizons will change

Bernard P. Boudreau; Jack J. Middelburg; Andreas F. Hofmann; Filip J. R. Meysman

2010-01-01

245

TMJ syndrome: is it compensable?  

PubMed

Temporomandibular joint (TMJ) syndrome has only recently surfaced as a workers' compensation or auto accident claim in the insurance industry. It usually appears as a secondary problem to cervical injuries. Further research is needed to establish guidelines for determining whether TMJ syndrome is compensable, but a survey of healthcare practitioners who deal with TMJ--such as the one described in this article--can help in making a determination until guidelines are established. In early 1990, the American Academy of Craniomandibular Disorders and the American Dental Association published guidelines; however, these guidelines address only diagnosis and treatment (Independent Medical and Dental Consultants, Inc., 1990). Further information is needed concerning TMJ's causes and whether the condition should be compensated. Sixty survey questionnaires were sent out to dentists and oral surgeons to identify causes of TMJ, symptoms, diagnostic methods, and treatment. The primary question for which the survey sought an answer was how to judge whether a person with a cervical injury complicated by TMJ syndrome should be compensated for TMJ problems. The remaining questions and answers concerned the medical management of patients with TMJ syndrome. PMID:1824879

Doerrer, A; Figart, F

1991-01-01

246

Unemployment Compensation and Older Workers  

Microsoft Academic Search

Unemployment compensation in the United States is provided through a federal-state system of unemployment insurance (UI). UI provides temporary partial wage replacement to active job seekers who are involuntarily out of work. For older workers, UI is an important source of income security and a potential influence on work incentives. For many, the transition from full-time work in a career

Christopher J. OLeary; Stephen A. Wandner

2000-01-01

247

Compensation strategy in transnational corporations  

Microsoft Academic Search

Forces associated with globalization have facilitated the development of transnational corporations (TNCs). Such companies have a geocentric orientation and attempt to be responsive to both national markets, while simultaneously seeking global coordination. In this paper we propose that such companies need to reconsider the traditional balance sheet approach to expatriate compensation. Accordingly, we suggest that transnational corporations need to engage

Larry Phillips; Mark A. Fox

2003-01-01

248

Compensating Differentials for Sexual Harassment  

Microsoft Academic Search

Workplace sexual harassment is illegal, but many workers report that they have been sexually harassed. Exposure to the risk of sexual harassment may decrease productivity, which would reduce wages. Alternatively, workers may receive a compensating differential for exposure to sexual harassment, which would increase wages. Data on claims of sexual harassment filed with the Equal Employment Opportunity Commission are used

Joni Hersch

2011-01-01

249

Motion Compensated Interframe Image Prediction  

Microsoft Academic Search

Interframe motion estimation of subblocks based on improved search techniques is developed. These techniques are based on minimizing the mean difference between the subblock in question in the present frame and the displaced subblock in the previous frame. The performance of the motion compensated prediction developed here is investigated for various block sizes and is compared to other techniques.

S. Kappagantula; K. R. Rao

1985-01-01

250

Merit Compensation and Higher Education.  

ERIC Educational Resources Information Center

The concept of merit compensation is clarified from both administrative and faculty perspectives, and the conceptual sources of the controversy surrounding "merit" are addressed. Using the lexical tradition of the verb "to merit," four distinct semantic components are identified: to earn, to deserve, to value or give preference, and to obtain

Counelis, James Steve

251

Using a Quadtree Algorithm To Assess Line of Sight  

NASA Technical Reports Server (NTRS)

A matched pair of computer algorithms determines whether line of sight (LOS) is obstructed by terrain. These algorithms were originally designed for use in conjunction with combat-simulation software in military training exercises, but could also be used for such commercial purposes as evaluating lines of sight for antennas or determining what can be seen from a "room with a view." The quadtree preparation algorithm operates on an array of digital elevation data and only needs to be run once for a terrain region, which can be quite large. Relatively little computation time is needed, as each elevation value is considered only one and one-third times. The LOS assessment algorithm uses that quadtree to answer LOS queries. To determine whether LOS is obstructed, a piecewise-planar (or higher-order) terrain skin is computationally draped over the digital elevation data. Adjustments are made to compensate for curvature of the Earth and for refraction of the LOS by the atmosphere. Average computing time appears to be proportional to the number of queries times the logarithm of the number of elevation data points. Accuracy is as high as is possible for the available elevation data, and symmetric results are assured. In the simulation, the LOS query program runs as a separate process, thereby making more random-access memory available for other computations.

Gonzalez, Joseph; Chamberlain, Robert; Tailor, Eric; Gutt, Gary

2006-01-01

252

39 CFR 3050.27 - Workers' Compensation Report.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Workers' Compensation Report. 3050.27 ...Service POSTAL REGULATORY COMMISSION PERSONNEL PERIODIC...3050.27 Workers' Compensation Report. The Workers' Compensation Report, including...

2010-07-01

253

A Cenozoic record of the equatorial Pacific carbonate compensation depth.  

PubMed

Atmospheric carbon dioxide concentrations and climate are regulated on geological timescales by the balance between carbon input from volcanic and metamorphic outgassing and its removal by weathering feedbacks; these feedbacks involve the erosion of silicate rocks and organic-carbon-bearing rocks. The integrated effect of these processes is reflected in the calcium carbonate compensation depth, which is the oceanic depth at which calcium carbonate is dissolved. Here we present a carbonate accumulation record that covers the past 53 million years from a depth transect in the equatorial Pacific Ocean. The carbonate compensation depth tracks long-term ocean cooling, deepening from 3.0-3.5?kilometres during the early Cenozoic (approximately 55?million years ago) to 4.6 kilometres at present, consistent with an overall Cenozoic increase in weathering. We find large superimposed fluctuations in carbonate compensation depth during the middle and late Eocene. Using Earth system models, we identify changes in weathering and the mode of organic-carbon delivery as two key processes to explain these large-scale Eocene fluctuations of the carbonate compensation depth. PMID:22932385

Plike, Heiko; Lyle, Mitchell W; Nishi, Hiroshi; Raffi, Isabella; Ridgwell, Andy; Gamage, Kusali; Klaus, Adam; Acton, Gary; Anderson, Louise; Backman, Jan; Baldauf, Jack; Beltran, Catherine; Bohaty, Steven M; Bown, Paul; Busch, William; Channell, Jim E T; Chun, Cecily O J; Delaney, Margaret; Dewangan, Pawan; Dunkley Jones, Tom; Edgar, Kirsty M; Evans, Helen; Fitch, Peter; Foster, Gavin L; Gussone, Nikolaus; Hasegawa, Hitoshi; Hathorne, Ed C; Hayashi, Hiroki; Herrle, Jens O; Holbourn, Ann; Hovan, Steve; Hyeong, Kiseong; Iijima, Koichi; Ito, Takashi; Kamikuri, Shin-ichi; Kimoto, Katsunori; Kuroda, Junichiro; Leon-Rodriguez, Lizette; Malinverno, Alberto; Moore, Ted C; Murphy, Brandon H; Murphy, Daniel P; Nakamura, Hideto; Ogane, Kaoru; Ohneiser, Christian; Richter, Carl; Robinson, Rebecca; Rohling, Eelco J; Romero, Oscar; Sawada, Ken; Scher, Howie; Schneider, Leah; Sluijs, Appy; Takata, Hiroyuki; Tian, Jun; Tsujimoto, Akira; Wade, Bridget S; Westerhold, Thomas; Wilkens, Roy; Williams, Trevor; Wilson, Paul A; Yamamoto, Yuhji; Yamamoto, Shinya; Yamazaki, Toshitsugu; Zeebe, Richard E

2012-08-30

254

22 CFR 96.34 - Compensation.  

Code of Federal Regulations, 2011 CFR

...THE INTERCOUNTRY ADOPTION ACT OF 2000 (IAA) Standards for Convention Accreditation and Approval Financial and Risk Management 96.34 Compensation. (a) The agency or person does not compensate any individual who provides...

2011-04-01

255

22 CFR 96.34 - Compensation.  

Code of Federal Regulations, 2012 CFR

...THE INTERCOUNTRY ADOPTION ACT OF 2000 (IAA) Standards for Convention Accreditation and Approval Financial and Risk Management 96.34 Compensation. (a) The agency or person does not compensate any individual who provides...

2012-04-01

256

22 CFR 96.34 - Compensation.  

Code of Federal Regulations, 2014 CFR

...THE INTERCOUNTRY ADOPTION ACT OF 2000 (IAA) Standards for Convention Accreditation and Approval Financial and Risk Management 96.34 Compensation. (a) The agency or person does not compensate any individual who provides...

2014-04-01

257

16 CFR 1105.11 - Compensable costs.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Compensable costs. 1105.11 Section 1105... CONSUMER PRODUCT SAFETY ACT REGULATIONS CONTRIBUTIONS TO COSTS OF PARTICIPANTS IN DEVELOPMENT... 1105.11 Compensable costs. The Commission may...

2010-01-01

258

7 CFR 930.133 - Compensation rate.  

Code of Federal Regulations, 2012 CFR

...OF AGRICULTURE TART CHERRIES GROWN IN THE STATES OF MICHIGAN, NEW YORK, PENNSYLVANIA, OREGON, UTAH, WASHINGTON, AND WISCONSIN Administrative Rules and Regulations 930.133 Compensation rate. A compensation rate of $250 per...

2012-01-01

259

33 CFR 136.113 - Other compensation.  

Code of Federal Regulations, 2012 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT General Procedure 136.113 Other compensation. A claimant must include an accounting, including the source...

2012-07-01

260

33 CFR 136.113 - Other compensation.  

Code of Federal Regulations, 2013 CFR

...FINANCIAL RESPONSIBILITY AND COMPENSATION OIL SPILL LIABILITY TRUST FUND; CLAIMS PROCEDURES; DESIGNATION OF SOURCE; AND ADVERTISEMENT General Procedure 136.113 Other compensation. A claimant must include an accounting, including the source...

2013-07-01

261

Lamb wave dispersion compensation in piezoelectric wafer active sensor phased-array applications  

NASA Astrophysics Data System (ADS)

Lamb-wave testing for structural health monitoring is complicated by the dispersion nature of the wave modes. The dispersion effect will result in a propagated wave with longer time duration, deformed envelop shape as compared to its excitation counterpart, and hard to be interpreted. This paper first reviews the dispersion compensation and removal algorithms. Second, it compares these two methods by applying them to two widely used low-frequency Lamb wave modes: S0 and A0. Numerical simulations are compared in parallel with experimental results. Finally, the dispersion compensation algorithm is applied to 1-D PWAS phased array and demonstrated to improve the phase array's spatial resolution.

Xu, Buli; Yu, Lingyu; Giurgiutiu, Victor

2009-03-01

262

Building the right physician compensation model.  

PubMed

In using benchmark data from physician surveys to establish physician compensation, hospitals should follow six guidelines: Know what the benchmark data represent and how they are computed. Use all resources available in setting physician compensation. Carefully determine whether the median work relative value unit should be used. Beware of applying consistent compensation models across specialties. Be careful not to change the compensation rates annually. Think holistically. PMID:25076637

Chamblee, Justin

2014-07-01

263

Jovian atmospheres  

SciTech Connect

A conference on the atmosphere of Jupiter produced papers in the areas of thermal and ortho-para hydrogen structure, clouds and chemistry, atmospheric structure, global dynamics, synoptic features and processes, atmospheric dynamics, and future spaceflight opportunities. A session on the atmospheres of Uranus and Neptune was included, and the atmosphere of Saturn was discussed in several papers.

Allison, M.; Travis, L.D.

1986-10-01

264

Bankers' compensation and fair value accounting  

Microsoft Academic Search

This paper examines the role of certain fair value accounting (FVA) outcomes in compensation of US bank CEOs. The use of FVA in compensation invites an agency costthe clawback problemif cash compensation is based on unrealized profits that may reverse in the future. At the same time FVA may be a good measure of current managerial effort and so be

Gilad Livne; Garen Markarian; Alistair Milne

2011-01-01

265

Environmental compensation in Swedish road planning  

Microsoft Academic Search

Environmental compensation has been discussed in Europe for a long time and in the Swedish context for almost a decade, but it was not until the latest environmen- tal legislation came into force in 1999 that it became easier to formally require compensation for loss of environmental value. The use of compensation can be one method in trying to reach

Kristina Rundcrantz

2006-01-01

266

Reset compensation applied on industrial heat exchangers  

Microsoft Academic Search

This work aims at improving the control of an industrial heat exchanger used in the thermal treatment in food industry. The goal is to investigate the potentials of a hybrid compensator previously developed by the authors, the PI+CI reset compensator, in the robust control when significant uncertainty is present. To this end, a PI+CI compensator has been designed by using

Angel Vidal; A. Banos

2009-01-01

267

Salesforce Compensation Plans: An Agency Theoretic Perspective  

Microsoft Academic Search

A theory of salesforce compensation plans is presented where the sales of a product depend not only on the salesperson's effort but also on the uncertainty in the selling environment. The firm chooses a compensation plan to maximize its profit taking into account the salesperson's likely effort levels under alternative compensation plans and his or her alternative job opportunities. The

Amiya K. Basu; Rajiv Lal; V. Srinivasan; Richard Staelin

1985-01-01

268

Avian sex chromosomes: dosage compensation matters.  

E-print Network

of such dosage compensated genes can be found on the short arm of the Z chromosome. The implications of this new picture of avian dosage compensation for avian sex determination are discussed, along with a possible mechanism of avian dosage compensation....

McQueen, Heather A; Clinton, Michael

2009-01-01

269

2003 Nebraska Ag Worker Compensation Requirements  

Microsoft Academic Search

The purpose of the Nebraska worker compensation program is to provide no-fault compensation to employees injured on the job. Traditionally farm and ranch workers have been exempted from Nebraska worker compensation statutes, despite the fact that agriculture is one of Nebraskas most dangerous industries. For many years the Supreme Court has interpreted the farm and ranch worker exemption narrowly in

dave Aiken

2003-01-01

270

Undergraduate Atmospheric  

E-print Network

-Exploration Planetary Science-Observation Minor Programs Earth, Atmospheric, and Planetary Sciences AstronomyUndergraduate Handbook Earth, Atmospheric and Planetary Sciences #12;EAPS Undergraduate Program, atmospheric science, oceanography, climate, planetary science, and astronomy. The Department's flexible

Rothman, Daniel

271

38 CFR 3.658 - Offsets; dependency and indemnity compensation.  

Code of Federal Regulations, 2010 CFR

...covering a period for which death compensation or benefits under the Federal Employee's Compensation...to an offset of payments of death compensation or benefits under the Federal Employees' Compensation Act over the same period....

2010-07-01

272

28 CFR 104.21 - Filing for compensation.  

Code of Federal Regulations, 2010 CFR

...COMPENSATION FUND OF 2001 Filing for Compensation; Application for Advance Benefits 104.21 Filing for compensation. (a) Compensation form; filing. Except for applications for Advance Benefits pursuant to 104.22,...

2010-07-01

273

Causal compensated perturbations in cosmology  

NASA Technical Reports Server (NTRS)

A theoretical framework is developed to calculate linear perturbations in the gravitational and matter fields which arise causally in response to the presence of stiff matter sources in a FRW cosmology. It is shown that, in order to satisfy energy and momentum conservation, the gravitational fields of the source must be compensated by perturbations in the matter and gravitational fields, and the role of such compensation in containing the initial inhomogeneities in their subsequent evolution is discussed. A complete formal solution is derived in terms of Green functions for the perturbations produced by an arbitrary source in a flat universe containing cold dark matter. Approximate Green function solutions are derived for the late-time density perturbations and late-time gravitational waves in a universe containing a radiation fluid. A cosmological energy-momentum pseudotensor is defined to clarify the nature of energy and momentum conservation in the expanding universe.

Veeraraghavan, Shoba; Stebbins, Albert

1990-01-01

274

Active tremor compensation in microsurgery  

Microsoft Academic Search

This work presents the development of an intelligent microsurgical instrument to perform real-time tremor compensation within a handheld tool. The intelligent instrument senses its own motion, distinguishes between voluntary and erroneous motion, and manipulates its tip to cancel the undesired component in real-time. The on-board sensing unit is made up of a magnetometer-aided all-accelerometer inertial measurement unit and sensor fusion

W. T. Ang; P. K. Pradeep; C. N. Riviere

2004-01-01

275

Birefringence compensated arrayed waveguide grating  

NASA Astrophysics Data System (ADS)

In this paper we review our work on birefringence compensated arrayed waveguide grating. We elaborate on a birefringence compensation technique based on angled star couplers in arrayed waveguide grating (AWG) and discuss several demonstrations both in low-index-contrast and high-index-contrast material systems. A 16-channel AWG with 100GHz channel spacing for DWDM application is designed and fabricated in silica-based low-index-contrast waveguide. The experimental results confirm that the polarization-dependent wavelength shift (PD?) can be tuned by varying the incident/diffraction angle at the star couplers and a birefringence-free property can be achieved without additional fabrication process as compared to conventional AWG. A further validation of this technique is demonstrated in high-index-contrast silicon-on-insulator waveguide, in combination with different diffraction orders for TE and TM polarizations. A birefringence compensated silicon nanowire AWG for CWDM optical interconnects is designed and fabricated. The theoretical and experimental results show that the PD? can be reduced from 380-420nm to 0.5-3.5 nm, below 25% of the 3 dB bandwidth of the channel response in the wavelength range of 1500 to 1600nm.

Zou, Jun; Xia, Xiang; Lang, Tingting; He, Jian-Jun

2014-10-01

276

Compensation Techniques in Accelerator Physics  

SciTech Connect

Accelerator physics is one of the most diverse multidisciplinary fields of physics, wherein the dynamics of particle beams is studied. It takes more than the understanding of basic electromagnetic interactions to be able to predict the beam dynamics, and to be able to develop new techniques to produce, maintain, and deliver high quality beams for different applications. In this work, some basic theory regarding particle beam dynamics in accelerators will be presented. This basic theory, along with applying state of the art techniques in beam dynamics will be used in this dissertation to study and solve accelerator physics problems. Two problems involving compensation are studied in the context of the MEIC (Medium Energy Electron Ion Collider) project at Jefferson Laboratory. Several chromaticity (the energy dependence of the particle tune) compensation methods are evaluated numerically and deployed in a figure eight ring designed for the electrons in the collider. Furthermore, transverse coupling optics have been developed to compensate the coupling introduced by the spin rotators in the MEIC electron ring design.

Hisham Kamal Sayed

2011-05-31

277

Adaptive beamformer delay compensation for active sonar  

NASA Astrophysics Data System (ADS)

Delay compensation as a preliminary step to adaptive beamforming (ABF) is described. Such compensation can be used for linear or planar arrays whenever the temporal width of a signal's matched-filter output peak is significantly shorter than the propagation time across the array. Preliminary delay compensation is not normally used in passive ABF processing since the signals being processed are usually steady-state or can be regarded as such. However, when transient events much be processed, such as those associated with either impulsive echoes or with matched-filter outputs of large TW signals, then compensation prior to ABF may be required in order to obtain the full array gain for the signal of interest. Methods for achieving wide-band delay compensation are described, the parameters associated with defining the minimal compensation required are explained, and losses suffered when compensation is not used are discussed.

Alsup, James M.

1994-10-01

278

Transport delay compensation for computer-generated imagery systems  

NASA Technical Reports Server (NTRS)

In the problem of pure transport delay in a low-pass system, a trade-off exists with respect to performance within and beyond a frequency bandwidth. When activity beyond the band is attenuated because of other considerations, this trade-off may be used to improve the performance within the band. Specifically, transport delay in computer-generated imagery systems is reduced to a manageable problem by recognizing frequency limits in vehicle activity and manual-control capacity. Based on these limits, a compensation algorithm has been developed for use in aircraft simulation at NASA Ames Research Center. For direct measurement of transport delays, a beam-splitter experiment is presented that accounts for the complete flight simulation environment. Values determined by this experiment are appropriate for use in the compensation algorithm. The algorithm extends the bandwidth of high-frequency flight simulation to well beyond that of normal pilot inputs. Within this bandwidth, the visual scene presentation manifests negligible gain distortion and phase lag. After a year of utilization, two minor exceptions to universal simulation applicability have been identified and subsequently resolved.

Mcfarland, Richard E.

1988-01-01

279

Real-time compensation for tool form errors in turning using computer vision  

SciTech Connect

Deviations from the circular shape of the cutting edge of a single-point turning tool cause form errors in the workpiece during contour cutting. One can compensate for these tool-form errors by determining the size of the effective deviation at a particular instant during cutting, and then adjusting the position of the cutting tool accordingly. An algorithm for the compensation of tool-nose-radius errors in real time has been developed and implemented on a CNC fuming center. A previously developed computer-vision-based tool- inspection system is used to determine the size of the deviations. Information from this system is fed to the error compensation computer which modifies the tool path in real time. Workpieces were cut utilizing the compensation system and were inspected on a coordinate measuring machine. Significant improvements in workpiece form were obtained.

Nobel, G.; Donmez, M.A.; Burton, R.

1990-12-31

280

Real-time compensation for tool form errors in turning using computer vision  

SciTech Connect

Deviations from the circular shape of the cutting edge of a single-point turning tool cause form errors in the workpiece during contour cutting. One can compensate for these tool-form errors by determining the size of the effective deviation at a particular instant during cutting, and then adjusting the position of the cutting tool accordingly. An algorithm for the compensation of tool-nose-radius errors in real time has been developed and implemented on a CNC fuming center. A previously developed computer-vision-based tool- inspection system is used to determine the size of the deviations. Information from this system is fed to the error compensation computer which modifies the tool path in real time. Workpieces were cut utilizing the compensation system and were inspected on a coordinate measuring machine. Significant improvements in workpiece form were obtained.

Nobel, G.; Donmez, M.A.; Burton, R.

1990-01-01

281

An investigation of Bjerknes Compensation in the Southern Ocean in the CCSM4  

SciTech Connect

This project aims to understand the relationship between poleward oceanic and atmospheric heat transport in the Southern Ocean by analyzing output from the community Climate System Model Version 4 (CCSM4). In particular, time series of meridional heat transport in both the atmosphere and the ocean are used to study whether variability in ocean heat transport is balanced by opposing changes in atmospheric heat transport, called Bjerknes Compensation. It is shown that the heat storage term in the Southern Ocean has a significant impact on the oceanic heat budget; as a result, no robust coherences between oceanic and atmospheric heat transports could be found at these southern latitudes.

Weijer, Wilbert [Los Alamos National Laboratory; Kinstle, Caroline M. [Los Alamos National Laboratory

2012-08-28

282

A smart high accuracy silicon piezoresistive pressure sensor temperature compensation system.  

PubMed

Theoretical analysis in this paper indicates that the accuracy of a silicon piezoresistive pressure sensor is mainly affected by thermal drift, and varies nonlinearly with the temperature. Here, a smart temperature compensation system to reduce its effect on accuracy is proposed. Firstly, an effective conditioning circuit for signal processing and data acquisition is designed. The hardware to implement the system is fabricated. Then, a program is developed on LabVIEW which incorporates an extreme learning machine (ELM) as the calibration algorithm for the pressure drift. The implementation of the algorithm was ported to a micro-control unit (MCU) after calibration in the computer. Practical pressure measurement experiments are carried out to verify the system's performance. The temperature compensation is solved in the interval from -40 to 85 C. The compensated sensor is aimed at providing pressure measurement in oil-gas pipelines. Compared with other algorithms, ELM acquires higher accuracy and is more suitable for batch compensation because of its higher generalization and faster learning speed. The accuracy, linearity, zero temperature coefficient and sensitivity temperature coefficient of the tested sensor are 2.57% FS, 2.49% FS, 8.1 10(-5)/C and 29.5 10(-5)/C before compensation, and are improved to 0.13%FS, 0.15%FS, 1.17 10(-5)/C and 2.1 10(-5)/C respectively, after compensation. The experimental results demonstrate that the proposed system is valid for the temperature compensation and high accuracy requirement of the sensor. PMID:25006998

Zhou, Guanwu; Zhao, Yulong; Guo, Fangfang; Xu, Wenju

2014-01-01

283

A Smart High Accuracy Silicon Piezoresistive Pressure Sensor Temperature Compensation System  

PubMed Central

Theoretical analysis in this paper indicates that the accuracy of a silicon piezoresistive pressure sensor is mainly affected by thermal drift, and varies nonlinearly with the temperature. Here, a smart temperature compensation system to reduce its effect on accuracy is proposed. Firstly, an effective conditioning circuit for signal processing and data acquisition is designed. The hardware to implement the system is fabricated. Then, a program is developed on LabVIEW which incorporates an extreme learning machine (ELM) as the calibration algorithm for the pressure drift. The implementation of the algorithm was ported to a micro-control unit (MCU) after calibration in the computer. Practical pressure measurement experiments are carried out to verify the system's performance. The temperature compensation is solved in the interval from ?40 to 85 C. The compensated sensor is aimed at providing pressure measurement in oil-gas pipelines. Compared with other algorithms, ELM acquires higher accuracy and is more suitable for batch compensation because of its higher generalization and faster learning speed. The accuracy, linearity, zero temperature coefficient and sensitivity temperature coefficient of the tested sensor are 2.57% FS, 2.49% FS, 8.1 10?5/C and 29.5 10?5/C before compensation, and are improved to 0.13%FS, 0.15%FS, 1.17 10?5/C and 2.1 10?5/C respectively, after compensation. The experimental results demonstrate that the proposed system is valid for the temperature compensation and high accuracy requirement of the sensor. PMID:25006998

Zhou, Guanwu; Zhao, Yulong; Guo, Fangfang; Xu, Wenju

2014-01-01

284

List mode reconstruction for PET with motion compensation: A simulation study  

SciTech Connect

Motion artifacts can be a significant factor that limits the image quality in high-resolution PET. Surveillance systems have been developed to track the movements of the subject during a scan. Development of reconstruction algorithms that are able to compensate for the subject motion will increase the potential of PET. In this paper we present a list mode likelihood reconstruction algorithm with the ability of motion compensation. The subject motion is explicitly modeled in the likelihood function. The detections of each detector pair are modeled as a Poisson process with time-varying rate function. The proposed method has several advantages over the existing methods. It uses all detected events and does not introduce any interpolation error. Computer simulations show that the proposed method can compensate simulated subject movements and that the reconstructed images have no visible motion artifacts.

Qi, Jinyi; Huesman, Ronald H.

2002-07-01

285

List mode reconstruction for PET with motion compensation: A simulation study  

SciTech Connect

Motion artifacts can be a significant factor that limits the image quality in high-resolution PET. Surveillance systems have been developed to track the movements of the subject during a scan. Development of reconstruction algorithms that are able to compensate for the subject motion will increase the potential of PET. In this paper we present a list mode likelihood reconstruction algorithm with the ability of motion compensation. The subject moti is explicitly modeled in the likelihood function. The detections of each detector pair are modeled as a Poisson process with time vary ingrate function. The proposed method has several advantages over the existing methods. It uses all detected events and does not introduce any interpolation error. Computer simulations show that the proposed method can compensate simulated subject movements and that the reconstructed images have no visible motion artifacts.

Qi, Jinyi; Huesman, Ronald H.

2002-07-03

286

Motion compensated tomography reconstruction of coronary arteries in rotational angiography  

PubMed Central

This paper deals with the 3-D reconstruction of the coronary tree from a rotational X-ray projection sequence. It describes the following three stages: the reconstruction of the 3-D coronary tree at different phases of the cardiac cycle, the motion estimation, and the motion-compensated tomographic reconstruction of the 3-D coronary tree at one given phase using all the available projections. Our method is tested on a series of simulated images computed from the projection of a segmented dynamic volume sequence acquired in multislice computed tomography imaging. Performances are comparable to those obtained by reconstruction of a statical coronary tree using an algebraic reconstruction technique algorithm. PMID:19272935

Bousse, Alexandre; Zhou, Jian; Yang, Guanyu; Bellanger, Jean-Jacques; Toumoulin, Christine

2009-01-01

287

LPV Antiwindup Compensation for Enhanced Flight Control Performance  

NASA Technical Reports Server (NTRS)

In this paper, we propose a saturation control scheme for linear parameter-varying (LPV) systems from an antiwindup control perspective. The proposed control approach is advantageous because it can be thought of as an augmented control algorithm from the existing control system. Moreover, the synthesis condition for an antiwindup compensator is formulated as a linear matrix inequality (LMI) optimization problem and can be solved efficiently. We have applied the LPV antiwindup controller to an F-16 longitudinal autopilot control system design to enhance aircraft safety and improve flight quality in a high angle of attack region.

Lu, Bei; Wu, Fen; Kim, Sung-Wan

2003-01-01

288

VALIDATION OF TEMPERATURE COMPENSATION TECHNIQUES FOR IMPACT DAMAGE DETECTION AND LOCALIZATION USING ULTRASONIC  

E-print Network

USING ULTRASONIC SPARSE ARRAYS Michael Scheerer1 , Daniel Lager2 1 Aerospace & Advanced Composites Gmb measurement ­ was implemented in virtual beam forming algorithm used to visualize the ultrasonic image Ultrasonic Waves, Temperature Compensation, Composite Honeycomb Panels, Impact Damage INTRODUCTION Guided

Boyer, Edmond

289

A compensated vector control scheme of a synchronous reluctance motor including saturation and iron losses  

Microsoft Academic Search

A compensated vector control algorithm for a synchronous reluctance motor (SRM) including saturation and iron losses is presented. It is shown that the current components that directly govern the torque production have been very well regulated by the proposed control scheme. The computer simulation and experimental results indicate a substantial improvement of torque performance for the vector-controlled SRM

L. Xu; J. Yao

1992-01-01

290

Noise Driven Short-Time Phase Spectrum Compensation Procedure for Speech Enhancement  

E-print Network

Noise Driven Short-Time Phase Spectrum Compensation Procedure for Speech Enhancement Anthony P.lyons, k.paliwal}@griffith.edu.au Abstract Typical speech enhancement algorithms operate on the short- time approach to speech enhancement has been proposed where the noisy mag- nitude spectrum is recombined

291

RATE-DISTORTION BOUNDS FOR MOTION COMPENSATED RATE SCALABLE VIDEO CODERS  

Microsoft Academic Search

In this paper, we derive and evahiate theoretical rate- distortion performance bounds for scalable video compres- sion algorithms which use a single motion-compensated prediction (MCP) loop. These bounds are derived using ratedistortion theory based on an optirnuni mean-square error (MSE) quantizer. By specifying translatory motion and using an approximation of the predictcd error frame power spectral density, it is possible

Gregory W. Cool; J. Prudes-Nebott; Valencia Valencia

292

A Statistical Approach for Intensity Loss Compensation of Confocal Microscopy Images  

Microsoft Academic Search

In this paper a probabilistic technique for compensation of inten- sity loss in the confocal microscopy images is presented. Confo- cal microscopy images are modeled as a mixture of two Gaussians, one representing the background and another corresponding to the foreground. Images are segmented into foreground and background by applying Expectation Maximization (EM) algorithm to the mix- ture. Final intensity

Sowmya Gopinath; Ninad Thakoor; Jean Gao; Kate Luby-phelps

2007-01-01

293

Artificial satellites attitude adaptive estimation using Kalman filter with dynamic model compensation  

Microsoft Academic Search

An optimal estimation algorithm is developed with the capability of real time applications under unfavorable conditions (acquisition phase, e.g.), when external torques are not completely known and have significant effect on attitude dynamics. To do so a procedure is used which combines extended Kalman filter with dynamical model compensation and adaptive state noise estimation techniques. The external torques (gravitational, magnetic,

A. R. Neto; R. V. D. F. Lopes; R. N. Depaiva

1982-01-01

294

Compensation and Working Conditions Online  

NSDL National Science Digital Library

The US Bureau of Labor Statistics (BLS) has recently begun to provide this publication, a complement to its print counterpart, via the web. The online version mirrors the articles, briefs, and tables of the print version. Some articles are available in text, and some only in Adobe Acrobat [.pdf] format. Each issue is accompanied by relevant BLS tables such as the Employment Cost Index, Major Work Stoppages, and the Occupational Compensation Survey. The present issue (Vol. 3, No. 1) contains articles on professional sports team salary caps, fatal work injuries for 1996, and scientists' earnings.

295

Spatial frequency domain model for adaptive optics compensation of segmented mirror misalignments and figure errors  

Microsoft Academic Search

In addition to their essential function of providing atmospheric turbulence compensation, astronomical Adaptive Optical (AO) systems also supplement the role of active optics (aO) by providing some additional correction of the wavefront aberrations introduced by mirror mounting, alignment, thermal distortion and\\/or fabrication errors. This feature is particularly desirable for segmented mirror telescopes such as the Thirty Meter Telescope (TMT), but

Brent L. Ellerbroek

2006-01-01

296

CEO compensation and hospital financial performance.  

PubMed

Growing interest in pay-for-performance and the level of chief executive officers' (CEOs') pay raises questions about the link between performance and compensation in the health sector. This study compares the compensation of nonprofit hospital CEOs in Ontario, Canada to the three longest reported and most used measures of hospital financial performance. Our sample consisted of 132 CEOs from 92 hospitals between 1999 and 2006. Unbalanced panel data were analyzed using fixed effects regression. Results suggest that CEO compensation was largely unrelated to hospital financial performance. Inflation-adjusted salaries appeared to increase over time independent of hospital performance, and hospital size was positively correlated with CEO compensation. The apparent upward trend in salary despite some declines in financial performance challenges the fundamental assumption underlying this article, that is, financial performance is likely linked to CEO compensation in Ontario. Further research is needed to understand long-term performance related to compensation incentives. PMID:19605619

Reiter, Kristin L; Sandoval, Guillermo A; Brown, Adalsteinn D; Pink, George H

2009-12-01

297

CEO Compensation and Hospital Financial Performance  

PubMed Central

Growing interest in pay-for-performance and the level of CEO pay raises questions about the link between performance and compensation in the health sector. This study compares the compensation of non-profit hospital Chief Executive Officers (CEOs) in Ontario, Canada to the three longest reported and most used measures of hospital financial performance. Our sample consisted of 132 CEOs from 92 hospitals between 1999 and 2006. Unbalanced panel data were analyzed using fixed effects regression. Results suggest that CEO compensation was largely unrelated to hospital financial performance. Inflation-adjusted salaries appeared to increase over time independent of hospital performance, and hospital size was positively correlated with CEO compensation. The apparent upward trend in salary despite some declines in financial performance challenges the fundamental assumption underlying this paper, that is, financial performance is likely linked to CEO compensation in Ontario. Further research is needed to understand long-term performance related to compensation incentives. PMID:19605619

Reiter, Kristin L.; Sandoval, Guillermo A.; Brown, Adalsteinn D.; Pink, George H.

2010-01-01

298

Pointing compensation system for spacecraft instruments  

NASA Technical Reports Server (NTRS)

A closed loop system reduces pointing errors in one or more spacecraft instruments. Associated with each instrument is a electronics package (3) for commanding motion in that instrument and a pointing control system (5) for imparting motion in that instrument in response to a command (4) from the commanding package (3). Spacecraft motion compensation logic (25) compensates for instrument pointing errors caused by instrument-motion-induced spacecraft motion. Any finite number of instruments can be so compensated, by providing each pointing control system (5) and each commanding package (3), for the instruments desired to be compensated, with a link to the spacecraft motion compensation logic (25). The spacecraft motion compensation logic (25) is an electronic manifestation of the algebraic negative of a model of the dynamics of motion of the spacecraft. An example of a suitable model, and computer-simulated results, are presented.

Plescia, Carl T. (Inventor); Gamble, Donald W. (Inventor)

1987-01-01

299

Compensation of static deformation and vibrations of antenna arrays  

NASA Astrophysics Data System (ADS)

The effect of vibrations and static deformations on aerospace platforms and their influence on the performance of radar, navigation or communication systems are currently studied in the scope of the NATO Research Task Groups SET-131. The deformations may be caused by different effects, e.g. aerodynamic loads, vehicle motion, moving parts such as rudders or turbines, or the impact of a collision. Depending on their strength and the function of the wireless system, they may have a significant impact on the system performance. Structural aspects of the platform such as mechanical or thermal stability, aerodynamics or outer appearance are of great importance. The present paper gives an overview of the scope of work of the group and on-going investigations on system performance analysis and compensation methods such as adaptive signal processing or electronic phase compensation for military key applications such as RADAR, Communication, Electronic Support Measures (ESM) or Command and Control (C2). In addition, the development of an antenna array demonstrator with active vibration compensation using piezo sensors and actuators and control algorithms will be shown, including simulated as well as experimental results.

Knott, Peter; Loecker, Claudius; Algermissen, Stephan; Sekora, Robert

2012-11-01

300

Compensation of low order aberrations with reflective beam shaping system  

NASA Astrophysics Data System (ADS)

Compensation of low order aberrations is essential for high power solid state slab laser. With the increase of output power, the peak-to-valley of wavefront distortion increase to dozens of micrometer. It's difficult to control the wavefront with deformable mirrors which always has limited stroke(<20?m). In this paper, a reflective beam shaping system is designed to shaping the beam spot from rectangular to squarer. The beam shaping system consists of two x-oriented cylindrical mirrors and two y-oriented cylindrical mirrors. Simulations of PID control algorithm for actively compensating of low-order aberrations with reflective beam shaping system are presented. It shows that different combinations of defocus, 0o astigmatism and 45 astigmatism, which is the main contributor of beam aberrations in slab laser, can be well compensated by adjustment of distance and rotation angle of mirrors. And the convergence is fast when the control error signal is set to a suitable combination of low order Zernike coefficients. For beam with wave aberrations (PtV=82.6?, RMS=18.2?, Z4=23.6, Z5=7.1, Z6=19.6), the adjustment of distance between mirrors is below 100mm, and the rotation angle about z-axis is below 2 degree. The wavefront aberrations are decreased to a low level (PV=0.16?, RMS=0.04?) which can be easily corrected later with DM.

Liu, Wenguang; Zhou, Qiong; Gu, Dianyu; Jiang, Zongfu

2014-05-01

301

Enhanced adaptive loop filter for motion compensated frame.  

PubMed

We propose an adaptive loop filter to remove the redundancy between current and motion compensated frames so that the residual signal is minimized, thus coding efficiency increases. The loop filter coefficients and offset are optimized for each frame or a set of blocks to minimize the total energy of the residual signal resulting from motion estimation and compensation. The optimized loop filter with offset is applied for the set of blocks where the filtering process gives coding gain based upon rate-distortion cost. The proposed loop filter is used for the motion compensated frame whereas the conventional adaptive interpolation filter (AIF) is applied to the reference frames to interpolate the subpixel values. Another conventional scheme adaptive loop filter (ALF), is used after deblocking filtering to enhance quality of reconstructed frames, not to minimize energy of residual signal. The proposed loop filter can be used in combination with the AIF and ALF. Experimental results show that proposed algorithm provides the averaged bit reduction of 8% compared to conventional H.264/AVC scheme. When the proposed scheme is combined with AIF and ALF, the coding gain increases even further. PMID:21592920

Yoo, Young-Joe; Seo, Chan-Won; Han, Jong-Ki; Nguyen, Truong Q

2011-08-01

302

A temperature compensated 1 GHz STW oscillator  

Microsoft Academic Search

An improved temperature compensation technique, applied to a 1-GHz surface transverse wave (STW) oscillator using 36 rotated Y-cut quartz, is described. The parabolic temperature dependence is roughly compensated for by an analog circuit. A fine compensation is performed by simple digital circuitry keeping the total instability within 1.4 p.p.m. over the temperature range of (-45. . .+75)C. The key for

M. A. Taslakov; I. D. Avramov

1991-01-01

303

Determination and compensation of aberrations using SLMs  

NASA Astrophysics Data System (ADS)

The performance of an optical system depends on its aberrations. One way to reduce aberrations is a careful a priori optimization of the lens design. For a given system the introduction of a compensation hologram can lead to a perfect system. For this purpose, however, the exact lens data needs to be known or the compensation data has to be measured. In this paper, we present a novel method for the measurement and the application of compensation holograms using spatial light modulators.

Liesener, J.; Reicherter, M.; Tiziani, H. J.

2004-03-01

304

Square-Wave Analysis of Compensated Amplifiers  

Microsoft Academic Search

A complete analysis of a single-stage compensated video-frequency amplifier is presented. In this amplifier high-frequency compensation is obtained by the use of a shunt peaking coil in series with the plate load resistance, and low-frequency compensation is obtained by using a resistance-capacitance network in series with the plate load resistance. Both square-wave and sine-wave input voltages to the amplifier are

P. M. Seal

1949-01-01

305

Multiexposure and multifocus image fusion with multidimensional camera shake compensation  

NASA Astrophysics Data System (ADS)

Multiexposure image fusion algorithms are used for enhancing the perceptual quality of an image captured by sensors of limited dynamic range. This is achieved by rendering a single scene based on multiple images captured at different exposure times. Similarly, multifocus image fusion is used when the limited depth of focus on a selected focus setting of a camera results in parts of an image being out of focus. The solution adopted is to fuse together a number of multifocus images to create an image that is focused throughout. A single algorithm that can perform both multifocus and multiexposure image fusion is proposed. This algorithm is a new approach in which a set of unregistered multiexposure/focus images is first registered before being fused to compensate for the possible presence of camera shake. The registration of images is done via identifying matching key-points in constituent images using scale invariant feature transforms. The random sample consensus algorithm is used to identify inliers of SIFT key-points removing outliers that can cause errors in the registration process. Finally, the coherent point drift algorithm is used to register the images, preparing them to be fused in the subsequent fusion stage. For the fusion of images, a new approach based on an improved version of a wavelet-based contourlet transform is used. The experimental results and the detailed analysis presented prove that the proposed algorithm is capable of producing high-dynamic range (HDR) or multifocus images by registering and fusing a set of multiexposure or multifocus images taken in the presence of camera shake. Further, comparison of the performance of the proposed algorithm with a number of state-of-the art algorithms and commercial software packages is provided. In particular, our literature review has revealed that this is one of the first attempts where the compensation of camera shake, a very likely practical problem that can result in HDR image capture using handheld devices, has been addressed as a part of a multifocus and multiexposure image enhancement system.

Gomez, Alexis Lluis; Saravi, Sara; Edirisinghe, Eran A.

2013-10-01

306

Log amplifier with pole-zero compensation  

DOEpatents

A logarithmic amplifier circuit provides pole-zero compensation for improved stability and response time over 6-8 decades of input signal frequency. The amplifier circuit includes a first operational amplifier with a first feedback loop which includes a second, inverting operational amplifier in a second feedback loop. The compensated output signal is provided by the second operational amplifier with the log elements, i.e., resistors, and the compensating capacitors in each of the feedback loops having equal values so that each break point or pole is offset by a compensating break point or zero.

Brookshier, William (Downers Grove, IL)

1987-01-01

307

A new controlling system for the solar tower telescope of IZMIRAN: II. A solar image motion compensator  

Microsoft Academic Search

A solar image motion compensator for the solar tower telescope is described. Two mutually perpendicular CCD linear arrays\\u000a are used as photodetectors. An algorithm for forecasting the system behavior is used for generation of correction signals.\\u000a Analyzing the solar image motion data obtained using the compensator and without it has shown that, thanks to its use, the\\u000a total image motion

I. E. Kozhevatov; E. A. Rudenchik; N. P. Cheragin; B. A. Ioshpa; E. Kh. Kulikova; E. G. Bezrukova

2000-01-01

308

38 CFR 21.3023 - Nonduplication; pension, compensation, and dependency and indemnity compensation.  

Code of Federal Regulations, 2010 CFR

38 Pensions, Bonuses, and Veterans' Relief 2...2010-07-01 false Nonduplication; pension, compensation, and dependency and indemnity...compensation. 21.3023 Section 21.3023 Pensions, Bonuses, and Veterans' Relief...

2010-07-01

309

Optimal packaging of dispersion-compensating fibers for matched nonlinear compensation and reduced optical noise.  

PubMed

A method of packaging dispersion-compensating fibers (DCFs) is discussed that achieves optimal nonlinearity compensation and a good signal-to-noise ratio simultaneously. An optimally packaged dispersion-compensating module (DCM) may consist of portions of DCFs with higher and lower loss coefficients. Such optimized DCMs may be paired with transmission fibers to form scaled translation-symmetric lines that could effectively compensate for signal distortions due to dispersion and nonlinearity, with or without optical phase conjugation. PMID:16196322

Wei, Haiqing; Plant, David V

2005-09-15

310

Atmosphere control  

NASA Technical Reports Server (NTRS)

Atmospheric control studies emphasized the carbon dioxide problem. Trace contaminants are removed by solid adsorbents and by catalytic oxidation. Humidity control and storage systems for atmospheric constituents are briefly summarized.

Jones, W. L.; Ingelfinger, A. L.

1973-01-01

311

Compensating for synaptic loss in Alzheimer's disease.  

PubMed

Confirming that synaptic loss is directly related to cognitive deficit in Alzheimer's disease (AD) has been the focus of many studies. Compensation mechanisms counteract synaptic loss and prevent the catastrophic amnesia induced by synaptic loss via maintaining the activity levels of neural circuits. Here we investigate the interplay between various synaptic degeneration and compensation mechanisms, and abnormal cortical oscillations based on a large-scale network model consisting of 100,000 neurons exhibiting several cortical firing patterns, 8.5 million synapses, short-term plasticity, axonal delays and receptor kinetics. The structure of the model is inspired by the anatomy of the cerebral cortex. The results of the modelling study suggest that cortical oscillations respond differently to compensation mechanisms. Local compensation preserves the baseline activity of theta (5-7 Hz) and alpha (8-12 Hz) oscillations whereas delta (1-4 Hz) and beta (13-30 Hz) oscillations are maintained via global compensation. Applying compensation mechanisms independently shows greater effects than combining both compensation mechanisms in one model and applying them in parallel. Consequently, it can be speculated that enhancing local compensation might recover the neural processes and cognitive functions that are associated with theta and alpha oscillations whereas inducing global compensation might contribute to the repair of neural (cognitive) processes which are associated with delta and beta band activity. Compensation mechanisms may vary across cortical regions and the activation of inappropriate compensation mechanism in a particular region may fail to recover network dynamics and/or induce secondary pathological changes in the network. PMID:23728490

Abuhassan, Kamal; Coyle, Damien; Belatreche, Ammar; Maguire, Liam

2014-02-01

312

Optimized Reactive Power Compensation Using Fuzzy Logic Controller  

NASA Astrophysics Data System (ADS)

Reactive power flow in a long transmission line plays a vital role in power transfer capability and voltage stability in power system. Traditionally, shunt connected compensators are used to control reactive power in long transmission line. Thyristor controlled reactor is used to control reactive power under lightly loaded condition. By controlling firing angle of thyristor, it is possible to control reactive power in the transmission lines. However, thyristor controlled reactor will inject harmonic current into the system. An attempt to reduce reactive power injection will increase harmonic distortion in the line current and vice versa. Thus, there is a trade-off between reactive power injection and harmonics in current. By optimally controlling the reactive power injection, harmonics in current can be brought within the specified limit. In this paper, a Fuzzy Logic Controller is implemented to obtain optimal control of reactive power of the compensator to maintain voltage and harmonic in current within the limits. An algorithm which optimizes the firing angle in each fuzzy subset by calculating the rank of feasible firing angles is proposed for the construction of rules in Fuzzy Logic Controller. The novelty of the algorithm is that it uses a simple error formula for the calculation of the rank of the feasible firing angles in each fuzzy subset.

George, S.; Mini, K. N.; Supriya, K.

2015-03-01

313

Decision-aided sampling frequency offset compensation for reduced-guard-interval coherent optical OFDM systems.  

PubMed

We propose a decision-aided algorithm to compensate the sampling frequency offset (SFO) between the transmitter and receiver for reduced-guard-interval (RGI) coherent optical (CO) OFDM systems. In this paper, we first derive the cyclic prefix (CP) requirement for preventing OFDM symbols from SFO induced inter-symbol interference (ISI). Then we propose a new decision-aided SFO compensation (DA-SFOC) algorithm, which shows a high SFO tolerance and reduces the CP requirement. The performance of DA-SFOC is numerically investigated for various situations. Finally, the proposed algorithm is verified in a single channel 28 Gbaud polarization division multiplexing (PDM) RGI CO-OFDM experiment with QPSK, 8 QAM and 16 QAM modulation formats, respectively. Both numerical and experimental results show that the proposed DA-SFOC method is highly robust against the standard SFO in optical fiber transmission. PMID:25401902

Wang, Wei; Zhuge, Qunbi; Morsy-Osman, Mohamed; Gao, Yuliang; Xu, Xian; Chagnon, Mathieu; Qiu, Meng; Hoang, Minh Thang; Zhang, Fangyuan; Li, Rui; Plant, David V

2014-11-01

314

Self-compensating solenoid valve  

NASA Technical Reports Server (NTRS)

A solenoid valve is described in which both an inlet and an outlet of the valve are sealed when the valve is closed. This double seal compensates for leakage at either the inlet or the outlet by making the other seal more effective in response to the leakage and allows the reversal of the flow direction by simply switching the inlet and outlet connections. The solenoid valve has a valve chamber within the valve body. Inlet and outlet tubes extend through a plate into the chamber. A movable core in the chamber extends into the solenoid coil. The distal end of the core has a silicone rubber plug. Other than when the solenoid is energized, the compressed spring biases the core downward so that the surface of the plug is in sealing engagement with the ends of the tubes. A leak at either end increases the pressure in the chamber, resulting in increased sealing force of the plug.

Woeller, Fritz H. (inventor); Matsumoto, Yutaka (inventor)

1987-01-01

315

SIS junction reactance complete compensation  

SciTech Connect

SIS junction geometrical capacitance together with out of phase current I{sub kk} impedance component forms sufficient junction reactance X{sub SIS} = ({omega}C + B{sub Q}){sup {minus}1}. This paper suggests the way to resonate out both {omega}C and B{sub Q} by using additional identical SIS junction connected to the first through a long line impedance inverter and RF + DC biased symmetrically to the first. Pumped IV curves without quantum reactance and frequency impedance patterns of the system were calculated. Calculations demonstrated the presence of high and even negative induced dynamic resistance regions at high order quasiparticle steps for the case of SIS junction reactance complete compensation. The suggested method may be used in SIS mixers and detectors for a better RF matching.

Beletsky, V.Y.; Tarasov, M.A. (Inst. of Radio Engineering and Electronics, USSR Academy of Sciences, Marx Avenue 18 (SU))

1991-03-01

316

Interactive atmosphere  

NSDL National Science Digital Library

Where is ozone located in the atmosphere? This informational activity, part of an interactive laboratory series for grades 8-12, explores the changes in ozone concentration with altitude. Students are introduced to layers of the atmosphere and the amount of ozone found at each layer of the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. The activity also discusses why the addition of ozone to the atmosphere at different levels determines the temperatures of those levels. Students can move up and down to different layers of the atmosphere. A temperature scale is shown that runs from the surface of the Earth to the outer most reaches of the atmosphere. Copyright 2005 Eisenhower National Clearinghouse

University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

2003-01-01

317

Homotopy Algorithm for Fixed Order Mixed H2/H(infinity) Design  

NASA Technical Reports Server (NTRS)

Recent developments in the field of robust multivariable control have merged the theories of H-infinity and H-2 control. This mixed H-2/H-infinity compensator formulation allows design for nominal performance by H-2 norm minimization while guaranteeing robust stability to unstructured uncertainties by constraining the H-infinity norm. A key difficulty associated with mixed H-2/H-infinity compensation is compensator synthesis. A homotopy algorithm is presented for synthesis of fixed order mixed H-2/H-infinity compensators. Numerical results are presented for a four disk flexible structure to evaluate the efficiency of the algorithm.

Whorton, Mark; Buschek, Harald; Calise, Anthony J.

1996-01-01

318

Idol worship as compensation for parental absence  

Microsoft Academic Search

Idol worship refers to psychological identification with and emotional attachment to an idol figure, who is most likely to be a celebrity for young people nowadays. Fragmentary findings in previous research on adolescent idol worship suggest that it may represent compensation for the worshipper's deficits, such as those in parental resources. To illuminate this compensation perspective, the study surveyed 401

Chau-kiu Cheung; Xiao Dong Yue

2012-01-01

319

12 CFR 620.31 - Compensation committees.  

Code of Federal Regulations, 2010 CFR

...years. (a) Composition. Each compensation committee must consist of at least...of the institution's board of directors. Every member must be free from...would interfere with the exercise of independent judgment as a committee member. (b) Duties. Each compensation committee must report only to the board of directors. In its capacity as a...

2010-01-01

320

Managerial compensation and the debt placement decision  

Microsoft Academic Search

Extant research argues that borrowing from financial intermediaries subjects managers to external monitoring. However, given managers' flexibility in choosing the type of debt financing, why would managers submit themselves to external monitoring? Recent theory points to the role of managerial incentive compensation. Specifically, it is argued that managers will borrow from financial intermediaries if their compensation is tied to firm

Susan M. Albring; Inder K. Khurana; Ali Nejadmalayeri; Raynolde Pereira

2011-01-01

321

Reinventing Teacher Compensation Systems. CPRE Finance Briefs.  

ERIC Educational Resources Information Center

Other organizations in the United States have successfully implemented new compensation structures. This publication argues that it is time for education to join these successful efforts and revise teacher-pay systems. The brief provides a short history of changes in teacher compensation over the last century and a discussion of key organizational

Kelley, Carolyn; Odden, Allan

322

Executive Compensation as an Agency Problem  

Microsoft Academic Search

This paper provides an overview of the main theoretical elements and empirical underpinnings of a managerial power' approach to executive compensation. Under this approach, the design of executive compensation is viewed not only as an instrument for addressing the agency problem between managers and shareholders but also as part of the agency problem itself. Boards of publicly traded companies with

Lucian Arye Bebchuk; Jesse M. Fried

2003-01-01

323

Higher Education Compensation Systems of the Future.  

ERIC Educational Resources Information Center

New methods of structuring college faculty compensation systems are needed to involve, motivate, reward, and recognize individual and group behaviors. Compensation systems of the future should support the institution's core values, recognize that success results from interdependent relationships and not only individual accomplishments, and include

Foldesi, Robert S.

1996-01-01

324

Compensating linkage for main rotor control  

NASA Technical Reports Server (NTRS)

A compensating linkage for the rotor control system on rotary wing aircraft is described. The main rotor and transmission are isolated from the airframe structure by clastic suspension. The compensating linkage prevents unwanted signal inputs to the rotor control system caused by relative motion of the airframe structure and the main rotor and transmission.

Jeffery, P. A. E.; Huber, R. F. (inventors)

1981-01-01

325

Steering compensation for high-performance motorcycles  

Microsoft Academic Search

This paper introduces the idea of using a mechanical steering compensator to influence the dynamic behaviour of a high-performance motorcycle. The compensator is seen as a possible replacement for a conventional steering damper, and comprises a network of a spring, a damper and a less familiar component called the inerter. The inerter was recently introduced to allow the synthesis of

Simos Evangelou; David J. N. Limebeer; Robin S. Sharp; Malcolm C. Smith

2004-01-01

326

Compensation Basics For Managers and Supervisors  

E-print Network

;4 Truths About Compensation Truth #2: The best employees are not attracted, motivated and retained solely About Compensation Truth # 4: An employee's knowledge of base pay correlates highly with pay satisfaction which is highly associated with job satisfaction. (Source: Knowledge of Pay Study (2000) conducted

Weaver, Harold A. "Hal"

327

Clipping Noise Compensation for OFDMA Systems  

Microsoft Academic Search

This paper presents an efficient low-complexity clipping noise compensation scheme for PAR reduced orthogonal frequency division multiple access (OFDMA) systems. Conventional clipping noise compensation schemes proposed for OFDM systems are decision directed schemes which use demodulated data symbols. Thus these schemes fail to deliver expected performance in OFDMA systems where multiple users share a single OFDM symbol and a specific

Ying Chen; Jian Zhang; D. Jayalath

2009-01-01

328

Executive compensation and internal capital market efficiency  

Microsoft Academic Search

We document that chief executive officer (CEO) incentive compensation plays an important role in determining internal capital market (ICM) allocation efficiency. Our results suggest that CEO equity-based compensation can be effective in ameliorating inefficiencies in internal capital allocation decisions. We find that while stock grants play an important role in motivating CEOs to make more efficient internal capital allocation decisions,

Sudip Datta; Ranjan D'Mello; Mai Iskandar-Datta

2009-01-01

329

Nonsalary Compensation for Employees of Independent Schools.  

ERIC Educational Resources Information Center

A guide, intended to help independent schools attract and retain competent people through appropriate compensation packages, provides the basis for a review of a school's current general benefits program. It also contains suggestions for improving compensation packages by offering a wider range of tax-favored nonsalary benefits without necessarily

Miller, Ned A.

330

Tilt/Integral/Derivative Compensators For Controllers  

NASA Technical Reports Server (NTRS)

Tilt/integral/derivative (TID) compensators for tunable feedback control systems offer advantages over proportional/integral/derivative compensators. Designed and adjusted more easily, and made to reject disturbances more strongly and less sensitive to variations in parameters of controlled system.

Lurie, Boris J.

1995-01-01

331

Searching for Reason in Presidential Compensation.  

ERIC Educational Resources Information Center

Two developments require college governing boards and presidents to focus on executive compensation policies: the New York Regents' removal of the Adelphi University (New York) board over presidential salary and benefits, and federal legislation empowering the Internal Revenue Service to impose sanctions for excessive compensation in tax-exempt

Ingram, Richard T.

1997-01-01

332

The Older Worker's Stake in Workers' Compensation  

ERIC Educational Resources Information Center

State Workers' Compensation programs can add another barrier for older workers to surmount at the hiring gate. State programs do not furnish adequate or equitable protection, and the National Commission on State Workmen's Compensation Laws has made recommendations to improve coverage; new standards must be met by July, 1975. (Author)

Berkowitz, Monroe

1975-01-01

333

Compensation of unmodeled puma manipulator dynamics  

Microsoft Academic Search

Forces unmodeled by Lagrange-Euler dynamics restrict the trajectory tracking accuracy of dynamics based PUMA manipulator control laws. The ability of unmodeled force compensation techniques to eliminate those restrictions, enabling dynamics based PUMA controllers to accurately track a high speed trajectory, has been identified. Implementation of nonlinear velocity dependent friction compensation in the feedforward loop significantly improves controller efficacy. A combination

M. B. Leahy; G. N. Saridis

1987-01-01

334

Mutual coupling compensation in small array antennas  

Microsoft Academic Search

A technique to compensate for mutual coupling in a small array is developed and experimentally verified. Mathematically, the compensation consists of a matrix multiplication performed on the received-signal vector. This, in effect, restores the signals as received by the isolated elements in the absence of mutual coupling. This technique is most practical for digital beamforming antennas where the matrix operation

Hans Steyskal; J. S. Herd

1990-01-01

335

Atmospheric gases  

NSDL National Science Digital Library

Which gases make up the atmosphere? This activity page, part of an interactive laboratory series for grades 8-12, introduces students to the gaseous components of the atmosphere. Students explore the main gases of the atmosphere using a pop-up pie chart. Descriptions of the gases and their percentages in the atmosphere are provided. Students read about water vapor in the atmosphere, and an animation shows a simplified process of precipitation. A pop-up window explains the effects of dust on the atmosphere, and a photograph shows how large amounts of dust in the atmosphere create the reds and oranges displayed in sunsets. Finally, ozone is introduced to students as a necessary component of human life on Earth. Copyright 2005 Eisenhower National Clearinghouse

University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

2003-01-01

336

Compensation of the Effect of a Detector Solenoid on the Beam Size in the ILC  

SciTech Connect

In the International Linear Collider (ILC) [1] the colliding beams must be focused to the nanometer size in order to reach the desired luminosity. The method of Weak Antisolenoid is used for the compensation of the effect of the Detector Solenoid on the beam size [2], [3]. The studies of this method require the computer simulation of the charged particle's kinematics in the arbitrarily distributed solenoidal, dipole, quadrupole and higher multipole fields. We suggest the mathematical algorithm that allows to optimize parameters of antisolenoid for different configurations of Final Focus magnets and to compensate parasitic effects of the Detector Solenoid on the beam.

Seletskiy, S.; /SLAC

2007-07-06

337

Analysis and compensation of an aircraft simulator control loading system with compliant linkage. [using hydraulic equipment  

NASA Technical Reports Server (NTRS)

A hydraulic control loading system for aircraft simulation was analyzed to find the causes of undesirable low frequency oscillations and loading effects in the output. The hypothesis of mechanical compliance in the control linkage was substantiated by comparing the behavior of a mathematical model of the system with previously obtained experimental data. A compensation scheme based on the minimum integral of the squared difference between desired and actual output was shown to be effective in reducing the undesirable output effects. The structure of the proposed compensation was computed by use of a dynamic programing algorithm and a linear state space model of the fixed elements in the system.

Johnson, P. R.; Bardusch, R. E.

1974-01-01

338

A New Technique for Compensating Joint Limits in a Robot Manipulator  

NASA Technical Reports Server (NTRS)

A new robust, optimal, adaptive technique for compensating rate and position limits in the joints of a six degree-of-freedom elbow manipulator is presented. In this new algorithm, the unmet demand as a result of actuator saturation is redistributed among the remaining unsaturated joints. The scheme is used to compensate for inadequate path planning, problems such as joint limiting, joint freezing, or even obstacle avoidance, where a desired position and orientation are not attainable due to an unrealizable joint command. Once a joint encounters a limit, supplemental commands are sent to other joints to best track, according to a selected criterion, the desired trajectory.

Litt, Jonathan; Hickman, Andre; Guo, Ten-Huei

1996-01-01

339

Dosage Compensation of the Sex Chromosomes  

PubMed Central

Differentiated sex chromosomes evolved because of suppressed recombination once sex became genetically controlled. In XX/XY and ZZ/ZW systems, the heterogametic sex became partially aneuploid after degeneration of the Y or W. Often, aneuploidy causes abnormal levels of gene expression throughout the entire genome. Dosage compensation mechanisms evolved to restore balanced expression of the genome. These mechanisms include upregulation of the heterogametic chromosome as well as repression in the homogametic sex. Remarkably, strategies for dosage compensation differ between species. In organisms where more is known about molecular mechanisms of dosage compensation, specific protein complexes containing noncoding RNAs are targeted to the X chromosome. In addition, the dosage-regulated chromosome often occupies a specific nuclear compartment. Some genes escape dosage compensation, potentially resulting in sex-specific differences in gene expression. This review focuses on dosage compensation in mammals, with comparisons to fruit flies, nematodes, and birds. PMID:22974302

Disteche, Christine M.

2013-01-01

340

The National Vaccine Injury Compensation Program.  

PubMed

The National Childhood Vaccine Injury Act of 1986 established the National Vaccine Injury Compensation Program to compensate people thought to be injured by certain vaccines. The act's goals are to ensure an adequate supply of vaccines, to stabilize vaccine costs, and to establish and maintain an accessible and efficient setting for providing compensation to people found to have been injured by certain childhood vaccines. In addition, the legislation called for the reporting of adverse events after vaccination, the creation of vaccine-information materials that detail vaccine benefits and risks, and Institute of Medicine studies of possible vaccine-related injuries and encouraged research and development of new and safer vaccines. Over its 22-year history, the National Vaccine Injury Compensation Program has been a key component in stabilizing the US vaccine market through liability protection to both vaccine companies and health care providers and by providing a forum for people, no matter what age, to seek compensation. PMID:21502255

Cook, Katherine M; Evans, Geoffrey

2011-05-01

341

20 CFR 10.401 - When and how is compensation for total disability paid?  

Code of Federal Regulations, 2010 CFR

... Section 10.401 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR ...COMPENSATION ACT, AS AMENDED Compensation and Related Benefits Compensation for Disability and Impairment...

2010-04-01

342

20 CFR 10.403 - When and how is compensation for partial disability paid?  

Code of Federal Regulations, 2010 CFR

... Section 10.403 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR ...COMPENSATION ACT, AS AMENDED Compensation and Related Benefits Compensation for Disability and Impairment...

2010-04-01

343

20 CFR 10.404 - When and how is compensation for a schedule impairment paid?  

Code of Federal Regulations, 2010 CFR

... Section 10.404 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR ...COMPENSATION ACT, AS AMENDED Compensation and Related Benefits Compensation for Disability and Impairment...

2010-04-01

344

EHW Approach to Temperature Compensation of Electronics  

NASA Technical Reports Server (NTRS)

Efforts are under way to apply the concept of evolvable hardware (EHW) to compensate for variations, with temperature, in the operational characteristics of electronic circuits. To maintain the required functionality of a given circuit at a temperature above or below the nominal operating temperature for which the circuit was originally designed, a new circuit would be evolved; moreover, to obtain the required functionality over a very wide temperature range, there would be evolved a number of circuits, each of which would satisfy the performance requirements over a small part of the total temperature range. The basic concepts and some specific implementations of EHW were described in a number of previous NASA Tech Briefs articles, namely, "Reconfigurable Arrays of Transistors for Evolvable Hardware" (NPO-20078), Vol. 25, No. 2 (February 2001), page 36; Evolutionary Automated Synthesis of Electronic Circuits (NPO- 20535), Vol. 26, No. 7 (July 2002), page 37; "Designing Reconfigurable Antennas Through Hardware Evolution" (NPO-20666), Vol. 26, No. 7 (July 2002), page 38; "Morphing in Evolutionary Synthesis of Electronic Circuits" (NPO-20837), Vol. 26, No. 8 (August 2002), page 31; "Mixtrinsic Evolutionary Synthesis of Electronic Circuits" (NPO-20773) Vol. 26, No. 8 (August 2002), page 32; and "Synthesis of Fuzzy-Logic Circuits in Evolvable Hardware" (NPO-21095) Vol. 26, No. 11 (November 2002), page 38. To recapitulate from the cited prior articles: EHW is characterized as evolutionary in a quasi-genetic sense. The essence of EHW is to construct and test a sequence of populations of circuits that function as incrementally better solutions of a given design problem through the selective, repetitive connection and/or disconnection of capacitors, transistors, amplifiers, inverters, and/or other circuit building blocks. The connection and disconnection can be effected by use of field-programmable transistor arrays (FPTAs). The evolution is guided by a search-andoptimization algorithm (in particular, a genetic algorithm) that operates in the space of possible circuits to find a circuit that exhibits an acceptably close approximation of the desired functionality. The evolved circuits can be tested by mathematical modeling (that is, computational simulation) only, tested in real hardware, or tested in combinations of computational simulation and real hardware.

Stoica, Adrian

2004-01-01

345

Predictive Compensation for Communication Outages in Networked Control Systems  

E-print Network

Predictive Compensation for Communication Outages in Networked Control Systems Erik Henriksson if the current is lost) are special cases of the more general compensation scheme presented. The predictive Henrik Sandberg Karl Henrik Johansson Abstract-- A predictive outage compensator co

Johansson, Karl Henrik

346

Position control of a servopneumatic system using fuzzy compensation  

E-print Network

The position control of a servopneumatic system in the presence of stick-slip type of friction is investigated. A cost effective, model-free fuzzy compensation scheme is proposed. The fuzzy compensation scheme compensates for the friction force...

Sathyanarayana, Sreenivas

2000-01-01

347

38 CFR 3.701 - Elections of pension or compensation.  

Code of Federal Regulations, 2010 CFR

...ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Concurrent Benefits and Elections 3...higher rate of pension or compensation becomes payable under the other law, benefits at the higher rate...

2010-07-01

348

38 CFR 3.702 - Dependency and indemnity compensation.  

Code of Federal Regulations, 2010 CFR

...DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Concurrent Benefits and Elections 3.702 Dependency and indemnity compensation. (a) Right to elect. A person who is...

2010-07-01

349

38 CFR 3.708 - Federal Employees' Compensation.  

Code of Federal Regulations, 2010 CFR

...Dependency and Indemnity Compensation Concurrent Benefits and Elections 3...Office of Workers' Compensation Programs. Benefits are not payable by...dependency and indemnity compensation or other benefits independent of...

2010-07-01

350

29 CFR 779.416 - What compensation represents commissions.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false What compensation represents commissions. 779.416...779.416 What compensation represents commissions. (a) Employment...the proportion of compensation representing commissions, all earnings...

2010-07-01

351

47 CFR 64.1310 - Payphone compensation procedures.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Payphone compensation procedures. 64.1310... FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER... 64.1310 Payphone compensation procedures. (a) Unless...consents to an alternative compensation arrangement, each...

2010-10-01

352

47 CFR 64.1300 - Payphone compensation obligation.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Payphone compensation obligation. 64.1300... FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER... 64.1300 Payphone compensation obligation. (a...by contract. (c) The compensation obligation set forth...

2010-10-01

353

16 CFR 1018.32 - Compensation and travel expenses.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Compensation and travel expenses...CONSUMER PRODUCT SAFETY COMMISSION GENERAL ADVISORY...Committees 1018.32 Compensation and travel expenses. (a) A single rate of compensation will be offered...travel. (b) The Commission shall...

2010-01-01

354

47 CFR 64.1301 - Per-payphone compensation.  

Code of Federal Regulations, 2010 CFR

... false Per-payphone compensation. 64.1301 Section 64... FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER...64.1301 Per-payphone compensation. (a) Interim access...02-292, must pay default compensation to payphone...

2010-10-01

355

47 CFR 51.711 - Symmetrical reciprocal compensation.  

Code of Federal Regulations, 2010 CFR

...Symmetrical reciprocal compensation. 51.711 Section...FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON...INTERCONNECTION Reciprocal Compensation for Transport and...Symmetrical reciprocal compensation. (a) Rates...incumbent LEC, a state commission shall establish...

2010-10-01

356

10 CFR 39.53 - Energy compensation source.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Energy compensation source. 39.53... NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION... 39.53 Energy compensation source. The licensee may use an energy compensation source...

2010-01-01

357

16 CFR 1105.7 - Limits on compensation.  

Code of Federal Regulations, 2010 CFR

...false Limits on compensation. 1105.7 Section...CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT...7 Limits on compensation. The Commission may establish a...amount of financial compensation to be made...

2010-01-01

358

18 CFR 367.29 - Compensation for use of capital.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 false Compensation for use of capital. 367...FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY ...Instructions 367.29 Compensation for use of capital. ...expenses plus reasonable compensation for necessary capital...

2010-04-01

359

47 CFR 51.703 - Reciprocal compensation obligation of LECs.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Reciprocal compensation obligation of LECs. 51... FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER...INTERCONNECTION Reciprocal Compensation for Transport and Termination... 51.703 Reciprocal compensation obligation of LECs....

2010-10-01

360

11 CFR 100.54 - Compensation for personal services.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Compensation for personal services... FEDERAL ELECTION COMMISSION GENERAL SCOPE... 100.54 Compensation for personal services...a contribution. No compensation is considered paid...time. (b) Paid on commission or piecework...

2010-01-01

361

40 CFR 1066.260 - Parasitic friction compensation evaluation.  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false Parasitic friction compensation evaluation. 1066.260...Specifications 1066.260 Parasitic friction compensation evaluation. (a) Overview...verify the accuracy of the dynamometer's friction compensation. (b) Scope and...

2012-07-01

362

40 CFR 1066.260 - Parasitic friction compensation evaluation.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Parasitic friction compensation evaluation. 1066.260...Specifications 1066.260 Parasitic friction compensation evaluation. (a) Overview...verify the accuracy of the dynamometer's friction compensation. (b) Scope and...

2013-07-01

363

40 CFR 1066.260 - Parasitic friction compensation evaluation.  

Code of Federal Regulations, 2014 CFR

... 2014-07-01 false Parasitic friction compensation evaluation. 1066.260...Specifications 1066.260 Parasitic friction compensation evaluation. (a) Overview...verify the accuracy of the dynamometer's friction compensation. (b) Scope and...

2014-07-01

364

New opportunities for secure communication networks using shaped femtosecond laser pulses inducing filamentation processes in the atmosphere  

NASA Astrophysics Data System (ADS)

The current study discusses new opportunities for secure ground to satellite communications using shaped femtosecond pulses that induce spatial hole burning in the atmosphere for efficient communications with data encoded within super-continua generated by femtosecond pulses. Refractive index variation across the different layers in the atmosphere may be modelled using assumptions that the upper strata of the atmosphere and troposphere behaving as layered composite amorphous dielectric networks composed of resistors and capacitors with different time constants across each layer. Input-output expressions of the dynamics of the networks in the frequency domain provide the transmission characteristics of the propagation medium. Femtosecond pulse shaping may be used to optimize the pulse phase-front and spectral composition across the different layers in the atmosphere. A generic procedure based on evolutionary algorithms to perform the pulse shaping is proposed. In contrast to alternative procedures that would require ab initio modelling and calculations of the propagation constant for the pulse through the atmosphere, the proposed approach is adaptive, compensating for refractive index variations along the column of air between the transmitter and receiver.

Alyami, H. M.; Becerra, V. M.; Hadjiloucas, S.

2013-11-01

365

Fast algorithm of arbitrary fractional-pixel accuracy motion estimation  

Microsoft Academic Search

The prediction error can be decreased by incorporating with high accuracy estimation and compensation, and the performance of compressed video can be improved. Two fast algorithms of fractional-pixel accuracy video motion estimation are proposed in this paper. After half-pixel accuracy motion estimation, a high accuracy motion estimation can be calculated with the intermediate results. The algorithm is based on the

Wei-Dong Wang; Qingdong Yao; Lu Yu

2002-01-01

366

Application of genetic algorithm in broadband microstrip antenna design  

Microsoft Academic Search

Genetic algorithm is utilized in the optimization of microstrip antenna with complicated structure. A broadband single-patch microstrip patch antenna is proposed. Capacitance compensated technique and E-shaped patch are combined together to expand the bandwidth of the antenna. Genetic algorithm combined with finite element software is applied to optimize the structure of the antenna. The optimization procedure is also discussed. The

Si-Yang Sun; Ying-Hua Lu; Dong-Sheng La

2009-01-01

367

Atmospheric dust  

NSDL National Science Digital Library

What is the purpose of dust in the atmosphere? On this activity page, part of an interactive laboratory series for grades 8-12, students read about the need for dust in the atmosphere as an agent for condensation. The addition of dust particles to the atmosphere by airplanes introduces students to the concept of cloud seeding and influencing the chance of rain in an area. Copyright 2005 Eisenhower National Clearinghouse

University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

2003-01-01

368

Atmospheric neutrons  

NASA Technical Reports Server (NTRS)

Contributions to fast neutron measurements in the atmosphere are outlined. The results of a calculation to determine the production, distribution and final disappearance of atmospheric neutrons over the entire spectrum are presented. An attempt is made to answer questions that relate to processes such as neutron escape from the atmosphere and C-14 production. In addition, since variations of secondary neutrons can be related to variations in the primary radiation, comment on the modulation of both radiation components is made.

Korff, S. A.; Mendell, R. B.; Merker, M.; Light, E. S.; Verschell, H. J.; Sandie, W. S.

1979-01-01

369

Error Compensation for Area Digital Sun Sensor  

PubMed Central

Compared to the error factors of the Linear Array Digital Sun Sensor (DSS), those of the Area Array DSS are complicated and methods used for error compensation are not valid or simple enough. This paper presents the main error factors of the Area Array DSS and proposes an effective method to compensate them. The procedure of error compensation of Area Array DSS includes three steps. First, the geometric error of calibration is compensated; second, the coordinate map method is used to compensate the error caused by optical refraction; third, the high order polynomial-fitting method is applied to calculate the tangent of the sun angles; finally, the arc tangent method is used to calculate the sun angles. Experimental results of the product of the High Accuracy Sun Sensor indicate that the precision is better than 0.02 during the cone field of view (CFOV) of 10, and the precision is better than 0.14 during the CFOV 10 to 64. The proposed compensation method effectively compensates the major error factors and significantly improves the measure precision of the Area APS DSS.

Li, Wen-Yang; Zhang, Gao-Fei; You, Zheng; Xing, Fei

2012-01-01

370

38 CFR 21.3024 - Nonduplication; Federal Employees' Compensation Act.  

Code of Federal Regulations, 2010 CFR

38 Pensions, Bonuses, and Veterans' Relief...Nonduplication; Federal Employees' Compensation Act. ...21.3024 Pensions, Bonuses, and Veterans' Relief...Nonduplication; Federal Employees' Compensation Act....

2010-07-01

371

Quantum Algorithms  

E-print Network

This article surveys the state of the art in quantum computer algorithms, including both black-box and non-black-box results. It is infeasible to detail all the known quantum algorithms, so a representative sample is given. This includes a summary of the early quantum algorithms, a description of the Abelian Hidden Subgroup algorithms (including Shor's factoring and discrete logarithm algorithms), quantum searching and amplitude amplification, quantum algorithms for simulating quantum mechanical systems, several non-trivial generalizations of the Abelian Hidden Subgroup Problem (and related techniques), the quantum walk paradigm for quantum algorithms, the paradigm of adiabatic algorithms, a family of ``topological'' algorithms, and algorithms for quantum tasks which cannot be done by a classical computer, followed by a discussion.

Michele Mosca

2008-08-04

372

Self Organization in Compensated Semiconductors  

NASA Astrophysics Data System (ADS)

In partially compensated semiconductor (PCS) Fermi level is pinned to donor sub-band. Due to positional randomness and almost isoenergetic hoppings, donor-spanned electronic subsystem in PCS forms fluid-like highly mobile collective state. This makes PCS playground for pattern formation, self-organization, complexity emergence, electronic neural networks, and perhaps even for origins of life, bioevolution and consciousness. Through effects of impact and/or Auger ionization of donor sites, whole PCS may collapse (spinodal decomposition) into microblocks potentially capable of replication and protobiological activity (DNA analogue). Electronic screening effects may act in RNA fashion by introducing additional length scale(s) to system. Spontaneous quantum computing on charged/neutral sites becomes potential generator of informationally loaded microstructures akin to "Carl Sagan Effect" (hidden messages in Pi in his "Contact") or informational self-organization of "Library of Babel" of J.L. Borges. Even general relativity effects at Planck scale (R.Penrose) may affect the dynamics through (e.g.) isotopic variations of atomic mass and local density (A.A.Berezin, 1992). Thus, PCS can serve as toy model (experimental and computational) at interface of physics and life sciences.

Berezin, Alexander A.

2004-03-01

373

Compensation Following Bilateral Vestibular Damage  

PubMed Central

Bilateral loss of vestibular inputs affects far fewer patients than unilateral inner ear damage, and thus has been understudied. In both animal subjects and human patients, bilateral vestibular hypofunction (BVH) produces a variety of clinical problems, including impaired balance control, inability to maintain stable blood pressure during postural changes, difficulty in visual targeting of images, and disturbances in spatial memory and navigational performance. Experiments in animals have shown that non-labyrinthine inputs to the vestibular nuclei are rapidly amplified following the onset of BVH, which may explain the recovery of postural stability and orthostatic tolerance that occurs within 10?days. However, the loss of the vestibulo-ocular reflex and degraded spatial cognition appear to be permanent in animals with BVH. Current concepts of the compensatory mechanisms in humans with BVH are largely inferential, as there is a lack of data from patients early in the disease process. Translation of animal studies of compensation for BVH into therapeutic strategies and subsequent application in the clinic is the most likely route to improve treatment. In addition to physical therapy, two types of prosthetic devices have been proposed to treat individuals with bilateral loss of vestibular inputs: those that provide tactile stimulation to indicate body position in space, and those that deliver electrical stimuli to branches of the vestibular nerve in accordance with head movements. The relative efficacy of these two treatment paradigms, and whether they can be combined to facilitate recovery, is yet to be ascertained. PMID:22207864

McCall, Andrew A.; Yates, Bill J.

2011-01-01

374

An adaptive guidance algorithm for an aerodynamically assisted orbital plane change maneuver. M.S. Thesis  

NASA Technical Reports Server (NTRS)

Using analysis results from the post trajectory optimization program, an adaptive guidance algorithm is developed to compensate for density, aerodynamic and thrust perturbations during an atmospheric orbital plane change maneuver. The maneuver offers increased mission flexibility along with potential fuel savings for future reentry vehicles. Although designed to guide a proposed NASA Entry Research Vehicle, the algorithm is sufficiently generic for a range of future entry vehicles. The plane change analysis provides insight suggesting a straight-forward algorithm based on an optimized nominal command profile. Bank angle, angle of attack, and engine thrust level, ignition and cutoff times are modulated to adjust the vehicle's trajectory to achieve the desired end-conditions. A performance evaluation of the scheme demonstrates a capability to guide to within 0.05 degrees of the desired plane change and five nautical miles of the desired apogee altitude while maintaining heating constraints. The algorithm is tested under off-nominal conditions of + or -30% density biases, two density profile models, + or -15% aerodynamic uncertainty, and a 33% thrust loss and for various combinations of these conditions.

Blissit, J. A.

1986-01-01

375

Conjugate field approaches for active array compensation  

NASA Astrophysics Data System (ADS)

Two approaches for calculating the compensating feed array complex excitations are namely, the indirect conjugate field matching (ICFM) and the direct conjugate field matching (DCFM) approach. In the ICFM approach the compensating feed array excitations are determined by considering the transmitting mode and the reciprocity principle. The DCF, in contrast calculates the array excitations by integrating directly the induced surface currents on the reflector under a receiving mode. DCFM allows the reflector to be illuminated by an incident plane wave with a tapered amplitude. The level of taper can effectively control the sidelobe level of the compensated antenna pattern. Both approaches are examined briefly.

Acosta, R. J.

1989-07-01

376

Internal and external forces affecting management compensation.  

PubMed

Increasing media scrutiny, eventual implementation of health care reform, and proliferation of TQM/CQI programs are significantly affecting health care management compensation programs. Trustees are insisting that management pay be based on definitive performance standards and are becoming increasingly resistant to the annual increase that is no longer sacrosanct. Philosophical conflicts regarding compensation are developing between CEOs and boards. These external and internal factors will require managers to reassess their attitudes toward their own and subordinate's compensation. Managers, at all levels, will have to adjust to pay determination factors and practices that differ from those to which they have been accustomed. PMID:10130082

Browdy, J D

1993-12-01

377

Mechanisms of X Chromosome Dosage Compensation  

PubMed Central

In many animals, males have one X and females have two X chromosomes. The difference in X chromosome dosage between the two sexes is compensated by mechanisms that regulate X chromosome transcription. Recent advances in genomic techniques have provided new insights into the molecular mechanisms of X chromosome dosage compensation. In this review, I summarize our current understanding of dosage imbalance in general, and then review the molecular mechanisms of X chromosome dosage compensation with an emphasis on the parallels and differences between the three well-studied model systems, M. musculus, D. melanogaster and C. elegans. PMID:25628761

Ercan, Sevin

2015-01-01

378

Droop Compensation with soft Switching for High Voltage Converter Modulator (HVCM)  

SciTech Connect

High Voltage Converter Modulators (HVCM) offer significant performance advantages over conventional modulator technologies for long pulse applications. One of the key advantages of HVCM technology is the ability to compensate for capacitor bank voltage droop. Achieving droop compensation without incurring significant additional switching loss has not been possible in existing designs. This paper presents an analysis of the 'Y-point' variant of the HVCM topology using the Combined Phase and Frequency Modulation (CPFM) technique. This, combined with the addition of a 'lossless' snubber circuit, enables droop compensation while achieving soft switching over the entire pulse duration. The rise time and overshoot of the output voltage pulse is optimized using an iterative extreme seeking algorithm. The optimization reduces the rise time from 100 {micro}s to 50 {micro}s with no overshoot. This will lead to an increase in overall accelerator efficiency.

Bland, Michael [University of Nottingham; Scheinker, Alexander [Los Alamos National Laboratory; Clare, Jon [University of Nottingham; Watson, Alan [University of Nottingham; Ji, Chao [University of Nottingham; Reass, William [Los Alamos National Laboratory

2012-06-04

379

The Atmosphere.  

ERIC Educational Resources Information Center

The composition and dynamics of the earth's atmosphere are discussed, considering the atmosphere's role in distributing the energy of solar radiation received by the earth. Models of this activity which help to explain climates of the past and predict those of the future are also considered. (JN)

Ingersoll, Andrew P.

1983-01-01

380

Atmospheric electricity  

Microsoft Academic Search

Owing to the somewhat explosive development of the science of atmospheric electricity during the past decade this article covers a broad field of activity. The article begins with a description and discussion of the work that has been performed to understand the electrical properties of the basic materials involved in generating processes in the atmosphere, namely ice, water, and sand

C D Stow

1969-01-01

381

Atmospheric Environment ] (  

E-print Network

of neutrally stratified atmospheric boundary layers over heterogeneous terrain. Water Resources Research 42, W (Atmospheric Environment Service, Canada) [Gong, W., Taylor, P.A., Do rnbrack, A., 1996. Turbulent boundary-layer boundary-layer flow over a rough two-dimensional sinusoidal hill. Three different subgrid-scale (SGS

Stoll, Rob

382

Atmospheric chemistry  

SciTech Connect

This book covers the predictive strength of atmospheric models. The book covers all of the major important atmospheric areas, including large scale models for ozone depletion and global warming, regional scale models for urban smog (ozone and visibility impairment) and acid rain, as well as accompanying models of cloud processes and biofeedbacks.

Sloane, C.S. (General Motors Research Labs., Warren, MI (United States)); Tesche, T.W. (Alpine Geophysics (US))

1991-01-01

383

Atmospheric ozone  

NASA Astrophysics Data System (ADS)

The book contains papers given during the All-Union Atmospheric Ozone Conference (Suzdal', October 1988). Papers are presented on the instruments and methodology for measuring atmospheric ozone; results of measurements of ozone, other atmospheric gases, and aerosol; measurements of ozone and of trace gases in the Antarctic; the chemistry and the radiation regime in the ozonosphere; and modeling the ozonosphere. Particular attention is given to reactions between ozone and heterogeneous components of the atmosphere and to changes in tropospheric ozone. It is shown that periods of seismic activity (in particular, earthquakes with values of M not less than 3.5) coincide with short-term (1-2-days long) increases in the atmospheric ozone content.

Kokin, G. A.

384

Pluripotent cells will not dosage compensate  

PubMed Central

Dosage compensation is the mechanism that balances gene expression levels between males and females as well as between the X chromosome and autosomes. In mammals, loss of pluripotency and differentiation are closely linked with the onset of dosage compensation. Pluripotency factors negatively regulate Xist (the non-coding RNA that triggers X chromosome inactivation) and positively regulate Tsix, a repressor of Xist, to inhibit dosage compensation. In addition, X chromosome dose also regulates exit from the pluripotent state. A double dose of X chromosomes in undifferentiated female cells inhibits the MAPK and Gsk3 signaling pathways and activates the Akt pathway, thereby blocking differentiation. Here we review our recent report, which showed that the onset of dosage compensation is also linked to the loss of pluripotency in C. elegans. We discuss these findings in light of what is known about pluripotency and differentiation in this organism. PMID:25254152

Jiang, Jianhao; Lau, Alyssa C; Csankovszki, Gyrgyi

2014-01-01

385

Beam loading compensation for slip stacking  

SciTech Connect

This paper discusses the beam loading compensation requirements to make slip stacking practical in the Fermilab main injector. It also discusses some of the current plans for meeting these requirements with a digital, direct RF feedback system.

James Steimel; Tim Berenc; Claudio Rivetta

2003-06-04

386

77 FR 58469 - Plum Pox Compensation  

Federal Register 2010, 2011, 2012, 2013, 2014

...eligible owners of non-fruit-bearing ornamental tree nurseries and to increase the amount of compensation...owners of commercial stone fruit orchards and fruit tree nurseries whose trees are required to be destroyed in order to prevent...

2012-09-21

387

Compensating for estimation smoothing in kriging  

USGS Publications Warehouse

Smoothing is a characteristic inherent to all minimum mean-square-error spatial estimators such as kriging. Cross-validation can be used to detect and model such smoothing. Inversion of the model produces a new estimator-compensated kriging. A numerical comparison based on an exhaustive permeability sampling of a 4-fr2 slab of Berea Sandstone shows that the estimation surface generated by compensated kriging has properties intermediate between those generated by ordinary kriging and stochastic realizations resulting from simulated annealing and sequential Gaussian simulation. The frequency distribution is well reproduced by the compensated kriging surface, which also approximates the experimental semivariogram well - better than ordinary kriging, but not as well as stochastic realizations. Compensated kriging produces surfaces that are more accurate than stochastic realizations, but not as accurate as ordinary kriging. ?? 1996 International Association for Mathematical Geology.

Olea, R.A.; Pawlowsky, Vera

1996-01-01

388

Asymmetric-hysteresis compensation in piezoelectric actuators  

NASA Astrophysics Data System (ADS)

The advantages of using piezoelectric actuators in ultra-precision applications are often impaired by nonlinear effects, in particular hysteresis, which may lead to positioning uncertainties of up to 15% of the actuator's stroke. Model-based compensation strategies are often prescribed in order to overcome this limitation and achieve better dynamical accuracy. This comes, however, at the expense of increasing identification and implementation complexity, especially when hysteresis is of the asymmetric type, such as prevalent in hard piezoceramic materials. This paper proposes a new compensation strategy based upon (i) treating hysteresis as being separate from other dynamical effects and (ii) formulating a new, simplified model to deal with asymmetric hysteresis, based on applying a linear operator to the conventional hysteresis models. After developing the theoretical background of the compensation strategy, the accuracy improvement due to the new hysteresis-compensation method is demonstrated experimentally.

Aguirre, Gorka; Janssens, Thierry; Van Brussel, Hendrik; Al-Bender, Farid

2012-07-01

389

Workers compensation: coverage, benefits, and costs, 1982  

SciTech Connect

Workers compensation provides medical care and income maintenance protection to workers disabled from work-related injury or illness. This program is of considerable interest to the Social Security Administration (SSA) from several perspectives. For example, since 1965 Social Security Disability Insurance (DI) benefits and workers compensation payments have been integrated. Information on the experience under workers compensation provides a framework for examining questions concerning gaps and overlaps in the Nation's social insurance system. In addition, since December 1969 SSA has administered claims filed through 1973 under part B of the Black Lung program--the program providing income maintenance protection to coal miners disabled by pneumoconiosis. The workers compensation experience reported here consists of information on benefits for work-related injury and disease, including data on the combined benefits paid under the entire Federal Black Lung program administered by the Labor Department and SSA.

Price, D.N.

1984-12-01

390

7 CFR 930.61 - Handler compensation.  

Code of Federal Regulations, 2011 CFR

...OF AGRICULTURE TART CHERRIES GROWN IN THE STATES OF MICHIGAN, NEW YORK, PENNSYLVANIA, OREGON, UTAH, WASHINGTON, AND WISCONSIN Order Regulating Handling Regulations 930.61 Handler compensation. Each handler handling cherries from a...

2011-01-01

391

CEO compensation: a question of ethics  

E-print Network

reporting as the method chosen can greatly affect compensation expense, both in size and consistency, and thus manage earnings. This paper will focus on both deontological and teleological ethical models in order to show the inherent inconsistencies...

Cole, James Harrison

2013-02-22

392

Temperature compensated two-mode fiber interferometer  

E-print Network

In this thesis we propose an innovative approach of designing and implementing a temperature compensated two-mode optical fiber interferometer in a control system of stabilizing the wavelength of a laser. We give the procedure for designing...

Doma, Jagdish Ramchandra

1993-01-01

393

28 CFR 345.54 - Overtime compensation.  

Code of Federal Regulations, 2011 CFR

...Overtime compensation. 345.54 Section 345.54 Judicial Administration FEDERAL PRISON INDUSTRIES, INC., DEPARTMENT OF JUSTICE FEDERAL PRISON INDUSTRIES (FPI) INMATE WORK PROGRAMS Inmate Pay and Benefits 345.54...

2011-07-01

394

28 CFR 345.54 - Overtime compensation.  

Code of Federal Regulations, 2010 CFR

...Overtime compensation. 345.54 Section 345.54 Judicial Administration FEDERAL PRISON INDUSTRIES, INC., DEPARTMENT OF JUSTICE FEDERAL PRISON INDUSTRIES (FPI) INMATE WORK PROGRAMS Inmate Pay and Benefits 345.54...

2010-07-01

395

28 CFR 345.54 - Overtime compensation.  

Code of Federal Regulations, 2014 CFR

...Overtime compensation. 345.54 Section 345.54 Judicial Administration FEDERAL PRISON INDUSTRIES, INC., DEPARTMENT OF JUSTICE FEDERAL PRISON INDUSTRIES (FPI) INMATE WORK PROGRAMS Inmate Pay and Benefits 345.54...

2014-07-01

396

GENDER EQUITY ASSESSMENT: Faculty Compensation and Headcounts  

E-print Network

GENDER EQUITY ASSESSMENT: Faculty Compensation and Headcounts May 2013 #12; 2 | P a g e CONTENTS GENDER EQUITY IN THE COLLEGE OF LIBERAL ARTS ..................................................................................................... 4 Figure 1: Academic Rate by Gender for Full Professors

Texas at Austin, University of

397

Modified univibrator compensates for output timing errors  

NASA Technical Reports Server (NTRS)

One-stage, delay compensation amplifier, added to conventional univibrator circuitry time-synchronizes the trailing edge of the output pulse with the origin of the input pulse. The trailing edge is independent of the amplitude of the input pulse.

Strauss, M. G.

1967-01-01

398

Linear attenuation coefficients for compensator based imrt  

Microsoft Academic Search

With rapid technological improvements in computer driven 3-D radiotherapy treatment planning systems (RTPS) the use of compensating\\u000a filters for intensity modulated radiation therapy (IMRT) will dramatically increase the ease of treatment. The procedure for\\u000a commissioning .decimal (Sanford, Florida) compensators involved the measurement of the effective linear attenuation coefficients\\u000a for aluminium and brass. Field sizes to be measured vary from small

T. Bartrum; M. Bailey; V. Nelson; M. Grace

2007-01-01

399

Dosage compensation and chromatin structure in Drosophila  

Microsoft Academic Search

The past year has brought significant advances in our understanding of the male-specific lethal (msl) genes and dosage compensation in Drosophila. The molecular characterization of the msl-2 gene has, to a great extent, solved the question of how msl-mediated dosage compensation is restricted to males. Molecular analyses of the msl genes have substantiated the proposal that the MSL proteins function

Greg J Bashaw; Bruce S Baker

1996-01-01

400

Chromatin Mechanisms in Drosophila Dosage Compensation  

Microsoft Academic Search

Dosage compensation ensures that males and females equalize the expression of the X-linked genes and therefore provides an exquisite model system to study chromosome-wide transcription regulation. In Drosophila, this is achieved by hyper-transcription of the genes on the male X chromosome. This process requires an RNA\\/protein-containing dosage compensation complex. Here, we discuss the current status of the known Drosophila complex

Mikko Taipale; Asifa Akhtar

401

High-power 355 nm third-harmonic generation with effective walk-off compensation of LBO  

NASA Astrophysics Data System (ADS)

Walk-off compensation using wedged cut type-II LBO was investigated theoretically and experimentally. An algorithm is proposed to find the optimized wedged cut angle to compensate the walk-off effect completely. Using a pulsed Nd:Y V O4 MOPA laser as the fundamental frequency infrared (IR) source, 36.3 W 355 nm frequency converted ultraviolet (UV) light was obtained using an optimized wedged cut type-II LBO for walk-off compensated third-harmonic generation (THG), giving a conversion efficiency of 37.1% from IR to UV. A comparative experiment using a conventional cut type-II LBO was also implemented. The results indicate that optimized wedged cutting of type-II LBO is an effective approach for walk-off compensation in efficient THG. The output performance of angle and temperature tuning for wedged cut type-II LBO was also investigated.

Yan, Xingpeng; Liu, Qiang; Pei, Chuang; Wang, Dongsheng; Gong, Mali

2014-04-01

402

Discrete Packet Analysis for Improved Atmospheric Rejection on Modulated Laser Signals  

SciTech Connect

This slide-show discusses how the method of discrete packet analysis improves atmospheric compensation for quasi-CW fluorescence detection methods. This is key to improving remote sensing capabilities.

O'Neill, M., McKenna, I., DiBenedetto, J., Capelle, G., Trainham, R.

2012-07-19

403

Compensation for non-uniform attenuation in SPECT brain imaging  

SciTech Connect

Photon attenuation is a major limitation in performing quantitative SPECT brain imaging. A number of methods have been proposed for compensation of attenuation in regions of the body that can be modelled as a uniform attenuator. The magnitude of the errors introduced into reconstructed brain images by assuming the head to be a uniform attenuator are uncertain (the skull, sinus cavities and head holder all have different attenuation properties than brain tissue). Brain imaging is unique in that the radioisotope, for the most part, is taken up within a uniform attenuation medium (i.e., brain tissue) which is surrounded by bone (i.e., the skull) of a different density. Using this observation, Bellini`s method for attenuation compensation (which is an exact solution to the exponential Radon transform) has been modified to account for the different attenuation properties of the skull. To test this modified Bellini method, a simple mathematical phantom was designed to model the brain and a skull of varying thickness less than 7.5 mm. To model brain imaging with Tc-99m HMPAO, the attenuation coefficient of the brain tissue and skull were set to 0.15 cm{sup -1} and 0.22 cm{sup -1} respectively. A ray-driven projector which accounted for non-uniform attenuation was used to simulate projection data from 128 views. The detector response and scatter were not simulated. It was observed that reconstructions processed with uniform attenuation compensation (i.e., where it was assumed that the brain tissue and the skull had the same attenuation coefficient) provided errors of 6-20%, whereas those processed with the non-uniform Bellini algorithm were biased by only 0-5%.

Glick, S.J.; King, M.A.; Pan, T.S. [Univ. of Massachusetts Medical Center, Worcester, MA (United States)] [and others

1994-05-01

404

Complex amplitude correlation for compensation of large in-plane motion in digital speckle pattern interferometry  

SciTech Connect

The use of complex amplitude correlation to compensate for large in-plane motion in digital speckle pattern interferometry is investigated. The result is compared with experiments where digital speckle photography (DSP) is used for compensation. An advantage of using complex amplitude correlation instead of intensity correlation (as in DSP) is that the phase change describing the deformation is retrieved directly from the correlation peak, and there is no need to compensate for the large movement and then use the interferometric algorithms. A discovered drawback of this method is that the correlation values drop quickly if a phase gradient larger than {pi} is present in the subimages used for cross correlation. This means that, for the complex amplitude correlation to be used, the size of the subimages must be well chosen or a third parameter in the cross-correlation algorithm that compensates for the phase variation is needed.Correlation values and wrapped phase maps from the two techniques (intensity and complex amplitude correlation) are presented.

Svanbro, Angelica; Sjoedahl, Mikael

2006-12-01

405

EUV multilayer defect compensation (MDC) by absorber pattern modification: from theory to wafer validation  

NASA Astrophysics Data System (ADS)

According to the ITRS roadmap, mask defects are among the top technical challenges to introduce extreme ultraviolet (EUV) lithography into production. Making a multilayer defect-free extreme ultraviolet (EUV) blank is not possible today, and is unlikely to happen in the next few years. This means that EUV must work with multilayer defects present on the mask. The method proposed by Luminescent is to compensate effects of multilayer defects on images by modifying the absorber patterns. The effect of a multilayer defect is to distort the images of adjacent absorber patterns. Although the defect cannot be repaired, the images may be restored to their desired targets by changing the absorber patterns. This method was first introduced in our paper at BACUS 2010, which described a simple pixel-based compensation algorithm using a fast multilayer model. The fast model made it possible to complete the compensation calculations in seconds, instead of days or weeks required for rigorous Finite Domain Time Difference (FDTD) simulations. Our SPIE 2011 paper introduced an advanced compensation algorithm using the Level Set Method for 2D absorber patterns. In this paper the method is extended to consider process window, and allow repair tool constraints, such as permitting etching but not deposition. The multilayer defect growth model is also enhanced so that the multilayer defect can be "inverted", or recovered from the top layer profile using a calibrated model.

Pang, Linyong; Hu, Peter; Satake, Masaki; Tolani, Vikram; Peng, Danping; Li, Ying; Chen, Dongxue

2011-11-01

406

New Spectrum Leakage Correction Algorithm for Frequency Estimation of Power System Signals  

Microsoft Academic Search

A new algorithm for the estimation of the frequency of single-tone signals is presented in this paper. The algorithm works in the frequency domain and is based on best fitting a theoretical spectrum of a single-tone signal that is windowed using a rectangular window on the spectrum of the sampled signal. Using this iterative process, the algorithm compensates the spectrum

Toms Radil; Pedro M. Ramos; A. Cruz Serra

2009-01-01

407

A NEW VoIP ADAPTIVE PLAYOUT ALGORITHM M. Narbutt*, L.Murphy*  

E-print Network

A NEW VoIP ADAPTIVE PLAYOUT ALGORITHM M. Narbutt*, L.Murphy* *Department of Computer Science Keywords: jitter compensation, playout buffer algorithm Abstract A novel playout algorithm for VoIP Introduction A typical VoIP application buffers incoming packets at the receiver and artificially delays

408

Decorrelation control by the cerebellum achieves oculomotor plant compensation in simulated vestibulo-ocular reflex.  

PubMed Central

We introduce decorrelation control as a candidate algorithm for the cerebellar microcircuit and demonstrate its utility for oculomotor plant compensation in a linear model of the vestibulo-ocular reflex (VOR). Using an adaptive-filter representation of cerebellar cortex and an anti-Hebbian learning rule, the algorithm learnt to compensate for the oculomotor plant by minimizing correlations between a predictor variable (eye-movement command) and a target variable (retinal slip), without requiring a motor-error signal. Because it also provides an estimate of the unpredicted component of the target variable, decorrelation control can simplify both motor coordination and sensory acquisition. It thus unifies motor and sensory cerebellar functions. PMID:12350251

Dean, Paul; Porrill, John; Stone, James V

2002-01-01

409

Imaging algorithm for steadily flying and maneuvering big targets  

Microsoft Academic Search

Usually inverse synthetic aperture radar (ISAR) imaging is for small aircraft, with long range, moreover the coherent integration angle is small, that is the target's wavenumber spectrum support region can be regard as a rectangle, Range-Doppler(RD) algorithm or Range-Instantaneous-Doppler (RID) algorithm are employed for image reconstruction after translational motion compensation (TMC), which includes envelope alignment (such as envelope correlation algorithm,

Mengdao Xing; Zheng Bao

2001-01-01

410

Temperature compensated 1 GHz STW based multifrequency oscillator  

NASA Astrophysics Data System (ADS)

The temperature compensation of a 1 GHz VCO, stabilized with a SSBW/ STW combined mode resonator filter, has been achieved at 128 frequencies. Analogue and digital compensation techniques are used. The analogue compensation is common for all frequencies, and the digital compensation is individual. The overall instability for each of the frequencies is +/- 2 ppm over the temperature range - 30 to 60deg C.

Taslakov, M. A.

1993-05-01

411

Wind Drift Compensation in Migrating Dragonflies Pantala (Odonata: Libellulidae)  

Microsoft Academic Search

Tailwind drift compensation serves to maximize a migrant's flight distance on a given amount of energy, and crosswind drift compensation serves to hold a course true and minimize the distance flown. With full or part compensation, airspeeds are predicted to increase with greater crosswind drift. To test whether migrating dragonflies compensated for wind drift, I measured the velocity and heading

Robert B. Srygley

2003-01-01

412

Bilinear Compensed Generalized Predictive Control: An Adaptive Approach  

Microsoft Academic Search

The present paper presents an adaptive implementation of bilinear compensed generalized predictive control. The bilinear compensated model adds a compensation term in bilinear model wich minimize the prediction error variance generated by its linearization. Since the relation between the prediction error and the control signal is nonlinear, and the compensation term model is linear, a different model may be estimated

Adhemar de Barros Fontes; Andr Laurindo Maitelli; Anderson Luiz de Oliveira

413

Freebal: dedicated gravity compensation for the upper extremities  

Microsoft Academic Search

In most upper-extremity rehabilitation robotics, several components affect the therapy outcome. A common component is gravity compensation which alleviates upper-extremity movements. Gravity compensation by itself could improve motor control further or faster, separate from other effects of robotic therapy. To investigate the rehabilitation value of gravity compensation separately, we created the dedicated gravity compensation system, Freebal. The sling systems with

Amo H. A. Stienen; E. E. G. Hekman; G. B. Prange; M. J. A. Jannink; A. M. M. Aalsma; H. Van der Kooij

2007-01-01

414

WILDLIFE DAMAGE AND AGRICULTURE :AD YNAMIC ANALYSIS OF COMPENSATION SCHEMES  

Microsoft Academic Search

We study the environmental and economic consequences of introducing a program to compensate peasants for damages caused by wildlife. We show that the widely held belief that compensation induces wildlife conservation may be erroneous. In a partially open economy, compensation can lower the wildlife stock and result in a net welfare loss for local people. In an open economy, compensation

DANIEL RONDEAU; ERWIN BULTE

2007-01-01

415

UCF Re-employment Compensation Process Background Information  

E-print Network

1 UCF Re-employment Compensation Process Background Information: Re-employment compensation position. Re-employment compensation is a federal-state partnership based upon federal law but it is administered at the state level. Re-employment compensation is a temporary, partial wage replacement

Wu, Shin-Tson

416

Employer Costs for Employee Compensation, 1966-98  

NSDL National Science Digital Library

According to Employer Costs for Employee Compensation, 1986-98 from the US BLS, employer compensation costs for retirement benefits in the private sector accounted for 8.5 percent of total compensation in 1998, compared to 5.4 percent of total compensation in 1966.

1998-01-01

417

Variability Compensation using NAP for Unconstrained Face Recognition  

E-print Network

Variability Compensation using NAP for Unconstrained Face Recognition Pedro Tome, Ruben Vera compensation scheme based on the Nui- sance Attribute Projection (NAP) that can be applied to compensate, a variability compensation approach based on Nuisance Attribute Projection (NAP) is presented for face

Autonoma de Madrid, Universidad

418

Friction Problems in Servomechanisms: Modeling and Compensation Techniques  

E-print Network

Friction Problems in Servomechanisms: Modeling and Compensation Techniques Jan Tommy Gravdahl of this presentation Introduction Friction models 1. Static models 2. Models with time delay 3. Dynamic models Friction compensation 1. Non-model based compensation 2. Compensation based on static friction models 3

Gravdahl, Jan Tommy

419

Non-Iterative Regularized reconstruction Algorithm for Non-CartesiAn MRI: NIRVANA  

Microsoft Academic Search

We introduce a novel noniterative algorithm for the fast and accurate reconstruction of nonuniformly sampled MRI data. The proposed scheme derives the reconstructed image as the nonuniform inverse Fourier transform of a compensated dataset. We derive each sample in the compensated dataset as a weighted linear combination of a few measured k-space samples. The specific k-space samples and the weights

Satyananda Kashyap; Zhili Yang; Mathews Jacob

2011-01-01

420

Combined system for the compensation of the solar pressure-induced disturbing torque for geostationary satellites  

NASA Astrophysics Data System (ADS)

The problem is considered of determining the shape and dimensions of the passive component in a combined system for offsetting the solar pressure-induced disturbing torque for geostationary spacecraft with asymmetrical solar arrays. The problem statement, numerical solution algorithm, and calculated results are presented. The resulting shape, the study suggests, not only has the required compensation properties but is also the most efficient from the standpoint of manufacture and functional reliability.

Shmatov, S. I.; Mordvinkin, A. S.

2014-12-01

421

IC for motion-compensated 100 Hz TV with natural-motion movie-mode  

Microsoft Academic Search

An IC for consumer 100 Hz television has been designed and is described in this paper. It applies motion estimation and compensation algorithms for high-quality field rate upconversion and a judder-free motion portrayal of movie material. Noise reduction and vertical zoom are also included on-chip. The IC processes luminance as well as chrominance, and automatically adapts to movie-material. A new

G. de Haan; J. Kettenis; A. Loning; B. De Loore

1996-01-01

422

On-line nonuniformity and temperature compensation of uncooled IRFPAs using embedded digital hardware  

NASA Astrophysics Data System (ADS)

We present a model and a signal-processing algorithm for compensating the nonuniformity (NU) noise and surrounding temperature self-heating e ects on the response of uncooled microbolometer-based infrared cameras. The model for the NU noise considers pixelwise gain and o set parameters. The representation for the self-heating dynamics of the camera is an autoregressive moving average (ARMA) model for camera's internal temperature. The algorithm performs initially a two-point calibration at a known surrounding temperature. Next, without modifying the NU parameters, we dynamically compensate variations in the camera readout using both estimates of the ARMA model and measurements of the surrounding temperature taken by a simple sensor embedded in the camera. Tested on a CEDIP Jade UC33 camera, our system compensates reference black-body images at 30 degrees Celsius, with a peak error below 1.3 and a mean error below 0.3 degrees Celsius, in scenarios where the room temperature varied up to 14 degrees Celsius. Moreover, the regularity and simplicity of the algorithm enables us to implement it on embedded digital hardware, thereby reducing its cost, size, and power consumption. We implemented the algorithm on a Xilinx XC6SLX45 FPGA using xed-point arithmetic. The circuit exhibits an arithmetic error of 0.06 degrees compared to a software double-precision implementation. It compensates 320 240-pixel video at up to 1,437 fps and 640 480-pixel video at up to 360 fps, using 1% of the logic resources of the FPGA, and less than 1 mW of dynamic power at 110 MHz. Adding Gigabit Ethernet communication, HDMI display, and a pseudocolor map on the chip uses 10% of the resources and consumes 915 mW.

Wolf, Alejandro; Redlich, Rodolfo; Figueroa, Miguel; Pezoa, Jorge E.

2013-09-01

423

The design and implement of incorporate system for power harmonicdetection and compensation based on embedded platform  

Microsoft Academic Search

In view of the specific features of the current harmonic monitoring system, especially the difficulty in realizing complex algorithms, a new method which adopts S3C2410 and embedded Linux platform to construct a new harmonic monitoring system is designed in this paper. It also provides graphic user interface by using QT\\/Embedded library and harmonic compensation system based on the improved method

Jianhua Li; Wenhua Li; Yongliang Hu

2010-01-01

424

Net-Shape Forging of Aerofoil Blade based on Flash Trimming and Compensation methods  

SciTech Connect

In this research, an automatic blade forging die shape optimisation system was developed by using direct compensation and flash trimming algorithms and integrating with the DEFORM 3D software package. To validate the developed system, a 3D blade forging case problem was simulated and optimised with and without the consideration of trimming simulation. The results were compared with actual measurement data of the forged aerofoil blade with excellent results obtained with the fast trimming simulation procedure used.

Lu, B. [Department of Plasticity Forming Engineering, Shanghai Jiao Tong University, Shanghai, 200030 (China); Ou, H. [Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, Nottingham, NG7 2RD (United Kingdom); Armstrong, C. G. [School of Mechanical and Aerospace Engineering, Queen's University Belfast, Belfast, BT9 5AH (United Kingdom)

2011-05-04

425

Atmospheric tritium  

SciTech Connect

Research progress for the year 1979 to 1980 are reported. Concentrations of tritiated water vapor, tritium gas and tritiated hydrocarbons in the atmosphere at selected sampling points are presented. (ACR)

Oestlund, H.G.; Mason, A.S.

1980-01-01

426

Exoplanet Atmospheres  

E-print Network

At the dawn of the first discovery of exoplanets orbiting Sun-like stars in the mid-1990s, few believed that observations of exoplanet atmospheres would ever be possible. After the 2002 Hubble Space Telescope detection of ...

Seager, Sara

427

Earth's Atmosphere  

NSDL National Science Digital Library

This problem set is about the methods scientists use to compare the abundance of the different elements in Earth's atmosphere. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

2012-08-03

428

Atmospheric Environment ] (  

E-print Network

Elsevier Ltd. All rights reserved. Keywords: 3-D CTM; Tropospheric ozone; Air quality; Ozone precursors 1 or hemispheric ozone background as an external influence on Europe's air quality in the light of the continuingAtmospheric Environment ] (

429

Algorithmic Learning.  

ERIC Educational Resources Information Center

This volume contains a series of papers on algorithmic learning. Included are six reviews of research pertaining to various aspects of algorithmic learning, six reports of pilot experiments in this area, a theoretical discussion of "The Conditions for Algorithmic Imagination," and an annotated bibliography. All the papers assume a common

Suydam, Marilyn N., Ed.; Osborne, Alan R., Ed.

430

Numerical Algorithms  

NSDL National Science Digital Library

CSC 325. (MAT 325) Numerical Algorithms (3) Prerequisite: CSC 112 or 121, MAT 162. An introduction to the numerical algorithms fundamental to scientific computer work. Includes elementary discussion of error, polynomial interpolation, quadrature, linear systems of equations, solution of nonlinear equations and numerical solution of ordinary differential equations. The algorithmic approach and the efficient use of the computer are emphasized.

Dr Gene Tagliarini

431

Vibration isolation and pressure compensation apparatus for sensitive instrumentation  

NASA Technical Reports Server (NTRS)

A system for attenuating the inherent vibration associated with a mechanical refrigeration unit employed to cryogenically cool sensitive instruments used in measuring chemical constituents of the atmosphere is described. A modular system including an instrument housing and a reaction bracket with a refrigerator unit floated there between comprise the instrumentation system. A pair of evacuated bellows that "float' refrigerator unit and provide pressure compensation at all levels of pressure from seal level to the vacuum of space. Vibration isolators and when needed provide additional vibration damping for the refrigerator unit. A flexible thermal strap (20 K) serves to provide essentially vibration free thermal contact between cold tip of the refrigerator unit and the instrument component mounted on the IDL mount. Another flexible strap (77 K) serves to provide vibration free thermal contact between the TDL mount thermal shroud and a thermal shroud disposed about the thermal shaft.

Averill, R. D. (inventor)

1983-01-01

432

Atmospheric Dust  

NSDL National Science Digital Library

Millions of tons of dust are lifted from deserts annually, suspended in the atmosphere, and released to fall on the oceans, but scientists are a long way from understanding the impact of atmospheric dust on the climate and weather systems of Earth or on marine organisms. This radio broadcast explains how the nitrogen, phosphorus and iron released from dust boosts the growth of phytoplankton, which also soak up carbon dioxide and release more gases into the atmosphere. Better monitoring and more sophisticated sensors are giving us a more accurate picture of the dust in the atmosphere; the broadcast reports on investigations of dust from ice cores and on computer simulations of the connections between dust and climate. But the unpredictable nature of dust events makes it extremely difficult to determine their impact on the natural systems of Earth. There are discussions with geographers, oceanographers, environmentalists and climate modelers about atmospheric dust, one of the least understood and most contradictory components of the atmosphere. The broadcast is 28 minutes in length.

433

Executive perks: Compensation and corporate performance in China  

Microsoft Academic Search

Many studies have examined CEO compensation in developed countries, where a long tradition of disclosure renders data readily\\u000a available. In emerging economies, particularly in China, where market-based compensation is a relatively new phenomenon, there\\u000a are few studies of CEO compensation. In addition, information on the use of non-cash compensation is almost absent. Building\\u000a on the general literature on CEO compensation,

Pattarin Adithipyangkul; Ilan Alon; Tianyu Zhang

2011-01-01

434

Compensation method for random drifts of laser beams based on moving average feedback control  

NASA Astrophysics Data System (ADS)

In order to eliminate the measurement errors caused by the instability of laser beams, a real-time compensation algorithms for the random drifts of laser beams based on moving average (MA) correction mechanism was presented. By establishing a correction model with two fast steering mirrors in the beam delivery path and analyzing the pulse to pulse beam fluctuation, a real-time beam drifts correction is implemented based on closed loop feedback control, which especially focuses on reducing the pulse to pulse drifts and ground fluctuations. The simulation results show that this algorithm can control beam drifts effectively. Optimal MA can be reduced to 3n-1/2 times (n--pulse numbers in a window) without the ground vibrations. There are a series of improvements on the moving standard deviation (MSD) as well. MSD get a sudden decline at the window pulse. Meanwhile, the drifts can be restrained while loading the ground vibrations without any big jump, and the dropping amplitude is bigger than without the ground vibration. MSD drop while the whole system is controlled by this compensation method and the results are stable. The key of this compensation method for random drifts of laser beams based on moving average feedback control lies in the appropriate corrections formula. What is more, this algorithm which is practical can achieve high precision control of direction drifts.

Zhang, Lixia; Wang, Ruilin; Lin, Wumei; Liao, Zhijie

2012-10-01

435

76 FR 49398 - Non-Discrimination in Compensation; Compensation Data Collection Tool  

Federal Register 2010, 2011, 2012, 2013, 2014

...Compensation Data Collection Tool AGENCY: Office of Federal...compensation data collection tool. Possible uses for the...warrant further review or evaluation by OFCCP or contractor...data collected by the tool to conduct analyses at...any of the following methods: Federal...

2011-08-10

436

Risk compensation behaviours in construction workers' activities.  

PubMed

The purpose of this study was to test whether the construction workers have the tendency of engaging in risk compensation behaviours, and identify the demographic variables, which may influence the extent to which the construction workers may show risk compensation behaviours. Both quantitative (survey) and qualitative (interviews) approaches were used in this study. A questionnaire survey was conducted with all the construction workers on three building construction sites of a leading construction company in Australia. Semi-structured interviews were then conducted to validate the findings of the quantitative research. The findings indicate that workers tend to show risk compensation behaviours in the construction environment. The workers with more working experience, higher education, or having never been injured at work before have a higher tendency to show risk compensation in their activities than the others. The implication is that contractors need to assess the potential influence of workers' risk compensation behaviours when evaluating the effect of risk control measures. It is recommended that supervisors pay more attention to the behavioural changes of those workers who have more experience, higher education, and have never been injured before after the implementation of new safety control measures on construction site. PMID:24134314

Feng, Yingbin; Wu, Peng

2015-03-01

437

Temperature compensation and entrainment in circadian rhythms  

NASA Astrophysics Data System (ADS)

To anticipate daily variations in the environment and coordinate biological activities into a daily cycle many organisms possess a circadian clock. In the absence of external time cues the circadian rhythm persists with a period of approximately 24?h. The clock phase can be shifted by single pulses of light, darkness, chemicals, or temperature and this allows entrainment of the clock to exactly 24 h by cycles of these zeitgebers. On the other hand, the period of the circadian rhythm is kept relatively constant within a physiological range of constant temperatures, which means that the oscillator is temperature compensated. The mechanisms behind temperature compensation and temperature entrainment are not fully understood, neither biochemically nor mathematically. Here, we theoretically investigate the interplay of temperature compensation and entrainment in general oscillatory systems. We first give an analytical treatment for small temperature shifts and derive that every temperature-compensated oscillator is entrainable to external small-amplitude temperature cycles. Temperature compensation ensures that this entrainment region is always centered at the endogenous period regardless of possible seasonal temperature differences. Moreover, for small temperature cycles the entrainment region of the oscillator is potentially larger for rectangular pulses. For large temperature shifts we numerically analyze different circadian clock models proposed in the literature with respect to these properties. We observe that for such large temperature shifts sinusoidal or gradual temperature cycles allow a larger entrainment region than rectangular cycles.

Bodenstein, C.; Heiland, I.; Schuster, S.

2012-06-01

438

Rapid springback compensation for age forming based on quasi Newton method  

NASA Astrophysics Data System (ADS)

Iterative methods based on finite element simulation are effective approaches to design mold shape to compensate springback in sheet metal forming. However, convergence rate of iterative methods is difficult to improve greatly. To increase the springback compensate speed of designing age forming mold, process of calculating springback for a certain mold with finite element method is analyzed. Springback compensation is abstracted as finding a solution for a set of nonlinear functions and a springback compensation algorithm is presented on the basis of quasi Newton method. The accuracy of algorithm is verified by developing an ABAQUS secondary development program with MATLAB. Three rectangular integrated panels of dimensions 710 mm 750 mm integrated panels with intersected ribs of 10 mm are selected to perform case studies. The algorithm is used to compute mold contours for the panels with cylinder, sphere and saddle contours respectively and it takes 57%, 22% and 33% iterations as compared to that of displacement adjustment (DA) method. At the end of iterations, maximum deviations on the three panels are 0.618 4 mm, 0.624 1 mm and 0.342 0 mm that are smaller than the deviations determined by DA method (0.740 8 mm, 0.740 8 mm and 0.713 7 mm respectively). In following experimental verification, mold contour for another integrated panel with 400 mm380 mm size is designed by the algorithm. Then the panel is age formed in an autoclave and measured by a three dimensional digital measurement devise. Deviation between measuring results and the panel's design contour is less than 1 mm. Finally, the iterations with different mesh sizes (40 mm, 35 mm, 30 mm, 25 mm, 20 mm) in finite element models are compared and found no considerable difference. Another possible compensation method, Broyden-Fletcher-Shanmo method, is also presented based on the solving nonlinear functions idea. The Broyden-Fletcher-Shanmo method is employed to compute mold contour for the second panel. It only takes 50% iterations compared to that of DA. The proposed method can serve a faster mold contour compensation method for sheet metal forming.

Xiong, Wei; Gan, Zhong; Xiong, Shipeng; Xia, Yushan

2014-05-01

439

Compensation neurosis: a too quickly forgotten concept?  

PubMed

There has been great debate concerning the existence and meaning of compensation neurosis. It is included in the International Classification of Diseases (ICD)-9 and -10 but not listed in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR). On the eve of publication of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), we re-examine the history and concept of compensation neurosis and conceptually update the condition to reflect current psychiatric thought. We consider its utility as a diagnostic entity for forensic evaluations and its components as they relate to exaggeration in injury claims. We also discuss how compensation neurosis differs from malingering and factitious disorder. PMID:22960922

Hall, Ryan C W; Hall, Richard C W

2012-01-01

440

Attitude control compensator for flexible spacecraft  

NASA Technical Reports Server (NTRS)

An attitude control loop for a spacecraft uses a proportional-integral-derivative (PID) controller for control about an axis. The spacecraft body has at least a primary mechanical resonance. The attitude sensors are collocated, or both on the rigid portion of the spacecraft. The flexure attributable to the resonance may result in instability of the system. A compensator for the control loop has an amplitude response which includes a component which rolls off beginning at frequencies below the resonance, and which also includes a component having a notch at a notch frequency somewhat below the resonant frequency. The phase response of the compensator tends toward zero at low frequencies, and tends toward -180.degree. as frequency increases toward the notch frequency. At frequencies above the notch frequency, the phase decreases from +180.degree., becoming more negative, and tending toward -90.degree. at frequencies far above the resonance frequency. Near the resonance frequency, the compensator phase is near zero.

Goodzeit, Neil E. (Inventor); Linder, David M. (Inventor)

1991-01-01

441

Reexamining workers' compensation: a human rights perspective.  

PubMed

Injured workers, particularly those with more severe injuries, have long experienced workers' compensation systems as stressful and demeaning, have found it difficult to obtain benefits, and, when able to obtain benefits, have found them inadequate. Moreover, the last two decades have seen a substantial erosion of the protections offered by workers' compensation. State after state has erected additional barriers to benefit receipt, making the workers' compensation experience even more difficult and degrading. These changes have been facilitated by a framing of the political debate focused on the free market paradigm, employer costs, and worker fraud and malingering. The articles in this special issue propose an alternate framework and analysis, a human rights approach, that values the dignity and economic security of injured workers and their families. PMID:22570018

Boden, Leslie I

2012-06-01

442

Wavefront sensors and algorithms for adaptive optical systems  

NASA Astrophysics Data System (ADS)

The results of recent works related to techniques and algorithms for wave-front (WF) measurement using Shack-Hartmann sensors show their high efficiency in solution of very different problems of applied optics. The goal of this paper was to develop a sensitive Shack-Hartmann sensor with high precision WF measurement capability on the base of modern technology of optical elements making and new efficient methods and computational algorithms of WF reconstruction. The Shack-Hartmann sensors sensitive to small WF aberrations are used for adaptive optical systems, compensating the wave distortions caused by atmospheric turbulence. A high precision Shack-Hartmann WF sensor has been developed on the basis of a low-aperture off-axis diffraction lens array. The device is capable of measuring WF slopes at array sub-apertures of size 640640 ?m with an error not exceeding 4.80 arcsec (0.15 pixel), which corresponds to the standard deviation equal to 0.017? at the reconstructed WF with wavelength ? . Also the modification of this sensor for adaptive system of solar telescope using extended scenes as tracking objects, such as sunspot, pores, solar granulation and limb, is presented. The software package developed for the proposed WF sensors includes three algorithms of local WF slopes estimation (modified centroids, normalized cross-correlation and fast Fourierdemodulation), as well as three methods of WF reconstruction (modal Zernike polynomials expansion, deformable mirror response functions expansion and phase unwrapping), that can be selected during operation with accordance to the application.

Lukin, V. P.; Botygina, N. N.; Emaleev, O. N.; Konyaev, P. A.

2010-07-01

443

Representing Range Compensators with Computational Geometry in TOPAS  

SciTech Connect

In a proton therapy beamline, the range compensator modulates the beam energy, which subsequently controls the depth at which protons deposit energy. In this paper, we introduce two computational representations of range compensator. One of our compensator representations, which we refer to as a subtraction solid-based range compensator, precisely represents the compensator. Our other representation, the 3D hexagon-based range compensator, closely approximates the compensator geometry. We have implemented both of these compensator models in a proton therapy Monte Carlo simulation called TOPAS (Tool for Particle Simulation). In the future, we will present a detailed study of the accuracy and runtime performance trade-offs between our two range compensator representations.

Iandola, Forrest N.; /Illinois U., Urbana /SLAC

2012-09-07

444

Gigabit Ethernet Asynchronous Clock Compensation FIFO  

NASA Technical Reports Server (NTRS)

Clock compensation for Gigabit Ethernet is necessary because the clock recovered from the 1.25 Gb/s serial data stream has the potential to be 200 ppm slower or faster than the system clock. The serial data is converted to 10-bit parallel data at a 125 MHz rate on a clock recovered from the serial data stream. This recovered data needs to be processed by a system clock that is also running at a nominal rate of 125 MHz, but not synchronous to the recovered clock. To cross clock domains, an asynchronous FIFO (first-in-first-out) is used, with the write pointer (wprt) in the recovered clock domain and the read pointer (rptr) in the system clock domain. Because the clocks are generated from separate sources, there is potential for FIFO overflow or underflow. Clock compensation in Gigabit Ethernet is possible by taking advantage of the protocol data stream features. There are two distinct data streams that occur in Gigabit Ethernet where identical data is transmitted for a period of time. The first is configuration, which happens during auto-negotiation. The second is idle, which occurs at the end of auto-negotiation and between every packet. The identical data in the FIFO can be repeated by decrementing the read pointer, thus compensating for a FIFO that is draining too fast. The identical data in the FIFO can also be skipped by incrementing the read pointer, which compensates for a FIFO draining too slowly. The unique and novel features of this FIFO are that it works in both the idle stream and the configuration streams. The increment or decrement of the read pointer is different in the idle and compensation streams to preserve disparity. Another unique feature is that the read pointer to write pointer difference range changes between compensation and idle to minimize FIFO latency during packet transmission.

Duhachek, Jeff

2012-01-01

445

Amplitude- and rise-time-compensated filters  

DOEpatents

An amplitude-compensated rise-time-compensated filter for a pulse time-of-occurrence (TOOC) measurement system is disclosed. The filter converts an input pulse, having the characteristics of random amplitudes and random, non-zero rise times, to a bipolar output pulse wherein the output pulse has a zero-crossing time that is independent of the rise time and amplitude of the input pulse. The filter differentiates the input pulse, along the linear leading edge of the input pulse, and subtracts therefrom a pulse fractionally proportional to the input pulse. The filter of the present invention can use discrete circuit components and avoids the use of delay lines.

Nowlin, Charles H. (Oak Ridge, TN)

1984-01-01

446

Aligning physician compensation with strategic goals.  

PubMed

In 2012, Mayo Clinic Health System (MCHS) had 13 different physician compensation models among its operating units, with most based on productivity metrics. MCHS aimed to transition all physicians to a single compensation model that would facilitate its integration with Mayo Clinic and promote physician engagement with emerging value-based payment models. The new model, which was implemented this past January, incorporates quality metrics, provides physicians with regular reports of their performance, and already has resulted in greater physician attention to outcomes, safety, and patient experience. PMID:25076636

Bunkers, Brian; Koch, Mark; McDonough, Becky; Whited, Brian

2014-07-01

447

Efficient Geolocation of InSAR Images from Motion Compensation Processors  

NASA Astrophysics Data System (ADS)

We present an efficient and closed-form algorithm for the geolocation of InSAR images resulting from data processors using motion compensation methods in which the known orbits are corrected and processed to a circular arc reference track. We outline here a derivation utilizing the SCH coordinate system, although our approach may be readily applied to any such processor with suitable changes in coordinate definitions. Motion compensation has been traditionally employed in airborne systems, where the instability of the aircraft trajectories presents issues in the accuracy of the processed phase. However, we have found that motion compensation techniques allowing precise output pixel location are useful in both airborne and spaceborne systems; thus, we present an approach that exploits the simplicity of a properly chosen motion compensation reference geometry. Assuming a circular reference track, we develop a closed form set of equations relating the position of a given DEM pixel to that of the radar. Once position and slant-range are known along the reference arc, we interpolate into the uniformly spaced radar image, avoiding the use of computationally intensive irregular interpolation algorithms. Hence, the resulting equations are simple and lead to a solution that is remarkably fast without sacrificing precision. We demonstrate results from the ALOS platform, validated against the set of corner reflectors deployed by the Jet Propulsion Laboratory at the Rosamond Calibration Array outside of Palmdale, California. Here we see ground projection errors with accuracy on the order of less than a pixel (< 15 m). In addition, we present an extension to our algorithm where the processed Doppler centroid has known range-dependence but with no simple functional form. To accommodate this most general case, we must replace the closed-form equations with an iterative solution. We illustrate these results using data from the NASA/JPL UAVSAR sensor, where we see fast convergence in no more than five iterations.

Wortham, C.; Zebker, H. A.

2010-12-01

448

Compensation for workplace injury leading to suicide in Australia.  

PubMed

Workplace-related death by suicide raises a number of difficult issues in the context of workers compensation. On first reading, workers compensation statutes usually prevent recovery of compensation where an injury is self-inflicted, suggesting that compensation for suicide will be excluded. Additionally, compensation is usually denied when the nexus between employment and injury is broken which is frequently the defence to any claim by the dependants of workers who takes their own life following a work injury. This article examines the Australian landscape in relation to the evolution of principles that apply to consideration of workers compensation claims where suicide is an element. PMID:21355435

Guthrie, Robert; Westaway, Jennifer

2010-12-01

449

Real-time vibration compensation for large telescopes  

NASA Astrophysics Data System (ADS)

We compare different strategies for minimizing the effects of telescope vibrations to the differential piston (optical pathway difference) for the Near-InfraRed/Visible Adaptive Camera and INterferometer for Astronomy (LINC-NIRVANA) at the Large Binocular Telescope (LBT) using an accelerometer feedforward compensation approach. We summarize, why this technology is important for LINC-NIRVANA, and also for future telescopes and already existing instruments. The main objective is outlining a solution for the estimation problem in general and its specifics at the LBT. Emphasis is put on realistic evaluation of the used algorithms in the laboratory, such that predictions for the expected performance at the LBT can be made. Model-based estimation and broad-band filtering techniques can be used to solve the estimation task, and the differences are discussed. Simulation results and measurements are shown to motivate our choice of the estimation algorithm for LINC-NIRVANA. The laboratory setup is aimed at imitating the vibration behaviour at the LBT in general, and the M2 as main contributor in particular. For our measurements, we introduce a disturbance time series which has a frequency spectrum comparable to what can be measured at the LBT on a typical night. The controllers' ability to suppress vibrations in the critical frequency range of 8-60 Hz is demonstrated. The experimental results are promising, indicating the ability to suppress differential piston induced by telescope vibrations by a factor of about 5 (rms), which is significantly better than any currently commissioned system.

Bhm, M.; Pott, J.-U.; Sawodny, O.; Herbst, T.; Krster, M.

2014-08-01

450

ATMOSPHERIC ~ ~ RESEARCH  

E-print Network

. 1. Introduction Air pollution and acid rain have become the subject of (not only) scientific within the troposphere and the transport of pollutants as well as acid rain even in rural regions the atmosphere by wet deposition. Moreover, the ambient temperature is influ- enced by the phase transitions

Moelders, Nicole

451

Atmospheric Chemistry  

NSDL National Science Digital Library

This set of links provides access to resources on atmospheric chemistry, especially acid deposition, air pollution, and air quality. The sites include personal and government pages, universities and research groups, non-governmental organizations and meetings, and products and services. There are also links to related search topics.

452

Development of homotopy algorithms for fixed-order mixed H2/H(infinity) controller synthesis  

NASA Technical Reports Server (NTRS)

A major difficulty associated with H-infinity and mu-synthesis methods is the order of the resulting compensator. Whereas model and/or controller reduction techniques are sometimes applied, performance and robustness properties are not preserved. By directly constraining compensator order during the optimization process, these properties are better preserved, albeit at the expense of computational complexity. This paper presents a novel homotopy algorithm to synthesize fixed-order mixed H2/H-infinity compensators. Numerical results are presented for a four-disk flexible structure to evaluate the efficiency of the algorithm.

Whorton, M.; Buschek, H.; Calise, A. J.

1994-01-01

453

Smoothing of respiratory motion traces for motion-compensated radiotherapy  

SciTech Connect

Purpose: The CyberKnife system has been used successfully for several years to radiosurgically treat tumors without the need for stereotactic fixation or sedation of the patient. It has been shown that tumor motion in the lung, liver, and pancreas can be tracked with acceptable accuracy and repeatability. However, highly precise targeting for tumors in the lower abdomen, especially for tumors which exhibit strong motion, remains problematic. Reasons for this are manifold, like the slow tracking system operating at 26.5 Hz, and using the signal from the tracking camera ''as is''. Since the motion recorded with the camera is used to compensate for system latency by prediction and the predicted signal is subsequently used to infer the tumor position from a correlation model based on x-ray imaging of gold fiducials around the tumor, camera noise directly influences the targeting accuracy. The goal of this work is to establish the suitability of a new smoothing method for respiratory motion traces used in motion-compensated radiotherapy. The authors endeavor to show that better prediction--With a lower rms error of the predicted signal--and/or smoother prediction is possible using this method. Methods: The authors evaluated six commercially available tracking systems (NDI Aurora, PolarisClassic, Polaris Vicra, MicronTracker2 H40, FP5000, and accuTrack compact). The authors first tracked markers both stationary and while in motion to establish the systems' noise characteristics. Then the authors applied a smoothing method based on the a trous wavelet decomposition to reduce the devices' noise level. Additionally, the smoothed signal of the moving target and a motion trace from actual human respiratory motion were subjected to prediction using the MULIN and the nLMS{sub 2} algorithms. Results: The authors established that the noise distribution for a static target is Gaussian and that when the probe is moved such as to mimic human respiration, it remains Gaussian with the exception of the FP5000 and the Aurora systems. The authors also showed that the proposed smoothing method can indeed be used to filter noise. The signal's jitter dropped by as much as 95% depending on the tracking system employed. Subsequently, the 3D prediction error (rms) for a prediction horizon of 150 ms on a synthetic signal dropped by up to 37% when using a normalized LMS prediction algorithm (nLMS{sub 2}) and hardly changed when using a MULIN algorithm. When smoothing a real signal obtained in our laboratory, the improvement of prediction was similar: Up to 30% for both the nLMS{sub 2} and the best MULIN algorithm. The authors also found a noticeable increase in smoothness of the predicted signal, the relative jitter dropped by up to 95% on the real signal, and on the simulated signal. Conclusions: In conclusion, the authors can say that preprocessing of marker data is very useful in motion-compensated radiotherapy since the quality of prediction increases. This will result in better performance of the correlation model. As a side effect, since the prediction of a preprocessed signal is also less noisy, the authors expect less robot vibration resulting in better targeting accuracy and less strain on the robot gears.

Ernst, Floris; Schlaefer, Alexander; Schweikard, Achim [Institute for Robotics and Cognitive Systems, University of Luebeck, Ratzeburger Allee 160, Luebeck SH 23538 (Germany)

2010-01-15

454

Static VAr compensator with neural network control  

Microsoft Academic Search

Artificial neural networks (ANNs) have been used in many applications of pattern classification, speech synthesis and recognition, function approximation, associative memory and control. Because of their adaptive nature and parallel computational features, they are promising a lot of hope for future of engineering. In this study, an application of ANN in control has been presented. A static VAr compensator model

B. Mumyakmaz; Xianhe Jin; Changchang Wang; T. C. Cheng

1999-01-01

455

Solenoid Valve With Self-Compensation  

NASA Technical Reports Server (NTRS)

New solenoid-operated miniature shutoff valve provides self-compensation of differential pressure forces that cause jamming or insufficient valve closure as in single-seal valves. Dual-seal valve is bidirectional. Valve simultaneously seals both inlet and outlet tubes by pressing single disk of silicone rubber against ends of both.

Woeller, Fritz H.; Matsumoto, Yutaka

1987-01-01

456

Administrative Compensation Survey 1995-96.  

ERIC Educational Resources Information Center

This 19th annual administrative compensation survey is designed to provide the most comprehensive and timely data available for college and university administrators. The benchmarking resource comparison provides comparison salary data for 170 administrative positions, based on responses from 1,384 institutions. The positions include those in

College and Univ. Personnel Association, Washington, DC.

457

Administrative Compensation Survey 1994-95.  

ERIC Educational Resources Information Center

This 18th annual administrative compensation survey is designed to provide the most comprehensive and up-to-date salary data available for college and university administrators. The benchmarking resource provides comparison salary data for 168 administrative positions found in colleges and universities nationwide, based on responses from over

Creal, Richard C.; Beyer, Kirk D.

458

Compensation programs mean more than money.  

PubMed

How do health care and, particularly, home care administrators use incentive programs? What are health care professionals and paraprofessional looking for? Is it money, security, or just meeting the needs of everyday life? What motivators are the key to successful compensation programs? PMID:11436460

Freels, R A

2001-07-01

459

Laser focus compensating sensing and imaging device  

DOEpatents

A laser focus compensating sensing and imaging device permits the focus of a single focal point of different frequency laser beams emanating from the same source point. In particular it allows the focusing of laser beam originating from the same laser device but having differing intensities so that a low intensity beam will not convert to a higher frequency when passing through a conversion crystal associated with the laser generating device. The laser focus compensating sensing and imaging device uses a Cassegrain system to fold the lower frequency, low intensity beam back upon itself so that it will focus at the same focal point as a high intensity beam. An angular tilt compensating lens is mounted about the secondary mirror of the Cassegrain system to assist in alignment. In addition cameras or CCD's are mounted with the primary mirror to sense the focused image. A convex lens is positioned co-axial with the Cassegrain system on the side of the primary mirror distal of the secondary for use in aligning a target with the laser beam. A first alternate embodiment includes a Cassegrain system using a series of shutters and an internally mounted dichroic mirror. A second alternate embodiment uses two laser focus compensating sensing and imaging devices for aligning a moving tool with a work piece.

Vann, C.S.

1993-08-31

460

Chief Executive Compensation and Benefits Survey 1995.  

ERIC Educational Resources Information Center

This report provides data on salaries, benefits, and perquisites commonly included in the total compensation packages available to higher education chief executives, along with data on employment policies and practices. It is based on a survey of 916 institutions representing all segments of higher education. Data are presented in 141 tables under

College and Univ. Personnel Association, Washington, DC.

461

Blind dispersion compensation for optical coherence tomography  

E-print Network

We propose a numerical method for compensating dispersion effects in optical coherence tomography that does not require a priori knowledge of dispersive properties of the sample. The method is based on the generalized autoconvolution function, and its principle of operation can be intuitively visualized using the Wigner distribution function formalism.

Konrad Banaszek; Aleksandr S. Radunsky; Ian A. Walmsley

2004-04-09

462

Administrative Compensation Survey, 1985-86.  

ERIC Educational Resources Information Center

Results of the College and University Personnel Association (CUPA) 1985-86 Administrative Compensation Survey, which provides salary data on 99 first-line (primary) positions and 69 second-line (secondary) positions, are presented. Questionnaires were sent to 2,932 higher education institutions, and 1,612 usable responses were obtained. Salary

Anderson, Shari L.; And Others

463

Dispersion Compensation with a Prism-pair  

E-print Network

We present a detailed calculation of the total dispersion (spectral phase) from a pair of Brewster-cut prisms. This paper aims to aid advanced students in tracking the operation of this major configuration for dispersion-compensation and phase-control of ultra-short pulses.

Shaked, Yaakov; Pe'er, Avi

2014-01-01

464

Connected Companies' Compensation Alexander W. Butler  

E-print Network

, Lee Ann Butler, Lauren Cohen, Wayne Guay, Katherine Guthrie, Erik Lie, David Mauer, Stanimir MarkovConnected Companies' Compensation Alexander W. Butler Umit G. Gurun School of Management University information. Email: Butler butler@utdallas.edu; Gurun umit.gurun@utdallas.edu. Please address

465

Ground layer sensing and compensation Andrei Tokovinin  

E-print Network

is the effect of the partially compensated layers on the PSF. This will eventually determine the image, hence the long-exposure PSF is directly related to the structure function of the phase residuals D (x pitch Altitudes Intensities Ji hi FFT Structure function PSFAO parameters OTF Multiply and add G f

Tokovinin, Andrei A.

466

Subreflectarrays for Reflector Surface Distortion Compensation  

Microsoft Academic Search

With the increasing interest in the applications of large deployable reflector antennas operating at high frequencies, the requirement on the reflector surface accuracy becomes more demanding. Thermal effects inevitably cause certain reflector surface distortions, thus degrading the overall antenna performance. This paper introduces a novel reflector surface distortion compensation technique using a subreflectarray and presents detailed discussions. A microstrip reflectarray

Shenheng Xu; Yahya Rahmat-Samii; William A. Imbriale

2009-01-01

467

Compensation for gradient-based adaptive observers  

Microsoft Academic Search

A method of compensating adaptive observers for actuator noise is proposed. The main idea of the method is to filter the output error and use this filtered signal to adjust the state and parameter estimates of the observer. The error filter can be any system which satisfies certain very general criteria. A simulation is presented in which errors resulting from

John H. Lilly

1996-01-01

468

7 CFR 301.74-5 - Compensation.  

Code of Federal Regulations, 2011 CFR

...compensation for losses associated with the destruction of trees in order to control plum pox pursuant to an...ii) of this section. (2) Owners of fruit tree nurseries. The owner of a fruit tree nursery will be eligible to receive...

2011-01-01

469

7 CFR 301.74-5 - Compensation.  

Code of Federal Regulations, 2014 CFR

...compensation for losses associated with the destruction of trees in order to control plum pox pursuant to an...ii) of this section. (2) Owners of fruit tree nurseries. The owner of a fruit tree nursery will be eligible to receive...

2014-01-01

470

7 CFR 301.74-5 - Compensation.  

Code of Federal Regulations, 2013 CFR

...compensation for losses associated with the destruction of trees in order to control plum pox pursuant to an...ii) of this section. (2) Owners of fruit tree nurseries. The owner of a fruit tree nursery will be eligible to receive...

2013-01-01

471

7 CFR 301.74-5 - Compensation.  

Code of Federal Regulations, 2010 CFR

...compensation for losses associated with the destruction of trees in order to control plum pox pursuant to an...ii) of this section. (2) Owners of fruit tree nurseries. The owner of a fruit tree nursery will be eligible to receive...

2010-01-01

472

7 CFR 301.74-5 - Compensation.  

Code of Federal Regulations, 2012 CFR

...compensation for losses associated with the destruction of trees in order to control plum pox pursuant to an...ii) of this section. (2) Owners of fruit tree nurseries. The owner of a fruit tree nursery will be eligible to receive...

2012-01-01

473

Method for mask repair using defect compensation  

SciTech Connect

A method for repair of amplitude and/or phase defects in lithographic masks. The method involves modifying or altering a portion of the absorber pattern on the surface of the mask blank proximate to the mask defect to compensate for the local disturbance (amplitude or phase) of the optical field due to the defect.

Sweeney, Donald W. (San Ramon, CA); Ray-Chaudhuri, Avijit K. (Livermore, CA)

2001-01-01

474

Compensation Adjustment Request Form EMPLOYEE INFORMATION  

E-print Network

Working Title If applicable Performance Review Score Date Last Review: Percent Last Increase: Date of Last: ________________________________________________________________________________________________________ ________________________________________________________________________________________________________ ________________________________________________________________________________________________________ ________________________________________________________________________________________________________ NOTE: Attach supporting documentation, i.e. performance reviews, position description, careerYes No Yes No Compensation Adjustment Request Form EMPLOYEE INFORMATION Employee Name: Last First

Veiga, Pedro Manuel Barbosa

475

Passive dual spin misalignment compensators. [gyrostabilized device  

NASA Technical Reports Server (NTRS)

A combination dual-spin gyroscopically stabilized device is described having a spinning rotor and a non-spinning platform. Two substantially lossless mechanical resonators, resonant at the spin frequency, are orthogonally positioned on the platform for compensation for the disturbing torque acting on the platform due to rotor misalignment.

Donohue, J. H.; Zimmerman, B. G. (inventors)

1974-01-01

476

HOW MUCH COMPENSATION CAN CEOS PERMISSIBLY ACCEPT?  

Microsoft Academic Search

Debates about the ethics of executive compensation are dominated by familiar themes. Many writers consider whether the amount of pay CEOs receive is too large - relative to firm performance, foreign CEO pay, or employee pay. Many others consider whether the process by which CEOs are paid is compromised by weak or self-serving boards of directors. This paper examines the

Jeffrey Moriarty

477

Workers' Compensation Program Review and Approval Authority  

E-print Network

, the employee shall comply with a request for a medical evaluation. #12;2 Workers' CompenJuly 2003 #12;Workers' Compensation Program Review and Approval Authority Prepared and Edited by Date Reviewed and Approved by: Chair - UM E, H & S Operations Committee Date Chair - UM E, H & S Policy

Rubloff, Gary W.

478

Flywheels Would Compensate for Rotor Imbalance  

NASA Technical Reports Server (NTRS)

Spinning flywheels within rotor can null imbalance forces in rotor. Flywheels axes are perpendicular to each other and to rotor axis. Feedback signals from accelerometers or strain gages in platform control flywheel speeds and rotation directions. Concept should be useful for compensating rotating bodies on Earth. For example, may be applied to large industrial centrifuge, particularly if balance changes during operation.

Hrastar, J. A. S.

1982-01-01

479

Racial Differences in Professional Basketball Players' Compensation  

Microsoft Academic Search

This article investigates racial differences in 1985-86 salaries of individual professio nal basketball players. White and black players earn similar mean com pensation; however, controlling for a variety of productivity and mar ket-related variables and for the endogeneity of player draft positio n, the authors find a significant ceteris paribus black compensation shortfall of about 20 percent. Further, they find

Lawrence M. Kahn; Peter D. Sherer

1988-01-01

480

Improving multiresolution motion compensating hybrid coding  

E-print Network

dis­ play (e.g. HDTV, TV) in case of transmission errors. In general, multiresolution source codingImproving multiresolution motion compensating hybrid coding by drift reduction Ulrich Benzler­ pensation is evaluated for the base layer performance in a multiresolution hybrid coding scheme. At constant

481

77 FR 5381 - Plum Pox Compensation  

Federal Register 2010, 2011, 2012, 2013, 2014

...orchards, including direct marketers, and fruit tree nurseries...compensation played an important role in the successful eradication...stone fruit growers and direct marketers and in fruit tree nurseries...experienced by grove owners, direct marketers, and nursery owners who...

2012-02-03

482

About HR Compensation Employee Retirement and  

E-print Network

Development Job Descriptions Training Prospective Employees Employment Opportunities eJobs for Applicants e Center Web Page ETSU Retirees Association Web Page Employee Development Center Online Training SupportHOME About HR Compensation Employment Employee Retirement and Benefits Employee Relations Employee

Karsai, Istvan

483

Temperature compensation for optical current sensors  

Microsoft Academic Search

An analysis of an optical current transducer (OCT) considering in particular the influence of temperature induced variations in the Verdet constant is presented. The analysis is supported by an experimental evaluation of a prototype OCT over a range of operating temperatures and current values and concludes with a laboratory demonstration of a temperature compensation scheme that improves the measurement precision

W. Iain Madden; W. Craig Michie; Andrew Cruden; Pawel Niewczas; J. R. McDonald; Ivan Andonovic

1999-01-01