Science.gov

Sample records for preliminary performance estimates

  1. Estimating Basic Preliminary Design Performances of Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Luz, Paul L.; Alexander, Reginald

    2004-01-01

    Aerodynamics and Performance Estimation Toolset is a collection of four software programs for rapidly estimating the preliminary design performance of aerospace vehicles represented by doing simplified calculations based on ballistic trajectories, the ideal rocket equation, and supersonic wedges through standard atmosphere. The program consists of a set of Microsoft Excel worksheet subprograms. The input and output data are presented in a user-friendly format, and calculations are performed rapidly enough that the user can iterate among different trajectories and/or shapes to perform "what-if" studies. Estimates that can be computed by these programs include: 1. Ballistic trajectories as a function of departure angles, initial velocities, initial positions, and target altitudes; assuming point masses and no atmosphere. The program plots the trajectory in two-dimensions and outputs the position, pitch, and velocity along the trajectory. 2. The "Rocket Equation" program calculates and plots the trade space for a vehicle s propellant mass fraction over a range of specific impulse and mission velocity values, propellant mass fractions as functions of specific impulses and velocities. 3. "Standard Atmosphere" will estimate the temperature, speed of sound, pressure, and air density as a function of altitude in a standard atmosphere, properties of a standard atmosphere as functions of altitude. 4. "Supersonic Wedges" will calculate the free-stream, normal-shock, oblique-shock, and isentropic flow properties for a wedge-shaped body flying supersonically through a standard atmosphere. It will also calculate the maximum angle for which a shock remains attached, and the minimum Mach number for which a shock becomes attached, all as functions of the wedge angle, altitude, and Mach number.

  2. A preliminary comparison of different methods for observer performance estimation

    NASA Astrophysics Data System (ADS)

    Massanes, Francesc; Brankov, Jovan G.

    2013-03-01

    In medical imaging, image quality is assessed by the degree to which a human observer can correctly perform a given diagnostic task. Therefore the image quality is typically quantified by using performance measurements from decision/detection theory like the receiver operation characteristic (ROC) curve and the area under ROC curve (AUC). In this paper we compare five different AUC estimation techniques, widely used in the literature, including parametric and non-parametric methods. We compared each method by equivalence hypothesis testing using a model observer as well as data sets from a previously published human observer study. The main conclusions of this work are 1) if a small number of images are scored, one cannot tell apart different AUC estimation methods due to large variability in AUC estimates, regardless whether image scores are reported on a continuous or quantized scale. 2) If the number of scored images is large and image scores are reported on a continuous scale, all tested AUC estimation methods are statistically equivalent.

  3. PRELIMINARY PERFORMANCE AND COST ESTIMATES OF MERCURY EMISSION CONTROL OPTIONS FOR ELECTRIC UTILITY BOILERS

    EPA Science Inventory


    The paper discusses preliminary performance and cost estimates of mercury emission control options for electric utility boilers. Under the Clean Air Act Amendments of 1990, EPA had to determine whether mercury emissions from coal-fired power plants should be regulated. To a...

  4. PRELIMINARY PERFORMANCE AND COST ESTIMATES OF MERCURY EMISSION CONTROL OPTIONS FOR ELECTRIC UTILITY BOILERS

    EPA Science Inventory


    The paper discusses preliminary performance and cost estimates of mercury emission control options for electric utility boilers. Under the Clean Air Act Amendments of 1990, EPA had to determine whether mercury emissions from coal-fired power plants should be regulated. To a...

  5. PRELIMINARY ESTIMATES OF PERFORMANCE AND COST OF MERCURY CONTROL TECHNOLOGY APPLICATIONS ON ELECTRIC UTILITY BOILERS

    EPA Science Inventory

    Under the Clean Air Act Amendments of 1990, the Environmental Protection Agency has determined that regulation of mercury emissions from coal-fired power plants is appropriate and necessary. To aid in this determination, preliminary estimates of the performance and cost of powder...

  6. PRELIMINARY ESTIMATES OF PERFORMANCE AND COST OF MERCURY CONTROL TECHNOLOGY APPLICATIONS ON ELECTRIC UTILITY BOILERS

    EPA Science Inventory

    Under the Clean Air Act Amendments of 1990, the Environmental Protection Agency has determined that regulation of mercury emissions from coal-fired power plants is appropriate and necessary. To aid in this determination, preliminary estimates of the performance and cost of powder...

  7. Preliminary Estimates of Performance and Cost of Mercury Control Technology Applications on Electric Utility Boilers.

    PubMed

    Srivastava, Ravi K; Sedman, Charles B; Kilgroe, James D; Smith, Dennis; Renninger, Scott

    2001-10-01

    Under the Clean Air Act Amendments of 1990, the U.S. Environmental Protection Agency (EPA) determined that regulation of mercury emissions from coal-fired power plants is appropriate and necessary. To aid in this determination, preliminary estimates of the performance and cost of powdered activated carbon (PAC) injection-based mercury control technologies were developed. This paper presents these estimates and develops projections of costs for future applications. Cost estimates were developed using PAC to achieve a minimum of 80% mercury removal at plants using electrostatic precipitators and a minimum of 90% removal at plants using fabric filters. These estimates ranged from 0.305 to 3.783 mills/kWh. However, the higher costs were associated with a minority of plants using hot-side electrostatic precipitators (HESPs). If these costs are excluded, the estimates range from 0.305 to 1.915 mills/kWh. Cost projections developed using a composite lime-PAC sorbent for mercury removal ranged from 0.183 to 2.270 mills/kWh, with the higher costs being associated with a minority of plants that used HESPs.

  8. Preliminary estimates of performance and cost of mercury control technology applications on electric utility boilers.

    PubMed

    Srivastava, R K; Sedman, C B; Kilgroe, J D; Smith, D; Renninger, S

    2001-10-01

    Under the Clean Air Act Amendments of 1990, the U.S. Environmental Protection Agency (EPA) determined that regulation of mercury emissions from coal-fired power plants is appropriate and necessary. To aid in this determination, preliminary estimates of the performance and cost of powdered activated carbon (PAC) injection-based mercury control technologies were developed. This paper presents these estimates and develops projections of costs for future applications. Cost estimates were developed using PAC to achieve a minimum of 80% mercury removal at plants using electrostatic precipitators and a minimum of 90% removal at plants using fabric filters. These estimates ranged from 0.305 to 3.783 mills/kWh. However, the higher costs were associated with a minority of plants using hot-side electrostatic precipitators (HESPs). If these costs are excluded, the estimates range from 0.305 to 1.915 mills/kWh. Cost projections developed using a composite lime-PAC sorbent for mercury removal ranged from 0.183 to 2.270 mills/kWh, with the higher costs being associated with a minority of plants that used HESPs.

  9. Preliminary Estimates of Performance and Cost of Mercury Control Technology Applications on Electric Utility Boilers.

    PubMed

    Srivastava, Ravi K; Sedman, Charles B; Kilgroe, James D; Smith, Dennis; Renninger, Scott

    2001-10-01

    Under the Clean Air Act Amendments of 1990, the U.S. Environmental Protection Agency (EPA) determined that regulation of mercury emissions from coal-fired power plants is appropriate and necessary. To aid in this determination, preliminary estimates of the performance and cost of powdered activated carbon (PAC) injection-based mercury control technologies were developed. This paper presents these estimates and develops projections of costs for future applications. Cost estimates were developed using PAC to achieve a minimum of 80% mercury removal at plants using electrostatic precipitators and a minimum of 90% removal at plants using fabric filters. These estimates ranged from 0.305 to 3.783 mills/kWh. However, the higher costs were associated with a minority of plants using hot-side electrostatic precipitators (HESPs). If these costs are excluded, the estimates range from 0.305 to 1.915 mills/kWh. Cost projections developed using a composite lime-PAC sor-bent for mercury removal ranged from 0.183 to 2.270 mills/kWh, with the higher costs being associated with a minority of plants that used HESPs.

  10. Smarter Balanced Preliminary Performance Levels: Estimated MAP Scores Corresponding to the Preliminary Performance Levels of the Smarter Balanced Assessment Consortium (Smarter Balanced)

    ERIC Educational Resources Information Center

    Northwest Evaluation Association, 2015

    2015-01-01

    Recently, the Smarter Balanced Assessment Consortium (Smarter Balanced) released a document that established initial performance levels and the associated threshold scale scores for the Smarter Balanced assessment. The report included estimated percentages of students expected to perform at each of the four performance levels, reported by grade…

  11. Preliminary estimates of performance and cost of mercury emission control technology applications on electric utility boilers: An update

    SciTech Connect

    Srivastava, R.K.; Staudt, J.E.; Jozewicz, W.

    2005-07-01

    The Environmental Protection Agency has recently proposed a reduction in mercury emissions from coal-fired power plants. There are two broad approaches under development to controlling mercury emissions from coal-fired electric utility boilers. (1) powdered activated carbon (PAC) injection; and (2) multipollutant control, in which Hg capture is enhanced in existing and new sulfur dioxide (SO{sub 2}), nitrogen oxides (NOx), and particulate matter (PM) control devices. To help inform the recent EPA rulemaking proposal, estimates of performance levels and related costs associated with the above mercury control approaches were developed. This work presents these estimates. Estimates of cost for PAC injection range from 0.003 to 3.096 mills/kWb. In general, the higher costs are associated with the plants using spray dryers and electrostatic precipitators (ESPs) or plants using hot-side ESPs, which represent a minority of power plants. Excluding these plants, cost estimates range between 0.003 and 1.903 mills/kWh. At the low end of the cost ranges, 0.003 mills/kWb, it is assumed that no additional control technologies are needed, but mercury monitoring will be necessary. In these cases, high mercury removal may be the result of the type of NOx and SO{sub 2} control measures currently used, such as combinations of selective catalytic reduction and wet flue gas desulfurization or spray drier absorbers with fabric filters on bituminous coal-fired boilers. Because mercury control approaches are under development at present, cost and performance estimates are preliminary and are expected to be refined as mercury control technologies are matured to commercial status. Factors that may affect the performance of these technologies include speciation of mercury in flue gas, the characteristics of the sorbent, and the type(s) of PM, NOx, and SO, controls used.

  12. Preliminary performance estimates of binary geothermal cycles using mixed-halocarbon working fluids

    SciTech Connect

    Bliem, C.J.

    1986-07-01

    The performance of Rankine cycle binary systems for power generation using a hydrothermal resource has been investigated as a part of the DOE/GTD Heat Cycle Research Program. To date mixtures of paraffin-type hydrocarbons and water-ammonia mixtures have been investigated. This report gives the first results of the consideration of mixtures of halocarbons as working fluids in these power cycles. The performance of mixtures of Refrigerant-114 (R-114) and Refrigerant-22 (R-22) in combinations from pure R-114 to pure R-22 was calculated for such cycles. Various alternatives were considered: (1) minimum geofluid outlet temperature constraint/no constraint, (2) dry turbine expansion/expansion through vapor dome, (3) use of a turbine exhaust gas recuperator/no recuperator. Results of the study indicate that the halocarbon mixtures are at least as good as the hydrocarbon mixtures previously analyzed for a 360/sup 0/F resource. The magnitude of the net geofluid effectiveness (net energy produced per unit mass geofluid flow) for the R-114/R-22 mixtures is the same as for the best hydrocarbon mixtures previously analyzed. The percentage improvement in effectiveness in using mixtures over using the pure fluids as working fluids is comparable for both classes of working fluids. Recommendations are made to continue investigation of the halocarbon mixtures as possible alternatives to the hydrocarbon working fluids.

  13. PRELIMINARY ESTIMATES OF PERFORMANCE AND COST OF MERCURY EMISSION CONTROL TECHNOLOGY APPLICATIONS ON ELECTRIC UTILITY BOILERS: AN UPDATE

    EPA Science Inventory

    The paper presents estimates of performance levels and related costs associated with controlling mercury (Hg) emissions from coal-fired power plants using either powdered activated carbon (PAC) injection or multipollutant control in which Hg capture is enhanced in existing and ne...

  14. Preliminary performance estimates of an oblique, all-wing, remotely piloted vehicle for air-to-air combat

    NASA Technical Reports Server (NTRS)

    Nelms, W. P., Jr.; Bailey, R. O.

    1974-01-01

    A computerized aircraft synthesis program has been used to assess the effects of various vehicle and mission parameters on the performance of an oblique, all-wing, remotely piloted vehicle (RPV) for the highly maneuverable, air-to-air combat role. The study mission consists of an outbound cruise, an acceleration phase, a series of subsonic and supersonic turns, and a return cruise. The results are presented in terms of both the required vehicle weight to accomplish this mission and the combat effectiveness as measured by turning and acceleration capability. This report describes the synthesis program, the mission, the vehicle, and results from sensitivity studies. An optimization process has been used to establish the nominal RPV configuration of the oblique, all-wing concept for the specified mission. In comparison to a previously studied conventional wing-body canard design for the same mission, this oblique, all-wing nominal vehicle is lighter in weight and has higher performance.

  15. Formative Evaluation: Estimating Preliminary Outcomes and Testing Rival Explanations

    ERIC Educational Resources Information Center

    Henry, Gary T.; Smith, Adrienne A.; Kershaw, David C.; Zulli, Rebecca A.

    2013-01-01

    Performance-based accountability along with budget tightening has increased pressure on publicly funded organizations to develop and deliver programs that produce meaningful social benefits. As a result, there is increasing need to undertake formative evaluations that estimate preliminary program outcomes and identify promising program components…

  16. TRAC performance estimates

    NASA Technical Reports Server (NTRS)

    Everett, L.

    1992-01-01

    This report documents the performance characteristics of a Targeting Reflective Alignment Concept (TRAC) sensor. The performance will be documented for both short and long ranges. For long ranges, the sensor is used without the flat mirror attached to the target. To better understand the capabilities of the TRAC based sensors, an engineering model is required. The model can be used to better design the system for a particular application. This is necessary because there are many interrelated design variables in application. These include lense parameters, camera, and target configuration. The report presents first an analytical development of the performance, and second an experimental verification of the equations. In the analytical presentation it is assumed that the best vision resolution is a single pixel element. The experimental results suggest however that the resolution is better than 1 pixel. Hence the analytical results should be considered worst case conditions. The report also discusses advantages and limitations of the TRAC sensor in light of the performance estimates. Finally the report discusses potential improvements.

  17. Preliminary melter performance assessment report

    SciTech Connect

    Elliott, M.L.; Eyler, L.L.; Mahoney, L.A.; Cooper, M.F.; Whitney, L.D.; Shafer, P.J.

    1994-08-01

    The Melter Performance Assessment activity, a component of the Pacific Northwest Laboratory`s (PNL) Vitrification Technology Development (PVTD) effort, was designed to determine the impact of noble metals on the operational life of the reference Hanford Waste Vitrification Plant (HWVP) melter. The melter performance assessment consisted of several activities, including a literature review of all work done with noble metals in glass, gradient furnace testing to study the behavior of noble metals during the melting process, research-scale and engineering-scale melter testing to evaluate effects of noble metals on melter operation, and computer modeling that used the experimental data to predict effects of noble metals on the full-scale melter. Feed used in these tests simulated neutralized current acid waste (NCAW) feed. This report summarizes the results of the melter performance assessment and predicts the lifetime of the HWVP melter. It should be noted that this work was conducted before the recent Tri-Party Agreement changes, so the reference melter referred to here is the Defense Waste Processing Facility (DWPF) melter design.

  18. Estimating State IQ: Measurement Challenges and Preliminary Correlates

    ERIC Educational Resources Information Center

    McDaniel, Michael A.

    2006-01-01

    The purpose of this study is threefold. First, an estimate of state IQ is derived and its strengths and limitations are considered. To that end, an indicator of downward bias in estimating state IQ is provided. Two preliminary causal models are offered that predict state IQ. These models were found to be highly predictive of state IQ, yielding…

  19. Satellite servicing mission preliminary cost estimation model

    NASA Technical Reports Server (NTRS)

    1987-01-01

    The cost model presented is a preliminary methodology for determining a rough order-of-magnitude cost for implementing a satellite servicing mission. Mission implementation, in this context, encompassess all activities associated with mission design and planning, including both flight and ground crew training and systems integration (payload processing) of servicing hardward with the Shuttle. A basic assumption made in developing this cost model is that a generic set of servicing hardware was developed and flight tested, is inventoried, and is maintained by NASA. This implies that all hardware physical and functional interfaces are well known and therefore recurring CITE testing is not required. The development of the cost model algorithms and examples of their use are discussed.

  20. Preliminary estimates of radiosonde thermistor errors

    NASA Technical Reports Server (NTRS)

    Schmidlin, F. J.; Luers, J. K.; Huffman, P. D.

    1986-01-01

    Radiosonde temperature measurements are subject to errors, not the least of which is the effect of long- and short-wave radiation. Methods of adjusting the daytime temperatures to a nighttime equivalent are used by some analysis centers. Other than providing consistent observations for analysis this procedure does not provide a true correction. The literature discusses the problem of radiosonde temperature errors but it is not apparent what effort, if any, has been taken to quantify these errors. To accomplish the latter, radiosondes containing multiple thermistors with different coatings were flown at Goddard Space Flight Center/Wallops Flight Facility. The coatings employed had different spectral characteristics and, therefore, different adsorption and emissivity properties. Discrimination of the recorded temperatures enabled day and night correction values to be determined for the US standard white-coated rod thermistor. The correction magnitudes are given and a comparison of US measured temperatures before and after correction are compared with temperatures measured with the Vaisala radiosonde. The corrections are in the proper direction, day and night, and reduce day-night temperature differences to less than 0.5 C between surface and 30 hPa. The present uncorrected temperatures used with the Viz radiosonde have day-night differences that exceed 1 C at levels below 90 hPa. Additional measurements are planned to confirm these preliminary results and determine the solar elevation angle effect on the corrections. The technique used to obtain the corrections may also be used to recover a true absolute value and might be considered a valuable contribution to the meteorological community for use as a reference instrument.

  1. Preliminary performance estimates of a highly maneuverable remotely piloted vehicle. [computerized synthesis program to assess effects of vehicle and mission parameters

    NASA Technical Reports Server (NTRS)

    Nelms, W. P., Jr.; Axelson, J. A.

    1974-01-01

    A computerized synthesis program has been used to assess the effects of various vehicle and mission parameters on the performance of a highly maneuverable remotely piloted vehicle (RPV) for the air-to-air combat role. The configuration used in the study is a trapezoidal-wing and body concept, with forward-mounted stabilizing and control surfaces. The study mission consists of an outbound cruise, an acceleration phase, a series of subsonic and supersonic turns, and a return cruise. Performance is evaluated in terms of both the required vehicle weight to accomplish this mission and combat effectiveness as measured by turning and acceleration capability. The report describes the synthesis program, the mission, the vehicle, and the results of sensitivity and trade studies.

  2. IBIS detector performance during calibration - preliminary analysis

    NASA Astrophysics Data System (ADS)

    Bazzano, A.; Bird, A. J.; Laurent, P.; Malaguti, G.; Quadrini, E. M.; Segreto, A.; Volkmer, R.; del Santo, M.; Gabriele, M.; Tikkanen, T.

    2003-11-01

    The IBIS telescope is a high angular resolution gamma-ray imager due to be launched on the INTEGRAL satellite on October 17, 2002. The scientific goal of IBIS is to study astrophysical processes from celestial sources and diffuse regions in the hard X-ray and soft gamma-ray domains. IBIS features a coded aperture imaging system and a novel large area (~3000cm2) multilayer pixellated detector which utilises both cadmium telluride (16,384 detectors) and caesium iodide elements (4096 detectors) surrounded by a BGO active veto shield. We present an overview of, and preliminary analysis from, the IBIS calibration campaign. The performance of each pixel has been characterised, and hence the scientific performance of the IBIS detector system as a whole can now be established.

  3. Guidance for performing preliminary assessments under CERCLA

    SciTech Connect

    1991-09-01

    EPA headquarters and a national site assessment workgroup produced this guidance for Regional, State, and contractor staff who manage or perform preliminary assessments (PAs). EPA has focused this guidance on the types of sites and site conditions most commonly encountered. The PA approach described in this guidance is generally applicable to a wide variety of sites. However, because of the variability among sites, the amount of information available, and the level of investigative effort required, it is not possible to provide guidance that is equally applicable to all sites. PA investigators should recognize this and be aware that variation from this guidance may be necessary for some sites, particularly for PAs performed at Federal facilities, PAs conducted under EPA`s Environmental Priorities Initiative (EPI), and PAs at sites that have previously been extensively investigated by EPA or others. The purpose of this guidance is to provide instructions for conducting a PA and reporting results. This guidance discusses the information required to evaluate a site and how to obtain it, how to score a site, and reporting requirements. This document also provides guidelines and instruction on PA evaluation, scoring, and the use of standard PA scoresheets. The overall goal of this guidance is to assist PA investigators in conducting high-quality assessments that result in correct site screening or further action recommendations on a nationally consistent basis.

  4. Preliminary basic performance analysis of the Cedar multiprocessor memory system

    NASA Technical Reports Server (NTRS)

    Gallivan, K.; Jalby, W.; Turner, S.; Veidenbaum, A.; Wijshoff, H.

    1991-01-01

    Some preliminary basic results on the performance of the Cedar multiprocessor memory system are presented. Empirical results are presented and used to calibrate a memory system simulator which is then used to discuss the scalability of the system.

  5. Preliminary Helicopter Design Decision Making Based on Flight Performance Factors.

    DTIC Science & Technology

    1984-09-01

    7 AD-Aib 488 PRELIMINRY HELICOPTER DESIGN DECISION MKING BSED ON i’.. FLIGHT PERFORMAiNCE FACTOR (U) NAiVAL POSTGRADUATE SCHOOLMONTEREY CA P Y ADAMCIK...California II 00 THESIS PRELIMINARY HELICOPTER DESIGN DECISION MAKING BASED ON FLIGHT PERFORMANCE FACTORS by liELECTE D Patrick V. Adamcik LJ September 1984...TITLE (end Subtite) 5. TYPE OF REPORT & PERIOD COVERED Preliminary Helicopter Design Decision Master’s Thesis Making Based on Flight Performance

  6. ATR Performance Estimation Seed Program

    DTIC Science & Technology

    2015-09-28

    for this collec ion of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data ...sources, gathering and maintaining the data needed, and completing and reviewing the collec ion of information. Send comments regarding this burden...to produce simulated MCM sonar data and demonstrate the impact of system, environmental, and target scattering effects on ATR detection

  7. Preliminary estimate of undiscovered petroleum resources of southern Africa

    SciTech Connect

    Kingston, J.

    1986-05-01

    Onshore and offshore southern Africa (Nigeria and southward) are ten major rifted continental margin basis; six include about 100,000 mi/sup 2/ on the Atlantic coast, and five encompass about 300,000 mi/sup 2/ on the south and Indian Ocean side, including Madagascar. A series of four very large (totaling about 575,000 mi/sup 2/) interior sag basins are found between South Africa and the central Congo. The Atlantic margin basins are the most prospective and the only ones presently producing. Of these, the Niger delta is by far the most prolific, having original oil and gas reserves of some 25 billion BOE (barrels of oil equivalent) versus five billion BOE for the rest of the basinal trend. The Indian Ocean marginal basins have more area and some shows, including a 22 billion BOE tar sand in Madagascar, but the lack of exploration success downgrades the prospects of this trend. The interior sags have a large volume of sediment; about one-third is marine or lacustrine and probably thermally mature, but lack of established traps, or in some cases sufficient rock, makes for high-risk prospects. Preliminary most-likely estimates of undiscovered oil and gas resources are 15 billion BOE on the Atlantic margin, about 3 billion BOE on the Indian Ocean side, and about 1 billion BOE in the interior sags, with these latter basins having the highest potential for unknown giant fields.

  8. Optimized tuner selection for engine performance estimation

    NASA Technical Reports Server (NTRS)

    Simon, Donald L. (Inventor); Garg, Sanjay (Inventor)

    2013-01-01

    A methodology for minimizing the error in on-line Kalman filter-based aircraft engine performance estimation applications is presented. This technique specifically addresses the underdetermined estimation problem, where there are more unknown parameters than available sensor measurements. A systematic approach is applied to produce a model tuning parameter vector of appropriate dimension to enable estimation by a Kalman filter, while minimizing the estimation error in the parameters of interest. Tuning parameter selection is performed using a multi-variable iterative search routine which seeks to minimize the theoretical mean-squared estimation error. Theoretical Kalman filter estimation error bias and variance values are derived at steady-state operating conditions, and the tuner selection routine is applied to minimize these values. The new methodology yields an improvement in on-line engine performance estimation accuracy.

  9. Biofeedback and dance performance: a preliminary investigation.

    PubMed

    Raymond, Joshua; Sajid, Imran; Parkinson, Lesley A; Gruzelier, John H

    2005-03-01

    Alpha-theta neurofeedback has been shown to produce professionally significant performance improvements in music students. The present study aimed to extend this work to a different performing art and compare alpha-theta neurofeedback with another form of biofeedback: heart rate variability (HRV) biofeedback. Twenty-four ballroom and Latin dancers were randomly allocated to three groups, one receiving neurofeedback, one HRV biofeedback and one no intervention. Dance was assessed before and after training. Performance improvements were found in the biofeedback groups but not in the control group. Neurofeedback and HRV biofeedback benefited performance in different ways. A replication with larger sample sizes is required.

  10. Application of Boosting Regression Trees to Preliminary Cost Estimation in Building Construction Projects.

    PubMed

    Shin, Yoonseok

    2015-01-01

    Among the recent data mining techniques available, the boosting approach has attracted a great deal of attention because of its effective learning algorithm and strong boundaries in terms of its generalization performance. However, the boosting approach has yet to be used in regression problems within the construction domain, including cost estimations, but has been actively utilized in other domains. Therefore, a boosting regression tree (BRT) is applied to cost estimations at the early stage of a construction project to examine the applicability of the boosting approach to a regression problem within the construction domain. To evaluate the performance of the BRT model, its performance was compared with that of a neural network (NN) model, which has been proven to have a high performance in cost estimation domains. The BRT model has shown results similar to those of NN model using 234 actual cost datasets of a building construction project. In addition, the BRT model can provide additional information such as the importance plot and structure model, which can support estimators in comprehending the decision making process. Consequently, the boosting approach has potential applicability in preliminary cost estimations in a building construction project.

  11. Application of Boosting Regression Trees to Preliminary Cost Estimation in Building Construction Projects

    PubMed Central

    2015-01-01

    Among the recent data mining techniques available, the boosting approach has attracted a great deal of attention because of its effective learning algorithm and strong boundaries in terms of its generalization performance. However, the boosting approach has yet to be used in regression problems within the construction domain, including cost estimations, but has been actively utilized in other domains. Therefore, a boosting regression tree (BRT) is applied to cost estimations at the early stage of a construction project to examine the applicability of the boosting approach to a regression problem within the construction domain. To evaluate the performance of the BRT model, its performance was compared with that of a neural network (NN) model, which has been proven to have a high performance in cost estimation domains. The BRT model has shown results similar to those of NN model using 234 actual cost datasets of a building construction project. In addition, the BRT model can provide additional information such as the importance plot and structure model, which can support estimators in comprehending the decision making process. Consequently, the boosting approach has potential applicability in preliminary cost estimations in a building construction project. PMID:26339227

  12. Experiments, conceptual design, preliminary cost estimates and schedules for an underground research facility

    SciTech Connect

    Korbin, G.; Wollenberg, H.; Wilson, C.; Strisower, B.; Chan, T.; Wedge, D.

    1981-09-01

    Plans for an underground research facility are presented, incorporating techniques to assess the hydrological and thermomechanical response of a rock mass to the introduction and long-term isolation of radioactive waste, and to assess the effects of excavation on the hydrologic integrity of a repository and its subsequent backfill, plugging, and sealing. The project is designed to utilize existing mine or civil works for access to experimental areas and is estimated to last 8 years at a total cost for contruction and operation of $39.0 million (1981 dollars). Performing the same experiments in an existing underground research facility would reduce the duration to 7-1/2 years and cost $27.7 million as a lower-bound estimate. These preliminary plans and estimates should be revised after specific sites are identified which would accommodate the facility.

  13. A Preliminary Foil Gas Bearing Performance Map

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Radil, Kevin C.; Bruckner, Robert J.; Howard, S. Adam

    2006-01-01

    Recent breakthrough improvements in foil gas bearing load capacity, high temperature tribological coatings and computer based modeling have enabled the development of increasingly larger and more advanced Oil-Free Turbomachinery systems. Successful integration of foil gas bearings into turbomachinery requires a step wise approach that includes conceptual design and feasibility studies, bearing testing, and rotor testing prior to full scale system level demonstrations. Unfortunately, the current level of understanding of foil gas bearings and especially their tribological behavior is often insufficient to avoid developmental problems thereby hampering commercialization of new applications. In this paper, a new approach loosely based upon accepted hydrodynamic theory, is developed which results in a "Foil Gas Bearing Performance Map" to guide the integration process. This performance map, which resembles a Stribeck curve for bearing friction, is useful in describing bearing operating regimes, performance safety margins, the effects of load on performance and limiting factors for foil gas bearings.

  14. Assessing the performance of dynamical trajectory estimates

    NASA Astrophysics Data System (ADS)

    Bröcker, Jochen

    2014-06-01

    Estimating trajectories and parameters of dynamical systems from observations is a problem frequently encountered in various branches of science; geophysicists for example refer to this problem as data assimilation. Unlike as in estimation problems with exchangeable observations, in data assimilation the observations cannot easily be divided into separate sets for estimation and validation; this creates serious problems, since simply using the same observations for estimation and validation might result in overly optimistic performance assessments. To circumvent this problem, a result is presented which allows us to estimate this optimism, thus allowing for a more realistic performance assessment in data assimilation. The presented approach becomes particularly simple for data assimilation methods employing a linear error feedback (such as synchronization schemes, nudging, incremental 3DVAR and 4DVar, and various Kalman filter approaches). Numerical examples considering a high gain observer confirm the theory.

  15. Assessing the performance of dynamical trajectory estimates.

    PubMed

    Bröcker, Jochen

    2014-06-01

    Estimating trajectories and parameters of dynamical systems from observations is a problem frequently encountered in various branches of science; geophysicists for example refer to this problem as data assimilation. Unlike as in estimation problems with exchangeable observations, in data assimilation the observations cannot easily be divided into separate sets for estimation and validation; this creates serious problems, since simply using the same observations for estimation and validation might result in overly optimistic performance assessments. To circumvent this problem, a result is presented which allows us to estimate this optimism, thus allowing for a more realistic performance assessment in data assimilation. The presented approach becomes particularly simple for data assimilation methods employing a linear error feedback (such as synchronization schemes, nudging, incremental 3DVAR and 4DVar, and various Kalman filter approaches). Numerical examples considering a high gain observer confirm the theory.

  16. Star Tracker Performance Estimate with IMU

    NASA Technical Reports Server (NTRS)

    Aretskin-Hariton, Eliot D.; Swank, Aaron J.

    2015-01-01

    A software tool for estimating cross-boresight error of a star tracker combined with an inertial measurement unit (IMU) was developed to support trade studies for the Integrated Radio and Optical Communication project (iROC) at the National Aeronautics and Space Administration Glenn Research Center. Typical laser communication systems, such as the Lunar Laser Communication Demonstration (LLCD) and the Laser Communication Relay Demonstration (LCRD), use a beacon to locate ground stations. iROC is investigating the use of beaconless precision laser pointing to enable laser communication at Mars orbits and beyond. Precision attitude knowledge is essential to the iROC mission to enable high-speed steering of the optical link. The preliminary concept to achieve this precision attitude knowledge is to use star trackers combined with an IMU. The Star Tracker Accuracy (STAcc) software was developed to rapidly assess the capabilities of star tracker and IMU configurations. STAcc determines the overall cross-boresight error of a star tracker with an IMU given the characteristic parameters: quantum efficiency, aperture, apparent star magnitude, exposure time, field of view, photon spread, detector pixels, spacecraft slew rate, maximum stars used for quaternion estimation, and IMU angular random walk. This paper discusses the supporting theory used to construct STAcc, verification of the program and sample results.

  17. Safety Performance of Airborne Separation: Preliminary Baseline Testing

    NASA Technical Reports Server (NTRS)

    Consiglio, Maria C.; Hoadley, Sherwood T.; Wing, David J.; Baxley, Brian T.

    2007-01-01

    The Safety Performance of Airborne Separation (SPAS) study is a suite of Monte Carlo simulation experiments designed to analyze and quantify safety behavior of airborne separation. This paper presents results of preliminary baseline testing. The preliminary baseline scenario is designed to be very challenging, consisting of randomized routes in generic high-density airspace in which all aircraft are constrained to the same flight level. Sustained traffic density is varied from approximately 3 to 15 aircraft per 10,000 square miles, approximating up to about 5 times today s traffic density in a typical sector. Research at high traffic densities and at multiple flight levels are planned within the next two years. Basic safety metrics for aircraft separation are collected and analyzed. During the progression of experiments, various errors, uncertainties, delays, and other variables potentially impacting system safety will be incrementally introduced to analyze the effect on safety of the individual factors as well as their interaction and collective effect. In this paper we report the results of the first experiment that addresses the preliminary baseline condition tested over a range of traffic densities. Early results at five times the typical traffic density in today s NAS indicate that, under the assumptions of this study, airborne separation can be safely performed. In addition, we report on initial observations from an exploration of four additional factors tested at a single traffic density: broadcast surveillance signal interference, extent of intent sharing, pilot delay, and wind prediction error.

  18. Preliminary relative permeability estimates of methanehydrate-bearing sand

    SciTech Connect

    Seol, Yongkoo; Kneafsey, Timothy J.; Tomutsa, Liviu; Moridis,George J.

    2006-05-08

    The relative permeability to fluids in hydrate-bearing sediments is an important parameter for predicting natural gas production from gas hydrate reservoirs. We estimated the relative permeability parameters (van Genuchten alpha and m) in a hydrate-bearing sand by means of inverse modeling, which involved matching water saturation predictions with observations from a controlled waterflood experiment. We used x-ray computed tomography (CT) scanning to determine both the porosity and the hydrate and aqueous phase saturation distributions in the samples. X-ray CT images showed that hydrate and aqueous phase saturations are non-uniform, and that water flow focuses in regions of lower hydrate saturation. The relative permeability parameters were estimated at two locations in each sample. Differences between the estimated parameter sets at the two locations were attributed to heterogeneity in the hydrate saturation. Better estimates of the relative permeability parameters require further refinement of the experimental design, and better description of heterogeneity in the numerical inversions.

  19. Preliminary Findings on Searcher Performance and Perceptions of Performance in a Hypertext Bibliographic Retrieval System.

    ERIC Educational Resources Information Center

    Wolfram, Dietmar; Dimitroff, Alexandra

    1997-01-01

    Although hypertext system usage has been studied, little research has examined the relationship of searcher performance and perception of performance, particularly for hypertext-based information retrieval systems for bibliographic data. This article reports preliminary findings of a study at the University of Wisconsin-Milwaukee in which 83…

  20. Preliminary Findings on Searcher Performance and Perceptions of Performance in a Hypertext Bibliographic Retrieval System.

    ERIC Educational Resources Information Center

    Wolfram, Dietmar; Dimitroff, Alexandra

    1997-01-01

    Although hypertext system usage has been studied, little research has examined the relationship of searcher performance and perception of performance, particularly for hypertext-based information retrieval systems for bibliographic data. This article reports preliminary findings of a study at the University of Wisconsin-Milwaukee in which 83…

  1. Preliminary results on estimating permeability characteristics of carbonate rocks using pore microstructures

    NASA Astrophysics Data System (ADS)

    Lee, M.; Keehm, Y.

    2013-12-01

    Direct numerical simulation on pore microstructures from X-ray microtomography is regarded as a good tool to determine and characterize the physical properties of rocks, especially for sandstone. When the same approach is considered for carbonate rocks, we face many difficulties mostly from the heterogeneous nature of carbonates. In this study, we report preliminary results on permeability estimation of carbonate rocks from X-ray tomographic pore microstructures. Since carbonate rocks have quite different types of pore geometry depending on depositional and diagenetic environments, we choose three rock samples with different porosity types: interparticle; vuggy/moldic; and fracture, and obtain high-resolution 3D pore microstructures using X-ray microtomography technique. From the original 3D pore geometry (typically 2,000^3 voxels), we choose various digital sub-blocks to determine local variation and length dependency, and calculate permeability using the Lattice-Boltzmann method. For the interparticle case, the calculated permeability values show very similar trends to clastic sediments, and we can determine a porosity-permeability relation for a given formation as we do with the Koneny-Carman relation. On the other hand, for vuggy or fracture cases, we cannot observe any significant dependence of permeability on porosity. Thus we focus more on the local variation and scale variation of permeability. We perform analyses on percolation probability; local porosity distribution; and direction/length/width of fractures. And we present preliminary conceptual models to determine permeability characteristics. Although the results are from a few limited samples and more detailed researches will be required, our approach will be helpful to estimate and characterize permeability of carbonate rocks, and to investigate scaling and representativeness issues. Acknowledgements: This research was supported by the Basic Research Project of the Korea Institute of Geoscience and

  2. Preliminary supersonic flight test evaluation of performance seeking control

    NASA Technical Reports Server (NTRS)

    Orme, John S.; Gilyard, Glenn B.

    1993-01-01

    Digital flight and engine control, powerful onboard computers, and sophisticated controls techniques may improve aircraft performance by maximizing fuel efficiency, maximizing thrust, and extending engine life. An adaptive performance seeking control system for optimizing the quasi-steady state performance of an F-15 aircraft was developed and flight tested. This system has three optimization modes: minimum fuel, maximum thrust, and minimum fan turbine inlet temperature. Tests of the minimum fuel and fan turbine inlet temperature modes were performed at a constant thrust. Supersonic single-engine flight tests of the three modes were conducted using varied after burning power settings. At supersonic conditions, the performance seeking control law optimizes the integrated airframe, inlet, and engine. At subsonic conditions, only the engine is optimized. Supersonic flight tests showed improvements in thrust of 9 percent, increases in fuel savings of 8 percent, and reductions of up to 85 deg R in turbine temperatures for all three modes. The supersonic performance seeking control structure is described and preliminary results of supersonic performance seeking control tests are given. These findings have implications for improving performance of civilian and military aircraft.

  3. Charts for graphical estimation of airplane performance

    NASA Technical Reports Server (NTRS)

    Diehl, Walter S

    1925-01-01

    This report contains a series of charts which were developed in order to simplify the estimation of airplane performance. Charts are given for estimating propeller diameter and efficiency, maximum speed, initial rate of climb, absolute ceiling, service ceiling, climb in 10 minutes, time to climb to any altitude, maximum speed at any altitude, and endurance. A majority of these charts are based on the equations given in NACA Technical Report no. 173. Plots of pressure and density against altitude in standard air are also given for convenience. It must be understood that the charts giving propeller diameter, maximum speed, initial rate of climb, absolute ceiling, and speeds at altitudes are approximations subject to considerable error under certain conditions. These particular charts should not be used as a substitute for detailed calculations when accuracy is required, as, for example, in military proposals. (author)

  4. Preliminary investigations of HE performance characterization using SWIFT

    NASA Astrophysics Data System (ADS)

    Murphy, M. J.; Johnson, C. E.

    2014-05-01

    Preliminary experiments are performed to assess the utility of using the shock wave image framing technique (SWIFT) to characterize high explosive (HE) performance on detonator length and time scales. Columns of XTX 8004, an extrudable RDX-based high explosive, are cured directly within polymethylmethacrylate (PMMA) dynamic witness plates, and SWIFT is employed to directly visualize shock waves driven into PMMA through detonation interaction. Current experiments investigate two-dimensional, axisymmetric test geometries that resemble historic aquarium tests, but on millimeter length scales, and the SWIFT system records 16-frame, time-resolved image sequences at 190 ns inter-framing. Detonation wave velocities are accurately calculated from the time-resolved images, and standard aquarium-test analysis is evaluated to investigate calculated shock pressures at the HE/PMMA interface. Experimental SWIFT results are discussed where the charge diameter of XTX 8004 is varied from 2.0 mm to 6.5 mm.

  5. The Use of Artificial Neural Networks to Estimate Speech Intelligibility from Acoustic Variables: A Preliminary Analysis.

    ERIC Educational Resources Information Center

    Metz, Dale Evan; And Others

    1992-01-01

    A preliminary scheme for estimating the speech intelligibility of hearing-impaired speakers from acoustic parameters, using a computerized artificial neural network to process mathematically the acoustic input variables, is outlined. Tests with 60 hearing-impaired speakers found the scheme to be highly accurate in identifying speakers separated by…

  6. 43 CFR 11.38 - Assessment Plan-preliminary estimate of damages.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... restoration, rehabilitation, replacement, and/or acquisition of equivalent resources for the injured natural resources; and the compensable value, as defined in § 11.83(c) of this part, of the injured natural... natural resources. (i) The preliminary estimate of costs should take into account the effects,...

  7. Preliminary crown weight estimates for tanoak, black oak, and Pacific madrone.

    Treesearch

    J.A. Kendall. Snell

    1979-01-01

    Preliminary tables for estimating dry weights of whole trees and of crown components are presented for California blackuoak and tanoak; total tree weight only for Pacific madrone. Crown component weights were generated from data of two earlier studies, one from the Appalachians and one from the Pacific Northwest.

  8. The Use of Artificial Neural Networks to Estimate Speech Intelligibility from Acoustic Variables: A Preliminary Analysis.

    ERIC Educational Resources Information Center

    Metz, Dale Evan; And Others

    1992-01-01

    A preliminary scheme for estimating the speech intelligibility of hearing-impaired speakers from acoustic parameters, using a computerized artificial neural network to process mathematically the acoustic input variables, is outlined. Tests with 60 hearing-impaired speakers found the scheme to be highly accurate in identifying speakers separated by…

  9. Preliminary weight and cost estimates for transport aircraft composite structural design concepts

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Preliminary weight and cost estimates have been prepared for design concepts utilized for a transonic long range transport airframe with extensive applications of advanced composite materials. The design concepts, manufacturing approach, and anticipated details of manufacturing cost reflected in the composite airframe are substantially different from those found in conventional metal structure and offer further evidence of the advantages of advanced composite materials.

  10. 43 CFR 11.38 - Assessment Plan-preliminary estimate of damages.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... restoration, rehabilitation, replacement, and/or acquisition of equivalent resources for the injured natural resources; and the compensable value, as defined in § 11.83(c) of this part, of the injured natural... natural resources. (i) The preliminary estimate of costs should take into account the effects,...

  11. Preliminary Analysis of IGS Reprocessed Orbit and Polar Motion Estimates

    NASA Astrophysics Data System (ADS)

    Ray, J. R.; Griffiths, J.

    2009-04-01

    The Analysis Centers (ACs) of the International GNSS Service (IGS) are reanalyzing the history of global network GPS data collected since 1994 in a consistent way using the latest models and methodology. This is the first reprocessing by the IGS, but it is expected to be repeated in the future as further analysis and reference frame changes occur. All eight final-product ACs are participating, together with three other related groups. First partial results consisting of IGS combined weekly SINEX TRF and EOP combinations have been submitted to the IERS for ITRF2008. A snapshot of the available AC weekly SINEX files was used covering the reprocessed years 2000 through 2007 plus the IGS regular operational solutions for 2008 (from week 1460 onward). Meanwhile, the full reprocessing campaign will continue to completion by about the end of 2009 and will cover the period 1994 to present with long-term consistent, combined SINEX, orbit, and clock products. We have examined the reprocessed AC orbit and polar motion (PM) estimates from the 1024 days (or 1025 for differences) of results till the end of 2007. These parameters are linked since PM is sensed in the GPS modeling as a global diurnal sinusoidal motion of the terrestrial frame relative to the satellite frame. Any similar type errors in the orbital frame can bias the PM and PM rate estimates. For the orbits, each daily AC satellite ephemeris for each pair of consecutive days has been fit to the extended CODE orbit model, extrapolated to the mid-point epoch between the days, and the geocentric satellite position differences computed to give time series of orbit repeatabilities. Occasional data gaps have been filled by linear interpolation, FFT power spectra computed, and the spectra stacked over the full GPS constellation and lightly smoothed. Our analysis reveals considerable diversity among AC orbits. Several show broad semi-annual (probably related mostly to eclipsing) and fortnightly spectral peaks, as well as

  12. Sexual functioning in military personnel: preliminary estimates and predictors.

    PubMed

    Wilcox, Sherrie L; Redmond, Sarah; Hassan, Anthony M

    2014-10-01

    Although the military is a young and vigorous force, service members and veterans may experience sexual functioning problems (SFPs) as a result of military service. Sexual functioning can be impaired by physical, psychological, and social factors and can impact quality of life (QOL) and happiness. This study aims to estimate rates and correlates of SFPs in male military personnel across demographic and psychosocial characteristics, to examine the QOL concomitants, and to evaluate barriers for treatment seeking. This exploratory cross-sectional study was conducted using data from a larger nationwide study conducted between October 2013 and November 2013. This sample consists of 367 male active duty service members and recent veterans (military personnel) age 40 or younger. Erectile dysfunction (ED) was determined using the five-item International Index of Erectile Function, sexual dysfunction (SD) was determined using the Arizona Sexual Experiences Scale, Male, and QOL was determined using the World Health Organization Quality of Life, Brief. SFPs were associated with various demographic, physical, and psychosocial risk factors. The rates of SD and ED were 8.45% and 33.24%, respectively, for male military personnel aged 21-40. Those who were 36-40, nonmarried, nonwhite, and of lower educational attainment reported the highest rates of SFPs. Male military personnel with poor physical and psychosocial health presented the greatest risk for ED and SD. SFPs were associated with reduced QOL and lower happiness, and barriers for treatment were generally related to social barriers. SFPs in young male military personnel are an important public health concern that can severely impact QOL and happiness. © 2014 International Society for Sexual Medicine.

  13. The Gemini Planet Imager Coronagraph Testbed Preliminary Performance Results

    NASA Astrophysics Data System (ADS)

    Roberts, Robin

    2010-01-01

    The Gemini Planet Imager (GPI) is a new science instrument being developed and slated for first light early 2011 on the twin 8m Gemini telescopes. Operating in the near infrared, this ground-based, extreme Adaptive Optics (ExAO) coronographic instrument will provide the ability to detect, characterize and analyze young (< 2GYr), self-luminous, extrasolar planets with brightness contrast ratios ≤ 10-7 when compared to their parent star. The coronagraph subsystem includes a pupil apodization, a hard-edged focal plane mask as well as a Lyot stop. Preliminary results indicate that the testbed is performing at very high contrast, having achieved broadband contrasts (H-band) below 10-6 at separations > 5λ/D. Fraunhoffer and Fresnel propagation modeling were used to analyze the testbed results.

  14. 4MOST fiber feed preliminary design: prototype testing and performance

    NASA Astrophysics Data System (ADS)

    Haynes, Dionne M.; Kelz, Andreas; Barden, Samuel C.; Bauer, Svend-Marian; Ehrlich, Katjana; Haynes, Roger; Jahn, Thomas; Saviauk, Allar; de Jong, Roelof S.

    2016-08-01

    The 4MOST instrument is a multi-object-spectrograph for the ESO-VISTA telescope. The 4MOST fiber feed subsystem is composed of a fiber positioner (AESOP) holding 2436 science fibers based on the Echidna tilting spine concept, and the fiber cable, which feeds two low-resolution spectrographs (1624 fibers) and one high-resolution spectrograph (812 fibers). In order to optimize the fiber feed subsystem design and provide essential information required for the spectrograph design, prototyping and testing has been undertaken. In this paper we give an overview of the current fiber feed subsystem design and present the preliminary FRD, scrambling, throughput and system performance impact results for: maximum and minimum spine tilt, fiber connectors, cable de-rotator simulator for fiber cable lifetime tests.

  15. Advanced stellar compass onboard autonomous orbit determination, preliminary performance.

    PubMed

    Betto, Maurizio; Jørgensen, John L; Jørgensen, Peter S; Denver, Troelz

    2004-05-01

    Deep space exploration is in the agenda of the major space agencies worldwide; certainly the European Space Agency (SMART Program) and the American NASA (New Millennium Program) have set up programs to allow the development and the demonstration of technologies that can reduce the risks and the cost of deep space missions. From past experience, it appears that navigation is the Achilles heel of deep space missions. Performed on ground, this imposes considerable constraints on the entire system and limits operations. This makes it is very expensive to execute, especially when the mission lasts several years and, furthermore, it is not failure tolerant. Nevertheless, to date, ground navigation has been the only viable solution. The technology breakthrough of advanced star trackers, like the advanced stellar compass (ASC), might change this situation. Indeed, exploiting the capabilities of this instrument, the authors have devised a method to determine the orbit of a spacecraft autonomously, onboard, and without a priori knowledge of any kind. The solution is robust and fast. This paper presents the preliminary performance obtained during the ground testing in August 2002 at the Mauna Kea Observatories. The main goals were: (1) to assess the robustness of the method in solving autonomously, onboard, the position lost-in-space problem; (2) to assess the preliminary accuracy achievable with a single planet and a single observation; (3) to verify the autonomous navigation (AutoNav) module could be implemented into an ASC without degrading the attitude measurements; and (4) to identify the areas of development and consolidation. The results obtained are very encouraging.

  16. Preliminary Scaling Estimate for Select Small Scale Mixing Demonstration Tests

    SciTech Connect

    Wells, Beric E.; Fort, James A.; Gauglitz, Phillip A.; Rector, David R.; Schonewill, Philip P.

    2013-09-12

    The Hanford Site double-shell tank (DST) system provides the staging location for waste that will be transferred to the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Specific WTP acceptance criteria for waste feed delivery describe the physical and chemical characteristics of the waste that must be met before the waste is transferred from the DSTs to the WTP. One of the more challenging requirements relates to the sampling and characterization of the undissolved solids (UDS) in a waste feed DST because the waste contains solid particles that settle and their concentration and relative proportion can change during the transfer of the waste in individual batches. A key uncertainty in the waste feed delivery system is the potential variation in UDS transferred in individual batches in comparison to an initial sample used for evaluating the acceptance criteria. To address this uncertainty, a number of small-scale mixing tests have been conducted as part of Washington River Protection Solutions’ Small Scale Mixing Demonstration (SSMD) project to determine the performance of the DST mixing and sampling systems.

  17. Novel Estimation of Pilot Performance Characteristics

    NASA Technical Reports Server (NTRS)

    Bachelder, Edward N.; Aponso, Bimal

    2017-01-01

    Two mechanisms internal to the pilot that affect performance during a tracking task are: 1) Pilot equalization (i.e. lead/lag); and 2) Pilot gain (i.e. sensitivity to the error signal). For some applications McRuer's Crossover Model can be used to anticipate what equalization will be employed to control a vehicle's dynamics. McRuer also established approximate time delays associated with different types of equalization - the more cognitive processing that is required due to equalization difficulty, the larger the time delay. However, the Crossover Model does not predict what the pilot gain will be. A nonlinear pilot control technique, observed and coined by the authors as 'amplitude clipping', is shown to improve stability, performance, and reduce workload when employed with vehicle dynamics that require high lead compensation by the pilot. Combining linear and nonlinear methods a novel approach is used to measure the pilot control parameters when amplitude clipping is present, allowing precise measurement in real time of key pilot control parameters. Based on the results of an experiment which was designed to probe workload primary drivers, a method is developed that estimates pilot spare capacity from readily observable measures and is tested for generality using multi-axis flight data. This paper documents the initial steps to developing a novel, simple objective metric for assessing pilot workload and its variation over time across a wide variety of tasks. Additionally, it offers a tangible, easily implementable methodology for anticipating a pilot's operating parameters and workload, and an effective design tool. The model shows promise in being able to precisely predict the actual pilot settings and workload, and observed tolerance of pilot parameter variation over the course of operation. Finally, an approach is proposed for generating Cooper-Harper ratings based on the workload and parameter estimation methodology.

  18. Performance benchmarking of liver CT image segmentation and volume estimation

    NASA Astrophysics Data System (ADS)

    Xiong, Wei; Zhou, Jiayin; Tian, Qi; Liu, Jimmy J.; Qi, Yingyi; Leow, Wee Kheng; Han, Thazin; Wang, Shih-chang

    2008-03-01

    In recent years more and more computer aided diagnosis (CAD) systems are being used routinely in hospitals. Image-based knowledge discovery plays important roles in many CAD applications, which have great potential to be integrated into the next-generation picture archiving and communication systems (PACS). Robust medical image segmentation tools are essentials for such discovery in many CAD applications. In this paper we present a platform with necessary tools for performance benchmarking for algorithms of liver segmentation and volume estimation used for liver transplantation planning. It includes an abdominal computer tomography (CT) image database (DB), annotation tools, a ground truth DB, and performance measure protocols. The proposed architecture is generic and can be used for other organs and imaging modalities. In the current study, approximately 70 sets of abdominal CT images with normal livers have been collected and a user-friendly annotation tool is developed to generate ground truth data for a variety of organs, including 2D contours of liver, two kidneys, spleen, aorta and spinal canal. Abdominal organ segmentation algorithms using 2D atlases and 3D probabilistic atlases can be evaluated on the platform. Preliminary benchmark results from the liver segmentation algorithms which make use of statistical knowledge extracted from the abdominal CT image DB are also reported. We target to increase the CT scans to about 300 sets in the near future and plan to make the DBs built available to medical imaging research community for performance benchmarking of liver segmentation algorithms.

  19. Preliminary Analysis of Remote Monitoring & Robotic Concepts for Performance Confirmation

    SciTech Connect

    D.A. McAffee

    1997-02-18

    main Performance Confirmation monitoring needs and requirements during the post-emplacement preclosure period. This includes radiological, non-radiological, host rock, and infrastructure performance monitoring needs. It also includes monitoring for possible off-normal events. (Presented in Section 7.3). (3) Identify general approaches and methods for obtaining performance information from within the emplacement drifts for Performance Confirmation. (Presented in Section 7.4) (4)Review and discuss available technologies and design strategies that may permit the use of remotely operated systems within the hostile thermal and radiation environment expected within the emplacement drifts. (Presented in Section 7.5). (5) Based on Performance Confirmation monitoring needs and available technologies, identify potential application areas for remote systems and robotics for post-emplacement preclosure Performance Confirmation activities (Presented in Section 7.6). (6) Develop preliminary remote monitoring and robotic concepts for post-emplacement, preclosure Performance Confirmation activities. (Presented in Section 7.7) This analysis is being performed very early in the systems engineering cycle, even as issues related to the Performance Confirmation program planning phase are being formulated and while the associated needs, constraints and objectives are yet to be fully determined and defined. This analysis is part of an issue formulation effort and is primarily concerned with identification and description of key issues related to remotely monitoring repository performance for Performance Confirmation. One of the purposes of this analysis is to provide an early investigation of potential design challenges that may have a high impact on future design concepts. This analysis can be used to guide future concept development and help access what is feasible and achievable by application of remote systems technology. Future design and systems engineering analysis with applicable

  20. A Nonlinear Dynamics-Based Estimator for Functional Electrical Stimulation: Preliminary Results from Lower-Leg Extension Experiments.

    PubMed

    Allen, Marcus; Zhong, Qiang; Kirsch, Nicholas; Dani, Ashwin; Clark, William W; Sharma, Nitin

    2017-09-07

    Miniature inertial measurement units (IMUs) are wearable sensors that measure limb segment or joint angles during dynamic movements. However, IMUs are generally prone to drift, external magnetic interference, and measurement noise. This paper presents a new class of nonlinear state estimation technique called state-dependent coefficient (SDC) estimation to accurately predict joint angles from IMU measurements. The SDC estimation method uses limb dynamics, instead of limb kinematics, to estimate the limb state. Importantly, the nonlinear limb dynamic model is formulated into state dependent matrices that facilitate the estimator design without performing a Jacobian linearization. The estimation method is experimentally demonstrated to predict knee joint angle measurements during functional electrical stimulation of the quadriceps muscle. The nonlinear knee musculoskeletal model was identified through a series of experiments. The SDC estimator was then compared to an Extended Kalman filter (EKF), which uses a Jacobian linearization and a rotation matrix method, which uses a kinematic model instead of the dynamic model. Each estimator's performance was evaluated against the true value of the joint angle, which was measured through a rotary encoder. The experimental results showed that the SDC estimator, the rotation matrix method, and EKF had root mean square errors of 2.70°, 2.86°, and 4.42°, respectively. Our preliminary experimental results show the new estimator's advantage over the EKF method but a slight advantage over the rotation matrix method. However, the information from the dynamic model allows the SDC method to use only one IMU to measure the knee angle compared to the rotation matrix method that uses 2 IMUs to estimate the angle.

  1. Preliminary investigation of an ultrasound method for estimating pressure changes in deep-positioned vessels

    NASA Astrophysics Data System (ADS)

    Olesen, Jacob Bjerring; Villagomez-Hoyos, Carlos Armando; Traberg, Marie Sand; Chee, Adrian J. Y.; Yiu, Billy Y. S.; Ho, Chung Kit; Yu, Alfred C. H.; Jensen, Jørgen Arendt

    2016-04-01

    This paper presents a method for measuring pressure changes in deep-tissue vessels using vector velocity ultrasound data. The large penetration depth is ensured by acquiring data using a low frequency phased array transducer. Vascular pressure changes are then calculated from 2-D angle-independent vector velocity fields using a model based on the Navier-Stokes equations. Experimental scans are performed on a fabricated flow phantom having a constriction of 36% at a depth of 100 mm. Scans are carried out using a phased array transducer connected to the experimental scanner, SARUS. 2-D fields of angle-independent vector velocities are acquired using directional synthetic aperture vector flow imaging. The obtained results are evaluated by comparison to a 3-D numerical simulation model with equivalent geometry as the designed phantom. The study showed pressure drops across the constricted phantom varying from -40 Pa to 15 Pa with a standard deviation of 32%, and a bias of 25% found relative to the peak simulated pressure drop. This preliminary study shows that pressure can be estimated non-invasively to a depth that enables cardiac scans, and thereby, the possibility of detecting the pressure drops across the mitral valve.

  2. Enhancement of perfluoropolyether boundary lubrication performance: I. Preliminary results

    NASA Technical Reports Server (NTRS)

    Jones, W. R., Jr.; Ajayi, O. O.; Goodell, A. J.; Wedeven, L. D.; Devine, E.; Premore, R. E.

    1995-01-01

    A ball bearing simulator operating under starved conditions was used to evaluate the boundary lubrication performance of a perfluoropolyether (PFPE) Krytox 143 AB. Several approaches to enhance boundary lubrication were studied. These included: (1) soluble boundary additives, (2) bearing surface modifications, (3) 'run-in' surface films, and (4) ceramic bearing components. In addition, results were compared with two non-perfluorinated liquid lubricant formulations. Based on these preliminary tests, the following tentative conclusions can be made: (1) substantial improvements in boundary lubrication performance were observed with a beta-diketone boundary additive and a tricresyl phosphate (TCP) liquid surface pretreatment; (2) the use of rough Si3N4 balls (Ra = 40 micro-in) also provided substantial improvement but with concomitant abrasive wear; (3) marginal improvements were seen with two boundary additives (a phosphine and a phosphatriazine) and a neat (100%) fluid (a carboxylic acid terminated PFPE); and surface pretreatments with a synthetic hydrocarbon, a PTFE coating, and TiC coated 440C and smooth Si3N4 balls (R(sub a) less than 1 micro-in); and (4) two non-PFPE lubricant formulations (a PAO and a synthetic hydrocarbon) yielded substantial improvements.

  3. EGADS: A microcomputer program for estimating the aerodynamic performance of general aviation aircraft

    NASA Technical Reports Server (NTRS)

    Melton, John E.

    1994-01-01

    EGADS is a comprehensive preliminary design tool for estimating the performance of light, single-engine general aviation aircraft. The software runs on the Apple Macintosh series of personal computers and assists amateur designers and aeronautical engineering students in performing the many repetitive calculations required in the aircraft design process. The program makes full use of the mouse and standard Macintosh interface techniques to simplify the input of various design parameters. Extensive graphics, plotting, and text output capabilities are also included.

  4. Development of the wireless ultra-miniaturized inertial measurement unit WB-4: preliminary performance evaluation.

    PubMed

    Lin, Zhuohua; Zecca, Massimiliano; Sessa, Salvatore; Bartolomeo, Luca; Ishii, Hiroyuki; Takanishi, Atsuo

    2011-01-01

    This paper presents the preliminary performance evaluation of our new wireless ultra-miniaturized inertial measurement unit (IMU) WB-4 by compared with the Vicon motion capture system. The WB-4 IMU primarily contains a mother board for motion sensing, a Bluetooth module for wireless data transmission with PC, and a Li-Polymer battery for power supply. The mother board is provided with a microcontroller and 9-axis inertial sensors (miniaturized MEMS accelerometer, gyroscope and magnetometer) to measure orientation. A quaternion-based extended Kalman filter (EKF) integrated with an R-Adaptive algorithm for automatic estimation of the measurement covariance matrix is implemented for the sensor fusion to retrieve the attitude. The experimental results showed that the wireless ultra-miniaturized WB-4 IMU could provide high accuracy performance at the angles of roll and pitch. The yaw angle which has reasonable performance needs to be further evaluated.

  5. APPENDIX C. PRELIMINARY ESTIMATES OF COSTS OF MERCURY EMISSION CONTROL TECHNOLOGIES FOR ELECTRIC UTILITY BOILERS

    EPA Science Inventory

    This appendix describes the development of a preliminary assessment of the performance and cost of mercury emission control technologies for utility boilers. It is to supplement an EPA examination of the co-benefits of potential pollution control options for the electric power in...

  6. APPENDIX C. PRELIMINARY ESTIMATES OF COSTS OF MERCURY EMISSION CONTROL TECHNOLOGIES FOR ELECTRIC UTILITY BOILERS

    EPA Science Inventory

    This appendix describes the development of a preliminary assessment of the performance and cost of mercury emission control technologies for utility boilers. It is to supplement an EPA examination of the co-benefits of potential pollution control options for the electric power in...

  7. Accuracy of jitter estimates using different filter settings on Visi-Pitch: a preliminary report.

    PubMed

    Perry, C K; Ingrisano, D R; Scott, S R

    1996-12-01

    Preliminary findings are presented regarding Visi-Pitch settings in relation to automatically derived perturbation values (jitter). Jitter values were estimated from sustained phonation of /a/ at each of four filter settings for three subjects using Visi-Pitch. Data were compared to values obtained by hand measuring the same signals and employing Koike's formula. Results indicated that the magnitude of difference between jitter estimated by Visi-Pitch and hand measurement was small. Findings support the use of the manufacturer's recommended filter settings as opposed to alternative settings suggested by Karnell.

  8. Design and Preliminary Performance Testing of Electronegative Gas Plasma Thruster

    NASA Technical Reports Server (NTRS)

    Liu, Thomas M.; Schloeder, Natalie R.; Walker, Mitchell L. R.; Polzin, Kurt A.; Dankanich, John W.; Aanesland, Ane

    2014-01-01

    In classical gridded electrostatic ion thrusters, positively charged ions are generated from a plasma discharge of noble gas propellant and accelerated to provide thrust. To maintain overall charge balance on the propulsion system, a separate electron source is required to neutralize the ion beam as it exits the thruster. However, if high-electronegativity propellant gases (e.g., sulfur hexafluoride) are instead used, a plasma discharge can result consisting of both positively and negatively charged ions. Extracting such electronegative plasma species for thrust generation (e.g., with time-varying, bipolar ion optics) would eliminate the need for a separate neutralizer cathode subsystem. In addition for thrusters utilizing a RF plasma discharge, further simplification of the ion thruster power system may be possible by also using the RF power supply to bias the ion optics. Recently, the PEGASES (Plasma propulsion with Electronegative gases) thruster prototype successfully demonstrated proof-of-concept operations in alternatively accelerating positively and negatively charged ions from a RF discharge of a mixture of argon and sulfur hexafluoride.i In collaboration with NASA Marshall Space Flight Center (MSFC), the Georgia Institute of Technology High-Power Electric Propulsion Laboratory (HPEPL) is applying the lessons learned from PEGASES design and testing to develop a new thruster prototype. This prototype will incorporate design improvements and undergo gridless operational testing and diagnostics checkout at HPEPL in April 2014. Performance mapping with ion optics will be conducted at NASA MSFC starting in May 2014. The proposed paper discusses the design and preliminary performance testing of this electronegative gas plasma thruster prototype.

  9. Preliminary Performance of CdZnTe Imaging Detector Prototypes

    NASA Technical Reports Server (NTRS)

    Ramsey, B.; Sharma, D. P.; Meisner, J.; Gostilo, V.; Ivanov, V.; Loupilov, A.; Sokolov, A.; Sipila, H.

    1999-01-01

    The promise of good energy and spatial resolution coupled with high efficiency and near-room-temperature operation has fuelled a large International effort to develop Cadmium-Zinc-Telluride (CdZnTe) for the hard-x-ray region. We present here preliminary results from our development of small-pixel imaging arrays fabricated on 5x5x1-mm and 5x5x2-mm spectroscopy and discriminator-grade material. Each array has 16 (4x4) 0.65-mm gold readout pads on a 0.75-mm pitch, with each pad connected to a discrete preamplifier via a pulse-welded gold wire. Each array is mounted on a 3-stage Peltier cooler and housed in an ion-pump-evacuated housing which also contains a hybrid micro-assembly for the 16 channels of electronics. We have investigated the energy resolution and approximate photopeak efficiency for each pixel at several energies and have used an ultra-fine beam x-ray generator to probe the performance at the pixel boundaries. Both arrays gave similar results, and at an optimum temperature of -20 C we achieved between 2 and 3% FWHM energy resolution at 60 keV and around 15% at 5.9 keV. We found that all the charge was contained within 1 pixel until very close to the pixels edge, where it would start to be shared with its neighbor. Even between pixels, all the charge would be appropriately shared with no apparently loss of efficiency or resolution. Full details of these measurements will be presented, together with their implications for future imaging-spectroscopy applications.

  10. Preliminary Performance of CdZnTe Imaging Detector Prototypes

    NASA Technical Reports Server (NTRS)

    Ramsey, B.; Sharma, D. P.; Meisner, J.; Gostilo, V.; Ivanov, V.; Loupilov, A.; Sokolov, A.; Sipila, H.

    1999-01-01

    The promise of good energy and spatial resolution coupled with high efficiency and near-room-temperature operation has fuelled a large International effort to develop Cadmium-Zinc-Telluride (CdZnTe) for the hard-x-ray region. We present here preliminary results from our development of small-pixel imaging arrays fabricated on 5x5x1-mm and 5x5x2-mm spectroscopy and discriminator-grade material. Each array has 16 (4x4) 0.65-mm gold readout pads on a 0.75-mm pitch, with each pad connected to a discrete preamplifier via a pulse-welded gold wire. Each array is mounted on a 3-stage Peltier cooler and housed in an ion-pump-evacuated housing which also contains a hybrid micro-assembly for the 16 channels of electronics. We have investigated the energy resolution and approximate photopeak efficiency for each pixel at several energies and have used an ultra-fine beam x-ray generator to probe the performance at the pixel boundaries. Both arrays gave similar results, and at an optimum temperature of -20 C we achieved between 2 and 3% FWHM energy resolution at 60 keV and around 15% at 5.9 keV. We found that all the charge was contained within 1 pixel until very close to the pixels edge, where it would start to be shared with its neighbor. Even between pixels, all the charge would be appropriately shared with no apparently loss of efficiency or resolution. Full details of these measurements will be presented, together with their implications for future imaging-spectroscopy applications.

  11. Notification: Preliminary Research: Review of Independent Government Cost Estimates and Indirect Costs for EPA’s Interagency Agreements

    EPA Pesticide Factsheets

    Project #OA-FY14-0130, February 11, 2014. The EPA OIG plans to begin preliminary research of the independent government cost estimates and indirect costs for the EPA's funds-in interagency agreements.

  12. Preliminary age, growth and maturity estimates of spotted ratfish (Hydrolagus colliei) in British Columbia

    NASA Astrophysics Data System (ADS)

    King, J. R.; McPhie, R. P.

    2015-05-01

    The spotted ratfish (Hydrolagus colliei) is a chimaeroid ranging from southeast Alaska to Baja California and found at depths of up to 1029 m. Despite being widespread and ubiquitous, few biological parameter estimates exist for spotted ratfish due to a lack of suitable ageing structures to estimate age and growth. We present preliminary results of age, growth and maturity estimates based on a new method in which tritor ridges are counted on the vomerine tooth plate. We also provide a method for estimating the number of worn tritor ridges based on tooth plate diameter measurements for the spotted ratfish. The tritor ridges are distinct bumps that are easy to identify and precision estimates between readers suggests that this method is transferable. Tritor ridges are a potential structure for estimating age in H. colliei and we provide recommendations for future research to improve the method. We sampled 269 spotted ratfish captured in trawl surveys off the coast British Columbia ranging in size from 74 to 495 mm in precaudal length (PCL). The estimated ages ranged from 2 to 16 years for males and from 2 to 21 years for females. The von Bertalanffy, von Bertalanffy with known size at birth, Gompertz and logistic growth models were fitted to the data. Based on Akaike information criterion corrected for sample size and number of parameters estimated, the logistic growth curve was selected as most suitable. The logistic growth model yielded the following parameter estimates: Linf=407.22 mm (PCL), k=0.23 year-1, t0=-7.06 years for males; L∞=494.52 mm (PCL), k=0.26 year-1, t0=-8.35 years for females. Estimated ages at 50% maturity were 12 and 14 years for males and females, respectively. Correspondingly, the size at 50% maturity estimates was smaller for males (302 mm, PCL) than females (393 mm, PCL). Both estimates are larger than those made for spotted ratfish off of California indicating regional differences in life history traits for this species. Our preliminary

  13. Preliminary performance assessment for the Waste Isolation Pilot Plant, December 1992. Volume 2, Technical basis

    SciTech Connect

    Not Available

    1992-12-01

    Before disposing of transuranic radioactive waste in the Waste Isolation Pilot Plant (WIPP), the United States Department of Energy (DOE) must evaluate compliance with applicable long-term regulations of the United States Environmental Protection Agency (EPA). Sandia National Laboratories is conducting iterative performance assessments (PAs) of the WIPP for the DOE to provide interim guidance while preparing for a final compliance evaluation. This volume, Volume 2, contains the technical basis for the 1992 PA. Specifically, it describes the conceptual basis for consequence modeling and the PA methodology, including the selection of scenarios for analysis, the determination of scenario probabilities, and the estimation of scenario consequences using a Monte Carlo technique and a linked system of computational models. Additional information about the 1992 PA is provided in other volumes. Volume I contains an overview of WIPP PA and results of a preliminary comparison with the long-term requirements of the EPA`s Environmental Protection Standards for Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Radioactive Wastes (40 CFR 191, Subpart B). Volume 3 contains the reference data base and values for input parameters used in consequence and probability modeling. Volume 4 contains uncertainty and sensitivity analyses related to the preliminary comparison with 40 CFR 191B. Volume 5 contains uncertainty and sensitivity analyses of gas and brine migration for undisturbed performance. Finally, guidance derived from the entire 1992 PA is presented in Volume 6.

  14. MEASUREMENT: ACCOUNTING FOR RELIABILITY IN PERFORMANCE ESTIMATES.

    PubMed

    Waterman, Brian; Sutter, Robert; Burroughs, Thomas; Dunagan, W Claiborne

    2014-01-01

    When evaluating physician performance measures, physician leaders are faced with the quandary of determining whether departures from expected physician performance measurements represent a true signal or random error. This uncertainty impedes the physician leader's ability and confidence to take appropriate performance improvement actions based on physician performance measurements. Incorporating reliability adjustment into physician performance measurement is a valuable way of reducing the impact of random error in the measurements, such as those caused by small sample sizes. Consequently, the physician executive has more confidence that the results represent true performance and is positioned to make better physician performance improvement decisions. Applying reliability adjustment to physician-level performance data is relatively new. As others have noted previously, it's important to keep in mind that reliability adjustment adds significant complexity to the production, interpretation and utilization of results. Furthermore, the methods explored in this case study only scratch the surface of the range of available Bayesian methods that can be used for reliability adjustment; further study is needed to test and compare these methods in practice and to examine important extensions for handling specialty-specific concerns (e.g., average case volumes, which have been shown to be important in cardiac surgery outcomes). Moreover, it's important to note that the provider group average as a basis for shrinkage is one of several possible choices that could be employed in practice and deserves further exploration in future research. With these caveats, our results demonstrate that incorporating reliability adjustment into physician performance measurements is feasible and can notably reduce the incidence of "real" signals relative to what one would expect to see using more traditional approaches. A physician leader who is interested in catalyzing performance improvement

  15. Intellectual Competence and Academic Performance: Preliminary Validation of a Model

    ERIC Educational Resources Information Center

    Chamorro-Premuzic, Tomas; Arteche, Adriane

    2008-01-01

    The present study provides a preliminary empirical test of [Chamorro-Premuzic, T., & Furnham, A. (2004). A possible model to understand the personality-intelligence interface. "British Journal of Psychology," 95, 249-264], [Chamorro-Premuzic, T., & Furnham, A. (2006a). Intellectual competence and the intelligent personality: A…

  16. Intellectual Competence and Academic Performance: Preliminary Validation of a Model

    ERIC Educational Resources Information Center

    Chamorro-Premuzic, Tomas; Arteche, Adriane

    2008-01-01

    The present study provides a preliminary empirical test of [Chamorro-Premuzic, T., & Furnham, A. (2004). A possible model to understand the personality-intelligence interface. "British Journal of Psychology," 95, 249-264], [Chamorro-Premuzic, T., & Furnham, A. (2006a). Intellectual competence and the intelligent personality: A…

  17. Preliminary estimates of galactic cosmic ray exposures for manned interplanetary missions

    SciTech Connect

    Wilson, J.W.; Townsend, L.W.; Atwell, W.

    1987-10-01

    Preliminary estimates of radiation exposures resulting from galactic cosmic rays are presented for interplanetary missions. The calculations use the Naval Research Laboratory cosmic ray transport code. The heavy ion portion of the transport code can be used with any number of layers of target material, consisting of up to five different constituents per layer. The nucleonic portion of the transport code can be used with any number of layers of target material of arbitrary composition except hydrogen. Calculated galactic cosmic ray particle fluxes, doses, and dose equivalents behind various thicknesses of aluminum shielding are presented for solar maximum and solar minimum periods.

  18. Estimation of Croplands in West Africa using Global Land Cover and Land Use Datasets: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Adhikari, P.; de Beurs, K.

    2013-12-01

    Africa is vulnerable to the effects of global climate change resulting in reduced agricultural production and worsening food security. Studies show that Africa has the lowest cereal yield compared to other regions of the world. The situation is particularly dire in East, Central and West Africa. Despite their low cereal yield, the population of East, Central and West Africa has doubled between 1980 and 2007. Furthermore, West Africa has a history of severe and long droughts which have occasionally caused widespread famine. To understand how global climate change and land cover change have impacted crop production (yield) it is important to estimate croplands in the region. The objective of this study is to compare ten publicly available land cover and land use datasets, covering different time periods, to estimate croplands in West Africa. The land cover and land use data sets used cover the period from early 1990s to 2010. Preliminary results show a high variability in cropland estimates. For example, in Benin, the estimated cropland area varies from 2.5 to 21% of the total area, while it varies from 3 to 8% in Niger. Datasets with a finer resolution (≤ 1,000 m) have consistently estimated comparable cropland areas across all countries. Several categorical verification statistics such as probability of detection (POD), false alarm ratio (FAR) and critical success index are also used to analyze the correspondence between estimated and observed cropland pixels at the scales of 1 Km and 10 Km.

  19. Improving CAD performance in pulmonary embolism detection: preliminary investigation

    NASA Astrophysics Data System (ADS)

    Park, Sang Cheol; Chapman, Brian; Deible, Christopher; Lee, Sean; Zheng, Bin

    2010-03-01

    In this preliminary study, a new computer-aided detection (CAD) scheme for pulmonary embolism (PE) detection was developed and tested. The scheme applies multiple steps including lung segmentation, candidate extraction using intensity mask and tobogganing method, feature extraction, false positive reduction using a multifeature based artificial neural network (ANN) and a k-nearest neighbor (KNN) classifier to detect and classify suspicious PE lesions. In particular, a new method to define the surrounding background regions of interest (ROI) depicting PE candidates was proposed and tested in an attempt to reduce the detection of false positive regions. In this study, the authors also investigated following methods to improve CAD performance, which include a grouping and scoring method, feature selection using genetic algorithm, and limitation on allowed suspicious lesions to be cued in one examination. To test the scheme performance, a set of 20 chest CT examinations were selected. Among them, 18 are positive cases depicted 44 verified PE lesions and the remaining 2 were negative cases. The dataset was also divided into a training subset (9 examinations) and a testing subset (11 examinations), respectively. The experimental results showed when applying to the testing dataset CAD scheme using tobogganing method alone achieved 2D region-based sensitivity of 72.1% (220/305) and 3D lesion-based sensitivity of 83.3% (20/24) with total 19,653 2D false-positive (FP) PE regions (1,786.6 per case or approximately 6.3 per CT slice). Applying the proposed new method to improve lung region segmentation and better define the surrounding background ROI, the scheme reduced the region-based sensitivity by 6.5% to 65.6% or lesion-based sensitivity by 4.1% to 79.2% while reducing the FP rate by 65.6% to 6,752 regions (or 613.8 per case). After applying the methods of grouping, the maximum scoring, a genetic algorithm (GA) to delete "redundant" features, and limiting the maximum

  20. Preliminary estimates of the economic implications of addiction in the United Arab Emirates.

    PubMed

    Doran, C M

    2017-01-23

    This study aimed to provide preliminary estimates of the economic implications of addiction in the United Arab Emirates (UAE). Local and international data sources were used to derive estimates of substancerelated healthcare costs, lost productivity and criminal behaviour. From an estimated population of 8.26 million: ~1.47 million used tobacco (20.5% of adults); 380 085 used cannabis (> 5%); 14 077 used alcohol in a harmful manner (0.2%); and 1408 used opiates (0.02%). The cost of addiction was estimated at US$ 5.47 billion in 2012, equivalent to 1.4% of gross domestic product. Productivity costs were the largest contributor at US$ 4.79 billion (88%) followed by criminal behaviour at US$ 0.65 billion (12%). There were no data to estimate cost of: treating tobacco-related diseases, community education and prevention efforts, or social disharmony. Current data collection efforts are limited in their capacity to fully inform an appropriate response to addiction in the UAE. Resources are required to improve indicators of drug use, monitor harm and evaluate treatment.

  1. Estimating Inter-Deployment Training Cycle Performances

    DTIC Science & Technology

    2003-12-01

    DEPLOYMENT TRAINING CYCLE PERFORMANCES by Levent Eriskin December 2003 Thesis Advisor: Samuel E. Buttrey Second Reader: Robert A...Eriskin Approved by: Samuel E. Buttrey Thesis Advisor Robert A. Koyak Second Reader James N. Eagle Chairman, Department of Operations...1 USS LAKE ERIE USS LAKE CHAMPLAIN Figure 23. Force Maintenance and Material Management Values on Predictor Axis Ships ∆B USS LAKE ERIE 39

  2. Optimizing performance of nonparametric species richness estimators under constrained sampling.

    PubMed

    Rajakaruna, Harshana; Drake, D Andrew R; T Chan, Farrah; Bailey, Sarah A

    2016-10-01

    Understanding the functional relationship between the sample size and the performance of species richness estimators is necessary to optimize limited sampling resources against estimation error. Nonparametric estimators such as Chao and Jackknife demonstrate strong performances, but consensus is lacking as to which estimator performs better under constrained sampling. We explore a method to improve the estimators under such scenario. The method we propose involves randomly splitting species-abundance data from a single sample into two equally sized samples, and using an appropriate incidence-based estimator to estimate richness. To test this method, we assume a lognormal species-abundance distribution (SAD) with varying coefficients of variation (CV), generate samples using MCMC simulations, and use the expected mean-squared error as the performance criterion of the estimators. We test this method for Chao, Jackknife, ICE, and ACE estimators. Between abundance-based estimators with the single sample, and incidence-based estimators with the split-in-two samples, Chao2 performed the best when CV < 0.65, and incidence-based Jackknife performed the best when CV > 0.65, given that the ratio of sample size to observed species richness is greater than a critical value given by a power function of CV with respect to abundance of the sampled population. The proposed method increases the performance of the estimators substantially and is more effective when more rare species are in an assemblage. We also show that the splitting method works qualitatively similarly well when the SADs are log series, geometric series, and negative binomial. We demonstrate an application of the proposed method by estimating richness of zooplankton communities in samples of ballast water. The proposed splitting method is an alternative to sampling a large number of individuals to increase the accuracy of richness estimations; therefore, it is appropriate for a wide range of resource

  3. Estimating thermal performance curves from repeated field observations.

    PubMed

    Childress, Evan S; Letcher, Benjamin H

    2017-03-08

    Estimating thermal performance of organisms is critical for understanding population distributions and dynamics and predicting responses to climate change. Typically, performance curves are estimated using laboratory studies to isolate temperature effects, but other abiotic and biotic factors influence temperature-performance relationships in nature reducing these models' predictive ability. We present a model for estimating thermal performance curves from repeated field observations that includes environmental and individual variation. We fit the model in a Bayesian framework using MCMC sampling, which allowed for estimation of unobserved latent growth while propagating uncertainty. Fitting the model to simulated data varying in sampling design and parameter values demonstrated that the parameter estimates were accurate, precise, and unbiased. Fitting the model to individual growth data from wild trout revealed high out-of-sample predictive ability relative to laboratory-derived models, which produced more biased predictions for field performance. The field-based estimates of thermal maxima were lower than those based on laboratory studies. Under warming temperature scenarios, field-derived performance models predicted stronger declines in body size than laboratory-derived models, suggesting that laboratory-based models may underestimate climate change effects. The presented model estimates true, realized field performance, avoiding assumptions required for applying laboratory-based models to field performance, which should improve estimates of performance under climate change and advance thermal ecology. This article is protected by copyright. All rights reserved.

  4. Estimating thermal performance curves from repeated field observations

    USGS Publications Warehouse

    Childress, Evan; Letcher, Benjamin H.

    2017-01-01

    Estimating thermal performance of organisms is critical for understanding population distributions and dynamics and predicting responses to climate change. Typically, performance curves are estimated using laboratory studies to isolate temperature effects, but other abiotic and biotic factors influence temperature-performance relationships in nature reducing these models' predictive ability. We present a model for estimating thermal performance curves from repeated field observations that includes environmental and individual variation. We fit the model in a Bayesian framework using MCMC sampling, which allowed for estimation of unobserved latent growth while propagating uncertainty. Fitting the model to simulated data varying in sampling design and parameter values demonstrated that the parameter estimates were accurate, precise, and unbiased. Fitting the model to individual growth data from wild trout revealed high out-of-sample predictive ability relative to laboratory-derived models, which produced more biased predictions for field performance. The field-based estimates of thermal maxima were lower than those based on laboratory studies. Under warming temperature scenarios, field-derived performance models predicted stronger declines in body size than laboratory-derived models, suggesting that laboratory-based models may underestimate climate change effects. The presented model estimates true, realized field performance, avoiding assumptions required for applying laboratory-based models to field performance, which should improve estimates of performance under climate change and advance thermal ecology.

  5. Estimating the effect of hospital closure on areawide inpatient hospital costs: a preliminary model and application.

    PubMed Central

    Shepard, D S

    1983-01-01

    A preliminary model is developed for estimating the extent of savings, if any, likely to result from discontinuing a specific inpatient service. By examining the sources of referral to the discontinued service, the model estimates potential demand and how cases will be redistributed among remaining hospitals. This redistribution determines average cost per day in hospitals that receive these cases, relative to average cost per day of the discontinued service. The outflow rate, which measures the proportion of cases not absorbed in other acute care hospitals, is estimated as 30 percent for the average discontinuation. The marginal cost ratio, which relates marginal costs of cases absorbed in surrounding hospitals to the average costs in those hospitals, is estimated as 87 percent in the base case. The model was applied to the discontinuation of all inpatient services in the 75-bed Chelsea Memorial Hospital, near Boston, Massachusetts, using 1976 data. As the precise value of key parameters is uncertain, sensitivity analysis was used to explore a range of values. The most likely result is a small increase ($120,000) in the area's annual inpatient hospital costs, because many patients are referred to more costly teaching hospitals. A similar situation may arise with other urban closures. For service discontinuations to generate savings, recipient hospitals must be low in costs, the outflow rate must be large, and the marginal cost ratio must be low. PMID:6668181

  6. Estimating laser transit anemometry noise performance capabilities

    NASA Technical Reports Server (NTRS)

    Humphreys, William M., Jr.; Hunter, William W., Jr.

    1989-01-01

    A Monte Carlo based LTA (laser transit anemometry) simulation system has been used to perform a detailed evaluation of a set of processing algorithms proposed by Mayo and Smart (1984) for the extraction of two-dimensional flow parameters from LTA data sets collected in a plane normal to the optical axis of the system. The present evaluation includes data ensembles containing 0.0, 5.0, 10.0, and 20.0 percent background noise levels in the constituent correlograms. The results of these evaluations indicate that for turbulence levels of up to 10.0 percent the processing system is able to extract the necessary flow parameters accurately from the LTA data sets. Mean velocity magnitude and flow angle are measurable to within 2.0 percent for turbulence intensity levels of up to 14.0 percent. Standard deviations are measureable to within 10.0 percent over a turbulence range of 3.0-10.0 percent at the same noise levels. These results indicate that the algorithms described have applications in fluid flow surveys.

  7. Preliminary Performance Assessment for Disposal of APT and CLWR/TEF Wastes at SRS

    SciTech Connect

    Wilhite, E.L.

    1998-10-26

    This section provides the descriptive information for understanding the analyses presented in this preliminary performance assessment. This section addresses the approach taken in the PA, provides a general description of the Savannah River Site E-Area low-level waste facility, and discusses the performance criteria used for evaluating performance.

  8. Preliminary Results of Estimating Soil Moisture Over Bare Soil Using Full-Polarimetric ALOS-2 Data

    NASA Astrophysics Data System (ADS)

    Sekertekin, A.; Marangoz, A. M.; Abdikan, S.; Esetlili, M. T.

    2016-10-01

    Synthetic Aperture Radar (SAR) imaging system is one of the most effective way for Earth observation. The aim of this study is to present the preliminary results about estimating soil moisture using L-band Synthetic Aperture Radar (SAR) data. Full-polarimetric (HH, HV, VV, VH) ALOS-2 data, acquired on 22.04.2016 with the incidence angle of 30.4o, were used in the study. Simultaneously with the SAR acquisition, in-situ soil moisture samples over bare agricultural lands were collected and evaluated using gravimetric method. Backscattering coefficients for all polarizations were obtained and linear regression analysis was carried out with in situ moisture measurements. The best correlation coefficient was observed with VV polarization. Cross-polarized backscattering coefficients were not so sensitive to soil moisture content. In the study, it was observed that soil moisture maps can be retrieved with the accuracy about 14% (RMSE).

  9. Path-averaged Rainfall Estimation Using a 27 GHz Microwave Link: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Bijkerk, A.; Stricker, H.; Uijlenhoet, R.

    2003-04-01

    Between May and July 1999 a 27 GHz microwave link has been operated over a 5 km path between the towns of Rhenen and Wageningen in The Netherlands. The instrument, which was built at Eindhoven University of Technology, measures the power arriving at the receiving antenna with a frequency of 18 Hz (i.e. 18 samples per second). During dry weather conditions, it can be used as a microwave scintillometer, i.e. the (turbulent) fluxes of sensible and latent heat can be estimated from the variance of the received power fluctuations. Here we focus on the use of the instrument during rainy conditions, where it can be used to measure the path-integrated attenuation of the microwave signal due to intervening rain between the transmitting and the receiving antenna. Owing to the fact that the specific attenuation at this particular microwave frequency (in dB/km) is closely proportional to the rainfall rate (in mm/h), this instrument is well suited for path-averaged rainfall estimation. This parameter is highly relevant for various hydrological and meteorological applications. We present preliminary analyses for several rainfall events during the mentioned period, where we have compared the path-averaged rainfall estimates from the microwave link with rainfall measurements from a co-located line configuration of six tipping bucket rain gauges.

  10. Preliminary estimates of nanoparticle number emissions from road vehicles in megacity Delhi and associated health impacts.

    PubMed

    Kumar, Prashant; Gurjar, B R; Nagpure, A S; Harrison, Roy M

    2011-07-01

    Rapid urbanisation in developing megacities like Delhi has resulted in an increased number of road vehicles and hence total particle number (ToN) emissions. For the first time, this study presents preliminary estimates of ToN emissions from road vehicles, roadside and ambient ToN concentrations, and exposure related excess deaths in Delhi in current and two future scenarios; business as usual (BAU) and best estimate scenario (BES). Annual ToN emissions are estimated as 1.37 × 10(25) for 2010 which are expected to increase by ∼4 times in 2030-BAU, but to decrease by ∼18 times in 2030-BES. Such reduction is anticipated due to a larger number of compressed natural gas driven vehicles and assumed retrofitting of diesel particulate filters to all diesel vehicles by 2020. Heavy duty vehicles emit the majority (∼65%) of ToN for only ∼4% of total vehicle kilometres traveled in 2010. Their contribution remains dominant under both scenarios in 2030, clearly requiring major mitigation efforts. Roadside and ambient ToN concentrations were up to a factor of 30 and 3 higher to those found in respective European environments. Exposure to ambient ToN concentrations resulted in ∼508, 1888, and 31 deaths per million people in 2010, 2030-BAU and 2030-BES, respectively.

  11. Improving base rate estimation of alcohol misuse in the military: a preliminary report.

    PubMed

    Sheppard, Sean C; Forsyth, John P; Earleywine, Mitch; Hickling, Edward J; Lehrbach, Melissa P

    2013-11-01

    Stigma associated with behavioral health problems in the military pose challenges to accurate base rate estimations. Recent work has highlighted the importance of anonymous assessment methods, yet no study to date has assessed the ability of anonymous self-report measures to mitigate the impact of stigma on honest reporting. This study used the unmatched count technique (UCT), a form of randomized response techniques, to gain information about the accuracy of base rate estimates of alcohol misuse derived via anonymous assessment of Operation Enduring Freedom/Operation Iraqi Freedom active duty service members. A cross-sectional, convenience sample of 184 active-duty service members, recruited via online websites for military populations, provided data on two facets of alcohol misuse (drinking more than intended and feeling the need to reduce use) via traditional self-report and the UCT. The UCT revealed significantly higher rates relative to traditional anonymous assessment for both drinking more than intended (51.9% vs. 23.4%) and feeling the need to reduce use (39.3% vs. 18.2%). These data suggest that anonymity does not completely mitigate the impact of stigma on endorsing behavioral health concerns in the military. Our results, although preliminary, suggest that published rates of alcohol misuse in the military may underestimate the true rates of these concerns. The UCT has significant potential to improve base rate estimation of sensitive behaviors in the military.

  12. Sensitivity analysis and performance estimation of refractivity from clutter techniques

    NASA Astrophysics Data System (ADS)

    Yardim, Caglar; Gerstoft, Peter; Hodgkiss, William S.

    2009-02-01

    Refractivity from clutter (RFC) refers to techniques that estimate the atmospheric refractivity profile from radar clutter returns. A RFC algorithm works by finding the environment whose simulated clutter pattern matches the radar measured one. This paper introduces a procedure to compute RFC estimator performance. It addresses the major factors such as the radar parameters, the sea surface characteristics, and the environment (region, time of the day, season) that affect the estimator performance and formalizes an error metric combining all of these. This is important for applications such as calculating the optimal radar parameters, selecting the best RFC inversion algorithm under a set of conditions, and creating a regional performance map of a RFC system. The performance metric is used to compute the RFC performance of a non-Bayesian evaporation duct estimator. A Bayesian estimator that incorporates meteorological statistics in the inversion is introduced and compared to the non-Bayesian estimator. The performance metric is used to determine the optimal radar parameters of the evaporation duct estimator for six scenarios. An evaporation duct inversion performance map for a S band radar is created for the larger Mediterranean/Arabian Sea region.

  13. DOE passive-solar class A performance-evaluation program: Preliminary results

    NASA Astrophysics Data System (ADS)

    Hunn, B. D.; Turk, W. V.; Wray, W. O.

    1982-08-01

    Elements of the plan for the DOE passive solar class A performance evaluation program are given. A proposed validation methodology, including both analytical and empirical tests, a quantitative definition of validation, minimum data requirements, and a standard reporting format, is outlined. The preliminary testing of this methodology using hourly data from two Class A test facilities is presented. Finally, the collection, analysis, and documentation of preliminary data sets is discussed.

  14. Evaluating the performance of equations for estimating glomerular filtration rate.

    PubMed

    Stevens, Lesley A; Zhang, Yaping; Schmid, Christopher H

    2008-01-01

    Glomerular filtration rate (GFR) is an important indicator of kidney function, critical for detection, evaluation and management of chronic kidney disease (CKD). GFR cannot be practically measured in most clinical or research settings; therefore, estimating equations are used as a primary measure of kidney function. A considerable body of literature now evaluates the performance of GFR estimating equations. The results of these studies are often not comparable, because of variation in GFR measurement methods, endogenous filtration marker assays and tools by which the equations were evaluated. In this article, methods for the evaluation of GFR estimating equations are discussed. Topics addressed include statistical methods used in development and validation of equations; explanation of measures of performance used for evaluation, with focus on distinction between bias, precision and accuracy, and with reference to examples of published evaluations of creatinine- and cystatin C-based equations; explanation of errors in GFR estimates; and challenges and questions in reporting performance of GFR estimating equations.

  15. Next Generation Munitions Handler: Human-Machine Interface and Preliminary Performance Evaluation

    SciTech Connect

    Draper, J.V.; Jansen, J.F.; Pin, F.G.; Rowe, J.C.

    1999-04-25

    The Next Generation Munitions Handler/Advanced Technology Demonstrator (NGMI-VATTD) is a technology demonstrator for the application of an advanced robotic device for re-arming U.S. Air Force (USAF) and U.S. Navy (USN) tactical fighters. It comprises two key hardware components: a heavy-lift dexterous manipulator (HDM) and a nonholonomic mobility platform. The NGMWATTD is capable of lifting weapons up to 4400 kg (2000 lb) and placing them on any weapons rack on existing fighters (including the F-22 Raptor). This report describes the NGMH mission with particular reference to human-machine interfaces. It also describes preliminary testing to garner feedback about the heavy-lift manipulator arm from experienced fighter load crewmen. The purpose of the testing was to provide preliminary information about control system parameters and to gather feed- back from users about manipulator arm functionality. To that end, the Air Force load crewmen interacted with the NGMWATTD in an informal testing session and provided feedback about the performance of the system. Certain con- trol system parameters were changed during the course of the testing and feedback from the participants was used to make a rough estimate of "good" initial operating parameters. Later, formal testing will concentrate within this range to identify optimal operating parameters. User reactions to the HDM were generally positive, All of the USAF personnel were favorably impressed with the capabilities of the system. Fine-tuning operating parameters created a system even more favorably regarded by the load crews. Further adjustment to control system parameters will result in a system that is operationally efficient, easy to use, and well accepted by users.

  16. Potential of preliminary test methods to predict biodegradation performance of petroleum hydrocarbons in soil.

    PubMed

    Aichberger, H; Hasinger, Marion; Braun, Rudolf; Loibner, Andreas P

    2005-03-01

    Preliminary tests at different scales such as degradation experiments (laboratory) in shaking flasks, soil columns and lysimeters as well as in situ respiration tests (field) were performed with soil from two hydrocarbon contaminated sites. Tests have been evaluated in terms of their potential to provide information on feasibility, degradation rates and residual concentration of bioremediation in the vadose zone. Sample size, costs and duration increased with experimental scale in the order shaking flasks - soil columns - lysimeter - in situ respiration tests, only time demand of respiration tests was relatively low. First-order rate constants observed in degradation experiments exhibited significant differences between both, different experimental sizes and different soils. Rates were in line with type and history of contamination at the sites, but somewhat overestimated field rates particularly in small scale experiments. All laboratory experiments allowed an estimation of residual concentrations after remediation. In situ respiration tests were found to be an appropriate pre-testing and monitoring tool for bioventing although residual concentrations cannot be predicted from in situ respiration tests. Moreover, this method does not account for potential limitations that might hamper biodegradation in the longer term but only reflects the actual degradation potential when the test is performed.

  17. Estimation of desmosponge (Porifera, Demospongiae) larval settlement rates from short-term recruitment rates: Preliminary experiments

    NASA Astrophysics Data System (ADS)

    Zea, Sven

    1992-09-01

    During a study of the spatial and temporal patterns of desmosponge (Porifera, Demospongiae) recruitment on rocky and coral reef habitats of Santa Marta, Colombian Caribbean Sea, preliminary attempts were made to estimate actual settlement rates from short-term (1 to a few days) recruitment censuses. Short-term recruitment rates on black, acrylic plastic plates attached to open, non-cryptic substratum by anchor screws were low and variable (0 5 recruits/plate in 1 2 days, sets of n=5 10 plates), but reflected the depth and seasonal trends found using mid-term (1 to a few months) censusing intervals. Moreover, mortality of recruits during 1 2 day intervals was low (0 12%). Thus, short-term censusing intervals can be used to estimate actual settlement rates. To be able to make statistical comparisons, however, it is necessary to increase the number of recruits per census by pooling data of n plates per set, and to have more than one set per site or treatment.

  18. Preliminary experiments to estimate the PE.MA.M (PElagic MArine Mesocosm) offshore behaviour

    NASA Astrophysics Data System (ADS)

    Albani, Marta; Piermattei, Viviana; Stefanì, Chiara; Marcelli, Marco

    2016-04-01

    The phytoplankton community is controlled not only by local environmental conditions but also by physical processes occurring on different temporal and spatial scales. Hydrodynamic local conditions play an important role in marine ecosystems. Several studies have shown that hydrodynamic conditions can influence the phytoplankton settling velocity, vertical and horizontal distribution and formation of cyanobacterial blooms. Mesocosms are useful structures to simulate marine environment at mesoscale resolution; allowing to closely approximate biotic or abiotic parameters of interest directly in nature. In this work an innovative structure named PE.MA.M (PElagic MArine Mesocosm) is presented and tested. Laboratory experiments have been conducted in order to observe seasonal variations of biomass behaviour in two different hydrodynamic conditions: outside as well as whithin the PE.MA.M. We have evaluated whether it is possible to isolate a natural system from external water mass hydrodynamic exchanges and to assume that phytoplankton cells' transition is limited at the net and sea interface. Preliminary experiments test the isolating capacity of the net, to determine the currents' attenuation rate and to estimate the possible PE.MA.M. offshore behaviour. In the first investigation, we monitored the diffusion of phytoplankton cells. The PE.MA.M. exterior and interior were simulated using a plexiglass tank divided into two half-tanks (Aout-Bin) by a septum consisting of a net like a PE.MA.M. The tank was filled up with 10 L of water and only the half-tank Aout was filled up with 10 ml of phytoplankton culture (Clorella sp.). We monitored the chlorophyll concentrations for 24 hours. The two tanks had similar concentrations after 4 hours (2.70322 mg/m³ Aout and 2.37245 mg/m3 Bin) and this constant relationship was maintened until the end of the test. In the second investigation we used clod cards to measure water motions.We conducted two experiments within tank, the first

  19. Analytical Approach for Estimating Preliminary Mass of ARES I Crew Launch Vehicle Upper Stage Structural Components

    NASA Technical Reports Server (NTRS)

    Aggarwal, Pravin

    2007-01-01

    electrical power functions to other Elements of the CLV, is included as secondary structure. The MSFC has an overall responsibility for the integrated US element as well as structural design an thermal control of the fuel tanks, intertank, interstage, avionics, main propulsion system, Reaction Control System (RCS) for both the Upper Stage and the First Stage. MSFC's Spacecraft and Vehicle Department, Structural and Analysis Design Division is developing a set of predicted mass of these elements. This paper details the methodology, criterion and tools used for the preliminary mass predictions of the upper stage structural assembly components. In general, weight of the cylindrical barrel sections are estimated using the commercial code Hypersizer, whereas, weight of the domes are developed using classical solutions. HyperSizer is software that performs automated structural analysis and sizing optimization based on aerospace methods for strength, stability, and stiffness. Analysis methods range from closed form, traditional hand calculations repeated every day in industry to more advanced panel buckling algorithms. Margin-of-safety reporting for every potential failure provides the engineer with a powerful insight into the structural problem. Optimization capabilities include finding minimum weight panel or beam concepts, material selections, cross sectional dimensions, thicknesses, and lay-ups from a library of 40 different stiffened and sandwich designs and a database of composite, metallic, honeycomb, and foam materials. Multiple different concepts (orthogrid, isogrid, and skin stiffener) were run for multiple loading combinations of ascent design load with and with out tank pressure as well as proof pressure condition. Subsequently, selected optimized concept obtained from Hypersizer runs was translated into a computer aid design (CAD) model to account for the wall thickness tolerance, weld land etc for developing the most probable weight of the components. The flow diram

  20. A preliminary structural analysis of space-base living quarters modules to verify a weight-estimating technique

    NASA Technical Reports Server (NTRS)

    Grissom, D. S.; Schneider, W. C.

    1971-01-01

    The determination of a base line (minimum weight) design for the primary structure of the living quarters modules in an earth-orbiting space base was investigated. Although the design is preliminary in nature, the supporting analysis is sufficiently thorough to provide a reasonably accurate weight estimate of the major components that are considered to comprise the structural weight of the space base.

  1. AMT-200S Motor Glider Parameter and Performance Estimation

    NASA Technical Reports Server (NTRS)

    Taylor, Brian R.

    2011-01-01

    Parameter and performance estimation of an instrumented motor glider was conducted at the National Aeronautics and Space Administration Dryden Flight Research Center in order to provide the necessary information to create a simulation of the aircraft. An output-error technique was employed to generate estimates from doublet maneuvers, and performance estimates were compared with results from a well-known flight-test evaluation of the aircraft in order to provide a complete set of data. Aircraft specifications are given along with information concerning instrumentation, flight-test maneuvers flown, and the output-error technique. Discussion of Cramer-Rao bounds based on both white noise and colored noise assumptions is given. Results include aerodynamic parameter and performance estimates for a range of angles of attack.

  2. Preliminary flight evaluation of an engine performance optimization algorithm

    NASA Technical Reports Server (NTRS)

    Lambert, H. H.; Gilyard, G. B.; Chisholm, J. D.; Kerr, L. J.

    1991-01-01

    A performance seeking control (PSC) algorithm has undergone initial flight test evaluation in subsonic operation of a PW 1128 engined F-15. This algorithm is designed to optimize the quasi-steady performance of an engine for three primary modes: (1) minimum fuel consumption; (2) minimum fan turbine inlet temperature (FTIT); and (3) maximum thrust. The flight test results have verified a thrust specific fuel consumption reduction of 1 pct., up to 100 R decreases in FTIT, and increases of as much as 12 pct. in maximum thrust. PSC technology promises to be of value in next generation tactical and transport aircraft.

  3. Performance Analysis of the Least-Squares Estimator in Astrometry

    NASA Astrophysics Data System (ADS)

    Lobos, Rodrigo A.; Silva, Jorge F.; Mendez, Rene A.; Orchard, Marcos

    2015-11-01

    We characterize the performance of the widely-used least-squares estimator in astrometry in terms of a comparison with the Cramer-Rao lower variance bound. In this inference context the performance of the least-squares estimator does not offer a closed-form expression, but a new result is presented (Theorem 1) where both the bias and the mean-square-error of the least-squares estimator are bounded and approximated analytically, in the latter case in terms of a nominal value and an interval around it. From the predicted nominal value we analyze how efficient is the least-squares estimator in comparison with the minimum variance Cramer-Rao bound. Based on our results, we show that, for the high signal-to-noise ratio regime, the performance of the least-squares estimator is significantly poorer than the Cramer-Rao bound, and we characterize this gap analytically. On the positive side, we show that for the challenging low signal-to-noise regime (attributed to either a weak astronomical signal or a noise-dominated condition) the least-squares estimator is near optimal, as its performance asymptotically approaches the Cramer-Rao bound. However, we also demonstrate that, in general, there is no unbiased estimator for the astrometric position that can precisely reach the Cramer-Rao bound. We validate our theoretical analysis through simulated digital-detector observations under typical observing conditions. We show that the nominal value for the mean-square-error of the least-squares estimator (obtained from our theorem) can be used as a benchmark indicator of the expected statistical performance of the least-squares method under a wide range of conditions. Our results are valid for an idealized linear (one-dimensional) array detector where intra-pixel response changes are neglected, and where flat-fielding is achieved with very high accuracy.

  4. Preliminary performance assessment of computer automated facial approximations using computed tomography scans of living individuals.

    PubMed

    Parks, Connie L; Richard, Adam H; Monson, Keith L

    2013-12-10

    ReFace (Reality Enhancement Facial Approximation by Computational Estimation) is a computer-automated facial approximation application jointly developed by the Federal Bureau of Investigation and GE Global Research. The application derives a statistically based approximation of a face from a unidentified skull using a dataset of ~400 human head computer tomography (CT) scans of living adult American individuals from four ancestry groups: African, Asian, European and Hispanic (self-identified). To date only one unpublished subjective recognition study has been conducted using ReFace approximations. It indicated that approximations produced by ReFace were recognized above chance rates (10%). This preliminary study assesses: (i) the recognizability of five ReFace approximations; (ii) the recognizability of CT-derived skin surface replicas of the same individuals whose skulls were used to create the ReFace approximations; and (iii) the relationship between recognition performance and resemblance ratings of target individuals. All five skin surface replicas were recognized at rates statistically significant above chance (22-50%). Four of five ReFace approximations were recognized above chance (5-18%), although with statistical significance only at the higher rate. Such results suggest reconsideration of the usefulness of the type of output format utilized in this study, particularly in regard to facial approximations employed as a means of identifying unknown individuals.

  5. Performance Assessment Register. Working Group 12 Preliminary Report

    DTIC Science & Technology

    1988-08-01

    reported to the member nations and the NATO Authorities through the AGARD series of publications of which this is one. Participation in AGARD activities ...stressors; its activities , however, may also be of interest to those who wish to assess individual differences in information-processing capabilities...sent a simple questionnaire to researchers in his own country wiio are active in performance testing. The responses have been collated in the form of

  6. Personality Factors Affecting Pilot Combat Performance: A Preliminary Investigation

    DTIC Science & Technology

    1997-09-01

    collected by personnel from Metrica , Inc., under Contract F33615-91-D-0010 (Delivery Order 0005) sponsored by the Air Force Armstrong Laboratory. The...authors would like to thank ’their colleagues at Metrica for their contributions to . this effort; in particular, Mr John Quebe and Mr Martin Dittmar...aircrew combat performance. San Antonio TX: Metrica Inc. 7 . Dolgin, D.L., & Gibb, G.D. (1988). Personality assessment in aviator selection (NAMRL

  7. Astrometric telescope facility. Preliminary systems definition study. Volume 3: Cost estimate

    NASA Technical Reports Server (NTRS)

    Sobeck, Charlie (Editor)

    1987-01-01

    The results of the Astrometric Telescope Facility (ATF) Preliminary System Definition Study conducted in the period between March and September 1986 are described. The main body of the report consists primarily of the charts presented at the study final review which was held at NASA Ames Research Center on July 30 and 31, 1986. The charts have been revised to reflect the results of that review. Explanations for the charts are provided on the adjoining pages where required. Note that charts which have been changed or added since the review are dated 10/1/86; unchanged charts carry the review date 7/30/86. In addition, a narrative summary is presented of the study results and two appendices. The first appendix is a copy of the ATF Characteristics and Requirements Document generated as part of the study. The second appendix shows the inputs to the Space Station Mission Requirements Data Base submitted in May 1986. The report is issued in three volumes. Volume 1 contains an executive summary of the ATF mission, strawman design, and study results. Volume 2 contains the detailed study information. Volume 3 has the ATF cost estimate, and will have limited distribution.

  8. Estimation of Ultrafilter Performance Based on Characterization Data

    SciTech Connect

    Peterson, Reid A.; Geeting, John GH; Daniel, Richard C.

    2007-08-02

    Due to limited availability of test data with actual waste samples, a method was developed to estimate expected filtration performance based on physical characterization data for the Hanford Waste Treatment and Immobilization Plant. A test with simulated waste was analyzed to demonstrate that filtration of this class of waste is consistent with a concentration polarization model. Subsequently, filtration data from actual waste samples were analyzed to demonstrate that centrifuged solids concentrations provide a reasonable estimate of the limiting concentration for filtration.

  9. Preliminary Transportation, Aging and Disposal Canister System Performance Specification

    SciTech Connect

    C.A Kouts

    2006-11-22

    This document provides specifications for selected system components of the Transportation, Aging and Disposal (TAD) canister-based system. A list of system specified components and ancillary components are included in Section 1.2. The TAD canister, in conjunction with specialized overpacks will accomplish a number of functions in the management and disposal of spent nuclear fuel. Some of these functions will be accomplished at purchaser sites where commercial spent nuclear fuel (CSNF) is stored, and some will be performed within the Office of Civilian Radioactive Waste Management (OCRWM) transportation and disposal system. This document contains only those requirements unique to applications within Department of Energy's (DOE's) system. DOE recognizes that TAD canisters may have to perform similar functions at purchaser sites. Requirements to meet reactor functions, such as on-site dry storage, handling, and loading for transportation, are expected to be similar to commercially available canister-based systems. This document is intended to be referenced in the license application for the Monitored Geologic Repository (MGR). As such, the requirements cited herein are needed for TAD system use in OCRWM's disposal system. This document contains specifications for the TAD canister, transportation overpack and aging overpack. The remaining components and equipment that are unique to the OCRWM system or for similar purchaser applications will be supplied by others.

  10. A Preliminary Analysis of LANDSAT-4 Thematic Mapper Radiometric Performance

    NASA Technical Reports Server (NTRS)

    Justice, C.; Fusco, L.; Mehl, W.

    1985-01-01

    The NASA raw (BT) product, the radiometrically corrected (AT) product, and the radiometrically and geometrically corrected (PT) product of a TM scene were analyzed examine the frequency distribution of the digital data; the statistical correlation between the bands; and the variability between the detectors within a band. The analyses were performed on a series of image subsets from the full scence. Results are presented from one 1024 c 1024 pixel subset of Realfoot Lake, Tennessee which displayed a representative range of ground conditions and cover types occurring within the full frame image. From this cursory examination of one of the first seven channel TM data sets, it would appear that the radiometric performance of the system is most satisfactory and largely meets pre-launch specifications. Problems were noted with Band 5 Detector 3 and Band 2 Detector 4. Differences were observed between forward and reverse scan detector responses both for the BT and AT products. No systematic variations were observed between odd and even detectors.

  11. Cognitive Performance in Suicidal Depressed Elderly: Preliminary Report

    PubMed Central

    Dombrovski, Alexandre Y.; Butters, Meryl A.; Reynolds, Charles F.; Houck, Patricia R.; Clark, Luke; Mazumdar, Sati; Szanto, Katalin

    2009-01-01

    Objective Deficits in executive functions may play an important role in late-life suicide; however the association is understudied. This study examined cognitive function in general and executive functioning specifically in depressed elderly with and without suicidal ideation and attempts. Design Case-control study. Setting University-affiliated psychiatric hospital. Participants We compared 32 suicidal depressed participants aged 60 and older with 32 non-suicidal depressed participants equated for age, education, and gender. Measurements We assessed global cognitive function and executive function with the Dementia Rating Scale (DRS) and the Executive Interview (EXIT25), respectively. Results Suicidal and non-suicidal depressed groups were comparable in terms of severity of depression and burden of physical illness. Suicidal participants performed worse on the EXIT25, and on the DRS total scale, as well as on Memory and Attention subscales. The differences were not explained by the presence of dementia, substance use, medication exposure, or brain injury from suicide attempts. Conclusions Poor performance on tests of executive function, attention, and memory is associated with suicidal behavior in late-life depression. PMID:18239196

  12. Advanced Analysis of Finger-Tapping Performance: A Preliminary Study

    PubMed Central

    Barut, Çağatay; Kızıltan, Erhan; Gelir, Ethem; Köktürk, Fürüzan

    2013-01-01

    Background: The finger-tapping test is a commonly employed quantitative assessment tool used to measure motor performance in the upper extremities. This task is a complex motion that is affected by external stimuli, mood and health status. The complexity of this task is difficult to explain with a single average intertap-interval value (time difference between successive tappings) which only provides general information and neglects the temporal effects of the aforementioned factors. Aims: This study evaluated the time course of average intertap-interval values and the patterns of variation in both the right and left hands of right-handed subjects using a computer-based finger-tapping system. Study Design: Cross sectional study. Methods: Thirty eight male individuals aged between 20 and 28 years (Mean±SD = 22.24±1.65) participated in the study. Participants were asked to perform single-finger-tapping test for 10 seconds of test period. Only the results of right-handed (RH) 35 participants were considered in this study. The test records the time of tapping and saves data as the time difference between successive tappings for further analysis. The average number of tappings and the temporal fluctuation patterns of the intertap-intervals were calculated and compared. The variations in the intertap-interval were evaluated with the best curve fit method. Results: An average tapping speed or tapping rate can reliably be defined for a single-finger tapping test by analysing the graphically presented data of the number of tappings within the test period. However, a different presentation of the same data, namely the intertap-interval values, shows temporal variation as the number of tapping increases. Curve fitting applications indicate that the variation has a biphasic nature. Conclusion: The measures obtained in this study reflect the complex nature of the finger-tapping task and are suggested to provide reliable information regarding hand performance. Moreover, the

  13. Hydronic radiant cooling: Overview and preliminary performance assessment

    SciTech Connect

    Feustel, H.E.

    1993-05-01

    A significant amount of electrical energy used to cool non-residential buildings is drawn by the fans used to transport the cool air through the thermal distribution system. Hydronic systems reduce the amount of air transported through the building by separating ventilation and thermal conditioning. Due to the physical properties of water, hydronic distribution systems can transport a given amount of thermal energy using less than 5% of the otherwise necessary fan energy. This savings alone significantly reduces the energy consumption and especially the peak power requirement This survey clearly shows advantages for radiant cooling in combination with hydronic thermal distribution systems in comparison with the All-Air Systems commonly used in California. The report describes a literature survey on the system's development, thermal comfort issues, and cooling performance. The cooling power potential and the cooling power requirement are investigated for several California climates. Peak-power requirement is compared for hydronic radiant cooling and conventional All-Air-Systems.

  14. Methodology for the Preliminary Design of High Performance Schools in Hot and Humid Climates

    ERIC Educational Resources Information Center

    Im, Piljae

    2009-01-01

    A methodology to develop an easy-to-use toolkit for the preliminary design of high performance schools in hot and humid climates was presented. The toolkit proposed in this research will allow decision makers without simulation knowledge easily to evaluate accurately energy efficient measures for K-5 schools, which would contribute to the…

  15. Methodology for the Preliminary Design of High Performance Schools in Hot and Humid Climates

    ERIC Educational Resources Information Center

    Im, Piljae

    2009-01-01

    A methodology to develop an easy-to-use toolkit for the preliminary design of high performance schools in hot and humid climates was presented. The toolkit proposed in this research will allow decision makers without simulation knowledge easily to evaluate accurately energy efficient measures for K-5 schools, which would contribute to the…

  16. Hydronic radiant cooling: Overview and preliminary performance assessment

    SciTech Connect

    Feustel, H.E.

    1993-05-01

    A significant amount of electrical energy used to cool non-residential buildings is drawn by the fans used to transport the cool air through the thermal distribution system. Hydronic systems reduce the amount of air transported through the building by separating ventilation and thermal conditioning. Due to the physical properties of water, hydronic distribution systems can transport a given amount of thermal energy using less than 5% of the otherwise necessary fan energy. This savings alone significantly reduces the energy consumption and especially the peak power requirement This survey clearly shows advantages for radiant cooling in combination with hydronic thermal distribution systems in comparison with the All-Air Systems commonly used in California. The report describes a literature survey on the system`s development, thermal comfort issues, and cooling performance. The cooling power potential and the cooling power requirement are investigated for several California climates. Peak-power requirement is compared for hydronic radiant cooling and conventional All-Air-Systems.

  17. Preliminary Investigations of HE Performance Characterization Using SWIFT

    NASA Astrophysics Data System (ADS)

    Murphy, Michael; Johnson, Carl

    2013-06-01

    Initial pseudo-aquarium experimentation is underway to assess the utility of using the shock wave image framing technique (SWIFT) to characterize HE performance on detonator length and time scales. SWIFT is employed to directly visualize shock waves driven into polymethylmethacrylate (PMMA) samples through detonation interaction in pseudo-aquarium test geometries. Columns of XTX 8004, an extrudable RDX-based high explosive, are either cured directly within PMMA dynamic witness plates or within confinement tubes of different materials with varying shock impedances that are then embedded within PMMA. For current experiments, the SWIFT system records 16-frame image sequences using 175 ns inter-frame delays to directly visualize the evolution of lead shock-front geometries as they are driven radially into PMMA by the detonating XTX column. Standard aquarium-test analysis is employed to calculate shock pressure evolution within PMMA, and detonation wave velocities are accurately calculated from the time-resolved images as well. The SWIFT system and numerous pseudo-aquarium experimental results will be presented and discussed.

  18. Preliminary estimation of isotopic inventories of 2000 MWt ABR (revision 1).

    SciTech Connect

    Kim, T. K.; Yang, W. S.; Nuclear Engineering Division

    2008-06-16

    The isotopic inventories of a 2000 MWt Advanced Burner Reactor (ABR) core have been estimated to support the ABR accident analysis to be reported in the Appendix D of the Programmatic Environmental Impact Statement (PEIS). Based on the Super-PRISM design, a preliminary core design of 2000 MWt ABR was developed to achieve a one-year cycle length with 3-batch fuel management scheme. For a bounding estimation of transuranics (TRU) inventory, a low TRU conversion ratio ({approx}0.3) was targeted to increase the TRU enrichment. By changing the fuel compositions, isotopic inventories of mass and radioactivity were evaluated for four different core configurations: recycled metal fuel core, recycled oxide fuel core, startup metal fuel core, and startup oxide fuel core. For recycled cores, the TRU recovered from ABR spent fuel was used as the primary TRU feed, and the TRU recovered from 10-year cooled light water reactor spent fuel was used as the makeup TRU feed. For startup cores, weapons-grade plutonium was used as TRU feed without recycling ABR spent fuel. It was also assumed that a whole batch of discharged fuel assemblies is stored in the in-vessel storage for an entire irradiation cycle. For both metal and oxide fuel cores, the estimated TRU mass at beginning of equilibrium cycle (BOEC), including spent fuel TRU stored in the in-vessel storage, was about 8.5-8.7 MT for the recycled cores and 5.2 MT for the startup cores. Since a similar power was generated, the fission product mass are comparable for all four cores: 1.4 MT at BOEC and about 2.0 MT at end of equilibrium cycle (EOEC). Total radioactivity at BOEC is about 8.2 x 10{sup 8} curies in recycled cores and about 6.9 x 10{sup 8} curies in startup cores, and increases to about 1.1 x 10{sup 10} curies at EOEC for all four cases. Fission products are the dominant contributor (more than 80%) to the total radioactivity at EOEC for all four cases, but the fission product radioactivity decreases by 79% after one

  19. Resource Estimation in High Performance Medical Image Computing

    PubMed Central

    Banalagay, Rueben; Covington, Kelsie Jade; Wilkes, D.M.

    2015-01-01

    Medical imaging analysis processes often involve the concatenation of many steps (e.g., multi-stage scripts) to integrate and realize advancements from image acquisition, image processing, and computational analysis. With the dramatic increase in data size for medical imaging studies (e.g., improved resolution, higher throughput acquisition, shared databases), interesting study designs are becoming intractable or impractical on individual workstations and servers. Modern pipeline environments provide control structures to distribute computational load in high performance computing (HPC) environments. However, high performance computing environments are often shared resources, and scheduling computation across these resources necessitates higher level modeling of resource utilization. Submission of ‘jobs’ requires an estimate of the CPU runtime and memory usage. The resource requirements for medical image processing algorithms are difficult to predict since the requirements can vary greatly between different machines, different execution instances, and different data inputs. Poor resource estimates can lead to wasted resources in high performance environments due to incomplete executions and extended queue wait times. Hence, resource estimation is becoming a major hurdle for medical image processing algorithms to efficiently leverage high performance computing environments. Herein, we present our implementation of a resource estimation system to overcome these difficulties and ultimately provide users with the ability to more efficiently utilize high performance computing resources. PMID:24906466

  20. Resource estimation in high performance medical image computing.

    PubMed

    Banalagay, Rueben; Covington, Kelsie Jade; Wilkes, D M; Landman, Bennett A

    2014-10-01

    Medical imaging analysis processes often involve the concatenation of many steps (e.g., multi-stage scripts) to integrate and realize advancements from image acquisition, image processing, and computational analysis. With the dramatic increase in data size for medical imaging studies (e.g., improved resolution, higher throughput acquisition, shared databases), interesting study designs are becoming intractable or impractical on individual workstations and servers. Modern pipeline environments provide control structures to distribute computational load in high performance computing (HPC) environments. However, high performance computing environments are often shared resources, and scheduling computation across these resources necessitates higher level modeling of resource utilization. Submission of 'jobs' requires an estimate of the CPU runtime and memory usage. The resource requirements for medical image processing algorithms are difficult to predict since the requirements can vary greatly between different machines, different execution instances, and different data inputs. Poor resource estimates can lead to wasted resources in high performance environments due to incomplete executions and extended queue wait times. Hence, resource estimation is becoming a major hurdle for medical image processing algorithms to efficiently leverage high performance computing environments. Herein, we present our implementation of a resource estimation system to overcome these difficulties and ultimately provide users with the ability to more efficiently utilize high performance computing resources.

  1. Preliminary estimates of annual agricultural pesticide use for counties of the conterminous United States, 2010-11

    USGS Publications Warehouse

    Baker, Nancy T.; Stone, Wesley W.

    2013-01-01

    This report provides preliminary estimates of annual agricultural use of 374 pesticide compounds in counties of the conterminous United States in 2010 and 2011, compiled by means of methods described in Thelin and Stone (2013). U.S. Department of Agriculture (USDA) county-level data for harvested-crop acreage were used in conjunction with proprietary Crop Reporting District (CRD)-level pesticide-use data to estimate county-level pesticide use. Estimated pesticide use (EPest) values were calculated with both the EPest-high and EPest-low methods. The distinction between the EPest-high method and the EPest-low method is that there are more counties with estimated pesticide use for EPest-high compared to EPest-low, owing to differing assumptions about missing survey data (Thelin and Stone, 2013). Preliminary estimates in this report will be revised upon availability of updated crop acreages in the 2012 Agricultural Census, to be published by the USDA in 2014. In addition, estimates for 2008 and 2009 previously published by Stone (2013) will be updated subsequent to the 2012 Agricultural Census release. Estimates of annual agricultural pesticide use are provided as downloadable, tab-delimited files, which are organized by compound, year, state Federal Information Processing Standard (FIPS) code, county FIPS code, and kg (amount in kilograms).

  2. The burden of chronic mercury intoxication in artisanal small-scale gold mining in Zimbabwe: data availability and preliminary estimates.

    PubMed

    Steckling, Nadine; Bose-O'Reilly, Stephan; Pinheiro, Paulo; Plass, Dietrich; Shoko, Dennis; Drasch, Gustav; Bernaudat, Ludovic; Siebert, Uwe; Hornberg, Claudia

    2014-12-13

    Artisanal small-scale gold mining (ASGM) is a poverty-driven activity practiced in over 70 countries worldwide. Zimbabwe is amongst the top ten countries using large quantities of mercury to extract gold from ore. This analysis was performed to check data availability and derive a preliminary estimate of disability-adjusted life years (DALYs) due to mercury use in ASGM in Zimbabwe. Cases of chronic mercury intoxication were identified following an algorithm using mercury-related health effects and mercury in human specimens. The sample prevalence amongst miners and controls (surveyed by the United Nations Industrial Development Organization in 2004 and the University of Munich in 2006) was determined and extrapolated to the entire population of Zimbabwe. Further epidemiological and demographic data were taken from the literature and missing data modeled with DisMod II to quantify DALYs using the methods from the Global Burden of Disease (GBD) 2004 update published by the World Health Organization (WHO). While there was no disability weight (DW) available indicating the relative disease severity of chronic mercury intoxication, the DW of a comparable disease was assigned by following the criteria 1) chronic condition, 2) triggered by a substance, and 3) causing similar health symptoms. Miners showed a sample prevalence of 72% while controls showed no cases of chronic mercury intoxication. Data availability is very limited why it was necessary to model data and make assumptions about the number of exposed population, the definition of chronic mercury intoxication, DW, and epidemiology. If these assumptions hold, the extrapolation would result in around 95,400 DALYs in Zimbabwe's total population in 2004. This analysis provides a preliminary quantification of the mercury-related health burden from ASGM based on the limited data available. If the determined assumptions hold, chronic mercury intoxication is likely to have been one of the top 20 hazards for population

  3. Estimating endogenous changes in task performance from EEG

    PubMed Central

    Touryan, Jon; Apker, Gregory; Lance, Brent J.; Kerick, Scott E.; Ries, Anthony J.; McDowell, Kaleb

    2014-01-01

    Brain wave activity is known to correlate with decrements in behavioral performance as individuals enter states of fatigue, boredom, or low alertness.Many BCI technologies are adversely affected by these changes in user state, limiting their application and constraining their use to relatively short temporal epochs where behavioral performance is likely to be stable. Incorporating a passive BCI that detects when the user is performing poorly at a primary task, and adapts accordingly may prove to increase overall user performance. Here, we explore the potential for extending an established method to generate continuous estimates of behavioral performance from ongoing neural activity; evaluating the extended method by applying it to the original task domain, simulated driving; and generalizing the method by applying it to a BCI-relevant perceptual discrimination task. Specifically, we used EEG log power spectra and sequential forward floating selection (SFFS) to estimate endogenous changes in behavior in both a simulated driving task and a perceptual discrimination task. For the driving task the average correlation coefficient between the actual and estimated lane deviation was 0.37 ± 0.22 (μ ± σ). For the perceptual discrimination task we generated estimates of accuracy, reaction time, and button press duration for each participant. The correlation coefficients between the actual and estimated behavior were similar for these three metrics (accuracy = 0.25 ± 0.37, reaction time = 0.33 ± 0.23, button press duration = 0.36 ± 0.30). These findings illustrate the potential for modeling time-on-task decrements in performance from concurrent measures of neural activity. PMID:24994968

  4. Solar pond performance estimation, engineering design, and construction experience

    SciTech Connect

    Hull, J.R.

    1983-12-11

    A solar pond is a low-cost solar collector and storage device for low-temperature (less than 110/sup 0/C) heat. However, there are many design and construction details that must be considered to obtain the optimum efficiencies necessary to achieve economical performance. Several of these considerations, as well as a brief description of mathematical models for estimating performance, are discussed in this paper.

  5. Model-based approach for elevator performance estimation

    NASA Astrophysics Data System (ADS)

    Esteban, E.; Salgado, O.; Iturrospe, A.; Isasa, I.

    2016-02-01

    In this paper, a dynamic model for an elevator installation is presented in the state space domain. The model comprises both the mechanical and the electrical subsystems, including the electrical machine and a closed-loop field oriented control. The proposed model is employed for monitoring the condition of the elevator installation. The adopted model-based approach for monitoring employs the Kalman filter as an observer. A Kalman observer estimates the elevator car acceleration, which determines the elevator ride quality, based solely on the machine control signature and the encoder signal. Finally, five elevator key performance indicators are calculated based on the estimated car acceleration. The proposed procedure is experimentally evaluated, by comparing the key performance indicators calculated based on the estimated car acceleration and the values obtained from actual acceleration measurements in a test bench. Finally, the proposed procedure is compared with the sliding mode observer.

  6. Data used in preliminary performance assessment of the Waste Isolation Pilot Plant (1990)

    SciTech Connect

    Rechard, R.P ); Luzzolino, H. ); Sandha, J.S. )

    1990-12-01

    This report documents the data available as of August 1990 and used by the Performance Assessment Division of Sandia National Laboratories in its December 1990 preliminary performance assessment of the Waste Isolation Pilot Plant (WIPP). Parameter values are presented in table form for the geologic subsystem, engineered barriers, borehole flow properties, climate variability, and intrusion characteristics. Sources for the data and a brief discussion of each parameter are provided. 101 refs., 72 figs., 21 tabs.

  7. Estimating Costs for Development of Candidate Performance Evaluation Procedures.

    ERIC Educational Resources Information Center

    Payne, David A.

    This paper contains cost unit tables and instructions for their use in estimating the total cost of evaluating a given instructional objective or group of objectives. Included is a list of analytical procedures to be followed in the development of any device to evaluate student performance, (e.g., a unit exam in child development or an attitude…

  8. Hip fracture risk estimation based on principal component analysis of QCT atlas: a preliminary study

    NASA Astrophysics Data System (ADS)

    Li, Wenjun; Kornak, John; Harris, Tamara; Lu, Ying; Cheng, Xiaoguang; Lang, Thomas

    2009-02-01

    We aim to capture and apply 3-dimensional bone fragility features for fracture risk estimation. Using inter-subject image registration, we constructed a hip QCT atlas comprising 37 patients with hip fractures and 38 age-matched controls. In the hip atlas space, we performed principal component analysis to identify the principal components (eigen images) that showed association with hip fracture. To develop and test a hip fracture risk model based on the principal components, we randomly divided the 75 QCT scans into two groups, one serving as the training set and the other as the test set. We applied this model to estimate a fracture risk index for each test subject, and used the fracture risk indices to discriminate the fracture patients and controls. To evaluate the fracture discrimination efficacy, we performed ROC analysis and calculated the AUC (area under curve). When using the first group as the training group and the second as the test group, the AUC was 0.880, compared to conventional fracture risk estimation methods based on bone densitometry, which had AUC values ranging between 0.782 and 0.871. When using the second group as the training group, the AUC was 0.839, compared to densitometric methods with AUC values ranging between 0.767 and 0.807. Our results demonstrate that principal components derived from hip QCT atlas are associated with hip fracture. Use of such features may provide new quantitative measures of interest to osteoporosis.

  9. Measures of performance in nonlinear estimation tasks: prediction of estimation performance at low signal-to-noise ratio

    NASA Astrophysics Data System (ADS)

    Müller, Stefan P.; Abbey, Craig K.; Rybicki, Frank J.; Moore, Stephen C.; Foley Kijewski, Marie

    2005-08-01

    Maximum-likelihood (ML) estimation is an established paradigm for the assessment of imaging system performance in nonlinear quantitation tasks. At high signal-to-noise ratio (SNR), ML estimates are asymptotically Gaussian-distributed, unbiased and efficient, thereby attaining the Cramer-Rao bound (CRB). Therefore, at high SNR the CRB is useful as a predictor of the variance of ML estimates and, consequently, as a basis for measures of estimation performance. At low SNR, however, the achievable parameter variances are often substantially larger than the CRB and the estimates are no longer Gaussian-distributed. These departures imply that inference about the estimates that is based on the CRB and the assumption of a normal distribution will not be valid. We have found previously that for some tasks these effects arise at noise levels considered clinically acceptable. We have derived the mathematical relationship between a new measure, χ2pdf-ML, and the expected probability density of the ML estimates, and have justified the use of χ2pdf-ML-isocontours in parameter space to describe the ML estimates. We validated this approach by simulation experiments using spherical objects imaged with a Gaussian point spread function. The parameters, activity concentration and size, were estimated simultaneously by ML, and variances and covariances calculated over 1000 replications per condition from 3D image volumes and from 2D tomographic projections of the same object. At low SNR, where the CRB is no longer achievable, χ2pdf-ML-isocontours provide a robust prediction of the distribution of the ML estimates. At high SNR, the χ2pdf-ML-isocontours asymptotically approach the analogous χ2pdf-F-contours derived from the Fisher information matrix. The χ2pdf-ML model appears to be suitable for characterization of the influence of the noise level and characteristics, the task, and the object on the shape of the probability density of the ML estimates at low SNR. Furthermore, it

  10. Preliminary Estimation of Deoxynivalenol Excretion through a 24 h Pilot Study

    PubMed Central

    Rodríguez-Carrasco, Yelko; Mañes, Jordi; Berrada, Houda; Font, Guillermina

    2015-01-01

    A duplicate diet study was designed to explore the occurrence of 15 Fusarium mycotoxins in the 24 h-diet consumed by one volunteer as well as the levels of mycotoxins in his 24 h-collected urine. The employed methodology involved solvent extraction at high ionic strength followed by dispersive solid phase extraction and gas chromatography determination coupled to mass spectrometry in tandem. Satisfactory results in method performance were achieved. The method’s accuracy was in a range of 68%–108%, with intra-day relative standard deviation and inter-day relative standard deviation lower than 12% and 15%, respectively. The limits of quantitation ranged from 0.1 to 8 µg/Kg. The matrix effect was evaluated and matrix-matched calibrations were used for quantitation. Only deoxynivalenol (DON) was quantified in both food and urine samples. A total DON daily intake amounted to 49.2 ± 5.6 µg whereas DON daily excretion of 35.2 ± 4.3 µg was determined. DON daily intake represented 68.3% of the established DON provisional maximum tolerable daily intake (PMTDI). Valuable preliminary information was obtained as regards DON excretion and needs to be confirmed in large-scale monitoring studies. PMID:25723325

  11. Quantitative assessment of the microbial risk of leafy greens from farm to consumption: preliminary framework, data, and risk estimates.

    PubMed

    Danyluk, Michelle D; Schaffner, Donald W

    2011-05-01

    This project was undertaken to relate what is known about the behavior of Escherichia coli O157:H7 under laboratory conditions and integrate this information to what is known regarding the 2006 E. coli O157:H7 spinach outbreak in the context of a quantitative microbial risk assessment. The risk model explicitly assumes that all contamination arises from exposure in the field. Extracted data, models, and user inputs were entered into an Excel spreadsheet, and the modeling software @RISK was used to perform Monte Carlo simulations. The model predicts that cut leafy greens that are temperature abused will support the growth of E. coli O157:H7, and populations of the organism may increase by as much a 1 log CFU/day under optimal temperature conditions. When the risk model used a starting level of -1 log CFU/g, with 0.1% of incoming servings contaminated, the predicted numbers of cells per serving were within the range of best available estimates of pathogen levels during the outbreak. The model predicts that levels in the field of -1 log CFU/g and 0.1% prevalence could have resulted in an outbreak approximately the size of the 2006 E. coli O157:H7 outbreak. This quantitative microbial risk assessment model represents a preliminary framework that identifies available data and provides initial risk estimates for pathogenic E. coli in leafy greens. Data gaps include retail storage times, correlations between storage time and temperature, determining the importance of E. coli O157:H7 in leafy greens lag time models, and validation of the importance of cross-contamination during the washing process.

  12. Gas geochemistry and preliminary CO2 output estimation from the island of Kos (Greece)

    NASA Astrophysics Data System (ADS)

    D'Alessandro, Walter; Daskalopoulou, Kyriaki; Calabrese, Sergio; Longo, Manfredi; Kyriakopoulos, Konstantinos; Gagliano, Antonina Lisa

    2017-04-01

    Several gas samples have been collected from natural gas manifestations at the island of Kos. Most of them are found underwater along the southern coast of the island. On land two anomalous degassing areas have been recognized. These are characterised by lack of vegetation and after long dry periods by the presence of sulfate salts efflorescences. Almost all the gases are CO2-dominated (CO2 ranging from 88 to 99%) with minor amounts of N2 (up to 7%) and CH4 (up to 2.6%). Only the on-land manifestations have also significant contents of H2 (up to 0.2%) and H2S (up to 0.3%). Only one underwater manifestation is N2-dominated (61-99%) with CH4 (0.6-11%) and low CO2 (0.1-26%). The isotopic composition of He shows values ranging from 0.84 to 6.72 R/RA indicating a sometimes strong mantle contribution with the highest values measured in two of the most strongly degassing areas (Paradise Beach and Volcania). C-isotopic composition of CO2 is in the range from -3.6 to 0.6 ‰ vs V-PDB with most of the values around -1‰ indicating a mixed mantle - limestones origin. Isotopic composition of CH4, ranging from -21.5 to 2.8‰ for C and from -143 to 36‰ for H, points to a geothermal origin with sometimes evident secondary oxidation processes. CO2-flux measurements showed values up to about 10,000 g/m2/day in the areas of Volcania and Kokkino Nero and up to about 50,000 g/m2/day at Paradise beach. Preliminary CO2 output estimations gave values of 8.8 and 4 tons/day for the first two areas respectively and of 2.7 tons/day for the latter. The total output of the island (15.5 tons/day) should be considered a minimum estimation because of the incomplete coverage of the area and is comparable to the other active volcanic/geothermal systems of Greece (Nisyros, Nea Kameni and Methana).

  13. Preliminary comparison of insolation measurements, forecasts, and estimates from satellite imagery

    SciTech Connect

    Riordan, C.J.

    1984-02-01

    Two national insolation data products recently initiated by the National Oceanic and Atmospheric Administration (NOAA) are examined and compared with ground measurements. The products are the National Weather Service (NWS) insolation forecasts and the National Environmental Satellite Data and Information Service (NESDIS) satellite estimates of insolation. All insolation data were converted to daily global horizontal insolation in units of kWh m/sup -2/ and divided by extraterrestrial radiation on a horizontal surface to yield atmospheric transmittance. The mean absolute difference in transmittance between ground measurements and the NOAA estimates ranged from .087 to 0.135 for the limited data set. Recommendations are: (1) to evaluate recent improvements to the NESDIS algorithm; (2) to define criteria for evaluation of the products with respect to purposes and specific applications; and (3) to perform expanded evaluations and refine algorithms if necessary.

  14. Irrigated rice area estimation using remote sensing techniques: Project's proposal and preliminary results. [Rio Grande do Sul, Brazil

    NASA Technical Reports Server (NTRS)

    Parada, N. D. J. (Principal Investigator); Deassuncao, G. V.; Moreira, M. A.; Novaes, R. A.

    1984-01-01

    The development of a methodology for annual estimates of irrigated rice crop in the State of Rio Grande do Sul, Brazil, using remote sensing techniques is proposed. The project involves interpretation, digital analysis, and sampling techniques of LANDSAT imagery. Results are discussed from a preliminary phase for identifying and evaluating irrigated rice crop areas in four counties of the State, for the crop year 1982/1983. This first phase involved just visual interpretation techniques of MSS/LANDSAT images.

  15. Performance Analysis of an Improved MUSIC DoA Estimator

    NASA Astrophysics Data System (ADS)

    Vallet, Pascal; Mestre, Xavier; Loubaton, Philippe

    2015-12-01

    This paper adresses the statistical performance of subspace DoA estimation using a sensor array, in the asymptotic regime where the number of samples and sensors both converge to infinity at the same rate. Improved subspace DoA estimators were derived (termed as G-MUSIC) in previous works, and were shown to be consistent and asymptotically Gaussian distributed in the case where the number of sources and their DoA remain fixed. In this case, which models widely spaced DoA scenarios, it is proved in the present paper that the traditional MUSIC method also provides DoA consistent estimates having the same asymptotic variances as the G-MUSIC estimates. The case of DoA that are spaced of the order of a beamwidth, which models closely spaced sources, is also considered. It is shown that G-MUSIC estimates are still able to consistently separate the sources, while it is no longer the case for the MUSIC ones. The asymptotic variances of G-MUSIC estimates are also evaluated.

  16. Preliminary Assessment of Variable Speed Power Turbine Technology on Civil Tiltrotor Size and Performance

    NASA Technical Reports Server (NTRS)

    Snyder, Christopher A.; Acree, Cecil W., Jr.

    2012-01-01

    A Large Civil Tiltrotor (LCTR) conceptual design was developed as part of the NASA Heavy Lift Rotorcraft Systems Investigation in order to establish a consistent basis for evaluating the benefits of advanced technology for large tiltrotors. The concept has since evolved into the second-generation LCTR2, designed to carry 90 passengers for 1,000 nm at 300 knots, with vertical takeoff and landing capability. This paper performs a preliminary assessment of variable-speed power turbine technology on LCTR2 sizing, while maintaining the same, advanced technology engine core. Six concepts were studied; an advanced, single-speed engine with a conventional power turbine layout (Advanced Conventional Engine, or ACE) using a multi-speed (shifting) gearbox. There were five variable-speed power turbine (VSPT) engine concepts, comprising a matrix of either three or four turbine stages, and fixed or variable guide vanes; plus a minimum weight, twostage, fixed-geometry VSPT. The ACE is the lightest engine, but requires a multi-speed (shifting) gearbox to maximize its fuel efficiency, whereas the VSPT concepts use a lighter, fixed-ratio gearbox. The NASA Design and Analysis of Rotorcraft (NDARC) design code was used to study the trades between rotor and engine efficiency and weight. Rotor performance was determined by Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics (CAMRAD II), and engine performance was estimated with the Numerical Propulsion System Simulation (NPSS). Design trades for the ACE vs. VSPT are presented in terms of vehicle gross and empty weight, propulsion system weight and mission fuel burn for the civil mission. Because of its strong effect on gearbox weight and on both rotor and engine efficiency, rotor speed was chosen as the reference design variable for comparing design trades. Major study assumptions are presented and discussed. Impressive engine power-to-weight and fuel efficiency reduced vehicle sensitivity to propulsion system choice

  17. Estimating landslide losses - preliminary results of a seven-State pilot project

    USGS Publications Warehouse

    Highland, Lynn M.

    2006-01-01

    reliable information on economic losses associated with landslides. Each State survey examined the availability, distribution, and inherent uncertainties of economic loss data in their study areas. Their results provide the basis for identifying the most fruitful methods of collecting landslide loss data nationally, using methods that are consistent and provide common goals. These results can enhance and establish the future directions of scientific investigation priorities by convincingly documenting landslide risks and consequences that are universal throughout the 50 States. This report is organized as follows: A general summary of the pilot project history, goals, and preliminary conclusions from the Lincoln, Neb. workshop are presented first. Internet links are then provided for each State report, which appear on the internet in PDF format and which have been placed at the end of this open-file report. A reference section follows the reports, and, lastly, an Appendix of categories of landslide loss and sources of loss information is included for the reader's information. Please note: The Oregon Geological Survey has also submitted a preliminary report on indirect loss estimation methodology, which is also linked with the others. Each State report is unique and presented in the form in which it was submitted, having been independently peer reviewed by each respective State survey. As such, no universal 'style' or format has been adopted as there have been no decisions on which inventory methods will be recommended to the 50 states, as of this writing. The reports are presented here as information for decision makers, and for the record; although several reports provide recommendations on inventory methods that could be adopted nationwide, currently no decisions have been made on adopting a uniform methodology for the States.

  18. Performance analysis of subspace-based parameter estimation algorithms

    NASA Astrophysics Data System (ADS)

    Vaccaro, Richard J.

    1990-06-01

    New perturbation formulas were developed for signal and orthogonal subspaces which are estimated from a noisy data matrix. These formulas are: (1) based on a finite amount of data; (2) derived under the assumption of high signal-to-noise ratio; and (3) applicable to arrays of arbitrary geometry, and they provide a common foundation for all analyses. A number of array processing algorithms were analyzed which are classified as follows: (1) Signal subspace algorithms: ESPRIT, state-space realization (including TAM), and Matrix Pencil; (2) orthogonal subspace algorithms: MUSIC and Min-Norm. Analytical variance formulas were developed for the case in which estimates are obtained by searching for the extrema of a function (used with arbitrary array geometry), as well as the case in which estimates are obtained by rooting a polynomial or finding the eigenvalues of a matrix (used with a uniform line array geometry). In addition, improvements were developed for a state-space algorithm for frequency-wavenumber (2-D) estimation. A procedure to pair individual frequency and wavenumber estimates was given, and it was also shown how a 2-D forward-backward data matrix can be used to improve the performance of the state-space approach.

  19. An Accurate Link Correlation Estimator for Improving Wireless Protocol Performance

    PubMed Central

    Zhao, Zhiwei; Xu, Xianghua; Dong, Wei; Bu, Jiajun

    2015-01-01

    Wireless link correlation has shown significant impact on the performance of various sensor network protocols. Many works have been devoted to exploiting link correlation for protocol improvements. However, the effectiveness of these designs heavily relies on the accuracy of link correlation measurement. In this paper, we investigate state-of-the-art link correlation measurement and analyze the limitations of existing works. We then propose a novel lightweight and accurate link correlation estimation (LACE) approach based on the reasoning of link correlation formation. LACE combines both long-term and short-term link behaviors for link correlation estimation. We implement LACE as a stand-alone interface in TinyOS and incorporate it into both routing and flooding protocols. Simulation and testbed results show that LACE: (1) achieves more accurate and lightweight link correlation measurements than the state-of-the-art work; and (2) greatly improves the performance of protocols exploiting link correlation. PMID:25686314

  20. Mars Science Laboratory Entry, Descent and Landing System Development Challenges and Preliminary Flight Performance

    NASA Technical Reports Server (NTRS)

    Steltzner, Adam D.; San Martin, A. Miguel; Rivellini, Tommaso P.

    2013-01-01

    The Mars Science Laboratory project recently landed the Curiosity rover on the surface of Mars. With the success of the landing system, the performance envelope of entry, descent, and landing capabilities has been extended over the previous state of the art. This paper will present an overview of the MSL entry, descent, and landing system, a discussion of a subset of its development challenges, and include a discussion of preliminary results of the flight reconstruction effort.

  1. Mars Science Laboratory Entry, Descent and Landing System Development Challenges and Preliminary Flight Performance

    NASA Technical Reports Server (NTRS)

    Steltzner, Adam D.; San Martin, A. Miguel; Rivellini, Tommaso P.

    2013-01-01

    The Mars Science Laboratory project recently landed the Curiosity rover on the surface of Mars. With the success of the landing system, the performance envelope of entry, descent, and landing capabilities has been extended over the previous state of the art. This paper will present an overview of the MSL entry, descent, and landing system, a discussion of a subset of its development challenges, and include a discussion of preliminary results of the flight reconstruction effort.

  2. Empirical tests of performance of some M - estimators

    NASA Astrophysics Data System (ADS)

    Banaś, Marek; Ligas, Marcin

    2014-12-01

    The paper presents an empirical comparison of performance of three well known M - estimators (i.e. Huber, Tukey and Hampel's M - estimators) and also some new ones. The new M - estimators were motivated by weighting functions applied in orthogonal polynomials theory, kernel density estimation as well as one derived from Wigner semicircle probability distribution. M - estimators were used to detect outlying observations in contaminated datasets. Calculations were performed using iteratively reweighted least-squares (IRLS). Since the residual variance (used in covariance matrices construction) is not a robust measure of scale the tests employed also robust measures i.e. interquartile range and normalized median absolute deviation. The methods were tested on a simple leveling network in a large number of variants showing bad and good sides of M - estimation. The new M - estimators have been equipped with theoretical tuning constants to obtain 95% efficiency with respect to the standard normal distribution. The need for data - dependent tuning constants rather than those established theoretically is also pointed out. W artykule przedstawiono empiryczne porównanie trzech dobrze znanych M - estymatorów (Huber'a, Tukey'a oraz Hampel'a) jak również kilku nowych. Nowe estymatory motywowane były funkcjami wagowymi wykorzystywanymi w teorii wielomianów ortogonalnych, estymacji jądrowej oraz jeden motywowany przez funkcję gęstości "półokręgu" Wigner'a. Każdy z estymatorów został użyty do wykrywania obserwacji odstających w skażonych zbiorach danych. Obliczenia wykonano za pomocą "reważonej" metody najmniejszych kwadratów. Ze względu na fakt, iż wariancja resztowa (używana w konstrukcji macierzy kowariancyjnych) nie jest odpornym estymatorem skali, w testach wykorzystano również odporne miary takie jak: rozstęp ćwiartkowy oraz znormalizowane odchylenie medianowe. Testy wykonano na prostej sieci niwelacyjnej w dużej ilości wariantów ukazuj

  3. Performance and Weight Estimates for an Advanced Open Rotor Engine

    NASA Technical Reports Server (NTRS)

    Hendricks, Eric S.; Tong, Michael T.

    2012-01-01

    NASA s Environmentally Responsible Aviation Project and Subsonic Fixed Wing Project are focused on developing concepts and technologies which may enable dramatic reductions to the environmental impact of future generation subsonic aircraft. The open rotor concept (also historically referred to an unducted fan or advanced turboprop) may allow for the achievement of this objective by reducing engine fuel consumption. To evaluate the potential impact of open rotor engines, cycle modeling and engine weight estimation capabilities have been developed. The initial development of the cycle modeling capabilities in the Numerical Propulsion System Simulation (NPSS) tool was presented in a previous paper. Following that initial development, further advancements have been made to the cycle modeling and weight estimation capabilities for open rotor engines and are presented in this paper. The developed modeling capabilities are used to predict the performance of an advanced open rotor concept using modern counter-rotating propeller designs. Finally, performance and weight estimates for this engine are presented and compared to results from a previous NASA study of advanced geared and direct-drive turbofans.

  4. Sensitivity of the optimal preliminary design of a transport to operational constraints and performance index

    NASA Technical Reports Server (NTRS)

    Sliwa, S. M.

    1980-01-01

    Constrained parameter optimization was used to perform the optimal preliminary design of a medium range transport configuration. The impact of choosing a performance index was studied and the required fare for a 15 percent return-on-investment was proposed as a figure-of-merit. A number of design constants and constraint functions were systematically varied to document the sensitivities of the optimal design to a variety of economic and technological assumptions. Additionally, a comparison is made for each of the parameter variations between the baseline configuration and the optimally redesigned configuration.

  5. Preliminary validation of a new methodology for estimating dose reduction protocols in neonatal chest computed radiographs

    NASA Astrophysics Data System (ADS)

    Don, Steven; Whiting, Bruce R.; Hildebolt, Charles F.; Sehnert, W. James; Ellinwood, Jacquelyn S.; Töpfer, Karin; Masoumzadeh, Parinaz; Kraus, Richard A.; Kronemer, Keith A.; Herman, Thomas; McAlister, William H.

    2006-03-01

    The risk of radiation exposure is greatest for pediatric patients and, thus, there is a great incentive to reduce the radiation dose used in diagnostic procedures for children to "as low as reasonably achievable" (ALARA). Testing of low-dose protocols presents a dilemma, as it is unethical to repeatedly expose patients to ionizing radiation in order to determine optimum protocols. To overcome this problem, we have developed a computed-radiography (CR) dose-reduction simulation tool that takes existing images and adds synthetic noise to create realistic images that correspond to images generated with lower doses. The objective of our study was to determine the extent to which simulated, low-dose images corresponded with original (non-simulated) low-dose images. To make this determination, we created pneumothoraces of known volumes in five neonate cadavers and obtained images of the neonates at 10 mR, 1 mR and 0.1 mR (as measured at the cassette plate). The 10-mR exposures were considered "relatively-noise-free" images. We used these 10 mR-images and our simulation tool to create simulated 0.1- and 1-mR images. For the simulated and original images, we identified regions of interest (ROI) of the entire chest, free-in-air region, and liver. We compared the means and standard deviations of the ROI grey-scale values of the simulated and original images with paired t tests. We also had observers rate simulated and original images for image quality and for the presence or absence of pneumothoraces. There was no statistically significant difference in grey-scale-value means nor standard deviations between simulated and original entire chest ROI regions. The observer performance suggests that an exposure >=0.2 mR is required to detect the presence or absence of pneumothoraces. These preliminary results indicate that the use of the simulation tool is promising for achieving ALARA exposures in children.

  6. Characterization and estimation of permeability correlation structure from performance data

    SciTech Connect

    Ershaghi, I.; Al-Qahtani, M.

    1997-08-01

    In this study, the influence of permeability structure and correlation length on the system effective permeability and recovery factors of 2-D cross-sectional reservoir models, under waterflood, is investigated. Reservoirs with identical statistical representation of permeability attributes are shown to exhibit different system effective permeability and production characteristics which can be expressed by a mean and variance. The mean and variance are shown to be significantly influenced by the correlation length. Detailed quantification of the influence of horizontal and vertical correlation lengths for different permeability distributions is presented. The effect of capillary pressure, P{sub c1} on the production characteristics and saturation profiles at different correlation lengths is also investigated. It is observed that neglecting P{sub c} causes considerable error at large horizontal and short vertical correlation lengths. The effect of using constant as opposed to variable relative permeability attributes is also investigated at different correlation lengths. Next we studied the influence of correlation anisotropy in 2-D reservoir models. For a reservoir under five-spot waterflood pattern, it is shown that the ratios of breakthrough times and recovery factors of the wells in each direction of correlation are greatly influenced by the degree of anisotropy. In fully developed fields, performance data can aid in the recognition of reservoir anisotropy. Finally, a procedure for estimating the spatial correlation length from performance data is presented. Both the production performance data and the system`s effective permeability are required in estimating the correlation length.

  7. Estimating Distances from Parallaxes. II. Performance of Bayesian Distance Estimators on a Gaia-like Catalogue

    NASA Astrophysics Data System (ADS)

    Astraatmadja, Tri L.; Bailer-Jones, Coryn A. L.

    2016-12-01

    Estimating a distance by inverting a parallax is only valid in the absence of noise. As most stars in the Gaia catalog will have non-negligible fractional parallax errors, we must treat distance estimation as a constrained inference problem. Here we investigate the performance of various priors for estimating distances, using a simulated Gaia catalog of one billion stars. We use three minimalist, isotropic priors, as well an anisotropic prior derived from the observability of stars in a Milky Way model. The two priors that assume a uniform distribution of stars—either in distance or in space density—give poor results: The root mean square fractional distance error, {f}{rms}, grows far in excess of 100% once the fractional parallax error, {f}{true}, is larger than 0.1. A prior assuming an exponentially decreasing space density with increasing distance performs well once its single parameter—the scale length— has been set to an appropriate value: {f}{rms} is roughly equal to {f}{true} for {f}{true}\\lt 0.4, yet does not increase further as {f}{true} increases up to to 1.0. The Milky Way prior performs well except toward the Galactic center, due to a mismatch with the (simulated) data. Such mismatches will be inevitable (and remain unknown) in real applications, and can produce large errors. We therefore suggest adopting the simpler exponentially decreasing space density prior, which is also less time-consuming to compute. Including Gaia photometry improves the distance estimation significantly for both the Milky Way and exponentially decreasing space density prior, yet doing so requires additional assumptions about the physical nature of stars.

  8. Performance assessment methodology as applied to the Greater Confinement Disposal site: Preliminary results of the third performance iteration

    SciTech Connect

    Brown, T.J.; Baer, T.A.

    1994-12-31

    The US Department of Energy has contracted Sandia National Laboratories to conduct a performance assessment of the Greater Confinement Disposal facility, Nevada. The performance assessment is an iterative process in which transport models are used to prioritize site characterization data collection. Then the data are used to refine the conceptual and performance assessment models. The results of the first two performance assessment iterations indicate that the site is likely to comply with the performance standards under the existing hydrologic conditions. The third performance iteration expands the conceptual model of the existing transport system to include possible future events and incorporates these processes in the performance assessment models. The processes included in the third performance assessment are climate change, bioturbation, plant uptake, erosion, upward advection, human intrusion and subsidence. The work completed to date incorporates the effects of bioturbation, erosion and subsidence in the performance assessment model. Preliminary analyses indicate that the development of relatively deep-rooting plant species at the site, which could occur due to climate change, irrigated farming or subsidence, poses the greatest threat to the site`s performance.

  9. A preliminary estimate of the EUVE cumulative distribution of exposure time on the unit sphere. [Extreme Ultra-Violet Explorer

    NASA Technical Reports Server (NTRS)

    Tang, C. C. H.

    1984-01-01

    A preliminary study of an all-sky coverage of the EUVE mission is given. Algorithms are provided to compute the exposure of the celestial sphere under the spinning telescopes, taking into account that during part of the exposure time the telescopes are blocked by the earth. The algorithms are used to give an estimate of exposure time at different ecliptic latitudes as a function of the angle of field of view of the telescope. Sample coverage patterns are also given for a 6-month mission.

  10. A preliminary estimate of the EUVE cumulative distribution of exposure time on the unit sphere. [Extreme Ultra-Violet Explorer

    NASA Technical Reports Server (NTRS)

    Tang, C. C. H.

    1984-01-01

    A preliminary study of an all-sky coverage of the EUVE mission is given. Algorithms are provided to compute the exposure of the celestial sphere under the spinning telescopes, taking into account that during part of the exposure time the telescopes are blocked by the earth. The algorithms are used to give an estimate of exposure time at different ecliptic latitudes as a function of the angle of field of view of the telescope. Sample coverage patterns are also given for a 6-month mission.

  11. Injury Risk Estimation Expertise: Interdisciplinary Differences in Performance on the ACL Injury Risk Estimation Quiz.

    PubMed

    Petushek, Erich J; Ward, Paul; Cokely, Edward T; Myer, Gregory D

    2015-11-01

    Simple observational assessment of movement is a potentially low-cost method for anterior cruciate ligament (ACL) injury screening and prevention. Although many individuals utilize some form of observational assessment of movement, there are currently no substantial data on group skill differences in observational screening of ACL injury risk. The purpose of this study was to compare various groups' abilities to visually assess ACL injury risk as well as the associated strategies and ACL knowledge levels. The hypothesis was that sports medicine professionals would perform better than coaches and exercise science academics/students and that these subgroups would all perform better than parents and other general population members. Cross-sectional study; Level of evidence, 3. A total of 428 individuals, including physicians, physical therapists, athletic trainers, strength and conditioning coaches, exercise science researchers/students, athletes, parents, and members of the general public participated in the study. Participants completed the ACL Injury Risk Estimation Quiz (ACL-IQ) and answered questions related to assessment strategy and ACL knowledge. Strength and conditioning coaches, athletic trainers, physical therapists, and exercise science students exhibited consistently superior ACL injury risk estimation ability (+2 SD) as compared with sport coaches, parents of athletes, and members of the general public. The performance of a substantial number of individuals in the exercise sciences/sports medicines (approximately 40%) was similar to or exceeded clinical instrument-based biomechanical assessment methods (eg, ACL nomogram). Parents, sport coaches, and the general public had lower ACL-IQ, likely due to their lower ACL knowledge and to rating the importance of knee/thigh motion lower and weight and jump height higher. Substantial cross-professional/group differences in visual ACL injury risk estimation exist. The relatively profound differences in injury

  12. Performance comparison of motion estimation algorithms on digital video images

    NASA Astrophysics Data System (ADS)

    Ali, N. A.; Ja'Afar, A. S.; Anathakrishnan, K. S.

    2009-12-01

    This paper presents a comparative study on technique to achieve high compression ratio in video coding. The focus is on the Block Matching Motion Estimation (BMME) techniques. It has been particularly used in various coding standards. In the BMME, search patterns and the center-biased characteristics of motion vector (MV) have large impact on the search speed and quality of video. Three fast Block Matching Algorithms (BMAs) of motion estimation through block matching have been implemented and performance of these three has been tested using MATLAB software. The Cross Diamond Search (CDS) is compared with Full Search (FS) and Cross Search (CS) algorithms based on search points (search speed) and peak signal-to-noise ratio (PSNR) as the quality of the video. The CDS algorithm was designed to fit the cross-center-biased (CCB) MV distribution characteristics of the real-world video sequences. CDS compares favorably with the other algorithms for low motion sequences in terms of speed, quality and computational complexity. Keywords: Block-matching, motion estimation, digital video compression, cross-centered biased, cross diamond search.

  13. Performance comparison of motion estimation algorithms on digital video images

    NASA Astrophysics Data System (ADS)

    Ali, N. A.; Ja'afar, A. S.; Anathakrishnan, K. S.

    2010-03-01

    This paper presents a comparative study on technique to achieve high compression ratio in video coding. The focus is on the Block Matching Motion Estimation (BMME) techniques. It has been particularly used in various coding standards. In the BMME, search patterns and the center-biased characteristics of motion vector (MV) have large impact on the search speed and quality of video. Three fast Block Matching Algorithms (BMAs) of motion estimation through block matching have been implemented and performance of these three has been tested using MATLAB software. The Cross Diamond Search (CDS) is compared with Full Search (FS) and Cross Search (CS) algorithms based on search points (search speed) and peak signal-to-noise ratio (PSNR) as the quality of the video. The CDS algorithm was designed to fit the cross-center-biased (CCB) MV distribution characteristics of the real-world video sequences. CDS compares favorably with the other algorithms for low motion sequences in terms of speed, quality and computational complexity. Keywords: Block-matching, motion estimation, digital video compression, cross-centered biased, cross diamond search.

  14. How to perform meaningful estimates of genetic effects.

    PubMed

    Alvarez-Castro, José M; Le Rouzic, Arnaud; Carlborg, Orjan

    2008-05-02

    Although the genotype-phenotype map plays a central role both in Quantitative and Evolutionary Genetics, the formalization of a completely general and satisfactory model of genetic effects, particularly accounting for epistasis, remains a theoretical challenge. Here, we use a two-locus genetic system in simulated populations with epistasis to show the convenience of using a recently developed model, NOIA, to perform estimates of genetic effects and the decomposition of the genetic variance that are orthogonal even under deviations from the Hardy-Weinberg proportions. We develop the theory for how to use this model in interval mapping of quantitative trait loci using Halley-Knott regressions, and we analyze a real data set to illustrate the advantage of using this approach in practice. In this example, we show that departures from the Hardy-Weinberg proportions that are expected by sampling alone substantially alter the orthogonal estimates of genetic effects when other statistical models, like F2 or G2A, are used instead of NOIA. Finally, for the first time from real data, we provide estimates of functional genetic effects as sets of effects of natural allele substitutions in a particular genotype, which enriches the debate on the interpretation of genetic effects as implemented both in functional and in statistical models. We also discuss further implementations leading to a completely general genotype-phenotype map.

  15. Performance estimation for threat detection in CT systems

    NASA Astrophysics Data System (ADS)

    Montgomery, Trent; Karl, W. Clem; Castañón, David A.

    2017-05-01

    Detecting the presence of hazardous materials in suitcases and carry-on luggage is an important problem in aviation security. As the set of threats is expanding, there is a corresponding need to increase the capabilities of explosive detection systems to address these threats. However, there is a lack of principled tools for predicting the performance of alternative designs for detection systems. In this paper, we describe an approach for computing bounds on the achievable classification performance of material discrimination systems based on empirical statistics that estimate the f-divergence of the underlying features. Our approach can be used to examine alternative physical observation modalities and measurement configurations, as well as variations in reconstruction and feature extraction algorithms.

  16. Preliminary estimates of spatially distributed net infiltration and recharge for the Death Valley region, Nevada-California

    USGS Publications Warehouse

    Hevesi, J.A.; Flint, A.L.; Flint, L.E.

    2002-01-01

    A three-dimensional ground-water flow model has been developed to evaluate the Death Valley regional flow system, which includes ground water beneath the Nevada Test Site. Estimates of spatially distributed net infiltration and recharge are needed to define upper boundary conditions. This study presents a preliminary application of a conceptual and numerical model of net infiltration. The model was developed in studies at Yucca Mountain, Nevada, which is located in the approximate center of the Death Valley ground-water flow system. The conceptual model describes the effects of precipitation, runoff, evapotranspiration, and redistribution of water in the shallow unsaturated zone on predicted rates of net infiltration; precipitation and soil depth are the two most significant variables. The conceptual model was tested using a preliminary numerical model based on energy- and water-balance calculations. Daily precipitation for 1980 through 1995, averaging 202 millimeters per year over the 39,556 square kilometers area of the ground-water flow model, was input to the numerical model to simulate net infiltration ranging from zero for a soil thickness greater than 6 meters to over 350 millimeters per year for thin soils at high elevations in the Spring Mountains overlying permeable bedrock. Estimated average net infiltration over the entire ground-water flow model domain is 7.8 millimeters per year.To evaluate the application of the net-infiltration model developed on a local scale at Yucca Mountain, to net-infiltration estimates representing the magnitude and distribution of recharge on a regional scale, the net-infiltration results were compared with recharge estimates obtained using empirical methods. Comparison of model results with previous estimates of basinwide recharge suggests that the net-infiltration estimates obtained using this model may overestimate recharge because of uncertainty in modeled precipitation, bedrock permeability, and soil properties for

  17. Preliminary estimates of spatially distributed net infiltration and recharge for the Death Valley region, Nevada-California

    SciTech Connect

    Hevesi, J.A.; Flint, A.L.; Flint, L.E.

    2002-07-18

    A three-dimensional ground-water flow model has been developed to evaluate the Death Valley regional flow system, which includes ground water beneath the Nevada Test Site. Estimates of spatially distributed net infiltration and recharge are needed to define upper boundary conditions. This study presents a preliminary application of a conceptual and numerical model of net infiltration. The model was developed in studies at Yucca Mountain, Nevada, which is located in the approximate center of the Death Valley ground-water flow system. The conceptual model describes the effects of precipitation, runoff, evapotranspiration, and redistribution of water in the shallow unsaturated zone on predicted rates of net infiltration; precipitation and soil depth are the two most significant variables. The conceptual model was tested using a preliminary numerical model based on energy- and water-balance calculations. Daily precipitation for 1980 through 1995, averaging 202 millimeters per year over the 39,556 square kilometers area of the ground-water flow model, was input to the numerical model to simulate net infiltration ranging from zero for a soil thickness greater than 6 meters to over 350 millimeters per year for thin soils at high elevations in the Spring Mountains overlying permeable bedrock. Estimated average net infiltration over the entire ground-water flow model domain is 7.8 millimeters per year. To evaluate the application of the net-infiltration model developed on a local scale at Yucca Mountain, to net-infiltration estimates representing the magnitude and distribution of recharge on a regional scale, the net-infiltration results were compared with recharge estimates obtained using empirical methods. Comparison of model results with previous estimates of basinwide recharge suggests that the net-infiltration estimates obtained using this model may overestimate recharge because of uncertainty in modeled precipitation, bedrock permeability, and soil properties for

  18. Developing a library of display effects on pilot performance: Methods, meta-analyses, and performance estimates

    NASA Astrophysics Data System (ADS)

    Salud, Ellen

    The design of NextGen and current-day cockpit displays are critical for efficient pilot performance and situation awareness on the flight deck. Before deployment of a design into the cockpit the costs and benefits that a display design imposes on performance and situation awareness should be considered. In this thesis, a design tool was developed to support the design of NextGen displays for situation awareness and performance. This design tool is a library of pilot performance estimates. Through literature reviews and meta-analyses of empirical data, the library was developed to provide display designers 1) qualitative distinctions of display properties that either support or limit full situation awareness, and 2) quantitative performance time estimates until situation awareness as a function of various display formats. A systematic method was also developed for future augmentation of the library.

  19. PDM performance Test Results and Preliminary Analysis: Incompressible and Compressible Fluids

    SciTech Connect

    Dreesen, D.S.; Gruenhagan, E.; Cohen, J.C.; Moran, D.W.

    1999-02-01

    Three, small diameter, Moineau, positive displacement (drilling) motors (PDMs) were dynamometer tested using water, air-water mist, air-water foam, and aerated water. The motors included (1) a 1.5-inch OD, single-lobe mud motor; (2) a 1.69-inch OD, 5:6 multi-lobe mud motor; and (3) a 1.75-inch OD, 5:6 multi-lobe air motor. This paper describes the test apparatus, procedures, data analysis, and results. Incompressible and compressible fluid performance are compared; linear performance, predicted by a positive displacement motor model, is identified where it occurs. Preliminary results and conclusions are (1) the performance of all three motors is accurately modeled using a two-variable, linear model for incompressible fluid and (2) the model was not successfully adapted to model compressible fluid performance.

  20. The indicator performance estimate approach to determining acceptable wilderness conditions

    NASA Astrophysics Data System (ADS)

    Hollenhorst, Steven; Gardner, Lisa

    1994-11-01

    Using data from a study conducted in the Cranberry Wilderness Area of West Virginia, United States, this paper describes how a modified importance—performance approach can be used to prioritize wilderness indicators and determine how much change from the pristine is acceptable. The approach uses two key types of information: (1) indicator importance, or visitor opinion as to which wilderness indicators have the greatest influence on their experience, and (2) management performance, or the extent to which actual indicator conditions exceed or are within visitor expectations. Performance was represented by calculating indicator performance estimates (IPEs), as defined by standardized differences between actual conditions and visitor preferences for each indicator. The results for each indicator are then presented graphically on a four-quadrant matrix for objective interpretation. Each quadrant represents a management response: keep up the good work, concentrate here, low priority, or possible overkill. The technique allows managers to more systematically and effectively utilize information routinely collected during the limits of acceptable change wilderness planning process.

  1. Early Estimates of SEER Cancer Incidence for 2012: Approaches, Opportunities, and Cautions for Obtaining Preliminary Estimates of Cancer Incidence

    PubMed Central

    Lewis, Denise Riedel; Chen, Huann-Sheng; Midthune, Douglas N.; Cronin, Kathleen A.; Krapcho, Martin F.; Feuer, Eric J.

    2015-01-01

    BACKGROUND The National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program collects and publishes population-based cancer incidence data from registries covering approximately 28% (seer.cancer.gov/registries/data.html) of the US population. SEER incidence rates are released annually in April from data submitted the prior November. The time needed to identify, consolidate, clean, and submit data requires the latest diagnosis year included to be 3 years before release. Approaches, opportunities, and cautions for an earlier release of data based on a February submission are described. METHODS First, cases submitted in February for the latest diagnosis year represented 92% to 98% of those in the following November submission. A reporting delay model was used to statistically adjust counts in recent diagnosis years for cases projected in the future. February submissions required larger adjustment factors than November submissions. Second, trends were checked to assess the validity. RESULTS Most cancer sites had similar annual percent change (APC) trends for February and November 2013. Male colon and rectum cancer and female lung and bronchus cancer showed an acceleration in declining APC trends only in February. Average annual percent change (AAPC) trends for the 2 submissions were similar for all sites. CONCLUSIONS For the first time, preliminary 2012 incidence rates, based on February submissions, are provided. An accelerated decline starting in 2008 for male colon and rectum cancer rates and male lung cancer rates did not persist when 2012 data were added. An earlier release of SEER data is possible. Caution must be exercised when one is interpreting changing trends. Use of the more conservative AAPC is advised. PMID:25739953

  2. Microseismic Network Performance Estimation: Comparing Predictions to an Earthquake Catalogue

    NASA Astrophysics Data System (ADS)

    Greig, Wesley; Ackerley, Nick

    2014-05-01

    -time estimates of a dynamic noise field are available then it is possible to obtain near real-time, dynamic measures of network performance.

  3. Wind estimates from cloud motions - Preliminary results from phases I, II and III of an in situ aircraft verification experiment

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Shenk, W. E.; Skillman, W. C.

    1976-01-01

    The accuracy of wind estimates derived from cloud motion is under investigation. Aircraft measurements of the ambient wind field have been compared with simultaneous inertial navigation system descriptions of the extent and motion of 40 tropical cumulus and 5 cirrus clouds. Preliminary results indicate that cloud-motion wind estimates are sufficiently accurate to be used in sensitive divergence, vorticity, and vertical motion calculations. The magnitude of the vector difference between the cirrus cloud velocity and the mean wind of the cloud layer was found to be about 1.6 m/sec. The major source of error is thought to be in determination of the position of the cloud. In the case of cumulus clouds, the magnitude of the vector difference between the aircraft-measured cloud motion and the cloud-base wind is less than 1.3 m/sec.

  4. Performance of ultrasound fetal weight estimation in twins.

    PubMed

    Dimassi, Kaouther; Karoui, Abir; Triki, Amel; Gara, Mohamed Faouzi

    2016-03-01

    Ultrasonography is an essential tool in the management of twin pregnancies. Fetal weight estimation is useful to anticipate neonatal care in case of weight restriction or growth discordance. To assess the accuracy of estimated fetal weight (EFW) in twins and to assess the accuracy of sonographic examination to predict birth weight discordance (BWD) and small birth weight (SBW).    Methods : This was  a longitudinal prospective study over a period of one year. We have included 50 twin pregnancies with a first trimester ultrasound calculated term and specified chorionicity. An ultrasound EFW was scheduled for all patients within an interval of 4 days before delivery. We calculated the differences between EFW and BW in terms of absolute difference and percentage error. We studied the correlation and the agreement between EFW and BW. Finally we calculated the sensitivity, the specificity, PPV and NPV of ultrasound in the diagnosis of BWD and SBW. Absolute differences between BWF and BW were similar for the two twins. The relative difference was 7.7% [0-32] for T1 and 8.2% [0-27] for T2. The margin of error was greater than 10% in 38% of the cases for T1 and in 34% of cases for T2. Furthermore, correlation coefficients R1 and R2 for T1 and T2 were close to 1; R 1 =0.87 and  R 2 = 0.89. Linear regression analysis allowed us to calculate the birth weight based on the estimated weight and this according to the following equations: For the first twin BW T1 = 0.846 * EFW 415,57+ T1 For the second twin BW T2 = 65.68 + 0.963 * EFW T2 in 34% of cases for T2. Chorionicity, presentation and gestational age did not affect the estimations. Ultrasonography in the diagnosis of SBW had a sensitivity of 90.32%, a specificity of 76.82%, a (PPV) of 80% and a (VPN) of 87%. The performance of ultrasound in the diagnosis of BWD varied according to the adopted threshold. Ultrasound is an effective examination to estimate twins weight. Regarding prenatal diagnosis of birth weight

  5. A Control Variate Method for Probabilistic Performance Assessment. Improved Estimates for Mean Performance Quantities of Interest

    SciTech Connect

    MacKinnon, Robert J.; Kuhlman, Kristopher L

    2016-05-01

    We present a method of control variates for calculating improved estimates for mean performance quantities of interest, E(PQI) , computed from Monte Carlo probabilistic simulations. An example of a PQI is the concentration of a contaminant at a particular location in a problem domain computed from simulations of transport in porous media. To simplify the presentation, the method is described in the setting of a one- dimensional elliptical model problem involving a single uncertain parameter represented by a probability distribution. The approach can be easily implemented for more complex problems involving multiple uncertain parameters and in particular for application to probabilistic performance assessment of deep geologic nuclear waste repository systems. Numerical results indicate the method can produce estimates of E(PQI)having superior accuracy on coarser meshes and reduce the required number of simulations needed to achieve an acceptable estimate.

  6. Preliminary Results on the Evaluation of a Fleet Post-Training Performance Evaluation Technique.

    ERIC Educational Resources Information Center

    Rafacz, Bernard A.; Foley, Paul P.

    A study was conducted by the Navy to develop and evaluate human performance reliability estimates for electronic maintenance. Data were collected using the Personnel Identification Information Forms, the Technical Proficiency Checkout Form, and the Job Performance Questionnaire. On the basis of the total number of uncommonly effective and the…

  7. On a stochastic approach to a code performance estimation

    SciTech Connect

    Gorshenin, Andrey K.; Frenkel, Sergey L.

    2016-06-08

    The main goal of an efficient profiling of software is to minimize the runtime overhead under certain constraints and requirements. The traces built by a profiler during the work, affect the performance of the system itself. One of important aspect of an overhead arises from the randomness of variability in the context in which the application is embedded, e.g., due to possible cache misses, etc. Such uncertainty needs to be taken into account in the design phase. In order to overcome these difficulties we propose to investigate this issue through the analysis of the probability distribution of the difference between profiler’s times for the same code. The approximating model is based on the finite normal mixtures within the framework of the method of moving separation of mixtures. We demonstrate some results for the MATLAB profiler using plotting of 3D surfaces by the function surf. The idea can be used for an estimating of a program efficiency.

  8. Alcohol and student performance: estimating the effect of legal access.

    PubMed

    Lindo, Jason M; Swensen, Isaac D; Waddell, Glen R

    2013-01-01

    We consider the effect of legal access to alcohol on student achievement. Our preferred approach identifies the effect through changes in one's performance after gaining legal access to alcohol, controlling flexibly for the expected evolution of grades as one makes progress towards their degree. We also report RD-based estimates but argue that an RD design is not well suited to the research question in our setting. We find that students' grades fall below their expected levels upon being able to drink legally, but by less than previously documented. We also show that there are effects on women and that the effects are persistent. Using the 1997 National Longitudinal Survey of Youth, we show that students drink more often after legal access but do not consume more drinks on days on which they drink. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. On a stochastic approach to a code performance estimation

    NASA Astrophysics Data System (ADS)

    Gorshenin, Andrey K.; Frenkel, Sergey L.; Korolev, Victor Yu.

    2016-06-01

    The main goal of an efficient profiling of software is to minimize the runtime overhead under certain constraints and requirements. The traces built by a profiler during the work, affect the performance of the system itself. One of important aspect of an overhead arises from the randomness of variability in the context in which the application is embedded, e.g., due to possible cache misses, etc. Such uncertainty needs to be taken into account in the design phase. In order to overcome these difficulties we propose to investigate this issue through the analysis of the probability distribution of the difference between profiler's times for the same code. The approximating model is based on the finite normal mixtures within the framework of the method of moving separation of mixtures. We demonstrate some results for the MATLAB profiler using plotting of 3D surfaces by the function surf. The idea can be used for an estimating of a program efficiency.

  10. FASTSim: A Model to Estimate Vehicle Efficiency, Cost and Performance

    SciTech Connect

    Brooker, A.; Gonder, J.; Wang, L.; Wood, E.; Lopp, S.; Ramroth, L.

    2015-05-04

    The Future Automotive Systems Technology Simulator (FASTSim) is a high-level advanced vehicle powertrain systems analysis tool supported by the U.S. Department of Energy’s Vehicle Technologies Office. FASTSim provides a quick and simple approach to compare powertrains and estimate the impact of technology improvements on light- and heavy-duty vehicle efficiency, performance, cost, and battery batches of real-world drive cycles. FASTSim’s calculation framework and balance among detail, accuracy, and speed enable it to simulate thousands of driven miles in minutes. The key components and vehicle outputs have been validated by comparing the model outputs to test data for many different vehicles to provide confidence in the results. A graphical user interface makes FASTSim easy and efficient to use. FASTSim is freely available for download from the National Renewable Energy Laboratory’s website (see www.nrel.gov/fastsim).

  11. Estimation on the First Cycle of the Annual Forest Inventory System: Methods, Preliminary Results, and Observations

    Treesearch

    Mark H. Hansen; Gary J. Brand; Daniel G. Wendt; Ronald E. McRoberts

    2001-01-01

    The first year of annual FIA data collection in the North Central region was completed for 1999 in Indiana, Iowa, Minnesota, and Missouri. Estimates of timberland area, total growing-stock volume and growing-stock volume per acre are presented. These estimates are based on data from 1 year, collected at the base Federal inventory intensity, a lower intensity sample...

  12. Preliminary evaluation of spectral, normal and meteorological crop stage estimation approaches

    NASA Technical Reports Server (NTRS)

    Cate, R. B.; Artley, J. A.; Doraiswamy, P. C.; Hodges, T.; Kinsler, M. C.; Phinney, D. E.; Sestak, M. L. (Principal Investigator)

    1980-01-01

    Several of the projects in the AgRISTARS program require crop phenology information, including classification, acreage and yield estimation, and detection of episodal events. This study evaluates several crop calendar estimation techniques for their potential use in the program. The techniques, although generic in approach, were developed and tested on spring wheat data collected in 1978. There are three basic approaches to crop stage estimation: historical averages for an area (normal crop calendars), agrometeorological modeling of known crop-weather relationships agrometeorological (agromet) crop calendars, and interpretation of spectral signatures (spectral crop calendars). In all, 10 combinations of planting and biostage estimation models were evaluated. Dates of stage occurrence are estimated with biases between -4 and +4 days while root mean square errors range from 10 to 15 days. Results are inconclusive as to the superiority of any of the models and further evaluation of the models with the 1979 data set is recommended.

  13. Scaling multiconjugate adaptive optics performance estimates to extremely large telescopes

    NASA Astrophysics Data System (ADS)

    Ellerbroek, Brent L.; Rigaut, Francois J.

    2000-07-01

    Multi-conjugate adaptive optics (MCAO) is a key technology for extremely large, ground-based telescopes (ELT's) because it enables near-uniform atmospheric turbulence compensation over fields-of-view considerably larger than can be corrected with more conventional AO systems. Quantitative performance evaluation using detailed analytical or simulation models is difficult, however, due to the very large number of deformable mirror (DM) actuators, wave front sensors (WFS) subapertures, and guide stars which might comprise an MCAO system for an ELT. This paper employs more restricted minimal variance estimation methods to evaluate the fundamental performance limits imposed by anisoplanatism alone upon MCAO performance for a range of sample cases. Each case is defined by a atmospheric turbulence profile, telescope aperture diameter, field-of-view, guide star constellation, and set of DM conjugate ranges. For a Kolmogorov turbulence spectrum with an infinite outer scale, MCAO performance for a whole range of aperture diameters and proportional fields-of-view can be computed at once using a scaling law analogous to the (D/dO)5/3 formula for the cone effect. For 30 meter telescopes, useful levels of performance are possible across a 1.0 - 2.0 arc minute square field-of-view using 5 laser guide stars (LGS's) and 3 DM's, and somewhat larger fields can be corrected using 9 guide stars and 4 mirrors. 3 or more tip/tilt natural guide stars (NGS's) are necessary to detect modes of tilt anisoplanatism which cannot be detected using LGS's, however. LGS MCAO performance is a quite weak function of aperture diameter for a fixed field-of-view, and it is tempting to scale these results to larger apertures. NGS MCAO performance is moderately superior to LGS MCAO if the NGS constellation is within the compensated field-of-view, but degrades rapidly as the guide stars move away from the field. The penalty relaxes slowly with increasing aperture diameter, but how to extrapolate this trend

  14. Subject-specific estimation of central aortic blood pressure via system identification: preliminary in-human experimental study.

    PubMed

    Fazeli, Nima; Kim, Chang-Sei; Rashedi, Mohammad; Chappell, Alyssa; Wang, Shaohua; MacArthur, Roderick; McMurtry, M Sean; Finegan, Barry; Hahn, Jin-Oh

    2014-10-01

    This paper demonstrates preliminary in-human validity of a novel subject-specific approach to estimation of central aortic blood pressure (CABP) from peripheral circulatory waveforms. In this "Individualized Transfer Function" (ITF) approach, CABP is estimated in two steps. First, the circulatory dynamics of the cardiovascular system are determined via model-based system identification, in which an arterial tree model is characterized based on the circulatory waveform signals measured at the body's extremity locations. Second, CABP waveform is estimated by de-convolving peripheral circulatory waveforms from the arterial tree model. The validity of the ITF approach was demonstrated using experimental data collected from 13 cardiac surgery patients. Compared with the invasive peripheral blood pressure (BP) measurements, the ITF approach yielded significant reduction in errors associated with the estimation of CABP, including 1.9-2.6 mmHg (34-42 %) reduction in BP waveform errors (p < 0.05) as well as 5.8-9.1 mmHg (67-76 %) and 6.0-9.7 mmHg (78-85 %) reductions in systolic and pulse pressure (SP and PP) errors (p < 0.05). It also showed modest but significant improvement over the generalized transfer function approach, including 0.1 mmHg (2.6 %) reduction in BP waveform errors as well as 0.7 (20 %) and 5.0 mmHg (75 %) reductions in SP and PP errors (p < 0.05).

  15. Effects of a yoga lifestyle intervention on performance-related characteristics of musicians: a preliminary study.

    PubMed

    Khalsa, Sat Bir S; Cope, Stephen

    2006-08-01

    Previous research has suggested that yoga and meditation practices are effective in stress management, alleviating anxiety and musculoskeletal problems and improving mood and cognitive and physical performance. Musicians experience a number of challenges in their profession including high levels of stress, performance anxiety and performance-related musculoskeletal conditions. Yoga and meditation techniques are therefore potentially useful practices for professional musicians. Musicians enrolled in a prestigious 2-month summer fellowship program were invited to participate in a regular yoga and meditation program at a yoga center during the course of the program. The 10 participants in the yoga program completed baseline and end-program questionnaires evaluating performance-related musculoskeletal conditions, performance anxiety, mood and flow experience. Fellows not participating in the yoga program were recruited to serve as controls and completed the same assessments (N=8). The yoga participants showed some improvements relative to control subjects on most measures, with the relative improvement in performance anxiety being the greatest. The results from this preliminary study suggest that yoga and meditation may be beneficial as a routine practice to reduce performance anxiety in musicians.

  16. Alcohol elimination and simulator performance of male and female aviators: a preliminary report.

    PubMed

    Taylor, J L; Dolhert, N; Friedman, L; Mumenthaler, M; Yesavage, J A

    1996-05-01

    In this preliminary study of alcohol effects on aviators' flight simulator performance, we addressed some methodological issues regarding possible gender-related differences in response to alcohol. Subjects were 11 male and 12 female general aviation pilots, ages 21-40. Subjects received 8 h of training before they were tested with alcohol. On the alcohol test day they were tested before drinking, while intoxicated (target BAC of 0.08%), and 8 h after drinking. The average, observed peak BAC readings for men and women were within 0.003% of each other. We observed faster disappearance rates for women such that women reached the FAA cutoff of 0.04% approximately 1 h before men, on average. Compared to predrink performance, there was a significant decrement in simulator performance during acute intoxication, but not 8 h after drinking. There were no significant gender differences in performance before or after drinking alcohol. Slower rates of alcohol elimination were associated with larger performance changes 8 h after drinking. This is the first report to our knowledge suggesting a possible relation between alcohol elimination rate and change in performance after drinking alcohol. A 12.5% dose reduction for women appears to be adequate for achieving comparable peak BAC's for male and female groups. Future studies using measures of circadian rhythmicity in conjunction with pharmacokinetic and performance measures could potentially shed light on differences in subjects' acute and delayed responses to alcohol.

  17. Dose estimates for the solid waste performance assessment

    SciTech Connect

    Rittman, P.D.

    1994-08-30

    The Solid Waste Performance Assessment calculations by PNL in 1990 were redone to incorporate changes in methods and parameters since then. The ten scenarios found in their report were reduced to three, the Post-Drilling Resident, the Post-Excavation Resident, and an All Pathways Irrigator. In addition, estimates of population dose to people along the Columbia River are also included. The attached report describes the methods and parameters used in the calculations, and derives dose factors for each scenario. In addition, waste concentrations, ground water concentrations, and river water concentrations needed to reach the performance objectives of 100 mrem/yr and 500 person-rem/yr are computed. Internal dose factors from DOE-0071 were applied when computing internal dose. External dose rate factors came from the GENII Version 1.485 software package. Dose calculations were carried out on a spreadsheet. The calculations are described in detail in the report for 63 nuclides, including 5 not presently in the GENII libraries. The spreadsheet calculations were checked by comparison with GENII, as described in Appendix D.

  18. Performance Estimation for Two-Dimensional Brownian Rotary Ratchet Systems

    NASA Astrophysics Data System (ADS)

    Tutu, Hiroki; Horita, Takehiko; Ouchi, Katsuya

    2015-04-01

    Within the context of the Brownian ratchet model, a molecular rotary system that can perform unidirectional rotations induced by linearly polarized ac fields and produce positive work under loads was studied. The model is based on the Langevin equation for a particle in a two-dimensional (2D) three-tooth ratchet potential of threefold symmetry. The performance of the system is characterized by the coercive torque, i.e., the strength of the load competing with the torque induced by the ac driving field, and the energy efficiency in force conversion from the driving field to the torque. We propose a master equation for coarse-grained states, which takes into account the boundary motion between states, and develop a kinetic description to estimate the mean angular momentum (MAM) and powers relevant to the energy balance equation. The framework of analysis incorporates several 2D characteristics and is applicable to a wide class of models of smooth 2D ratchet potential. We confirm that the obtained expressions for MAM, power, and efficiency of the model can enable us to predict qualitative behaviors. We also discuss the usefulness of the torque/power relationship for experimental analyses, and propose a characteristic for 2D ratchet systems.

  19. Preliminary estimates of annual agricultural pesticide use for counties of the conterminous United States, 2013

    USGS Publications Warehouse

    Baker, Nancy T.

    2015-10-05

    Thelin, G.P., and Stone, W.W., 2013, Estimation of annual agricultural pesticide use for counties of the conterminous United States, 1992–2009: U.S. Geological Survey Scientific Investigations Report 2013–5009, 54 p.

  20. A preliminary evaluation of an F100 engine parameter estimation process using flight data

    NASA Technical Reports Server (NTRS)

    Maine, Trindel A.; Gilyard, Glenn B.; Lambert, Heather H.

    1990-01-01

    The parameter estimation algorithm developed for the F100 engine is described. The algorithm is a two-step process. The first step consists of a Kalman filter estimation of five deterioration parameters, which model the off-nominal behavior of the engine during flight. The second step is based on a simplified steady-state model of the compact engine model (CEM). In this step, the control vector in the CEM is augmented by the deterioration parameters estimated in the first step. The results of an evaluation made using flight data from the F-15 aircraft are presented, indicating that the algorithm can provide reasonable estimates of engine variables for an advanced propulsion control law development.

  1. Estimating breast tomosynthesis performance in detection tasks with variable-background phantoms

    NASA Astrophysics Data System (ADS)

    Young, Stefano; Park, Subok; Anderson, S. Kyle; Badano, Aldo; Myers, Kyle J.; Bakic, Predrag

    2009-02-01

    Digital breast tomosynthesis (DBT) shows potential for improving breast cancer detection. However, this technique has not yet been fully characterized with consideration of the various uncertainties in the imaging chain and optimized with respect to system acquisition parameters. To obtain maximum diagnostic information in DBT, system optimization needs to be performed across a range of patients and acquisition parameters to quantify their impact on tumor detection performance. In addition, a balance must be achieved between x-ray dose and image quality to minimize risk to the patient while maximizing the system's detection performance. To date, researchers have applied a task-based approach to the optimization of DBT with use of mathematical observers for tasks in the signal-known-exactly background-known-exactly (SKE/BKE) and signal-known-exactly background-known statistically (SKE/BKS) paradigms1-3. However, previous observer models provided insufficient treatment of the spatial correlations between multi-angle DBT projections, so we incorporated this correlation information into the modeling methodology. We developed a computational approach that includes three-dimensional variable background phantoms for incorporating background variability, accurate ray-tracing and Poisson distributions for generating noise-free and noisy projections of the phantoms, and a channelized-Hotelling observer4 (CHO) for estimating performance in DBT. We demonstrated our method for a DBT acquisition geometry and calculated the performance of the CHO with Laguerre-Gauss channels as a function of the angular span of the system. Preliminary results indicate that the implementation of a CHO model that incorporates correlations between multi-angle projections gives different performance predictions than a CHO model that ignores multi-angle correlations. With improvement of the observer design, we anticipate more accurate investigations into the impact of multi-angle correlations and

  2. The LPSP instrument on OSO 8. II - In-flight performance and preliminary results

    NASA Technical Reports Server (NTRS)

    Bonnet, R. M.; Lemaire, P.; Vial, J. C.; Artzner, G.; Gouttebroze, P.; Jouchoux, A.; Vidal-Madjar, A.; Leibacher, J. W.; Skumanich, A.

    1978-01-01

    The paper describes the in-flight performance for the first 18 months of operation of the LPSP (Laboratoire de Physique Stellaire et Planetaire) instrument incorporated in the OSO 8 launched June 1975. By means of the instrument, an absolute pointing accuracy of nearly one second was achieved in orbit during real-time operations. The instrument uses a Cassegrain telescope and a spectrometer simultaneously observing six wavelengths. In-flight performance is discussed with attention to angular resolution, spectral resolution, dispersion and grating mechanism (spectral scanner) stability, scattered light background and dark current, photometric standardization, and absolute calibration. Real-time operation and problems are considered with reference to pointing system problems, target acquisition, and L-alpha modulation. Preliminary results involving the observational program, quiet sun and chromospheric studies, quiet chromospheric oscillation and transients, sunspots and active regions, prominences, and aeronomy investigations are reported.

  3. Visual Assessment on Coastal Cruise Tourism: A Preliminary Planning Using Importance Performance Analysis

    NASA Astrophysics Data System (ADS)

    Trisutomo, S.

    2017-07-01

    Importance-Performance Analysis (IPA) has been widely applied in many cases. In this research, IPA was applied to measure perceive on coastal tourism objects and its possibility to be developed as coastal cruise tourism in Makassar. Three objects, i.e. Akkarena recreational site, Losari public space at waterfront, and Paotere traditional Phinisi ships port, were selected and assessed visually from water area by a group of purposive resource persons. The importance and performance of 10 attributes of each site were scored using Likert scale from 1 to 5. Data were processed by SPSS-21 than resulted Cartesian graph which the scores were divided in four quadrants: Quadrant I concentric here, Quadrant II keep up the good work, Quadrant III low priority, and Quadrant IV possible overkill. The attributes in each quadrant could be considered as the platform for preliminary planning of coastal cruise tour in Makassar

  4. A Preliminary Performance Assessment for Salt Disposal of High-Level Nuclear Waste - 12173

    SciTech Connect

    Lee, Joon H.; Clayton, Daniel; Jove-Colon, Carlos; Wang, Yifeng

    2012-07-01

    A salt repository is one of the four geologic media currently under study by the U.S. DOE Office of Nuclear Energy to support the development of a long-term strategy for geologic disposal of commercial used nuclear fuel (UNF) and high-level radioactive waste (HLW). The immediate goal of the generic salt repository study is to develop the necessary modeling tools to evaluate and improve the understanding of the repository system response and processes relevant to long-term disposal of UNF and HLW in a salt formation. The current phase of this study considers representative geologic settings and features adopted from previous studies for salt repository sites. For the reference scenario, the brine flow rates in the repository and underlying interbeds are very low, and transport of radionuclides in the transport pathways is dominated by diffusion and greatly retarded by sorption on the interbed filling materials. I-129 is the dominant annual dose contributor at the hypothetical accessible environment, but the calculated mean annual dose is negligibly small. For the human intrusion (or disturbed) scenario, the mean mass release rate and mean annual dose histories are very different from those for the reference scenario. Actinides including Pu-239, Pu-242 and Np-237 are major annual dose contributors, and the calculated peak mean annual dose is acceptably low. A performance assessment model for a generic salt repository has been developed incorporating, where applicable, representative geologic settings and features adopted from literature data for salt repository sites. The conceptual model and scenario for radionuclide release and transport from a salt repository were developed utilizing literature data. The salt GDS model was developed in a probabilistic analysis framework. The preliminary performance analysis for demonstration of model capability is for an isothermal condition at the ambient temperature for the near field. The capability demonstration emphasizes key

  5. Adaptive arrival cost update for improving Moving Horizon Estimation performance.

    PubMed

    Sánchez, G; Murillo, M; Giovanini, L

    2017-03-01

    Moving horizon estimation is an efficient technique to estimate states and parameters of constrained dynamical systems. It relies on the solution of a finite horizon optimization problem to compute the estimates, providing a natural framework to handle bounds and constraints on estimates, noises and parameters. However, the approximation of the arrival cost and its updating mechanism are an active research topic. The arrival cost is very important because it provides a mean to incorporate information from previous measurements to the current estimates and it is difficult to estimate its true value. In this work, we exploit the features of adaptive estimation methods to update the parameters of the arrival cost. We show that, having a better approximation of the arrival cost, the size of the optimization problem can be significantly reduced guaranteeing the stability and convergence of the estimates. These properties are illustrated through simulation studies.

  6. Performance of Random Effects Model Estimators under Complex Sampling Designs

    ERIC Educational Resources Information Center

    Jia, Yue; Stokes, Lynne; Harris, Ian; Wang, Yan

    2011-01-01

    In this article, we consider estimation of parameters of random effects models from samples collected via complex multistage designs. Incorporation of sampling weights is one way to reduce estimation bias due to unequal probabilities of selection. Several weighting methods have been proposed in the literature for estimating the parameters of…

  7. Performance of Random Effects Model Estimators under Complex Sampling Designs

    ERIC Educational Resources Information Center

    Jia, Yue; Stokes, Lynne; Harris, Ian; Wang, Yan

    2011-01-01

    In this article, we consider estimation of parameters of random effects models from samples collected via complex multistage designs. Incorporation of sampling weights is one way to reduce estimation bias due to unequal probabilities of selection. Several weighting methods have been proposed in the literature for estimating the parameters of…

  8. Preliminary calibration of GPS signals and its effects on soil moisture estimation

    NASA Astrophysics Data System (ADS)

    Wan, Wei; Li, Huang; Chen, Xiuwan; Luo, Peng; Wan, Jiahuan

    2013-04-01

    In recent years, Global Navigation Satellite Systems Reflectometry (GNSS-R) is developed to estimate soil moisture content (SMC) as a new remote sensing tool. Signal error of Global Positioning System (GPS) bistatic radar is an important factor that affects the accuracy of SMC estimation. In this paper, two methods of GPS signal calibration involving both the direct and reflected signals are introduced, and a detailed explanation of the theoretical basis for such methods is given. An improved SMC estimation model utilizing calibrated GPS L-band signals is proposed, and the estimation accuracy is validated using the airborne GPS data from the Soil Moisture Experiment in 2002 (SMEX02). We choose 21 sites with soybean and corn in the Walnut Creek region of the US for validation. The sites are divided into three categories according to their vegetation cover: bare soil, mid-vegetation cover (Mid-Veg), and high-vegetation cover (High-Veg). The accuracy of SMC estimation is 11.17% for bare soil and 8.12% for Mid-Veg sites, much better than that of the traditional model. For High-Veg sites, the effect of signal attenuation due to vegetation cover is preliminarily taken into consideration and a linear model related to Normalized Difference Vegetation Indices (NDVI) is adopted to obtain a factor for rectifying the "over-calibration", and the error for High-Veg sites is finally reduced to 3.81%.

  9. Using ionospheric scintillation indices to estimate GPS receiver tracking performance

    NASA Astrophysics Data System (ADS)

    Elmas, Zeynep G.; Aquino, Marcio; Dodson, Alan

    2010-05-01

    The Institute of Engineering Surveying and Space Geodesy (IESSG), at the University of Nottingham, has been involved with ionospheric scintillation research and its impact on users of Global Navigation Satellite Systems (GNSS) since 2001. The IESSG hosts a comprehensive archive of scintillation data recorded during the last high of the solar cycle (2001-2003) by four GSV4004 receivers (GPS Silicon Valley) in the UK and Norway, at geographic latitudes varying from 53N to 71N. The scintillation data that forms this ~3-year archive is given solely by the widely used scintillation indices S4 and σφ (in particular the latter's 60 second version). Aquino et al (2007) describe a strategy devised to enable the combination of these scintillation indices and the spectral parameters T (the spectral strength of the phase noise at 1 Hz) and p (the spectral slope), extracted from high-rate GPS phase and amplitude data, with state-of-the-art receiver tracking models in order to study receiver tracking performance under scintillation conditions. Strangeways (2009) later devised a method to calculate the scintillation parameters T and p over a range of Fresnel frequencies based only on the scintillation indices, i.e. when high rate data is not available, as in the case of the IESSG archive of 2001-2003. This paper shows initial investigations on the retrieval of the spectral parameters p and T from actual GPS scintillation indices recorded more recently in Trondheim (app. Lat 64N, Long 10E) on 23 April 2008. T and p values are estimated from S4 and σφ and compared with actual spectral parameters obtained from high rate data that are now being recorded. The paper then takes investigations a step further, by comparing the output of a state of the art tracking model when the estimated and actual spectral parameters are used as input, respectively. This paper gives an initial insight on the applicability of the method to mitigate the effects of the ionospheric scintillation on

  10. Five-Kilometers Time Trial: Preliminary Validation of a Short Test for Cycling Performance Evaluation

    PubMed Central

    Dantas, Jose Luiz; Pereira, Gleber; Nakamura, Fabio Yuzo

    2015-01-01

    Background: The five-kilometer time trial (TT5km) has been used to assess aerobic endurance performance without further investigation of its validity. Objectives: This study aimed to perform a preliminary validation of the TT5km to rank well-trained cyclists based on aerobic endurance fitness and assess changes of the aerobic endurance performance. Materials and Methods: After the incremental test, 20 cyclists (age = 31.3 ± 7.9 years; body mass index = 22.7 ± 1.5 kg/m2; maximal aerobic power = 360.5 ± 49.5 W) performed the TT5km twice, collecting performance (time to complete, absolute and relative power output, average speed) and physiological responses (heart rate and electromyography activity). The validation criteria were pacing strategy, absolute and relative reliability, validity, and sensitivity. Sensitivity index was obtained from the ratio between the smallest worthwhile change and typical error. Results: The TT5km showed high absolute (coefficient of variation < 3%) and relative (intraclass coefficient correlation > 0.95) reliability of performance variables, whereas it presented low reliability of physiological responses. The TT5km performance variables were highly correlated with the aerobic endurance indices obtained from incremental test (r > 0.70). These variables showed adequate sensitivity index (> 1). Conclusions: TT5km is a valid test to rank the aerobic endurance fitness of well-trained cyclists and to differentiate changes on aerobic endurance performance. Coaches can detect performance changes through either absolute (± 17.7 W) or relative power output (± 0.3 W.kg-1), the time to complete the test (± 13.4 s) and the average speed (± 1.0 km.h-1). Furthermore, TT5km performance can also be used to rank the athletes according to their aerobic endurance fitness. PMID:26448846

  11. Five-Kilometers Time Trial: Preliminary Validation of a Short Test for Cycling Performance Evaluation.

    PubMed

    Dantas, Jose Luiz; Pereira, Gleber; Nakamura, Fabio Yuzo

    2015-09-01

    The five-kilometer time trial (TT5km) has been used to assess aerobic endurance performance without further investigation of its validity. This study aimed to perform a preliminary validation of the TT5km to rank well-trained cyclists based on aerobic endurance fitness and assess changes of the aerobic endurance performance. After the incremental test, 20 cyclists (age = 31.3 ± 7.9 years; body mass index = 22.7 ± 1.5 kg/m(2); maximal aerobic power = 360.5 ± 49.5 W) performed the TT5km twice, collecting performance (time to complete, absolute and relative power output, average speed) and physiological responses (heart rate and electromyography activity). The validation criteria were pacing strategy, absolute and relative reliability, validity, and sensitivity. Sensitivity index was obtained from the ratio between the smallest worthwhile change and typical error. The TT5km showed high absolute (coefficient of variation < 3%) and relative (intraclass coefficient correlation > 0.95) reliability of performance variables, whereas it presented low reliability of physiological responses. The TT5km performance variables were highly correlated with the aerobic endurance indices obtained from incremental test (r > 0.70). These variables showed adequate sensitivity index (> 1). TT5km is a valid test to rank the aerobic endurance fitness of well-trained cyclists and to differentiate changes on aerobic endurance performance. Coaches can detect performance changes through either absolute (± 17.7 W) or relative power output (± 0.3 W.kg(-1)), the time to complete the test (± 13.4 s) and the average speed (± 1.0 km.h(-1)). Furthermore, TT5km performance can also be used to rank the athletes according to their aerobic endurance fitness.

  12. Preliminary estimate of the manufacturing cost for lithium/metal sulfide cells for stationary and mobile applications

    SciTech Connect

    Chilenskas, A. A.; Schaefer, J. C.; Towle, W. L.; Barney, D. L.

    1980-01-01

    A preliminary estimate has been made of the manufacturing cost for lithium/iron sulfide cells for stationary energy-storage and electric-vehicle applications. This preliminary cost analysis indicated that the manufacturing cost (in 1979 dollars) is $24 to 41/kW-h for stationary energy-storage cells and $31 to 55/kW-h for electric-vehicle cells. The materials cost was found to contribute between 52 and 65% of this manufacturing cost. The most expensive materials and components were lithium (metal and compounds), $4.61 to $14.26/kW-h; BN felt, $4.00 to 8.50/kW-h; feed-through components, $2.40/kW-h; positive current collectors, $1.48 to 2.20/kW-h; and aluminum, $1.43 to 1.66/kW-h. The projected lithium requirements were determined for use in lithium/iron sulfide batteries and conventional uses to the year 2006. The results showed that the lithium requirements were about 275,000 short tons by 2006, which is equivalent to about 51% of presently known US resources. Of this amount, about 33% would be used in battery production and 67% consumed in conventional uses. It is expected that the lithium used in battery production would be recycled.

  13. Regression model estimation of early season crop proportions: North Dakota, some preliminary results

    NASA Technical Reports Server (NTRS)

    Lin, K. K. (Principal Investigator)

    1982-01-01

    To estimate crop proportions early in the season, an approach is proposed based on: use of a regression-based prediction equation to obtain an a priori estimate for specific major crop groups; modification of this estimate using current-year LANDSAT and weather data; and a breakdown of the major crop groups into specific crops by regression models. Results from the development and evaluation of appropriate regression models for the first portion of the proposed approach are presented. The results show that the model predicts 1980 crop proportions very well at both county and crop reporting district levels. In terms of planted acreage, the model underpredicted 9.1 percent of the 1980 published data on planted acreage at the county level. It predicted almost exactly the 1980 published data on planted acreage at the crop reporting district level and overpredicted the planted acreage by just 0.92 percent.

  14. Preliminary performance assessment for the Waste Isolation Pilot Plant, December 1992. Volume 3, Model parameters: Sandia WIPP Project

    SciTech Connect

    Not Available

    1992-12-29

    This volume documents model parameters chosen as of July 1992 that were used by the Performance Assessment Department of Sandia National Laboratories in its 1992 preliminary performance assessment of the Waste Isolation Pilot Plant (WIPP). Ranges and distributions for about 300 modeling parameters in the current secondary data base are presented in tables for the geologic and engineered barriers, global materials (e.g., fluid properties), and agents that act upon the WIPP disposal system such as climate variability and human-intrusion boreholes. The 49 parameters sampled in the 1992 Preliminary Performance Assessment are given special emphasis with tables and graphics that provide insight and sources of data for each parameter.

  15. Preliminary Results of Performance Measurements on a Cylindrical Hall-Effect Thruster with Magnetic Field Generated by Permanent Magnets

    NASA Technical Reports Server (NTRS)

    Polzin, K. A.; Raitses, Y.; Merino, E.; Fisch, N. J.

    2008-01-01

    The performance of a low-power cylindrical Hall thruster, which more readily lends itself to miniaturization and low-power operation than a conventional (annular) Hall thruster, was measured using a planar plasma probe and a thrust stand. The field in the cylindrical thruster was produced using permanent magnets, promising a power reduction over previous cylindrical thruster iterations that employed electromagnets to generate the required magnetic field topology. Two sets of ring-shaped permanent magnets are used, and two different field configurations can be produced by reorienting the poles of one magnet relative to the other. A plasma probe measuring ion flux in the plume is used to estimate the current utilization for the two magnetic configurations. The measurements indicate that electron transport is impeded much more effectively in one configuration, implying a higher thrust efficiency. Preliminary thruster performance measurements on this configuration were obtained over a power range of 100-250 W. The thrust levels over this power range were 3.5-6.5 mN, with anode efficiencies and specific impulses spanning 14-19% and 875- 1425 s, respectively. The magnetic field in the thruster was lower for the thrust measurements than the plasma probe measurements due to heating and weakening of the permanent magnets, reducing the maximum field strength from 2 kG to roughly 750-800 G. The discharge current levels observed during thrust stand testing were anomalously high compared to those levels measured in previous experiments with this thruster.

  16. Performance Estimation of Silicon-Based Self-Cooling Device

    NASA Astrophysics Data System (ADS)

    Fukuda, Shinji; Sabi, Yuichi; Kawahara, Toshio; Yamaguchi, Satarou

    2013-05-01

    Since self-cooling devices were first proposed, several materials have been tested for their suitability to be used in them. A self-cooling device requires a high Seebeck coefficient, a low electrical resistivity, and a high thermal conductivity. Here, we report experimental results for single-crystal silicon doped with boron. Samples were fabricated with carrier densities in the range of 2.0×1015 to 1.6×1019 cm-3, and their Seebeck coefficient and electrical resistivity were measured. Silicon with a carrier density of 1.6×1019 cm-3 has a power factor of 4.8×10-3 W/(K2.m) at room temperature. The cooling capability of a self-cooling device was estimated using a one-dimensional model. The results suggest that a self-cooling device based on silicon with a high carrier density can have a higher heat removal performance than a conventional silicon power device of the same size.

  17. Performance analysis of bullet trajectory estimation: Approach, simulation, and experiments

    SciTech Connect

    Ng, L.C.; Karr, T.J.

    1994-11-08

    This paper describes an approach to estimate a bullet`s trajectory from a time sequence of angles-only observations from a high-speed camera, and analyzes its performance. The technique is based on fitting a ballistic model of a bullet in flight along with unknown source location parameters to a time series of angular observations. The theory is developed to precisely reconstruct, from firing range geometry, the actual bullet trajectory as it appeared on the focal plane array and in real space. A metric for measuring the effective trajectory track error is also presented. Detailed Monte-Carlo simulations assuming different bullet ranges, shot-angles, camera frame rates, and angular noise show that angular track error can be as small as 100 {mu}rad for a 2 mrad/pixel sensor. It is also shown that if actual values of bullet ballistic parameters were available, the bullet s source location variables, and the angles of flight information could also be determined.

  18. A preliminary estimate of geoid-induced variations in repeat orbit satellite altimeter observations

    NASA Technical Reports Server (NTRS)

    Brenner, Anita C.; Beckley, B. D.; Koblinsky, C. J.

    1990-01-01

    Altimeter satellites are often maintained in a repeating orbit to facilitate the separation of sea-height variations from the geoid. However, atmospheric drag and solar radiation pressure cause a satellite orbit to drift. For Geosat this drift causes the ground track to vary by + or - 1 km about the nominal repeat path. This misalignment leads to an error in the estimates of sea surface height variations because of the local slope in the geoid. This error has been estimated globally for the Geosat Exact Repeat Mission using a mean sea surface constructed from Geos 3 and Seasat altimeter data. Over most of the ocean the geoid gradient is small, and the repeat-track misalignment leads to errors of only 1 to 2 cm. However, in the vicinity of trenches, continental shelves, islands, and seamounts, errors can exceed 20 cm. The estimated error is compared with direct estimates from Geosat altimetry, and a strong correlation is found in the vicinity of the Tonga and Aleutian trenches. This correlation increases as the orbit error is reduced because of the increased signal-to-noise ratio.

  19. Preliminary estimation of tagamite cooling conditions (Puchezh-Katunki Astrobleme, Russia)

    NASA Technical Reports Server (NTRS)

    Sazonova, L.; Feldman, V.; Korotaeva, N.

    1993-01-01

    The velocities and initial temperatures of crystallization from super-heated shocked melts have been estimated as a result of the investigation of the structures and mineral association in impact melt rocks of Puchezh-Katunki astrobleme. The dependence of these parameters vs. the body thickness of impact melt rocks have been found.

  20. Preliminary estimate of 1942 lumber production in the Carolinas, Virginia, West Virgina, Kentucky, and Tennessee

    Treesearch

    Ardie D. Toler

    1943-01-01

    This report, giving the estimated 1942 lumber production in six states of the Appalachian Forest Experiment Station's territory, is based on a complete canvass of all sawmills. It was made during the first half of 1943 by the U.S. Forest Service in cooperation wit the Bureau of the Census, the Lumber and Lumber products Branch of the War Production Board, and the...

  1. Preliminary verification of instantaneous air temperature estimation for clear sky conditions based on SEBAL

    NASA Astrophysics Data System (ADS)

    Zhu, Shanyou; Zhou, Chuxuan; Zhang, Guixin; Zhang, Hailong; Hua, Junwei

    2017-02-01

    Spatially distributed near surface air temperature at the height of 2 m is an important input parameter for the land surface models. It is of great significance in both theoretical research and practical applications to retrieve instantaneous air temperature data from remote sensing observations. An approach based on Surface Energy Balance Algorithm for Land (SEBAL) to retrieve air temperature under clear sky conditions is presented. Taking the meteorological measurement data at one station as the reference and remotely sensed data as the model input, the research estimates the air temperature by using an iterative computation. The method was applied to the area of Jiangsu province for nine scenes by using MODIS data products, as well as part of Fujian province, China based on four scenes of Landsat 8 imagery. Comparing the air temperature estimated from the proposed method with that of the meteorological station measurement, results show that the root mean square error is 1.7 and 2.6 °C at 1000 and 30 m spatial resolution respectively. Sensitivity analysis of influencing factors reveals that land surface temperature is the most sensitive to the estimation precision. Research results indicate that the method has great potentiality to be used to estimate instantaneous air temperature distribution under clear sky conditions.

  2. Some preliminary estimates of energy utilization in even-aged northern hardwoods

    Treesearch

    William B. Leak

    1970-01-01

    Estimates of energy utilization from various sources indicate that even-aged northern hardwood stands utilize less than 1/2 percent of net solar radiation for wood, leaf, and seed production, and only about 1/10 percent for production of merchantable wood. Forest managers should seek to understand and manipulate the remaining 99+ percent of solar energy, for improving...

  3. The higher mode of surface wave derived from ambient noise and preliminary application to estimating subsurface

    NASA Astrophysics Data System (ADS)

    Zhentao, Y.; Xiaofei, C.; Jiannan, W.

    2016-12-01

    The fundamental mode is the primary component of surface wave derived from ambient noise. It is the basis of the method of structure imaging from ambient noise (e.g. SPAC, Aki 1957; F-K, Lascoss 1968; MUSIC, Schmidt 1986). It is well known, however, that if the higher modes of surface wave can be identified from data and are incorporated in the inversion of dispersion curves, the uncertainty in inversion results will be greatly reduced (e.g., Tokimastu,1997). Actually, the ambient noise indeed contains the higher modes as well in its raw data of ambient noise. If we could extract the higher modes from ambient noise, the structure inversion method of ambient noise would be greatly improved. In the past decade, there are many studies to improve SPAC and analyses the relationship of fundamental mode and higher mode (Ohri et al 2002; Asten et al. 2006; Tashiaki Ykoi 2010 ;Tatsunori Ikeda 2012). In this study, we will present a new method of identifying higher modes from ambient noise data by reprocessing the "surface waves' phases" derived from the ambient noise through cross-correlation analysis, and show preliminary application in structure inversion.

  4. Estimation of coronary risk factors in British schoolchildren: a preliminary report.

    PubMed Central

    Armstrong, N; Balding, J; Gentle, P; Kirby, B

    1990-01-01

    Surveys from several countries have identified the presence of risk factors known to be associated with coronary heart disease in children. Data on the distribution of coronary risk factor variables in British children are scarce. This study was therefore designed to test the feasibility of collecting coronary risk factor data from British children and to conduct a preliminary examination of the problem. One hundred and seven children (mean age 12.8 yr) had their height, weight, triceps skinfold and blood pressure checked. Blood samples for cholesterol and HDL-cholesterol analysis were obtained from 93 children. Peak VO2 was determined on 48 children, 76 children had their daily activity monitored and 59 children's stage of sexual maturity was assessed. The boys' peak VO2 was significantly higher than the girls, whether expressed in l.min-1 (p less than 0.05) or ml.kg.-1min-1 (p less than 0.01). No other significant differences (p greater than 0.05) between the sexes were detected. The results indicate that children have relatively high serum cholesterol levels (boys 4.58 +/- 0.79; girls 4.72 +/- 0.80 mmol.l-1). The willingness and enthusiasm of the children, parents and schools to take part in the study clearly demonstrated the feasibility of a large scale study being successfully pursued in the United Kingdom. Images Figure 1 PMID:2350671

  5. Preliminary analysis of performance and loads data from the 2-megawatt mod-1 wind turbine generator

    NASA Technical Reports Server (NTRS)

    Spera, D. A.; Viterna, L. A.; Richards, T. R.; Neustadter, H. E.

    1979-01-01

    Preliminary test data on output power versus wind speed, rotor blade loads, system dynamic behavior, and start-stop characteristics on the Mod-1 wind turbine generator are presented. These data were analyzed statistically and are compared with design predictions of system performance and loads. To date, the Mod-1 wind turbine generator has produced up to 1.5 MW of power, with a measured power versus wind speed curve which agrees closely with design. Blade loads were measured at wind speeds up to 14 m/s and also during rapid shutdowns. Peak transient loads during the most severe shutdowns are less than the design limit loads. On the inboard blade sections, fatigue loads are approximately equal to the design cyclic loads. On the outboard blade sections, however, measured cyclic loads are significantly larger than design values, but they do not appear to exceed fatigue allowable loads as yet.

  6. Preliminary Evaluation of MapReduce for High-Performance Climate Data Analysis

    NASA Technical Reports Server (NTRS)

    Duffy, Daniel Q.; Schnase, John L.; Thompson, John H.; Freeman, Shawn M.; Clune, Thomas L.

    2012-01-01

    MapReduce is an approach to high-performance analytics that may be useful to data intensive problems in climate research. It offers an analysis paradigm that uses clusters of computers and combines distributed storage of large data sets with parallel computation. We are particularly interested in the potential of MapReduce to speed up basic operations common to a wide range of analyses. In order to evaluate this potential, we are prototyping a series of canonical MapReduce operations over a test suite of observational and climate simulation datasets. Our initial focus has been on averaging operations over arbitrary spatial and temporal extents within Modern Era Retrospective- Analysis for Research and Applications (MERRA) data. Preliminary results suggest this approach can improve efficiencies within data intensive analytic workflows.

  7. Preliminary Results from Nuclear Decay Experiments Performed During the Solar Eclipse of August 1, 2008

    SciTech Connect

    Javorsek, D. II; Kerford, J. L.; Stewart, C. A.; Hoft, A. W.; Horan, T. J.; Buncher, J. B.; Fischbach, E.; Gruenwald, J. T.; Heim, J.; Kohler, M.; Longman, A.; Mattes, J. J.; Mohsinally, T.; Newport, J. R.; Jenkins, J. H.; Lee, R. H.; Morreale, B.; Morris, D. B.; O'Keefe, D.; Terry, B.

    2010-08-04

    Recent developments in efforts to determine the cause of anomalous experimental nuclear decay fluctuations suggest a possible solar influence. Here we report on the preliminary results from several nuclear decay experiments performed at Thule Air Base in Greenland during the Solar Eclipse that took place on 1 August 2008. Because of the high northern latitude and time of year, the Sun never set and thereby provided relatively stabilized conditions for nearly all environmental factors. An exhaustive list of relevant factors were monitored during the eclipse to help rule out possible systematic effects due to external influences. In addition to the normal temperature, pressure, humidity, and cloud cover associated with the outside ambient observations, we included similar measurements within the laboratory along with monitoring of the power supply output, local neutron count rates, and the Earth's local magnetic and electric fields.

  8. PORFLOW MODELING FOR A PRELIMINARY ASSESSMENT OF THE PERFORMANCE OF NEW SALTSTONE DISPOSAL UNIT DESIGNS

    SciTech Connect

    Smith, F.

    2012-08-06

    At the request of Savannah River Remediation (SRR), SRNL has analyzed the expected performance obtained from using seven 32 million gallon Saltstone Disposal Units (SDUs) in the Z-Area Saltstone Disposal Facility (SDF) to store future saltstone grout. The analysis was based on preliminary SDU final design specifications. The analysis used PORFLOW modeling to calculate the release of 20 radionuclides from an SDU and transport of the radionuclides and daughters through the vadose zone. Results from this vadose zone analysis were combined with previously calculated releases from existing saltstone vaults and FDCs and a second PORFLOW model run to calculate aquifer transport to assessment points located along a boundary 100 m from the nearest edge of the SDF sources. Peak concentrations within 12 sectors spaced along the 100 m boundary were determined over a period of evaluation extending 20,000 years after SDF closure cap placement. These peak concentrations were provided to SRR to use as input for dose calculations.

  9. Kinematic analysis of motor performance in robot-assisted surgery: a preliminary study.

    PubMed

    Nisky, Ilana; Patil, Sangram; Hsieh, Michael H; Okamura, Allison M

    2013-01-01

    The inherent dynamics of the master manipulator of a teleoperated robot-assisted surgery (RAS) system can affect the movements of a human operator, in comparison with free-space movements. To measure the effects of these dynamics on operators with differing levels of surgical expertise, a da Vinci Si system was instrumented with a custom surgeon grip fixture and magnetic pose trackers. We compared users' performance of canonical motor control movements during teleoperation with the manipulator and freehand cursor control, and found significant differences in several aspects of motion, including target acquisition error, movement speed, and acceleration. In addition, there was preliminary evidence for differences between experts and novices. These findings could impact robot design, control, and training methods for RAS.

  10. Turkish children's Bender-Gestalt Test performance: a pilot study and preliminary norms.

    PubMed

    Ozer, Serap

    2007-12-01

    The present study was undertaken to provide preliminary data for norms on the Bender-Gestalt Test for 253 children ages 5 yr., 5 mo. to 11 yr., 10 mo. in Turkey. The Koppitz Developmental Scoring System gave mean error scores of 4.2 (SD = 3.3) for girls and 3.6 (SD = 3.0) for boys. The mean error scores obtained by all age groups are presented and compared with other cross-cultural data. These scores decreased across age groups, supporting Bender's maturational hypothesis of the test. The present sample performed at a higher developmental level than the Koppitz normative sample for the 5- and 6-year age groups, while means for other age groups were similar to the original U.S. norms. That this pattern is supported in other cross-cultural studies is discussed as well as the importance of developing local norms for visual spatial tests.

  11. The performance of ravens on simple discrimination tasks: a preliminary study.

    PubMed

    Range, Friederike; Bugnyar, Thomas; Kotrschal, Kurt

    2008-04-01

    Recent studies suggest the existence of primate-like cognitive abilities in corvids. Although the learning abilities of corvids in comparison to other species have been investigated before, little is known on how corvids perform on simple discrimination tasks if tested in experimental settings comparable to those that have been used for studying complex cognitive abilities. In this study, we tested a captive group of 12 ravens (Corvus corax) on four discrimination problems and their reversals. In contrast to other studies investigating learning abilities, our ravens were not food deprived and participation in experiments was voluntary. This preliminary study showed that all ravens successfully solved feature and position discriminations and several of the ravens could solve new tasks in a few trials, making very few mistakes.

  12. The performance of ravens on simple discrimination tasks: a preliminary study

    PubMed Central

    Range, Friederike; Bugnyar, Thomas; Kotrschal, Kurt

    2015-01-01

    Recent studies suggest the existence of primate-like cognitive abilities in corvids. Although the learning abilities of corvids in comparison to other species have been investigated before, little is known on how corvids perform on simple discrimination tasks if tested in experimental settings comparable to those that have been used for studying complex cognitive abilities. In this study, we tested a captive group of 12 ravens (Corvus corax) on four discrimination problems and their reversals. In contrast to other studies investigating learning abilities, our ravens were not food deprived and participation in experiments was voluntary. This preliminary study showed that all ravens successfully solved feature and position discriminations and several of the ravens could solve new tasks in a few trials, making very few mistakes. PMID:25948877

  13. Frequency Estimator Performance for a Software-Based Beacon Receiver

    NASA Technical Reports Server (NTRS)

    Zemba, Michael J.; Morse, Jacquelynne Rose; Nessel, James A.; Miranda, Felix

    2014-01-01

    As propagation terminals have evolved, their design has trended more toward a software-based approach that facilitates convenient adjustment and customization of the receiver algorithms. One potential improvement is the implementation of a frequency estimation algorithm, through which the primary frequency component of the received signal can be estimated with a much greater resolution than with a simple peak search of the FFT spectrum. To select an estimator for usage in a QV-band beacon receiver, analysis of six frequency estimators was conducted to characterize their effectiveness as they relate to beacon receiver design.

  14. Frequency Estimator Performance for a Software-Based Beacon Receiver

    NASA Technical Reports Server (NTRS)

    Zemba, Michael J.; Morse, Jacquelynne R.; Nessel, James A.

    2014-01-01

    As propagation terminals have evolved, their design has trended more toward a software-based approach that facilitates convenient adjustment and customization of the receiver algorithms. One potential improvement is the implementation of a frequency estimation algorithm, through which the primary frequency component of the received signal can be estimated with a much greater resolution than with a simple peak search of the FFT spectrum. To select an estimator for usage in a Q/V-band beacon receiver, analysis of six frequency estimators was conducted to characterize their effectiveness as they relate to beacon receiver design.

  15. Test set readings predict clinical performance to a limited extent: preliminary findings

    NASA Astrophysics Data System (ADS)

    Soh, BaoLin P.; Lee, Warwick M.; Kench, Peter L.; Reed, Warren M.; McEntee, Mark F.; Brennan, Patrick C.

    2013-03-01

    Aim: To investigate the level of agreement between test sets and actual clinical reading Background: The performance of screen readers in detecting breast cancer is being assessed in some countries by using mammographic test sets. However, previous studies have provided little evidence that performance assessed by test sets strongly correlate to performance in clinical reading. Methods: Five clinicians from BreastScreen New South Wales participated in this study. Each clinician was asked to read 200 de-identified mammographic examinations gathered from their own case history within the BreastScreen NSW Digital Imaging Library. All test sets were designed with specific proportions of true positive, true negative, false positive and false negative examinations from the previous actual clinical reads of each reader. A prior mammogram examination for comparison (when available) was also provided for each case. Results: Preliminary analyses have shown that there is a moderate level of agreement (Kappa 0.42-0.56, p < 0.001) between laboratory test sets and actual clinical reading. In addition, a mean increase of 38% in sensitivity in the laboratory test sets as compared to their actual clinical readings was demonstrated. Specificity is similar between the laboratory test sets and actual clinical reading. Conclusion: This study demonstrated a moderate level of agreement between actual clinical reading and test set reading, which suggests that test sets have a role in reflecting clinical performance.

  16. A preliminary estimate of future communications traffic for the electric power system

    NASA Technical Reports Server (NTRS)

    Barnett, R. M.

    1981-01-01

    Diverse new generator technologies using renewable energy, and to improve operational efficiency throughout the existing electric power systems are presented. A description of a model utility and the information transfer requirements imposed by incorporation of dispersed storage and generation technologies and implementation of more extensive energy management are estimated. An example of possible traffic for an assumed system, and an approach that can be applied to other systems, control configurations, or dispersed storage and generation penetrations is provided.

  17. Altered viscoelastic properties of stroke-affected muscles estimated using ultrasound shear waves - Preliminary data.

    PubMed

    Rasool, Ghulam; Wang, Allison B; Rymer, William Z; Lee, Sabrina S M

    2016-08-01

    As a result of a brain injury such as stroke, the skeletal muscles may undergo numerous structural and functional alterations. These abnormal changes are linked to muscle weakness, joint contracture, and abnormal muscle tone and eventually, result in motor impairment. A subset of these alterations affects passive muscle stiffness, i.e., viscoelastic properties. However, in vivo estimation of changes in viscoelastic properties is a challenging task. Here, we used the shear wave velocity, estimated through ultrasound SuperSonic imaging (SSI), as a surrogate for viscoelastic properties. We estimated shear wave group and phase velocities (dispersion), and thus, quantified both elasticity and viscosity of the muscle tissue, respectively in muscles of hemiplegic stroke survivors. In these individuals, we found significantly higher group and phase velocities in the stroke-affected muscles (p<; 05) compared to those of the contralateral non-affected side. We hypothesize that in addition to changes in neural and contractile properties, there are also, changes in elastic and tissue dispersive properties through local mechanisms. An enhanced understanding of post-stroke changes in skeletal muscles will lead to better and targeted interventions for rehabilitation.

  18. Age and growth of round gobies in Lake Michigan, with preliminary mortality estimation

    USGS Publications Warehouse

    Huo, Bin; Madenjian, Charles P.; Xie, Cong X.; Zhao, Yingming; O'Brien, Timothy P.; Czesny, Sergiusz J.

    2015-01-01

    The round goby (Neogobius melanostomus) is a prevalent invasive species throughout Lake Michigan, as well as other Laurentian Great Lakes, yet little information is available on spatial variation in round goby growth within one body of water. Age and growth of round goby at three areas of Lake Michigan were studied by otolith analysis from a sample of 659 specimens collected from 2008 to 2012. Total length (TL) ranged from 48 to 131 mm for Sturgeon Bay, from 50 to 125 mm for Waukegan, and from 54 to 129 mm for Sleeping Bear Dunes. Ages ranged from 2 to 7 years for Sturgeon Bay, from 2 to 5 years for Waukegan, and from 2 to 6 years for Sleeping Bear Dunes. Area-specific and sex-specific body–otolith relationships were used to back-calculate estimates of total length at age, which were fitted to von Bertalanffy models to estimate growth rates. For both sexes, round gobies at Sleeping Bear Dunes and Waukegan grew significantly faster than those at Sturgeon Bay. However, round goby growth did not significantly differ between Sleeping Bear Dunes and Waukegan for either sex. At all three areas of Lake Michigan, males grew significantly faster than females. Based on catch curve analysis, estimates of annual mortality rates ranged from 0.79 to 0.84. These relatively high mortality rates suggested that round gobies may be under predatory control in Lake Michigan.

  19. Preliminary estimates of galactic cosmic ray shielding requirements for manned interplanetary missions

    NASA Technical Reports Server (NTRS)

    Townsend, Lawrence W.; Wilson, John W.; Nealy, John E.

    1988-01-01

    Estimates of radiation risk to the blood forming organs from galactic cosmic rays are presented for manned interplanetary missions. The calculations use the Naval Research Laboratory cosmic ray spectrum model as input into the Langley Research Center galactic cosmic ray transport code. This transport code, which transports both heavy ions and nucleons, can be used with any number of layers of target material, consisting of up to five different constituents per layer. Calculated galactic cosmic ray doses and dose equivalents behind various thicknesses of aluminum and water shielding are presented for solar maximum and solar minimum periods. Estimates of risk to the blood forming organs are made using 5 cm depth dose/dose equivalent values for water. These results indicate that at least 5 g/sq cm (5 cm) of water of 6.5 g/sq cm (2.4 cm) of aluminum shield is required to reduce annual exposure below the current recommended limit of 50 rem. Because of the large uncertainties in fragmentation parameters, and the input cosmic ray spectrum, these exposure estimates may be uncertain by as much as 70 percent. Therefore, more detailed analyses with improved inputs could indicate the need for additional shielding.

  20. Estimation of the flux tube diameters outside sunspots using Hinode observations. Preliminary results

    NASA Astrophysics Data System (ADS)

    Botygina, O. O.; Gordovskyy, M. Yu.; Lozitsky, V. G.

    2016-09-01

    Indirect estimations of diameters of the smallest flux tubes outside sunspots are made using SOT/Hinode observations of Fe I 6301.5 and 6302.5 lines. These estimations are based on the comparison of measured effective magnetic field strength B_{eff} in named lines. It is shown that B_{eff}(6301.5)/B_{eff}(6302.5)≈ 1.3 in the range B_{eff}=40-300 G, and B_{eff} (6301.5)/B_{eff}(6302.5)≈.0 for B_{eff}≤10-20 G. The first case corresponds to the two-component magnetic field with kG flux tubes and weak background field, whereas the second one corresponds to background field without flux tubes. Assuming that the field range B_{eff}=10-40 G corresponds to the case with only one flux tube in each pixel, the flux tube diameters should be 15-30 km. Possible influence of the brightness contrast and the Zeeman saturation could change this estimation by approximately 20%.

  1. Preliminary Estimates of the Potential for Carbon Mitigation in European Soils Through No-Till Farming

    DOE Data Explorer

    Smith, P. [University of Aberdeen, Aberdeen, UK; Powlson, D. [University of Aberdeen, Aberdeen, UK; Glendining, M. [University of Aberdeen, Aberdeen, UK; Smith, J. [University of Aberdeen, Aberdeen, UK

    2003-01-01

    in this paper we estimate the European potential for carbon mitigation of no-till farming using results from European tillage experiments. Our calculations suggest some potential in terms of (a) reduced agricultural fossil fuel emissions, and (b) increased soil carbon sequestration. We estimate that 100% conversion to no-till farming would be likely to sequester about 23 Tg C y–11 in the European Union or about 43 Tg C y–1 in the wider Europe (excluding the former Soviet Union). In addition, up to 3.2 Tg C y–1 could be saved in agricultural fossil fuel emissions. Compared to estimates of the potential for carbon sequestration of other carbon mitigation options, no-till agriculture shows nearly twice the potential of scenarios whereby soils are amended with organic materials. Our calculations suggest that 100% conversion to no-till agriculture in Europe could mitigate all fossil fuel-carbon emissions from agriculture in Europe. However, this is equivalent to only about 4.1% of total anthropogenic CO2-carbon produced annually in Europe (excluding the former Soviet Union) which in turn is equivalent to about 0.8% of global annual anthropogenic CO2-carbon emissions.

  2. Preliminary estimates of galactic cosmic ray shielding requirements for manned interplanetary missions

    SciTech Connect

    Townsend, L.W.; Wilson, J.W.; Nealy, J.E.

    1988-10-01

    Estimates of radiation risk to the blood forming organs from galactic cosmic rays are presented for manned interplanetary missions. The calculations use the Naval Research Laboratory cosmic ray spectrum model as input into the Langley Research Center galactic cosmic ray transport code. This transport code, which transports both heavy ions and nucleons, can be used with any number of layers of target material, consisting of up to five different constituents per layer. Calculated galactic cosmic ray doses and dose equivalents behind various thicknesses of aluminum and water shielding are presented for solar maximum and solar minimum periods. Estimates of risk to the blood forming organs are made using 5 cm depth dose/dose equivalent values for water. These results indicate that at least 5 g/sq cm (5 cm) of water of 6.5 g/sq cm (2.4 cm) of aluminum shield is required to reduce annual exposure below the current recommended limit of 50 rem. Because of the large uncertainties in fragmentation parameters, and the input cosmic ray spectrum, these exposure estimates may be uncertain by as much as 70 percent. Therefore, more detailed analyses with improved inputs could indicate the need for additional shielding.

  3. Performance validation of commercially available mobile waste-assay systems: Preliminary report

    SciTech Connect

    Schanfein, M.; Bonner, C.; Maez, R.

    1997-08-01

    Prior to disposal, nuclear waste must be accurately characterized to identify and quantify the radioactive content to reduce the radioactive hazard to the public. Validation of the waste-assay systems` performance is critical for establishing the credibility of the assay results for storage and disposal purposes. Canberra Nuclear has evaluated regulations worldwide and identified standard, modular, neutron- and gamma-waste-assay systems that can be used to characterize a large portion of existing and newly generated transuranic (TRU) and low-level waste. Before making claims or guaranteeing any system`s performance for specific waste types, the standardized systems` performance must be evaluated. Canberra and Los Alamos National Laboratory`s (LANL) Plutonium Facility developed a three-phase validation plan. During Phase One, tests were performed using simulation sources at Canberra to determine the error bounds for measurement parameters, to determine the minimum detectable activity, and to measure precision and bias. During Phase Two, two mobile systems were installed at the Plutonium Facility. LANL is providing peer review of the systems` performance for plutonium, acting as a beta test site to evaluate the waste-assay software, and providing data for {open_quotes}precertification{close_quotes} at future Department of Energy installations. (Plutonium isotopics are determined from measurements using the Multi-Group Analysis code.) Finally, the two systems` performances are evaluated for representative waste types (salt, metal, combustibles, leaded rubber, and HEPA filters). Phase Three of the validation, the Waste Isolation Pilot Plant Performance Demonstration Plan, will require approval by the National TRU Program Office. This paper describes the standard mobile waste-assay systems, the test plan, and preliminary results from the peer review outlined above in Phase Two.

  4. Performance of internal covariance estimators for cosmic shear correlation functions

    SciTech Connect

    Friedrich, O.; Seitz, S.; Eifler, T. F.; Gruen, D.

    2015-12-31

    Data re-sampling methods such as the delete-one jackknife are a common tool for estimating the covariance of large scale structure probes. In this paper we investigate the concepts of internal covariance estimation in the context of cosmic shear two-point statistics. We demonstrate how to use log-normal simulations of the convergence field and the corresponding shear field to carry out realistic tests of internal covariance estimators and find that most estimators such as jackknife or sub-sample covariance can reach a satisfactory compromise between bias and variance of the estimated covariance. In a forecast for the complete, 5-year DES survey we show that internally estimated covariance matrices can provide a large fraction of the true uncertainties on cosmological parameters in a 2D cosmic shear analysis. The volume inside contours of constant likelihood in the $\\Omega_m$-$\\sigma_8$ plane as measured with internally estimated covariance matrices is on average $\\gtrsim 85\\%$ of the volume derived from the true covariance matrix. The uncertainty on the parameter combination $\\Sigma_8 \\sim \\sigma_8 \\Omega_m^{0.5}$ derived from internally estimated covariances is $\\sim 90\\%$ of the true uncertainty.

  5. Performance of internal covariance estimators for cosmic shear correlation functions

    DOE PAGES

    Friedrich, O.; Seitz, S.; Eifler, T. F.; ...

    2015-12-31

    Data re-sampling methods such as the delete-one jackknife are a common tool for estimating the covariance of large scale structure probes. In this paper we investigate the concepts of internal covariance estimation in the context of cosmic shear two-point statistics. We demonstrate how to use log-normal simulations of the convergence field and the corresponding shear field to carry out realistic tests of internal covariance estimators and find that most estimators such as jackknife or sub-sample covariance can reach a satisfactory compromise between bias and variance of the estimated covariance. In a forecast for the complete, 5-year DES survey we show that internally estimated covariance matrices can provide a large fraction of the true uncertainties on cosmological parameters in a 2D cosmic shear analysis. The volume inside contours of constant likelihood in themore » $$\\Omega_m$$-$$\\sigma_8$$ plane as measured with internally estimated covariance matrices is on average $$\\gtrsim 85\\%$$ of the volume derived from the true covariance matrix. The uncertainty on the parameter combination $$\\Sigma_8 \\sim \\sigma_8 \\Omega_m^{0.5}$$ derived from internally estimated covariances is $$\\sim 90\\%$$ of the true uncertainty.« less

  6. Performance of sampling methods to estimate log characteristics for wildlife.

    Treesearch

    Lisa J. Bate; Torolf R. Torgersen; Michael J. Wisdom; Edward O. Garton

    2004-01-01

    Accurate estimation of the characteristics of log resources, or coarse woody debris (CWD), is critical to effective management of wildlife and other forest resources. Despite the importance of logs as wildlife habitat, methods for sampling logs have traditionally focused on silvicultural and fire applications. These applications have emphasized estimates of log volume...

  7. Dark Matter Capture and Annihilation on the First Stars: Preliminary Estimates

    SciTech Connect

    Iocco, Fabio

    2008-05-02

    Assuming that Dark Matter is dominated by WIMPs, it accretes by gravitational attraction and scattering over baryonic material and annihilates inside celestial objects, giving rise to a 'Dark Luminosity' which may potentially affect the evolution of stars. We estimate the Dark Luminosity achieved by different kinds of stars in a halo with DM properties characteristic of the ones where the first star formation episode occurs. We find that either massive, metal-free and small, galactic-like stars can achieve Dark Luminosities comparable or exceeding their nuclear ones. This might have dramatic effects over the evolution of the very first stars, known as Population III.

  8. Preliminary estimates of wind power potential at the Nevada test site

    NASA Astrophysics Data System (ADS)

    Booth, H. G.

    1981-07-01

    An assessment of the potential for the useful conversion of wind power to electrical power is given for a Nevada test site. Annual wind power availability was estimated to be sufficient. The percentage of low wind hours was found to be high, and the persistence of favorably strong winds for periods of several days at a time was low. There was a pronounced diurnal cycle in wind power availability. It is concluded that baseload electrical power requirements would require alternate energy sources. Cost effectiveness of this configuration would have to be determined.

  9. Estimation of postmortem interval using an electric impedance spectroscopy technique: a preliminary study.

    PubMed

    Mao, Shiwei; Dong, Xiuzhen; Fu, Feng; Seese, Ronald R; Wang, Zhenyuan

    2011-09-01

    The objective of this study was to develop a rapid method for the estimation of postmortem interval (PMI) using electric impedance spectroscopy. Postmortem rat spleens were studied at 10°C, 20°C, and 30°C; The results obtained demonstrated that postmortem interval negatively correlated with the absolute value of Im Z(//) (capacitive reactance component) in electrical impedance. This suggests that electric impedance spectroscopy may be a sensitive tool to determine the postmortem interval. Copyright © 2010 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

  10. A preliminary study on the association between ventilation rates in classrooms and student performance.

    PubMed

    Shaughnessy, R J; Haverinen-Shaughnessy, U; Nevalainen, A; Moschandreas, D

    2006-12-01

    Poor conditions leading to substandard indoor air quality (IAQ) in classrooms have been frequently cited in the literature over the past two decades. However, there is limited data linking poor IAQ in the classrooms to student performance. Whereas, it is assumed that poor IAQ results in reduced attendance and learning potential, and subsequent poor student performance, validating this hypothesis presents a challenge in today's school environment. This study explores the association between student performance on standardized aptitude tests that are administered to students on a yearly basis, to classroom carbon dioxide (CO2) concentrations, which provide a surrogate of ventilation being provided to each room. Data on classroom CO2 concentrations (over a 4-5 h time span within a typical school day) were recorded in fifth grade classrooms in 54 elementary schools within a school district in the USA. Results from this preliminary study yield a significant (P < 0.10) association between classroom-level ventilation rate and test results in math. They also indicate that non-linear effects may need to be considered for better representation of the association. A larger sample size is required in order to draw more definitive conclusions. Practical Implications Future studies could focus on (1) gathering more evidence on the possible association between classroom ventilation rates and students' academic performance; (2) the linear/non-linear nature of the association; and (3) whether it is possible to detect 'no observed adverse effect level' for adequate ventilation with respect to academic performance in schools. All of this information could be used to improve guidance and take regulatory actions to ensure adequate ventilation in schools. The high prevalence of low ventilation rates, combined with the growing evidence of the positive impact that sufficient ventilation has on human performance, suggests an opportunity for improving design and management of school

  11. Bounding Estimate for the 'Hot' Channel Temperature and Preliminary Calculation of Mixing in the Lower Plenum for the NGNP Point Design Using CFD

    SciTech Connect

    Richard W. Johnson; R. R. Schultz

    2004-12-01

    The power density in the core of the block next generation nuclear power plant (NGNP) will not be uniform due to geometry, core layout and fuel pin design. Recent calculations performed to optimize the core design indicate that the maximum radial variation will be 1.25 times the average. This significant radial variation in the local power density will create a variation in the temperature of the helium coolant as it cools the core. The coolant channel with the highest outlet temperature is referred to as the ‘hot’ channel. The concern is that the high temperature channels, which exit into the lower plenum as jets, called ‘hot streaking,’ will adversely affect materials in the lower plenum, the exit duct and the turbine, as well as affect the performance of the turbine. The objective of the present study is to determine or bound the maximum exit temperature of the ‘hot’ channel. The maximum hot channel temperature depends on the total coolant flow rate, which has not yet been fixed. Experiments need to be designed to capture the complex physics of the lower-plenum flow to allow assessment and validation of numerical simulations. While preliminary CFD simulations are not yet validated, they can be of use in the planning of the experiments, particularly in estimating where there are regions of high and low turbulence intensity. Mixing of the coolant is related to the turbulence intensity as well as to the overall nature of the mean flow. The purpose of the present task is to provide preliminary flow calculations of the coolant in the lower plenum to examine flow patterns and turbulence intensity.

  12. Barrier analogs: Long-term performance issues, preliminary studies, and recommendations

    SciTech Connect

    Waugh, W.J.; Chatters, J.C.; Last, G.V.; Bjornstad, B.N.; Link, S.O.; Hunter, C.R.

    1994-02-01

    The US Department of Energy`s Hanford Protective Barrier Development Program is funding studies of natural analogs of the long-term performance of waste site covers. Natural-analog studies examine past environments as evidence for projecting the future performance of engineered structures. The information generated by analog studies is needed to (1) evaluate the designs and results of short term experiments and demonstrations, (2) formulate performance-modeling problems that bound expected changes in waste site environments, and (3) understand emergent system attributes that cannot be evaluated with short-term experiments or computer models. Waste site covers will be part of dynamic environmental systems with attributes that transcend the traits of engineered components. This report discusses results of the previously unreported preliminary studies conducted in 1983 and 1984. These results indicate that analogs could play an important role in predicting the long-term behavior of engineered waste covers. Layered exposures of glacial-flood-deposited gravels mantled with silt or sand that resemble contemporary barrier designs were examined. Bergmounds, another anomaly left by cataclysmic glacial floods, were also examined as analogs of surface gravel.

  13. Preliminary Investigation of Over-all Performance of Experimental Turbojet Engine for Guided Missiles

    NASA Technical Reports Server (NTRS)

    Eustis, Robert H.; Berkey, William E.

    1947-01-01

    A preliminary investigation of the over-all performance of a simply constructed, short-life, turbojet engine was conducted. The unit was operated at a pressure altitude of 15,000 feet for ram-pressure ratios of 1.2 t o 1.8. The corrected engine speed was varied from the minimum for good combustion to about 17,000 rpm, which is approximately 75 percent of rated speed. The performance is given by generalized parameters that permit the calculation of performance at any altitude. The corrected net thrust of the turbojet engine increased with ram-pressure ratio for a given corrected engine speed above 14,500 rpm and reached a maximum of 425 pounds at a ram-pressure ratio of 1.8 and a corrected engine speed of 16,650 rpm, The corrected thrust specific fuel consumption decreased with flight speed for corrected engine speeds higher than 13,600 rpm, The minimum corrected thrust specific fuel consumption of 1.48 was obtained at a ram-pressure ratio of 1,8 and a corrected engine speed of 15,000 rpm. For all ram-pressure ratios, choking occurred in the engine for corrected engine speeds greater than 14,500 rpm.

  14. New technologies and new performances of the JCMT radio-telescope: a preliminary design study

    NASA Astrophysics Data System (ADS)

    Mian, S.; De Lorenzi, S.; Ghedin, L.; Rampini, F.; Marchiori, G.; Craig, S.

    2012-09-01

    With a diameter of 15m the James Clerk Maxwell Telescope (JCMT) is the largest astronomical telescope in the world designed specifically to operate in the submillimeter wavelength region of the spectrum. It is situated close to the summit of Mauna Kea, Hawaii, at an altitude of 4092m. Its primary reflector currently consists of a steel geodesic supporting structure and pressed aluminium panels on a passive mount. The major issues of the present reflector are its thermal stability and its panels deterioration. A preliminary design study for the replacement of the JCMT antenna dish is here presented. The requested shape error for the new reflector is <20μm RMS. The proposed solution is based on a semi-monocoque backing structure made of CFRP and on high precision electroformed panels. The choice of CFRP for the backing structure allows indeed to improve the antenna performance in terms of both stiffness and thermal stability, so that the required surface accuracy of the primary can be achieved even by adopting a passive panels system. Moreover thanks to CFRP, a considerable weight reduction of the elevation structure can be attained. The performance of the proposed solution for the JCMT antenna has been investigated through FE analyses and the assessed deformation of the structure under different loading cases has been taken into account for subsequent error budgeting. Results show that the proposed solution is in line with the requested performance. With this new backing structure, the JCMT would have the largest CFRP reflector ever built.

  15. Preliminary estimate of crustal extension during Cambrian rifting in the southern midcontinent

    SciTech Connect

    McConnell, D.A.; Gilbert, M.

    1985-01-01

    The Southern Oklahoma Aulacogen is a prominent rift extending 500+ km NW into the southern Midcontinent from the probably Cambrian plate margin. The biomodal igneous floor of the rift has been strongly structurally inverted and is now partially exposed in the core of the Wichita Mountains. Utilizing structural and stratigraphic patterns, and character of the igneous sequence, the style of tectonism and magnitude of displacement can be inferred for the initiation of the rift. Five possible extensional pulses can be related to specific igneous features although these could be part of one continuous episode lasting from about 565 to 525 mybp. Pennsylvanian transpressive faults are assumed to be reactivated Cambrian normal faults (and they may even have an earlier parentage). Using known thickness of continuous rhyolite (1.4 km), an initial width of 60 km, and a half-graben configuration, an estimate of extension is possible independent of bounding fault dip. For a brittle-ductile transition between 10 to 15 km, the brittle extension in the upper crust varies between 8-5%. Using the minimum mafic volume needed within the ductile lower crust (40,000 km/sup 3/), and a total crustal thickness of 35 to 45 km, the lower crust was extended 8-6% to 10-7%. The upper and lower crustal estimates of extension are in good agreement confirming a relatively shallow brittle-ductile transition. This is consistent with concomitant igneous activity and an enhanced geothermal gradient.

  16. Preliminary investigation of subsurface hydraulic parameter estimation using airborne electromagnetic surveys

    NASA Astrophysics Data System (ADS)

    Calvin, P. A.; Misra, D.; Metz, P. A.; Sonwalkar, V. S.; Ganguli, R.

    2009-12-01

    The characterization of subsurface hydraulic properties is critical for engineering designs in hydro-geologically and environmentally sensitive regions. Traditionally such characterization has been accomplished through drilling and well tests that measure local hydraulic and geologic properties. Due to the intrinsic variability of the subsurface hydraulics, large cross sections of samples are required to characterize a region. Such collection methods can be cost prohibitive, time inefficient, and environmentally invasive. The problematic issues related to the field collection of samples can result in a limited data set in which a large amount of interpolation and estimation is required. Airborne electromagnetic surveys (AES) offer an alternative by providing high density data coverage helping account for large spatial variability. While relationships between electrical and hydraulic properties of geologic media have been shown, methods are needed that integrate limited hydraulic data sets with geophysical surveys, such as the AES, to model the spatial variability on a large scale. In this paper the relationship between the apparent resistivity data acquired through a helicopter electromagnetic survey (HEM) and empirically determined hydraulic conductivity and its application toward large scale hydraulic modeling is explored. A geophysical data set along the Alaska Highway corridor was analyzed with respect to a subsection of hydraulic data using a supervised learning method. The computationally derived site specific relationship was then validated using the remaining hydraulic data. The results outline a method by which AES data can be used to develop a site specific relationship to model and estimate regional subsurface hydraulic parameters.

  17. Dynamic State Estimation Utilizing High Performance Computing Methods

    SciTech Connect

    Schneider, Kevin P.; Huang, Zhenyu; Yang, Bo; Hauer, Matthew L.; Nieplocha, Jaroslaw

    2009-03-18

    The state estimation tools which are currently deployed in power system control rooms are based on a quasi-steady-state assumption. As a result, the suite of operational tools that rely on state estimation results as inputs do not have dynamic information available and their accuracy is compromised. This paper presents an overview of the Kalman Filtering process and then focuses on the implementation of the predication component on multiple processors.

  18. The Greenville Fault: preliminary estimates of its long-term creep rate and seismic potential

    USGS Publications Warehouse

    Lienkaemper, James J.; Barry, Robert G.; Smith, Forrest E.; Mello, Joseph D.; McFarland, Forrest S.

    2013-01-01

    Once assumed locked, we show that the northern third of the Greenville fault (GF) creeps at 2 mm/yr, based on 47 yr of trilateration net data. This northern GF creep rate equals its 11-ka slip rate, suggesting a low strain accumulation rate. In 1980, the GF, easternmost strand of the San Andreas fault system east of San Francisco Bay, produced a Mw5.8 earthquake with a 6-km surface rupture and dextral slip growing to ≥2 cm on cracks over a few weeks. Trilateration shows a 10-cm post-1980 transient slip ending in 1984. Analysis of 2000-2012 crustal velocities on continuous global positioning system stations, allows creep rates of ~2 mm/yr on the northern GF, 0-1 mm/yr on the central GF, and ~0 mm/yr on its southern third. Modeled depth ranges of creep along the GF allow 5-25% aseismic release. Greater locking in the southern two thirds of the GF is consistent with paleoseismic evidence there for large late Holocene ruptures. Because the GF lacks large (>1 km) discontinuities likely to arrest higher (~1 m) slip ruptures, we expect full-length (54-km) ruptures to occur that include the northern creeping zone. We estimate sufficient strain accumulation on the entire GF to produce Mw6.9 earthquakes with a mean recurrence of ~575 yr. While the creeping 16-km northern part has the potential to produce a Mw6.2 event in 240 yr, it may rupture in both moderate (1980) and large events. These two-dimensional-model estimates of creep rate along the southern GF need verification with small aperture surveys.

  19. A Preliminary Study of Biomass Estimation of Boreal Forest in Alaska Using ALOS PALSAR Polarimetric Images

    NASA Astrophysics Data System (ADS)

    Li, S.; Wurtz, T.; Gens, R.

    2007-12-01

    A reliable forest biomass determination is essential for understanding and modeling ecosystem dynamics, regional and global Carbon-fluxes, and their implications in global climate and environmental changes. The full- (HH+HV+VV+VH) and 2-polarization (HH+HV) information available from the Phased Array type L-band Synthetic Aperture Radar (PALSAR) on the newly launched Japanese satellite, Advanced Land Observation Satellite (ALOS), offers a great opportunity for estimating forest biomass from Space. We investigate ALOS PALSAR application in forest biomass estimation through two approaches. The first involves SAR polarimetry. Multiple scattering within forest, especially within forest canopy causes change of vibration direction in return radar signals, resulting in increase of the proportion of cross-polarization (i.e., HV and VH) components. Consequently, the degree of polarization (the ratio of co-polarized received power-HH+VV-over the total received power) thus decreases with increasing biomass. The second approach involves with polarization phase difference (PPD) and its standard deviation. These two parameters increase with increase in multiple scattering. Therefore, they are also indicators of higher biomass. ALOS PALSAR data sets at test sites at Bonanza Creek Experimental Forest, Alaska, were acquired through the Americas ALOS Data Node (AADN) at Alaska Satellite Facility. Interferometric tools are used in data processing to relate complex images in different polarizations. The resulting interferometric phase images are used for PPD and coherence images for deviations in PPD. Analysis is made through comparison of the interferometric-based patterns of PPD and its standard deviation with ground truth gathered through previous field campaigns.

  20. Methodology for the preliminary design of high performance schools in hot and humid climates

    NASA Astrophysics Data System (ADS)

    Im, Piljae

    A methodology to develop an easy-to-use toolkit for the preliminary design of high performance schools in hot and humid climates was presented. The toolkit proposed in this research will allow decision makers without simulation knowledge easily to evaluate accurately energy efficient measures for K-5 schools, which would contribute to the accelerated dissemination of energy efficient design. For the development of the toolkit, first, a survey was performed to identify high performance measures available today being implemented in new K-5 school buildings. Then an existing case-study school building in a hot and humid climate was selected and analyzed to understand the energy use pattern in a school building and to be used in developing a calibrated simulation. Based on the information from the previous step, an as-built and calibrated simulation was then developed. To accomplish this, five calibration steps were performed to match the simulation results with the measured energy use. The five steps include: (1) Using an actual 2006 weather file with measured solar radiation, (2) Modifying lighting & equipment schedule using ASHRAE's RP-1093 methods, (3) Using actual equipment performance curves (i.e., scroll chiller), (4) Using the Winkelmann's method for the underground floor heat transfer, and (5) Modifying the HVAC and room setpoint temperature based on the measured field data. Next, the calibrated simulation of the case-study K-5 school was compared to an ASHRAE Standard 90.1-1999 code-compliant school. In the next step, the energy savings potentials from the application of several high performance measures to an equivalent ASHRAE Standard 90.1-1999 code-compliant school. The high performance measures applied included the recommendations from the ASHRAE Advanced Energy Design Guides (AEDG) for K-12 and other high performance measures from the literature review as well as a daylighting strategy and solar PV and thermal systems. The results show that the net

  1. A picture identification task as an estimate of the word-recognition performance of nonverbal adults.

    PubMed

    Wilson, R H; Antablin, J K

    1980-05-01

    The Picture Identification Task was developed to estimate the word-recognition performance of nonverbal adults. Four lists of 50 monosyllabic words each were assembled and recorded. Each test word and three rhyming alternatives were illustrated and photographed in a quadrant arrangement. The task of the patient was to point to the picture representing the recorded word that was presented through the earphone. In the first experiment with young adults, no significant differences were found between the Picture Identification Task and the Northwestern University Auditory Test No. 6 materials in an open-set response paradigm. In the second experiment, the Picture Identification Task with the picture-pointing response was compared with the Northwestern University Auditory Test No. 6 in both an open-set and a closed-set response paradigm. The results from this experiment demonstrated significant differences among the three response tasks. The easiest task was a closed-set response to words, the next was a closed-set response to pictures, and the most difficult task was an open-set response. At high stimulus-presentation levels, however, the three tasks produced similar results. Finally, the clinical use of the Picture Identification Task is described along with preliminary results obtained from 30 patients with various communicative impairments.

  2. Preliminary estimates of the quantity and quality of groundwater discharge to a section of Bear Creek in central Iowa

    SciTech Connect

    Caron, G.A.; Simpkins, W.W.; Schultz, R.C. )

    1994-04-01

    Studies in Iowa and elsewhere in the Midwest have suggested that most agrichemicals enter surface water through runoff events of tile drainage. Although it also contains agrichemicals, groundwater's contribution to surface water contamination is largely unknown, particularly in till-dominated watersheds. The purpose of this study was to estimate the quantity and quality of groundwater discharge to a 1,000-m-long section of Bear Creek in central Iowa. The study is part of a larger project that is evaluating constructed, multi-species riparian buffer strips as a Best Management Practice for agriculture. Groundwater discharge to the creek was estimated using: (1) differences in discharge between an upstream and downstream weir (minus tile drain outflow), (2) seepage meter data from the creek bed, and (3) Darcy's Law, using hydraulic gradient and K data from piezometers adjacent to the creek and minipiezometers in the creek. The authors preliminary estimates show groundwater discharge rates of 2 to 15 L/s (weirs), 10 L/s (seepage meters), and 3 L/s (Darcy's Law). Discharge in Bear Creek ranged from 100 to 400 L/s during the period; thus, groundwater contributed only a small part of the total creek discharge. Water samples from minipiezometers beneath the creek bed are characterized by NO[sub 3]-N concentrations < 3 mg/L and atrazine concentrations < 0.1 [mu]g/L. In contrast, water samples from Bear Creek typically show NO[sub 3]-N concentrations > 20 mg/L and atrazine concentrations up to 1.0 [mu]g/L. These water quality data suggest that groundwater may not be a significant contributor to agrichemical contamination of surface water in this till-dominated watershed.

  3. Preliminary estimates of economic impact of liver fluke infection in Thailand and the feasibility of irradiation as a control measure.

    PubMed

    Loaharanu, P; Sornmani, S

    1991-12-01

    Liver fluke infection by Opisthorchis viverrini is the leading cause of food-borne parasitic disease in Thailand. Approximately one third of the population in the northeastern region of the country, ie, 6-7 million, are infected by this parasite through the habit of consuming raw or insufficiently cooked freshwater fish, especially those of cyprinoid family. A recent survey showed that 60% of the work force in the Northeast between the age of 15 and 60 is infected. The estimated wage loss of this population may be approximately Baht 1,620 million (US$65 million) per annum. The estimated direct cost of medical care may be as high as Baht 495 million (US$19.4 million) per annum. Thus, the total direct cost of the infected work force is estimated to be Baht 2115 million (US$84.6 million) per annum. Irradiation of fish flesh infected by metacercaria of O. viverrini has been demonstrated as an effective method of control. A minimum dose of 0.1 kGy is effective without changing physiochemical properties of the fish flesh. This technology, therefore, shows promise as a method to control infection by O. viverrini acquired by the habit of consuming raw freshwater fish in the country. Preliminary economic analyses indicate that the public health benefit from preventing infection with this parasite could outweigh the investment cost of irradiation facilities. Detailed economic feasibility studies should be carried out to demonstrate the practical efficacy and cost-effectiveness of the treatment as a public health intervention measure in the country.

  4. Preliminary Estimate for Injury Criterion to Immediate Incapacitation by Projectile Penetration

    DTIC Science & Technology

    2012-01-01

    characterisation of the lethality of bullets and fragments against the protected human body can be performed using ballistic gelatine. A lethality...material that is calibrated to simulate human skeletal muscle but the actual target, that is, a protected human being, is composed of a variety of...actual target, i.e. a human torso, using the ComputerMan software. Based on anthropometric data, the human torso model size was changed and the depth

  5. Preliminary estimates of Gulf Stream characteristics from TOPEX data and a precise gravimetric geoid

    NASA Technical Reports Server (NTRS)

    Rapp, Richard H.; Smith, Dru A.

    1994-01-01

    TOPEX sea surface height data has been used, with a gravimetric geoid, to calculate sea surface topography across the Gulf Stream. This topography was initially computed for nine tracks on cycles 21 to 29. Due to inaccurate geoid undulations on one track, results for eight tracks are reported. The sea surface topography estimates were used to calculate parameters that describe Gulf Stream characteristics from two models of the Gulf Stream. One model was based on a Gaussian representation of the velocity while the other was a hyperbolic representation of velocity or the sea surface topography. The parameters of the Gaussian velocity model fit were a width parameter, a maximum velocity value, and the location of the maximum velocity. The parameters of the hyperbolic sea surface topography model were the width, the height jump, position, and sea surface topography at the center of the stream. Both models were used for the eight tracks and nine cycles studied. Comparisons were made between the width parameters, the maximum velocities, and the height jumps. Some of the parameter estimates were found to be highly (0.9) correlated when the hyperbolic sea surface topography fit was carried out, but such correlations were reduced for either the Gaussian velocity fits or the hyperbolic velocity model fit. A comparison of the parameters derived from 1-year TOPEX data showed good agreement with values derived by Kelly (1991) using 2.5 years of Geosat data near 38 deg N, 66 deg W longitude. Accuracy of the geoid undulations used in the calculations was of order of +/- 16 cm with the accuracy of a geoid undulation difference equal to +/- 15 cm over a 100-km line in areas with good terrestrial data coverage. This paper demonstrates that our knowledge or geoid undulations and undulation differences, in a portion of the Gulf Stream region, is sufficiently accurate to determine characteristics of the jet when used with TOPEX altimeter data. The method used here has not been shown to

  6. Examining implementation and preliminary performance indicators of veterans treatment courts: The Kentucky experience.

    PubMed

    Shannon, Lisa M; Birdwhistell, Shira; Hulbig, Shelia K; Jones, Afton Jackson; Newell, Jennifer; Payne, Connie

    2017-03-11

    Veterans' Treatment Courts (VTCs) are posited as a solution to offer rehabilitation for veterans involved in the criminal justice system. Despite the pervasive implementation of VTCs, there is little research focused specifically on VTC implementation and outcomes, which are based on other problem-solving court models such as drug court. The current study presents qualitative process evaluation data from key stakeholders (n=21) and veteran participants (n=4) to show accomplishments, challenges, and lessons learned during first-year implementation at two VTC sites. Quantitative performance data is also presented on veteran participants (n=19) served during the first year to show: types of services, monitoring, judicial interaction, sanctions/therapeutic responses, and rewards, as well as preliminary data on recidivism. Qualitative data, from both key stakeholders and veteran participants, suggests that offering rehabilitation via various program components, services/referrals, and accountability are critical to the success of the VTC. Data also provides valuable lessons learned for VTC implementation including communication, collaboration, information/protocols, and resources. Performance data shows that a variety of services are utilized and that frequent judicial interaction, drug testing, and sanctions are cornerstones of the VTC. Implications and future directions for research are discussed.

  7. Comparative evaluation of aliskiren, ramipril, and losartan on psychomotor performance in healthy volunteers: A preliminary report

    PubMed Central

    Arora, Ekta; Khajuria, Vijay; Tandon, Vishal R.; Sharma, Atul; Choudhary, Naiyma

    2014-01-01

    Aim: To compare the effects of aliskiren, ramipril, and losartan on the psychomotor performance in healthy volunteers. Materials and Methods: In this preliminary, single-dose, open-label, cross-over study conducted in 12 healthy volunteers, psychomotor assessment was carried out by four tests: Simple reaction time (SRT), multiple choice reaction time test (MCRT), critical flicker fusion frequency threshold test (CFFT), and tracking performance test (TPT). Each volunteer received a single dose of each of the three test drugs with a washout period of 10 days between different test sessions and then evaluated for post-drug scores at 2-h intervals up to 12 h and then at 24 h. The changes from the baseline scores by the test drug were statistically analyzed. Results: All the three antihypertensive drugs caused significant improvement in a similar fashion on SRT, MCRT calculated as error index, CFFT, and TPT. Aliskiren caused numerically more improvement than the other two test drugs, suggesting better cognitive profile. However, inter-drug comparisons were nonsignificant. Conclusion: The results of the study highlight improvement of the cognitive functions equally by ramipril, losartan, and aliskiren. The results of the study could be of immense clinical utility in ambulatory hypertensive patients especially engaged in sensory-motor coordination tasks like driving and operating on mechanical tools. PMID:25276630

  8. Comparative rating of consultation performance: a preliminary study and proposal for collaborative research

    PubMed Central

    Stanley, I.M.; Webster, C.A.; Webster, J.

    1985-01-01

    Factors governing the appropriateness, reliability and validity of rating scales in the measurement of professional performance are reviewed. The origin and preliminary testing among undergraduated and general practitioners of a brief consultation rating schedule is described. Statistical criteria are proposed for the analysis of ratings, by groups, in the comparison of consultation performance. Using these criteria the capacity of the 10 rating schedule items to discriminate between two contrasting consultations was examined. Each of the items was used at some time by students or doctors to express significant preference for the same consultation; and on this basis all the items are considered to merit inclusion. One item showed highly significant intra- and inter-observer reliability. The schedule is reproduced in full, together with a data-collection document and significance chart, with the aim of encouraging groups of doctors to test the validity of the items in the comparison of other pairs of consultations. It is proposed that future versions of the schedule should reflect the experience of such groups in testing existing items and in defining additional items which satisfy the proposed criteria. PMID:4020754

  9. Performance of internal covariance estimators for cosmic shear correlation functions

    NASA Astrophysics Data System (ADS)

    Friedrich, O.; Seitz, S.; Eifler, T. F.; Gruen, D.

    2016-03-01

    Data re-sampling methods such as delete-one jackknife, bootstrap or the sub-sample covariance are common tools for estimating the covariance of large-scale structure probes. We investigate different implementations of these methods in the context of cosmic shear two-point statistics. Using lognormal simulations of the convergence field and the corresponding shear field we generate mock catalogues of a known and realistic covariance. For a survey of {˜ } 5000 ° ^2 we find that jackknife, if implemented by deleting sub-volumes of galaxies, provides the most reliable covariance estimates. Bootstrap, in the common implementation of drawing sub-volumes of galaxies, strongly overestimates the statistical uncertainties. In a forecast for the complete 5-yr Dark Energy Survey, we show that internally estimated covariance matrices can provide a large fraction of the true uncertainties on cosmological parameters in a 2D cosmic shear analysis. The volume inside contours of constant likelihood in the Ωm-σ8 plane as measured with internally estimated covariance matrices is on average ≳85 per cent of the volume derived from the true covariance matrix. The uncertainty on the parameter combination Σ _8 ˜ σ _8 Ω _m^{0.5} derived from internally estimated covariances is ˜90 per cent of the true uncertainty.

  10. Nuclear war: preliminary estimates of the climatic effects of a nuclear exchange

    SciTech Connect

    MacCracken, M.C.

    1983-10-01

    The smoke rising from burning cities, industrial areas, and forests if such areas are attacked as part of a major nuclear exchange is projected to increase the hemispheric average atmospheric burden of highly absorbent carbonaceous material by 100 to 1000 times. As the smoke spreads from these fires, it would prevent sunlight from reaching the surface, leading to a sharp cooling of land areas over a several day period. Within a few weeks, the thick smoke would spread so as to largely cover the mid-latitudes of the Northern Hemisphere, cooling mid-continental smoke-covered areas by, perhaps, a few tens of degrees Celsius. Cooling of near coastal areas would be substantially less, since oceanic heat capacity would help to buffer temperature changes in such regions. The calculations on which these findings are based contain many assumptions, shortcomings and uncertainties that affect many aspects of the estimated response. It seems, nonetheless, quite possible that if a nuclear exchange involves attacks on a very large number of cities and industrial areas, thereby starting fires that generate as much smoke as is suggested by recent studies, substantial cooling could be expected that would last weeks to months over most continental regions of the Northern Hemisphere, but which may have relatively little direct effect on the Southern Hemisphere.

  11. Preliminary investigation to estimate soil NAPL retention using parametric pedotransfer functions

    NASA Astrophysics Data System (ADS)

    Hernádi, Hilda; Makó, András

    2014-10-01

    Organic liquid retention of soils is a primary input variable for modelling the nonaqueous phase liquid transport and behaviour in the subsurface. In environmental and soil physical practice, it is mainly determined by scaling based on the water retention of soils or with charts of average empirical values of organic liquid retention or the fitting parameters of hydraulic functions. Predicting the fitting parameters of organic liquid retention curves with pedotransfer functions might be a promising alternative method, but this topic has only been researched to a limited extent. Thus we investigated the applicability of different hydraulic functions (3- and 4- parameter form of the van Genuchten equation and Brutsaert equation) for fitting organic liquid retention characteristics. Multivariate linear regression was used to build and develop pedotransfer functions, modelling relations between original and transformed values of basic soil properties and organic liquid retention. We attempted to generate parametric pedotransfer functions. According to our results, the applicability of hydraulic functions for fitting nonaqueous phase liquid retention curves to the experimental data was proven. The investigations gave promising results for the possibility to estimate soil nonaqueous phase liquid retention with parametric pedotransfer functions.

  12. The interannual trend and preliminary quantitative estimation of the oceans condition in the Bohai Sea area

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Yang, Jin-kun; Miao, Qing-sheng; Gao, Xiu-min

    2017-01-01

    After different frequency observed temperature data of Bohai sea marine observation stations was analyzed, results showed that daily average sea surface temperature value obtained from 3-hour-observations (08h, 14h, 20h) which was slightly lower than that from 24-hour-observations. The general gap was within 0.10°, while the value was 0.05° for the monthly mean temperature. Daily average sea surface temperature values of 3-hour-observations have a little effect both in statistical properties and the accuracy of statistical data, which does not affect the representativeness of the data. It can be used in studying long time series problems. Analyzing the trend of the SST data changes in 1960-2012 and the SAT data changes in 1965-2012 by using the linear tendency estimate and cumulative distance square method, it can prove that SST annual variation rate was 0.010°/a, with a total increase of 0.53° in last 53 years; and SAT annual variation rate was 0.043°/a, with a total increase of 2.06° in last 48 years. Although the long-term trend of these two factors is significantly increased, but there was a significant mutation around 1987. From 1960 to 1987, it had a downward trend, after 1987 it began to grow, the upward trend has not diminished until 2009.

  13. Cross-cultural effects on IQ test performance: a review and preliminary normative indications on WAIS-III test performance.

    PubMed

    Shuttleworth-Edwards, Ann B; Kemp, Ryan D; Rust, Annegret L; Muirhead, Joanne G L; Hartman, Nigel P; Radloff, Sarah E

    2004-10-01

    This article presents a review of cross-cultural influences on Wechsler IQ tests, together with a preliminary investigation into WAIS-III test performance (English administration) for a southern African sample (age range 19-30) stratified for white English first language and black African first language, level and quality of education. ('African language' is the term used to denote the indigenous languages of black populations in southern Africa). A two-way ANOVA revealed highly significant effects for both level and quality of education within the black African first language group. Scores for the white English and black African first language groups with advantaged education were comparable with the US standardization, whereas scores for black African first language participants with disadvantaged education were significantly lower than this. Thus indications from this research are that normative studies should take account of the influential variable of quality of education, in addition to level of education. Alternatively faulty conclusions may be drawn about the effects of ethnicity, with the potential for neuropsychological misdiagnosis.

  14. Speech and Pause Characteristics in Multiple Sclerosis: A Preliminary Study of Speakers with High and Low Neuropsychological Test Performance

    ERIC Educational Resources Information Center

    Feenaughty, Lynda; Tjaden, Kris; Benedict, Ralph H. B.; Weinstock-Guttman, Bianca

    2013-01-01

    This preliminary study investigated how cognitive-linguistic status in multiple sclerosis (MS) is reflected in two speech tasks (i.e. oral reading, narrative) that differ in cognitive-linguistic demand. Twenty individuals with MS were selected to comprise High and Low performance groups based on clinical tests of executive function and information…

  15. Preliminary Review of Models, Assumptions, and Key Data used in Performance Assessments and Composite Analysis at the Idaho National Laboratory

    SciTech Connect

    Arthur S. Rood; Swen O. Magnuson

    2009-07-01

    This document is in response to a request by Ming Zhu, DOE-EM to provide a preliminary review of existing models and data used in completed or soon to be completed Performance Assessments and Composite Analyses (PA/CA) documents, to identify codes, methodologies, main assumptions, and key data sets used.

  16. Speech and Pause Characteristics in Multiple Sclerosis: A Preliminary Study of Speakers with High and Low Neuropsychological Test Performance

    ERIC Educational Resources Information Center

    Feenaughty, Lynda; Tjaden, Kris; Benedict, Ralph H. B.; Weinstock-Guttman, Bianca

    2013-01-01

    This preliminary study investigated how cognitive-linguistic status in multiple sclerosis (MS) is reflected in two speech tasks (i.e. oral reading, narrative) that differ in cognitive-linguistic demand. Twenty individuals with MS were selected to comprise High and Low performance groups based on clinical tests of executive function and information…

  17. An Evaluation of Empirical Bayes' Estimation of Value- Added Teacher Performance Measures. Working Paper #31. Revised

    ERIC Educational Resources Information Center

    Guarino, Cassandra M.; Maxfield, Michelle; Reckase, Mark D.; Thompson, Paul; Wooldridge, Jeffrey M.

    2014-01-01

    Empirical Bayes' (EB) estimation is a widely used procedure to calculate teacher value-added. It is primarily viewed as a way to make imprecise estimates more reliable. In this paper we review the theory of EB estimation and use simulated data to study its ability to properly rank teachers. We compare the performance of EB estimators with that of…

  18. Performance adaptive training control strategy for recovering wrist movements in stroke patients: a preliminary, feasibility study

    PubMed Central

    2009-01-01

    Background In the last two decades robot training in neuromotor rehabilitation was mainly focused on shoulder-elbow movements. Few devices were designed and clinically tested for training coordinated movements of the wrist, which are crucial for achieving even the basic level of motor competence that is necessary for carrying out ADLs (activities of daily life). Moreover, most systems of robot therapy use point-to-point reaching movements which tend to emphasize the pathological tendency of stroke patients to break down goal-directed movements into a number of jerky sub-movements. For this reason we designed a wrist robot with a range of motion comparable to that of normal subjects and implemented a self-adapting training protocol for tracking smoothly moving targets in order to facilitate the emergence of smoothness in the motor control patterns and maximize the recovery of the normal RoM (range of motion) of the different DoFs (degrees of Freedom). Methods The IIT-wrist robot is a 3 DoFs light exoskeleton device, with direct-drive of each DoF and a human-like range of motion for Flexion/Extension (FE), Abduction/Adduction (AA) and Pronation/Supination (PS). Subjects were asked to track a variable-frequency oscillating target using only one wrist DoF at time, in such a way to carry out a progressive splinting therapy. The RoM of each DoF was angularly scanned in a staircase-like fashion, from the "easier" to the "more difficult" angular position. An Adaptive Controller evaluated online performance parameters and modulated both the assistance and the difficulty of the task in order to facilitate smoother and more precise motor command patterns. Results Three stroke subjects volunteered to participate in a preliminary test session aimed at verify the acceptability of the device and the feasibility of the designed protocol. All of them were able to perform the required task. The wrist active RoM of motion was evaluated for each patient at the beginning and at the end

  19. Performance Analysis of Source Image Estimators in Blind Source Separation

    NASA Astrophysics Data System (ADS)

    Koldovsky, Zbynek; Nesta, Francesco

    2017-08-01

    Blind methods often separate or identify signals or signal subspaces up to an unknown scaling factor. Sometimes it is necessary to cope with the scaling ambiguity, which can be done through reconstructing signals as they are received by sensors, because scales of the sensor responses (images) have known physical interpretations. In this paper, we analyze two approaches that are widely used for computing the sensor responses, especially, in Frequency-Domain Independent Component Analysis. One approach is the least-squares projection, while the other one assumes a regular mixing matrix and computes its inverse. Both estimators are invariant to the unknown scaling. Although frequently used, their differences were not studied yet. A goal of this work is to fill this gap. The estimators are compared through a theoretical study, perturbation analysis and simulations. We point to the fact that the estimators are equivalent when the separated signal subspaces are orthogonal, and vice versa. Two applications are shown, one of which demonstrates a case where the estimators yield substantially different results.

  20. Considerations for Estimating Electrode Performance in Li-Ion Cells

    NASA Technical Reports Server (NTRS)

    Bennett, William R.

    2012-01-01

    Advanced electrode materials with increased specific capacity and voltage performance are critical to the development of Li-ion batteries with increased specific energy and energy density. Although performance metrics for individual electrodes are critically important, a fundamental understanding of the interactions of electrodes in a full cell is essential to achieving the desired performance, and for establishing meaningful goals for electrode performance. This paper presents practical design considerations for matching positive and negative electrodes in a viable design. Methods for predicting cell-level discharge voltage, based on laboratory data for individual electrodes, are presented and discussed.

  1. The design and performance estimates for the propulsion module for the booster of a TSTO vehicle

    NASA Technical Reports Server (NTRS)

    Snyder, Christopher A.; Maldonado, Jaime J.

    1991-01-01

    A NASA study of the propulsion systems for possible low-risk replacements for the Space Shuttle is presented. Results of preliminary studies to define the USAF two-stage-to-orbit (TSTO) concept to deliver 10,000 pounds to low polar orbit are described. The booster engine module consists of an over/under turbine bypass engines/ramjet engine design for acceleration from takeoff to the staging point of Mach 6.5 and approximately 100,000 feet altitude. Propulsion system performance and weight are presented with preliminary mission study results of vehicle size.

  2. Correlation estimation and performance optimization for distributed image compression

    NASA Astrophysics Data System (ADS)

    He, Zhihai; Cao, Lei; Cheng, Hui

    2006-01-01

    Correlation estimation plays a critical role in resource allocation and rate control for distributed data compression. A Wyner-Ziv encoder for distributed image compression is often considered as a lossy source encoder followed by a lossless Slepian-Wolf encoder. The source encoder consists of spatial transform, quantization, and bit plane extraction. In this work, we find that Gray code, which has been extensively used in digital modulation, is able to significantly improve the correlation between the source data and its side information. Theoretically, we analyze the behavior of Gray code within the context of distributed image compression. Using this theoretical model, we are able to efficiently allocate the bit budget and determine the code rate of the Slepian-Wolf encoder. Our experimental results demonstrate that the Gray code, coupled with accurate correlation estimation and rate control, significantly improves the picture quality, by up to 4 dB, over the existing methods for distributed image compression.

  3. Neurophysiological Estimates of Human Performance Capabilities in Aerospace Systems

    DTIC Science & Technology

    1976-11-30

    remote from the dynograph and tape recorder - hence the advantage of telemetry - and the noise from these devices do not interfere with sleep. The...thresholds occur at 7 Hz, with fields of 10 v/m (Gavalas, Walter, Hamer & Adey, 1970; Gavalas- Medici and Day-Magdaleno, 1976). In recent years, our...sensitivities noted in monkeys making subjective 𔄀ime estimates (Gavalas- Medici and Day-Magdaleno, 1976). Thresholds at 10"/ volts/cm are within an order

  4. Performance Analysis of Time-Delay Estimation Systems

    DTIC Science & Technology

    1984-08-01

    and signal ambiguities on the attainable mean square estimation errors. When the lower bound is plotted as a function of signal-to-noise ratio ( SNR ...one observes two distinct threshold phenomena dividing the SNR domain into three disjointed segments: at high SNR the lower bound coincides with the...moderate SNR (between the two thresholds), the lower bound exceeds the CRLB by a factor of 12( 0/W)2 where and0 W are, respectively, the center frequency

  5. Estimation of Launch Vehicle Performance Parameters from an Orbiting Sensor

    DTIC Science & Technology

    1981-12-01

    13 3 Geometry for azimuth derivation ............... 15 4 Initial positions of target and observer ..... 25 5 Measurement ambiguity...ga*hzring of data previously unavailable from the ground or air. Measurements of elevation and azimuth from satellite nfrared sensors fall into this...missiles. Of primary interest in this development was the ability of the filter to estimate accelerations of the target vehicle in addition to its

  6. A smartphone-based platform to test the performance of wireless mobile networks and preliminary findings

    NASA Astrophysics Data System (ADS)

    Geng, Xinli; Xu, Hao; Qin, Xiaowei

    2016-10-01

    During the last several years, the amount of wireless network traffic data increased fast and relative technologies evolved rapidly. In order to improve the performance and Quality of Experience (QoE) of wireless network services, the analysis of field network data and existing delivery mechanisms comes to be a promising research topic. In order to achieve this goal, a smartphone based platform named Monitor and Diagnosis of Mobile Applications (MDMA) was developed to collect field data. Based on this tool, the web browsing service of High Speed Downlink Packet Access (HSDPA) network was tested. The top 200 popular websites in China were selected and loaded on smartphone for thousands times automatically. Communication packets between the smartphone and the cell station were captured for various scenarios (e.g. residential area, urban roads, bus station etc.) in the selected city. A cross-layer database was constructed to support the off-line analysis. Based on the results of client-side experiments and analysis, the usability of proposed portable tool was verified. The preliminary findings and results for existing web browsing service were also presented.

  7. Preliminary results for the design, fabrication, and performance of a backside-illuminated avalanche drift detector

    NASA Astrophysics Data System (ADS)

    Qiao, Yun; Liang, Kun; Chen, Wen-Fei; Han, De-Jun

    2013-10-01

    The detection of low-level light is a key technology in various experimental scientific studies. As a photon detector, the silicon photomultiplier (SiPM) has gradually become an alternative to the photomultiplier tube (PMT) in many applications in high-energy physics, astroparticle physics, and medical imaging because of its high photon detection efficiency (PDE), good resolution for single-photon detection, insensitivity to magnetic field, low operating voltage, compactness, and low cost. However, primarily because of the geometric fill factor, the PDE of most SiPMs is not very high; in particular, for those SiPMs with a high density of micro cells, the effective area is small, and the bandwidth of the light response is narrow. As a building block of the SiPM, the concept of the backside-illuminated avalanche drift detector (ADD) was first proposed by the Max Planck Institute of Germany eight years ago; the ADD is promising to have high PDE over the full energy range of optical photons, even ultraviolet light and X-ray light, and because the avalanche multiplication region is very small, the ADD is beneficial for the fabrication of large-area SiPMs. However, because of difficulties in design and fabrication, no significant progress had been made, and the concept had not yet been verified. In this paper, preliminary results in the design, fabrication, and performance of a backside-illuminated ADD are reported; the difficulties in and limitations to the backside-illuminated ADD are analyzed.

  8. Using glint to perform geometric signature prediction and pose estimation

    NASA Astrophysics Data System (ADS)

    Paulson, Christopher; Zelnio, Edmund; Gorham, LeRoy; Wu, Dapeng

    2012-05-01

    We consider two problems in this paper. The rst problem is to construct a dictionary of elements without using synthetic data or a subset of the data collection; the second problem is to estimate the orientation of the vehicle, independent of the elevation angle. These problems are important to the SAR community because it will alleviate the cost to create the dictionary and reduce the number of elements in the dictionary needed for classication. In order to accomplish these tasks, we utilize the glint phenomenology, which is usually viewed as a hindrance in most algorithms but is valuable information in our research. One way to capitalize on the glint information is to predict the location of the int by using geometry of the single and double bounce phenomenology. After qualitative examination of the results, we were able to deduce that the geometry information was sucient for accurately predicting the location of the glint. Another way that we exploited the glint characteristics was by using it to extract the angle feature which we will use to do the pose estimation. Using this technique we were able to predict the cardinal heading of the vehicle within +/-2° with 96:6% having 0° error. Now this research will have an impact on the classication of SAR images because the geometric prediction will reduce the cost and time to develop and maintain the database for SAR ATR systems and the pose estimation will reduce the computational time and improve accuracy of vehicle classication.

  9. Effects of Emotionally Charged Auditory Stimulation on Gait Performance in the Elderly: A Preliminary Study

    PubMed Central

    Rizzo, John-Ross; Raghavan, Preeti; McCrery, J.R.; Oh-Park, Mooyeon; Verghese, Joe

    2015-01-01

    Objectives To evaluate the effect of a novel divided attention task—walking under auditory constraints—on gait performance in older adults and to determine whether this effect was moderated by cognitive status. Design Validation cohort. Setting General community. Participants Ambulatory older adults without dementia (N=104). Interventions Not applicable. Main Outcome Measures In this pilot study, we evaluated walking under auditory constraints in 104 older adults who completed 3 pairs of walking trials on a gait mat under 1 of 3 randomly assigned conditions: 1 pair without auditory stimulation and 2 pairs with emotionally charged auditory stimulation with happy or sad sounds. Results The mean age of subjects was 80.6±4.9 years, and 63% (n=66) were women. The mean velocity during normal walking was 97.9±20.6cm/s, and the mean cadence was 105.1±9.9 steps/min. The effect of walking under auditory constraints on gait characteristics was analyzed using a 2-factorial analysis of variance with a 1-between factor (cognitively intact and minimal cognitive impairment groups) and a 1-within factor (type of auditory stimuli). In both happy and sad auditory stimulation trials, cognitively intact older adults (n=96) showed an average increase of 2.68cm/s in gait velocity (F1.86,191.71=3.99; P=.02) and an average increase of 2.41 steps/min in cadence (F1.75,180.42=10.12; P<.001) as compared with trials without auditory stimulation. In contrast, older adults with minimal cognitive impairment (Blessed test score, 5–10; n=8) showed an average reduction of 5.45cm/s in gait velocity (F1.87,190.83=5.62; P=.005) and an average reduction of 3.88 steps/min in cadence (F1.79,183.10=8.21; P=.001) under both auditory stimulation conditions. Neither baseline fall history nor performance of activities of daily living accounted for these differences. Conclusions Our results provide preliminary evidence of the differentiating effect of emotionally charged auditory stimuli on gait

  10. Estimation of inferential uncertainty in assessing expert segmentation performance from STAPLE.

    PubMed

    Commowick, Olivier; Warfield, Simon K

    2009-01-01

    The evaluation of the quality of segmentations of an image, and the assessment of intra- and inter-expert variability in segmentation performance, has long been recognized as a difficult task. Recently an Expectation Maximization (EM) algorithm for Simultaneous Truth and Performance Level Estimation (STAPLE), Was developed to compute both an estimate of the reference standard segmentation and performance parameters from a set of segmentations of an image. The performance is characterized by the rate of detection of each segmentation label by each expert in comparison to the estimated reference standard. This previous work provides estimates of performance parameters, but does not provide any information regarding their uncertainty. An estimate of this inferential uncertainty, if available, would allow estimation of confidence intervals for the values of the parameters, aid in the interpretation of the performance of segmentation generators, and help determine if sufficient data size and number of segmentations have been obtained to accurately characterize the performance parameters. We present a new algorithm to estimate the inferential uncertainty of the performance parameters for binary segmentations. It is derived for the special case of the STAPLE algorithm based on established theory for general purpose covariance matrix estimation for EM algorithms. The bounds on performance estimates are estimated by the computation of the observed Information Matrix. We use this algorithm to study the bounds on performance estimates from simulated images with specified performance parameters, and from interactive segmentations of neonatal brain MRIs. We demonstrate that confidence intervals for expert segmentation performance parameters can be estimated with our algorithm. We investigate the influence of the number of experts and of the image size on these bounds, showing that it is possible to determine the number of image segmentations and the size of images necessary to

  11. Preliminary trial of augmented reality performed on a laparoscopic left hepatectomy.

    PubMed

    Phutane, Priyanka; Buc, Emmanuel; Poirot, Karine; Ozgur, Erol; Pezet, Denis; Bartoli, Adrien; Le Roy, Bertrand

    2017-08-08

    Laparoscopic liver surgery is seldom performed, mainly because of the risk of hepatic vein bleeding or incomplete resection of the tumour. This risk may be reduced by means of an augmented reality guidance system (ARGS), which have the potential to aid one in finding the position of intrahepatic tumours and hepatic veins and thus in facilitating the oncological resection and in limiting the risk of operative bleeding. We report the case of an 81-year-old man who was diagnosed with a hepatocellular carcinoma after an intraabdominal bleeding. The preoperative CT scan did not show metastases. We describe our preferred approach for laparoscopic left hepatectomy with initial control of the left hepatic vein and preliminary results of our novel ARGS achieved postoperatively. In our ARGS, a 3D virtual anatomical model is created from the abdominal CT scan and manually registered to selected laparoscopic images. For this patient, the virtual model was composed of the segmented left liver, right liver, tumour and median hepatic vein. The patient's operating time was summed up to 205 min where a blood loss of 300 cc was recorded. The postoperative course was simple. Histopathological analysis revealed the presence of a hepatocellular carcinoma with free margins. Our results of intrahepatic visualization suggest that ARGS can be beneficial in detecting the tumour, transection plane and medial hepatic vein prior to parenchymal transection, where it does not work due to the substantial changes to the liver's shape. As of today, we have performed eight similar left hepatectomies, with good results. Our ARGS has shown promising results and should now be attempted intraoperatively.

  12. A Method to Estimate Fabric Particle Penetration Performance

    DTIC Science & Technology

    2014-09-08

    sheath flow rate of 3.0 lpm to insure a 1 -to-10 ratio as recommended by the manufacturer. Larger particles were measured using a TSI Model 3320...Velocity (from reference 6) NAWCADPAX/TIM-2014/43 41 APPENDIX A 10 1 10 2 10 3 10 4 10 -7 10 -6 10 - 5 10 -4 10 -3 10 -2 10 - 1 10 0 Particle...DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response

  13. Sensor Selection for Aircraft Engine Performance Estimation and Gas Path Fault Diagnostics

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.

    2015-01-01

    This paper presents analytical techniques for aiding system designers in making aircraft engine health management sensor selection decisions. The presented techniques, which are based on linear estimation and probability theory, are tailored for gas turbine engine performance estimation and gas path fault diagnostics applications. They enable quantification of the performance estimation and diagnostic accuracy offered by different candidate sensor suites. For performance estimation, sensor selection metrics are presented for two types of estimators including a Kalman filter and a maximum a posteriori estimator. For each type of performance estimator, sensor selection is based on minimizing the theoretical sum of squared estimation errors in health parameters representing performance deterioration in the major rotating modules of the engine. For gas path fault diagnostics, the sensor selection metric is set up to maximize correct classification rate for a diagnostic strategy that performs fault classification by identifying the fault type that most closely matches the observed measurement signature in a weighted least squares sense. Results from the application of the sensor selection metrics to a linear engine model are presented and discussed. Given a baseline sensor suite and a candidate list of optional sensors, an exhaustive search is performed to determine the optimal sensor suites for performance estimation and fault diagnostics. For any given sensor suite, Monte Carlo simulation results are found to exhibit good agreement with theoretical predictions of estimation and diagnostic accuracies.

  14. Sensor Selection for Aircraft Engine Performance Estimation and Gas Path Fault Diagnostics

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.; Rinehart, Aidan W.

    2016-01-01

    This paper presents analytical techniques for aiding system designers in making aircraft engine health management sensor selection decisions. The presented techniques, which are based on linear estimation and probability theory, are tailored for gas turbine engine performance estimation and gas path fault diagnostics applications. They enable quantification of the performance estimation and diagnostic accuracy offered by different candidate sensor suites. For performance estimation, sensor selection metrics are presented for two types of estimators including a Kalman filter and a maximum a posteriori estimator. For each type of performance estimator, sensor selection is based on minimizing the theoretical sum of squared estimation errors in health parameters representing performance deterioration in the major rotating modules of the engine. For gas path fault diagnostics, the sensor selection metric is set up to maximize correct classification rate for a diagnostic strategy that performs fault classification by identifying the fault type that most closely matches the observed measurement signature in a weighted least squares sense. Results from the application of the sensor selection metrics to a linear engine model are presented and discussed. Given a baseline sensor suite and a candidate list of optional sensors, an exhaustive search is performed to determine the optimal sensor suites for performance estimation and fault diagnostics. For any given sensor suite, Monte Carlo simulation results are found to exhibit good agreement with theoretical predictions of estimation and diagnostic accuracies.

  15. Nonparametric EROC analysis for observer performance evaluation on joint detection and estimation tasks

    NASA Astrophysics Data System (ADS)

    Wunderlich, Adam; Goossens, Bart

    2014-03-01

    The majority of the literature on task-based image quality assessment has focused on lesion detection tasks, using the receiver operating characteristic (ROC) curve, or related variants, to measure performance. However, since many clinical image evaluation tasks involve both detection and estimation (e.g., estimation of kidney stone composition, estimation of tumor size), there is a growing interest in performance evaluation for joint detection and estimation tasks. To evaluate observer performance on such tasks, Clarkson introduced the estimation ROC (EROC) curve, and the area under the EROC curve as a summary figure of merit. In the present work, we propose nonparametric estimators for practical EROC analysis from experimental data, including estimators for the area under the EROC curve and its variance. The estimators are illustrated with a practical example comparing MRI images reconstructed from different k-space sampling trajectories.

  16. Preliminary performance assessment of biotoxin detection for UWS applications using a MicroChemLab device.

    SciTech Connect

    VanderNoot, Victoria A.; Haroldsen, Brent L.; Renzi, Ronald F.; Shokair, Isaac R.

    2010-03-01

    In a multiyear research agreement with Tenix Investments Pty. Ltd., Sandia has been developing field deployable technologies for detection of biotoxins in water supply systems. The unattended water sensor or UWS employs microfluidic chip based gel electrophoresis for monitoring biological analytes in a small integrated sensor platform. This instrument collects, prepares, and analyzes water samples in an automated manner. Sample analysis is done using the {mu}ChemLab{trademark} analysis module. This report uses analysis results of two datasets collected using the UWS to estimate performance of the device. The first dataset is made up of samples containing ricin at varying concentrations and is used for assessing instrument response and detection probability. The second dataset is comprised of analyses of water samples collected at a water utility which are used to assess the false positive probability. The analyses of the two sets are used to estimate the Receiver Operating Characteristic or ROC curves for the device at one set of operational and detection algorithm parameters. For these parameters and based on a statistical estimate, the ricin probability of detection is about 0.9 at a concentration of 5 nM for a false positive probability of 1 x 10{sup -6}.

  17. Performance of mean-frequency estimators for Doppler radar and lidar

    NASA Technical Reports Server (NTRS)

    Frehlich, R. G.; Yadlowsky, M. J.

    1994-01-01

    The performance of mean-frequency estimators for Doppler radar and lidar measurements of winds is presented in terms of two basic parameters: Phi, the ratio of the average signal energy per estimate to the spectral noise level; and Omega, which is proportional to the number of independent samples per estimate. For fixed Phi and Omega, the Cramer-Rao bound (CRB) (theoretical best performance) for unbiased estimators of mean frequency (normalized by the spectral width of the signal), signal power, and spectral width are essentially independent of the number of data samples M. For large Phi, the estimators of mean frequency are unbiased and the performance is independent of M. The spectral domain estimators and covariance based estimators are bounded by the approximate period of M. The spectral domain estimators and covariance based estimators are bounded by the approximate periodogram CRB. The standard deviation of the maximum-likelihood estimator approaches the exact CRB, which can be more than a factor of 2 better than the performance of the spectral domain estimators or covariance-based estimators for typical Omega. For small Phi, the estimators are biased due to the effects of the uncorrelated noise (white noise), which results in uniformly distributed 'bad' estimates. The fraction of bad estimates is a function of Phi and M with weak dependence on the parameter Omega. Simple empirical models describe the standard deviation of the good estimates and the fraction of bad estimates. For Doppler lidar and for large Phi, better performance is obtained by using many low-energy pulses instead of one pulse with the same total energy. For small Phi, the converse is true.

  18. Comment Data Mining to Estimate Student Performance Considering Consecutive Lessons

    ERIC Educational Resources Information Center

    Sorour, Shaymaa E.; Goda, Kazumasa; Mine, Tsunenori

    2017-01-01

    The purpose of this study is to examine different formats of comment data to predict student performance. Having students write comment data after every lesson can reflect students' learning attitudes, tendencies and learning activities involved with the lesson. In this research, Latent Dirichlet Allocation (LDA) and Probabilistic Latent Semantic…

  19. Performance vs. Paper-And-Pencil Estimates of Cognitive Abilities.

    ERIC Educational Resources Information Center

    Arima, James K.

    Arima's Discrimination Learning Test (DLT) was reconfigured, made into a self-paced mode, and administered to potential recruits in order to determine if: (1) a previous study indicating a lack of difference in learning performance between white and nonwhites would hold up; and (2) the correlations between scores attained on the DLT and scores…

  20. Evaluating Value-Added Methods of Estimating of Teacher Performance

    ERIC Educational Resources Information Center

    Guarino, Cassandra M.; Reckase, Mark D.; Wooldridge, Jeffrey M.

    2011-01-01

    Accurate indicators of educational effectiveness are needed to advance national policy goals of raising student achievement and closing social/cultural based achievement gaps. If constructed and used appropriately, such indicators for both program evaluation and the evaluation of teacher and school performance could have a transformative effect on…

  1. Estimating the Performance of a Concentrating Solar Array

    NASA Technical Reports Server (NTRS)

    French, E. P.; Mills, M. W.; Backovsky, Z.

    1985-01-01

    Comprehensive mathematical-analysis technique developed for array of solar-photovoltaic panels equipped with truncated-pyramid concentrators. Hollow pyramidal concentrator reflects Sunlight onto panel of photovoltaic cells. Comprehensive optical, thermal, and electrical analysis performed on array of units. Technique applicable, with modifications, to analysis and design of other multiple-cell reflecting photovoltaic systems.

  2. A National Estimate of Performance: Statewide Highway Safety Program Assessment.

    ERIC Educational Resources Information Center

    National Highway Traffic Safety Administration (DOT), Washington, DC.

    A nationwide systematic approach to assess the developments and achievements of highway safety activities was conducted to measure program outputs from 1969 through 1974 using key indicators of performance such as ratios and percentages. A sample of 10 states was selected with overall sample of 105 local jurisdictions which would provide estimated…

  3. Comment Data Mining to Estimate Student Performance Considering Consecutive Lessons

    ERIC Educational Resources Information Center

    Sorour, Shaymaa E.; Goda, Kazumasa; Mine, Tsunenori

    2017-01-01

    The purpose of this study is to examine different formats of comment data to predict student performance. Having students write comment data after every lesson can reflect students' learning attitudes, tendencies and learning activities involved with the lesson. In this research, Latent Dirichlet Allocation (LDA) and Probabilistic Latent Semantic…

  4. Bubble fusion: Preliminary estimates

    SciTech Connect

    Krakowski, R.A.

    1995-02-01

    The collapse of a gas-filled bubble in disequilibrium (i.e., internal pressure {much_lt} external pressure) can occur with a significant focusing of energy onto the entrapped gas in the form of pressure-volume work and/or acoustical shocks; the resulting heating can be sufficient to cause ionization and the emission of atomic radiations. The suggestion that extreme conditions necessary for thermonuclear fusion to occur may be possible has been examined parametrically in terms of the ratio of initial bubble pressure relative to that required for equilibrium. In this sense, the disequilibrium bubble is viewed as a three-dimensional ``sling shot`` that is ``loaded`` to an extent allowed by the maximum level of disequilibrium that can stably be achieved. Values of this disequilibrium ratio in the range 10{sup {minus}5}--10{sup {minus}6} are predicted by an idealized bubble-dynamics model as necessary to achieve conditions where nuclear fusion of deuterium-tritium might be observed. Harmonic and aharmonic pressurizations/decompressions are examined as means to achieve the required levels of disequilibrium required to create fusion conditions. A number of phenomena not included in the analysis reported herein could enhance or reduce the small levels of nuclear fusions predicted.

  5. LOD 1 VS. LOD 2 - Preliminary Investigations Into Differences in Mobile Rendering Performance

    NASA Astrophysics Data System (ADS)

    Ellul, C.; Altenbuchner, J.

    2013-09-01

    The increasing availability, size and detail of 3D City Model datasets has led to a challenge when rendering such data on mobile devices. Understanding the limitations to the usability of such models on these devices is particularly important given the broadening range of applications - such as pollution or noise modelling, tourism, planning, solar potential - for which these datasets and resulting visualisations can be utilized. Much 3D City Model data is created by extrusion of 2D topographic datasets, resulting in what is known as Level of Detail (LoD) 1 buildings - with flat roofs. However, in the UK the National Mapping Agency (the Ordnance Survey, OS) is now releasing test datasets to Level of Detail (LoD) 2 - i.e. including roof structures. These datasets are designed to integrate with the LoD 1 datasets provided by the OS, and provide additional detail in particular on larger buildings and in town centres. The availability of such integrated datasets at two different Levels of Detail permits investigation into the impact of the additional roof structures (and hence the display of a more realistic 3D City Model) on rendering performance on a mobile device. This paper describes preliminary work carried out to investigate this issue, for the test area of the city of Sheffield (in the UK Midlands). The data is stored in a 3D spatial database as triangles and then extracted and served as a web-based data stream which is queried by an App developed on the mobile device (using the Android environment, Java and OpenGL for graphics). Initial tests have been carried out on two dataset sizes, for the city centre and a larger area, rendering the data onto a tablet to compare results. Results of 52 seconds for rendering LoD 1 data, and 72 seconds for LoD 1 mixed with LoD 2 data, show that the impact of LoD 2 is significant.

  6. Estimating explosive performance from laser-induced shock waves

    NASA Astrophysics Data System (ADS)

    Gottfried, Jennifer

    2015-06-01

    A laboratory-scale method for predicting explosive performance (e.g., detonation velocity and pressure) based on milligram quantities of material is currently being developed. This technique is based on schlieren imaging of the shock wave generated in air by the formation of a laser-induced plasma on the surface of an energetic material. A large suite of pure and composite conventional energetic materials has been tested. Based on the observed linear correlation between the laser-induced shock velocity and the measured performance from full-scale detonation testing, this method is a potential screening tool for the development of new energetic materials and formulations prior to detonation testing. Recent results on the extension of this method to metal-containing energetic materials will be presented.

  7. Estimation of usefulness of positron emission tomography (PET) in the diagnosis of post-traumatic stress disorders--preliminary report.

    PubMed

    Wojtłowska-Wiechetek, D; Tworus, R; Dziuk, M; Petrovic, A; Szymańska, S; Zbyszewski, M; Ilnicki, S; Krzesiński, P

    2013-01-01

    The aim of this study was to evaluate the possibility of using PET both in assessing the susceptibility to stress and in the diagnosis of post-traumatic stress disorders. Mentally and somatically healthy soldiers were subjected to PET-CT head scan examinations before and after virtual reality stimulation with warfare scenarios. Despite stimulation of peripheral nervous system after 10 minutes, VR exposure in any of the examined soldiers simulation did not cause changes in any brain structure that was visualized in PET. PET-CT head scan was also performed in patients with typical symptoms of acute PTSD according to the criteria of DSM IV TR. In those patients no changes in any brain structure was found. Initially it was found that VR exposure techniques like clinically typical acute symptoms of PTSD do not leave changes in CNS, which could be visualized in PET. The preliminary hypothesis was put forward that exposure to stimuli like symptoms of PTSD must remain long enough to induce permanent damage of brain structure.

  8. A Graphical Method for Estimating Ion-Rocket Performance

    NASA Technical Reports Server (NTRS)

    Reynolds, Thaine W.; Childs, J. Howard

    1960-01-01

    Equations relating the critical temperature and ion current density for surface ionization of cesium on tungsten are derived for the cases of zero and finite electric fields at the ion-emitting surface. These equations are used to obtain a series of graphs that can be used to solve many problems relating to ion-rocket theoretical performance. The effect of operation at less than space-charge-limited current density and the effect of nonuniform propellant flux onto the ion-emitting surface are also treated.

  9. On the statistical performance of Granger-causal connectivity estimators.

    PubMed

    Sameshima, Koichi; Takahashi, Daniel Y; Baccalá, Luiz A

    2015-06-01

    In this article, we extend the statistical detection performance evaluation of linear connectivity from Sameshima et al. (in: Slezak et al. (eds.) Lecture Notes in Computer Science, 2014) via brand new Monte Carlo simulations of three widely used toy models under different data record lengths for a classic time domain multivariate Granger causality test, information partial directed coherence, information directed transfer function, and include conditional multivariate Granger causality whose behaviour was found to be anomalous.

  10. Rainfall estimation with a commercial tool for satellite internet in Ka band: concept and preliminary data analysis

    NASA Astrophysics Data System (ADS)

    Mugnai, Clio; Cuccoli, Fabrizio; Sermi, Francesco

    2014-10-01

    This work presents a real time method for rainfall estimation based on attenuation data acquired via Ka-band satellite link and discusses some results of its application. Data to be processed are recorded with a commercial kit for satellite web supplied by a European provider and operating above the urban area of Florence (Italy). Since the system automatically performs a continuous adjustment of the transmitted power in function of the intensity of the received signal, this information is being exploited to estimate the entity of the precipitation within the area. The adopted model for the attenuation of a microwave link due to hydrometeors is the one suggested by Olsen and Hodge and recommended by the ITU. The results are interpreted together with registered rain-rate measurements provided by three rain gauges dislocated within the area.

  11. Performance of different detrending methods in turbulent flux estimation

    NASA Astrophysics Data System (ADS)

    Donateo, Antonio; Cava, Daniela; Contini, Daniele

    2015-04-01

    The eddy covariance is the most direct, efficient and reliable method to measure the turbulent flux of a scalar (Baldocchi, 2003). Required conditions for high-quality eddy covariance measurements are amongst others stationarity of the measured data and a fully developed turbulence. The simplest method for obtaining the fluctuating components for covariance calculation according to Reynolds averaging rules under ideal stationary conditions is the so called mean removal method. However steady state conditions rarely exist in the atmosphere, because of the diurnal cycle, changes in meteorological conditions, or sensor drift. All these phenomena produce trends or low-frequency changes superimposed to the turbulent signal. Different methods for trend removal have been proposed in literature; however a general agreement on how separate low frequency perturbations from turbulence has not yet been reached. The most commonly applied methods are the linear detrending (Gash and Culf, 1996) and the high-pass filter, namely the moving average (Moncrieff et al., 2004). Moreover Vickers and Mahrt (2003) proposed a multi resolution decomposition method in order to select an appropriate time scale for mean removal as a function of atmospheric stability conditions. The present work investigates the performance of these different detrending methods in removing the low frequency contribution to the turbulent fluxes calculation, including also a spectral filter by a Fourier decomposition of the time series. The different methods have been applied to the calculation of the turbulent fluxes for different scalars (temperature, ultrafine particles number concentration, carbon dioxide and water vapour concentration). A comparison of the detrending methods will be performed also for different measurement site, namely a urban site, a suburban area, and a remote area in Antarctica. Moreover the performance of the moving average in detrending time series has been analyzed as a function of the

  12. Estimating Driver Performance Using Multiple Electroencephalography (EEG)-Based Regression Algorithms

    DTIC Science & Technology

    2014-09-01

    Estimating Driver Performance Using Multiple Electroencephalography (EEG)-Based Regression Algorithms by Gregory Apker, Brent Lance, Scott...Proving Ground, MD 21005-5425 ARL-TR-7074 September 2014 Estimating Driver Performance Using Multiple Electroencephalography (EEG)-Based... Electroencephalography (EEG)- Based Regression Algorithms 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Gregory Apker

  13. [Development of key indicators for nurses performance evaluation and estimation of their weights for management by objectives].

    PubMed

    Lee, Eun Hwa; Ahn, Sung Hee

    2010-02-01

    This methodological research was designed to develop performance evaluation key indicators (PEKIs) for management by objectives (MBO) and to estimate their weights for hospital nurses. The PEKIs were developed by selecting preliminary indicators from a literature review, examining content validity and identifying their level of importance. Data were collected from November 14, 2007 to February 18, 2008. Data set for importance of indicators was obtained from 464 nurses and weights of PEKIs domain was from 453 nurses, who worked for at least 2 yr in one of three hospitals. Data were analyzed using X(2)-test, factor analysis, and the Analytical Hierarchy Process. Based upon Content Validity Index of .8 or above, 61 indicators were selected from the 100 preliminary indicators. Finally, 40 PEKIs were developed from the 61 indicators, and categorized into 10 domains. The highest weight of the 10 domains was customer satisfaction, which was followed by patient education, direct nursing care, profit increase, safety management, improvement of nursing quality, completeness of nursing records, enhancing competence of nurses, indirect nursing care, and cost reduction, in that order. PEKIs and their weights can be utilized for impartial evaluation and MBO for hospital nurses. Further research to verify PEKIs would lead to successful implementation of MBO.

  14. Student Performance in Curricula Centered on Simulation-Based Inference: A Preliminary Report

    ERIC Educational Resources Information Center

    Chance, Beth; Wong, Jimmy; Tintle, Nathan

    2016-01-01

    "Simulation-based inference" (e.g., bootstrapping and randomization tests) has been advocated recently with the goal of improving student understanding of statistical inference, as well as the statistical investigative process as a whole. Preliminary assessment data have been largely positive. This article describes the analysis of the…

  15. Age estimation by pulp-to-tooth area ratio using cone-beam computed tomography: A preliminary analysis

    PubMed Central

    Rai, Arpita; Acharya, Ashith B.; Naikmasur, Venkatesh G.

    2016-01-01

    Background: Age estimation of living or deceased individuals is an important aspect of forensic sciences. Conventionally, pulp-to-tooth area ratio (PTR) measured from periapical radiographs have been utilized as a nondestructive method of age estimation. Cone-beam computed tomography (CBCT) is a new method to acquire three-dimensional images of the teeth in living individuals. Aims: The present study investigated age estimation based on PTR of the maxillary canines measured in three planes obtained from CBCT image data. Settings and Design: Sixty subjects aged 20–85 years were included in the study. Materials and Methods: For each tooth, mid-sagittal, mid-coronal, and three axial sections—cementoenamel junction (CEJ), one-fourth root level from CEJ, and mid-root—were assessed. PTR was calculated using AutoCAD software after outlining the pulp and tooth. Statistical Analysis Used: All statistical analyses were performed using an SPSS 17.0 software program. Results and Conclusions: Linear regression analysis showed that only PTR in axial plane at CEJ had significant age correlation (r = 0.32; P < 0.05). This is probably because of clearer demarcation of pulp and tooth outline at this level. PMID:28123269

  16. Motor unit loss estimation by the multipoint incremental MUNE method in children with spinal muscular atrophy--a preliminary study.

    PubMed

    Gawel, Malgorzata; Kostera-Pruszczyk, Anna; Lusakowska, Anna; Jedrzejowska, Maria; Ryniewicz, Barbara; Lipowska, Marta; Gawel, Damian; Kaminska, Anna

    2015-03-01

    Quantitative EMG reflects denervation of muscles after lower motor neuron degeneration in spinal muscular atrophy (SMA) but does not reflect actual motor unit loss. The aim of our study was to assess the value of the multipoint incremental motor unit number estimation (MUNE) method in the modification by Shefner in estimating motor unit loss in SMA. The number of motor units, the mean amplitude of an average surface-detected single motor unit potential (SMUP), and the amplitude of compound motor action potentials (CMAP) were estimated in 14 children with SMA in the abductor pollicis brevis (ABP). Significant differences in MUNE values and SMUP and CMAP amplitude were found between the SMA and control groups (P < 0.0001). MUNE values correlated with Hammersmith Functional Motor Scale (HFMS) scores (P < 0.05). Increased SMUP amplitude values correlated with decreased HFMS scores (P < 0.05). The study confirms that MUNE method in the modification by Shefner is a useful tool reflecting motor unit loss in SMA, and it is easy to perform and well tolerated. MUNE and SMUP amplitude seemed to be sensitive parameters reflecting motor dysfunction in SMA but a longitudinal study in a larger number of subjects is needed.

  17. The Spacecraft Materials Selector: An Artificial Intelligence System for Preliminary Design Trade Studies, Materials Assessments, and Estimates of Environments Present

    NASA Technical Reports Server (NTRS)

    Pippin, H. G.; Woll, S. L. B.

    2000-01-01

    Institutions need ways to retain valuable information even as experienced individuals leave an organization. Modern electronic systems have enough capacity to retain large quantities of information that can mitigate the loss of experience. Performance information for long-term space applications is relatively scarce and specific information (typically held by a few individuals within a single project) is often rather narrowly distributed. Spacecraft operate under severe conditions and the consequences of hardware and/or system failures, in terms of cost, loss of information, and time required to replace the loss, are extreme. These risk factors place a premium on appropriate choice of materials and components for space applications. An expert system is a very cost-effective method for sharing valuable and scarce information about spacecraft performance. Boeing has an artificial intelligence software package, called the Boeing Expert System Tool (BEST), to construct and operate knowledge bases to selectively recall and distribute information about specific subjects. A specific knowledge base to evaluate the on-orbit performance of selected materials on spacecraft has been developed under contract to the NASA SEE program. The performance capabilities of the Spacecraft Materials Selector (SMS) knowledge base are described. The knowledge base is a backward-chaining, rule-based system. The user answers a sequence of questions, and the expert system provides estimates of optical and mechanical performance of selected materials under specific environmental conditions. The initial operating capability of the system will include data for Kapton, silverized Teflon, selected paints, silicone-based materials, and certain metals. For situations where a mission profile (launch date, orbital parameters, mission duration, spacecraft orientation) is not precisely defined, the knowledge base still attempts to provide qualitative observations about materials performance and likely

  18. The Spacecraft Materials Selector: An Artificial Intelligence System for Preliminary Design Trade Studies, Materials Assessments, and Estimates of Environments Present

    NASA Technical Reports Server (NTRS)

    Pippin, H. G.; Woll, S. L. B.

    2000-01-01

    Institutions need ways to retain valuable information even as experienced individuals leave an organization. Modern electronic systems have enough capacity to retain large quantities of information that can mitigate the loss of experience. Performance information for long-term space applications is relatively scarce and specific information (typically held by a few individuals within a single project) is often rather narrowly distributed. Spacecraft operate under severe conditions and the consequences of hardware and/or system failures, in terms of cost, loss of information, and time required to replace the loss, are extreme. These risk factors place a premium on appropriate choice of materials and components for space applications. An expert system is a very cost-effective method for sharing valuable and scarce information about spacecraft performance. Boeing has an artificial intelligence software package, called the Boeing Expert System Tool (BEST), to construct and operate knowledge bases to selectively recall and distribute information about specific subjects. A specific knowledge base to evaluate the on-orbit performance of selected materials on spacecraft has been developed under contract to the NASA SEE program. The performance capabilities of the Spacecraft Materials Selector (SMS) knowledge base are described. The knowledge base is a backward-chaining, rule-based system. The user answers a sequence of questions, and the expert system provides estimates of optical and mechanical performance of selected materials under specific environmental conditions. The initial operating capability of the system will include data for Kapton, silverized Teflon, selected paints, silicone-based materials, and certain metals. For situations where a mission profile (launch date, orbital parameters, mission duration, spacecraft orientation) is not precisely defined, the knowledge base still attempts to provide qualitative observations about materials performance and likely

  19. A Preliminary Assessment of the S-3A SRAL Performances in SAR Mode

    NASA Astrophysics Data System (ADS)

    Dinardo, Salvatore; Scharroo, Remko; Bonekamp, Hans; Lucas, Bruno; Loddo, Carolina; Benveniste, Jerome

    2016-08-01

    The present work aims to assess and characterize the S3-A SRAL Altimeter performance in closed-loop tracking mode and in open ocean conditions. We have processed the Sentinel-3 SAR data products from L0 until L2 using an adaptation of the ESRIN GPOD CryoSat-2 Processor SARvatore.During the Delay-Doppler processing, we have chosen to activate the range zero-padding option.The L2 altimetric geophysical parameters, that are to be validated, are the sea surface height above the ellipsoid (SSH), sea level anomaly (SLA), the significant wave height (SWH) and wind speed (U10), all estimated at 20 Hz.The orbit files are the POD MOE, while the geo- corrections are extracted from the RADS database.In order to assess the accuracy of the wave&wind products, we have been using an ocean wave&wind speed model output (wind speed at 10 meter high above the sea surface) from the ECMWF.We have made a first order approximation of the sea state bias as -4.7% of the SWH.In order to assess the precision performance of SRAL SAR mode, we compute the level of instrumental noise (range, wave height and wind speed) for different conditions of sea state.

  20. West Village Community: Quality Management Processes and Preliminary Heat Pump Water Heater Performance

    SciTech Connect

    Dakin, B.; Backman, C.; Hoeschele, M.; German, A.

    2012-11-01

    West Village, a multi-use project underway at the University of California Davis, represents a ground-breaking sustainable community incorporating energy efficiency measures and on-site renewable generation to achieve community-level Zero Net Energy (ZNE) goals. The project when complete will provide housing for students, faculty, and staff with a vision to minimize the community's impact on energy use by reducing building energy use, providing on-site generation, and encouraging alternative forms of transportation. This focus of this research is on the 192 student apartments that were completed in 2011 under Phase I of the West Village multi-year project. The numerous aggressive energy efficiency measures implemented result in estimated source energy savings of 37% over the B10 Benchmark. There are two primary objectives of this research. The first is to evaluate performance and efficiency of the central heat pump water heaters as a strategy to provide efficient electric water heating for net-zero all-electric buildings and where natural gas is not available on site. In addition, effectiveness of the quality assurance and quality control processes implemented to ensure proper system commissioning and to meet program participation requirements is evaluated. Recommendations for improvements that could improve successful implementation for large-scale, high performance communities are identified.

  1. West Village Community. Quality Management Processes and Preliminary Heat Pump Water Heater Performance

    SciTech Connect

    Dakin, B.; Backman, C.; Hoeschele, M.; German, A.

    2012-11-01

    West Village, a multi-use project underway at the University of California Davis, represents a ground-breaking sustainable community incorporating energy efficiency measures and on-site renewable generation to achieve community-level Zero Net Energy (ZNE) goals. When complete, the project will provide housing for students, faculty, and staff with a vision to minimize the community’s impact on energy use by reducing building energy use, providing on-site generation, and encouraging alternative forms of transportation. This focus of this research is on the 192 student apartments that were completed in 2011 under Phase I of the West Village multi-year project. The numerous aggressive energy efficiency measures implemented result in estimated source energy savings of 37% over the B10 Benchmark. There are two primary objectives of this research. The first is to evaluate performance and efficiency of the central heat pump water heaters as a strategy to provide efficient electric water heating for net-zero all-electric buildings and where natural gas is not available on site. In addition, effectiveness of the quality assurance and quality control processes implemented to ensure proper system commissioning and to meet program participation requirements is evaluated. Recommendations for improvements that could improve successful implementation for large-scale, high performance communities are identified.

  2. Preliminary Investigation of a Translating Cowl Technique for Improving Take-off Performance of a Sharp-lip Supersonic Diffuser

    NASA Technical Reports Server (NTRS)

    Cortright, Edgar M , Jr

    1951-01-01

    A preliminary investigation was conducted in quiescent air on a translating cowl technique for improving the take-off performance of a sharp-lip supersonic diffuser. The technique consists of cutting the cowling in a plane normal to its axis and then translating the forepart of the cowling in the forward direction. The leading edge of the fixed portion of the cowling is rounded. Appreciable improved inlet performance was obtained with a cowling translation corresponding to a gap of only 1/4 inlet radius.

  3. Performance characteristics of DRI, CEDIA, and REMEDi systems for preliminary tests of amphetamines and opiates in human urine.

    PubMed

    Huang, Min-Kun; Dai, Yu-Shan; Lee, Choung-Huei; Liu, Chiareiy; Tsay, Wen-Ing; Li, Jih-Heng

    2006-01-01

    Arrestee urine specimens (930) were tested with DRI, CEDIA, and REMEDi; those that tested positive for amphetamines and opiates (616 and 414, respectively) were then confirmed by gas chromatography-mass spectrometry. The performance characteristics of these three preliminary systems were evaluated using the following commonly used parameters: true positive, true negative, false positive, and false negative. The sensitivity, specificity, and efficiency of these methods were also calculated. Data derived from this study indicated DRI and CEDIA adapted by this study generated acceptable preliminary test results for amphetamine/methamphetamine and morphine/codeine, but not for MDA/MDMA and REMEDi has lower sensitivity than DRI and CEDIA, but with better specificity and efficiency, supporting its use under emergency room settings where drug concentrations in overdose cases are expectedly at high levels.

  4. A Systematic Approach for Model-Based Aircraft Engine Performance Estimation

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.; Garg, Sanjay

    2010-01-01

    A requirement for effective aircraft engine performance estimation is the ability to account for engine degradation, generally described in terms of unmeasurable health parameters such as efficiencies and flow capacities related to each major engine module. This paper presents a linear point design methodology for minimizing the degradation-induced error in model-based aircraft engine performance estimation applications. The technique specifically focuses on the underdetermined estimation problem, where there are more unknown health parameters than available sensor measurements. A condition for Kalman filter-based estimation is that the number of health parameters estimated cannot exceed the number of sensed measurements. In this paper, the estimated health parameter vector will be replaced by a reduced order tuner vector whose dimension is equivalent to the sensed measurement vector. The reduced order tuner vector is systematically selected to minimize the theoretical mean squared estimation error of a maximum a posteriori estimator formulation. This paper derives theoretical estimation errors at steady-state operating conditions, and presents the tuner selection routine applied to minimize these values. Results from the application of the technique to an aircraft engine simulation are presented and compared to the estimation accuracy achieved through conventional maximum a posteriori and Kalman filter estimation approaches. Maximum a posteriori estimation results demonstrate that reduced order tuning parameter vectors can be found that approximate the accuracy of estimating all health parameters directly. Kalman filter estimation results based on the same reduced order tuning parameter vectors demonstrate that significantly improved estimation accuracy can be achieved over the conventional approach of selecting a subset of health parameters to serve as the tuner vector. However, additional development is necessary to fully extend the methodology to Kalman filter

  5. Estimation of inferential uncertainty in assessing expert segmentation performance from STAPLE.

    PubMed

    Commowick, Olivier; Warfield, Simon K

    2010-03-01

    The evaluation of the quality of segmentations of an image, and the assessment of intra- and inter-expert variability in segmentation performance, has long been recognized as a difficult task. For a segmentation validation task, it may be effective to compare the results of an automatic segmentation algorithm to multiple expert segmentations. Recently an expectation-maximization (EM) algorithm for simultaneous truth and performance level estimation (STAPLE) was developed to this end to compute both an estimate of the reference standard segmentation and performance parameters from a set of segmentations of an image. The performance is characterized by the rate of detection of each segmentation label by each expert in comparison to the estimated reference standard. This previous work provides estimates of performance parameters,but does not provide any information regarding the uncertainty of the estimated values. An estimate of this inferential uncertainty, if available, would allow the estimation of confidence intervals for the values of the parameters. This would facilitate the interpretation of the performance of segmentation generators and help determine if sufficient data size and number of segmentations have been obtained to precisely characterize the performance parameters. We present a new algorithm to estimate the inferential uncertainty of the performance parameters for binary and multi-category segmentations. It is derived for the special case of the STAPLE algorithm based on established theory for general purpose covariance matrix estimation for EM algorithms. The bounds on the performance parameters are estimated by the computation of the observed information matrix.We use this algorithm to study the bounds on performance parameters estimates from simulated images with specified performance parameters, and from interactive segmentations of neonatal brain MRIs. We demonstrate that confidence intervals for expert segmentation performance parameters can be

  6. NPP Clouds and the Earth's Radiant Energy System (CERES) Predicted Sensor Performance Calibration and Preliminary Data Product Performance

    NASA Technical Reports Server (NTRS)

    Priestly, Kory; Smith, George L.; Thomas, Susan; Maddock, Suzanne L.

    2009-01-01

    characterization program benefited from the 30-year operational experience of the CERES EOS sensors, as well as a stronger emphasis of radiometric characterization in the Statement of Work with the sensor provider. Improvements to the pre-flight program included increased spectral, spatial, and temporal sampling under vacuum conditions as well as additional tests to characterize the primary and transfer standards in the calibration facility. Future work will include collaboration with NIST to further enhance the understanding of the radiometric performance of this equipment prior to flight. The current effort summarizes these improvements to the CERES FM-5 pre-flight sensor characterization program, as well as modifications to inflight calibration procedures and operational tasking. In addition, an estimate of the impacts to the system level accuracy and traceability is presented.

  7. NPP Clouds and the Earth's Radiant Energy System (CERES) Predicted Sensor Performance Calibration and Preliminary Data Product Performance

    NASA Technical Reports Server (NTRS)

    Priestly, Kory; Smith, George L.; Thomas, Susan; Maddock, Suzanne L.

    2009-01-01

    characterization program benefited from the 30-year operational experience of the CERES EOS sensors, as well as a stronger emphasis of radiometric characterization in the Statement of Work with the sensor provider. Improvements to the pre-flight program included increased spectral, spatial, and temporal sampling under vacuum conditions as well as additional tests to characterize the primary and transfer standards in the calibration facility. Future work will include collaboration with NIST to further enhance the understanding of the radiometric performance of this equipment prior to flight. The current effort summarizes these improvements to the CERES FM-5 pre-flight sensor characterization program, as well as modifications to inflight calibration procedures and operational tasking. In addition, an estimate of the impacts to the system level accuracy and traceability is presented.

  8. Children can accurately monitor and control their number-line estimation performance.

    PubMed

    Wall, Jenna L; Thompson, Clarissa A; Dunlosky, John; Merriman, William E

    2016-10-01

    Accurate monitoring and control are essential for effective self-regulated learning. These metacognitive abilities may be particularly important for developing math skills, such as when children are deciding whether a math task is difficult or whether they made a mistake on a particular item. The present experiments investigate children's ability to monitor and control their math performance. Experiment 1 assessed task- and item-level monitoring while children performed a number line estimation task. Children in 1st, 2nd, and 4th grade (N = 59) estimated the location of numbers on small- and large-scale number lines and judged their confidence in each estimate. Consistent with their performance, children were more confident in their small-scale estimates than their large-scale estimates. Experiments 2 (N = 54) and 3 (N = 85) replicated this finding in new samples of 1st, 2nd, and 4th graders and assessed task- and item-level control. When asked which estimates they wanted the experimenter to evaluate for a reward, children tended to select estimates associated with lower error and higher confidence. Thus, children can accurately monitor their performance during number line estimation and use their monitoring to control their subsequent performance. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  9. Reading based IQ estimates and actual premorbid cognitive performance: discrepancies in a college athlete sample.

    PubMed

    Rabinowitz, Amanda R; Arnett, Peter A

    2012-01-01

    The present study sought to evaluate the Wechsler Test of Adult Reading (WTAR) Full-Scale IQ (FSIQ) estimate as an index of premorbid ability in a sample 574 of healthy college athletes participating in a sports concussion management program. We compared baseline neuropsychological test performance with the WTAR FSIQ estimate obtained at baseline. Results revealed that the discrepancy between actual neuropsychological test scores and the WTAR FSIQ estimate was greatest for those with estimated FSIQs greater than 107. The clinical implication of this finding was evaluated in the 51 participants who went on to sustain a concussion. For individuals with higher IQ estimates, the WTAR estimate obtained post-concussion suggested greater post-concussion decline than that indicated by comparison with actual baseline neuropsychological performance.

  10. Percentile-based Empirical Distribution Function Estimates for Performance Evaluation of Healthcare Providers

    PubMed Central

    Paddock, Susan M.; Louis, Thomas A.

    2010-01-01

    Summary Hierarchical models are widely-used to characterize the performance of individual healthcare providers. However, little attention has been devoted to system-wide performance evaluations, the goals of which include identifying extreme (e.g., top 10%) provider performance and developing statistical benchmarks to define high-quality care. Obtaining optimal estimates of these quantities requires estimating the empirical distribution function (EDF) of provider-specific parameters that generate the dataset under consideration. However, the difficulty of obtaining uncertainty bounds for a square-error loss minimizing EDF estimate has hindered its use in system-wide performance evaluations. We therefore develop and study a percentile-based EDF estimate for univariate provider-specific parameters. We compute order statistics of samples drawn from the posterior distribution of provider-specific parameters to obtain relevant uncertainty assessments of an EDF estimate and its features, such as thresholds and percentiles. We apply our method to data from the Medicare End Stage Renal Disease (ESRD) Program, a health insurance program for people with irreversible kidney failure. We highlight the risk of misclassifying providers as exceptionally good or poor performers when uncertainty in statistical benchmark estimates is ignored. Given the high stakes of performance evaluations, statistical benchmarks should be accompanied by precision estimates. PMID:21918583

  11. Percentile-based Empirical Distribution Function Estimates for Performance Evaluation of Healthcare Providers.

    PubMed

    Paddock, Susan M; Louis, Thomas A

    2011-08-01

    Hierarchical models are widely-used to characterize the performance of individual healthcare providers. However, little attention has been devoted to system-wide performance evaluations, the goals of which include identifying extreme (e.g., top 10%) provider performance and developing statistical benchmarks to define high-quality care. Obtaining optimal estimates of these quantities requires estimating the empirical distribution function (EDF) of provider-specific parameters that generate the dataset under consideration. However, the difficulty of obtaining uncertainty bounds for a square-error loss minimizing EDF estimate has hindered its use in system-wide performance evaluations. We therefore develop and study a percentile-based EDF estimate for univariate provider-specific parameters. We compute order statistics of samples drawn from the posterior distribution of provider-specific parameters to obtain relevant uncertainty assessments of an EDF estimate and its features, such as thresholds and percentiles. We apply our method to data from the Medicare End Stage Renal Disease (ESRD) Program, a health insurance program for people with irreversible kidney failure. We highlight the risk of misclassifying providers as exceptionally good or poor performers when uncertainty in statistical benchmark estimates is ignored. Given the high stakes of performance evaluations, statistical benchmarks should be accompanied by precision estimates.

  12. Cryogenic irradiation of an EMCCD for the WFIRST coronagraph: preliminary performance analysis

    NASA Astrophysics Data System (ADS)

    Bush, Nathan; Hall, David; Holland, Andrew; Burgon, Ross; Murray, Neil; Gow, Jason; Jordan, Douglas; Demers, Richard; Harding, Leon K.; Nemati, Bijan; Hoenk, Michael; Michaels, Darren; Peddada, Pavani

    2016-08-01

    The Wide Field Infra-Red Survey Telescope (WFIRST) is a NASA observatory scheduled to launch in the next decade that will settle essential questions in exoplanet science. The Wide Field Instrument (WFI) offers Hubble quality imaging over a 0.28 square degree field of view and will gather NIR statistical data on exoplanets through gravitational microlensing. An on-board coronagraph will for the first time perform direct imaging and spectroscopic analysis of exoplanets with properties analogous to those within our own solar system, including cold Jupiters, mini Neptunes and potentially super Earths. The Coronagraph Instrument (CGI) will be required to operate with low signal flux for long integration times, demanding all noise sources are kept to a minimum. The Electron Multiplication (EM)-CCD has been baselined for both the imaging and spectrograph cameras due its ability to operate with sub-electron effective read noise values with appropriate multiplication gain setting. The presence of other noise sources, however, such as thermal dark signal and Clock Induced Charge (CIC), need to be characterized and mitigated. In addition, operation within a space environment will subject the device to radiation damage that will degrade the Charge Transfer Effciency (CTE) of the device throughout the mission lifetime. Irradiation at the nominal instrument operating temperature has the potential to provide the best estimate of performance degradation that will be experienced in-flight, since the final population of silicon defects has been shown to be dependent upon the temperature at which the sensor is irradiated. Here we present initial findings from pre- and post- cryogenic irradiation testing of the e2v CCD201-20 BI EMCCD sensor, baselined for the WFIRST coronagraph instrument. The motivation for irradiation at cryogenic temperatures is discussed with reference to previous investigations of a similar nature. The results are presented in context with those from a previous

  13. Optimal Tuner Selection for Kalman-Filter-Based Aircraft Engine Performance Estimation

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.; Garg, Sanjay

    2011-01-01

    An emerging approach in the field of aircraft engine controls and system health management is the inclusion of real-time, onboard models for the inflight estimation of engine performance variations. This technology, typically based on Kalman-filter concepts, enables the estimation of unmeasured engine performance parameters that can be directly utilized by controls, prognostics, and health-management applications. A challenge that complicates this practice is the fact that an aircraft engine s performance is affected by its level of degradation, generally described in terms of unmeasurable health parameters such as efficiencies and flow capacities related to each major engine module. Through Kalman-filter-based estimation techniques, the level of engine performance degradation can be estimated, given that there are at least as many sensors as health parameters to be estimated. However, in an aircraft engine, the number of sensors available is typically less than the number of health parameters, presenting an under-determined estimation problem. A common approach to address this shortcoming is to estimate a subset of the health parameters, referred to as model tuning parameters. The problem/objective is to optimally select the model tuning parameters to minimize Kalman-filterbased estimation error. A tuner selection technique has been developed that specifically addresses the under-determined estimation problem, where there are more unknown parameters than available sensor measurements. A systematic approach is applied to produce a model tuning parameter vector of appropriate dimension to enable estimation by a Kalman filter, while minimizing the estimation error in the parameters of interest. Tuning parameter selection is performed using a multi-variable iterative search routine that seeks to minimize the theoretical mean-squared estimation error of the Kalman filter. This approach can significantly reduce the error in onboard aircraft engine parameter estimation

  14. Computer code for estimating installed performance of aircraft gas turbine engines. Volume 1: Final report

    NASA Technical Reports Server (NTRS)

    Kowalski, E. J.

    1979-01-01

    A computerized method which utilizes the engine performance data is described. The method estimates the installed performance of aircraft gas turbine engines. This installation includes: engine weight and dimensions, inlet and nozzle internal performance and drag, inlet and nacelle weight, and nacelle drag.

  15. Computer code for estimating installed performance of aircraft gas turbine engines. Volume 2: Users manual

    NASA Technical Reports Server (NTRS)

    Kowalski, E. J.

    1979-01-01

    A computerized method which utilizes the engine performance data and estimates the installed performance of aircraft gas turbine engines is presented. This installation includes: engine weight and dimensions, inlet and nozzle internal performance and drag, inlet and nacelle weight, and nacelle drag. A user oriented description of the program input requirements, program output, deck setup, and operating instructions is presented.

  16. Preliminary Axial Flow Turbine Design and Off-Design Performance Analysis Methods for Rotary Wing Aircraft Engines. Part 1; Validation

    NASA Technical Reports Server (NTRS)

    Chen, Shu-cheng, S.

    2009-01-01

    For the preliminary design and the off-design performance analysis of axial flow turbines, a pair of intermediate level-of-fidelity computer codes, TD2-2 (design; reference 1) and AXOD (off-design; reference 2), are being evaluated for use in turbine design and performance prediction of the modern high performance aircraft engines. TD2-2 employs a streamline curvature method for design, while AXOD approaches the flow analysis with an equal radius-height domain decomposition strategy. Both methods resolve only the flows in the annulus region while modeling the impact introduced by the blade rows. The mathematical formulations and derivations involved in both methods are documented in references 3, 4 for TD2-2) and in reference 5 (for AXOD). The focus of this paper is to discuss the fundamental issues of applicability and compatibility of the two codes as a pair of companion pieces, to perform preliminary design and off-design analysis for modern aircraft engine turbines. Two validation cases for the design and the off-design prediction using TD2-2 and AXOD conducted on two existing high efficiency turbines, developed and tested in the NASA/GE Energy Efficient Engine (GE-E3) Program, the High Pressure Turbine (HPT; two stages, air cooled) and the Low Pressure Turbine (LPT; five stages, un-cooled), are provided in support of the analysis and discussion presented in this paper.

  17. Are Estimates of Meaningful Decline in Mobility Performance Consistent Among Clinically Important Subgroups? (Health ABC Study)

    PubMed Central

    Studenski, Stephanie; Newman, Anne; Simonsick, Eleanor; Harris, Tamara; Schwartz, Ann; Visser, Marjolein

    2014-01-01

    Background. Meaningful change criteria help determine if function has improved or declined, but their magnitudes may vary across clinically relevant subgroups. We estimate meaningful decline in four common measures of physical performance in subgroups of older adults based on initial performance, demographics, chronic conditions, and health status. Methods. We used baseline (Year 1) and Year 4 data from the Health, Aging and Body Composition (Health ABC) study, a well-functioning cohort at baseline of white and black men and women (age 70–79), to evaluate the magnitude of meaningful decline in performance (6 m gait speed, 400-m walk time (400MWT), Short Physical Performance Battery, and Health ABC Physical Performance Battery (PPB), based on self-reported perceived mobility anchors (climbing 10 steps and walking ¼ mile). Estimates were stratified by initial performance, demographics, health status, chronic conditions, and body mass index, and compared across strata. Results. For all four measures, small and substantial decline estimates were generally consistent among subgroups based on initial performance, demographics, health status, and chronic conditions. The only exception was for 400MWT, where men had greater estimates than women. For PPB, small change was 0.12 points, and substantial change was 0.22 points. Conclusions. Estimates of small and substantial meaningful decline resemble those previously reported for gait speed, 400MWT, and SPPB. Magnitudes of meaningful performance decline appear to be generally consistent across strata of initial performance, demographics, health status, body mass index, and chronic conditions. PMID:24615070

  18. Children's Performance Estimation in Mathematics and Science Tests over a School Year: A Pilot Study

    ERIC Educational Resources Information Center

    Roderer, Thomas; Roebers, Claudia M.

    2013-01-01

    Introduction: The metacognitve ability to accurately estimate ones performance in a test, is assumed to be of central importance for initializing task-oriented effort. In addition activating adequate problem-solving strategies, and engaging in efficient error detection and correction. Although school children's' ability to estimate their own…

  19. Estimating the Extreme Behaviors of Students Performance Using Quantile Regression--Evidences from Taiwan

    ERIC Educational Resources Information Center

    Chen, Sheng-Tung; Kuo, Hsiao-I.; Chen, Chi-Chung

    2012-01-01

    The two-stage least squares approach together with quantile regression analysis is adopted here to estimate the educational production function. Such a methodology is able to capture the extreme behaviors of the two tails of students' performance and the estimation outcomes have important policy implications. Our empirical study is applied to the…

  20. The Performance of the Full Information Maximum Likelihood Estimator in Multiple Regression Models with Missing Data.

    ERIC Educational Resources Information Center

    Enders, Craig K.

    2001-01-01

    Examined the performance of a recently available full information maximum likelihood (FIML) estimator in a multiple regression model with missing data using Monte Carlo simulation and considering the effects of four independent variables. Results indicate that FIML estimation was superior to that of three ad hoc techniques, with less bias and less…

  1. An Integrated Approach for Aircraft Engine Performance Estimation and Fault Diagnostics

    NASA Technical Reports Server (NTRS)

    imon, Donald L.; Armstrong, Jeffrey B.

    2012-01-01

    A Kalman filter-based approach for integrated on-line aircraft engine performance estimation and gas path fault diagnostics is presented. This technique is specifically designed for underdetermined estimation problems where there are more unknown system parameters representing deterioration and faults than available sensor measurements. A previously developed methodology is applied to optimally design a Kalman filter to estimate a vector of tuning parameters, appropriately sized to enable estimation. The estimated tuning parameters can then be transformed into a larger vector of health parameters representing system performance deterioration and fault effects. The results of this study show that basing fault isolation decisions solely on the estimated health parameter vector does not provide ideal results. Furthermore, expanding the number of the health parameters to address additional gas path faults causes a decrease in the estimation accuracy of those health parameters representative of turbomachinery performance deterioration. However, improved fault isolation performance is demonstrated through direct analysis of the estimated tuning parameters produced by the Kalman filter. This was found to provide equivalent or superior accuracy compared to the conventional fault isolation approach based on the analysis of sensed engine outputs, while simplifying online implementation requirements. Results from the application of these techniques to an aircraft engine simulation are presented and discussed.

  2. Estimating the Extreme Behaviors of Students Performance Using Quantile Regression--Evidences from Taiwan

    ERIC Educational Resources Information Center

    Chen, Sheng-Tung; Kuo, Hsiao-I.; Chen, Chi-Chung

    2012-01-01

    The two-stage least squares approach together with quantile regression analysis is adopted here to estimate the educational production function. Such a methodology is able to capture the extreme behaviors of the two tails of students' performance and the estimation outcomes have important policy implications. Our empirical study is applied to the…

  3. The climate change performance scorecard and carbon estimates for national forest

    Treesearch

    John W. Coulston; Kellen Nelson; Christopher W. Woodall; David Meriwether; Gregory A. Reams

    2012-01-01

    The U.S. Forest Service manages 20 percent of the forest land in the United States. Both the Climate Change Performance Scorecard and the revised National Forest Management Act require the assessment of carbon stocks on these lands. We present circa 2010 estimates of carbon stocks for each national forest and recommendations to improve these estimates.

  4. The Performance of the Full Information Maximum Likelihood Estimator in Multiple Regression Models with Missing Data.

    ERIC Educational Resources Information Center

    Enders, Craig K.

    2001-01-01

    Examined the performance of a recently available full information maximum likelihood (FIML) estimator in a multiple regression model with missing data using Monte Carlo simulation and considering the effects of four independent variables. Results indicate that FIML estimation was superior to that of three ad hoc techniques, with less bias and less…

  5. Chemical shoreline cleaning agents: Evaluation of two laboratory procedures for estimating performance

    SciTech Connect

    Clayton, J.B.; Tsang, S.F.; Frank, V.; Marsden, P.; Chau, N.

    1993-07-01

    The report presents data from studies designed to evaluate characteristics of selected bench-scale test methods for estimating cleaning performance of chemical agents for removal of oil from substrate surfaces. Such agents have the potential to be used to remove oil that might strand on shorelines and cause adverse effects to impacted ecosystems. In order to mitigate the effect of stranded oil with chemical cleaning agents, however, an on-scene coordinator must have information and an understanding of performance characteristics for available cleaning agents. Performance of candidate cleaning agents can be estimated on the basis of laboratory testing procedures that are designed to evaluate performance of different agents. Data presented in the report are intended to assist the U.S. EPA in evaluation of candidate test methods for estimating performance of cleaning agents. Two test methods were selected for evaluating performance: Environment Canada's Inclined Trough test and a Swirling Coupon test developed in the program.

  6. Electric vehicles performance estimation through a patterns extraction and classification methodology

    NASA Astrophysics Data System (ADS)

    Barré, Anthony; Suard, Frédéric; Gérard, Mathias; Riu, Delphine

    2015-01-01

    Direct estimation of battery performance is a major challenge as ageing process is a complex phenomenon not directly measurable. In this work a new methodology is provided to estimate global battery performances under real-life electric vehicle use. Such performances are estimated through battery signals patterns extraction. These signals patterns are used to identify physical degradation behavior of batteries. The analysis framework is composed of patterns extraction, clustering algorithms, summarizing data representation in the feature space of cluster distances and classification algorithms. This methodology is then applied on datasets, acquired from batteries used on electric vehicles, without controlled environmental conditions. The classification algorithm accuracy is studied on the obtained real data. The results suggest that battery signals patterns analysis provides an innovative technique for online estimation of the battery performance level. A detection of dysfunctions caused by ageing is also made, only based on battery signals pattern extracted during real vehicle accelerations.

  7. Preliminary Estimates of Loss of Juvenile Anadromous Salmonids to Predators in John Day Reservoir and Development of a Predation Model : Interim Report, 1986.

    SciTech Connect

    Rieman, Bruce E.

    1986-03-01

    We made preliminary estimates of the loss of juvenile salmonids to predation by walleye, Stizostedion v. vitreum, and northern squawfish, Ptychocheilus oregonensis, in John Day Reservoir in 1984 and 1985 using estimates of predator abundance and daily prey consumption rates. Preliminary estimates may be biased and may be adjusted as much as 30%, but indications are that predation could account for the majority of unexplained loss of juvenile salmonids in John Day Reservoir. Total loss was estimated at 4.1 million in 1984 and 3.3 million in 1985. Northern squawfish consumed 76% and 92% of these totals, respectively. The majority of loss occurred in mid reservoir areas, but loss in a small area, the boat-restricted zone immediately below McNary Dam, was disproportionately large. Peaks in loss in May and July corresponded with peaks in availability of salmonids. Estimated mortality from predation for April through June in 1984 and 1985 was 9% and 7% respectively, for chinook salmon, Oncorhynchus tshawytscha, and 10% and 15% for steelhead, Salmogairdneri. Mortality was variable with time but tended to increase over the period of migration. Mortality of chinook was estimated at 26% to 55% during July and August. A model of predation in John Day Reservoir is outlined. The model includes a predation submodel that can calculate loss from predator number and consumption rate; a population submodel that can relate predator abundance and population structure to recruitment, exploitation, natural mortality and growth; and a distribution submodel that can apportion predators among areas of the reservoir over time. Applications of the model are discussed for projecting expected changes in predation over time and identifying management alternatives that might limit the impact of predation.

  8. Preliminary report on the CTS transient event counter performance through the 1976 spring eclipse season

    NASA Technical Reports Server (NTRS)

    Stevens, N. J.; Lovell, R. R.; Klinect, V. W.

    1977-01-01

    The transient event counter is described, defining its operational characteristics, and presenting the preliminary results obtained through the first 90 days of operation including the Spring 1976 eclipse season. The results show that the CTS was charged to the point where discharges have occurred. The discharge induced transients have not caused any anomalous events in spacecraft operation. The data indicate that discharges can occur at any time during the day without preference to any local time quadrant. The number of discharges occurring in the 1 sec sample interval are greater than anticipated.

  9. Improving Estimation Performance in Networked Control Systems Applying the Send-on-delta Transmission Method

    PubMed Central

    Nguyen, Vinh Hao; Suh, Young Soo

    2007-01-01

    This paper is concerned with improving performance of a state estimation problem over a network in which a send-on-delta (SOD) transmission method is used. The SOD method requires that a sensor node transmit data to the estimator node only if its measurement value changes more than a given specified δ value. This method has been explored and applied by researchers because of its efficiency in the network bandwidth improvement. However, when this method is used, it is not ensured that the estimator node receives data from the sensor nodes regularly at every estimation period. Therefore, we propose a method to reduce estimation error in case of no sensor data reception. When the estimator node does not receive data from the sensor node, the sensor value is known to be in a (−δi,+δi) interval from the last transmitted sensor value. This implicit information has been used to improve estimation performance in previous studies. The main contribution of this paper is to propose an algorithm, where the sensor value interval is reduced to (−δi/2,+δi/2) in certain situations. Thus, the proposed algorithm improves the overall estimation performance without any changes in the send-on-delta algorithms of the sensor nodes. Through numerical simulations, we demonstrate the feasibility and the usefulness of the proposed method.

  10. Real-time Strehl and image quality performance estimator at Paranal Observatory

    NASA Astrophysics Data System (ADS)

    Mawet, Dimitri; Smette, Alain; Sarazin, Marc S.; Kuntschner, Harald; Girard, Julien H.

    2014-08-01

    Here we describe a prototype Strehl and image quality performance estimator and its integration into Paranal operations, starting with UT4 and its suite of three infrared instruments: adaptive optics-fed imager/spectrograph NACO (temporarily out of operations) and integral field unit SINFONI, as well as wide-field imager HAWK-I. The real-time estimator processes the ambient conditions (seeing, coherence time, airmass, etc.) from the DIMM, and telescope Shack-Hartmann image analyzer to produce estimates of image quality and Strehl ratio every ~ 30 seconds. The estimate is using ad-hoc instrumental models, based in part on the PAOLA adaptive optics simulator. We discuss the current performance of the estimator vs real IQ and Strehl measurements, its impact on service mode efficiency, prospects for full deployment at other UTs, its use for the adaptive optics facility (AOF), and inclusion of the SLODAR-measured fine turbulence characteristics.

  11. Preliminary Study of Relationships between Stability and Control Characteristics and Affordability for High-Performance Aircraft

    NASA Technical Reports Server (NTRS)

    Ogburn, Marilyn E.

    1998-01-01

    This paper describes a study that is being done as part of the Methods for Affordable Design (MAD) program within the National Aeronautics and Space Administration (NASA), for which the goal is to develop design methods and information that contribute to reductions in the aircraft development cycle time while increasing design confidence throughout the design cycle. The product of the study will be a database of information that relates key stability and control parameters to affordability considerations such as air combat exchange ratio, safety of flight, and probability of loss of the aircraft or pilot. The overall background and methodology are described, and preliminary results are shown for the first phase of the study to evaluate characteristics in the longitudinal axis. For these preliminary results a simplified analytical model of the aircraft response to uncommanded nose-up pitching moments was developed and used to characterize the requirements for recoveries to controlled flight conditions and to evaluate some parameters that affect the survivability of the aircraft and the pilot.

  12. Performance of a low-cost methane sensor for ambient concentration measurements in preliminary studies

    NASA Astrophysics Data System (ADS)

    Eugster, W.; Kling, G. W.

    2012-03-01

    Methane is the second most important greenhouse gas after CO2 and contributes to global warming. Its sources are not uniformly distributed across terrestrial and aquatic ecosystems, and most of the methane flux is expected to stem from hotspots which often occupy a very small fraction of the total landscape area. Continuous time-series measurements of CH4 concentrations can help identify and locate these methane hot-spots. Newer, low-cost trace gas sensors such as the Figaro TGS 2600 can detect CH4 even at ambient concentrations. Hence, in this paper we tested this sensor under real-world conditions over Toolik Lake, Alaska, to determine its suitability for preliminary studies before placing more expensive and service-intensive equipment at a given locality. A reasonably good agreement with parallel measurements made using a Los Gatos Research FMA 100 methane analyzer was found after removal of the strong cross-sensitivities for temperature and relative humidity. Correcting for this cross-sensitivity increased the absolute accuracy required for in-depth studies, and the reproducibility between two TGS 2600 sensors run in parallel is very good. We conclude that the relative CH4 concentrations derived from such sensors are sufficient for preliminary investigations in the search of potential methane hot-spots.

  13. Performance of a low-cost methane sensor for ambient concentration measurements in preliminary studies

    NASA Astrophysics Data System (ADS)

    Eugster, W.; Kling, G. W.

    2012-08-01

    Methane is the second most important greenhouse gas after CO2 and contributes to global warming. Its sources are not uniformly distributed across terrestrial and aquatic ecosystems, and most of the methane flux is expected to stem from hotspots which often occupy a very small fraction of the total landscape area. Continuous time-series measurements of CH4 concentrations can help identify and locate these methane hotspots. Newer, low-cost trace gas sensors such as the Figaro TGS 2600 can detect CH4 even at ambient concentrations. Hence, in this paper we tested this sensor under real-world conditions over Toolik Lake, Alaska, to determine its suitability for preliminary studies before placing more expensive and service-intensive equipment at a given locality. A reasonably good agreement with parallel measurements made using a Los Gatos Research FMA 100 methane analyzer was found after removal of the strong sensitivities for temperature and relative humidity. Correcting for this sensitivity increased the absolute accuracy required for in-depth studies, and the reproducibility between two TGS 2600 sensors run in parallel is very good. We conclude that the relative CH4 concentrations derived from such sensors are sufficient for preliminary investigations in the search of potential methane hotspots.

  14. Heavy oil recovery process: Conceptual engineering of a downhole methanator and preliminary estimate of facilities cost for application to North Slope Alaska

    SciTech Connect

    Not Available

    1990-01-01

    Results from Tasks 8 and 9 are presented. Task 8 addressed the cost of materials and manufacturing of the Downhole Methanator and the cost of drilling and completing the vertical cased well and two horizontal drain holes in the West Sak reservoir. Task 9 addressed the preliminary design of surface facilities to support the enhanced recovery of heavy oil. Auxiliary facilities include steam reformers for carbon dioxide-rich natural gas reforming, emergency electric generators, nitrogen gas generators, and an ammonia synthesis unit. The ammonia is needed to stabilize the swelling of clays in the reservoir. Cost estimations and a description of how they were obtained are given.

  15. Rocket experiments for spectral estimation of electron density fine structure in the auroral and equatorial ionosphere and preliminary results

    NASA Technical Reports Server (NTRS)

    Tomei, B. A.; Smith, L. G.

    1986-01-01

    Sounding rockets equipped to monitor electron density and its fine structure were launched into the auroral and equatorial ionosphere in 1980 and 1983, respectively. The measurement electronics are based on the Langmuir probe and are described in detail. An approach to the spectral analysis of the density irregularities is addressed and a software algorithm implementing the approach is given. Preliminary results of the analysis are presented.

  16. The Thermo Scientific HELIX-SFT noble gas mass spectrometer: (preliminary) performance for 40Ar/39Ar geochronology

    NASA Astrophysics Data System (ADS)

    Barfod, D. N.; Mark, D. F.; Morgan, L. E.; Tomkinson, T.; Stuart, F.; Imlach, J.; Hamilton, D.

    2011-12-01

    The Thermo Scientific HELIX-platform Split Flight Tube (HELIX-SFT) noble gas mass spectrometer is specifically designed for simultaneous collection of helium isotopes. The high mass spur houses a switchable 1011 - 1012 Ω resistor Faraday cup and the low mass spur a digital pulse-counting secondary electron multiplier (SEM). We have acquired the HELIX-SFT with the specific intention to measure argon isotopes for 40Ar/39Ar geochronology. This contribution will discuss preliminary performance (resolution, reproducibility, precision etc.) with respect to measuring argon isotope ratios for 40Ar/39Ar dating of geological materials. We anticipate the greatest impact for 40Ar/39Ar dating will be increased accuracy and precision, especially as we approach the techniques younger limit. Working with Thermo Scientific we have subtly modified the source, alpha and collector slits of the HELIX-SFT mass spectrometer to improve its resolution for resolving isobaric interferences at masses 36 to 40. The enhanced performance will allow for accurate and precise measurement of argon isotopes. Preliminary investigations show that we can obtain a valley resolution of >700 and >1300 (compared to standard HELIX-SFT specifications of >400 and >700) for the high and low mass spurs, respectively. The improvement allows for full resolution of hydrocarbons (C3+) at masses 37 - 40 and almost full resolution at mass 36. The HELIX-SFT will collect data in dual collection mode with 40Ar+ ion beams measured using the switchable 1011 - 1012 Ω resistor Faraday cup and 39Ar through 36Ar measured using the SEM. The HELIX-SFT requires Faraday-SEM inter-calibration but negates the necessity to inter-calibrate multiple electron multipliers. We will further present preliminary data from the dating of mineral standards: Alder Creek sanidine, Fish Canyon sanidine and Mount Dromedary biotite (GA1550).

  17. Preliminary Results of Nene II Engine Altitude-chamber Performance Investigation. 2; Altitude Performance using 18.41-inch Diameter-jet Nozzle

    NASA Technical Reports Server (NTRS)

    Armstron, J. C.; Wilsted, H. D.; Vincent, K. R.

    1948-01-01

    An investigation is being conducted to determine the altitude performance characteristics of the Nene II engine and its components. The present paper presents preliminary results obtained using a jet nozzle of 18.41 inches in diameter, giving an area equal to 96.4 percent of the area of the standard jet nozzle of this engine. The test results presented are for conditions simulating altitudes from seal level to 50,000 feet and ram-pressure ratios from 1.00 to 2.70. The ram pressure ratios correspond to flight Mach numbers between zero and 1.28.

  18. Emergency CT brain: preliminary interpretation with a tablet device: image quality and diagnostic performance of the Apple iPad.

    PubMed

    Mc Laughlin, Patrick; Neill, Siobhan O; Fanning, Noel; Mc Garrigle, Anne Marie; Connor, Owen J O; Wyse, Gerry; Maher, Michael M

    2012-04-01

    Tablet devices have recently been used in radiological image interpretation because they have a display resolution comparable to desktop LCD monitors. We identified a need to examine tablet display performance prior to their use in preliminary interpretation of radiological images. We compared the spatial and contrast resolution of a commercially available tablet display with a diagnostic grade 2 megapixel monochrome LCD using a contrast detail phantom. We also recorded reporting discrepancies, using the ACR RADPEER system, between preliminary interpretation of 100 emergency CT brain examinations on the tablet display and formal review on a diagnostic LCD. The iPad display performed inferiorly to the diagnostic monochrome display without the ability to zoom. When the software zoom function was enabled on the tablet device, comparable contrast detail phantom scores of 163 vs 165 points were achieved. No reporting discrepancies were encountered during the interpretation of 43 normal examinations and five cases of acute intracranial hemorrhage. There were seven RADPEER2 (understandable) misses when using the iPad display and 12 with the diagnostic LCD. Use of software zoom in the tablet device improved its contrast detail phantom score. The tablet allowed satisfactory identification of acute CT brain findings, but additional research will be required to examine the cause of "understandable" reporting discrepancies that occur when using tablet devices.

  19. Optimal Tuner Selection for Kalman Filter-Based Aircraft Engine Performance Estimation

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.; Garg, Sanjay

    2010-01-01

    A linear point design methodology for minimizing the error in on-line Kalman filter-based aircraft engine performance estimation applications is presented. This technique specifically addresses the underdetermined estimation problem, where there are more unknown parameters than available sensor measurements. A systematic approach is applied to produce a model tuning parameter vector of appropriate dimension to enable estimation by a Kalman filter, while minimizing the estimation error in the parameters of interest. Tuning parameter selection is performed using a multi-variable iterative search routine which seeks to minimize the theoretical mean-squared estimation error. This paper derives theoretical Kalman filter estimation error bias and variance values at steady-state operating conditions, and presents the tuner selection routine applied to minimize these values. Results from the application of the technique to an aircraft engine simulation are presented and compared to the conventional approach of tuner selection. Experimental simulation results are found to be in agreement with theoretical predictions. The new methodology is shown to yield a significant improvement in on-line engine performance estimation accuracy

  20. Preliminary report on the CTS transient event counter performance through the 1976 spring eclipse season

    NASA Technical Reports Server (NTRS)

    Stevens, N. J.; Levell, R. R.; Klinect, V. W.

    1976-01-01

    The transient event counter (TEC), senses and counts transients having a voltage rise of greater than five volts in three separate wire harnesses: the attitude control harness, the solar array instrumentation harness and the solar array power harness. The operational characteristics of TEC are defined and the preliminary results obtained through the first 90 days of operation including the spring 1976 eclipse season are presented. The results show that the Communications Technology Satellite was charged to the point where discharges occurred. The discharge induced transients did not cause any anomalous events in spacecraft operation. The data indicate that discharges can occur at any time during the day without preference to any local time quadrant. The number of discharges occurring in the one second sample interval are greater than anticipated. The compilation and review of the data is continuing.

  1. Performance of Small Bore 60NiTi Hybrid Ball Bearings: Preliminary Life Test Results

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Howard, S. Adam

    2016-01-01

    Small bore (R8 size) hybrid ball bearings made with 60NiTi races and silicon nitride balls are under development for highly corrosive aerospace applications that are also exposed to heavy static (shock) loads. The target application is the vacuum pump used inside the wastewater recycling system on the International Space Station. To verify bearing longevity, life tests are run at 2000rpm for time periods up to 5000 hours. Accelerometers with data tracking are used to monitor operation and the bearings are disassembled and inspected at intervals to assess wear. Preliminary tests show that bearings made from 60NiTi are feasible for this aerospace and potentially other industrial applications that must endure similar operating environments.

  2. Preliminary investigation of cooling-air ejector performance at pressure ratios from 1 to 10

    NASA Technical Reports Server (NTRS)

    Ellis, C W; Hollister, D P; Sargent, A F , Jr

    1951-01-01

    Preliminary investigation was made of conical cooling air ejector at primary pressure ratios from 1 to 10. The cooling-air flow was maintained at zero and the resulting pressure variation in the shroud indicated pumping ability. The cooling-air flow was maintained at zero and the resulting pressure variation in the shroud indicated pumping ability. The gross thrust of the ejector and nozzle were compared. Several ratios of the spacing between the nozzle and shroud exit to the nozzle exit diameter were investigated for several shroud to nozzle exit diameter ratios. Maximum gross thrust loss occurred under conditions of zero cooling-air flow and was as much as 35 percent below nozzle jet thrust. For minimum thrust loss, ejector should be designed with as low diameter and spacing ratio as possible.

  3. Beyond Neglect: Preliminary Evidence of Retrospective Time Estimation Abnormalities in Non-Neglect Stroke and Transient Ischemic Attack Patients

    PubMed Central

    Low, Essie; Crewther, Sheila G.; Perre, Diana L.; Ben Ong; Laycock, Robin; Tu, Hans; Wijeratne, Tissa

    2016-01-01

    Perception of the passage of time is essential for safe planning and navigation of everyday activities. Findings from the literature have demonstrated a gross underestimation of time interval in right-hemisphere damaged neglect patients, but not in non-neglect unilaterally-damaged patients, compared to controls. This study aimed to investigate retrospective estimation of the duration of a target detection task over two occasions, in 30 stroke patients (12 left-side stroke 15 right-side stroke, and 3 right-side stroke with neglect) and 10 transient ischemic attack patients, relative to 31 age-matched controls. Performances on visual short-term and working memory tasks were also examined to investigate the associations between timing abilities with residual cognitive functioning. Initial results revealed evidence of perceptual time underestimation, not just in neglect patients, but also in non-neglect unilaterally-damaged stroke patients and transient ischemic attack patients. Three months later, underestimation of time persisted only in left-side stroke and right-side stroke with neglect patients, who also demonstrated reduced short-term and working memory abilities. Findings from this study suggest a predictive role of residual cognitive impairments in determining the prognosis of perceptual timing abnormalities. PMID:26940859

  4. Peer influence on students' estimates of performance: social comparison in clinical rotations.

    PubMed

    Raat, A N Janet; Kuks, Jan B M; van Hell, E Ally; Cohen-Schotanus, Janke

    2013-02-01

    During clinical rotations, students move from one clinical situation to another. Questions exist about students' strategies for coping with these transitions. These strategies may include a process of social comparison because in this context it offers the student an opportunity to estimate his or her abilities to master a novel rotation. These estimates are relevant for learning and performance because they are related to self-efficacy. We investigated whether student estimates of their own future performance are influenced by the performance level and gender of the peer with whom the student compares him- or herself. We designed an experimental study in which participating students (n = 321) were divided into groups assigned to 12 different conditions. Each condition entailed a written comparison situation in which a peer student had completed the rotation the participant was required to undertake next. Differences between conditions were determined by the performance level (worse, similar or better) and gender of the comparison peer. The overall grade achieved by the comparison peer remained the same in all conditions. We asked participants to estimate their own future performance in that novel rotation. Differences between their estimates were analysed using analysis of variance (ANOVA). Students' estimates of their future performance were highest when the comparison peer was presented as performing less well and lowest when the comparison peer was presented as performing better (p < 0.001). Estimates of male and female students in same-gender comparison conditions did not differ. In two of three opposite-gender conditions, male students' estimates were higher than those of females (p < 0.001 and p < 0.05, respectively). Social comparison influences students' estimates of their future performance in a novel rotation. The effect depends on the performance level and gender of the comparison peer. This indicates that comparisons against particular peers may

  5. Time estimation as a secondary task to measure workload. [attention sharing effect on operator performance

    NASA Technical Reports Server (NTRS)

    Hart, S. G.

    1975-01-01

    Variation in the length of time productions and verbal estimates of duration was investigated to determine the influence of concurrent activity on operator time perception. The length of 10-, 20-, and 30-sec intervals produced while performing six different compensatory tracking tasks was significantly longer, 23% on the average, than those produced while performing no other task. Verbal estimates of session duration, taken at the end of each of 27 experimental sessions, reflected a parallel increase in subjective underestimation of the passage of time as the difficulty of the task performed increased. These data suggest that estimates of duration made while performing a manual control task provide stable and sensitive measures of the workload imposed by the primary task, with minimal interference.

  6. Time estimation as a secondary task to measure workload. [attention sharing effect on operator performance

    NASA Technical Reports Server (NTRS)

    Hart, S. G.

    1975-01-01

    Variation in the length of time productions and verbal estimates of duration was investigated to determine the influence of concurrent activity on operator time perception. The length of 10-, 20-, and 30-sec intervals produced while performing six different compensatory tracking tasks was significantly longer, 23% on the average, than those produced while performing no other task. Verbal estimates of session duration, taken at the end of each of 27 experimental sessions, reflected a parallel increase in subjective underestimation of the passage of time as the difficulty of the task performed increased. These data suggest that estimates of duration made while performing a manual control task provide stable and sensitive measures of the workload imposed by the primary task, with minimal interference.

  7. Preliminary Analysis of the CASES GPS Receiver Performance during Simulated Seismic Displacements

    NASA Astrophysics Data System (ADS)

    De la Rosa-Perkins, A.; Reynolds, A.; Crowley, G.; Azeem, I.

    2014-12-01

    We explore the ability of a new GPS software receiver, called CASES (Connected Autonomous Space Environment Sensor), to measure seismic displacements in realtime. Improvements in GPS technology over the last 20 years allow for precise measurement of ground motion during seismic events. For example, GPS data has been used to calculate displacement histories at an earthquake's epicenter and fault slip estimations with great accuracy. This is supported by the ability to measure displacements directly using GPS, bypassing the double integration that accelerometers require, and by higher clipping limits than seismometers. The CASES receiver developed by ASTRA in collaboration with Cornell University and the University of Texas, Austin represents a new geodetic-quality software-based GPS receiver that measures ionospheric space weather in addition to the usual navigation solution. To demonstrate, in a controlled environment, the ability of the CASES receiver to measure seismic displacements, we simulated ground motions similar to those generated during earthquakes, using a shake box instrumented with an accelerometer and a GPS antenna. The accelerometer measured the box's actual displacement. The box moved on a manually controlled axis that underwent varied one-dimensional motions (from mm to cm) at different frequencies and amplitudes. The CASES receiver was configured to optimize the accuracy of the position solution. We quantified the CASES GPS receiver performance by comparing the GPS solutions against the accelerometer data using various statistical analysis methods. The results of these tests will be presented. The CASES receiver is designed with multiple methods of accessing the data in realtime, ranging from internet connection, blue-tooth, cell-phone modem and Iridium modem. Because the CASES receiver measures ionospheric space weather in addition to the usual navigation solution, CASES provides not only the seimic signal, but also the ionospheric space weather

  8. Place-value understanding in number line estimation predicts future arithmetic performance.

    PubMed

    Dietrich, Julia F; Huber, Stefan; Dackermann, Tanja; Moeller, Korbinian; Fischer, Ursula

    2016-11-01

    In multi-digit numbers, the value of each digit is determined by its position within the digit string. Children's understanding of this place-value structure constitutes a building block for later arithmetic skills. We investigated whether a number line estimation task can provide an assessment of place-value understanding in first grade. We hypothesized that estimating the position of two-digit numbers requires place-value understanding. Therefore, we fitted a linear function to children's estimates of two-digit numbers and considered the resulting slope as a measure of children's place-value understanding. We observed a significant correlation between this slope and children's performance in a transcoding task known to require place-value understanding. Additionally, the slope for two-digit numbers assessed at the beginning of grade 1 predicted children's arithmetic performance at the end of grade 1. These results indicate that the number line estimation task may indeed constitute a valid measure for first-graders' place-value understanding. Moreover, these findings are hard to reconcile with the view that number line estimation directly assesses a spatial representation of numbers. Instead, our results suggest that numerical processes involved in performing the task (such as place-value understanding) may drive the association between number line estimation and arithmetic performance. © 2016 The British Psychological Society.

  9. Time estimation and performance on reproduction tasks in subtypes of children with attention deficit hyperactivity disorder.

    PubMed

    Bauermeister, Jose J; Barkley, Russell A; Martinez, Jose V; Cumba, Eduardo; Ramirez, Rafael R; Reina, Graciela; Matos, Maribel; Salas, Carmen C

    2005-03-01

    This study compared Hispanic children (ages 7 to 11) with combined type (CT, n=33) and inattentive type (IT, n=21) attention deficit hyperactivity disorder (ADHD) and a control group (n=25) on time-estimation and time-reproduction tasks. The ADHD groups showed larger errors in time reproduction but not in time estimation than the control group, and the groups did not differ from each other on their performance on this task. Individual differences could not be accounted for by oppositional-defiance ratings and low math or reading scores. Although various measures of executive functioning did not make significant unique contributions to time estimation performance, those of interference control and nonverbal working memory did so to the time-reproduction task. Findings suggest that ADHD is associated with a specific impairment in the capacity to reproduce rather than estimate time durations and that this may be related to the children's deficits in inhibition and working memory.

  10. Are estimates of meaningful decline in mobility performance consistent among clinically important subgroups? (Health ABC study).

    PubMed

    Perera, Subashan; Studenski, Stephanie; Newman, Anne; Simonsick, Eleanor; Harris, Tamara; Schwartz, Ann; Visser, Marjolein

    2014-10-01

    Meaningful change criteria help determine if function has improved or declined, but their magnitudes may vary across clinically relevant subgroups. We estimate meaningful decline in four common measures of physical performance in subgroups of older adults based on initial performance, demographics, chronic conditions, and health status. We used baseline (Year 1) and Year 4 data from the Health, Aging and Body Composition (Health ABC) study, a well-functioning cohort at baseline of white and black men and women (age 70-79), to evaluate the magnitude of meaningful decline in performance (6 m gait speed, 400-m walk time (400MWT), Short Physical Performance Battery, and Health ABC Physical Performance Battery (PPB), based on self-reported perceived mobility anchors (climbing 10 steps and walking ¼ mile). Estimates were stratified by initial performance, demographics, health status, chronic conditions, and body mass index, and compared across strata. For all four measures, small and substantial decline estimates were generally consistent among subgroups based on initial performance, demographics, health status, and chronic conditions. The only exception was for 400MWT, where men had greater estimates than women. For PPB, small change was 0.12 points, and substantial change was 0.22 points. Estimates of small and substantial meaningful decline resemble those previously reported for gait speed, 400MWT, and SPPB. Magnitudes of meaningful performance decline appear to be generally consistent across strata of initial performance, demographics, health status, body mass index, and chronic conditions. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. One-repetition maximum bench press performance estimated with a new accelerometer method.

    PubMed

    Rontu, Jari-Pekka; Hannula, Manne I; Leskinen, Sami; Linnamo, Vesa; Salmi, Jukka A

    2010-08-01

    The one repetition maximum (1RM) is an important method to measure muscular strength. The purpose of this study was to evaluate a new method to predict 1RM bench press performance from a submaximal lift. The developed method was evaluated by using different load levels (50, 60, 70, 80, and 90% of 1RM). The subjects were active floorball players (n = 22). The new method is based on the assumption that the estimation of 1RM can be calculated from the submaximal weight and the maximum acceleration of the submaximal weight during the lift. The submaximal bench press lift was recorded with a 3-axis accelerometer integrated to a wrist equipment and a data acquisition card. The maximum acceleration was calculated from the measurement data of the sensor and analyzed in personal computer with LabView-based software. The estimated 1RM results were compared with traditionally measured 1RM results of the subjects. An own estimation equation was developed for each load level, that is, 5 different estimation equations have been used based on the measured 1RM values of the subjects. The mean (+/-SD) of measured 1RM result was 69.86 (+/-15.72) kg. The mean of estimated 1RM values were 69.85-69.97 kg. The correlations between measured and estimated 1RM results were high (0.89-0.97; p < 0.001). The differences between the methods were very small (-0.11 to 0.01 kg) and were not significantly different from each other. The results of this study showed promising prediction accuracy for estimating bench press performance by performing just a single submaximal bench press lift. The estimation accuracy is competitive with other known estimation methods, at least with the current study population.

  12. Estimated effects of ionizing radiation upon military task performance: individual combat crewmember assessment

    SciTech Connect

    Anno, G.H.; Wilson, D.B.

    1984-04-01

    Quantitative estimates are developed of the performance levels for selected individual Army combat crewmembers exposed to prompt ionizing radiation from nuclear weapons. The performance levels, expressed in percent of normal (baseline) task performance, provide information for military operations planning, combat training, and computer simulation modeling of combat crew and unit effectiveness. The methodology is described where data from two separate bodies of information: acute radiation sickness symptomatology, and judgment of task performance time from Army combat crew questionnaires - are integrated to compute performance levels as a function of dose (free-in-air) and post-exposure time.

  13. Computer code for estimating installed performance of aircraft gas turbine engines. Volume 3: Library of maps

    NASA Technical Reports Server (NTRS)

    Kowalski, E. J.

    1979-01-01

    A computerized method which utilizes the engine performance data and estimates the installed performance of aircraft gas turbine engines is presented. This installation includes: engine weight and dimensions, inlet and nozzle internal performance and drag, inlet and nacelle weight, and nacelle drag. The use of two data base files to represent the engine and the inlet/nozzle/aftbody performance characteristics is discussed. The existing library of performance characteristics for inlets and nozzle/aftbodies and an example of the 1000 series of engine data tables is presented.

  14. Does neuropsychological performance impact on real-life functional achievements in obsessive-compulsive disorder? A preliminary study.

    PubMed

    Perna, Giampaolo; Cavedini, Paolo; Harvey, Philip D; Di Chiaro, Nunzia Valentina; Daccò, Silvia; Caldirola, Daniela

    2016-11-01

    We investigated the association between neuropsychological performance and real-life functioning in obsessive-compulsive disorder (OCD). As a secondary aim, we investigated the association between neuropsychological performance and self-reported quality of life (QoL). We retrospectively selected 68 of 240 inpatients with OCD, who had been hospitalised for a 4-week psychiatric rehabilitation programme. We used clinical information recorded in the patients' electronic medical records. We considered the following variables: neuropsychological performance (verbal/visual memory, sustained attention, visual-constructive ability, and language fluency; in a sub-sample of 37 subjects, divided attention, working memory, and attentional shifting were also available); real-life functional achievements (social/vocational outcomes and independent living); subjectively reported QoL (WHOQOL-BREF); obsessive-compulsive (OC) symptoms severity (DY-BOCS). We found significant associations between poorer neuropsychological performance and poorer achievements in independent living and vocational outcomes. Among the different neuropsychological tests, we found significant associations between language fluency/executive processing and independent living, and between divided attention, attentional shifting, working memory and vocational outcome. We found no significant associations between neuropsychological performance and subjectively reported QoL. OC symptoms severity was not associated with real-life functional achievements. Our preliminary results suggest that poorer neuropsychological performance may be associated with impaired real-life functioning in subjects with OCD.

  15. The performance of different propensity score methods for estimating marginal hazard ratios.

    PubMed

    Austin, Peter C

    2013-07-20

    Propensity score methods are increasingly being used to reduce or minimize the effects of confounding when estimating the effects of treatments, exposures, or interventions when using observational or non-randomized data. Under the assumption of no unmeasured confounders, previous research has shown that propensity score methods allow for unbiased estimation of linear treatment effects (e.g., differences in means or proportions). However, in biomedical research, time-to-event outcomes occur frequently. There is a paucity of research into the performance of different propensity score methods for estimating the effect of treatment on time-to-event outcomes. Furthermore, propensity score methods allow for the estimation of marginal or population-average treatment effects. We conducted an extensive series of Monte Carlo simulations to examine the performance of propensity score matching (1:1 greedy nearest-neighbor matching within propensity score calipers), stratification on the propensity score, inverse probability of treatment weighting (IPTW) using the propensity score, and covariate adjustment using the propensity score to estimate marginal hazard ratios. We found that both propensity score matching and IPTW using the propensity score allow for the estimation of marginal hazard ratios with minimal bias. Of these two approaches, IPTW using the propensity score resulted in estimates with lower mean squared error when estimating the effect of treatment in the treated. Stratification on the propensity score and covariate adjustment using the propensity score result in biased estimation of both marginal and conditional hazard ratios. Applied researchers are encouraged to use propensity score matching and IPTW using the propensity score when estimating the relative effect of treatment on time-to-event outcomes.

  16. The performance of different propensity score methods for estimating marginal hazard ratios

    PubMed Central

    Austin, Peter C

    2013-01-01

    Propensity score methods are increasingly being used to reduce or minimize the effects of confounding when estimating the effects of treatments, exposures, or interventions when using observational or non-randomized data. Under the assumption of no unmeasured confounders, previous research has shown that propensity score methods allow for unbiased estimation of linear treatment effects (e.g., differences in means or proportions). However, in biomedical research, time-to-event outcomes occur frequently. There is a paucity of research into the performance of different propensity score methods for estimating the effect of treatment on time-to-event outcomes. Furthermore, propensity score methods allow for the estimation of marginal or population-average treatment effects. We conducted an extensive series of Monte Carlo simulations to examine the performance of propensity score matching (1:1 greedy nearest-neighbor matching within propensity score calipers), stratification on the propensity score, inverse probability of treatment weighting (IPTW) using the propensity score, and covariate adjustment using the propensity score to estimate marginal hazard ratios. We found that both propensity score matching and IPTW using the propensity score allow for the estimation of marginal hazard ratios with minimal bias. Of these two approaches, IPTW using the propensity score resulted in estimates with lower mean squared error when estimating the effect of treatment in the treated. Stratification on the propensity score and covariate adjustment using the propensity score result in biased estimation of both marginal and conditional hazard ratios. Applied researchers are encouraged to use propensity score matching and IPTW using the propensity score when estimating the relative effect of treatment on time-to-event outcomes. Copyright © 2012 John Wiley & Sons, Ltd. PMID:23239115

  17. An Overdetermined System for Improved Autocorrelation Based Spectral Moment Estimator Performance

    NASA Technical Reports Server (NTRS)

    Keel, Byron M.

    1996-01-01

    Autocorrelation based spectral moment estimators are typically derived using the Fourier transform relationship between the power spectrum and the autocorrelation function along with using either an assumed form of the autocorrelation function, e.g., Gaussian, or a generic complex form and applying properties of the characteristic function. Passarelli has used a series expansion of the general complex autocorrelation function and has expressed the coefficients in terms of central moments of the power spectrum. A truncation of this series will produce a closed system of equations which can be solved for the central moments of interest. The autocorrelation function at various lags is estimated from samples of the random process under observation. These estimates themselves are random variables and exhibit a bias and variance that is a function of the number of samples used in the estimates and the operational signal-to-noise ratio. This contributes to a degradation in performance of the moment estimators. This dissertation investigates the use autocorrelation function estimates at higher order lags to reduce the bias and standard deviation in spectral moment estimates. In particular, Passarelli's series expansion is cast in terms of an overdetermined system to form a framework under which the application of additional autocorrelation function estimates at higher order lags can be defined and assessed. The solution of the overdetermined system is the least squares solution. Furthermore, an overdetermined system can be solved for any moment or moments of interest and is not tied to a particular form of the power spectrum or corresponding autocorrelation function. As an application of this approach, autocorrelation based variance estimators are defined by a truncation of Passarelli's series expansion and applied to simulated Doppler weather radar returns which are characterized by a Gaussian shaped power spectrum. The performance of the variance estimators determined

  18. Performance estimates for the Space Station power system Brayton Cycle compressor and turbine

    NASA Technical Reports Server (NTRS)

    Cummings, Robert L.

    1989-01-01

    The methods which have been used by the NASA Lewis Research Center for predicting Brayton Cycle compressor and turbine performance for different gases and flow rates are described. These methods were developed by NASA Lewis during the early days of Brayton cycle component development and they can now be applied to the task of predicting the performance of the Closed Brayton Cycle (CBC) Space Station Freedom power system. Computer programs are given for performing these calculations and data from previous NASA Lewis Brayton Compressor and Turbine tests is used to make accurate estimates of the compressor and turbine performance for the CBC power system. Results of these calculations are also given. In general, calculations confirm that the CBC Brayton Cycle contractor has made realistic compressor and turbine performance estimates.

  19. Estimating A Reference Standard Segmentation With Spatially Varying Performance Parameters: Local MAP STAPLE

    PubMed Central

    Commowick, Olivier; Akhondi-Asl, Alireza; Warfield, Simon K.

    2012-01-01

    We present a new algorithm, called local MAP STAPLE, to estimate from a set of multi-label segmentations both a reference standard segmentation and spatially varying performance parameters. It is based on a sliding window technique to estimate the segmentation and the segmentation performance parameters for each input segmentation. In order to allow for optimal fusion from the small amount of data in each local region, and to account for the possibility of labels not being observed in a local region of some (or all) input segmentations, we introduce prior probabilities for the local performance parameters through a new Maximum A Posteriori formulation of STAPLE. Further, we propose an expression to compute confidence intervals in the estimated local performance parameters. We carried out several experiments with local MAP STAPLE to characterize its performance and value for local segmentation evaluation. First, with simulated segmentations with known reference standard segmentation and spatially varying performance, we show that local MAP STAPLE performs better than both STAPLE and majority voting. Then we present evaluations with data sets from clinical applications. These experiments demonstrate that spatial adaptivity in segmentation performance is an important property to capture. We compared the local MAP STAPLE segmentations to STAPLE, and to previously published fusion techniques and demonstrate the superiority of local MAP STAPLE over other state-of-the- art algorithms. PMID:22562727

  20. Noninvasive measurement of aluminium in human bone: preliminary human study and improved system performance.

    PubMed

    Aslam; Davis, K; Pejović-Milić, A; Chettle, D R

    2009-11-01

    Aluminium has been measured in the hands of 18 referent subjects and six aluminium welders using the technique of in vivo neutron activation analysis. The minimal detection limit (MDL) in the human subjects was 28.0 microgAl/gCa, whereas it was 19.5 microgAl/gCa in calibration standards. On average the aluminium exposed subjects had higher levels of aluminium in their hands than did the referent subjects. However, this difference only just achieved significance at the 5% level and should be treated with caution, since the study had not been deliberately designed to assess this difference. Following the preliminary human study, improvements were made to the measurement system with respect to the gamma-ray detector array and to the timing sequence of irradiation-transfer-counting. These improvements were tested on the calibration standards, lowering the MDL from 19.5 microgAl/gCa to 8.32 microgAl/gCa. A similar improvement in human measurements would result in an in vivo MDL of 12.0 microgAl/gCa.

  1. Estimating time to contact during pursuit eye movements: Comparison between geometric model prediction and human performance

    NASA Astrophysics Data System (ADS)

    Matsumiya, Kazumichi; Kaneko, Hirohiko

    2008-07-01

    While an object is approaching a particular location, we can make an estimate of the time when the object will arrive at that location. A geometric model predicts that the estimate of time-to-contact (TTC) is greatly improved by using the rate of change of visual direction of the object when the object is moving with a slow velocity toward a point of nearest approach at a distance far from the observer. It has been shown that pursuit eye movements provide the rate of change of visual direction of an approaching object. We conducted psychophysical experiments, and compared TTC estimates during pursuit eye movements to those during fixation. We found that the differences in TTC estimates between fixation and pursuit show a qualitatively similar pattern to the geometric model prediction. However, the results also show that the magnitudes of the TTC estimation errors are greater than the theoretical values from the geometric model, indicating that the human visual system has a perceptual bias in estimating TTC. These results suggest that the human visual system estimates TTC during pursuit eye movements in a different way from the geometric model, although the effect of these eye movements on TTC estimates in human performance is qualitatively consistent with the model prediction.

  2. On the performance of Fisher Information Measure and Shannon entropy estimators

    NASA Astrophysics Data System (ADS)

    Telesca, Luciano; Lovallo, Michele

    2017-10-01

    The performance of two estimators of Fisher Information Measure (FIM) and Shannon entropy (SE), one based on the discretization of the FIM and SE formulae (discrete-based approach) and the other based on the kernel-based estimation of the probability density function (pdf) (kernel-based approach) is investigated. The two approaches are employed to estimate the FIM and SE of Gaussian processes (with different values of σ and size N), whose theoretic FIM and SE depend on the standard deviation σ. The FIM (SE) estimated by using the discrete-based approach is approximately constant with σ, but decreases (increases) with the bin number L; in particular, the discrete-based approach furnishes a rather correct estimation of FIM (SE) for L ∝ σ. Furthermore, for small values of σ, the larger the size N of the series, the smaller the mean relative error; while for large values of σ, the larger the size N of the series, the larger the mean relative error. The FIM (SE) estimated by using the kernel-based approach is very close to the theoretic value for any σ , and the mean relative error decreases with the increase of the length of the series. Comparing the results obtained using the discrete-based and kernel-based approaches, the estimates of FIM and SE by using the kernel-based approach are much closer to the theoretic values for any σ and any N and have to be preferred to the discrete-based estimates.

  3. Batch Effect Confounding Leads to Strong Bias in Performance Estimates Obtained by Cross-Validation

    PubMed Central

    Delorenzi, Mauro

    2014-01-01

    Background With the large amount of biological data that is currently publicly available, many investigators combine multiple data sets to increase the sample size and potentially also the power of their analyses. However, technical differences (“batch effects”) as well as differences in sample composition between the data sets may significantly affect the ability to draw generalizable conclusions from such studies. Focus The current study focuses on the construction of classifiers, and the use of cross-validation to estimate their performance. In particular, we investigate the impact of batch effects and differences in sample composition between batches on the accuracy of the classification performance estimate obtained via cross-validation. The focus on estimation bias is a main difference compared to previous studies, which have mostly focused on the predictive performance and how it relates to the presence of batch effects. Data We work on simulated data sets. To have realistic intensity distributions, we use real gene expression data as the basis for our simulation. Random samples from this expression matrix are selected and assigned to group 1 (e.g., ‘control’) or group 2 (e.g., ‘treated’). We introduce batch effects and select some features to be differentially expressed between the two groups. We consider several scenarios for our study, most importantly different levels of confounding between groups and batch effects. Methods We focus on well-known classifiers: logistic regression, Support Vector Machines (SVM), k-nearest neighbors (kNN) and Random Forests (RF). Feature selection is performed with the Wilcoxon test or the lasso. Parameter tuning and feature selection, as well as the estimation of the prediction performance of each classifier, is performed within a nested cross-validation scheme. The estimated classification performance is then compared to what is obtained when applying the classifier to independent data. PMID:24967636

  4. Batch effect confounding leads to strong bias in performance estimates obtained by cross-validation.

    PubMed

    Soneson, Charlotte; Gerster, Sarah; Delorenzi, Mauro

    2014-01-01

    With the large amount of biological data that is currently publicly available, many investigators combine multiple data sets to increase the sample size and potentially also the power of their analyses. However, technical differences ("batch effects") as well as differences in sample composition between the data sets may significantly affect the ability to draw generalizable conclusions from such studies. The current study focuses on the construction of classifiers, and the use of cross-validation to estimate their performance. In particular, we investigate the impact of batch effects and differences in sample composition between batches on the accuracy of the classification performance estimate obtained via cross-validation. The focus on estimation bias is a main difference compared to previous studies, which have mostly focused on the predictive performance and how it relates to the presence of batch effects. We work on simulated data sets. To have realistic intensity distributions, we use real gene expression data as the basis for our simulation. Random samples from this expression matrix are selected and assigned to group 1 (e.g., 'control') or group 2 (e.g., 'treated'). We introduce batch effects and select some features to be differentially expressed between the two groups. We consider several scenarios for our study, most importantly different levels of confounding between groups and batch effects. We focus on well-known classifiers: logistic regression, Support Vector Machines (SVM), k-nearest neighbors (kNN) and Random Forests (RF). Feature selection is performed with the Wilcoxon test or the lasso. Parameter tuning and feature selection, as well as the estimation of the prediction performance of each classifier, is performed within a nested cross-validation scheme. The estimated classification performance is then compared to what is obtained when applying the classifier to independent data.

  5. On the estimation algorithm used in adaptive performance optimization of turbofan engines

    NASA Technical Reports Server (NTRS)

    Espana, Martin D.; Gilyard, Glenn B.

    1993-01-01

    The performance seeking control algorithm is designed to continuously optimize the performance of propulsion systems. The performance seeking control algorithm uses a nominal model of the propulsion system and estimates, in flight, the engine deviation parameters characterizing the engine deviations with respect to nominal conditions. In practice, because of measurement biases and/or model uncertainties, the estimated engine deviation parameters may not reflect the engine's actual off-nominal condition. This factor has a necessary impact on the overall performance seeking control scheme exacerbated by the open-loop character of the algorithm. The effects produced by unknown measurement biases over the estimation algorithm are evaluated. This evaluation allows for identification of the most critical measurements for application of the performance seeking control algorithm to an F100 engine. An equivalence relation between the biases and engine deviation parameters stems from an observability study; therefore, it is undecided whether the estimated engine deviation parameters represent the actual engine deviation or whether they simply reflect the measurement biases. A new algorithm, based on the engine's (steady-state) optimization model, is proposed and tested with flight data. When compared with previous Kalman filter schemes, based on local engine dynamic models, the new algorithm is easier to design and tune and it reduces the computational burden of the onboard computer.

  6. The comparative performance of PMI estimation in skeletal remains by three methods (C-14, luminol test and OHI): analysis of 20 cases.

    PubMed

    Cappella, Annalisa; Gibelli, Daniele; Muccino, Enrico; Scarpulla, Valentina; Cerutti, Elisa; Caruso, Valentina; Sguazza, Emanuela; Mazzarelli, Debora; Cattaneo, Cristina

    2015-01-27

    When estimating post-mortem interval (PMI) in forensic anthropology, the only method able to give an unambiguous result is the analysis of C-14, although the procedure is expensive. Other methods, such as luminol tests and histological analysis, can be performed as preliminary investigations and may allow the operators to gain a preliminary indication concerning PMI, but they lack scientific verification, although luminol testing has been somewhat more accredited in the past few years. Such methods in fact may provide some help as they are inexpensive and can give a fast response, especially in the phase of preliminary investigations. In this study, 20 court cases of human skeletonized remains were dated by the C-14 method. For two cases, results were chronologically set after the 1950s; for one case, the analysis was not possible technically. The remaining 17 cases showed an archaeological or historical collocation. The same bone samples were also screened with histological examination and with the luminol test. Results showed that only four cases gave a positivity to luminol and a high Oxford Histology Index (OHI) score at the same time: among these, two cases were dated as recent by the radiocarbon analysis. Thus, only two false-positive results were given by the combination of these methods and no false negatives. Thus, the combination of two qualitative methods (luminol test and microscopic analysis) may represent a promising solution to cases where many fragments need to be quickly tested.

  7. Performance of an upper-ocean model coupled to an atmospheric GCM: preliminary results. Vol. 2

    SciTech Connect

    Pollard, D.

    1982-02-01

    A global dynamical model of the upper ocean and sea ice is coupled to the OSU atmospheric general circulation model. Preliminary results are described from a 16-month simulation with seasonally-varying insolation, and compared with both observations and the results from two earlier experiments with simpler upper-ocean models. The present ocean model consists of two vertically homogeneous layers of variable thickness: the upper layer represents the well-mixed layer and can entrain or detrain fluid locally with the lower layer, as in standard mixed-layer models. The second layer typically has thicknesses of approx.100 to approx.400 meters and crudely represents the seasonal thermocline and the part of the main thermocline involved in the subtropical gyres; it rests immiscibly on deep water of no motion where the density contrast is prescribed. Horizontal advection is predicted in both layers by the primitive momentum equations. Sea ice can form if the upper-layer temperature (SST) drops to freezing, after which the local ice thickness is predicted thermo-dynamically with ice dynamics neglected. The 16-month simulation is started from relatively realistic conditions obtained by spinning up the atmospheric and oceanic models separately. After several months of the coupled run, errors of up to 4/sup 0/C in the SST appear in the western oceans, probably due to the underestimate of the western boundary currents inherent in coarse-grid oceanic models. Equatorial upwelling and undercurrents are simulated but extend basin-wide, producing SSTs up to 6/sup 0/C too cold in the western equatorial Pacific. The large-scale seasonal variation of sea-ice thickness and extent are fairly realistic. Surface heat fluxes are compared with observations and with an earlier control integration of the atmospheric GCM, in an effort to distinguish between errors in the SST caused by the upper-ocean model and those caused by the atmospheric model. 38 refs., 11 figs.

  8. Competitive Performance Correlates of Mental Toughness in Tennis: A Preliminary Analysis.

    PubMed

    Cowden, Richard G

    2016-08-01

    This study investigated relationships between mental toughness and measures of competitive performance in tennis. Forty-three male (N = 25) and female (N = 18) players (M age = 13.6 years, SD = 2.4) completed the mental toughness inventory, and the point-by-point outcomes recorded during a competitive tennis match (singles) were used to generate performance indices for each athlete. The results indicated that mental toughness was associated with several, but not all, macro, micro, and critical moment performance indices. The findings suggest mental toughness may contribute to successful performance during tennis competition, although the importance of the construct appears to depend depend on specific match situations. Future mental toughness research should consider a range of factors related to sport performance, including athletes' and opponents' physical, technical, and tactical abilities. © The Author(s) 2016.

  9. Subject-specific estimation of central aortic blood pressure using an individualized transfer function: a preliminary feasibility study.

    PubMed

    Hahn, Jin-Oh; Reisner, Andrew T; Jaffer, Farouc A; Asada, H Harry

    2012-03-01

    This paper presents a new approach to the estimation of unknown central aortic blood pressure waveform from a directly measured peripheral blood pressure waveform, in which a physics-based model is employed to solve for a subject- and state-specific individualized transfer function (ITF). The ITF provides the means to estimate the unknown central aortic blood pressure from the peripheral blood pressure. Initial proof-of-principle for the ITF is demonstrated experimentally through an in vivo protocol. In swine subjects taken through wide range of physiologic conditions, the ITF was on average able to provide central aortic blood pressure waveforms more accurately than a nonindividualized transfer function. Its usefulness was most evident when the subject's pulse transit time deviated from normative values. In these circumstances, the ITF yielded statistically significant reductions over a nonindividualized transfer function in the following three parameters: 1) 30% reduction in the root-mean-squared error between estimated versus actual central aortic blood pressure waveform (p < 10 (-4)), 2) >50% reduction in the error between estimated versus actual systolic and pulse pressures ( p < 10 (-4)), and 3) a reduction in the overall breakdown rate (i.e., the frequency of estimation errors >3 mmHg, p < 10 (-4)). In conclusion, the ITF may offer an attractive alternative to existing methods that estimates the central aortic blood pressure waveform, and may be particularly useful in nonnormative physiologic conditions.

  10. Performance of Spanish/English bilingual children on a spanish-language neuropsychological battery: preliminary normative data.

    PubMed

    Rosselli, Mónica; Ardila, Alfredo; Navarrete, M Gina; Matute, Esmeralda

    2010-05-01

    Despite a population of close to 40 million Hispanics/Latinos in the USA who have at least some level of Spanish/English bilingualism, there are few neuropsychological tests and norms available for this group, especially when assessing Spanish/English bilingual children. The purpose of the present research was to provide preliminary normative data for a bilingual population on a comprehensive neuropsychological battery developed for Spanish-speaking children (Evaluación Neuropsicológica Infantil). Norms by age are presented on the performance of 108 Spanish/English bilingual children (ages 5-14 years) and are expected to be useful when testing other Spanish/English bilingual children in the USA.

  11. PRELIMINARY RESULTS OF EPA'S PERFORMANCE EVALUATION OF FEDERAL REFERENCE METHODS AND FEDERAL EQUIVALENT METHODS FOR COARSE PARTICULATE MATTER

    EPA Science Inventory

    The main objective of this study is to evaluate the performance of sampling methods for potential use as a Federal Reference Method (FRM) capable of providing an estimate of coarse particle (PMc: particulate matter with an aerodynamic diameter between 2.5 µm and 10 µm) ...

  12. LIFE ESTIMATION OF HIGH LEVEL WASTE TANK STEEL FOR F-TANK FARM CLOSURE PERFORMANCE ASSESSMENT

    SciTech Connect

    Subramanian, K

    2007-10-01

    High level radioactive waste (HLW) is stored in underground storage tanks at the Savannah River Site. The SRS is proceeding with closure of the 22 tanks located in F-Area. Closure consists of removing the bulk of the waste, chemical cleaning, heel removal, stabilizing remaining residuals with tailored grout formulations and severing/sealing external penetrations. A performance assessment is being performed in support of closure of the F-Tank Farm. Initially, the carbon steel construction materials of the high level waste tanks will provide a barrier to the leaching of radionuclides into the soil. However, the carbon steel liners will degrade over time, most likely due to corrosion, and no longer provide a barrier. The tank life estimation in support of the performance assessment has been completed. The estimation considered general and localized corrosion mechanisms of the tank steel exposed to the contamination zone, grouted, and soil conditions. The estimation was completed for Type I, Type III, and Type IV tanks in the F-Tank Farm. The tank life estimation in support of the F-Tank Farm closure performance assessment has been completed. The estimation considered general and localized corrosion mechanisms of the tank steel exposed to the contamination zone, grouted, and soil conditions. The estimation was completed for Type I, Type III, and Type IV tanks in the F-Tank Farm. Consumption of the tank steel encased in grouted conditions was determined to occur either due to carbonation of the concrete leading to low pH conditions, or the chloride-induced de-passivation of the steel leading to accelerated corrosion. A deterministic approach was initially followed to estimate the life of the tank liner in grouted conditions or in soil conditions. The results of this life estimation are shown in Table 1 and Table 2 for grouted and soil conditions respectively. The tank life has been estimated under conservative assumptions of diffusion rates. However, the same process of

  13. Performance anxiety at English PBL groups among Taiwanese medical students: a preliminary study.

    PubMed

    Chen, Cheng-Sheng; Lai, Chung-Sheng; Lu, Peih-Ying; Tsai, Jer-Chia; Chiang, Hung-Che; Huang, In-Ting; Yu, Hsin-Su

    2008-03-01

    Students' performance anxiety can impact negatively on the effectiveness of medical education reform, including performance in problem-based learning (PBL) and in using English in discussion. This study aimed to investigate the nature of performance anxiety among Taiwanese medical students in an English-language PBL group. Eighteen Taiwanese, one American and four Asian medical students who were attending an international PBL workshop were enrolled. A questionnaire seeking demographic data and experience in use of PBL and eight questions evaluating performance anxiety were administered. The performance anxiety of Taiwanese medical students was compared to that of the Asians and the one American. Frequencies of each performance anxiety were calculated. The results suggested that the Taiwanese students showed more anxiety than the one student from the United States, but less than other Asian students. The acts of giving a report, being the center of attention, and talking in the PBL group were the most common situations related to anxiety in PBL groups. Using English and working in a new PBL environment are possible sources of anxiety. The presence of anxiety among the Taiwanese medical students in English PBL groups implies the necessity for developing an effective strategy to deal with students' performance anxiety.

  14. Development and validation of trauma surgical skills metrics: Preliminary assessment of performance after training.

    PubMed

    Shackelford, Stacy; Garofalo, Evan; Shalin, Valerie; Pugh, Kristy; Chen, Hegang; Pasley, Jason; Sarani, Babak; Henry, Sharon; Bowyer, Mark; Mackenzie, Colin F

    2015-07-01

    Maintaining trauma-specific surgical skills is an ongoing challenge for surgical training programs. An objective assessment of surgical skills is needed. We hypothesized that a validated surgical performance assessment tool could detect differences following a training intervention. We developed surgical performance assessment metrics based on discussion with expert trauma surgeons, video review of 10 experts and 10 novice surgeons performing three vascular exposure procedures and lower extremity fasciotomy on cadavers, and validated the metrics with interrater reliability testing by five reviewers blinded to level of expertise and a consensus conference. We tested these performance metrics in 12 surgical residents (Year 3-7) before and 2 weeks after vascular exposure skills training in the Advanced Surgical Skills for Exposure in Trauma (ASSET) course. Performance was assessed in three areas as follows: knowledge (anatomic, management), procedure steps, and technical skills. Time to completion of procedures was recorded, and these metrics were combined into a single performance score, the Trauma Readiness Index (TRI). Wilcoxon matched-pairs signed-ranks test compared pretraining/posttraining effects. Mean time to complete procedures decreased by 4.3 minutes (from 13.4 minutes to 9.1 minutes). The performance component most improved by the 1-day skills training was procedure steps, completion of which increased by 21%. Technical skill scores improved by 12%. Overall knowledge improved by 3%, with 18% improvement in anatomic knowledge. TRI increased significantly from 50% to 64% with ASSET training. Interrater reliability of the surgical performance assessment metrics was validated with single intraclass correlation coefficient of 0.7 to 0.98. A trauma-relevant surgical performance assessment detected improvements in specific procedure steps and anatomic knowledge taught during a 1-day course, quantified by the TRI. ASSET training reduced time to complete vascular

  15. Performance validation of commercially available mobile waste-assay systems: Preliminary report

    SciTech Connect

    Schanfein, M.; Bonner, C.; Maez, R.

    1997-11-01

    Prior to disposal, nuclear waste must be accurately characterized to identify and quantify the radioactive content to reduce the radioactive hazard to the public. Validation of the waste-assay systems` performance is critical for establishing the credibility of the assay results for storage and disposal purposes. Canberra Nuclear has evaluated regulations worldwide and identified standard, modular, neutron- and gamma-waste-assay systems that can be used to characterize a large portion of existing and newly generated transuranic (TRU) and low-level waste. Before making claims of guaranteeing any system`s performance for specific waste types, the standardized systems` performance be evaluated. 7 figs., 11 tabs.

  16. Preliminary performance analysis of an interplanetary navigation system using asteroid based beacons

    NASA Technical Reports Server (NTRS)

    Jee, J. Rodney; Khatib, Ahmad R.; Muellerschoen, Ronald J.; Williams, Bobby G.; Vincent, Mark A.

    1988-01-01

    A futuristic interplanetary navigation system using transmitters placed on selected asteroids is introduced. This network of space beacons is seen as a needed alternative to the overly burdened Deep Space Network. Covariance analyses on the potential performance of these space beacons located on a candidate constellation of eight real asteroids are initiated. Simplified analytic calculations are performed to determine limiting accuracies attainable with the network for geometric positioning. More sophisticated computer simulations are also performed to determine potential accuracies using long arcs of range and Doppler data from the beacons. The results from these computations show promise for this navigation system.

  17. Preliminary performance of a vertical-attitude takeoff and landing, supersonic cruise aircraft concept having thrust vectoring integrated into the flight control system

    NASA Technical Reports Server (NTRS)

    Robins, A. W.; Beissner, F. L., Jr.; Domack, C. S.; Swanson, E. E.

    1985-01-01

    A performance study was made of a vertical attitude takeoff and landing (VATOL), supersonic cruise aircraft concept having thrust vectoring integrated into the flight control system. Those characteristics considered were aerodynamics, weight, balance, and performance. Preliminary results indicate that high levels of supersonic aerodynamic performance can be achieved. Further, with the assumption of an advanced (1985 technology readiness) low bypass ratio turbofan engine and advanced structures, excellent mission performance capability is indicated.

  18. Model-Based MR Parameter Mapping with Sparsity Constraints: Parameter Estimation and Performance Bounds

    PubMed Central

    Zhao, Bo; Lam, Fan; Liang, Zhi-Pei

    2014-01-01

    MR parameter mapping (e.g., T1 mapping, T2 mapping, T2∗ mapping) is a valuable tool for tissue characterization. However, its practical utility has been limited due to long data acquisition times. This paper addresses this problem with a new model-based parameter mapping method. The proposed method utilizes a formulation that integrates the explicit signal model with sparsity constraints on the model parameters, enabling direct estimation of the parameters of interest from highly undersampled, noisy k-space data. An efficient greedy-pursuit algorithm is described to solve the resulting constrained parameter estimation problem. Estimation-theoretic bounds are also derived to analyze the benefits of incorporating sparsity constraints and benchmark the performance of the proposed method. The theoretical properties and empirical performance of the proposed method are illustrated in a T2 mapping application example using computer simulations. PMID:24833520

  19. A complex symbol signal-to-noise ratio estimator and its performance

    NASA Technical Reports Server (NTRS)

    Feria, Y.

    1994-01-01

    This article presents an algorithm for estimating the signal-to-noise ratio (SNR) of signals that contain data on a downconverted suppressed carrier or the first harmonic of a square-wave subcarrier. This algorithm can be used to determine the performance of the full-spectrum combiner for the Galileo S-band (2.2- to 2.3-GHz) mission by measuring the input and output symbol SNR. A performance analysis of the algorithm shows that the estimator can estimate the complex symbol SNR using 10,000 symbols at a true symbol SNR of -5 dB with a mean of -4.9985 dB and a standard deviation of 0.2454 dB, and these analytical results are checked by simulations of 100 runs with a mean of -5.06 dB and a standard deviation of 0.2506 dB.

  20. Preliminary results from the evaluation of Cockpit Resource Management training - Performance ratings of flightcrews

    NASA Technical Reports Server (NTRS)

    Helmreich, Robert L.; Wilhelm, John A.; Gregorich, Steven E.; Chidester, Thomas R.

    1990-01-01

    The first data from the NASA/University of Texas Crew Performance project on the behavior of flightcrews with and without formal training in Cockpit Resource Management (CRM) is reported. Expert observers made detailed ratings of 15 components of crew behavior in both line operations and in full mission simulations. The results indicate that such training in crew coordination concepts increases the percentage of crews rated as above average in performance and decreases the percentage rated as below average. The data also show high and unexpected degrees of variations in rated performance among crews flying different aircraft within the same organization. It was also found that the specific behaviors that triggered observer ratings of above or below average performance differed markedly between organizations. Characteristics of experts' ratings and future research needs are also discussed.

  1. Preliminary Performance Evaluation of a Near Zero Energy Home in Callaway, Florida

    SciTech Connect

    Martin, Eric; Parker, Danny; Sherwin, John; Colon, Carlos

    2009-02-20

    This case study reports on a near zero energy home in Callaway, FL. This paper briefly reviews the design and then focuses on the first four months of energy performance during the second half of 2008.

  2. Preliminary results from the evaluation of Cockpit Resource Management training - Performance ratings of flightcrews

    NASA Technical Reports Server (NTRS)

    Helmreich, Robert L.; Wilhelm, John A.; Gregorich, Steven E.; Chidester, Thomas R.

    1990-01-01

    The first data from the NASA/University of Texas Crew Performance project on the behavior of flightcrews with and without formal training in Cockpit Resource Management (CRM) is reported. Expert observers made detailed ratings of 15 components of crew behavior in both line operations and in full mission simulations. The results indicate that such training in crew coordination concepts increases the percentage of crews rated as above average in performance and decreases the percentage rated as below average. The data also show high and unexpected degrees of variations in rated performance among crews flying different aircraft within the same organization. It was also found that the specific behaviors that triggered observer ratings of above or below average performance differed markedly between organizations. Characteristics of experts' ratings and future research needs are also discussed.

  3. A Preliminary Axial Fan Design Method with the Considerat ion of Performance and Noise Characteristics

    NASA Astrophysics Data System (ADS)

    Lee, Chan; Kil, Hyun Gwon

    2010-06-01

    Presented in this paper are a fan's aero-acoustic performance method and its computation procedure which combines aerodynamic flow field data, performances and noise levels of fan. The internal flow field and the performance of fan are analyzed by the through-flow modeling, inviscid pitch-averaged quasi-3D flow analysis combined with flow deviation and pressure loss distribution models. Based on the predicted internal flow field dada by the trough-flow modeling, fan noise is predicted by two models for the discrete frequency noise due to rotating steady aerodynamic thrust and blade interaction and for the broadband noise due to turbulent boundary layer and wake vortex shedding. The present predictions of the flow distribution, the performance and the noise level of fan are well agreed with actual test results.

  4. Preliminary Performance Analyses of the Constellation Program ARES 1 Crew Launch Vehicle

    NASA Technical Reports Server (NTRS)

    Phillips, Mark; Hanson, John; Shmitt, Terri; Dukemand, Greg; Hays, Jim; Hill, Ashley; Garcia, Jessica

    2007-01-01

    By the time NASA's Exploration Systems Architecture Study (ESAS) report had been released to the public in December 2005, engineers at NASA's Marshall Space Flight Center had already initiated the first of a series of detailed design analysis cycles (DACs) for the Constellation Program Crew Launch Vehicle (CLV), which has been given the name Ares I. As a major component of the Constellation Architecture, the CLV's initial role will be to deliver crew and cargo aboard the newly conceived Crew Exploration Vehicle (CEV) to a staging orbit for eventual rendezvous with the International Space Station (ISS). However, the long-term goal and design focus of the CLV will be to provide launch services for a crewed CEV in support of lunar exploration missions. Key to the success of the CLV design effort and an integral part of each DAC is a detailed performance analysis tailored to assess nominal and dispersed performance of the vehicle, to determine performance sensitivities, and to generate design-driving dispersed trajectories. Results of these analyses provide valuable design information to the program for the current design as well as provide feedback to engineers on how to adjust the current design in order to maintain program goals. This paper presents a condensed subset of the CLV performance analyses performed during the CLV DAC-1 cycle. Deterministic studies include development of the CLV DAC-1 reference trajectories, identification of vehicle stage impact footprints, an assessment of launch window impacts to payload performance, and the computation of select CLV payload partials. Dispersion studies include definition of input uncertainties, Monte Carlo analysis of trajectory performance parameters based on input dispersions, assessment of CLV flight performance reserve (FPR), assessment of orbital insertion accuracy, and an assessment of bending load indicators due to dispersions in vehicle angle of attack and side slip angle. A short discussion of the various

  5. Comparisons between Educator Performance Function-Based and Education Production Function-Based Teacher Effect Estimations

    ERIC Educational Resources Information Center

    Ham, Eun Hye

    2014-01-01

    Challenging the current discordance in orientation between student assessment models and teacher/school value-added models, this study aims to present the educator performance function (EPERF)-based teacher effect estimation method which utilizes the nature of student criterion-referenced assessment, to evaluate its feasibility and usefulness by…

  6. The Relative Performance of Full Information Maximum Likelihood Estimation for Missing Data in Structural Equation Models.

    ERIC Educational Resources Information Center

    Enders, Craig K.; Bandalos, Deborah L.

    2001-01-01

    Used Monte Carlo simulation to examine the performance of four missing data methods in structural equation models: (1)full information maximum likelihood (FIML); (2) listwise deletion; (3) pairwise deletion; and (4) similar response pattern imputation. Results show that FIML estimation is superior across all conditions of the design. (SLD)

  7. Estimating the Impact of Private Tutoring on Academic Performance: Primary Students in Sri Lanka

    ERIC Educational Resources Information Center

    Cole, Rachel

    2017-01-01

    Worldwide private tutoring is documented extensively, but its impact is unclear. I estimate the impact of tutoring on performance to assess the degree to which tutoring is a vehicle of educational stratification in Sri Lanka. I find that on average, five months of tutoring has no impact on Year 5 students' exam scores. I produce suggestive…

  8. Estimating the Impact of Private Tutoring on Academic Performance: Primary Students in Sri Lanka

    ERIC Educational Resources Information Center

    Cole, Rachel

    2017-01-01

    Worldwide private tutoring is documented extensively, but its impact is unclear. I estimate the impact of tutoring on performance to assess the degree to which tutoring is a vehicle of educational stratification in Sri Lanka. I find that on average, five months of tutoring has no impact on Year 5 students' exam scores. I produce suggestive…

  9. The Relative Performance of Full Information Maximum Likelihood Estimation for Missing Data in Structural Equation Models.

    ERIC Educational Resources Information Center

    Enders, Craig K.; Bandalos, Deborah L.

    2001-01-01

    Used Monte Carlo simulation to examine the performance of four missing data methods in structural equation models: (1)full information maximum likelihood (FIML); (2) listwise deletion; (3) pairwise deletion; and (4) similar response pattern imputation. Results show that FIML estimation is superior across all conditions of the design. (SLD)

  10. Performance of models for estimating absolute risk difference in multicenter trials with binary outcome.

    PubMed

    Pedroza, Claudia; Thanh Truong, Van Thi

    2016-08-30

    Reporting of absolute risk difference (RD) is recommended for clinical and epidemiological prospective studies. In analyses of multicenter studies, adjustment for center is necessary when randomization is stratified by center or when there is large variation in patients outcomes across centers. While regression methods are used to estimate RD adjusted for baseline predictors and clustering, no formal evaluation of their performance has been previously conducted. We performed a simulation study to evaluate 6 regression methods fitted under a generalized estimating equation framework: binomial identity, Poisson identity, Normal identity, log binomial, log Poisson, and logistic regression model. We compared the model estimates to unadjusted estimates. We varied the true response function (identity or log), number of subjects per center, true risk difference, control outcome rate, effect of baseline predictor, and intracenter correlation. We compared the models in terms of convergence, absolute bias and coverage of 95 % confidence intervals for RD. The 6 models performed very similar to each other for the majority of scenarios. However, the log binomial model did not converge for a large portion of the scenarios including a baseline predictor. In scenarios with outcome rate close to the parameter boundary, the binomial and Poisson identity models had the best performance, but differences from other models were negligible. The unadjusted method introduced little bias to the RD estimates, but its coverage was larger than the nominal value in some scenarios with an identity response. Under the log response, coverage from the unadjusted method was well below the nominal value (<80 %) for some scenarios. We recommend the use of a binomial or Poisson GEE model with identity link to estimate RD for correlated binary outcome data. If these models fail to run, then either a logistic regression, log Poisson regression, or linear regression GEE model can be used.

  11. Global Bare Ground Gain in the First Decade of 21st Century from Landsat Data: the Preliminary Results on Estimation and Distribution

    NASA Astrophysics Data System (ADS)

    Ying, Q.; Potapov, P.; Wang, L.; Hansen, M.

    2015-12-01

    Bare ground gain (BGG) is one of the most intensive land surface transformation because of the complete alteration of ecosystem functioning, the complex nature of temporal nonlinearity and spatial heterogeneity, the fast growing trend along with the global population boom and urbanization. However, it is not yet clear that what are the global dynamics of BGG and how it is spatially distributed. It is therefore important to monitor BGG as an essential component of land cover change on a locally relevant and globally consistent base. In this study, we try to answer these questions using over-a-decade Landsat satellite observations. Recent developments in optical remote sensing hold tremendous promise for global BGG detection. One data source is the legacy of annual Landsat mosaics from the research of Hansen et al. on global forest dynamics. Following previous research by Hansen et al., BGG observed by Landsat data is defined as a process of land cover change featuring permanent or semi-permanent clearing of vegetation cover by human land use or natural disturbances at the 30-m Landsat pixel scale. A sophisticated method has been developed to capture the change signal from high dimension metrics derived from time series of Landsat spectral bands and continuous bare ground field. By examining the contribution of each metric to the effectiveness of BGG detection, 140 metrics were selected and put into a supervised machine learning algorithm, the bagged classification tree. A recursive strategy was adopted to complete training data and improve result. A global BGG training data set counting to around 27.5 million pixels was produced. Additional training was obtained from regional sources like the bare ground gain layer of Web-enabled Landsat data (WELD) and the impervious surface layer of National Land Cover Database (NLCD). Independent validation was performed by interpreting stratified samples on Google Earth high resolution images. The preliminary results of the

  12. Heavy oil recovery process: Conceptual engineering of a downhole methanator and preliminary estimate of facilities cost for application to North Slope Alaska

    SciTech Connect

    Gondouin, M.

    1991-10-31

    The West Sak (Upper Cretaceous) sands, overlaying the Kuparuk field, would rank among the largest known oil fields in the US, but technical difficulties have so far prevented its commercial exploitation. Steam injection is the most successful and the most commonly-used method of heavy oil recovery, but its application to the West Sak presents major problems. Such difficulties may be overcome by using a novel approach, in which steam is generated downhole in a catalytic Methanator, from Syngas made at the surface from endothermic reactions (Table 1). The Methanator effluent, containing steam and soluble gases resulting from exothermic reactions (Table 1), is cyclically injected into the reservoir by means of a horizontal drainhole while hot produced fluids flow form a second drainhole into a central production tubing. The downhole reactor feed and BFW flow downward to two concentric tubings. The large-diameter casing required to house the downhole reactor assembly is filled above it with Arctic Pack mud, or crude oil, to further reduce heat leaks. A quantitative analysis of this production scheme for the West Sak required a preliminary engineering of the downhole and surface facilities and a tentative forecast of well production rates. The results, based on published information on the West Sak, have been used to estimate the cost of these facilities, per daily barrel of oil produced. A preliminary economic analysis and conclusions are presented together with an outline of future work. Economic and regulatory conditions which would make this approach viable are discussed. 28 figs.

  13. An appraisal of the 1992 preliminary performance assessment for the Waste Isolation Pilot Plant

    SciTech Connect

    Lee, W.W.L.; Chaturvedi, L.; Silva, M.K.; Weiner, R.; Neill, R.H. |

    1994-09-01

    The purpose of the New Mexico Environmental Evaluation Group is to conduct an independent technical evaluation of the Waste Isolation Pilot Plant (WIPP) Project to ensure the protection of the public health and safety and the environment. The WIPP Project, located in southeastern New Mexico, is being constructed as a repository for the disposal of transuranic (TRU) radioactive wastes generated by the national defense programs. The Environmental Evaluation Group (EEG) has reviewed the WIPP 1992 Performance Assessment (Sandia WIPP Performance Assessment Department, 1992). Although this performance assessment was released after the October 1992 passage of the WIPP Land Withdrawal Act (PL 102-579), the work preceded the Act. For individual and ground-water protection, calculations have been done for 1000 years post closure, whereas the US Environmental Protection Agency`s Standards (40 CFR 191) issued in 1993 require calculations for 10,000 years. The 1992 Performance Assessment continues to assimilate improved understanding of the geology and hydrogeology of the site, and evolving conceptual models of natural barriers. Progress has been made towards assessing WIPP`s compliance with the US Environmental Protection Agency`s Standards (40 CFR 191). The 1992 Performance Assessment has addressed several items of major concern to EEG, outlined in the July 1992 review of the 1991 performance assessment (Neill et al., 1992). In particular, the authors are pleased that some key results in this performance assessment deal with sensitivity of the calculated complementary cumulative distribution functions (CCDF) to alterative conceptual models proposed by EEG -- that flow in the Culebra be treated as single-porosity fracture-flow; with no sorption retardation unless substantiated by experimental data.

  14. Performance of creatinine-based estimates of GFR in kidney transplant recipients: a systematic review.

    PubMed

    White, Christine A; Huang, David; Akbari, Ayub; Garland, Jocelyn; Knoll, Greg A

    2008-06-01

    Glomerular filtration rate (GFR) commonly is estimated in kidney transplantation by using creatinine-based estimation equations. The performance of these equations in kidney transplant recipients is unclear, with conflicting results between studies. Systematic review. Stable adult kidney transplant recipients more than 6 months posttransplantation. Reporting of or ability to calculate from available data the GFR estimation equation bias (mean difference between measured GFR and estimated GFR) and percent accuracy (percentage of GFR estimates within 10%, 20%, or 30% of measured GFR). Creatinine-based GFR estimation equations (Cockcroft-Gault, 6-variable Modification of Diet in Renal Disease [MDRD] Study, 4-variable MDRD Study, and Nankivell). GFR determination using plasma or renal clearance of inulin, radioisotopes, or nonradiographic contrast. The search yielded 23 studies. For the 4-variable MDRD Study equation, bias ranged from -11.4 to +9.2 mL/min/1.73 m(2) (0.15 mL/s/1.73 m(2)). Only 76% of estimates were within 30% of measured GFR. For the Cockcroft-Gault equation, bias ranged from -4.0 to +16 mL/min/1.73 m(2) and 73% of estimates were within 30% of measured GFR. For the Nankivell equation, bias ranged from -1.4 mL/min to 36.3 mL/min with a 30% accuracy of only 68%. This review is limited by the inability to pool bias data, lack of calibration of serum creatinine in the majority of studies, and inclusion of nonindependent observations in many studies. Differences in patient populations, baseline GFRs of the study group, reference standard GFR used, and creatinine assay calibration likely account for the heterogeneity in results. These factors need to be considered by investigators and clinicians when interpreting estimates of GFR in kidney transplant recipients.

  15. LIFE ESTIMATION OF TRANSFER LINES FOR TANK FARM CLOSURE PERFORMANCE ASSESSMENT

    SciTech Connect

    Subramanian, K

    2007-10-01

    A performance assessment is being performed in support of closure of the F-Tank Farm. The performance assessment includes the life estimation of the transfer lines that are used to transport waste between tanks both within a facility (''intra-area'' transfer) and to other facilities (''inter-area'' transfers). The transfer line materials of construction will initially provide a barrier to contaminant escape. However, the materials will degrade over time, most likely due to corrosion, and will no longer provide a barrier to contaminant escape. The life estimation considered the corrosion of the core pipe under exposure to soil, estimated the thickness loss due to general corrosion, and the percentage of wall area breached due to localized corrosion mechanisms. There are three types of transfer lines that are to be addressed within the performance assessment: Type I, Type II/IIA and Type III. The life of the transfer lines were estimated as exposed to soil. Localized and general corrosion of the transfer lines exposed to soil was estimated to provide input to the fate and transport modeling of the performance assessment. Pitting corrosion was found to be the controlling mechanism for the degradation of the transfer lines and their consequent ability to maintain confinement of contaminants. It is assumed that 75% of the transfer line is needed intact to provide this confinement function, i.e. once 25% of the line wall is breached, the lines are considered incapable of confining contaminants. It is recommended that the percentage breached curves be utilized for each transfer line as shown in Figure 1 for the various stainless steel transfer lines.

  16. Design and performance estimation of a 35 T 40 mm no-insulation all-REBCO user magnet

    NASA Astrophysics Data System (ADS)

    Kim, Kwangmin; Bhattarai, Kabindra R.; Jang, Jae Young; Hwang, Young Jin; Kim, Kwanglok; Yoon, Sangwon; Lee, SangGap; Hahn, Seungyong

    2017-06-01

    This paper presents a design of a 35 T 40 mm winding diameter no-insulation standalone magnet that consists of a stack of 52 double pancake (DP) coils wound with multi-width REBCO tapes. The inner and outer diameters and height of the magnet are 40 mm, 221.6 mm, and 628 mm, respectively. It is designed to generate 35 T at an operating current (I op) of 179.8 A in a bath of liquid helium at 4.2 K. All the DP coils will be ‘dry’ wound without epoxy, making turns within the DP coils to be essentially ‘self-supporting,’ which is effective to reduce the magnetic stress. To reduce the magnet charging time constant, the so-called ‘metallic cladding’ REBCO tapes will be adopted, where a 1-2 μm thick stainless steel layer surrounds the tapes hermetically. With an average surface contact resistance (R ct) of 170 μ {{Ω }} cm-2, experimentally obtained from a charging test of our recent 3 T 100 mm stainless steel cladding REBCO magnet, the charging time constant of the 35 T magnet was estimated to be 3.01 minutes, though the magnet will be energized substantially slower over a few hours to reduce ac loss and Joule heating from radial turn-to-turn leak currents. A preliminary post-quench analysis, based on our lumped equivalent circuit model, was performed; the total stored energy of 1.79 MJ (magnet inductance: 110.5 H) was expected to be discharged in approximately 1.28 seconds after a quench due to the fast electromagnetic quench propagation among the DP coils, while the peak hot spot temperature was estimated to rise to 94 K, acceptable for a safe quench of a REBCO magnet.

  17. Compressive Strength Estimation of Marble Specimens using Acoustic Emission Hits in Time and Natural Time Domains: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Hloupis, George; Stavrakas, Ilias; Vallianatos, Filippos; Triantis, Dimos

    2013-04-01

    The current study deals with preliminary results of characteristic patterns derived from acoustic emissions during compressional stress. Two loading cycles were applied to a specimen of 4cm x 4cm x 10 cm Dionysos marble while acoustic emissions (AE) were recorded using one acoustic sensor coupled at the expected direction of the main crack (at the center of the specimen). The produced time series comprised from the number of counts per AE hit under increasing and constant load. Processing took place in two domains: in conventional time domain (t), using multiresolution wavelet analysis for the study of temporal variation of the wavelet-coefficients' standard deviation (SDEV) [1] and in natural time domain (χ), using the variance (κ1) of natural-time transformed time-series [2,3]. Results in both cases, dictate that identification of the region where the increasing stress (σ), exceeds 40% of the ultimate compressional strength (σ*), is possible. More specific, in conventional time domain, the temporal evolution of SDEV presents a sharp change around σ* during first loading cycle and less than σ* during second loading cycle. In natural time domain, the κ1 value clearly oscillate around 0.07 at natural time indexes corresponding to σ* during first loading cycle. Merging both results leads to a preliminary observation that we have an identification of the time when the compressional stress exceeds σ*. References [1] Telesca, L., Hloupis, G., Nikolintaga, I., Vallianatos, F.,."Temporal patterns in southern Aegean seismicity revealed by the multiresolution wavelet analysis", Communications in Nonlinear Science and Numerical Simulation, vol. 12, issue 8, pp 1418-1426, 2007 [2] P. A. Varotsos, N. V. Sarlis, and E. S. Skordas, "Natural Time Analysis: The New View of Time. Precursory Seismic Electric Signals, Earthquakes and other Complex Time-Series", Springer-Verlag, Berlin, Heidelberg, 2011. [3] N. V. Sarlis, P. A. Varotsos, and E. S. Skordas, "Flux Avalances in

  18. A preliminary study of the effect of eliminating requirements on clinical performance.

    PubMed

    Dodge, W W; Dale, R A; Hendricson, W D

    1993-09-01

    This study determined the effect of a clinical program driven by patient needs upon students' productivity, attitudes, and academic performance. A group of eight senior students, whose academic and clinical performance profile replicated that of the rest of the class, were chosen to participate in a year-long non-requirement clinic. The students were expected to attend all clinic sessions, and treat their assigned patients. Their performance was compared to that of classmates in the regular requirement-driven curriculum. The non-requirement group had significantly higher academic achievement and significantly outproduced their classmates. Non-requirement students had no state board failures, versus 17 percent in the regular curriculum, and reported significantly lower stress. This study suggests that predoctoral clinical programs can maintain quality and productivity in the absence of unit requirements.

  19. Preliminary analytical results using surface current integration for predicting effects of surface pillows on RF performance

    NASA Technical Reports Server (NTRS)

    Farrell, C. E.; Strange, D. A.

    1982-01-01

    An overview of the fast integral RF evaluation (FIRE) program is presented. This program uses surface current integration to evaluate RF performance of antenna systems. It requires modeling of surfaces in X, Y, Z coordinates along equally spaced X and Y grids with Z in the focal directon. The far field contribution of each surface point includes the effects of the Z-component of surface current which is not included in the aperture integration technique. Because of this, surface current integration is the most effective and inclusive technique for predicting RF performance on non-ideal reflectors. Results obtained from use of the FIRE program and an aperture integration program to predict RF performance of a LSS antenna concept are presented.

  20. Preliminary Performance of Lithium-ion Cell Designs for Ares I Upper Stage Applications

    NASA Technical Reports Server (NTRS)

    Miller, Thomas B.; Reid, Concha M.; Kussmaul, Michael T.

    2011-01-01

    NASA's Ares I Crew Launch Vehicle (CLV) baselined lithium-ion technology for the Upper Stage (US). Under this effort, the NASA Glenn Research Center investigated three different aerospace lithium-ion cell suppliers to assess the performance of the various lithium-ion cell designs under acceptance and characterization testing. This paper describes the overall testing approaches associated with lithium-ion cells, their ampere-hour capacity as a function of temperature and discharge rates, as well as their performance limitations for use on the Ares I US vehicle.

  1. Performance of the modified Poisson regression approach for estimating relative risks from clustered prospective data.

    PubMed

    Yelland, Lisa N; Salter, Amy B; Ryan, Philip

    2011-10-15

    Modified Poisson regression, which combines a log Poisson regression model with robust variance estimation, is a useful alternative to log binomial regression for estimating relative risks. Previous studies have shown both analytically and by simulation that modified Poisson regression is appropriate for independent prospective data. This method is often applied to clustered prospective data, despite a lack of evidence to support its use in this setting. The purpose of this article is to evaluate the performance of the modified Poisson regression approach for estimating relative risks from clustered prospective data, by using generalized estimating equations to account for clustering. A simulation study is conducted to compare log binomial regression and modified Poisson regression for analyzing clustered data from intervention and observational studies. Both methods generally perform well in terms of bias, type I error, and coverage. Unlike log binomial regression, modified Poisson regression is not prone to convergence problems. The methods are contrasted by using example data sets from 2 large studies. The results presented in this article support the use of modified Poisson regression as an alternative to log binomial regression for analyzing clustered prospective data when clustering is taken into account by using generalized estimating equations.

  2. Sensor biases effect on the estimation algorithm for performance-seeking controllers

    NASA Technical Reports Server (NTRS)

    Espana, Martin D.

    1994-01-01

    The performance-seeking-control algorithm (PSC) is designed to continuously optimize the performance of propulsion systems. The PSC uses a nominal model of the propulsion system and estimates, in flight, the engine deviation parameters (EDPs) characterizing engine deviations with respect to nominal conditions. In practice, the measurement biases (or model uncertainties) may prevent the estimated EDPs from reflecting the engine's actual off-nominal condition. This factor has a direct impact on the PSC scheme exacerbated by the open-loop character of the algorithm. An observability analysis shows that the biases cannot be estimated together with the EDPs. Moreover, biases and EDPs turn out to have equivalent effects on the measurements, leaving it undecided whether the estimated EDPs represent the actual engine deviation or whether they simply reflect the measurement biases. In this article, the effects produced by unknown measurement biases over the estimation algorithm are evaluated. This evaluation allows for identification of the most critical measurements for application of the PSC algorithm to an F100 engine.

  3. Performances estimation of a rotary traveling wave ultrasonic motor based on two-dimension analytical model.

    PubMed

    Ming, Y; Peiwen, Q

    2001-03-01

    The understanding of ultrasonic motor performances as a function of input parameters, such as the voltage amplitude, driving frequency, the preload on the rotor, is a key to many applications and control of ultrasonic motor. This paper presents performances estimation of the piezoelectric rotary traveling wave ultrasonic motor as a function of input voltage amplitude and driving frequency and preload. The Love equation is used to derive the traveling wave amplitude on the stator surface. With the contact model of the distributed spring-rigid body between the stator and rotor, a two-dimension analytical model of the rotary traveling wave ultrasonic motor is constructed. Then the performances of stead rotation speed and stall torque are deduced. With MATLAB computational language and iteration algorithm, we estimate the performances of rotation speed and stall torque versus input parameters respectively. The same experiments are completed with the optoelectronic tachometer and stand weight. Both estimation and experiment results reveal the pattern of performance variation as a function of its input parameters.

  4. Emergency Department Trends from the Drug Abuse Warning Network, Preliminary Estimates January-June 2002. Drug Abuse Warning Network Series.

    ERIC Educational Resources Information Center

    Substance Abuse and Mental Health Services Administration (DHHS/PHS), Rockville, MD. Office of Applied Studies.

    This publication presents estimates of drug-related emergency department (ED) episodes from the Drug Abuse Warning Network (DAWN) from 1994 through the first half of 2001. DAWN is an ongoing, national data system that collects information on drug-related visits to EDs from a national probability sample of hospitals. This publication marks a major…

  5. Preliminary Findings of Serum Creatinine and Estimated Glomerular Filtration Rate (eGFR) in Adolescents with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Lin, Jin-Ding; Lin, Lan-Ping; Hsieh, Molly; Lin, Pei-Ying

    2010-01-01

    The present study aimed to describe the kidney function profile--serum creatinine and estimated glomerular filtration rate (eGFR), and to examine the relationships of predisposing factors to abnormal serum creatinine in people with intellectual disabilities (ID). Data were collected by a cross-sectional study of 827 aged 15-18 years adolescents…

  6. Global Admittance Estimates of Elastic and Crustal Thickness of Venus: Preliminary Results from Top and Bottom Loading Models

    NASA Technical Reports Server (NTRS)

    Anderson, F. S.; Smrekar, S. E.

    2001-01-01

    Initial elastic and crustal thickness estimates (Te and Zc) for a global set of local admittance inversions with a one degree spacing for Venus provide a global map for interpreting subsurface structure. Additional information is contained in the original extended abstract.

  7. Preliminary Findings of Serum Creatinine and Estimated Glomerular Filtration Rate (eGFR) in Adolescents with Intellectual Disabilities

    ERIC Educational Resources Information Center

    Lin, Jin-Ding; Lin, Lan-Ping; Hsieh, Molly; Lin, Pei-Ying

    2010-01-01

    The present study aimed to describe the kidney function profile--serum creatinine and estimated glomerular filtration rate (eGFR), and to examine the relationships of predisposing factors to abnormal serum creatinine in people with intellectual disabilities (ID). Data were collected by a cross-sectional study of 827 aged 15-18 years adolescents…

  8. Dual Arm Work Package performance estimates and telerobot task network simulation

    SciTech Connect

    Draper, J.V.; Blair, L.M.

    1997-02-01

    This paper describes the methodology and results of a network simulation study of the Dual Arm Work Package (DAWP), to be employed for dismantling the Argonne National Laboratory CP-5 reactor. The development of the simulation model was based upon the results of a task analysis for the same system. This study was performed by the Oak Ridge National Laboratory (ORNL), in the Robotics and Process Systems Division. Funding was provided the US Department of Energy`s Office of Technology Development, Robotics Technology Development Program (RTDP). The RTDP is developing methods of computer simulation to estimate telerobotic system performance. Data were collected to provide point estimates to be used in a task network simulation model. Three skilled operators performed six repetitions of a pipe cutting task representative of typical teleoperation cutting operations.

  9. Improving International-Level Chess Players' Performance with an Acceptance-Based Protocol: Preliminary Findings

    ERIC Educational Resources Information Center

    Ruiz, Francisco J.; Luciano, Carmen

    2012-01-01

    This study compared an individual, 4-hr intervention based on acceptance and commitment therapy (ACT) versus a no-contact control condition in improving the performance of international-level chess players. Five participants received the brief ACT protocol, with each matched to another chess player with similar characteristics in the control…

  10. A Preliminary Study of the Effect of Eliminating Requirements on Clinical Performance.

    ERIC Educational Resources Information Center

    Dodge, William W.; And Others

    1993-01-01

    A study compared the performance of dental students following the traditional clinical curriculum that requires exposure to a specific range of discipline-oriented procedures with that of eight similar students in a curriculum focused on meeting patient needs but not traditional curriculum-based requirements. The nonrequirement group had higher…

  11. Learning Strategies and Self-Efficacy as Predictors of Academic Performance: A Preliminary Study

    ERIC Educational Resources Information Center

    Yip, Michael C. W.

    2012-01-01

    Empirical research supports the idea that differences in academic performance among students are largely due to their different learning and study strategies. The strategies, in turn, affect the self-efficacy of the students. Two hundred university students were recruited to participate in this study by completing a revised Chinese version of the…

  12. Timed activity performance in persons with upper limb amputation: A preliminary study.

    PubMed

    Resnik, Linda; Borgia, Mathew; Acluche, Frantzy

    2017-05-06

    55 subjects with upper limb amputation were administered the T-MAP twice within one week. To develop a timed measure of activity performance for persons with upper limb amputation (T-MAP); examine the measure's internal consistency, test-retest reliability and validity; and compare scores by prosthesis use. Measures of activity performance for persons with upper limb amputation are needed The time required to perform daily activities is a meaningful metric that implication for participation in life roles. Internal consistency and test-retest reliability were evaluated. Construct validity was examined by comparing scores by amputation level. Exploratory analyses compared sub-group scores, and examined correlations with other measures. Scale alpha was 0.77, ICC was 0.93. Timed scores differed by amputation level. Subjects using a prosthesis took longer to perform all tasks. T-MAP was not correlated with other measures of dexterity or activity, but was correlated with pain for non-prosthesis users. The timed scale had adequate internal consistency and excellent test-retest reliability. Analyses support reliability and construct validity of the T-MAP. 2c "outcomes" research. Published by Elsevier Inc.

  13. Effectiveness and Achievement: A Preliminary Comparison of Computer Assisted and Print Drill Performance Levels.

    ERIC Educational Resources Information Center

    Campbell, Donald L.; And Others

    The performance of two groups of 24 third-grade students practicing division problems was used to assess the effect of microcomputer drill programs on learning. An experimental group that used computer drill programs from the Milliken Math Sequences package was compared with a similar group that learned division using the traditional print drill…

  14. Nursing Student Performance, 1986-1993: Preliminary Findings. Program Evaluation PE93-1.

    ERIC Educational Resources Information Center

    Boughan, Karl

    A study was conducted at Prince George's Community College (PGCC), in Maryland, to evaluate nursing student performance from point of admission to the taking of the National Council Licensure Examination (NCLEX). A sample of 853 students who enrolled in the nursing program entry course between fall 1986 and spring 1992 were surveyed to determine…

  15. Improving International-Level Chess Players' Performance with an Acceptance-Based Protocol: Preliminary Findings

    ERIC Educational Resources Information Center

    Ruiz, Francisco J.; Luciano, Carmen

    2012-01-01

    This study compared an individual, 4-hr intervention based on acceptance and commitment therapy (ACT) versus a no-contact control condition in improving the performance of international-level chess players. Five participants received the brief ACT protocol, with each matched to another chess player with similar characteristics in the control…

  16. Relationships between handwriting performance and organizational abilities among children with and without dysgraphia: a preliminary study.

    PubMed

    Rosenblum, Sara; Aloni, Tsipi; Josman, Naomi

    2010-01-01

    Organizational ability constitutes one executive function (EF) component essential for common everyday performance. The study aim was to explore the relationship between handwriting performance and organizational ability in school-aged children. Participants were 58 males, aged 7-8 years, 30 with dysgraphia and 28 with proficient handwriting. Group allocation was based on children's scores in the Handwriting Proficiency Screening Questionnaire (HPSQ). They performed the Hebrew Handwriting Evaluation (HHE), and their parents completed the Questionnaire for Assessing Students' Organizational Abilities-for Parents (QASOA-P). Significant differences were found between the groups for handwriting performance (HHE) and organizational abilities (QASOA-P). Significant correlations were found in the dysgraphic group between handwriting spatial arrangement and the QASOA-P mean score. Linear regression indicated that the QASOA-P mean score explained 42% of variance of handwriting proficiency (HPSQ). Based on one discriminant function, 81% of all participants were correctly classified into groups. Study results strongly recommend assessing organizational difficulties in children referred for therapy due to handwriting deficiency.

  17. A Preliminary Study of the Effect of Eliminating Requirements on Clinical Performance.

    ERIC Educational Resources Information Center

    Dodge, William W.; And Others

    1993-01-01

    A study compared the performance of dental students following the traditional clinical curriculum that requires exposure to a specific range of discipline-oriented procedures with that of eight similar students in a curriculum focused on meeting patient needs but not traditional curriculum-based requirements. The nonrequirement group had higher…

  18. Urgency, Responsibility, Efficacy: Preliminary Findings of a Study of High-Performing Texas School Districts.

    ERIC Educational Resources Information Center

    Ragland, Mary A.; Asera, Rose; Johnson, Joseph F., Jr.

    An on-going study of the performance of high-poverty schools in Texas is revealing entire school districts where such schools are achieving high academic results. Instead of isolated pockets of excellence, a few large and medium-sized districts have been identified in which a cluster of high-poverty schools is achieving at the top levels of the…

  19. A Preliminary Investigation of the Effect of Rules on Employee Performance

    ERIC Educational Resources Information Center

    Squires, James; Wilder, David A.

    2010-01-01

    The way in which rules impact workplace performance has been a topic of discussion in the Organizational Behavior Management literature for some time. Despite this interest, there is a dearth of empirical research on the topic. The purpose of this study was to examine the effect of rules and goal setting in the workplace. Participants included two…

  20. Learning Strategies and Self-Efficacy as Predictors of Academic Performance: A Preliminary Study

    ERIC Educational Resources Information Center

    Yip, Michael C. W.

    2012-01-01

    Empirical research supports the idea that differences in academic performance among students are largely due to their different learning and study strategies. The strategies, in turn, affect the self-efficacy of the students. Two hundred university students were recruited to participate in this study by completing a revised Chinese version of the…

  1. Preliminary estimates of nucleon fluxes in a water target exposed to solar-flare protons: BRYNTRN versus Monte Carlo code

    NASA Technical Reports Server (NTRS)

    Shinn, Judy L.; Wilson, John W.; Lone, M. A.; Wong, P. Y.; Costen, Robert C.

    1994-01-01

    A baryon transport code (BRYNTRN) has previously been verified using available Monte Carlo results for a solar-flare spectrum as the reference. Excellent results were obtained, but the comparisons were limited to the available data on dose and dose equivalent for moderate penetration studies that involve minor contributions from secondary neutrons. To further verify the code, the secondary energy spectra of protons and neutrons are calculated using BRYNTRN and LAHET (Los Alamos High-Energy Transport code, which is a Monte Carlo code). These calculations are compared for three locations within a water slab exposed to the February 1956 solar-proton spectrum. Reasonable agreement was obtained when various considerations related to the calculational techniques and their limitations were taken into account. Although the Monte Carlo results are preliminary, it appears that the neutron albedo, which is not currently treated in BRYNTRN, might be a cause for the large discrepancy seen at small penetration depths. It also appears that the nonelastic neutron production cross sections in BRYNTRN may underestimate the number of neutrons produced in proton collisions with energies below 200 MeV. The notion that the poor energy resolution in BRYNTRN may cause a large truncation error in neutron elastic scattering requires further study.

  2. Estimating local ground-water flow conditions in a granitoid: Preliminary assessments in the Waldoboro Pluton Complex, Maine

    SciTech Connect

    Sidle, W.C.; Lee, P.Y.

    1995-03-01

    Periodic dry wells are reported by some homeowners in Knox and Lincoln Counties, Maine. These wells pump from the migmatitic Bucksport Fm. which is intermixed with the granitoids of the Waldoboro Pluton complex. Previous remote sensing and geologic mapping delineated marked northeast-trending structures in the WPC which were initially suspected as influencing ground-water flow for sustainable well yields. A sample area, Pemaquid Pond, in the WPC was studied in more detail including preliminary hydraulic testing of homeowner wells and ground-water flow modeling. Wells with sustainable and greater yields appear to be associated instead with zones of northwest-trending structures in granitoids not intermixed with the Bucksport Fm. Dry wells appear to be more prevalent among northeast-trending structures in areas where the migmatitic metamorphic rocks outcrop. Hydraulic studies, including pumping, slug, pressure, and borehole dilution testing, resulted in a wide range of calculated hydraulic conductivities. Dual-porosity flow modeling and geostatistical parameterization of the flow conditions suggest that the anisotropic hydraulic conductivity is near E-9 m/d.

  3. Preliminary Analysis of the General Performance and Mechanical Behavior of Irradiated FeCrAl Base Alloys and Weldments

    SciTech Connect

    Gussev, Maxim N.; Field, Kevin G.; Briggs, Samuel A.; Yamamoto, Yukinori

    2016-09-30

    The iron-based, iron-chromium-aluminum (FeCrAl) alloys are promising, robust materials for deployment in current and future nuclear power plants. This class of alloys demonstrates excellent performance in a range of environments and conditions, including high-temperature steam (>1000°C). Furthermore, these alloys have the potential to have prolonged survival under loss-of-coolant accident (LOCA) conditions compared to the more traditional cladding materials that are either Zr-based alloys or austenitic steels. However, one of the issues associated with FeCrAl alloys is cracking during welding. The present project investigates the possibility of mitigating welding-induced cracking via alloying and precise structure control of the weldments; in the frame work of the project, several advanced alloys were developed and are being investigated prior to and after neutron irradiation to provide insight into the radiation tolerance and mechanical performance of the weldments. The present report provides preliminary results on the post-irradiation characterization and mechanical tests performed during United States Fiscal Year (FY) 2016. Chapter 1 provides a general introduction, and Chapter 2 describes the alloy compositions, welding procedure, specimen geometry and manufacturing parameters. Also, a brief discussion of the irradiation at the High Flux Isotope Reactor (HFIR) is provided. Chapter 3 is devoted to the analysis of mechanical tests performed at the hot cell facility; tensile curves and mechanical properties are discussed in detail focusing on the irradiation temperature. Limited fractography results are also presented and analyzed. The discussion highlights the limitations of the testing within a hot cell. Chapter 4 underlines the advantages of in-situ testing and discusses the preliminary results obtained with newly developed miniature specimens. Specimens were moved to the Low Activation Materials Development and Analysis (LAMDA) laboratory and prepared for

  4. Preliminary Clinical Evaluation of a 4D-CBCT Estimation Technique using Prior Information and Limited-angle Projections

    PubMed Central

    Zhang, You; Yin, Fang-Fang; Pan, Tinsu; Vergalasova, Irina; Ren, Lei

    2015-01-01

    Background and Purpose A new technique has been previously reported to estimate high-quality 4D-CBCT using prior information and limited-angle projections. This study is to investigate its clinical feasibility through both phantom and patient studies. Materials and Methods The new technique used to estimate 4D-CBCT is called MMFD-NCC. It is based on the previously reported motion-modeling and free-form deformation (MMFD) method, with the introduction of normalized-cross-correlation (NCC) as a new similarity metric. The clinical feasibility of this technique was evaluated by assessing the accuracy of estimated anatomical structures in comparison to those in the ‘ground-truth’ reference 4D-CBCT, using data obtained from a physical phantom and three lung cancer patients. Both volume percentage error (VPE) and center-of-mass error (COME) of the estimated tumor volume were used as the evaluation metrics. Results The average VPE/COME of the tumor in the prior image was 257.1%/10.1 mm for the phantom study and 55.6%/3.8 mm for the patient study. Using only orthogonal-view 30° projections, the MMFD-NCC has reduced the corresponding values to 7.7% /1.2 mm and 9.6%/1.1 mm, respectively. Conclusions The MMFD-NCC technique is able to estimate 4D-CBCT images with geometrical accuracy of the tumor within 10% VPE and 2 mm COME, which can be used to improve the localization accuracy of radiotherapy. PMID:25818396

  5. Preliminary Assessment of Suomi-NPP VIIRS On-orbit Radiometric Performance

    NASA Technical Reports Server (NTRS)

    Oudrari, Hassan; DeLuccia, Frank; McIntire, Jeff; Moyer, David; Chiang, Vincent; Xiong, Xiao-xiong; Butler, James

    2012-01-01

    The Visible-Infrared Imaging Radiometer Suite (VIIRS) is a key instrument on-board the Suomi National Polar-orbiting Partnership (NPP) spacecraft that was launched on October 28th 2011. VIIRS was designed to provide moderate and imaging resolution of most of the globe twice daily. It is a wide-swath (3,040 km) cross-track scanning radiometer with spatial resolutions of 370.and 740 m at nadir for imaging and moderate bands, respectively. It has 22 spectral bands covering the spectrum between 0.412 11m and 12.01 11m, including 14 reflective solar bands (RSB), 7 thermal emissive bands (TEB), and 1 day-night band (ON B). VIIRS observations are used to generate 22 environmental data products (EORs). This paper will briefly describe NPP VIIRS calibration strategies performed by the independent government team, for the initial on-orbit Intensive Calibration and Validation (ICV) activities. In addition, this paper will provide an early assessment of the sensor on-orbit radiometric performance, such as the sensor signal to noise ratios (SNRs), dual gain transition verification, dynamic range and linearity, reflective bands calibration based on the solar diffuser (SO) and solar diffuser stability monitor (SOSM), and emissive bands calibration based on the on-board blackbody calibration (OBC). A comprehensive set of performance metrics generated during the pre-launch testing program will be compared to VIIRS on-orbit early performance, and a plan for future cal/val activities and performance enhancements will be presented.

  6. Validation of the functional and social performance - DSF-84 checklist: preliminary study.

    PubMed

    Monteiro, Rogeria Pimentel de Araujo; Pfeifer, Luzia Iara; Soares, Iraci; Dos Santos, Alex de Assis Santos; Sousa, Nelson

    2013-08-01

    To develop, implement and validate an instrument for assessing the functional and social performance of young male adults with lower limb amputees based on the international classification of functionality, incapacity, and health. Developed the instrument, the items were grouped into domains (organic aspects - OA, daily activities - DA, performance components - PC, social participation - SP and environmental factors - EF) for statistical analysis. The implementation of the instrument was filmed for validation. Four assessors watched the films on two occasions and gave scores. Intra-class correlation was used to evaluate intra- and inter-rater reproducibility and to the internal consistency was calculated by Cronbach's alpha and the criterion validity was assessed by Student's t-test and the Mann-Whitney U-test. The results showed good reliability in the scores for OA, DA, PC and SP domains and a reasonable reliability for the EF domain. The differences between assessors performed by the analysis of variance were not significant. The reliability intra-rater, performed through the test-retest method, showed in all domains high levels of intra-rater correspondence. The results show the validity and reliability of DSF-84 to young male adults with amputation of the lower limb, being useful for this population. In this study have been developed, implemented, and validated an instrument (DSF-84) for assessing the functional and social performance of young male adults with lower limb amputees based on the ICF. The results show the validity and reliability of DSF-84 to young male adults with amputation of the lower limb, being useful for this population.

  7. Performance evaluation of the Particle Smoother with Sequential Importance Resampling for soil hydraulic parameter estimation

    NASA Astrophysics Data System (ADS)

    Montzka, C.; Moradkhani, H.; Han, X.; Hendricks Franssen, H. J.; Puetz, T.; Vereecken, H.

    2014-12-01

    An adequate description of soil hydraulic properties is essential for a good performance of hydrological forecasts and soil water fluxes. So far, several studies showed that data assimilation could reduce the parameter uncertainty by considering soil moisture observations. However, these observations and also the model forcings were recorded with a specific measurement error. It seems a logical step to base state updating and parameter estimation on observations made at multiple time steps, in order to reduce the influence of outliers at single time steps given measurement errors and unknown model forcings. Such outliers could result in erroneous state estimation as well as inadequate parameters. This has been one of the reasons to use a smoothing technique as implemented for Bayesian data assimilation methods such as the Ensemble Kalman Filter (i.e. Ensemble Kalman Smoother). In this contribution we present a Particle Smoother (SIR-PS) with sequentially smoothing of particle weights for state and parameter resampling within a time window as opposed to the single time step data assimilation used in filtering techniques. This can be seen as an intermediate variant between a parameter estimation technique using global optimization with estimation of single parameter sets valid for the whole period, and sequential Monte Carlo techniques with estimation of parameter sets evolving from one time step to another. The aims are i) to improve the soil moisture forecast by estimating hydraulic parameters, ii) to reduce the impact of single erroneous model inputs/observations by a smoothing method, and iii) to evaluate the performance of the SIR-PS as opposed to the SIR-PF using different ensemble and smoothing window sizes. In order to validate the performance of the proposed method for real world conditions, experimental data obtained from a two year lysimeter study were used.

  8. Preliminary estimates of residence times and apparent ages of ground water in the Chesapeake Bay watershed, and water-quality data from a survey of springs

    USGS Publications Warehouse

    Focazio, Michael J.; Plummer, L. Neil; Bohlke, John K.; Busenberg, Eurybiades; Bachman, L. Joseph; Powars, David S.

    1998-01-01

    Knowledge of the residence times of the ground-water systems in Chesapeake Bay watershed helps resource managers anticipate potential delays between implementation of land-management practices and any improve-ments in river and estuary water quality. This report presents preliminary estimates of ground-water residence times and apparent ages of water in the shallow aquifers of the Chesapeake Bay watershed. A simple reservoir model, published data, and analyses of spring water were used to estimate residence times and apparent ages of ground-water discharge. Ranges of aquifer hydraulic characteristics throughout the Bay watershed were derived from published literature and were used to estimate ground-water residence times on the basis of a simple reservoir model. Simple combinations of rock type and physiographic province were used to delineate hydrogeomorphic regions (HGMR?s) for the study area. The HGMR?s are used to facilitate organization and display of the data and analyses. Illustrations depicting the relation of aquifer characteristics and associated residence times as a continuum for each HGMR were developed. In this way, the natural variation of aquifer characteristics can be seen graphically by use of data from selected representative studies. Water samples collected in September and November 1996, from 46 springs throughout the watershed were analyzed for chlorofluorocarbons (CFC?s) to estimate the apparent age of ground water. For comparison purposes, apparent ages of water from springs were calculated assuming piston flow. Additi-onal data are given to estimate apparent ages assuming an exponential distribution of ages in spring discharge. Additionally, results from previous studies of CFC-dating of ground water from other springs and wells in the watershed were compiled. The CFC data, and the data on major ions, nutrients, and nitrogen isotopes in the water collected from the 46 springs are included in this report. The apparent ages of water

  9. The effect of cluster size imbalance and covariates on the estimation performance of quadratic inference functions.

    PubMed

    Westgate, Philip M; Braun, Thomas M

    2012-09-10

    Generalized estimating equations (GEE) are commonly used for the analysis of correlated data. However, use of quadratic inference functions (QIFs) is becoming popular because it increases efficiency relative to GEE when the working covariance structure is misspecified. Although shown to be advantageous in the literature, the impacts of covariates and imbalanced cluster sizes on the estimation performance of the QIF method in finite samples have not been studied. This cluster size variation causes QIF's estimating equations and GEE to be in separate classes when an exchangeable correlation structure is implemented, causing QIF and GEE to be incomparable in terms of efficiency. When utilizing this structure and the number of clusters is not large, we discuss how covariates and cluster size imbalance can cause QIF, rather than GEE, to produce estimates with the larger variability. This occurrence is mainly due to the empirical nature of weighting QIF employs, rather than differences in estimating equations classes. We demonstrate QIF's lost estimation precision through simulation studies covering a variety of general cluster randomized trial scenarios and compare QIF and GEE in the analysis of data from a cluster randomized trial. Copyright © 2012 John Wiley & Sons, Ltd.

  10. RETROSPECTIVE ESTIMATION OF PATIENT DOSE-AREA PRODUCT IN THORACIC SPINE TOMOSYNTHESIS PERFORMED USING VOLUMERAD.

    PubMed

    Båth, Magnus; Söderman, Christina; Svalkvist, Angelica

    2016-06-01

    The aim of this study was to evaluate the use of a recently developed method of retrospectively estimating the patient dose-area product (DAP) of a chest tomosynthesis examination, performed using VolumeRAD, in thoracic spine tomosynthesis and to determine the necessary field-size correction factor. Digital imaging and communications in medicine (DICOM) data for the projection radiographs acquired during a thoracic spine tomosynthesis examination were retrieved directly from the modality for 17 patients. Using the previously developed method, an estimated DAP for the tomosynthesis examination was determined from DICOM data in the scout image. By comparing the estimated DAP with the actual DAP registered for the projection radiographs, a field-size correction factor was determined. The field-size correction factor for thoracic spine tomosynthesis was determined to 0.92. Applying this factor to the DAP estimated retrospectively, the maximum difference between the estimated DAP and the actual DAP was <3 %. In conclusion, the previously developed method of retrospectively estimating the DAP in chest tomosynthesis can be applied to thoracic spine tomosynthesis. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Unique criterion to estimate the performances of some laser diode range finders

    NASA Astrophysics Data System (ADS)

    Journet, Bernard A.; Bazin, Gaelle; Durieu, Cecile

    2001-09-01

    The purpose of this paper is to present a general method to estimate the intrinsic performances of some laser range finders based on flight time measurement. Classically this flight time can be measured directly, or after a conversion into a phase shift, or into a beat frequency. We prose here a criterion based on signal processing notions, as matched filtering to get the best detection, and ambiguity function to estimate the quality of the detection. The concept of characteristic length is introduced and applied to the different kind of laser range finders, which suggest a new possibility for flight time measurement.

  12. Classification Systems for Individual Differences in Multiple-task Performance and Subjective Estimates of Workload

    NASA Technical Reports Server (NTRS)

    Damos, D. L.

    1984-01-01

    Human factors practitioners often are concerned with mental workload in multiple-task situations. Investigations of these situations have demonstrated repeatedly that individuals differ in their subjective estimates of workload. These differences may be attributed in part to individual differences in definitions of workload. However, after allowing for differences in the definition of workload, there are still unexplained individual differences in workload ratings. The relation between individual differences in multiple-task performance, subjective estimates of workload, information processing abilities, and the Type A personality trait were examined.

  13. High performance thin layer chromatographic method for simultaneous estimation of Ibuprofen and pseudoephedrine hydrochloride.

    PubMed

    Chitlange, S S; Sakarkar, D M; Wankhede, S B; Wadodkar, S G

    2008-01-01

    High performance thin layer chromatographic method is developed for simultaneous estimation of ibuprofen and pseudoephedrine hydrochloride in tablets. Silica gel 60F(254) plates were used as stationary phase and t.butanol: ethyl acetate: glacial acetic acid: water (7:4:2:2 v/v) as mobile phase. Wavelength selected for analysis was 254 nm. Percent estimation of ibuprofen and pseudoephedrine hydrochloride was found to be 99.56% and 98.77%, respectively. Percent recovery for both the drugs was found in the range of 98.27% to 100.91%, respectively.

  14. A Simple Analytic Model for Estimating Mars Ascent Vehicle Mass and Performance

    NASA Technical Reports Server (NTRS)

    Woolley, Ryan C.

    2014-01-01

    The Mars Ascent Vehicle (MAV) is a crucial component in any sample return campaign. In this paper we present a universal model for a two-stage MAV along with the analytic equations and simple parametric relationships necessary to quickly estimate MAV mass and performance. Ascent trajectories can be modeled as two-burn transfers from the surface with appropriate loss estimations for finite burns, steering, and drag. Minimizing lift-off mass is achieved by balancing optimized staging and an optimized path-to-orbit. This model allows designers to quickly find optimized solutions and to see the effects of design choices.

  15. Monte-Carlo Estimation of the Inflight Performance of the GEMS Satellite X-Ray Polarimeter

    NASA Technical Reports Server (NTRS)

    Kitaguchi, Takao; Tamagawa, Toru; Hayato, Asami; Enoto, Teruaki; Yoshikawa, Akifumi; Kaneko, Kenta; Takeuchi, Yoko; Black, Kevin; Hill, Joanne; Jahoda, Keith; hide

    2014-01-01

    We report a Monte-Carlo estimation of the in-orbit performance of a cosmic X-ray polarimeter designed to be installed on the focal plane of a small satellite. The simulation uses GEANT for the transport of photons and energetic particles and results from Magboltz for the transport of secondary electrons in the detector gas. We validated the simulation by comparing spectra and modulation curves with actual data taken with radioactive sources and an X-ray generator. We also estimated the in-orbit background induced by cosmic radiation in low Earth orbit.

  16. A Simple Analytic Model for Estimating Mars Ascent Vehicle Mass and Performance

    NASA Technical Reports Server (NTRS)

    Woolley, Ryan C.

    2014-01-01

    The Mars Ascent Vehicle (MAV) is a crucial component in any sample return campaign. In this paper we present a universal model for a two-stage MAV along with the analytic equations and simple parametric relationships necessary to quickly estimate MAV mass and performance. Ascent trajectories can be modeled as two-burn transfers from the surface with appropriate loss estimations for finite burns, steering, and drag. Minimizing lift-off mass is achieved by balancing optimized staging and an optimized path-to-orbit. This model allows designers to quickly find optimized solutions and to see the effects of design choices.

  17. Monte-Carlo Estimation of the Inflight Performance of the GEMS Satellite X-Ray Polarimeter

    NASA Technical Reports Server (NTRS)

    Kitaguchi, Takao; Tamagawa, Toru; Hayato, Asami; Enoto, Teruaki; Yoshikawa, Akifumi; Kaneko, Kenta; Takeuchi, Yoko; Black, Kevin; Hill, Joanne; Jahoda, Keith; Krizmanic, John; Sturner, Steve; Griffiths, Scott; Kaaret, Philip; Marlowe, Hannah

    2014-01-01

    We report a Monte-Carlo estimation of the in-orbit performance of a cosmic X-ray polarimeter designed to be installed on the focal plane of a small satellite. The simulation uses GEANT for the transport of photons and energetic particles and results from Magboltz for the transport of secondary electrons in the detector gas. We validated the simulation by comparing spectra and modulation curves with actual data taken with radioactive sources and an X-ray generator. We also estimated the in-orbit background induced by cosmic radiation in low Earth orbit.

  18. Influence of the management strategy model on estimating water system performance under climate change

    NASA Astrophysics Data System (ADS)

    Francois, Baptiste; Hingray, Benoit; Creutin, Jean-Dominique; Hendrickx, Frederic

    2015-04-01

    The performance of water systems used worldwide for the management of water resources is expected to be influenced by future changes in regional climates and water uses. Anticipating possible performance changes of a given system requires a modeling chain simulating its management. Operational management is usually not trivial especially when several conflicting objectives have to be accounted for. Management models are therefore often a crude representation of the real system and they only approximate its performance. Estimated performance changes are expected to depend on the management model used, but this is often not assessed. This communication analyzes the influence of the management strategy representation on the performance of an Alpine reservoir (Serre-Ponçon, South-East of France) for which irrigation supply, hydropower generation and recreational activities are the main objectives. We consider three ways to construct the strategy named as clear-, short- and far-sighted management. They are based on different forecastability degrees of seasonal inflows into the reservoir. The strategies are optimized using a Dynamic Programming algorithm (deterministic for clear-sighted and implicit stochastic for short- and far-sighted). System performance is estimated for an ensemble of future hydro-meteorological projections obtained in the RIWER2030 research project (http://www.lthe.fr/RIWER2030/) from a suite of climate experiments from the EU - ENSEMBLES research project. Our results show that changes in system performance is much more influenced by changes in hydro-meteorological variables than by the choice of strategy modeling. They also show that a simple strategy representation (i.e. clear-sighted management) leads to similar estimates of performance modifications than those obtained with a representation supposedly closer to real world (i.e. the far-sighted management). The Short-Sighted management approach lead to significantly different results, especially

  19. A Preliminary Investigation into Cognitive Aptitudes Predictive of Overall MQ-1 Predator Pilot Qualification Training Performance

    DTIC Science & Technology

    2015-11-06

    multivariate range restriction corrections. Performing range restriction adjustments on small sample sizes may lead to results with a 50% chance or less...the effects of range restriction assumptions on needed sample size . J Appl Psychol. 1983; 68(3):374-381. 20. Raju NS, Edwards JE, LoVerde MA...Corrected formulas for computing sample sizes under indirect range restriction. J Appl Psychol. 1985; 70(3):565-566. 21. Lawley DN. IV.—A note on Karl

  20. Cognitive predictors of skilled performance with an advanced upper limb multifunction prosthesis: a preliminary analysis.

    PubMed

    Hancock, Laura; Correia, Stephen; Ahern, David; Barredo, Jennifer; Resnik, Linda

    2017-07-01

    Purpose The objectives were to 1) identify major cognitive domains involved in learning to use the DEKA Arm; 2) specify cognitive domain-specific skills associated with basic versus advanced users; and 3) examine whether baseline memory and executive function predicted learning. Method Sample included 35 persons with upper limb amputation. Subjects were administered a brief neuropsychological test battery prior to start of DEKA Arm training, as well as physical performance measures at the onset of, and following training. Multiple regression models controlling for age and including neuropsychological tests were developed to predict physical performance scores. Prosthetic performance scores were divided into quartiles and independent samples t-tests compared neuropsychological test scores of advanced scorers and basic scorers. Baseline neuropsychological test scores were used to predict change in scores on physical performance measures across time. Results Cognitive domains of attention and processing speed were statistically significantly related to proficiency of DEKA Arm use and predicted level of proficiency. Conclusions Results support use of neuropsychological tests to predict learning and use of a multifunctional prosthesis. Assessment of cognitive status at the outset of training may help set expectations for the duration and outcomes of treatment. Implications for Rehabilitation Cognitive domains of attention and processing speed were significantly related to level of proficiencyof an advanced multifunctional prosthesis (the DEKA Arm) after training. Results provide initial support for the use of neuropsychological tests to predict advanced learningand use of a multifunctional prosthesis in upper-limb amputees. Results suggest that assessment of patients' cognitive status at the outset of upper limb prosthetictraining may, in the future, help patients, their families and therapists set expectations for theduration and intensity of training and may help set

  1. Preliminary Assessment of Soldier Performance on Land Navigation and Map Reading Tasks (1982)

    DTIC Science & Technology

    1985-09-01

    Determine a magnetic azimuth using a compass . Task 8: Identify terrain features (natural and manmade) on the map. Task 9: Determine the grid coordinates...Number 7: Determine a Magnetic Azimuth Using a Compass * Frequency of Performance Measures aOccurrence 1. (Did not) remove helmet and weapon and 0b...Results Presented by Month for POIQT Task Number 7: Determine a Magnetic Azimuth Using a Compass Month Total N # Gos % Gos # No Gos % No Gos Jan 1629

  2. Effects of Head Impact Acceleration on Human Performance: Overview and Preliminary Battery Identification.

    DTIC Science & Technology

    1983-05-01

    Rimel , Giordani, Barth, Boll, & Jane, 1981). Human performance disruptions caused by impact acceleration are the focus of the present investigation...National Safety Council, 1979; Rimel , et al., 1981; Sances, Weber, Larson, et al., 1981). Part of the NBDL modeling effort involves the use of...Unterharnscheldt, 1983). Transient reduction in the amplitude of the cortical SSEPs occurred as a linear function of the level of frontal impact (-X

  3. Preliminary evidence for performance enhancement following parietal lobe stimulation in Developmental Dyscalculia.

    PubMed

    Iuculano, Teresa; Cohen Kadosh, Roi

    2014-01-01

    Nearly 7% of the population exhibit difficulties in dealing with numbers and performing arithmetic, a condition named Developmental Dyscalculia (DD), which significantly affects the educational and professional outcomes of these individuals, as it often persists into adulthood. Research has mainly focused on behavioral rehabilitation, while little is known about performance changes and neuroplasticity induced by the concurrent application of brain-behavioral approaches. It has been shown that numerical proficiency can be enhanced by applying a small-yet constant-current through the brain, a non-invasive technique named transcranial electrical stimulation (tES). Here we combined a numerical learning paradigm with transcranial direct current stimulation (tDCS) in two adults with DD to assess the potential benefits of this methodology to remediate their numerical difficulties. Subjects learned to associate artificial symbols to numerical quantities within the context of a trial and error paradigm, while tDCS was applied to the posterior parietal cortex (PPC). The first subject (DD1) received anodal stimulation to the right PPC and cathodal stimulation to the left PPC, which has been associated with numerical performance's improvements in healthy subjects. The second subject (DD2) received anodal stimulation to the left PPC and cathodal stimulation to the right PPC, which has been shown to impair numerical performance in healthy subjects. We examined two indices of numerical proficiency: (i) automaticity of number processing; and (ii) mapping of numbers onto space. Our results are opposite to previous findings with non-dyscalculic subjects. Only anodal stimulation to the left PPC improved both indices of numerical proficiency. These initial results represent an important step to inform the rehabilitation of developmental learning disabilities, and have relevant applications for basic and applied research in cognitive neuroscience, rehabilitation, and education.

  4. Preliminary evidence for performance enhancement following parietal lobe stimulation in Developmental Dyscalculia

    PubMed Central

    Iuculano, Teresa; Cohen Kadosh, Roi

    2014-01-01

    Nearly 7% of the population exhibit difficulties in dealing with numbers and performing arithmetic, a condition named Developmental Dyscalculia (DD), which significantly affects the educational and professional outcomes of these individuals, as it often persists into adulthood. Research has mainly focused on behavioral rehabilitation, while little is known about performance changes and neuroplasticity induced by the concurrent application of brain-behavioral approaches. It has been shown that numerical proficiency can be enhanced by applying a small—yet constant—current through the brain, a non-invasive technique named transcranial electrical stimulation (tES). Here we combined a numerical learning paradigm with transcranial direct current stimulation (tDCS) in two adults with DD to assess the potential benefits of this methodology to remediate their numerical difficulties. Subjects learned to associate artificial symbols to numerical quantities within the context of a trial and error paradigm, while tDCS was applied to the posterior parietal cortex (PPC). The first subject (DD1) received anodal stimulation to the right PPC and cathodal stimulation to the left PPC, which has been associated with numerical performance's improvements in healthy subjects. The second subject (DD2) received anodal stimulation to the left PPC and cathodal stimulation to the right PPC, which has been shown to impair numerical performance in healthy subjects. We examined two indices of numerical proficiency: (i) automaticity of number processing; and (ii) mapping of numbers onto space. Our results are opposite to previous findings with non-dyscalculic subjects. Only anodal stimulation to the left PPC improved both indices of numerical proficiency. These initial results represent an important step to inform the rehabilitation of developmental learning disabilities, and have relevant applications for basic and applied research in cognitive neuroscience, rehabilitation, and education

  5. Emotional intelligence and its correlation to performance as a resident: a preliminary study.

    PubMed

    Talarico, Joseph F; Metro, David G; Patel, Rita M; Carney, Patricia; Wetmore, Amy L

    2008-03-01

    To test the hypothesis that emotional intelligence, as measured by the Bar-On Emotional Quotient Inventory (EQ-I) 125 (Multi Health Systems, Toronto, Ontario, Canada) personal inventory, would correlate with resident performance. Prospective survey. University-affiliated, multiinstitutional anesthesiology residency program. Current clinical anesthesiology years one to three (PGY 2-4) anesthesiology residents enrolled in the University of Pittsburgh Anesthesiology Residency Program. Participants confidentially completed the Bar-On EQ-I 125 survey. Results of the individual EQ-I 125 and daily evaluations by the faculty of the residency program were compiled and analyzed. There was no positive correlation between any facet of emotional intelligence and resident performance. There was statistically significant negative correlation (-0.40; P < 0.05) between assertiveness and the "American Board of Anesthesiology essential attributes" component of the resident evaluation. Emotional intelligence, as measured by the Bar-On EQ-I personal inventory, does not strongly correlate to resident performance as defined at the University of Pittsburgh.

  6. Effect of tone-based sound stimulation on balance performance of normal subjects: preliminary investigation.

    PubMed

    Pagnacco, Guido; Klotzek, Adam S; Carrick, Frederick R; Wright, Cameron H G; Oggero, Elena

    2015-01-01

    Sound is known to affect the human brain, hence sound or music therapy is sometimes used to improve a subject's physicaland mental health. In this study, the effects sound stimulation has on balance were investigated by means of computerizeddynamic posturography tests performed with eyes closed on an unstable surface using a CAPS® system, exceeding theInternational Society for Posture and Gait Research (ISPGR) recommended metrological performance standards. Subjectswere tested without listening to any music (baseline), listening to “pure music”, and listening to the same music with differenttones embedded into it (one for each key). We found that different subjects react differently to different tones. Music alonedid not have a statistically significant effect on balance compared to the baseline, but the “best” tone significantly improvedbalance compared to the baseline or the “pure music” conditions. Furthermore, the “worst” tone reduced the balancecompared to “pure music”, but the reduction was not statistically significant relative to the baseline. The results thereforeindicate that, at least relative to balance performance, the tone-based sound stimulation we investigated is effective andinherently safe, but that tone selection depends on the individual subject.

  7. A Preliminary Exploration of Concussion and Strength Performance in Youth Ice Hockey Players.

    PubMed

    Reed, N; Taha, T; Monette, G; Keightley, M

    2016-08-01

    The objective of this study was to describe the effect of concussion on upper and lower body strength in children and youth athletes. The participant group was made up of 178 unique male and female ice hockey players (ages 8-14 years). Using a 3-year prospective longitudinal research design, baseline and post-concussion data on hand grip strength, jump tests, and leg maximal voluntary contraction were collected. Using a linear mixed-effects model, no significant differences were found when comparing the baseline strength performance of individuals who went on to experience a concussion and those who did not. When accounting for sex, multiple concussions, and ongoing changes in strength associated with age, weaker hand grip scores were found following concussion while participants were still symptomatic. Lower squat jump heights were achieved while participants were symptomatic as well as when they were no longer self-reporting symptoms associated with concussion. This study represents an initial step towards better understanding strength performance following concussion that may limit the on and off ice performance of youth ice hockey players, as well as predispose youth to subsequent injuries.

  8. Performance environment and nested task constraints influence long jump approach run: a preliminary study.

    PubMed

    Panteli, Flora; Smirniotou, Athanasia; Theodorou, Apostolos

    2016-01-01

    The purpose of the study was to investigate possible changes at step pattern and technical performance of the long jump approach run in seven young long jumpers by modifying the performance environment (long jump runway versus track lane) and the nested actions (run-through with take-off versus complete long jump). Our findings suggest that the step pattern and technical aspects of the approach run are affected by environmental context and nested task constraints. In terms of environmental context, it appears that practising the training routine of run-through followed by take-off on the long jump runway allows athletes to simulate competition conditions in terms of step regulation and technical efficacy. The task of run-through followed by take-off on the track lane failed to initiate visual perception, step regulation and technical efficiency at the steps preceding the instant of take-off. In terms of nested task constraints, when run-ups were followed by jump for distance instead of only a take-off, a higher level of consistency was achieved and step regulation was based on perception-action coupling. Practising long jump run-up accuracy at a setting not containing the informational elements of the performance environment fails to develop the key elements of the skill.

  9. Definition and preliminary design of the Laser Atmospheric Wind Sounder (LAWS) phase 1. Volume 3: Program cost estimates

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Cost estimates for phase C/D of the laser atmospheric wind sounder (LAWS) program are presented. This information provides a framework for cost, budget, and program planning estimates for LAWS. Volume 3 is divided into three sections. Section 1 details the approach taken to produce the cost figures, including the assumptions regarding the schedule for phase C/D and the methodology and rationale for costing the various work breakdown structure (WBS) elements. Section 2 shows a breakdown of the cost by WBS element, with the cost divided in non-recurring and recurring expenditures. Note that throughout this volume the cost is given in 1990 dollars, with bottom line totals also expressed in 1988 dollars (1 dollar(88) = 0.93 1 dollar(90)). Section 3 shows a breakdown of the cost by year. The WBS and WBS dictionary are included as an attachment to this report.

  10. Performance, cost and environmental assessment of gasification-based electricity in India: A preliminary analysis

    NASA Astrophysics Data System (ADS)

    Rani, Abha; Singh, Udayan; Jayant; Singh, Ajay K.; Sankar Mahapatra, Siba

    2017-07-01

    Coal gasification processes are crucial to decarbonisation in the power sector. While underground coal gasification (UCG) and integrated gasification combined cycle (IGCC) are different in terms of the site of gasification, they have considerable similarities in terms of the types of gasifiers used. Of course, UCG offers some additional advantages such as reduction of the fugitive methane emissions accompanying the coal mining process. Nevertheless, simulation of IGCC plants involving surface coal gasification is likely to give reasonable indication of the 3E (efficiency, economics and emissions) prospects of the gasification pathway towards electricity. This paper will aim at Estimating 3E impacts (efficiency, environment, economics) of gasification processes using simulation carried out in the Integrated Environmental Control Model (IECM) software framework. Key plant level controls which will be studied in this paper will be based on Indian financial regulations and operating costs which are specific to the country. Also, impacts of CO2 capture and storage (CCS) in these plants will be studied. The various parameters that can be studied are plant load factor, impact of coal quality and price, type of CO2 capture process, capital costs etc. It is hoped that relevant insights into electricity generation from gasification may be obtained with this paper.

  11. Preliminary estimate of the amplification of possible earthquake ground motion at a site in Charleston County, South Carolina

    USGS Publications Warehouse

    Wheeler, Russell L.; Cramer, Chris H.

    2000-01-01

    We estimate site amplification at the location of a proposed bridge near Charleston, South Carolina. Model calculations indicate that amplification at periods of 1 s and longer is likely to be strongly influenced by the effects of a large contrast in shear-wave velocity at a depth of approximately 1 km (3,000 ft). On-site borehole data, regional geological and geophysical information, and data from a geologically similar setting near Memphis, Tennessee allowed us to estimate profiles of shear-wave velocity, shear-wave attenuation, and density from ground level down to metamorphic and igneous rocks that are approximately 3 km (9,500 ft) beneath the site. We modeled amplifications that would be produced at the surface and at the top and bottom of the Cooper Marl. Amplification estimates that are based only on the shallow shear-wave structure, for example in the upper 100 m (300 ft), can severely underestimate long-period amplification at the site. Additional modeling could help determine whether new data should be collected, to resolve remaining uncertainties about likely amplification.

  12. Preliminary Upper Estimate of Peak Currents in Transcranial Magnetic Stimulation at Distant Locations From a TMS Coil.

    PubMed

    Makarov, Sergey N; Yanamadala, Janakinadh; Piazza, Matthew W; Helderman, Alex M; Thang, Niang S; Burnham, Edward H; Pascual-Leone, Alvaro

    2016-09-01

    Transcranial magnetic stimulation (TMS) is increasingly used as a diagnostic and therapeutic tool for numerous neuropsychiatric disorders. The use of TMS might cause whole-body exposure to undesired induced currents in patients and TMS operators. The aim of this study is to test and justify a simple analytical model known previously, which may be helpful as an upper estimate of eddy current density at a particular distant observation point for any body composition and any coil setup. We compare the analytical solution with comprehensive adaptive mesh refinement-based FEM simulations of a detailed full-body human model, two coil types, five coil positions, about 100 000 observation points, and two distinct pulse rise times; thus, providing a representative number of different datasets for comparison, while also using other numerical data. Our simulations reveal that, after a certain modification, the analytical model provides an upper estimate for the eddy current density at any location within the body. In particular, it overestimates the peak eddy currents at distant locations from a TMS coil by a factor of 10 on average. The simple analytical model tested in this study may be valuable as a rapid method to safely estimate levels of TMS currents at different locations within a human body. At present, safe limits of general exposure to TMS electric and magnetic fields are an open subject, including fetal exposure for pregnant women.

  13. Performance metric development for a group state estimator in airborne UHF GMTI applications

    NASA Astrophysics Data System (ADS)

    Elwell, Ryan A.

    2013-05-01

    This paper describes the development and implementation of evaluation metrics for group state estimator (GSE, i.e. group tracking) algorithms. Key differences between group tracker metrics and individual tracker metrics are the method used for track-to-truth association and the characterization of group raid size. Another significant contribution of this work is the incorporation of measured radar performance in assessing tracker performance. The result of this work is a set of measures of performance derived from canonical individual target tracker metrics, extended to characterize the additional information provided by a group tracker. The paper discusses additional considerations in group tracker evaluation, including the definition of a group and group-to-group confusion. Metrics are computed on real field data to provide examples of real-world analysis, demonstrating an approach which provides characterization of group tracker performance, independent of the sensor's performance.

  14. Accounting for estimated IQ in neuropsychological test performance with regression-based techniques.

    PubMed

    Testa, S Marc; Winicki, Jessica M; Pearlson, Godfrey D; Gordon, Barry; Schretlen, David J

    2009-11-01

    Regression-based normative techniques account for variability in test performance associated with multiple predictor variables and generate expected scores based on algebraic equations. Using this approach, we show that estimated IQ, based on oral word reading, accounts for 1-9% of the variability beyond that explained by individual differences in age, sex, race, and years of education for most cognitive measures. These results confirm that adding estimated "premorbid" IQ to demographic predictors in multiple regression models can incrementally improve the accuracy with which regression-based norms (RBNs) benchmark expected neuropsychological test performance in healthy adults. It remains to be seen whether the incremental variance in test performance explained by estimated "premorbid" IQ translates to improved diagnostic accuracy in patient samples. We describe these methods, and illustrate the step-by-step application of RBNs with two cases. We also discuss the rationale, assumptions, and caveats of this approach. More broadly, we note that adjusting test scores for age and other characteristics might actually decrease the accuracy with which test performance predicts absolute criteria, such as the ability to drive or live independently.

  15. Cooling via one hand improves physical performance in heat-sensitive individuals with Multiple Sclerosis: A preliminary study

    PubMed Central

    Grahn, Dennis A; Murray, Julie vLS; Heller, H Craig

    2008-01-01

    Background Many individuals afflicted with multiple sclerosis (MS) experience a transient worsening of symptoms when body temperature increases due to ambient conditions or physical activity. Resulting symptom exacerbations can limit performance. We hypothesized that extraction of heat from the body through the subcutaneous retia venosa that underlie the palmar surfaces of the hands would reduce exercise-related heat stress and thereby increase the physical performance capacity of heat-sensitive individuals with MS. Methods Ten ambulatory MS patients completed one or more randomized paired trials of walking on a treadmill in a temperate environment with and without cooling. Stop criteria were symptom exacerbation and subjective fatigue. The cooling treatment entailed inserting one hand into a rigid chamber through an elastic sleeve that formed an airtight seal around the wrist. A small vacuum pump created a -40 mm Hg subatmospheric pressure enviinside the chamber where the palmar surface of the hand rested on a metal surface maintained at 18–22°C. During the treatment trials, the device was suspended from above the treadmill on a bungee cord so the subjects could comfortably keep a hand in the device without having to bear its weight while walking on the treadmill. Results When the trials were grouped by treatment only, cooling treatment increased exercise durations by 33% (43.6 ± 17.1 min with treatment vs. 32.8 ± 10.9 min. without treatment, mean ± SD, p < 5.0·10-6, paired t-test, n = 26). When the average values were calculated for the subjects who performed multiple trials before the treatment group results were compared, cooling treatment increased exercise duration by 35% (42.8 ± 16.4 min with treatment vs. 31.7 ± 9.8 min. without treatment, mean ± SD, p < 0.003, paired t-test, n = 10). Conclusion These preliminary results suggest that utilization of the heat transfer capacity of the non-hairy skin surfaces can enable temperature

  16. Cooling via one hand improves physical performance in heat-sensitive individuals with multiple sclerosis: a preliminary study.

    PubMed

    Grahn, Dennis A; Murray, Julie Vls; Heller, H Craig

    2008-05-12

    Many individuals afflicted with multiple sclerosis (MS) experience a transient worsening of symptoms when body temperature increases due to ambient conditions or physical activity. Resulting symptom exacerbations can limit performance. We hypothesized that extraction of heat from the body through the subcutaneous retia venosa that underlie the palmar surfaces of the hands would reduce exercise-related heat stress and thereby increase the physical performance capacity of heat-sensitive individuals with MS. Ten ambulatory MS patients completed one or more randomized paired trials of walking on a treadmill in a temperate environment with and without cooling. Stop criteria were symptom exacerbation and subjective fatigue. The cooling treatment entailed inserting one hand into a rigid chamber through an elastic sleeve that formed an airtight seal around the wrist. A small vacuum pump created a -40 mm Hg subatmospheric pressure enviinside the chamber where the palmar surface of the hand rested on a metal surface maintained at 18-22 degrees C. During the treatment trials, the device was suspended from above the treadmill on a bungee cord so the subjects could comfortably keep a hand in the device without having to bear its weight while walking on the treadmill. When the trials were grouped by treatment only, cooling treatment increased exercise durations by 33% (43.6 +/- 17.1 min with treatment vs. 32.8 +/- 10.9 min. without treatment, mean +/- SD, p < 5.0.10-6, paired t-test, n = 26). When the average values were calculated for the subjects who performed multiple trials before the treatment group results were compared, cooling treatment increased exercise duration by 35% (42.8 +/- 16.4 min with treatment vs. 31.7 +/- 9.8 min. without treatment, mean +/- SD, p < 0.003, paired t-test, n = 10). These preliminary results suggest that utilization of the heat transfer capacity of the non-hairy skin surfaces can enable temperature-sensitive individuals with MS to extend

  17. Predictive performance of different kidney function estimation equations in lung transplant patients.

    PubMed

    Degen, Dov A; Janardan, Jyotsna; Barraclough, Katherine A; Schneider, Hans G; Barber, Thomas; Barton, Howard; Snell, Gregory; Levvey, Bronwyn; Walker, Rowan G

    2017-05-01

    There has been limited examination of the performance of glomerular filtration rate estimation (eGFR) equations in lung transplant populations. This study aimed to compare the performance of serum creatinine and cystatin C based eGFR equations with Tc-99m diethylenetriaminepentaacetic acid (DTPA) GFR measurements in individuals with end-stage lung disease, either prior to, or following, lung transplantation. In this prospective observational study, participants underwent GFR measurements with Tc-99m Pentetate. Measured results were compared with GFR estimates derived from estimation equations [4-variable Modification of Diet in Renal Disease, Cockcroft-Gault, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine, cystatin C and creatinine-cystatin C combined equations]. Ninety-seven individuals were studied (77 post- and 20 wait-listed for transplantation). Median (range) radionucleotide GFR was 56.7ml/min/1.73m(2) (22.8-109.2ml/min/1.73m(2)). In the study cohort as a whole, the CKD-EPI creatinine-cystatin C combined equation showed the highest performance, but was only slightly superior to the CKD-EPI creatinine equation. However, in individuals with cystic fibrosis, low arm muscle mass and/or low body mass index, all of the creatinine-based equations showed unacceptable performance. In these subgroups, improved GFR estimation was seen with the CKD-EPI cystatin C equation, and predictions were better still using the CKD-EPI creatinine-cystatin C combined equation. This study shows adequate predictive ability of CKD-EPI creatinine in the cohort as a whole, but unacceptable performance in patients with cystic fibrosis, low arm muscle mass and/or low body mass index. Our findings demonstrate that cystatin C may be a preferable filtration marker in these subgroups. Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  18. Preliminary performance characterizations of an engineering model multipropellant resistojet for space station application

    NASA Technical Reports Server (NTRS)

    Morren, W. Earl; Hay, Stuart S.; Haag, Thomas W.; Sovey, James S.

    1987-01-01

    Presented are the results of a program to describe the operational characteristics of an engineering model multipropellant resistojet for application as an auxiliary propulsion system for the space station. Performance was measured on hydrogen, helium, methane, water (steam), nitrogen, air, argon, and carbon dioxide. Thrust levels ranged form 109 to 355 mN, power levels ranged from 167 to 506 W, and specific impulse values ranged from 93 to 385 sec, depending on the propellant, chamber pressure, and heater current level selected. Detailed thermal maps of the heater and heat exchanger were also obtained for operation with carbon dioxide.

  19. Preliminary performance characterizations of an engineering model multipropellant resistojet for space station application

    NASA Technical Reports Server (NTRS)

    Morren, W. Earl; Haag, Thomas W.; Sovey, James S.; Hay, Stuart S.

    1987-01-01

    Presented are the results of a program to describe the operational characteristics of an engineering model multipropellant resistojet for application as an auxiliary propulsion system for the space station. Performance was measured on hydrogen, helium, methane, water (steam), nitrogen, air, argon, and carbon dioxide. Thrust levels ranged from 109 to 355 mN, power levels ranged from 167 to 506 W, and specific impulse values ranged from 93 to 385 sec, depending on the propellant, chamber pressure, and heater current level selected. Detailed thermal maps of the heater and heat exchanger were also obtained for operation with carbon dioxide.

  20. Preliminary Transient Performance Data on the J73 Turbojet Engine. II - Altitude, 35,000 Feet

    NASA Technical Reports Server (NTRS)

    Lubick, Robert J.; Sobolewski, Adam E.

    1953-01-01

    A program was undertaken to determine the J73 turbojet engine compressor stall and surge characteristics and combustor blow-out limits encountered during transient engine operation. Data were obtained in the form of oscillograph traces showing the time history of several engine performance parameters with changes in engine fuel flow. The data presented in this report are for step changes in fuel flow at an altitude of 35,000 feet, at flight Mach numbers of 0.3, 0.8, and 1.2, and at several engine-inlet temperatures,

  1. Performance of an adaptive phase estimator for coherent free-space optical communications over Gamma-Gamma turbulence

    NASA Astrophysics Data System (ADS)

    Li, Yiming; Gao, Chao; Liang, Haodong; Miao, Maoke; Li, Xiaofeng

    2017-04-01

    This paper investigates an adaptive phase estimator for coherent free-space optical (FSO) communication systems. Closed-form solutions for variance of phase errors are derived when the optical beam is subjected to Gamma-Gamma distributed turbulence. The adaptive phase estimator has improved upon the phase error performance in comparison to conventional phase estimators. We also demonstrate notable improvement in BER performance when applying our adaptive phase estimator to coherent FSO communication systems.

  2. Influence of Ta content in high purity niobium on cavity performance: preliminary results

    SciTech Connect

    Carneiro, Tadeu; Klinkenberg, Christian; Kneisel, Peter; Myneni, Ganapati; Singer, Waldemar; Singer, Xenia; Proch, Dieter

    2004-08-01

    In a previous paper [1] a program for reducing the costs of high purity niobium was outlined. This program was based on the fact that niobium prices could be reduced, if a higher content of Ta, which does not significantly affect the RRR-value, could be tolerated for high performance cavities. This contribution reports on the execution of this program and its present status. Four ingots with different Ta contents have been melted and transformed into sheets. In each manufacturing step material quality has been monitored, using chemical analysis, thermal conductivity measurements and evaluation of mechanical properties. The niobium sheets have been scanned for defects by an eddy current device. Two single cell cavities (CEBAF geometry) have been fabricated from each of three ingots, with Ta concentrations of 150, 600 and 1300 wtppm. A series of tests have been performed on each cavity with increasing amount of material removal. This contribution reports on the test results and gives an analysis of the data.

  3. Evaluation of Exercise Tolerance in Dialysis Patients Performing Tai Chi Training: Preliminary Study

    PubMed Central

    Bulińska, Katarzyna; Kusztal, Mariusz; Kowalska, Joanna; Rogowski, Łukasz; Zembroń-Łacny, Agnieszka; Gołębiowski, Tomasz; Ochmann, Bartosz; Pawlaczyk, Weronika; Woźniewski, Marek

    2016-01-01

    Introduction. Patients with end-stage renal disease (ESRD) have poor physical performance and exercise capacity due to frequent dialysis treatments. Tai Chi exercises can be very useful in the area of rehabilitation of people with ESRD. Objectives. The aim of the study was to assess exercise capacity in ESRD patients participating in 6-month Tai Chi training. Patients and Methods. Twenty dialysis patients from Wroclaw took part in the training; at the end of the project, 14 patients remained (age 69.2 ± 8.6 years). A 6-minute walk test (6MWT) and spiroergometry were performed at the beginning and after 6 months of training. Results. After 6 months of Tai Chi, significant improvements were recorded in mean distance in the 6MWT (387.89 versus 436.36 m), rate of perceived exertion (7.4 versus 4.7), and spiroergometry (8.71 versus 10.08 min). Conclusions. In the ESRD patients taking part in Tai Chi training, a definite improvement in exercise tolerance was recorded after the 6-month training. Tai Chi exercises conducted on days without dialysis can be an effective and interesting form of rehabilitation for patients, offering them a chance for a better quality of life and fewer falls and hospitalisations that are the result of it. PMID:27547228

  4. A preliminary study of the performance and characteristics of a supersonic executive aircraft

    NASA Technical Reports Server (NTRS)

    Mascitti, V. R.

    1977-01-01

    The impact of advanced supersonic technologies on the performance and characteristics of a supersonic executive aircraft was studied in four configurations with different engine locations and wing/body blending and an advanced nonafterburning turbojet or variable cycle engine. An M 2.2 design Douglas scaled arrow-wing was used with Learjet 35 accommodations. All four configurations with turbojet engines meet the performance goals of 5926 km (3200 n.mi.) range, 1981 meters (6500 feet) takeoff field length, and 77 meters per second (150 knots) approach speed. The noise levels of of turbojet configurations studied are excessive. However, a turbojet with mechanical suppressor was not studied. The variable cycle engine configuration is deficient in range by 555 km (300 n.mi) but nearly meets subsonic noise rules (FAR 36 1977 edition), if coannular noise relief is assumed. All configurations are in the 33566 to 36287 kg (74,000 to 80,000 lbm) takeoff gross weight class when incorporating current titanium manufacturing technology.

  5. Preliminary performance and life evaluations of a 2-kW arcjet

    NASA Technical Reports Server (NTRS)

    Morren, W. Earl; Curran, Francis M.

    1991-01-01

    The first results of a program to expand the operational envelope of low-power arcjets to higher specific impulse and power levels are presented. The performance of a kW-class laboratory model arcjet thruster was characterized at three mass flow rates of a 2:1 mixture of hydrogen and nitrogen at power levels ranging from 1.0 to 2.0 kW. This same thruster was then operated for a total of 300 h at a specific impulse and power level of 550 s and 2.0 kW, respectively, in three continuous 100-h sessions. Thruster operation during the three test segments was stable, and no measurable performance degradation was observed during the test series. Substantial cathode erosion was observed during an inspection following the second 100-h test segment. Most notable was the migration of material from the center of the cathode tip to a ring around a large crater. The anode sustained no significant damage during the endurance test segments. Some difficulty was encountered during start-up after disassembly and inspection following the second 100-h test segment, which caused constrictor erosion. This resulted in a reduced flow restriction and arc chamber pressure, which in turn caused a reduction in the arc impedance.

  6. A new rapid molecular point-of-care assay for Trichomonas vaginalis: preliminary performance data.

    PubMed

    Pearce, David M; Styles, David N; Hardick, Justin P; Gaydos, Charlotte A

    2013-09-01

    Trichomonas vaginalis infection is the most prevalent treatable sexually transmitted infection (STI) in the world. An accurate point-of-care (PoC) molecular test would enable patients to be tested and treated for T vaginalis in a single visit to the genitourinary medicine clinic, community STI clinic, pharmacy or doctor's office. In this report, we describe a rapid prototype assay for T vaginalis designed for use in conjunction with the Atlas io PoC platform, and initial verification of its performance using 90 clinical samples. A rapid prototype T vaginalis assay was designed. The test, featuring novel electrochemical end-point detection, used a multi-copy region of the T vaginalis genome as the assay target. Ninety clinical vaginal swab samples were used to verify the performance of the prototype assay. The assay demonstrated a sensitivity and specificity of 95.5% (42/44) and 95.7% (44/46), respectively, when tested using clinical samples. Assay inclusivity was demonstrated for a number of geographically diverse T vaginalis isolates, and the test showed no cross-reactivity with either human DNA or a panel of DNAs isolated from common cross-reactants. The sensitivity and specificity achieved using this prototype assay is comparable with that achieved for existing central laboratory nucleic acid amplification tests used for screening patients for T vaginalis.

  7. A new rapid molecular point-of-care assay for Trichomonas vaginalis: preliminary performance data

    PubMed Central

    Pearce, David M; Styles, David N; Hardick, Justin P; Gaydos, Charlotte A

    2013-01-01

    Objective Trichomonas vaginalis infection is the most prevalent treatable sexually transmitted infection (STI) in the world. An accurate point-of-care (PoC) molecular test would enable patients to be tested and treated for T vaginalis in a single visit to the genitourinary medicine clinic, community STI clinic, pharmacy or doctor’s office. In this report, we describe a rapid prototype assay for T vaginalis designed for use in conjunction with the Atlas io PoC platform, and initial verification of its performance using 90 clinical samples. Methods A rapid prototype T vaginalis assay was designed. The test, featuring novel electrochemical endpoint detection, used a multi-copy region of the T vaginalis genome as the assay target. Ninety clinical vaginal swab samples were used to verify the performance of the prototype assay. Results The assay demonstrated a sensitivity and specificity of 95.5% (42/44) and 95.7% (44/46), respectively, when tested using clinical samples. Assay inclusivity was demonstrated for a number of geographically diverse T vaginalis isolates, and the test showed no cross-reactivity with either human DNA or a panel of DNAs isolated from common cross-reactants. Conclusions The sensitivity and specificity achieved using this prototype assay is comparable with that achieved for existing central laboratory nucleic acid amplification tests used for screening patients for T vaginalis. PMID:23605852

  8. A preliminary assessment of financial stability, efficiency, health systems and health outcomes using performance-based contracts in Belize.

    PubMed

    Bowser, Diana M; Figueroa, Ramon; Natiq, Laila; Okunogbe, Adeyemi

    2013-01-01

    Over the last 10 years, Belize has implemented a National Health Insurance (NHI) program that uses performance-based contracts with both public and private facilities to improve financial sustainability, efficiency and service provision. Data were collected at the facility, district and national levels in order to assess trends in financial sustainability, efficiency payments, year-end bonuses and health system and health outcomes. A difference-in-difference approach was used to assess the difference in technical efficiency between private and public facilities. The results show that per capita spending on services provided by the NHI program has decreased over the period 2006-2009 from BZ$177 to BZ$136. The private sector has achieved higher levels of technical efficiency, but lower percentages of efficiency and year-end bonus payments. Districts with contracts through the NHI program showed greater improvements in facility births, nurse density, reducing maternal mortality, diabetes deaths and morbidity from bronchitis, emphysema and asthma than districts without contracts over the period 2006-2010. This preliminary assessment of Belize's pay-for-performance system provides some positive results, however further research is needed to use the lessons learned from Belize to implement similar reforms in other systems.

  9. A Preliminary Model for Spacecraft Propulsion Performance Analysis Based on Nuclear Gain and Subsystem Mass-Power Balances

    NASA Technical Reports Server (NTRS)

    Chakrabarti, Suman; Schmidt, George R.; Thio, Y. C.; Hurst, Chantelle M.

    1999-01-01

    A preliminary model for spacecraft propulsion performance analysis based on nuclear gain and subsystem mass-power balances are presented in viewgraph form. For very fast missions with straight-line trajectories, it has been shown that mission trip time is proportional to the cube root of alpha. Analysis of spacecraft power systems via a power balance and examination of gain vs. mass-power ratio has shown: 1) A minimum gain is needed to have enough power for thruster and driver operation; and 2) Increases in gain result in decreases in overall mass-power ratio, which in turn leads to greater achievable accelerations. However, subsystem mass-power ratios and efficiencies are crucial: less efficient values for these can partially offset the effect of nuclear gain. Therefore, it is of interest to monitor the progress of gain-limited subsystem technologies and it is also possible that power-limited systems with sufficiently low alpha may be competitive for such ambitious missions. Topics include Space flight requirements; Spacecraft energy gain; Control theory for performance; Mission assumptions; Round trips: Time and distance; Trip times; Vehicle acceleration; and Minimizing trip times.

  10. Rocket Based Combined Cycle Exchange Inlet Performance Estimation at Supersonic Speeds

    NASA Astrophysics Data System (ADS)

    Murzionak, Aliaksandr

    A method to estimate the performance of an exchange inlet for a Rocket Based Combined Cycle engine is developed. This method is to be used for exchange inlet geometry optimization and as such should be able to predict properties that can be used in the design process within a reasonable amount of time to allow multiple configurations to be evaluated. The method is based on a curve fit of the shocks developed around the major components of the inlet using solutions for shocks around sharp cones and 2D estimations of the shocks around wedges with blunt leading edges. The total pressure drop across the estimated shocks as well as the mass flow rate through the exchange inlet are calculated. The estimations for a selected range of free-stream Mach numbers between 1.1 and 7 are compared against numerical finite volume method simulations which were performed using available commercial software (Ansys-CFX). The total pressure difference between the two methods is within 10% for the tested Mach numbers of 5 and below, while for the Mach 7 test case the difference is 30%. The mass flow rate on average differs by less than 5% for all tested cases with the maximum difference not exceeding 10%. The estimation method takes less than 3 seconds on 3.0 GHz single core processor to complete the calculations for a single flight condition as oppose to over 5 days on 8 cores at 2.4 GHz system while using 3D finite volume method simulation with 1.5 million elements mesh. This makes the estimation method suitable for the use with exchange inlet geometry optimization algorithm.

  11. Preliminary Evaluation of Visual and Flight Performance of Three Current Multifocal Contact Lens Designs for Presbyopic US Army Aviators

    DTIC Science & Technology

    2005-01-01

    AriyU S" ~Aircrew Health and Performance Division:...• Approved for public release, distribution unlimited Laboator Notice Qualified requesters...DOCUMENTATION PAGE 1 Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average I hour per response...SUPPLEMENTARY NOTES 12a. DISTRIBUTION / AVAILABILITY STATEMENT Approved for public release, distribution unlimited 20050210 084 13. ABSTRACT (Maximum

  12. Design and Preliminary Thermal Performance of the Mars Science Laboratory Rover Heat Exchangers

    NASA Technical Reports Server (NTRS)

    Mastropietro, A. J.; Beatty, John; Kelly, Frank; Birur, Gajanana; Bhandari, Pradeep; Pauken, Michael; Illsley, Peter; Liu, Yuanming; Bame, David; Miller, Jennifer

    2010-01-01

    The challenging range of proposed landing sites for the Mars Science Laboratory Rover requires a rover thermal management system that is capable of keeping temperatures controlled across a wide variety of environmental conditions. On the Martian surface where temperatures can be as cold as -123 degrees Centigrade and as warm as 38 degrees Centigrade, the Rover relies upon a Mechanically Pumped Fluid Loop (MPFL) and external radiators to maintain the temperature of sensitive electronics and science instruments within a -40 degrees Centigrade to 50 degrees Centigrade range. The MPFL also manages significant waste heat generated from the Rover power source, known as the Multi Mission Radioisotope Thermoelectric Generator (MMRTG). The MMRTG produces 110 Watts of electrical power while generating waste heat equivalent to approximately 2000 Watts. Two similar Heat Exchanger (HX) assemblies were designed to both acquire the heat from the MMRTG and radiate waste heat from the onboard electronics to the surrounding Martian environment. Heat acquisition is accomplished on the interior surface of each HX while heat rejection is accomplished on the exterior surface of each HX. Since these two surfaces need to be at very different temperatures in order for the MPFL to perform efficiently, they need to be thermally isolated from one another. The HXs were therefore designed for high in-plane thermal conductivity and extremely low through-thickness thermal conductivity by using aerogel as an insulator inside composite honeycomb sandwich panels. A complex assembly of hand welded and uniquely bent aluminum tubes are bonded onto the HX panels and were specifically designed to be easily mated and demated to the rest of the Rover Heat Recovery and Rejection System (RHRS) in order to ease the integration effort. During the cruise phase to Mars, the HX assemblies serve the additional function of transferring heat from the Rover MPFL to the separate Cruise Stage MPFL so that heat

  13. Design and Preliminary Thermal Performance of the Mars Science Laboratory Rover Heat Exchangers

    NASA Technical Reports Server (NTRS)

    Mastropietro, A. J.; Beatty, John; Kelly, Frank; Birur, Gajanana; Bhandari, Pradeep; Pauken, Michael; Illsley, Peter; Liu, Yuanming; Bame, David; Miller, Jennifer

    2010-01-01

    The challenging range of proposed landing sites for the Mars Science Laboratory Rover requires a rover thermal management system that is capable of keeping temperatures controlled across a wide variety of environmental conditions. On the Martian surface where temperatures can be as cold as -123 degrees Centigrade and as warm as 38 degrees Centigrade, the Rover relies upon a Mechanically Pumped Fluid Loop (MPFL) and external radiators to maintain the temperature of sensitive electronics and science instruments within a -40 degrees Centigrade to 50 degrees Centigrade range. The MPFL also manages significant waste heat generated from the Rover power source, known as the Multi Mission Radioisotope Thermoelectric Generator (MMRTG). The MMRTG produces 110 Watts of electrical power while generating waste heat equivalent to approximately 2000 Watts. Two similar Heat Exchanger (HX) assemblies were designed to both acquire the heat from the MMRTG and radiate waste heat from the onboard electronics to the surrounding Martian environment. Heat acquisition is accomplished on the interior surface of each HX while heat rejection is accomplished on the exterior surface of each HX. Since these two surfaces need to be at very different temperatures in order for the MPFL to perform efficiently, they need to be thermally isolated from one another. The HXs were therefore designed for high in-plane thermal conductivity and extremely low through-thickness thermal conductivity by using aerogel as an insulator inside composite honeycomb sandwich panels. A complex assembly of hand welded and uniquely bent aluminum tubes are bonded onto the HX panels and were specifically designed to be easily mated and demated to the rest of the Rover Heat Recovery and Rejection System (RHRS) in order to ease the integration effort. During the cruise phase to Mars, the HX assemblies serve the additional function of transferring heat from the Rover MPFL to the separate Cruise Stage MPFL so that heat

  14. Channel Estimation and Performance Analysis of One-Bit Massive MIMO Systems

    NASA Astrophysics Data System (ADS)

    Li, Yongzhi; Tao, Cheng; Seco-Granados, Gonzalo; Mezghani, Amine; Swindlehurst, A. Lee; Liu, Liu

    2017-08-01

    This paper considers channel estimation and system performance for the uplink of a single-cell massive multiple-input multiple-output (MIMO) system. Each receive antenna of the base station (BS) is assumed to be equipped with a pair of one-bit analog-to-digital converters (ADCs) to quantize the real and imaginary part of the received signal. We first propose an approach for channel estimation that is applicable for both flat and frequency-selective fading, based on the Bussgang decomposition that reformulates the nonlinear quantizer as a linear functionwith identical first- and second-order statistics. The resulting channel estimator outperforms previously proposed approaches across all SNRs. We then derive closed-form expressions for the achievable rate in flat fading channels assuming low SNR and a large number of users for the maximal ratio and zero forcing receivers that takes channel estimation error due to both noise and one-bit quantization into account. The closed-form expressions in turn allow us to obtain insight into important system design issues such as optimal resource allocation, maximal sum spectral efficiency, overall energy efficiency, and number of antennas. Numerical results are presented to verify our analytical results and demonstrate the benefit of optimizing system performance accordingly.

  15. Analytical performance evaluation of SAR ATR with inaccurate or estimated models

    NASA Astrophysics Data System (ADS)

    DeVore, Michael D.

    2004-09-01

    Hypothesis testing algorithms for automatic target recognition (ATR) are often formulated in terms of some assumed distribution family. The parameter values corresponding to a particular target class together with the distribution family constitute a model for the target's signature. In practice such models exhibit inaccuracy because of incorrect assumptions about the distribution family and/or because of errors in the assumed parameter values, which are often determined experimentally. Model inaccuracy can have a significant impact on performance predictions for target recognition systems. Such inaccuracy often causes model-based predictions that ignore the difference between assumed and actual distributions to be overly optimistic. This paper reports on research to quantify the effect of inaccurate models on performance prediction and to estimate the effect using only trained parameters. We demonstrate that for large observation vectors the class-conditional probabilities of error can be expressed as a simple function of the difference between two relative entropies. These relative entropies quantify the discrepancies between the actual and assumed distributions and can be used to express the difference between actual and predicted error rates. Focusing on the problem of ATR from synthetic aperture radar (SAR) imagery, we present estimators of the probabilities of error in both ideal and plug-in tests expressed in terms of the trained model parameters. These estimators are defined in terms of unbiased estimates for the first two moments of the sample statistic. We present an analytical treatment of these results and include demonstrations from simulated radar data.

  16. Methods to assess performance of models estimating risk of death in intensive care patients: a review.

    PubMed

    Cook, D A

    2006-04-01

    Models that estimate the probability of death of intensive care unit patients can be used to stratify patients according to the severity of their condition and to control for casemix and severity of illness. These models have been used for risk adjustment in quality monitoring, administration, management and research and as an aid to clinical decision making. Models such as the Mortality Prediction Model family, SAPS II, APACHE II, APACHE III and the organ system failure models provide estimates of the probability of in-hospital death of ICU patients. This review examines methods to assess the performance of these models. The key attributes of a model are discrimination (the accuracy of the ranking in order of probability of death) and calibration (the extent to which the model's prediction of probability of death reflects the true risk of death). These attributes should be assessed in existing models that predict the probability of patient mortality, and in any subsequent model that is developed for the purposes of estimating these probabilities. The literature contains a range of approaches for assessment which are reviewed and a survey of the methodologies used in studies of intensive care mortality models is presented. The systematic approach used by Standards for Reporting Diagnostic Accuracy provides a framework to incorporate these theoretical considerations of model assessment and recommendations are made for evaluation and presentation of the performance of models that estimate the probability of death of intensive care patients.

  17. Semi-supervised multimodal relevance vector regression improves cognitive performance estimation from imaging and biological biomarkers.

    PubMed

    Cheng, Bo; Zhang, Daoqiang; Chen, Songcan; Kaufer, Daniel I; Shen, Dinggang

    2013-07-01

    Accurate estimation of cognitive scores for patients can help track the progress of neurological diseases. In this paper, we present a novel semi-supervised multimodal relevance vector regression (SM-RVR) method for predicting clinical scores of neurological diseases from multimodal imaging and biological biomarker, to help evaluate pathological stage and predict progression of diseases, e.g., Alzheimer's diseases (AD). Unlike most existing methods, we predict clinical scores from multimodal (imaging and biological) biomarkers, including MRI, FDG-PET, and CSF. Considering that the clinical scores of mild cognitive impairment (MCI) subjects are often less stable compared to those of AD and normal control (NC) subjects due to the heterogeneity of MCI, we use only the multimodal data of MCI subjects, but no corresponding clinical scores, to train a semi-supervised model for enhancing the estimation of clinical scores for AD and NC subjects. We also develop a new strategy for selecting the most informative MCI subjects. We evaluate the performance of our approach on 202 subjects with all three modalities of data (MRI, FDG-PET and CSF) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. The experimental results show that our SM-RVR method achieves a root-mean-square error (RMSE) of 1.91 and a correlation coefficient (CORR) of 0.80 for estimating the MMSE scores, and also a RMSE of 4.45 and a CORR of 0.78 for estimating the ADAS-Cog scores, demonstrating very promising performances in AD studies.

  18. On the estimation algorithm for adaptive performance optimization of turbofan engines

    NASA Technical Reports Server (NTRS)

    Espana, Martin D.

    1993-01-01

    The performance seeking control (PSC) algorithm is designed to continuously optimize the performance of propulsion systems. The PSC algorithm uses a nominal propulsion system model and estimates, in flight, the engine deviation parameters (EDPs) characterizing the engine deviations with respect to nominal conditions. In practice, because of measurement biases and/or model uncertainties, the estimated EDPs may not reflect the engine's actual off-nominal condition. This factor has a direct impact on the PSC scheme exacerbated by the open-loop character of the algorithm. In this paper, the effects produced by unknown measurement biases over the estimation algorithm are evaluated. This evaluation allows for identification of the most critical measurements for application of the PSC algorithm to an F100 engine. An equivalence relation between the biases and EDPs stems from the analysis; therefore, it is undecided whether the estimated EDPs represent the actual engine deviation or whether they simply reflect the measurement biases. A new algorithm, based on the engine's (steady-state) optimization model, is proposed and tested with flight data. When compared with previous Kalman filter schemes, based on local engine dynamic models, the new algorithm is easier to design and tune and it reduces the computational burden of the onboard computer.

  19. Preliminary performance of the MKII 17 GHz traveling wave relativistic klystron

    SciTech Connect

    Haimson, J.; Mecklenburg, B.; Stowell, G.; Kreischer, K.E.; Mastovsky, I.

    1999-05-01

    Initial test results are presented of an upgraded RF source developed for high peak power 17 GHz linear accelerator applications. The objectives of this upgrade program were (a) to increase the output capability of the existing vacuum demountable prototype tube so that RF power could also be supplied to a future 2 MeV photoinjector system without appreciable loss of input power to the 17 GHz linac and (b) to investigate the performance of a new design traveling wave output circuit incorporating a racetrack shaped dual output coupler with 5{percent} bandwidth high peak power ceramic RF windows. These recently installed devices are presently being conditioned and tested at the MIT Plasma Science and Fusion Center. {copyright} {ital 1999 American Institute of Physics.}

  20. Preliminary performance of the MKII 17 GHz traveling wave relativistic klystron

    SciTech Connect

    Haimson, J.; Mecklenburg, B.; Stowell, G.; Kreischer, K. E.; Mastovsky, I.

    1999-05-07

    Initial test results are presented of an upgraded RF source developed for high peak power 17 GHz linear accelerator applications. The objectives of this upgrade program were (a) to increase the output capability of the existing vacuum demountable prototype tube so that RF power could also be supplied to a future 2 MeV photoinjector system without appreciable loss of input power to the 17 GHz linac and (b) to investigate the performance of a new design traveling wave output circuit incorporating a racetrack shaped dual output coupler with 5% bandwidth high peak power ceramic RF windows. These recently installed devices are presently being conditioned and tested at the MIT Plasma Science and Fusion Center.

  1. Interactive segmentation of plexiform neurofibroma tissue: method and preliminary performance evaluation.

    PubMed

    Weizman, Lior; Hoch, Lior; Ben Bashat, Dafna; Joskowicz, Leo; Pratt, Li-tal; Constantini, Shlomi; Ben Sira, Liat

    2012-08-01

    Plexiform neurofibromas (PNs) are a major manifestation of neurofibromatosis-1 (NF1), a common genetic disease involving the nervous system. Treatment decisions are mostly based on a gross assessment of changes in tumor using MRI. Accurate volumetric measurements are rarely performed in this kind of tumors mainly due to its great dispersion, size, and multiple locations. This paper presents a semi-automatic method for segmentation of PN from STIR MRI scans. The method starts with a user-based delineation of the tumor area in a single slice and automatically segments the PN lesions in the entire image based on the tumor connectivity. Experimental results on seven datasets, with lesion volumes in the range of 75-690 ml, yielded a mean absolute volume error of 10 % (after manual adjustment) as compared to manual segmentation by an expert radiologist. The mean computation and interaction time was 13 versus 63 min for manual annotation.

  2. Preliminary results on performance testing of a turbocharged rotary combustion engine

    NASA Technical Reports Server (NTRS)

    Meng, P. R.; Rice, W. J.; Schock, H. J.; Pringle, D. P.

    1982-01-01

    The performance of a turbocharged rotary engine at power levels above 75 kW (100 hp) was studied. A twin rotor turbocharged Mazda engine was tested at speeds of 3000 to 6000 rpm and boost pressures to 7 psi. The NASA developed combustion diagnostic instrumentation was used to quantify indicated and pumping mean effect pressures, peak pressure, and face to face variability on a cycle by cycle basis. Results of this testing showed that a 5900 rpm a 36 percent increase in power was obtained by operating the engine in the turbocharged configuration. When operating with lean carburetor jets at 105 hp (78.3 kW) and 4000 rpm, a brake specific fuel consumption of 0.45 lbm/lb-hr was measured.

  3. Performance bounds on micro-Doppler estimation and adaptive waveform design using OFDM signals

    NASA Astrophysics Data System (ADS)

    Sen, Satyabrata; Barhen, Jacob; Glover, Charles W.

    2014-05-01

    We analyze the performance of a wideband orthogonal frequency division multiplexing (OFDM) signal in estimating the micro-Doppler frequency of a target having multiple rotating scatterers (e.g., rotor blades of a helicopter, propellers of a submarine). The presence of rotating scatterers introduces Doppler frequency modulation in the received signal by generating sidebands about the transmitted frequencies. This is called the micro-Doppler effects. The use of a frequency-diverse OFDM signal in this context enables us to independently analyze the micro-Doppler characteristics with respect to a set of orthogonal subcarrier frequencies. Therefore, to characterize the accuracy of micro-Doppler frequency estimation, we compute the Craḿer-Rao Bound (CRB) on the angular-velocity estimate of the target while considering the scatterer responses as deterministic but unknown nuisance parameters. Additionally, to improve the accuracy of the estimation procedure, we formulate and solve an optimization problem by minimizing the CRB on the angular-velocity estimate with respect to the transmitting OFDM spectral coefficients. We present several numerical examples to demonstrate the CRB variations at different values of the signal-to-noise ratio (SNR) and the number of OFDM subcarriers. The CRB values not only decrease with the increase in the SNR values, but also reduce as we increase the number of subcarriers implying the significance of frequency-diverse OFDM waveforms. The improvement in estimation accuracy due to the adaptive waveform design is also numerically analyzed. Interestingly, we find that the relative decrease in the CRBs on the angular-velocity estimate is more pronounced for larger number of OFDM subcarriers.

  4. Performance of velocity vector estimation using an improved dynamic beamforming setup

    NASA Astrophysics Data System (ADS)

    Munk, Peter; Jensen, Joergen A.

    2001-05-01

    Estimation of velocity vectors using transverse spatial modulation has previously been presented. Initially, the velocity estimation was improved using an approximated dynamic beamformer setup instead of a static combined with a new velocity estimation scheme. A new beamformer setup for dynamic control of the acoustic field, based on the Pulsed Plane Wave Decomposition (PPWD), is presented. The PPWD gives an unambiguous relation between a given acoustic field and the time functions needed on an array transducer for transmission. Applying this method for the receive beamformation results in a setup of the beamformer with different filters for each channel for each estimation depth. The method of the PPWD is illustrated by analytical expressions of the decomposed acoustic field and these results are used for simulation. Results of velocity estimates using the new setup are given on the basis of simulated and experimental data. The simulation setup is an attempt to approximate the situation present when performing a scanning of the carotid artery with a linear array. Measurement of the flow perpendicular to the emission direction is possible using the approach of transverse spatial modulation. This is most often the case in a scanning of the carotid artery, where the situation is handled by an angled Doppler setup in the present ultrasound scanners. The modulation period of 2 mm is controlled for a range of 20-40 mm which covers the typical range of the carotid artery. A 6 MHz array on a 128-channel system is simulated. The flow setup in the simulation is based on a vessel with a parabolic flow profile for a 60 and 90-degree flow angle. The experimental results are based on the backscattered signal from a sponge mounted in a stepping device. The bias and std. Dev. Of the velocity estimate are calculated for four different flow angles (50,60,75 and 90 degrees). The velocity vector is calculated using the improved 2D estimation approach at a range of depths.

  5. Performance Bounds on Micro-Doppler Estimation and Adaptive Waveform Design Using OFDM Signals

    SciTech Connect

    Sen, Satyabrata; Barhen, Jacob; Glover, Charles Wayne

    2014-01-01

    We analyze the performance of a wideband orthogonal frequency division multiplexing (OFDM) signal in estimating the micro-Doppler frequency of a target having multiple rotating scatterers (e.g., rotor blades of a helicopter, propellers of a submarine). The presence of rotating scatterers introduces Doppler frequency modulation in the received signal by generating sidebands about the transmitted frequencies. This is called the micro-Doppler effects. The use of a frequency-diverse OFDM signal in this context enables us to independently analyze the micro-Doppler characteristics with respect to a set of orthogonal subcarrier frequencies. Therefore, to characterize the accuracy of micro-Doppler frequency estimation, we compute the Cram er-Rao Bound (CRB) on the angular-velocity estimate of the target while considering the scatterer responses as deterministic but unknown nuisance parameters. Additionally, to improve the accuracy of the estimation procedure, we formulate and solve an optimization problem by minimizing the CRB on the angular-velocity estimate with respect to the transmitting OFDM spectral coefficients. We present several numerical examples to demonstrate the CRB variations at different values of the signal-to-noise ratio (SNR) and the number of OFDM subcarriers. The CRB values not only decrease with the increase in the SNR values, but also reduce as we increase the number of subcarriers implying the significance of frequency-diverse OFDM waveforms. The improvement in estimation accuracy due to the adaptive waveform design is also numerically analyzed. Interestingly, we find that the relative decrease in the CRBs on the angular-velocity estimate is more pronounced for larger number of OFDM subcarriers.

  6. Neuropsychological assessment and telemedicine: a preliminary study examining the reliability of neuropsychology services performed via telecommunication.

    PubMed

    Jacobsen, Svenn E; Sprenger, Terje; Andersson, Stein; Krogstad, Jan-Magne

    2003-03-01

    Within the last decade, various applications of two-way audio-visual telecommunication have been implemented in the Norwegian health care system to facilitate the delivery of medical services to patients located in rural areas away from the hospitals. This technology may also be useful to extend neuropsychological services to underserved areas and thereby reduce the patients' travel time and costs. In the current study, a total of 12 visual, verbal and performance tests were administered face-to-face and via videophones to 32 volunteer participants to examine the consistency and stability of test-scores when delivered via different formats. The obtained reliability coefficients ranged from .37 to .86 with a median value of .74. When testing for mean differences, the measures on verbal learning (WMS-Logical Memory I) and auditory attention (Seashore Rhythm Test) differed significantly due to administration format (t = 2.34, p = .024 and t = 2.37, p = .025, respectively). The findings imply that administration format does not appear to affect the reliability of measurement but neuropsychological test performance is significantly higher for the measures of attention and memory when delivered via videophone. Additional research on these cognitive domains is required, and if the observed differences due to testing format persist, separate normative data via telecommunication will be required before assessments are carried out. Also, since only normal participants were included in this study, the findings may have external validity for normal populations, but similar controlled trials with patients need to be completed before remote assessments can be implemented in regular clinical practice.

  7. A two-colored chewing gum test for assessing masticatory performance: a preliminary study.

    PubMed

    Endo, Toshiya; Komatsuzaki, Akira; Kurokawa, Hiroomi; Tanaka, Satoshi; Kobayashi, Yoshiki; Kojima, Koji

    2014-01-01

    This study was conducted to compare subjective and objective assessment methods of a two-colored chewing gum test and to find out whether these methods are capable of discriminating masticatory performances between sexes. 31 adults, 16 males and 15 females participated in this study. Each subject chewed five samples of two-colored chewing gum sticks for 5, 10, 20, 30 and 50 chewing strokes, respectively. The subjective color-mixing and shape indices for the gum bolus (SCMI-B, SSI-B) and the subjective color-mixing index and objective color-mixing ratio for the gum wafer (SCMI-W, OCMR-W) were evaluated by two independent examiners and, on a different day, re-evaluated by one of the examiners. The SCMI-B and SCMI-W assessments had inter- and intra-examiner reliable agreement at 20 or more chewing strokes. The OCMR-W measurement demonstrated high accuracy and low reproducibility between and within the examiners. There were significant gender differences in the distribution of SCMI-W scores (P = 0.044) and in the mean OCMI-W (P = 0.007). The SCMI-B and SCMI-W assessments and the OCMR-W measurement were reliable and valid at the 20 and 30 chewing strokes in this two-colored chewing gum test. The subjective color-mixing index (SCMI-W) and objective color-mixing ratio (OCMR-W) for the chewing gum wafer are capable of discriminating masticatory performance between sexes in this two-colored chewing gum test and that the OCMR-W measurement is discriminating better than the SCMI-W assessment.

  8. Performance of default risk model with barrier option framework and maximum likelihood estimation: Evidence from Taiwan

    NASA Astrophysics Data System (ADS)

    Chou, Heng-Chih; Wang, David

    2007-11-01

    We investigate the performance of a default risk model based on the barrier option framework with maximum likelihood estimation. We provide empirical validation of the model by showing that implied default barriers are statistically significant for a sample of construction firms in Taiwan over the period 1994-2004. We find that our model dominates the commonly adopted models, Merton model, Z-score model and ZETA model. Moreover, we test the n-year-ahead prediction performance of the model and find evidence that the prediction accuracy of the model improves as the forecast horizon decreases. Finally, we assess the effect of estimated default risk on equity returns and find that default risk is able to explain equity returns and that default risk is a variable worth considering in asset-pricing tests, above and beyond size and book-to-market.

  9. Integrated State Estimation and Contingency Analysis Software Implementation using High Performance Computing Techniques

    SciTech Connect

    Chen, Yousu; Glaesemann, Kurt R.; Rice, Mark J.; Huang, Zhenyu

    2015-12-31

    Power system simulation tools are traditionally developed in sequential mode and codes are optimized for single core computing only. However, the increasing complexity in the power grid models requires more intensive computation. The traditional simulation tools will soon not be able to meet the grid operation requirements. Therefore, power system simulation tools need to evolve accordingly to provide faster and better results for grid operations. This paper presents an integrated state estimation and contingency analysis software implementation using high performance computing techniques. The software is able to solve large size state estimation problems within one second and achieve a near-linear speedup of 9,800 with 10,000 cores for contingency analysis application. The performance evaluation is presented to show its effectiveness.

  10. Preliminary Results of an Altitude-Wind-Tunnel Investigation of an Axial-Flow Gas Turbine-Propeller Engine. 1; Performance Characteristics

    NASA Technical Reports Server (NTRS)

    Saari, Martin J.; Wallner, Lewis E.

    1948-01-01

    A preliminary investigation of an axial-flow gas turbine-propeller engine was conduxted. Performance data were obtained for engine speeds from 8000 to 13,000 rpm and altitudes from 5000 to 35,000 feet and compressor inlet ram pressure ratios from 1.00 to 1.17.

  11. Estimate of Technical Potential for Minimum Efficiency Performance Standards in 13 Major World Economies

    SciTech Connect

    Letschert, Virginie; Desroches, Louis-Benoit; Ke, Jing; McNeil, Michael

    2012-07-01

    As part of the ongoing effort to estimate the foreseeable impacts of aggressive minimum efficiency performance standards (MEPS) programs in the world’s major economies, Lawrence Berkeley National Laboratory (LBNL) has developed a scenario to analyze the technical potential of MEPS in 13 major economies around the world1 . The “best available technology” (BAT) scenario seeks to determine the maximum potential savings that would result from diffusion of the most efficient available technologies in these major economies.

  12. A preliminary estimation of motorcyclist fatal injury risk by BAC level relative to car/van drivers.

    PubMed

    Keall, Michael D; Clark, Belinda; Rudin-Brown, Christina M

    2013-01-01

    This study sought to quantify the fatal injury risks for motorcyclists associated with the riders' blood alcohol concentrations (BACs). Using a case-control study design with New Zealand data, fatal injury risk curves for motorcyclists and car drivers were modeled. A total of 142 fatally injured drivers/riders (cases) and 58,000 control drivers/riders were studied. For motorcyclists, there were 13 cases and 194 controls. The rate of increase in fatal injury risk with increasing BAC was not found to be different for motorcyclists compared to car/van drivers. However, because the baseline risk for motorcyclists was already considerably higher than for car/van drivers, even modest amounts of alcohol were associated with very high risks for motorcyclists compared to sober car/van drivers. It was estimated that, relative to their sober risk, motorcycle riders at BAC = 0.03 percent have 3 times the fatality risk (95% confidence interval [CI] = 2.8-3.5) and, at BAC = 0.08, 20 times the fatality risk (95% CI = 15.0-27.3). Interventions focused on reducing the alcohol consumption of motorcycle riders are clearly required when the degree of risk even at low alcohol levels is as disturbingly high as estimated in the current study.

  13. Four hundred or more participants needed for stable contingency table estimates of clinical prediction rule performance.

    PubMed

    Kent, Peter; Boyle, Eleanor; Keating, Jennifer L; Albert, Hanne B; Hartvigsen, Jan

    2017-02-01

    To quantify variability in the results of statistical analyses based on contingency tables and discuss the implications for the choice of sample size for studies that derive clinical prediction rules. An analysis of three pre-existing sets of large cohort data (n = 4,062-8,674) was performed. In each data set, repeated random sampling of various sample sizes, from n = 100 up to n = 2,000, was performed 100 times at each sample size and the variability in estimates of sensitivity, specificity, positive and negative likelihood ratios, posttest probabilities, odds ratios, and risk/prevalence ratios for each sample size was calculated. There were very wide, and statistically significant, differences in estimates derived from contingency tables from the same data set when calculated in sample sizes below 400 people, and typically, this variability stabilized in samples of 400-600 people. Although estimates of prevalence also varied significantly in samples below 600 people, that relationship only explains a small component of the variability in these statistical parameters. To reduce sample-specific variability, contingency tables should consist of 400 participants or more when used to derive clinical prediction rules or test their performance. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Performance of principal scores to estimate the marginal compliers causal effect of an intervention.

    PubMed

    Porcher, Raphaël; Leyrat, Clémence; Baron, Gabriel; Giraudeau, Bruno; Boutron, Isabelle

    2016-02-28

    We examine the properties of principal scores methods to estimate the causal marginal odds ratio of an intervention for compliers in the context of a randomized controlled trial with non-compliers. The two-stage estimation approach has been proposed for a linear model by Jo and Stuart (Statistics in Medicine 2009; 28:2857-2875) under a principal ignorability (PI) assumption. Using a Monte Carlo simulation study, we compared the performance of several strategies to build and use principal score models and the robustness of the method to violations of underlying assumptions, in particular PI. Results showed that the principal score approach yielded unbiased estimates of the causal marginal log odds ratio under PI but that the method was sensitive to violations of PI, which occurs in particular when confounders are omitted from the analysis. For principal score analysis, probability weighting performed slightly better than full matching or 1:1 matching. Concerning the variables to be included in principal score models, the lowest mean squared error was generally obtained when using the true confounders. Using variables associated with the outcome only but not compliance however yielded very similar performance.

  15. Identifying dynamic characteristics of structures to estimate the performance of a smart wireless MA system

    NASA Astrophysics Data System (ADS)

    Heo, Gwanghee; Lee, WooSang; Lee, Giu; Lee, Donggi

    2005-05-01

    In this paper, a smart wireless MEMS-based accelerometer(MA) system has been designed and experimented for smart monitoring system of civil structures. In order to estimate the performance of a smart wireless MA system(SWMAS), dynamic characteristics of our model structure need to be identified. This system thus employed a high-performance AVR microcontroller, a wireless modem, and MA for multiplex communication capability and real time duplex communication. Various performance and experimental tests have been carried out to evaluate whether this system is suitable for monitoring system of civil structures. First, we examined its sensitivity, resolution, and noise, specifically to evaluate the performance of the smart wireless MA system. The results of experiments enabled us to estimate performance of the MA in SWMAS in comparison to the value of data sheet from MA. Second, characteristics of model structure were analyzed by the ambient vibration test based on the NExT combined with ERA. Finally, this analysis was compared to the one that was made by FE results, and the comparison proved that a smart wireless MA system was fitted in smart monitoring system effectively.

  16. Preparation and Preliminary Dialysis Performance Research of Polyvinylidene Fluoride Hollow Fiber Membranes

    PubMed Central

    Zhang, Qinglei; Lu, Xiaolong; Liu, Juanjuan; Zhao, Lihua

    2015-01-01

    In this study, the separation properties of Polyvinylidene fluoride (PVDF) hollow fiber hemodialysis membranes were improved by optimizing membrane morphology and structure. The results showed that the PVDF membrane had better mechanical and separation properties than Fresenius Polysulfone High-Flux (F60S) membrane. The PVDF membrane tensile stress at break, tensile elongation and bursting pressure were 11.3 MPa, 395% and 0.625 MPa, respectively. Ultrafiltration (UF) flux of pure water reached 108.2 L∙h−1∙m−2 and rejection of Albumin from bovine serum was 82.3%. The PVDF dialyzers were prepared by centrifugal casting. The influences of membrane area and simulate fluid flow rate on dialysis performance were investigated. The results showed that the clearance rate of urea and Lysozyme (LZM) were improved with increasing membrane area and fluid flow rate while the rejection of albumin from bovine serum (BSA) had little influence. The high-flux PVDF dialyzer UF coefficient reached 62.6 mL/h/mmHg. The PVDF dialyzer with membrane area 0.69 m2 has the highest clearance rate to LZM and urea. The clearance rate of LZM was 66.8% and urea was 87.7%. PMID:25807890

  17. Preparation and preliminary dialysis performance research of polyvinylidene fluoride hollow fiber membranes.

    PubMed

    Zhang, Qinglei; Lu, Xiaolong; Liu, Juanjuan; Zhao, Lihua

    2015-03-19

    In this study, the separation properties of Polyvinylidene fluoride (PVDF) hollow fiber hemodialysis membranes were improved by optimizing membrane morphology and structure. The results showed that the PVDF membrane had better mechanical and separation properties than Fresenius Polysulfone High-Flux (F60S) membrane. The PVDF membrane tensile stress at break, tensile elongation and bursting pressure were 11.3 MPa, 395% and 0.625 MPa, respectively. Ultrafiltration (UF) flux of pure water reached 108.2 L∙h-1∙m-2 and rejection of Albumin from bovine serum was 82.3%. The PVDF dialyzers were prepared by centrifugal casting. The influences of membrane area and simulate fluid flow rate on dialysis performance were investigated. The results showed that the clearance rate of urea and Lysozyme (LZM) were improved with increasing membrane area and fluid flow rate while the rejection of albumin from bovine serum (BSA) had little influence. The high-flux PVDF dialyzer UF coefficient reached 62.6 mL/h/mmHg. The PVDF dialyzer with membrane area 0.69 m2 has the highest clearance rate to LZM and urea. The clearance rate of LZM was 66.8% and urea was 87.7%.

  18. Preliminary evaluation of SensHand V1 in assessing motor skills performance in Parkinson disease.

    PubMed

    Cavallo, Filippo; Esposito, Dario; Rovini, Erika; Aquilano, Michela; Carrozza, Maria Chiara; Dario, Paolo; Maremmani, Carlo; Bongioanni, Paolo

    2013-06-01

    Nowadays, the increasing old population 65+ as well as the pace imposed by work activities lead to a high number of people that have particular injuries for limbs. In addition to persistent or temporary disabilities related to accidental injuries we must take into account that part of the population suffers from motor deficits of the hands due to stroke or diseases of various clinical nature. The most recurrent technological solutions to measure the rehabilitation or skill motor performance of the hand are glove-based devices, able to faithfully capture the movements of the hand and fingers. This paper presents a system for hand motion analysis based on 9-axis complete inertial modules and dedicated microcontroller which are fixed on fingers and forearm. The technological solution presented is able to track the patients' hand motions in real-time and then to send data through wireless communication reducing the clutter and the disadvantages of a glove equipped with sensors through a different technological structure. The device proposed has been tested in the study of Parkinson's disease.

  19. Preliminary Performance Assessment for the Waste Management Area C at the Hanford Site in Southeast Washington

    SciTech Connect

    Bergeron, Marcel P.; Singleton, Kristin M.; Eberlein, Susan J.

    2015-01-07

    A performance assessment (PA) of Single-Shell Tank (SST) Waste Management Area C (WMA C) located at the U.S. Department of Energy's (DOE) Hanford Site in southeastern Washington is being conducted to satisfy the requirements of the Hanford Federal Facility Agreement and Consent Order (HFFACO), as well as other Federal requirements and State-approved closure plans and permits. The WMP C PA assesses the fate, transport, and impacts of radionuclides and hazardous chemicals within residual wastes left in tanks and ancillary equipment and facilities in their assumed closed configuration and the subsequent risks to humans into the far future. The part of the PA focused on radiological impacts is being developed to meet the requirements for a closure authorization under DOE Order 435.1 that includes a waste incidental to reprocessing determination for residual wastes remaining in tanks, ancillary equipment, and facilities. An additional part of the PA will evaluate human health and environmental impacts from hazardous chemical inventories in residual wastes remaining in WMA C tanks, ancillary equipment, and facilities needed to meet the requirements for permitted closure under RCRA.

  20. Preliminary Investigation for Engine Performance by Using Tire-Derived Pyrolysis Oil-Diesel Blended Fuels

    NASA Astrophysics Data System (ADS)

    Rofiqul, Islam M.; Haniu, Hiroyuki; Alam, Beg R.; Takai, Kazunori

    In the first phase of the present study, the pyrolysis oil derived from light automotive tire waste has been characterized including fuel properties, elemental analyses, FT-IR, 1H-NMR, GC-MS and distillation. The studies on the oil show that it can be used as liquid fuel with a gross calorific value (GCV) of 42.00 MJ/kg and empirical formula of CH1.27O0.025N0.006. In the second phase of the investigation, the performance of a diesel engine was studied blending the pyrolysis oil with diesel fuel in different ratios. The experimental results show that the bsfc of pyrolysis oil-diesel blended fuels slightly increases and hence the brake thermal efficiency decreases compared to those of neat diesel. The pyrolysis oil-diesel blends show lower carbon monoxide (CO) emission but higher oxides of nitrogen (NOx) emissions than those of neat diesel. However, NOx emissions with pyrolysis oil-diesel blended fuels reduced when EGR was applied.