Set size influences the relationship between ANS acuity and math performance: a result of different strategies?

PubMed

Dietrich, Julia Felicitas; Nuerk, Hans-Christoph; Klein, Elise; Moeller, Korbinian; Huber, Stefan

2017-08-29

Previous research has proposed that the approximate number system (ANS) constitutes a building block for later mathematical abilities. Therefore, numerous studies investigated the relationship between ANS acuity and mathematical performance, but results are inconsistent. Properties of the experimental design have been discussed as a potential explanation of these inconsistencies. In the present study, we investigated the influence of set size and presentation duration on the association between non-symbolic magnitude comparison and math performance. Moreover, we focused on strategies reported as an explanation for these inconsistencies. In particular, we employed a non-symbolic magnitude comparison task and asked participants how they solved the task. We observed that set size was a significant moderator of the relationship between non-symbolic magnitude comparison and math performance, whereas presentation duration of the stimuli did not moderate this relationship. This supports the notion that specific design characteristics contribute to the inconsistent results. Moreover, participants reported different strategies including numerosity-based, visual, counting, calculation-based, and subitizing strategies. Frequencies of these strategies differed between different set sizes and presentation durations. However, we found no specific strategy, which alone predicted arithmetic performance, but when considering the frequency of all reported strategies, arithmetic performance could be predicted. Visual strategies made the largest contribution to this prediction. To conclude, the present findings suggest that different design characteristics contribute to the inconsistent findings regarding the relationship between non-symbolic magnitude comparison and mathematical performance by inducing different strategies and additional processes.

The plasmatron: Advanced mode thermionic energy conversion

NASA Technical Reports Server (NTRS)

Hansen, L. K.; Hatch, G. L.; Rasor, N. S.

1976-01-01

A theory of the plasmatron was developed. Also, a wide range of measurements were obtained with two versatile, research devices. To gain insight into plasmatron performance, the experimental results are compared with calculations based on the theoretical model of plasmatron operation. Results are presented which show that the plasma arc drop of the conventional arc (ignited) mode converter can be suppressed by use of an auxiliary ion source. The improved performance, however, is presently limited to low current densities because of voltage losses due to plasma resistance. This resistance loss could be suppressed by an increase in the plasma electron temperature or a decrease in spacing. Plasmatron performance characteristics for both argon and cesium are reported. The argon plasmatron has superior performance. Results are also presented for magnetic cutoff effects and for current distributing effects. These are shown to be important factors for the design of practical devices.

Performance Improvement Through Indexing of Turbine Airfoils. Part 2; Numerical Simulation

NASA Technical Reports Server (NTRS)

Griffin, Lisa W.; Huber, Frank W.; Sharma, Om P.

1996-01-01

An experimental/analytical study has been conducted to determine the performance improvements achievable by circumferentially indexing succeeding rows of turbine stator airfoils. A series of tests was conducted to experimentally investigate stator wake clocking effects on the performance of the space shuttle main engine (SSME) alternate turbopump development (ATD) fuel turbine test article (TTA). The results from this study indicate that significant increases in stage efficiency can be attained through application of this airfoil clocking concept. Details of the experiment and its results are documented in part 1 of this paper. In order to gain insight into the mechanisms of the performance improvement, extensive computational fluid dynamics (CFD) simulations were executed. The subject of the present paper is the initial results from the CFD investigation of the configurations and conditions detailed in part 1 of the paper. To characterize the aerodynamic environments in the experimental test series, two-dimensional (2D), time accurate, multistage, viscous analyses were performed at the TTA midspan. Computational analyses for five different circumferential positions of the first stage stator have been completed. Details of the computational procedure and the results are presented. The analytical results verify the experimentally demonstrated performance improvement and are compared with data whenever possible. Predictions of time-averaged turbine efficiencies as well as gas conditions throughout the flow field are presented. An initial understanding of the turbine performance improvement mechanism based on the results from this investigation is described.

Aerosol Data Assimilation at GMAO

NASA Technical Reports Server (NTRS)

da Silva, Arlindo M.; Buchard, Virginie

2017-01-01

This presentation presents an overview of the aerosol data assimilation work performed at GMAO. The GMAO Forward Processing system and the biomass burning emissions from QFED are first presented. Then, the current assimilation of Aerosol Optical Depth (AOD), performed by means of the analysis splitting method is briefly described, followed by some results on the quality control of observations using a Neural Network trained using AERONET AOD. Some applications are shown such as the Mount Pinatubo eruption in 1991 using the MERRA-2 aerosol dataset. Finally preliminary results on the EnKF implementation for aerosol assimilation are presented.

The Impact of Webinar-Webcast System on Learning Performance

ERIC Educational Resources Information Center

Nagy, Judit T.; Bernschütz, Mária

2016-01-01

Using online video presentations is increasingly gaining ground in higher education. Our present paper discusses the initial results of a longer research project and investigates the effect that the availability of online videos introduced to complement live presentations has on learning performance. The quasi-experimental research covered each…

Implementation of the qualities of radiodiagnostic: mammography

NASA Astrophysics Data System (ADS)

Pacífico, L. C.; Magalhães, L. A. G.; Peixoto, J. G. P.; Fernandes, E.

2018-03-01

The objective of the present study was to evaluate the expanded uncertainty of the mammographic calibration process and present the result of the internal audit performed at the Laboratory of Radiological Sciences (LCR). The qualities of the mammographic beans that are references in the LCR, comprises two irradiation conditions: no-attenuated beam and attenuated beam. Both had satisfactory results, with an expanded uncertainty equals 2,1%. The internal audit was performed, and the degree of accordance with the ISO/IEC 17025 was evaluated. The result of the internal audit was satisfactory. We conclude that LCR can perform calibrations on mammography qualities for end users.

VIDEO BLOGGING AND ENGLISH PRESENTATION PERFORMANCE: A PILOT STUDY.

PubMed

Alan Hung, Shao-Ting; Danny Huang, Heng-Tsung

2015-10-01

This study investigated the utility of video blogs in improving EFL students' performance in giving oral presentations and, further, examined the students' perceptions toward video blogging. Thirty-six English-major juniors participated in a semester-long video blog project for which they uploaded their 3-min. virtual presentation clips over 18 weeks. Their virtual presentation clips were rated by three raters using a scale for speaking performance that contained 14 presentation skills. Data sources included presentation clips, reflections, and interviews. The results indicated that the students' overall presentation performance improved significantly. In particular, among the 14 presentation skills projection, intonation, posture, introduction, conclusion, and purpose saw the most substantial improvement. Finally, the qualitative data revealed that learners perceived that the video blog project facilitated learning but increased anxiety.

Study of helicopterroll control effectiveness criteria

NASA Technical Reports Server (NTRS)

Heffley, Robert K.; Bourne, Simon M.; Curtiss, Howard C., Jr.; Hindson, William S.; Hess, Ronald A.

1986-01-01

A study of helicopter roll control effectiveness based on closed-loop task performance measurement and modeling is presented. Roll control critieria are based on task margin, the excess of vehicle task performance capability over the pilot's task performance demand. Appropriate helicopter roll axis dynamic models are defined for use with analytic models for task performance. Both near-earth and up-and-away large-amplitude maneuvering phases are considered. The results of in-flight and moving-base simulation measurements are presented to support the roll control effectiveness criteria offered. This Volume contains the theoretical analysis, simulation results and criteria development.

Statistical Analysis of NAS Parallel Benchmarks and LINPACK Results

NASA Technical Reports Server (NTRS)

Meuer, Hans-Werner; Simon, Horst D.; Strohmeier, Erich; Lasinski, T. A. (Technical Monitor)

1994-01-01

In the last three years extensive performance data have been reported for parallel machines both based on the NAS Parallel Benchmarks, and on LINPACK. In this study we have used the reported benchmark results and performed a number of statistical experiments using factor, cluster, and regression analyses. In addition to the performance results of LINPACK and the eight NAS parallel benchmarks, we have also included peak performance of the machine, and the LINPACK n and n(sub 1/2) values. Some of the results and observations can be summarized as follows: 1) All benchmarks are strongly correlated with peak performance. 2) LINPACK and EP have each a unique signature. 3) The remaining NPB can grouped into three groups as follows: (CG and IS), (LU and SP), and (MG, FT, and BT). Hence three (or four with EP) benchmarks are sufficient to characterize the overall NPB performance. Our poster presentation will follow a standard poster format, and will present the data of our statistical analysis in detail.

Detached Eddy Simulation of Flap Side-Edge Flow

NASA Technical Reports Server (NTRS)

Balakrishnan, Shankar K.; Shariff, Karim R.

2016-01-01

Detached Eddy Simulation (DES) of flap side-edge flow was performed with a wing and half-span flap configuration used in previous experimental and numerical studies. The focus of the study is the unsteady flow features responsible for the production of far-field noise. The simulation was performed at a Reynolds number (based on the main wing chord) of 3.7 million. Reynolds Averaged Navier-Stokes (RANS) simulations were performed as a precursor to the DES. The results of these precursor simulations match previous experimental and RANS results closely. Although the present DES simulations have not reached statistical stationary yet, some unsteady features of the developing flap side-edge flowfield are presented. In the final paper it is expected that statistically stationary results will be presented including comparisons of surface pressure spectra with experimental data.

Computation of Transverse Injection Into Supersonic Crossflow With Various Injector Orifice Geometries

NASA Technical Reports Server (NTRS)

Foster, Lancert; Engblom, William A.

2003-01-01

Computational results are presented for the performance and flow behavior of various injector geometries employed in transverse injection into a non-reacting Mach 1.2 flow. 3-D Reynolds-Averaged Navier Stokes (RANS) results are obtained for the various injector geometries using the Wind code with the Mentor s Shear Stress Transport turbulence model in both single and multi-species modes. Computed results for the injector mixing, penetration, and induced wall forces are presented. In the case of rectangular injectors, those longer in the direction of the freestream flow are predicted to generate the most mixing and penetration of the injector flow into the primary stream. These injectors are also predicted to provide the largest discharge coefficients and induced wall forces. Minor performance differences are indicated among diamond, circle, and square orifices. Grid sensitivity study results are presented which indicate consistent qualitative trends in the injector performance comparisons with increasing grid fineness.

Prediction of pump cavitation performance

NASA Technical Reports Server (NTRS)

Moore, R. D.

1974-01-01

A method for predicting pump cavitation performance with various liquids, liquid temperatures, and rotative speeds is presented. Use of the method requires that two sets of test data be available for the pump of interest. Good agreement between predicted and experimental results of cavitation performance was obtained for several pumps operated in liquids which exhibit a wide range of properties. Two cavitation parameters which qualitatively evaluate pump cavitation performance are also presented.

Semantic congruency but not temporal synchrony enhances long-term memory performance for audio-visual scenes.

PubMed

Meyerhoff, Hauke S; Huff, Markus

2016-04-01

Human long-term memory for visual objects and scenes is tremendous. Here, we test how auditory information contributes to long-term memory performance for realistic scenes. In a total of six experiments, we manipulated the presentation modality (auditory, visual, audio-visual) as well as semantic congruency and temporal synchrony between auditory and visual information of brief filmic clips. Our results show that audio-visual clips generally elicit more accurate memory performance than unimodal clips. This advantage even increases with congruent visual and auditory information. However, violations of audio-visual synchrony hardly have any influence on memory performance. Memory performance remained intact even with a sequential presentation of auditory and visual information, but finally declined when the matching tracks of one scene were presented separately with intervening tracks during learning. With respect to memory performance, our results therefore show that audio-visual integration is sensitive to semantic congruency but remarkably robust against asymmetries between different modalities.

Relative navigation requirements for automatic rendezvous and capture systems

NASA Technical Reports Server (NTRS)

Kachmar, Peter M.; Polutchko, Robert J.; Chu, William; Montez, Moises

1991-01-01

This paper will discuss in detail the relative navigation system requirements and sensor trade-offs for Automatic Rendezvous and Capture. Rendezvous navigation filter development will be discussed in the context of navigation performance requirements for a 'Phase One' AR&C system capability. Navigation system architectures and the resulting relative navigation performance for both cooperative and uncooperative target vehicles will be assessed. Relative navigation performance using rendezvous radar, star tracker, radiometric, laser and GPS navigation sensors during appropriate phases of the trajectory will be presented. The effect of relative navigation performance on the Integrated AR&C system performance will be addressed. Linear covariance and deterministic simulation results will be used. Evaluation of relative navigation and IGN&C system performance for several representative relative approach profiles will be presented in order to demonstrate the full range of system capabilities. A summary of the sensor requirements and recommendations for AR&C system capabilities for several programs requiring AR&C will be presented.

Preliminary performances measured on a CMOS long linear array for space application

NASA Astrophysics Data System (ADS)

Renard, Christophe; Artinian, Armand; Dantes, Didier; Lepage, Gérald; Diels, Wim

2017-11-01

This paper presents the design and the preliminary performances of a CMOS linear array, resulting from collaboration between Alcatel Alenia Space and Cypress Semiconductor BVBA, which takes advantage of emerging potentialities of CMOS technologies. The design of the sensor is presented: it includes 8000 panchromatic pixels with up to 25 rows used in TDI mode, and 4 lines of 2000 pixels for multispectral imaging. Main system requirements and detector tradeoffs are recalled, and the preliminary test results obtained with a first generation prototype are summarized and compared with predicted performances.

Performance Characteristics of Lithium-Ion Prototype Batteries for Mars Surveyor Program 2001 Lander

NASA Technical Reports Server (NTRS)

Smart, M. C.; Ratnakumar, B. V.; Whitcanack, L.; Surampudi, S.; Byers, J.; Marsh, R. A.

2000-01-01

A viewgraph presentation outlines the scientific payload, expected launch date and tasks, and an image of the Mars Surveyor 2001 Lander components. The Lander's battery specifications are given. The program objectives for the Li-ion cells for the Lander are listed, and results performance evaluation and cycle life performance tests are outlined for different temperatures. Cell charge characteristics are described, and test data is presented for charge capacity at varying temperatures. Capacity retention and storage characteristics tests are described and results are shown.

Hypersonic research engine/aerothermodynamic integration model, experimental results. Volume 2: Mach 6 performance

NASA Technical Reports Server (NTRS)

Andrews, E. H., Jr.; Mackley, E. A.

1976-01-01

Computer program performance results of a Mach 6 hypersonic research engine during supersonic and subsonic combustion modes were presented. The combustion mode transition was successfully performed, exit surveys made, and effects of altitude, angle of attack, and inlet spike position were determined during these tests.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sprik, Samuel; Kurtz, Jennifer M; Ainscough, Christopher D

In this presentation, the National Renewable Energy Laboratory presented aggregated analysis results on the performance of existing hydrogen stations, including performance, operation, utilization, maintenance, safety, hydrogen quality, and cost. The U.S. Department of Energy funds technology validation work at NREL through its National Fuel Cell Technology Evaluation Center (NFCTEC).

Inlet Reynolds number and temperature effects on the steady-state performance of a TFE731-2 turbofan engine

NASA Technical Reports Server (NTRS)

Bobula, G. A.; Lottig, R. A.

1977-01-01

Effects of varying engine inlet Reynolds number index (0.75, 0.50, 0.25, and 0.12) and temperature (289 and 244 K) on a TFE731-2 turbofan engine were evaluated. Results were classified as either compression system effects or effects on overall performance. Standard performance maps are used to present compression system performance. Overall performance parameters are presented as a function of low rotor speed corrected to engine inlet temperature.

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

NASA Technical Reports Server (NTRS)

Simon, Donald L.; Rinehart, Aidan W.

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.

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.

Unstructured Grid Euler Method Assessment for Longitudinal and Lateral/Directional Aerodynamic Performance Analysis of the HSR Technology Concept Airplane at Supersonic Cruise Speed

NASA Technical Reports Server (NTRS)

Ghaffari, Farhad

1999-01-01

Unstructured grid Euler computations, performed at supersonic cruise speed, are presented for a High Speed Civil Transport (HSCT) configuration, designated as the Technology Concept Airplane (TCA) within the High Speed Research (HSR) Program. The numerical results are obtained for the complete TCA cruise configuration which includes the wing, fuselage, empennage, diverters, and flow through nacelles at M (sub infinity) = 2.4 for a range of angles-of-attack and sideslip. Although all the present computations are performed for the complete TCA configuration, appropriate assumptions derived from the fundamental supersonic aerodynamic principles have been made to extract aerodynamic predictions to complement the experimental data obtained from a 1.675%-scaled truncated (aft fuselage/empennage components removed) TCA model. The validity of the computational results, derived from the latter assumptions, are thoroughly addressed and discussed in detail. The computed surface and off-surface flow characteristics are analyzed and the pressure coefficient contours on the wing lower surface are shown to correlate reasonably well with the available pressure sensitive paint results, particularly, for the complex flow structures around the nacelles. The predicted longitudinal and lateral/directional performance characteristics for the truncated TCA configuration are shown to correlate very well with the corresponding wind-tunnel data across the examined range of angles-of-attack and sideslip. The complementary computational results for the longitudinal and lateral/directional performance characteristics for the complete TCA configuration are also presented along with the aerodynamic effects due to empennage components. Results are also presented to assess the computational method performance, solution sensitivity to grid refinement, and solution convergence characteristics.

Talker and lexical effects on audiovisual word recognition by adults with cochlear implants.

PubMed

Kaiser, Adam R; Kirk, Karen Iler; Lachs, Lorin; Pisoni, David B

2003-04-01

The present study examined how postlingually deafened adults with cochlear implants combine visual information from lipreading with auditory cues in an open-set word recognition task. Adults with normal hearing served as a comparison group. Word recognition performance was assessed using lexically controlled word lists presented under auditory-only, visual-only, and combined audiovisual presentation formats. Effects of talker variability were studied by manipulating the number of talkers producing the stimulus tokens. Lexical competition was investigated using sets of lexically easy and lexically hard test words. To assess the degree of audiovisual integration, a measure of visual enhancement, R(a), was used to assess the gain in performance provided in the audiovisual presentation format relative to the maximum possible performance obtainable in the auditory-only format. Results showed that word recognition performance was highest for audiovisual presentation followed by auditory-only and then visual-only stimulus presentation. Performance was better for single-talker lists than for multiple-talker lists, particularly under the audiovisual presentation format. Word recognition performance was better for the lexically easy than for the lexically hard words regardless of presentation format. Visual enhancement scores were higher for single-talker conditions compared to multiple-talker conditions and tended to be somewhat better for lexically easy words than for lexically hard words. The pattern of results suggests that information from the auditory and visual modalities is used to access common, multimodal lexical representations in memory. The findings are discussed in terms of the complementary nature of auditory and visual sources of information that specify the same underlying gestures and articulatory events in speech.

Talker and Lexical Effects on Audiovisual Word Recognition by Adults With Cochlear Implants

PubMed Central

Kaiser, Adam R.; Kirk, Karen Iler; Lachs, Lorin; Pisoni, David B.

2012-01-01

The present study examined how postlingually deafened adults with cochlear implants combine visual information from lipreading with auditory cues in an open-set word recognition task. Adults with normal hearing served as a comparison group. Word recognition performance was assessed using lexically controlled word lists presented under auditory-only, visual-only, and combined audiovisual presentation formats. Effects of talker variability were studied by manipulating the number of talkers producing the stimulus tokens. Lexical competition was investigated using sets of lexically easy and lexically hard test words. To assess the degree of audiovisual integration, a measure of visual enhancement, Ra, was used to assess the gain in performance provided in the audiovisual presentation format relative to the maximum possible performance obtainable in the auditory-only format. Results showed that word recognition performance was highest for audiovisual presentation followed by auditory-only and then visual-only stimulus presentation. Performance was better for single-talker lists than for multiple-talker lists, particularly under the audiovisual presentation format. Word recognition performance was better for the lexically easy than for the lexically hard words regardless of presentation format. Visual enhancement scores were higher for single-talker conditions compared to multiple-talker conditions and tended to be somewhat better for lexically easy words than for lexically hard words. The pattern of results suggests that information from the auditory and visual modalities is used to access common, multimodal lexical representations in memory. The findings are discussed in terms of the complementary nature of auditory and visual sources of information that specify the same underlying gestures and articulatory events in speech. PMID:14700380

Review of Methods for Buildings Energy Performance Modelling

NASA Astrophysics Data System (ADS)

Krstić, Hrvoje; Teni, Mihaela

2017-10-01

Research presented in this paper gives a brief review of methods used for buildings energy performance modelling. This paper gives also a comprehensive review of the advantages and disadvantages of available methods as well as the input parameters used for modelling buildings energy performance. European Directive EPBD obliges the implementation of energy certification procedure which gives an insight on buildings energy performance via exiting energy certificate databases. Some of the methods for buildings energy performance modelling mentioned in this paper are developed by employing data sets of buildings which have already undergone an energy certification procedure. Such database is used in this paper where the majority of buildings in the database have already gone under some form of partial retrofitting - replacement of windows or installation of thermal insulation but still have poor energy performance. The case study presented in this paper utilizes energy certificates database obtained from residential units in Croatia (over 400 buildings) in order to determine the dependence between buildings energy performance and variables from database by using statistical dependencies tests. Building energy performance in database is presented with building energy efficiency rate (from A+ to G) which is based on specific annual energy needs for heating for referential climatic data [kWh/(m2a)]. Independent variables in database are surfaces and volume of the conditioned part of the building, building shape factor, energy used for heating, CO2 emission, building age and year of reconstruction. Research results presented in this paper give an insight in possibilities of methods used for buildings energy performance modelling. Further on it gives an analysis of dependencies between buildings energy performance as a dependent variable and independent variables from the database. Presented results could be used for development of new building energy performance predictive model.

OrbView-3 Technical Performance Evaluation 2005: Modulation Transfer Function

NASA Technical Reports Server (NTRS)

Cole, Aaron

2007-01-01

The Technical performance evaluation of OrbView-3 using the Modulation Transfer Function (MTF) is presented. The contents include: 1) MTF Results and Methodology; 2) Radiometric Calibration Methodology; and 3) Relative Radiometric Assessment Results

Correlation Between Geometric Similarity of Ice Shapes and the Resulting Aerodynamic Performance Degradation: A Preliminary Investigation Using WIND

NASA Technical Reports Server (NTRS)

Wright, William B.; Chung, James

1999-01-01

Aerodynamic performance calculations were performed using WIND on ten experimental ice shapes and the corresponding ten ice shapes predicted by LEWICE 2.0. The resulting data for lift coefficient and drag coefficient are presented. The difference in aerodynamic results between the experimental ice shapes and the LEWICE ice shapes were compared to the quantitative difference in ice shape geometry presented in an earlier report. Correlations were generated to determine the geometric features which have the most effect on performance degradation. Results show that maximum lift and stall angle can be correlated to the upper horn angle and the leading edge minimum thickness. Drag coefficient can be correlated to the upper horn angle and the frequency-weighted average of the Fourier coefficients. Pitching moment correlated with the upper horn angle and to a much lesser extent to the upper and lower horn thicknesses.

Comparison of indoor-outdoor thermal performance for the Sunpak evacuated tube liquid collector

NASA Technical Reports Server (NTRS)

1980-01-01

Performance data for current Sunpak production collectors is presented. The effects of an improved manifold are seen from the test results. The test results show excellent correlation between the solar simulator derived test results and outdoor test results. Also, because of different incident angle modifiers, the all-day efficiency of this collector with a diffuse reflector is comparable to the performance with the standard shaped specular reflector.

GOES Type III Loop Heat Pipe Life Test Results

NASA Technical Reports Server (NTRS)

Ottenstein, Laura

2011-01-01

The GOES Type III Loop Heat Pipe (LHP) was built as a life test unit for the loop heat pipes on the GOES N-Q series satellites. This propylene LHP was built by Dynatherm Corporation in 2000 and tested continuously for approximately 14 months. It was then put into storage for 3 years. Following the storage period, the LHP was tested at Swales Aerospace to verify that the loop performance hadn t changed. Most test results were consistent with earlier results. At the conclusion of testing at Swales, the LHP was transferred to NASA/GSFC for continued periodic testing. The LHP has been set up for testing in the Thermal Lab at GSFC since 2006. A group of tests consisting of start-ups, power cycles, and a heat transport limit test have been performed every six to nine months since March 2006. Tests results have shown no change in the loop performance over the five years of testing. This presentation will discuss the test hardware, test set-up, and tests performed. Test results to be presented include sample plots from individual tests, along with conductance measurements for all tests performed.

An Overview of Preliminary Computational and Experimental Results for the Semi-Span Super-Sonic Transport (S4T) Wind-Tunnel Model

NASA Technical Reports Server (NTRS)

Silva, Walter A.; Perry, Boyd, III; Florance, James R.; Sanetrik, Mark D.; Wieseman, Carol D.; Stevens, William L.; Funk, Christie J.; Hur, Jiyoung; Christhilf, David M.; Coulson, David A.

2011-01-01

A summary of computational and experimental aeroelastic and aeroservoelastic (ASE) results for the Semi-Span Super-Sonic Transport (S4T) wind-tunnel model is presented. A broad range of analyses and multiple ASE wind-tunnel tests of the S4T have been performed in support of the ASE element in the Supersonics Program, part of NASA's Fundamental Aeronautics Program. The computational results to be presented include linear aeroelastic and ASE analyses, nonlinear aeroelastic analyses using an aeroelastic CFD code, and rapid aeroelastic analyses using CFD-based reduced-order models (ROMs). Experimental results from two closed-loop wind-tunnel tests performed at NASA Langley's Transonic Dynamics Tunnel (TDT) will be presented as well.

Performance deterioration of commercial high-bypass ratio turbofan engines

NASA Technical Reports Server (NTRS)

Mehalic, C. M.; Ziemianski, J. A.

1980-01-01

The results of engine performance deterioration investigations based on historical data, special engine tests, and specific tests to define the influence of flight loads and component clearances on performance are presented. The results of analyses of several damage mechanisms that contribute to performance deterioration such as blade tip rubs, airfoil surface roughness and erosion, and thermal distortion are also included. The significance of these damage mechanisms on component and overall engine performance is discussed.

Test of acoustic tone source and propulsion performance of C8A Buffalo suppressor nozzle

NASA Technical Reports Server (NTRS)

Marrs, C. C.; Harkonen, D. L.; Okeefe, J. V.

1974-01-01

Results are presented for a static acoustic and propulsion performance ground test conducted at the Boeing hot nozzle facility on the C8A Buffalo noise suppressor nozzle. Various methods to remove a nozzle-associated 2000-Hz tone are evaluated. Results of testing this rectangular-array lobed nozzle for propulsion performance and acoustic directivity are reported. Recommendations for future nozzle modifications and further testing are included. Appendix A contains the test plan. Appendix B presents the test log. Appendix C contains plots of the one-third octave sound pressure levels recorded during the test. Appendix D describes the acoustic data recording and reduction systems. The performance data is tabulated in Appendix E.

Performance perceptions and self-focused attention predict post-event processing after a real-life social performance situation.

PubMed

Helbig-Lang, Sylvia; Poels, Vanja; Lincoln, Tania M

2016-11-01

Cognitive approaches to social anxiety suggest that an excessive brooding about one's performance in a social situation (post-event processing; PEP) is involved in the maintenance of anxiety. To date, most studies investigating PEP were conducted in laboratory settings. The present study sought to replicate previous findings on predictors of PEP after a naturalistic social performance situation. Sixty-five students, who had to give an evaluated presentation for credits, completed measures of trait social anxiety. Immediately after their presentation, participants rated state anxiety and attentional focus during the presentation, and provided an overall evaluation of their performance. One week after the presentation, they rated PEP during the preceding week, and reappraised their performance. Regression analyses demonstrated that the performance ratings after and self-focused attention during the presentation were unique predictors of PEP over and above the effects of trait and state anxiety. There was no evidence that PEP was associated with a biased recall of individual performance evaluations. The results support cognitive theories that emphasize the importance of negative self-perceptions in the development of social anxiety and related processes, and underline self-focused attention and self-evaluative processes as important targets during treatment.

FY 2016 Annual Performance Report

EPA Pesticide Factsheets

Presents detailed performance results, as measured against the targets established in EPA’s FY 2016 Annual Plan and Budget. The Executive Overview section analyzes key performance outcomes and links to FY 2016 program evaluations.

FY 2017 Annual Performance Report (APR)

EPA Pesticide Factsheets

Presents detailed performance results, as measured against the targets established in EPA’s FY 2017 Annual Plan and Budget. The Executive Overview section analyzes key performance outcomes and links to FY 2017 program evaluations.

FY 2015 Annual Performance Report

EPA Pesticide Factsheets

Presents detailed performance results, as measured against the targets established in EPA’s FY 2015 Annual Plan and Budget. The Executive Overview section analyzes key performance outcomes and links to FY 2015 program evaluations.

The Quiescent-Chamber Type Compression-Ignition Engine

NASA Technical Reports Server (NTRS)

Foster, H H

1937-01-01

Report presents the results of performance tests of a single-cylinder 4-stroke-cycle compression-ignition engine having a vertical disk form of combustion chamber without air flow. The number, size, and direction of the orifices of the fuel-injection nozzles used were independently varied. A table and graphs are presented showing the performance of the engine with different nozzles; results of tests at different compression ratios, boost pressures, and coolant temperatures are also included.

Performance Comparison of HPF and MPI Based NAS Parallel Benchmarks

NASA Technical Reports Server (NTRS)

Saini, Subhash

1997-01-01

Compilers supporting High Performance Form (HPF) features first appeared in late 1994 and early 1995 from Applied Parallel Research (APR), Digital Equipment Corporation, and The Portland Group (PGI). IBM introduced an HPF compiler for the IBM RS/6000 SP2 in April of 1996. Over the past two years, these implementations have shown steady improvement in terms of both features and performance. The performance of various hardware/ programming model (HPF and MPI) combinations will be compared, based on latest NAS Parallel Benchmark results, thus providing a cross-machine and cross-model comparison. Specifically, HPF based NPB results will be compared with MPI based NPB results to provide perspective on performance currently obtainable using HPF versus MPI or versus hand-tuned implementations such as those supplied by the hardware vendors. In addition, we would also present NPB, (Version 1.0) performance results for the following systems: DEC Alpha Server 8400 5/440, Fujitsu CAPP Series (VX, VPP300, and VPP700), HP/Convex Exemplar SPP2000, IBM RS/6000 SP P2SC node (120 MHz), NEC SX-4/32, SGI/CRAY T3E, and SGI Origin2000. We would also present sustained performance per dollar for Class B LU, SP and BT benchmarks.

LOX/LH2 vane pump for auxiliary propulsion systems

NASA Technical Reports Server (NTRS)

Hemminger, J. A.; Ulbricht, T. E.

1985-01-01

Positive displacement pumps offer potential efficiency advantages over centrifugal pumps for future low thrust space missions. Low flow rate applications, such as space station auxiliary propulsion or dedicated low thrust orbiter transfer vehicles, are typical of missions where low flow and high head rise challenge centrifugal pumps. The positive displacement vane pump for pumping of LOX and LH2 is investigated. This effort has included: (1) a testing program in which pump performance was investigated for differing pump clearances and for differing pump materials while pumping LN2, LOX, and LH2; and (2) an analysis effort, in which a comprehensive pump performance analysis computer code was developed and exercised. An overview of the theoretical framework of the performance analysis computer code is presented, along with a summary of analysis results. Experimental results are presented for pump operating in liquid nitrogen. Included are data on the effects on pump performance of pump clearance, speed, and pressure rise. Pump suction performance is also presented.

Between-individual comparisons in performance evaluation: a perspective from prospect theory.

PubMed

Wong, Kin Fai Ellick; Kwong, Jessica Y Y

2005-03-01

This article examines how between-individual comparisons influence performance evaluations in rating tasks. The authors demonstrated a systematic change in the perceived difference across ratees as a result of changing the way performance information is expressed. Study 1 found that perceived performance difference between 2 individuals was greater when their objective performance levels were presented with small numbers (e.g., absence rates of 2% vs. 5%) than when they were presented with large numbers (e.g., attendance rates of 98% vs. 95%). Extending this finding to situations involving trade-offs between multiple performance attributes across ratees, Study 2 showed that the relative preference for 1 ratee over another actually reversed when the presentation format of the performance information changed. The authors draw upon prospect theory to offer a theoretical framework describing the between-individual comparison aspect of performance evaluation.

Neural correlates of anticipation and processing of performance feedback in social anxiety.

PubMed

Heitmann, Carina Y; Peterburs, Jutta; Mothes-Lasch, Martin; Hallfarth, Marlit C; Böhme, Stephanie; Miltner, Wolfgang H R; Straube, Thomas

2014-12-01

Fear of negative evaluation, such as negative social performance feedback, is the core symptom of social anxiety. The present study investigated the neural correlates of anticipation and perception of social performance feedback in social anxiety. High (HSA) and low (LSA) socially anxious individuals were asked to give a speech on a personally relevant topic and received standardized but appropriate expert performance feedback in a succeeding experimental session in which neural activity was measured during anticipation and presentation of negative and positive performance feedback concerning the speech performance, or a neutral feedback-unrelated control condition. HSA compared to LSA subjects reported greater anxiety during anticipation of negative feedback. Functional magnetic resonance imaging results showed deactivation of medial prefrontal brain areas during anticipation of negative feedback relative to the control and the positive condition, and medial prefrontal and insular hyperactivation during presentation of negative as well as positive feedback in HSA compared to LSA subjects. The results indicate distinct processes underlying feedback processing during anticipation and presentation of feedback in HSA as compared to LSA individuals. In line with the role of the medial prefrontal cortex in self-referential information processing and the insula in interoception, social anxiety seems to be associated with lower self-monitoring during feedback anticipation, and an increased self-focus and interoception during feedback presentation, regardless of feedback valence. © 2014 Wiley Periodicals, Inc.

Disfluent presentations lead to the creation of more false memories.

PubMed

Sanchez, Christopher A; Naylor, Jamie S

2018-01-01

The creation of false memories within the Deese-Roediger-McDermott (DRM) paradigm has been shown to be sensitive to many factors such as task instructions, participant mood, or even presentation modality. However, do other simple perceptual differences also impact performance on the DRM and the creation of false memories? This study explores the potential impact of changes in perceptual disfluency on DRM performance. To test for a potential influence of disfluency on false memory creation, participants viewed lists under either perceptually disfluent conditions or not. Results indicated that disfluency did significantly impact performance in the DRM paradigm; more disfluent presentations significantly increased the recall and recognition of unpresented information, although they did not impact recall or recognition of presented information. Thus, although disfluency did impact performance, disfluency did not produce a positive benefit related to overall task performance. This finding instead suggests that more disfluent presentations can increase the likelihood that false memories are created, and provide little positive performance benefit.

Disfluent presentations lead to the creation of more false memories

PubMed Central

Naylor, Jamie S.

2018-01-01

The creation of false memories within the Deese-Roediger-McDermott (DRM) paradigm has been shown to be sensitive to many factors such as task instructions, participant mood, or even presentation modality. However, do other simple perceptual differences also impact performance on the DRM and the creation of false memories? This study explores the potential impact of changes in perceptual disfluency on DRM performance. To test for a potential influence of disfluency on false memory creation, participants viewed lists under either perceptually disfluent conditions or not. Results indicated that disfluency did significantly impact performance in the DRM paradigm; more disfluent presentations significantly increased the recall and recognition of unpresented information, although they did not impact recall or recognition of presented information. Thus, although disfluency did impact performance, disfluency did not produce a positive benefit related to overall task performance. This finding instead suggests that more disfluent presentations can increase the likelihood that false memories are created, and provide little positive performance benefit. PMID:29370255

Case studies in configuration control for redundant robots

NASA Technical Reports Server (NTRS)

Seraji, H.; Lee, T.; Colbaugh, R.; Glass, K.

1989-01-01

A simple approach to configuration control of redundant robots is presented. The redundancy is utilized to control the robot configuration directly in task space, where the task will be performed. A number of task-related kinematic functions are defined and combined with the end-effector coordinates to form a set of configuration variables. An adaptive control scheme is then utilized to ensure that the configuration variables track the desired reference trajectories as closely as possible. Simulation results are presented to illustrate the control scheme. The scheme has also been implemented for direct online control of a PUMA industrial robot, and experimental results are presented. The simulation and experimental results validate the configuration control scheme for performing various realistic tasks.

Impact performance of two bamboo-based laminated composites

Treesearch

Huanrong Liu; Zehui Jiang; Zhengjun Sun; Yan Yan; Zhiyong Cai; Xiubiao Zhang

2017-01-01

The present work aims to determine the impact performance of two bamboo-based laminated composites [bamboo/poplar laminated composite (BPLC) and bamboo/ glass fiber laminated composite (BGFLC)] using lowvelocity impact tests by a drop tower. In addition, fracture characteristics were evaluated using computed tomography (CT). Results showed that BPLC presented better...

Tribo-performance evaluation of ecofriendly brake friction composite materials

NASA Astrophysics Data System (ADS)

Kumar, Naresh; Singh, Tej; Grewal, G. S.

2018-05-01

This paper presents the potential of natural fibre in brake friction materials. Natural fibre filled ecofriendly brake friction materials were developed without Kevlar fibre evaluated for tribo-performance on a chase friction testing machine following SAE J 661a standard. Experimental results indicated that natural fibre enhances the fade performance, but depresses the friction and wear performance, whereas Kevlar fibre improves the friction, wear and recovery performance but depresses the fade performance. Also the results revealed that with the increase in natural fibre content, the friction and fade performances enhanced.

Modeling, system identification, and control of ASTREX

NASA Technical Reports Server (NTRS)

Abhyankar, Nandu S.; Ramakrishnan, J.; Byun, K. W.; Das, A.; Cossey, Derek F.; Berg, J.

1993-01-01

The modeling, system identification and controller design aspects of the ASTREX precision space structure are presented in this work. Modeling of ASTREX is performed using NASTRAN, TREETOPS and I-DEAS. The models generated range from simple linear time-invariant models to nonlinear models used for large angle simulations. Identification in both the time and frequency domains are presented. The experimental set up and the results from the identification experiments are included. Finally, controller design for ASTREX is presented. Simulation results using this optimal controller demonstrate the controller performance. Finally the future directions and plans for the facility are addressed.

SEASAT economic assessment. Volume 2: The SEASAT system description and performance. [performance prediction and systems analysis for seasat satellites

NASA Technical Reports Server (NTRS)

1975-01-01

Results are presented of preliminary trade-off studies of operational SEASAT systems. The trade-off studies were used as the basis for the estimation of costs and net benefits of the operational SEASAT system. Also presented are the preliminary results of simulation studies that were designed to lead to a measure of the impact of SEASAT data through the use of numerical weather forecast models.

Non preemptive soft real time scheduler: High deadline meeting rate on overload

NASA Astrophysics Data System (ADS)

Khalib, Zahereel Ishwar Abdul; Ahmad, R. Badlishah; El-Shaikh, Mohamed

2015-05-01

While preemptive scheduling has gain more attention among researchers, current work in non preemptive scheduling had shown promising result in soft real time jobs scheduling. In this paper we present a non preemptive scheduling algorithm meant for soft real time applications, which is capable of producing better performance during overload while maintaining excellent performance during normal load. The approach taken by this algorithm has shown more promising results compared to other algorithms including its immediate predecessor. We will present the analysis made prior to inception of the algorithm as well as simulation results comparing our algorithm named gutEDF with EDF and gEDF. We are convinced that grouping jobs utilizing pure dynamic parameters would produce better performance.

Integrated vehicle-based safety systems field operational test final program report.

DOT National Transportation Integrated Search

2011-06-01

"This document presents results from the light-vehicle and heavy-truck field operational tests performed as part of the Integrated Vehicle-Based Safety Systems (IVBSS) program. The findings are the result of analyses performed by the University of Mi...

Integrated Vehicle-Based Safety Systems Field Operational Test : Final Program Report

DOT National Transportation Integrated Search

2011-06-01

This document presents results from the light-vehicle and heavy-truck field operational tests performed as part of the Integrated Vehicle-Based Safety Systems (IVBSS) program. The findings are the result of analyses performed by the University of Mic...

Nuclear fuels status

NASA Technical Reports Server (NTRS)

Kania, Michael

1991-01-01

A discussion on coated particle fuel performance from a modular High Temperature Gas Reactor (HTGR) is presented along with experimental results. The following topics are covered: (1) the coated particle fuel concept; (2) the functional requirements; (3) performance limiting mechanisms; (4) fuel performance; and (5) methods/techniques for characterizing performance.

Depressive self-presentation: beyond self-handicapping.

PubMed

Weary, G; Williams, J P

1990-05-01

An experiment was conducted to examine the notion that depressives' responses would reflect a protective self-presentation style (Hill, Weary, & Williams, 1986), the underlying goal of which would be the avoidance of future performance demands and potential losses in self-esteem. In this study, depressed and nondepressed Ss were asked to perform a relatively simple visual-motor task. Half of the depressed and half of the nondepressed Ss were told that if they were successful at the task, they would be asked to perform a 2nd, similar task. The remaining Ss were given no such expectation of future performance. We predicted and found that depressed compared with nondepressed Ss strategically failed at the task when presented with the possibility of future performance and further losses in esteem. Moreover, this strategic failure was associated with some costs; depressed-future performance expectancy Ss experienced more discomfort or negative affect as a result of their performance. The relationship between this depressive self-presentation and self-handicapping strategies is discussed.

Studying Emotional Expression in Music Performance.

ERIC Educational Resources Information Center

Gabrielsson, Alf

1999-01-01

Explores the importance of emotional expression in music performance. Performers played music to express different emotions and then listening tests were conducted in order to determine whether the intended expressions were perceived. Presents and discusses the results. (CMK)

STARS: The Space Transportation Architecture Risk System

NASA Technical Reports Server (NTRS)

Greenberg, Joel S.

1997-01-01

Because of the need to perform comparisons between transportation systems that are likely to have significantly different levels of risk, both because of differing degrees of freedom in achieving desired performance levels and their different states of development and utilization, an approach has been developed for performing early comparisons of transportation architectures explicitly taking into account quantitative measures of uncertainty and resulting risk. The approach considers the uncertainty associated with the achievement of technology goals, the effect that the achieved level of technology will have on transportation system performance and the relationship between transportation system performance/capability and the ability to accommodate variations in payload mass. The consequences of system performance are developed in terms of expected values and associated standard deviations of nonrecurring, recurring and the present value of transportation system life cycle cost. Typical results are presented to illustrate the application of the methodology.

TOPEX Radar Altimeter Engineering Assessment Report. Update: Launch to January 1, 1997

NASA Technical Reports Server (NTRS)

Hancock, D. W., III; Hayne, G. S.; Brooks, R. L.; Lee, J. E.; Lockwood, D. W.

1997-01-01

The initial TOPEX Mission Radar Altimeter Engineering Assessment Report, in February 1994, presented performance results for the NASA Radar Altimeter on the TOPEX/POSEIDON spacecraft, from its launch in August 1992 to February 1994. There have been supplemental Engineering Assessment Reports, issued in March 1995 and again in May 1996, which updated the performance results through the end of calendar years 1994 and 1995, respectively. This supplement updates the altimeter performance to the end of calendar year 1996, and describes significant events that occurred during 1996. As the performance data base has expanded, and as analysis tools and techniques continue to evolve, the longer-term trends of the altimeter data have become more apparent. The updated findings are presented here.

Influence of Personality and Motivation on Oral Presentation Performance.

PubMed

Liang, Hsin-Yi; Kelsen, Brent

2018-01-19

Personality and motivation have been identified as influential variables associated with foreign language learning; however, few studies have investigated their effect on oral presentations. This study addresses the importance of both personality and motivation in students' collaborative oral presentation performance. A Big Five personality trait questionnaire measuring Extraversion, Agreeableness, Conscientiousness, Neuroticism and Openness to Experience, together with the Collaborative Inquiry-based Project Questionnaire measuring Task, Project Work, Reinforcement, Social Learning and Social Pressure motivational constructs were employed to evaluate 257 university students. In general, the results showed that Extraversion, Project Work and Social Pressure were significant correlates of oral presentation scores. The first result suggests that extraverts possess superiority in situations where oral language production is central to communication. This was particularly true for lower-level students, inferring that extraverted personalities can compensate for a lower English language ability. The second indicates that the inquiry-based nature of the assignments was an intrinsic motivator especially valued by extraverts. The third implies that extrinsic motivation was a factor influencing student performance. These findings extend previous research by highlighting the contextual relationships between these affective variables and performance in collaborative oral presentation contexts.

The Relationship between Binaural Benefit and Difference in Unilateral Speech Recognition Performance for Bilateral Cochlear Implant Users

PubMed Central

Yoon, Yang-soo; Li, Yongxin; Kang, Hou-Yong; Fu, Qian-Jie

2011-01-01

Objective The full benefit of bilateral cochlear implants may depend on the unilateral performance with each device, the speech materials, processing ability of the user, and/or the listening environment. In this study, bilateral and unilateral speech performances were evaluated in terms of recognition of phonemes and sentences presented in quiet or in noise. Design Speech recognition was measured for unilateral left, unilateral right, and bilateral listening conditions; speech and noise were presented at 0° azimuth. The “binaural benefit” was defined as the difference between bilateral performance and unilateral performance with the better ear. Study Sample 9 adults with bilateral cochlear implants participated. Results On average, results showed a greater binaural benefit in noise than in quiet for all speech tests. More importantly, the binaural benefit was greater when unilateral performance was similar across ears. As the difference in unilateral performance between ears increased, the binaural advantage decreased; this functional relationship was observed across the different speech materials and noise levels even though there was substantial intra- and inter-subject variability. Conclusions The results indicate that subjects who show symmetry in speech recognition performance between implanted ears in general show a large binaural benefit. PMID:21696329

The influence of school furniture on students' performance and physical responses: results of a systematic review.

PubMed

Castellucci, H I; Arezes, P M; Molenbroek, J F M; de Bruin, R; Viviani, C

2017-01-01

The purpose of this study was to determine, using a systematic review, whether the design and/or dimensions of school furniture affect the students' physical responses and/or their performance. Of the review studies, 64% presented positive results, i.e. proven effects; 24% presented negative effects or no change/effect; and the remaining 12% showed an unclear effect. The compatibility between school furniture dimensions and students' anthropometric characteristics was identified as a key factor for improving some students' physical responses. Design characteristics such as high furniture, sit-stand furniture, and tilt tables and seats also present positive effects. Finally, we concluded that further research should be conducted exploring various aspects of those variables, particularly focusing on more objective measures complemented by controlled and prospective design. Practitioner Summary: A systematic review of the literature presents a clearly positive effect of school furniture dimensions on students' performance and physical responses. Similar results appeared when school furniture design was tested. However, studying the effects of design and dimensions together produced an unclear positive effect.

Rewarding Progress, Reducing Debt: Early Results from Ohio's Performance-Based Scholarship Demonstration for Low-Income Parents

ERIC Educational Resources Information Center

Cha, Paulette; Patel, Reshma

2010-01-01

This report presents early results from a rigorous evaluation of a performance-based scholarship program that was implemented at three community colleges in Ohio during the 2008-2009 academic year. The program in Ohio that is the subject of this report is part of MDRC's national Performance-Based Scholarship (PBS) Demonstration, which was launched…

Raman Laser Spectrometer Development for ExoMars

NASA Astrophysics Data System (ADS)

Pérez, C.; Colombo, M.; Díaz, C.; Santamaría, P.; Ingley, R.; Parrot, Y.; Maurice, S.; Popp, J.; Tarcea, N.; Edwards, H. G. M.

2013-09-01

The Raman Laser Spectrometer is one of the Pasteur Payload instruments, within the ESA's ExoMars mission. The aim of the work presented here is to provide a summary of the instrument design and performances. For that the instrument current characteristics and performances, and its technological ass assessment program main results are presented and discussed.

Stimulus modality and working memory performance in Greek children with reading disabilities: additional evidence for the pictorial superiority hypothesis.

PubMed

Constantinidou, Fofi; Evripidou, Christiana

2012-01-01

This study investigated the effects of stimulus presentation modality on working memory performance in children with reading disabilities (RD) and in typically developing children (TDC), all native speakers of Greek. It was hypothesized that the visual presentation of common objects would result in improved learning and recall performance as compared to the auditory presentation of stimuli. Twenty children, ages 10-12, diagnosed with RD were matched to 20 TDC age peers. The experimental tasks implemented a multitrial verbal learning paradigm incorporating three modalities: auditory, visual, and auditory plus visual. Significant group differences were noted on language, verbal and nonverbal memory, and measures of executive abilities. A mixed-model MANOVA indicated that children with RD had a slower learning curve and recalled fewer words than TDC across experimental modalities. Both groups of participants benefited from the visual presentation of objects; however, children with RD showed the greatest gains during this condition. In conclusion, working memory for common verbal items is impaired in children with RD; however, performance can be facilitated, and learning efficiency maximized, when information is presented visually. The results provide further evidence for the pictorial superiority hypothesis and the theory that pictorial presentation of verbal stimuli is adequate for dual coding.

Iterative Code-Aided ML Phase Estimation and Phase Ambiguity Resolution

NASA Astrophysics Data System (ADS)

Wymeersch, Henk; Moeneclaey, Marc

2005-12-01

As many coded systems operate at very low signal-to-noise ratios, synchronization becomes a very difficult task. In many cases, conventional algorithms will either require long training sequences or result in large BER degradations. By exploiting code properties, these problems can be avoided. In this contribution, we present several iterative maximum-likelihood (ML) algorithms for joint carrier phase estimation and ambiguity resolution. These algorithms operate on coded signals by accepting soft information from the MAP decoder. Issues of convergence and initialization are addressed in detail. Simulation results are presented for turbo codes, and are compared to performance results of conventional algorithms. Performance comparisons are carried out in terms of BER performance and mean square estimation error (MSEE). We show that the proposed algorithm reduces the MSEE and, more importantly, the BER degradation. Additionally, phase ambiguity resolution can be performed without resorting to a pilot sequence, thus improving the spectral efficiency.

Overview of a stirling engine test project

NASA Technical Reports Server (NTRS)

Slaby, J. G.

1980-01-01

Tests were conducted on three Stirling engines ranging in size from 1.33 to 53 horsepower (1 to 40 kW). The tests were directed toward developing alternative, backup component concepts to improve engine efficiency and performance or to reduce costs. Some of the activities included investigating attractive concepts and materials for cooler-regenerator units, installing a jet impingement device on a Stirling engine to determine its potential for improved engine performance, and presenting performance maps for initial characterization of Stirling engines. The experiment results of the tests are presented along with predictions of results of future tests to be conducted on the Stirling engines.

Simulator for concurrent processing data flow architectures

NASA Technical Reports Server (NTRS)

Malekpour, Mahyar R.; Stoughton, John W.; Mielke, Roland R.

1992-01-01

A software simulator capability of simulating execution of an algorithm graph on a given system under the Algorithm to Architecture Mapping Model (ATAMM) rules is presented. ATAMM is capable of modeling the execution of large-grained algorithms on distributed data flow architectures. Investigating the behavior and determining the performance of an ATAMM based system requires the aid of software tools. The ATAMM Simulator presented is capable of determining the performance of a system without having to build a hardware prototype. Case studies are performed on four algorithms to demonstrate the capabilities of the ATAMM Simulator. Simulated results are shown to be comparable to the experimental results of the Advanced Development Model System.

Cold-air performance of a tip turbine designed to drive a lift fan. 3: Effect of simulated fan leakage on turbine performance

NASA Technical Reports Server (NTRS)

Haas, J. E.; Kofskey, M. G.; Hotz, G. M.; Futral, S. M., Jr.

1978-01-01

Performance data were obtained experimentally for a 0.4 linear scale version of the LF460 lift fan turbine for a range of scroll inlet total to diffuser exit static pressure ratios at design equivalent speed with simulated fan leakage air. Tests were conducted for full and partial admission operation with three separate combinations of rotor inlet and rotor exit leakage air. Data were compared to the results obtained from previous investigations in which no leakage air was present. Results are presented in terms of mass flow, torque, and efficiency.

Application-Specific Graph Sampling for Frequent Subgraph Mining and Community Detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Purohit, Sumit; Choudhury, Sutanay; Holder, Lawrence B.

Graph mining is an important data analysis methodology, but struggles as the input graph size increases. The scalability and usability challenges posed by such large graphs make it imperative to sample the input graph and reduce its size. The critical challenge in sampling is to identify the appropriate algorithm to insure the resulting analysis does not suffer heavily from the data reduction. Predicting the expected performance degradation for a given graph and sampling algorithm is also useful. In this paper, we present different sampling approaches for graph mining applications such as Frequent Subgrpah Mining (FSM), and Community Detection (CD). Wemore » explore graph metrics such as PageRank, Triangles, and Diversity to sample a graph and conclude that for heterogeneous graphs Triangles and Diversity perform better than degree based metrics. We also present two new sampling variations for targeted graph mining applications. We present empirical results to show that knowledge of the target application, along with input graph properties can be used to select the best sampling algorithm. We also conclude that performance degradation is an abrupt, rather than gradual phenomena, as the sample size decreases. We present the empirical results to show that the performance degradation follows a logistic function.« less

Oscillating flow loss test results in Stirling engine heat exchangers

NASA Technical Reports Server (NTRS)

Koester, G.; Howell, S.; Wood, G.; Miller, E.; Gedeon, D.

1990-01-01

The results are presented for a test program designed to generate a database of oscillating flow loss information that is applicable to Stirling engine heat exchangers. The tests were performed on heater/cooler tubes of various lengths and entrance/exit configurations, on stacked and sintered screen regenerators of various wire diameters and on Brunswick and Metex random fiber regenerators. The test results were performed over a range of oscillating flow parameters consistent with Stirling engine heat exchanger experience. The tests were performed on the Sunpower oscillating flow loss rig which is based on a variable stroke and variable frequency linear drive motor. In general, the results are presented by comparing the measured oscillating flow losses to the calculated flow losses. The calculated losses are based on the cycle integration of steady flow friction factors and entrance/exit loss coefficients.

Comprehensive Analysis Modeling of Small-Scale UAS Rotors

NASA Technical Reports Server (NTRS)

Russell, Carl R.; Sekula, Martin K.

2017-01-01

Multicopter unmanned aircraft systems (UAS), or drones, have continued their explosive growth in recent years. With this growth comes demand for increased performance as the limits of existing technologies are reached. In order to better design multicopter UAS aircraft, better performance prediction tools are needed. This paper presents the results of a study aimed at using the rotorcraft comprehensive analysis code CAMRAD II to model a multicopter UAS rotor in hover. Parametric studies were performed to determine the level of fidelity needed in the analysis code inputs to achieve results that match test data. Overall, the results show that CAMRAD II is well suited to model small-scale UAS rotors in hover. This paper presents the results of the parametric studies as well as recommendations for the application of comprehensive analysis codes to multicopter UAS rotors.

Event related potentials to digit learning: tracking neurophysiologic changes accompanying recall performance.

PubMed

Jongsma, Marijtje L A; Gerrits, Niels J H M; van Rijn, Clementina M; Quiroga, Rodrigo Quian; Maes, Joseph H R

2012-07-01

The aim of this study was to track recall performance and event-related potentials (ERPs) across multiple trials in a digit-learning task. When a sequence is practiced by repetition, the number of errors typically decreases and a learning curve emerges. Until now, almost all ERP learning and memory research has focused on effects after a single presentation and, therefore, fails to capture the dynamic changes that characterize a learning process. However, the current study used a free-recall task in which a sequence of ten auditory digits was presented repeatedly. Auditory sequences of ten digits were presented in a logical order (control sequences) or in a random order (experimental sequences). Each sequence was presented six times. Participants had to reproduce the sequence after each presentation. EEG recordings were made at the time of the digit presentations. Recall performance for the control sequences was close to asymptote right after the first learning trial, whereas performance for the experimental sequences initially displayed primacy and recency effects. However, these latter effects gradually disappeared over the six repetitions, resulting in near-asymptotic recall performance for all digits. The performance improvement for the middle items of the list was accompanied by an increase in P300 amplitude, implying a close correspondence between this ERP component and the behavioral data. These results, which were discussed in the framework of theories on the functional significance of the P300 amplitude, add to the scarce empirical data on the dynamics of ERP responses in the process of intentional learning. Copyright © 2011 Elsevier B.V. All rights reserved.

Robot-operated quality control station based on the UTT method

NASA Astrophysics Data System (ADS)

Burghardt, Andrzej; Kurc, Krzysztof; Szybicki, Dariusz; Muszyńska, Magdalena; Nawrocki, Jacek

2017-03-01

This paper presents a robotic test stand for the ultrasonic transmission tomography (UTT) inspection of stator vane thickness. The article presents the method of the test stand design in Autodesk Robot Structural Analysis Professional 2013 software suite. The performance of the designed test stand solution was simulated in the RobotStudio software suite. The operating principle of the test stand measurement system is presented with a specific focus on the measurement strategy. The results of actual wall thickness measurements performed on stator vanes are presented.

Modeling of dielectric elastomer as electromechanical resonator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Bo, E-mail: liboxjtu@mail.xjtu.edu.cn; Liu, Lei; Chen, Hualing

Dielectric elastomers (DEs) feature nonlinear dynamics resulting from an electromechanical coupling. Under alternating voltage, the DE resonates with tunable performances. We present an analysis of the nonlinear dynamics of a DE as electromechanical resonator (DEER) configured as a pure shear actuator. A theoretical model is developed to characterize the complex performance under different boundary conditions. Physical mechanisms are presented and discussed. Chaotic behavior is also predicted, illustrating instabilities in the dynamics. The results provide a guide to the design and application of DEER in haptic devices.

Radioactive threat detection using scintillant-based detectors

NASA Astrophysics Data System (ADS)

Chalmers, Alex

2004-09-01

An update to the performance of AS&E's Radioactive Threat Detection sensor technology. A model is presented detailing the components of the scintillant-based RTD system employed in AS&E products aimed at detecting radiological WMD. An overview of recent improvements in the sensors, electrical subsystems and software algorithms are presented. The resulting improvements in performance are described and sample results shown from existing systems. Advanced and future capabilities are described with an assessment of their feasibility and their application to Homeland Defense.

STS-73 (USML-2) Final Report

NASA Technical Reports Server (NTRS)

Rice, James E.

1996-01-01

The report is organized into sections representing the phases of work performed in analyzing the STS-73 (USML-2) results. Section 1 briefly outlines the Orbital Acceleration Research Experiment (OARE), system features, coordinates, and measurement parameters. Section 2 describes the results from STS-73. The mission description, data calibration, and representative data obtained on STS-73 are presented. Also, the anomalous performance of OARE on STS-73 is discussed. Finally, Section 3 presents a discussion of accuracy achieved and achievable with OARE.

OARE STS-75 (USMP-3) Final Report

NASA Technical Reports Server (NTRS)

Rice, James E.

1996-01-01

The report is organized into sections representing the phases of work performed in analyzing the STS-75 (USMP-3) results. Section 1 briefly outlines the Orbital Acceleration Research Experiment (OARE) system features, coordinates, and measurement parameters. Section 2 describes the results from STS-75. The mission description, data calibration, and representative data obtained on STS-75 are presented. Also, the anomalous performance of OARE on STS-75 is discussed. Finally, Section 3 presents a discussion of accuracy achieved and achievable with OARE.

Hydrocarbon group type determination in jet fuels by high performance liquid chromatography

NASA Technical Reports Server (NTRS)

Antoine, A. C.

1977-01-01

Thirty-two jet and diesel fuel samples of varying chemical composition and physical properties were prepared from oil shale and coal syncrudes. Hydrocarbon types in these samples were determined by a fluorescent indicator adsorption analysis, and the results from three laboratories are presented and compared. Two methods of rapid high performance liquid chromatography were used to analyze some of the samples, and these results are also presented and compared. Two samples of petroleum-based Jet A fuel are similarly analyzed.

Portable Life Support Subsystem Thermal Hydraulic Performance Analysis

NASA Technical Reports Server (NTRS)

Barnes, Bruce; Pinckney, John; Conger, Bruce

2010-01-01

This paper presents the current state of the thermal hydraulic modeling efforts being conducted for the Constellation Space Suit Element (CSSE) Portable Life Support Subsystem (PLSS). The goal of these efforts is to provide realistic simulations of the PLSS under various modes of operation. The PLSS thermal hydraulic model simulates the thermal, pressure, flow characteristics, and human thermal comfort related to the PLSS performance. This paper presents modeling approaches and assumptions as well as component model descriptions. Results from the models are presented that show PLSS operations at steady-state and transient conditions. Finally, conclusions and recommendations are offered that summarize results, identify PLSS design weaknesses uncovered during review of the analysis results, and propose areas for improvement to increase model fidelity and accuracy.

Simultaneous and successive cognitive processes in the Mueller-Lyer illusion.

PubMed

Jarman, R F

1979-03-01

Performance in the Mueller-Lyer Illusion was analyzed for whole and partial presentations of the figure. S s were 120 third grade boys and girls. Four experimental groups were formed with the use of the human abilities model of simultaneous and successive syntheses, and the two types of presentation were given to each group. Results indicated that illusory effects in both presentations of the figure were significantly reduced by ability in simultaneous synthesis. Performance in the two presentations was also affected by successive ability, but these effects were in opposite directions for the two forms of presentation. The results did not support Piaget's theory of perceptual development, although they were consistent with the theory of simultaneous and successive syntheses. Suggestions are made for the design of future research.

Sequential lineup presentation promotes less-biased criterion setting but does not improve discriminability.

PubMed

Palmer, Matthew A; Brewer, Neil

2012-06-01

When compared with simultaneous lineup presentation, sequential presentation has been shown to reduce false identifications to a greater extent than it reduces correct identifications. However, there has been much debate about whether this difference in identification performance represents improved discriminability or more conservative responding. In this research, data from 22 experiments that compared sequential and simultaneous lineups were analyzed using a compound signal-detection model, which is specifically designed to describe decision-making performance on tasks such as eyewitness identification tests. Sequential (cf. simultaneous) presentation did not influence discriminability, but produced a conservative shift in response bias that resulted in less-biased choosing for sequential than simultaneous lineups. These results inform understanding of the effects of lineup presentation mode on eyewitness identification decisions.

Statistical assessment of speech system performance

NASA Technical Reports Server (NTRS)

Moshier, Stephen L.

1977-01-01

Methods for the normalization of performance tests results of speech recognition systems are presented. Technological accomplishments in speech recognition systems, as well as planned research activities are described.

Results on SUSY and Higgs searches at CMS

ScienceCinema

Tapper, Alex

2018-02-16

We present the results of searches for Supersymmetry and the Higgs boson performed using data collected in 2010 by the CMS experiment at the LHC in pp-collisions at a centre-of-mass energy of 7 TeV. Searches for Supersymmetry are performed in all-hadronic final states with jets and missing transverse energy and in final states including one or more isolated leptons or photons. No evidence for new physics is observed and limits are set on the predictions of a range of Supersymmetric scenarios. The results of searches for the Higgs boson are presented and limits set.

Causes of dissociation between subjective workload measures and performance - Caveats for the use of subjective assessments

NASA Technical Reports Server (NTRS)

Vidulich, M. A.; Wickens, C. D.

1985-01-01

Dissociations between subjective workload assessments and performance were investigated. The difficulty of a Sternberg memory search task was manipulated by varying stimulus presentation rate, stimulus discernibility, value of good performance, and automaticity of performance. All Sternberg task conditions were performed both alone and concurrently with a tracking task. Bipolar subjective workload assessments were collected. Dissociations between workload and performance were found related to automaticity, presentation rate, and motivation level. The results were interpreted as supporting the hypothesis that the specific cognitive processes responsible for subjective assessments can differ from those responsible for performance. The potential contamination these dissociations could inflict on operational workload assessments is discussed.

Performance of Backshort-Under-Grid Kilopixel TES Arrays for HAWC+

NASA Technical Reports Server (NTRS)

Staguhn, J. G.; Benford, D. J.; Dowell, C. D.; Fixsen, D. J.; Hilton, G. C.; Irwin, K. D.; Jhabvala, C. A.; Maher, S. F.; Miller, T. M.; Moseley, S. H.;

Optimization Model for Web Based Multimodal Interactive Simulations.

PubMed

Halic, Tansel; Ahn, Woojin; De, Suvranu

2015-07-15

This paper presents a technique for optimizing the performance of web based multimodal interactive simulations. For such applications where visual quality and the performance of simulations directly influence user experience, overloading of hardware resources may result in unsatisfactory reduction in the quality of the simulation and user satisfaction. However, optimization of simulation performance on individual hardware platforms is not practical. Hence, we present a mixed integer programming model to optimize the performance of graphical rendering and simulation performance while satisfying application specific constraints. Our approach includes three distinct phases: identification, optimization and update . In the identification phase, the computing and rendering capabilities of the client device are evaluated using an exploratory proxy code. This data is utilized in conjunction with user specified design requirements in the optimization phase to ensure best possible computational resource allocation. The optimum solution is used for rendering (e.g. texture size, canvas resolution) and simulation parameters (e.g. simulation domain) in the update phase. Test results are presented on multiple hardware platforms with diverse computing and graphics capabilities to demonstrate the effectiveness of our approach.

Benchmarking the ATLAS software through the Kit Validation engine

NASA Astrophysics Data System (ADS)

De Salvo, Alessandro; Brasolin, Franco

2010-04-01

The measurement of the experiment software performance is a very important metric in order to choose the most effective resources to be used and to discover the bottlenecks of the code implementation. In this work we present the benchmark techniques used to measure the ATLAS software performance through the ATLAS offline testing engine Kit Validation and the online portal Global Kit Validation. The performance measurements, the data collection, the online analysis and display of the results will be presented. The results of the measurement on different platforms and architectures will be shown, giving a full report on the CPU power and memory consumption of the Monte Carlo generation, simulation, digitization and reconstruction of the most CPU-intensive channels. The impact of the multi-core computing on the ATLAS software performance will also be presented, comparing the behavior of different architectures when increasing the number of concurrent processes. The benchmark techniques described in this paper have been used in the HEPiX group since the beginning of 2008 to help defining the performance metrics for the High Energy Physics applications, based on the real experiment software.

Optimization Model for Web Based Multimodal Interactive Simulations

PubMed Central

Halic, Tansel; Ahn, Woojin; De, Suvranu

2015-01-01

This paper presents a technique for optimizing the performance of web based multimodal interactive simulations. For such applications where visual quality and the performance of simulations directly influence user experience, overloading of hardware resources may result in unsatisfactory reduction in the quality of the simulation and user satisfaction. However, optimization of simulation performance on individual hardware platforms is not practical. Hence, we present a mixed integer programming model to optimize the performance of graphical rendering and simulation performance while satisfying application specific constraints. Our approach includes three distinct phases: identification, optimization and update. In the identification phase, the computing and rendering capabilities of the client device are evaluated using an exploratory proxy code. This data is utilized in conjunction with user specified design requirements in the optimization phase to ensure best possible computational resource allocation. The optimum solution is used for rendering (e.g. texture size, canvas resolution) and simulation parameters (e.g. simulation domain) in the update phase. Test results are presented on multiple hardware platforms with diverse computing and graphics capabilities to demonstrate the effectiveness of our approach. PMID:26085713

Preliminary test results for Li-SOCl2 high-rate D cells

NASA Technical Reports Server (NTRS)

Bragg, Bobby J.; Johnson, Paul

1992-01-01

The performance and abuse characteristics of 55 D-size lithium-thionyl chloride (Li-SOCl2) cells are evaluated at relatively high rates. Results from the following tests are presented: shock test, vibration test, capacity performance, uninsulated short circuit, high temperature exposure, and overdischarge.

Transit Performance Monitoring System (TPMS) results : summary report, phase 3

DOT National Transportation Integrated Search

2004-06-01

This report presents the results of the third phase of a project to implement a transit performance monitoring system (TPMS). The TPMS was designed to collect data on transit customers through the use of on-board surveys. The long-term goal of the TP...

Preliminary test results for Li-SOCl2 high-rate D cells

NASA Astrophysics Data System (ADS)

Bragg, Bobby J.; Johnson, Paul

1992-02-01

The performance and abuse characteristics of 55 D-size lithium-thionyl chloride (Li-SOCl2) cells are evaluated at relatively high rates. Results from the following tests are presented: shock test, vibration test, capacity performance, uninsulated short circuit, high temperature exposure, and overdischarge.

Transit Performance Monitoring System (TPMS) results : summary report, phases 1 and 2

DOT National Transportation Integrated Search

2002-02-01

This report presents the results of a project to implement a transit performance monitoring system (TPMS). The TPMS was designed to collect data on transit customers through the use of on-board surveys. The long-term goal of the TPMS initiative is to...

Uniform circular array for structural health monitoring of composite structures

NASA Astrophysics Data System (ADS)

Stepinski, Tadeusz; Engholm, Marcus

2008-03-01

Phased array with all-azimuth angle coverage would be extremely useful in structural health monitoring (SHM) of planar structures. One method to achieve the 360° coverage is to use uniform circular arrays (UCAs). In this paper we present the concept of UCA adapted for SHM applications. We start from a brief presentation of UCA beamformers based on the principle of phase mode excitation. UCA performance is illustrated by the results of beamformer simulations performed for the narrowband and wideband ultrasonic signals. Preliminary experimental results obtained with UCA used for the reception of ultrasonic signals propagating in an aluminum plate are also presented.

Integrated flight/propulsion control design for a STOVL aircraft using H-infinity control design techniques

NASA Technical Reports Server (NTRS)

Garg, Sanjay; Ouzts, Peter J.

1991-01-01

Results are presented from an application of H-infinity control design methodology to a centralized integrated flight propulsion control (IFPC) system design for a supersonic Short Takeoff and Vertical Landing (STOVL) fighter aircraft in transition flight. The emphasis is on formulating the H-infinity control design problem such that the resulting controller provides robustness to modeling uncertainties and model parameter variations with flight condition. Experience gained from a preliminary H-infinity based IFPC design study performed earlier is used as the basis to formulate the robust H-infinity control design problem and improve upon the previous design. Detailed evaluation results are presented for a reduced order controller obtained from the improved H-infinity control design showing that the control design meets the specified nominal performance objectives as well as provides stability robustness for variations in plant system dynamics with changes in aircraft trim speed within the transition flight envelope. A controller scheduling technique which accounts for changes in plant control effectiveness with variation in trim conditions is developed and off design model performance results are presented.

Investigation of the effects of pile jetting and performing

DOT National Transportation Integrated Search

1999-07-01

This report presents the results of an experimental study performed with similar model piles installed using (1) impact driving (2) jetting and (3) performing in a sandy soil (with 10% clay) compacted to different unit weights under saturated and uns...

Evaluation of the Cedar memory system: Configuration of 16 by 16

NASA Technical Reports Server (NTRS)

Gallivan, K.; Jalby, W.; Wijshoff, H.

1991-01-01

Some basic results on the performance of the Cedar multiprocessor system are presented. Empirical results on the 16 processor 16 memory bank system configuration, which show the behavior of the Cedar system under different modes of operation are presented.

Effects of ionospheric modification on system performance

NASA Astrophysics Data System (ADS)

Ganguly, Suman

1989-12-01

Controlled ionospheric modification can be used for disrupting as well as facilitating communication and radar systems. After briefly describing the results achieved with the present day ionospheric modification facilities, a scenario is presented for the generation of strong and significant ionospheric modification. A few schemes are presented for the development of modern high power facilities using the state of the art technology and then the impact of such facilities on the system performance is described.

An Integrated Architecture for Aircraft Engine Performance Monitoring and Fault Diagnostics: Engine Test Results

NASA Technical Reports Server (NTRS)

Rinehart, Aidan W.; Simon, Donald L.

2015-01-01

This paper presents a model-based architecture for performance trend monitoring and gas path fault diagnostics designed for analyzing streaming transient aircraft engine measurement data. The technique analyzes residuals between sensed engine outputs and model predicted outputs for fault detection and isolation purposes. Diagnostic results from the application of the approach to test data acquired from an aircraft turbofan engine are presented. The approach is found to avoid false alarms when presented nominal fault-free data. Additionally, the approach is found to successfully detect and isolate gas path seeded-faults under steady-state operating scenarios although some fault misclassifications are noted during engine transients. Recommendations for follow-on maturation and evaluation of the technique are also presented.

An Integrated Architecture for Aircraft Engine Performance Monitoring and Fault Diagnostics: Engine Test Results

NASA Technical Reports Server (NTRS)

Rinehart, Aidan W.; Simon, Donald L.

2014-01-01

This paper presents a model-based architecture for performance trend monitoring and gas path fault diagnostics designed for analyzing streaming transient aircraft engine measurement data. The technique analyzes residuals between sensed engine outputs and model predicted outputs for fault detection and isolation purposes. Diagnostic results from the application of the approach to test data acquired from an aircraft turbofan engine are presented. The approach is found to avoid false alarms when presented nominal fault-free data. Additionally, the approach is found to successfully detect and isolate gas path seeded-faults under steady-state operating scenarios although some fault misclassifications are noted during engine transients. Recommendations for follow-on maturation and evaluation of the technique are also presented.

Charge exchange contamination of CRIT-II barium CIV experiment. [critical ionization velocity in ionosphere

NASA Technical Reports Server (NTRS)

Swenson, G. R.; Mende, S. B.; Meyerott, R. E.; Rairden, R. L.

1991-01-01

Experiments have been recently performed which attempted to confirm critical ionization velocity (CIV) ionization by deploying chemicals at high velocity in the ionosphere. Specifically, the CRIT-II rocket performed a barium release in the ionosphere, where observations of Ba(+) resonant emissions following the release are believed to have resulted from the CIV process. Calculations are presented which suggest a significant fraction (if not all) of the Ba(+) observed likely resulted from charge exchange with the thermosphere ions and not through CIV processes. The results presented here are pertinent to other CIV experiments performed in the ionosphere. It is recommended that laboratory measurements should be made of the charge exchange cross section between O(+) and Ba as well as other metal vapors used in CIV experiments.

The digital phase-locked loop as a near-optimum FM demodulator.

NASA Technical Reports Server (NTRS)

Kelly, C. N.; Gupta, S. C.

1972-01-01

This paper presents an approach to the optimum digital demodulation of a continuous-time FM signal using stochastic estimation theory. The primary result is a digital phase-locked loop realization possessing performance characteristics that approach those of the analog counterpart. Some practical considerations are presented and simulation results for a first-order message model are presented.

Hypersonic research engine/aerothermodynamic integration model: Experimental results. Volume 3: Mach 7 component integration and performance

NASA Technical Reports Server (NTRS)

Andrews, E. H., Jr.; Mackley, E. A.

1976-01-01

The NASA Hypersonic Research Engine Project was undertaken to design, develop, and construct a hypersonic research ramjet engine for high performance and to flight test the developed concept on the X-15-2A airplane over the speed range from Mach 3 to 8. Computer program results are presented here for the Mach 7 component integration and performance tests.

From SED HI concept to Pleiades FM detection unit measurements

NASA Astrophysics Data System (ADS)

Renard, Christophe; Dantes, Didier; Neveu, Claude; Lamard, Jean-Luc; Oudinot, Matthieu; Materne, Alex

2017-11-01

The first flight model PLEIADES high resolution instrument under Thales Alenia Space development, on behalf of CNES, is currently in integration and test phases. Based on the SED HI detection unit concept, PLEIADES detection unit has been fully qualified before the integration at telescope level. The main radiometric performances have been measured on engineering and first flight models. This paper presents the results of performances obtained on the both models. After a recall of the SED HI concept, the design and performances of the main elements (charge coupled detectors, focal plane and video processing unit), detection unit radiometric performances are presented and compared to the instrument specifications for the panchromatic and multispectral bands. The performances treated are the following: - video signal characteristics, - dark signal level and dark signal non uniformity, - photo-response non uniformity, - non linearity and differential non linearity, - temporal and spatial noises regarding system definitions PLEIADES detection unit allows tuning of different functions: reference and sampling time positioning, anti-blooming level, gain value, TDI line number. These parameters are presented with their associated criteria of optimisation to achieve system radiometric performances and their sensitivities on radiometric performances. All the results of the measurements performed by Thales Alenia Space on the PLEIADES detection units demonstrate the high potential of the SED HI concept for Earth high resolution observation system allowing optimised performances at instrument and satellite levels.

Performance of MarSite Multi parameter Borehole Instrumentation

NASA Astrophysics Data System (ADS)

Guralp, Cansun; Tunc, Suleyman; Ozel, Oguz; Meral Ozel, Nurcan; Necmioglu, Ocal

2017-04-01

In this paper we present two year results obtained from the integrated multiparameter borehole system at Marsite. The very broad band (VBB) system have been operating since installation in November 2014; one year in a water filled borehole and one year in a dry Borehole. from January 2016. The real time data has been available to the community. The two Borehole environments are compared showing the superior performance of dry borehole environ- ment compared to water filled for a very broad band (VBB) seismometer. The practical considerations applied in both borehole installations are compared and the best borehole practical installation techniques are presented and discussed. The data is also compared with a surface 120 second broad band sensor and the seismic arrays with in MarSite region. The very long term performance, (one year data in a dry hole) of the VBB Borehole seismometer and the Dilatometer will be presented The high frequency performance of the VBB seismometer which extends to 150 Hz and the dilatometer are compared characterizing the results from the dilatometer.

Run-time parallelization and scheduling of loops

NASA Technical Reports Server (NTRS)

Saltz, Joel H.; Mirchandaney, Ravi; Crowley, Kay

1991-01-01

Run-time methods are studied to automatically parallelize and schedule iterations of a do loop in certain cases where compile-time information is inadequate. The methods presented involve execution time preprocessing of the loop. At compile-time, these methods set up the framework for performing a loop dependency analysis. At run-time, wavefronts of concurrently executable loop iterations are identified. Using this wavefront information, loop iterations are reordered for increased parallelism. Symbolic transformation rules are used to produce: inspector procedures that perform execution time preprocessing, and executors or transformed versions of source code loop structures. These transformed loop structures carry out the calculations planned in the inspector procedures. Performance results are presented from experiments conducted on the Encore Multimax. These results illustrate that run-time reordering of loop indexes can have a significant impact on performance.

NEXT Ion Engine 2000 Hour Wear Test Results

NASA Technical Reports Server (NTRS)

Soulas, George C.; Kamhawi, Hani; Patterson, Michael J.; Britton, Melissa A.; Frandina, Michael M.

2004-01-01

The results of the NEXT 2000 h wear test are presented. This test was conducted with a 40 cm engineering model ion engine, designated EM1, at a 3.52 A beam current and 1800 V beam power supply voltage. Performance tests, which were conducted over a throttling range of 1.1 to 6.9 kW throughout the wear test, demonstrated that EM1 satisfied all thruster performance requirements. The ion engine accumulated 2038 h of operation at a thruster input power of 6.9 kW, processing 43 kg of xenon. Overall ion engine performance, which includes thrust, thruster input power, specific impulse, and thrust efficiency, was steady with no indications of performance degradation. The ion engine was also inspected following the test. This paper presents these findings.

An Application-Based Performance Characterization of the Columbia Supercluster

NASA Technical Reports Server (NTRS)

Biswas, Rupak; Djomehri, Jahed M.; Hood, Robert; Jin, Hoaqiang; Kiris, Cetin; Saini, Subhash

2005-01-01

Columbia is a 10,240-processor supercluster consisting of 20 Altix nodes with 512 processors each, and currently ranked as the second-fastest computer in the world. In this paper, we present the performance characteristics of Columbia obtained on up to four computing nodes interconnected via the InfiniBand and/or NUMAlink4 communication fabrics. We evaluate floating-point performance, memory bandwidth, message passing communication speeds, and compilers using a subset of the HPC Challenge benchmarks, and some of the NAS Parallel Benchmarks including the multi-zone versions. We present detailed performance results for three scientific applications of interest to NASA, one from molecular dynamics, and two from computational fluid dynamics. Our results show that both the NUMAlink4 and the InfiniBand hold promise for application scaling to a large number of processors.

Physical phenomena in mercury ion thrusters

NASA Technical Reports Server (NTRS)

Wilbur, P. J.

1979-01-01

Experimental tests results demonstrating that reductions in screen grid thickness enhance the performance of ion thruster grids are presented. Shaping of the screen hole cross section is shown on the other hand not to affect performance substantially. The effect of the magnetic field in the vicinity of the hollow cathode on cathode performance is studied and test results are presented that show reductions in keeper voltages of a few volts can be realized by judicious applications of fields on the order of 100 gauss. The plasma downstream of a SERT 2 thruster operating without high voltage is studied. A model describing electron escape from the thruster under these conditions is discussed. A model defining the performance of the baffle aperture of an ion thruster is refined and experimental verification of the model is undertaken.

Surface Management System Departure Event Data Analysis

NASA Technical Reports Server (NTRS)

Monroe, Gilena A.

2010-01-01

This paper presents a data analysis of the Surface Management System (SMS) performance of departure events, including push-back and runway departure events.The paper focuses on the detection performance, or the ability to detect departure events, as well as the prediction performance of SMS. The results detail a modest overall detection performance of push-back events and a significantly high overall detection performance of runway departure events. The overall detection performance of SMS for push-back events is approximately 55%.The overall detection performance of SMS for runway departure events nears 100%. This paper also presents the overall SMS prediction performance for runway departure events as well as the timeliness of the Aircraft Situation Display for Industry data source for SMS predictions.

Team Pay for Performance: Experimental Evidence from Round Rock's Project on Incentives in Teaching

ERIC Educational Resources Information Center

McCaffrey, Daniel F.; Pane, John F.; Springer, Matthew G.; Burns, Susan F.; Haas, Ann

2011-01-01

This paper presents the results of a rigorous experiment examining the impact of pay for performance on student achievement and instructional practice. This study, conducted by the National Center on Performance Incentives, examines a pay-for-performance program in Round Rock (Texas) which distributed performance awards to teachers based on a…

Effects of visual and motion simulation cueing systems on pilot performance during takeoffs with engine failures

NASA Technical Reports Server (NTRS)

Parris, B. L.; Cook, A. M.

1978-01-01

Data are presented that show the effects of visual and motion during cueing on pilot performance during takeoffs with engine failures. Four groups of USAF pilots flew a simulated KC-135 using four different cueing systems. The most basic of these systems was of the instrument-only type. Visual scene simulation and/or motion simulation was added to produce the other systems. Learning curves, mean performance, and subjective data are examined. The results show that the addition of visual cueing results in significant improvement in pilot performance, but the combined use of visual and motion cueing results in far better performance.

Airbreathing Pulse Detonation Engine Performance

NASA Technical Reports Server (NTRS)

Povinelli, Louis A.; Yungster, Shaye

2002-01-01

This paper presents performance results for pulse detonation engines taking into account the effects of dissociation and recombination. The amount of sensible heat recovered through recombination in the PDE chamber and exhaust process was found to be significant. These results have an impact on the specific thrust, impulse and fuel consumption of the PDE.

A study of emissions from passenger cars in six cities. Volume B. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1979-01-01

This is the second of two volumes presenting results from a series of exhaust emission and fuel economy tests performed on a representative sample of vehicles in six U.S. cities. Data presented in the following sections are generated in appendix form as part of a contract with the EPA to perform work for the FY 77 Passenger Car Emission Factor Program. Volume B includes the balance of individual vehicle data derived from the Two Speed Idle and Federal Three Mode tests. It also includes the results of Vehicle Driveability Evaluations, Maladjustment and Disablement Inspections, tire inspections and a listing ofmore » comparative mileage data. Information presented in Volume B should not be interpreted without the benefit of additional descriptive data presented in Volume A as both volumes comprise the results of a single work effort and are not intended to be considered separately.« less

Concept for a Satellite-Based Advanced Air Traffic Management System : Volume 5. System Performance.

DOT National Transportation Integrated Search

1974-02-01

The volume presents the results of the performance evaluation of the Satellite-Based Advanced Air Traffic Management System (SAATMS). The evaluation established the capacity, safety, and delay performance of the system for the Los Angeles Basin termi...

Evaluation of the Trade Space Between UAS Maneuver Performance and SAA System Performance Requirements

NASA Technical Reports Server (NTRS)

Jack, Devin P.; Hoffler, Keith D.; Johnson, Sally C.

2014-01-01

A need exists to safely integrate Unmanned Aircraft Systems (UAS) into the National Airspace System. Replacing manned aircraft's see-and-avoid capability in the absence of an onboard pilot is one of the key challenges associated with safe integration. Sense-and-avoid (SAA) systems will have to achieve yet-to-be-determined required separation distances for a wide range of encounters. They will also need to account for the maneuver performance of the UAS they are paired with. The work described in this paper is aimed at developing an understanding of the trade space between UAS maneuver performance and SAA system performance requirements. An assessment of current manned and unmanned aircraft performance was used to establish potential UAS performance test matrix bounds. Then, nearterm UAS integration work was used to narrow down the scope. A simulator was developed with sufficient fidelity to assess SAA system performance requirements for a wide range of encounters. The simulator generates closest-point-of-approach (CPA) data from the wide range of UAS performance models maneuvering against a single intruder with various encounter geometries. The simulator is described herein and has both a graphical user interface and batch interface to support detailed analysis of individual UAS encounters and macro analysis of a very large set of UAS and encounter models, respectively. Results from the simulator using approximate performance data from a well-known manned aircraft is presented to provide insight into the problem and as verification and validation of the simulator. Analysis of climb, descent, and level turn maneuvers to avoid a collision is presented. Noting the diversity of backgrounds in the UAS community, a description of the UAS aerodynamic and propulsive design and performance parameters is included. Initial attempts to model the results made it clear that developing maneuver performance groups is required. Discussion of the performance groups developed and how to know in which group an aircraft belongs for a given flight condition and encounter is included. The groups are specific to airplane, flight condition, and encounter, rather than airplane-only specific. Results and methodology for developing UAS maneuver performance requirements are presented for each maneuver as well. Results for the vertical maneuver indicate that a minimum specific excess power value can assure a minimum CPA for a given time-to-go prediction. However, smaller values of specific excess power may achieve or exceed the same CPA if the UAS has sufficient speed to trade for altitude. Level turn results are less impacted by specific excess power and are presented as a function of turn rate. The effect of altitude is also discussed for the turns. Next steps and future work are discussed. Future studies will lead to better quantification of the preliminary results and cover the remainder of the proposed test matrix. It is anticipated that this will be done in conjunction with RTCA SC-228 over the next few months.

Performance deterioration based on existing (historical) data; JT9D jet engine diagnostics program

NASA Technical Reports Server (NTRS)

Sallee, G. P.

1978-01-01

The results of the collection and analysis of historical data pertaining to the deterioration of JT9D engine performance are presented. The results of analyses of prerepair and postrepair engine test stand performance data from a number of airlines to establish the individual as well as average losses in engine performance with respect to service use are included. Analysis of the changes in mechanical condition of parts, obtained by inspection of used gas-path parts of varying age, allowed preliminary assessments of component performance deterioration levels and identification of the causitive factors. These component performance estimates, refined by data from special engine back-to-back testing related to module performance restoration, permitted the development of preliminary models of engine component/module performance deterioration with respect to usage. The preliminary assessment of the causes of module performance deterioration and the trends with usage are explained, along with the role each module plays in overall engine performance deterioration. Preliminary recommendations with respect to operating and maintenance practices which could be adopted to control the level of performance deterioration are presented. The needs for additional component sensitivity testing as well as outstanding issues are discussed.

The influence of genetic polymorphisms on performance and cardiac and hemodynamic parameters among Brazilian soccer players.

PubMed

Dionísio, Thiago José; Thiengo, Carlos Rogério; Brozoski, Daniel Thomas; Dionísio, Evandro José; Talamoni, Guilherme Augusto; Silva, Roberto Braga; Garlet, Gustavo Pompermaier; Santos, Carlos Ferreira; Amaral, Sandra Lia

2017-06-01

This study investigated whether ACTN3 R577X, AMPD1 C34T, I/D ACE, and M235T AGT polymorphisms can affect performance tests such as jumping, sprinting, and endurance in 220 young male athletes from professional minor league soccer team from São Paulo Futebol Clube, Brazil. I/D ACE and M235T AGT polymorphisms were also analyzed according to cardiac and hemodynamic parameters. Athletes were grouped or not by age. DNA from saliva and Taqman assays were used for genotyping 220 athletes and the results were associated with performance tests. Ventricle mass, ventricle end-diastolic diameter, end-diastolic volume, and ejection fraction were assessed by echocardiogram. Arterial pressure, heart rate, and oximetry were assessed by a cardioscope. The main results of this study were that athletes who carried RR/RX (ACTN3) and DD (ACE) genotypes presented better performance during jump and sprint tests. On the other hand, athletes with ID/II genotype presented better results during endurance test, while AGT genotypes did not seem to favor the athletes during the evaluated physical tests. CC genotype (AMPD1) only favored the athletes during 10-m sprint test. Although there are environmental interactions influencing performance, the present results suggest that RR/RX ACTN3 and ACE DD genotypes may benefit athletes in activities that require strength and speed, while II ACE genotype may benefit athletes in endurance activities. This information could help coaches to plan the training session to improve the athletes' performance.

A practical tool for monitoring the performance of measuring systems in a laboratory network: report of an ACB Working Group.

PubMed

Ayling, Pete; Hill, Robert; Jassam, Nuthar; Kallner, Anders; Khatami, Zahra

2017-11-01

Background A logical consequence of the introduction of robotics and high-capacity analysers has seen a consolidation to larger units. This requires new structures and quality systems to ensure that laboratories deliver consistent and comparable results. Methods A spreadsheet program was designed to accommodate results from up to 12 different instruments/laboratories and present IQC data, i.e. Levey-Jennings and Youden plots and comprehensive numerical tables of the performance of each item. Input of data was made possible by a 'data loader' by which IQC data from the individual instruments could be transferred to the spreadsheet program on line. Results A set of real data from laboratories is used to populate the data loader and the networking software program. Examples are present from the analysis of variance components, the Levey-Jennings and Youden plots. Conclusions This report presents a software package that allows the simultaneous management and detailed monitoring of the performance of up to 12 different instruments/laboratories in a fully interactive mode. The system allows a quality manager of networked laboratories to have a continuous updated overview of the performance. This software package has been made available at the ACB website.

Prospective memory across adolescence: the effects of age and cue focality.

PubMed

Wang, Lijuan; Altgassen, Mareike; Liu, Wei; Xiong, Weirui; Akgün, Canan; Kliegel, Matthias

2011-01-01

The present study examined the role of controlled attention in age differences in event-based prospective memory performance across adolescence. The researchers tested whether presenting the prospective memory cue in or out of focal awareness of the ongoing task (resulting in low versus high demands for controlled attention, respectively) might affect age-related prospective memory performance. In total, 119 Chinese participants ages 13 to 20 took part in this study (60 adolescents: age M = 13.26 years, SD = 0.50; 23 boys; 59 young adults: age M = 19.70 years, SD = 0.87; 19 men). Findings demonstrated a significant interaction, F(1, 114) = 6.41, p < .05. No effect of age on prospective memory performance was revealed when a focal cue was used (F < 1), whereas there was a reliable age effect between adolescents and young adults when nonfocal prospective memory cues were presented, F(1, 59) = 16.13, p < .01. This pattern of results suggests that the interplay of both available resources of controlled attention and working memory, along with specific task demands, may contribute to possible age differences in prospective memory performance across adolescence. Results are discussed in the context of the multiprocess theory of prospective memory.

Sex differences in verbal and visual-spatial tasks under different hemispheric visual-field presentation conditions.

PubMed

Boyle, Gregory J; Neumann, David L; Furedy, John J; Westbury, H Rae

2010-04-01

This paper reports sex differences in cognitive task performance that emerged when 39 Australian university undergraduates (19 men, 20 women) were asked to solve verbal (lexical) and visual-spatial cognitive matching tasks which varied in difficulty and visual field of presentation. Sex significantly interacted with task type, task difficulty, laterality, and changes in performance across trials. The results revealed that the significant individual-differences' variable of sex does not always emerge as a significant main effect, but instead in terms of significant interactions with other variables manipulated experimentally. Our results show that sex differences must be taken into account when conducting experiments into human cognitive-task performance.

Performance evaluation of the use of photovoltaics to power a street light in Lowell

NASA Astrophysics Data System (ADS)

Crowell, Adam B.

Commercial, off-grid photovoltaic (PV) lighting systems present an attractive alternative to traditional outdoor lighting at sites where grid power is unavailable or unreliable. This study presents a comprehensive theoretical site analysis for the installation of standalone PV lighting systems at the Lowell National Historic Park in Lowell, MA. Detailed insolation studies are performed at the target site, resulting in expected daily Watt-hour totals available for battery charging for each month of the year. Illumination simulations are presented, detailing the expected lighting performance of the systems at night. Light levels are compared to those dictated by accepted standards. While it is acknowledged that the target site presents significant challenges to photovoltaics, such as severe shading, final system component specifications are provided, along with programming and positioning recommendations that will yield the best achievable performance.

Flight Stability and Control and Performance Results from the Linear Aerospike SR-71 Experiment (LASRE)

NASA Technical Reports Server (NTRS)

Moes, Timothy R.; Cobleigh, Brent R.; Cox, Timothy H.; Conners, Timothy R.; Iliff, Kenneth W.; Powers, Bruce G.

1998-01-01

The Linear Aerospike SR-71 Experiment (LASRE) is presently being conducted to test a 20-percent-scale version of the Linear Aerospike rocket engine. This rocket engine has been chosen to power the X-33 Single Stage to Orbit Technology Demonstrator Vehicle. The rocket engine was integrated into a lifting body configuration and mounted to the upper surface of an SR-71 aircraft. This paper presents stability and control results and performance results from the envelope expansion flight tests of the LASRE configuration up to Mach 1.8 and compares the results with wind tunnel predictions. Longitudinal stability and elevator control effectiveness were well-predicted from wind tunnel tests. Zero-lift pitching moment was mispredicted transonically. Directional stability, dihedral stability, and rudder effectiveness were overpredicted. The SR-71 handling qualities were never significantly impacted as a result of the missed predictions. Performance results confirmed the large amount of wind-tunnel-predicted transonic drag for the LASRE configuration. This drag increase made the performance of the vehicle so poor that acceleration through transonic Mach numbers could not be achieved on a hot day without depleting the available fuel.

Executive Function and Children's Understanding of False Belief: How Specific Is the Relation?

ERIC Educational Resources Information Center

Muller, U.; Zelazo, P.D.; Imrisek, S.

2005-01-01

The present study examined developmental relations among understanding false belief, understanding ''false'' photographs, performance on the Dimensional Change Card Sort (DCCS), and performance on a picture-sentence verification task in 69 3-5-year-old children. Results showed that performance on the DCCS predicted performance on false belief…

Theoretical performance of cross-wind axis turbines with results for a catenary vertical axis configuration

NASA Technical Reports Server (NTRS)

Muraca, R. J.; Stephens, M. V.; Dagenhart, J. R.

1975-01-01

A general analysis capable of predicting performance characteristics of cross-wind axis turbines was developed, including the effects of airfoil geometry, support struts, blade aspect ratio, windmill solidity, blade interference and curved flow. The results were compared with available wind tunnel results for a catenary blade shape. A theoretical performance curve for an aerodynamically efficient straight blade configuration was also presented. In addition, a linearized analytical solution applicable for straight configurations was developed. A listing of the computer program developed for numerical solutions of the general performance equations is included in the appendix.

Analysis of link performance for the FOENEX laser communications system

NASA Astrophysics Data System (ADS)

Juarez, Juan C.; Young, David W.; Venkat, Radha A.; Brown, David M.; Brown, Andrea M.; Oberc, Rachel L.; Sluz, Joseph E.; Pike, H. Alan; Stotts, Larry B.

2012-06-01

A series of experiments were conducted to validate the performance of the free-space optical communications (FSOC) subsystem under DARPA's FOENEX program. Over six days, bidirectional links at ranges of 10 and 17 km were characterized during different periods of the day to evaluate link performance. This paper will present the test configuration, evaluate performance of the FSOC subsystem against a variety of characterization approaches, and discuss the impact of the results, particularly with regards to the optical terminals. Finally, this paper will summarize the impact of turbulence conditions on the FSOC subsystem and present methods for estimating performance under different link distances and turbulence conditions.

Reservoir studies with geostatistics to forecast performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, R.W.; Behrens, R.A.; Emanuel, A.S.

1991-05-01

In this paper example geostatistics and streamtube applications are presented for waterflood and CO{sub 2} flood in two low-permeability sandstone reservoirs. Thy hybrid approach of combining fine vertical resolution in cross-sectional models with streamtubes resulted in models that showed water channeling and provided realistic performance estimates. Results indicate that the combination of detailed geostatistical cross sections and fine-grid streamtube models offers a systematic approach for realistic performance forecasts.

HPF Implementation of ARC3D

NASA Technical Reports Server (NTRS)

Frumkin, Michael; Yan, Jerry

1999-01-01

We present an HPF (High Performance Fortran) implementation of ARC3D code along with the profiling and performance data on SGI Origin 2000. Advantages and limitations of HPF as a parallel programming language for CFD applications are discussed. For achieving good performance results we used the data distributions optimized for implementation of implicit and explicit operators of the solver and boundary conditions. We compare the results with MPI and directive based implementations.

Measurement of health system performance at district level: A study protocol

PubMed Central

Sharma, Atul; Prinja, Shankar; Aggarwal, Arun Kumar

2018-01-01

Background Limited efforts have been observed in low and middle income countries to undertake health system performance assessment at district level. Absence of a comprehensive data collection tool and lack of a standardised single summary measure defining overall performance are some of the main problems. Present study has been undertaken to develop a summary composite health system performance index at district level. Methods A broad range of indicators covering all six domains as per building block framework were finalized by an expert panel. The domains were classified into twenty sub-domains, with 70 input and process indicators to measure performance. Seven sub-domains for assessing health system outputs and outcomes were identified, with a total of 28 indicators. Districts in Haryana state from north India were selected for the study. Primary and secondary data will be collected from 378 health facilities, district and state health directorate headquarters. Indicators will be normalized, aggregated to generate composite performance index at district level. Domain specific scores will present the quality of individual building block domains in the public health system. Robustness of the results will be checked using sensitivity analysis. Expected impact for public health: The study presents a methodology for comprehensive assessment of all health system domains on basis of input, process, output and outcome indicators which has never been reported from India. Generation of this index will help identify policy and implementation areas of concern and point towards potential solutions. Results may also help understand relationships between individual building blocks and their sub-components. Significance for public health Measuring performance of health system is important to understand progress and challenges, and create systems that are efficient, equitable and patient-focused. However, very few assessments of such nature have been observed in low and middle income countries, especially at district level, mainly because of methodological challenges. This study presents a methodology for comprehensive assessment of all domains of health system and generation of a composite Health System Performance Index on the basis of input, process, output and outcome indicators. It will help identify policy and implementation problems worthy of attention and point towards potential solutions to health system bottlenecks resulting in poor performance. The results may also help better understand the relationships between individual building blocks and their sub-components and the overall performance of the health system. PMID:29441330

Results of the 1978 NACUBO Comparative Performance Study and Investment Questionnaire.

ERIC Educational Resources Information Center

Dresner, Bruce M.

Information from the 1978 Comparative Performance Study and investment questionnaire conducted by the National Association of College and University Business Officers is presented. One hundred forty-four institutions provided information about 164 investment pools. The Comparative Performance Study provides participating institutions with…

A two-dimensional cascade solution using minimized surface singularity density distributions - with application to film cooled turbine blades

NASA Technical Reports Server (NTRS)

Mcfarland, E.; Tabakoff, W.; Hamed, A.

1977-01-01

An investigation of the effects of coolant injection on the aerodynamic performance of cooled turbine blades is presented. The coolant injection is modeled in the inviscid irrotational adiabatic flow analysis through the cascade using the distributed singularities approach. The resulting integral equations are solved using a minimized surface singularity density criteria. The aerodynamic performance was evaluated using this solution in conjunction with an existing mixing theory analysis. The results of the present analysis are compared with experimental measurements in cold flow tests.

OARE STS-78 (LMS-1) Final Report

NASA Technical Reports Server (NTRS)

Rice, James E.

1996-01-01

The report is organized into sections representing the phases of work performed in analyzing the STS-78 (LMS-1) results. Section 1 briefly outlines the Orbital Acceleration Research Experiment (OARE) system features, coordinates, and measurement parameters. Section 2 describes the results from STS-78. The mission description, data calibration, and representative data obtained on STS-78 are presented. Also, the anomalous performance of OARE on STS-78 is discussed. Finally, Section 3 presents a discussion of accuracy achieved and achievable with OARE. Appendix A discusses the data processing methodology in detail.

Characterization of a space orbited incoherent fiber optic bundle

NASA Technical Reports Server (NTRS)

Dewalt, Stephen A.; Taylor, Edward W.

1993-01-01

The results of a study performed to determine the effects of adverse space environments on a bundle of over 1800 optical fibers orbited for 69 months are reported. Experimental results are presented on an incoherent fiber optic bundle oriented in low Earth orbit aboard the Long Duration Exposure Facility (LDEF) satellite as part of the Space Environment Effects Experiment (M0006). Measurements were performed to determine if space induced radiation effects changed the fiber bundle characteristics. Data demonstrating the success of light transmitting fibers to withstand the adverse space environment are presented.

Update on the Fabrication and Performance of 2-D Arrays of Superconducting Magnesium Diboride (MgB2) Thermal Detectors for Outer-Planets Exploration

NASA Technical Reports Server (NTRS)

Lakew, Brook; Aslam, S.

2011-01-01

Detectors with better performance than the current thermopile detectors that operate at room temperature will be needed at the focal plane of far-infrared instruments on future planetary exploration missions. We will present an update on recent results from the 2-D array of MgB2 thermal detectors being currently developed at NASA Goddard. Noise and sensitivity results will be presented and compared to thermal detectors currently in use on planetary missions.

The effect of alcohol blends on the performance of an air cooled Rotary Trochoidal Engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gutman, M.; Iuster, I.

Results obtained from tests on an air cooled Rotary Trochoidal Engine fueled with a gasoline-alcohol mixture, without modification of the carburetor, are presented in this paper. The tests were performed with one and two spark plugs. Amongst the obtained results, lower thermal load, better economy and improvement in cycling uniformity when running with two spark plugs were observed. The observed reduction in the rotor housing wall temperature and in the oil sump temperature presents particular advantages for an air cooled engine.

The effect of alcohol blends on the performance of an air cooled rotary trochoidal engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gutman, M.; Iuster, I.

Results obtained from tests on an air cooled Rotary Trochoidal Engine fueled with a gasoline-alcohol mixture, without modification of the carburetor, are presented in this paper. The tests were performed with one and two spark plugs. Amongst the obtained results, lower thermal load, better economy and improvement in cycling uniformity when running with two spark plugs were observed. The observed reduction in the rotor housing wall temperature and in the oil sump temperature presents particular advantages for an air cooled engine.

Experimental evaluation of a 600 lbf spacecraft rocket engine.

NASA Technical Reports Server (NTRS)

Hoehn, F. W.

1972-01-01

Experimental results are presented for a long-duration-capability (1000-sec), space-storable, bipropellant liquid rocket motor burning fluorine/hydrazine or FLOX/monomethylhydrazine. The interrelationship between injected mixture ratio and the per cent film cooling on vacuum specific impulse performance and chamber heat transfer is given. Experimental sea level measurements are used to predict space vacuum performance based upon simplified JANNAF reference procedures. Dynamic combustion stability is demonstrated over a wide range of operating conditions. Analytical results of char penetration, erosion, and ablative wall temperature distributions are presented for prototype chamber designs.

Social presence and the composite face effect.

PubMed

Garcia-Marques, Teresa; Fernandes, Alexandre; Fonseca, Ricardo; Prada, Marilia

2015-06-01

A robust finding in social psychology research is that performance is modulated by the social nature of a given context, promoting social inhibition or facilitation effects. In the present experiment, we examined if and how social presence impacts holistic face perception processes by asking participants, in the presence of others and alone, to perform the composite face task. Results suggest that completing the task in the presence of others (i.e., mere co-action) is associated with better performance in face recognition (less bias and higher discrimination between presented and non-presented targets) and with a reduction in the composite face effect. These results make clear that social presence impact on the composite face effect does not occur because presence increases reliance on holistic processing as a "dominant" well-learned response, but instead, because it increases monitoring of the interference produced by automatic response. Copyright © 2015. Published by Elsevier B.V.

Characterizing Detonating LX-17 Charges Crossing a Transverse Air Gap with Experiments and Modeling

NASA Astrophysics Data System (ADS)

Lauderbach, Lisa M.; Souers, P. Clark; Garcia, Frank; Vitello, Peter; Vandersall, Kevin S.

2009-06-01

Experiments were performed using detonating LX-17 (92.5% TATB, 7.5% Kel-f by weight) charges with various width transverse air gaps both with and without manganin peizoresistive in-situ gauges present. The experiments, performed with 25 mm diameter by 25 mm long LX-17 pellets with the transverse air gap in between, showed that transverse gaps up to about 3 mm could be present without causing the detonation wave to fail to continue as a detonation. A JWL++/Tarantula code was utilized to model the results and compare with the in-situ gauge records with reasonable agreement to the experimental data. This work will present the experimental details as well as comparison to the model results. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Final Report - IHLW PCT, Spinel T1%, Electrical Conductivity, and Viscosity Model Development, VSL-07R1240-4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.; Piepel, Gregory F.; Landmesser, S. M.

2013-11-13

This report is the last in a series of currently scheduled reports that presents the results from the High Level Waste (HLW) glass formulation development and testing work performed at the Vitreous State Laboratory (VSL) of the Catholic University of America (CUA) and the development of IHLW property-composition models performed jointly by Pacific Northwest National Laboratory (PNNL) and VSL for the River Protection Project-Waste Treatment and Immobilization Plant (RPP-WTP). Specifically, this report presents results of glass testing at VSL and model development at PNNL for Product Consistency Test (PCT), one-percent crystal fraction temperature (T1%), electrical conductivity (EC), and viscosity ofmore » HLW glasses. The models presented in this report may be augmented and additional validation work performed during any future immobilized HLW (IHLW) model development work. Completion of the test objectives is addressed.« less

The noncavitating performance and life of a small vane-type positive displacement pump in liquid hydrogen

NASA Technical Reports Server (NTRS)

Ulbricht, T. E.; Hemminger, J. A.

1986-01-01

The low flow rate and high head rise requirements of hydrogen/oxygen auxiliary propulsion systems make the application of centrifugal pumps difficult. Positive displacement pumps are well-suited for these flow conditions, but little is known about their performance and life characteristics in liquid hydrogen. An experimental and analytical investigation was conducted to determine the performance and life characteristics of a vane-type, positive displacement pump. In the experimental part of this effort, mass flow rate and shaft torque were determined as functions of shaft speed and pump pressure rise. Since liquid hydrogen offers little lubrication in a rubbing situation, pump life is an issue. During the life test, the pump was operated intermittently for 10 hr at the steady-state point of 0.074 lbm/sec (0.03 kg/sec) flow rate, 3000 psid (2.07 MPa) pressure rise, and 8000 rpm (838 rad/sec) shaft speed. Pump performance was monitored during the life test series and the results indicated no loss in performance. Material loss from the vanes was recorded and wear of the other components was documented. In the analytical part of this effort, a comprehensive pump performance analysis computer code, developed in-house, was used to predict pump performance. The results of the experimental investigation are presented and compared with the results of the analysis. Results of the life test are also presented.

WRF-Cordex simulations for Europe: mean and extreme precipitation for present and future climates

NASA Astrophysics Data System (ADS)

Cardoso, Rita M.; Soares, Pedro M. M.; Miranda, Pedro M. A.

2013-04-01

The Weather Research and Forecast (WRF-ARW) model, version 3.3.1, was used to perform the European domain Cordex simulations, at 50km resolution. A first simulation, forced by ERA-Interim (1989-2009), was carried out to evaluate the models performance to represent the mean and extreme precipitation in present European climate. This evaluation is based in the comparison of WRF results against the ECAD regular gridded dataset of daily precipitation. Results are comparable to recent studies with other models for the European region, at this resolution. For the same domain a control and a future scenario (RCP8.5) simulation was performed to assess the climate change impact on the mean and extreme precipitation. These regional simulations were forced by EC-EARTH model results, and, encompass the periods from 1960-2006 and 2006-2100, respectively.

Electron bunch energy and phase feed-forward stabilization system for the Mark V RF-linac free-electron laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hadmack, M. R.; Kowalczyk, J. M. D.; Lienert, B. R.

2013-06-15

An amplitude and phase compensation system has been developed and tested at the University of Hawai'i for the optimization of the RF drive system to the Mark V free-electron laser. Temporal uniformity of the RF drive is essential to the generation of an electron beam suitable for optimal free-electron laser performance and the operation of an inverse Compton scattering x-ray source. The design of the RF measurement and compensation system is described in detail and the results of RF phase compensation are presented. Performance of the free-electron laser was evaluated by comparing the measured effects of phase compensation with themore » results of a computer simulation. Finally, preliminary results are presented for the effects of amplitude compensation on the performance of the complete system.« less

Comparison of Analytical Predictions and Experimental Results for a Dual Brayton Power System

NASA Technical Reports Server (NTRS)

Johnson, Paul

2007-01-01

NASA Glenn Research Center (GRC) contracted Barber- Nichols, Arvada, CO to construct a dual Brayton power conversion system for use as a hardware proof of concept and to validate results from a computational code known as the Closed Cycle System Simulation (CCSS). Initial checkout tests were performed at Barber- Nichols to ready the system for delivery to GRC. This presentation describes the system hardware components and lists the types of checkout tests performed along with a couple issues encountered while conducting the tests. A description of the CCSS model is also presented. The checkout tests did not focus on generating data, therefore, no test data or model analyses are presented.

Airbreathing Pulse Detonation Engine Performance

NASA Technical Reports Server (NTRS)

Povinelli, Louis A.; Yungster, Shaye

2002-01-01

This paper presents performance results for pulse detonation engines (PDE) taking into account the effects of dissociation and recombination. The amount of sensible heat recovered through recombination in the PDE chamber and exhaust process was found to be significant. These results have an impact on the specific thrust, impulse and fuel consumption of the PDE.

Characterization of DBD Plasma Actuators Performance Without External Flow - Part I: Thrust-Voltage Quadratic Relationship in Logarithmic Space for Sinusoidal Excitation

NASA Technical Reports Server (NTRS)

Ashpis, David E.; Laun, Matthew C.

2016-01-01

Results of characterization of Dielectric Barrier Discharge (DBD) plasma actuators without external flow are presented. The results include aerodynamic and electric performance of the actuators without external flow for different geometrical parameters, dielectric materials and applied voltage level and wave form.

Development of Flight-Test Performance Estimation Techniques for Small Unmanned Aerial Systems

NASA Astrophysics Data System (ADS)

McCrink, Matthew Henry

This dissertation provides a flight-testing framework for assessing the performance of fixed-wing, small-scale unmanned aerial systems (sUAS) by leveraging sub-system models of components unique to these vehicles. The development of the sub-system models, and their links to broader impacts on sUAS performance, is the key contribution of this work. The sub-system modeling and analysis focuses on the vehicle's propulsion, navigation and guidance, and airframe components. Quantification of the uncertainty in the vehicle's power available and control states is essential for assessing the validity of both the methods and results obtained from flight-tests. Therefore, detailed propulsion and navigation system analyses are presented to validate the flight testing methodology. Propulsion system analysis required the development of an analytic model of the propeller in order to predict the power available over a range of flight conditions. The model is based on the blade element momentum (BEM) method. Additional corrections are added to the basic model in order to capture the Reynolds-dependent scale effects unique to sUAS. The model was experimentally validated using a ground based testing apparatus. The BEM predictions and experimental analysis allow for a parameterized model relating the electrical power, measurable during flight, to the power available required for vehicle performance analysis. Navigation system details are presented with a specific focus on the sensors used for state estimation, and the resulting uncertainty in vehicle state. Uncertainty quantification is provided by detailed calibration techniques validated using quasi-static and hardware-in-the-loop (HIL) ground based testing. The HIL methods introduced use a soft real-time flight simulator to provide inertial quality data for assessing overall system performance. Using this tool, the uncertainty in vehicle state estimation based on a range of sensors, and vehicle operational environments is presented. The propulsion and navigation system models are used to evaluate flight-testing methods for evaluating fixed-wing sUAS performance. A brief airframe analysis is presented to provide a foundation for assessing the efficacy of the flight-test methods. The flight-testing presented in this work is focused on validating the aircraft drag polar, zero-lift drag coefficient, and span efficiency factor. Three methods are detailed and evaluated for estimating these design parameters. Specific focus is placed on the influence of propulsion and navigation system uncertainty on the resulting performance data. Performance estimates are used in conjunction with the propulsion model to estimate the impact sensor and measurement uncertainty on the endurance and range of a fixed-wing sUAS. Endurance and range results for a simplistic power available model are compared to the Reynolds-dependent model presented in this work. Additional parameter sensitivity analysis related to state estimation uncertainties encountered in flight-testing are presented. Results from these analyses indicate that the sub-system models introduced in this work are of first-order importance, on the order of 5-10% change in range and endurance, in assessing the performance of a fixed-wing sUAS.

Road weather management performance metrics.

DOT National Transportation Integrated Search

2008-04-29

This report presents the results of a study to identify appropriate measures of performance that can be attributed to the Federal Highway Administrations (FHWA) Road Weather Management Program (RWMP) products and activities. Specifically, the stud...

Common pressure vessel battery performance

NASA Technical Reports Server (NTRS)

Otzinger, B.

1978-01-01

Performance tests run on two common pressure vessel type nickel hydrogen batteries are described and the results presented. The study included: (1) charge retention tests, (2) synchronous eclipse season cycling tests, and (3) temperature differential tests.

The effect of bridge exercise accompanied by the abdominal drawing-in maneuver on an unstable support surface on the lumbar stability of normal adults.

PubMed

Gong, Wontae

2015-01-01

[Purpose] The present study sought to investigate the influence on static and dynamic lumbar stability of bridge exercise accompanied by an abdominal drawing-in maneuver (ADIM) performed on an uneven support surface. [Subjects] A total of 30 participants were divided into an experimental group (15 participants) and a control group (15 participants). [Methods] The experimental group performed bridge exercise on an unstable surface, whereas the control group performed bridge exercise on a stable surface. The respective bridge exercises were performed for 30 minutes, 3 times per week, for 6 weeks. The static lumbar stability (SLS) and dynamic lumbar stability (DLS) of both the experimental group and the control group were measured using a pressure biofeedback unit. [Results] In the comparison of the initial and final results of the experimental and control groups, only the SLS and DLS of the experimental group were found to be statistically significant. [Conclusion] The results of the present study show that when using bridge exercise to improve SLS and DLS, performing the bridge exercise accompanied by ADIM on an uneven surface is more effective than performing the exercise on a stable surface.

Wideband 1.064 micrometer detector evaluation

NASA Technical Reports Server (NTRS)

Green, S. I.

1975-01-01

The performance of several candidate detectors for use as communications detectors in a 400 Mbps 1.064 micrometers laser communication system was evaluated. The results of communication system Bit Error Rate (BER) testing for the best detector of each type are summarized. Complete testing data of each type detector is presented. The 400 Mbps 1.064 micrometers communication system receiver test bed is described. The best communication system results for each detector type are included. Performance comparisons are made at 0.000001 BER, the specification level chosen for satellite laser communication links. The data is presented in two groups. The first indicates the best performance levels that can be expected on normal space laser communication system operation. The second cites the best performance levels which can be achieved by focusing the signal to diffraction limited spots on the photosensitive area.

Intracavity adaptive optics. 1: Astigmatism correction performance.

PubMed

Spinhirne, J M; Anafi, D; Freeman, R H; Garcia, H R

1981-03-15

A detailed experimental study has been conducted on adaptive optical control methodologies inside a laser resonator. A comparison is presented of several optimization techniques using a multidither zonal coherent optical adaptive technique system within a laser resonator for the correction of astigmatism. A dramatic performance difference is observed when optimizing on beam quality compared with optimizing on power-in-the-bucket. Experimental data are also presented on proper selection criteria for dither frequencies when controlling phase front errors. The effects of hardware limitations and design considerations on the performance of the system are presented, and general conclusions and physical interpretations on the results are made when possible.

Optimization of a matched-filter receiver for frequency hopping code acquisition in jamming

NASA Astrophysics Data System (ADS)

Pawlowski, P. R.; Polydoros, A.

A matched-filter receiver for frequency hopping (FH) code acquisition is optimized when either partial-band tone jamming or partial-band Gaussian noise jamming is present. The receiver is matched to a segment of the FH code sequence, sums hard per-channel decisions to form a test, and uses multiple tests to verify acquisition. The length of the matched filter and the number of verification tests are fixed. Optimization is then choosing thresholds to maximize performance based upon the receiver's degree of knowledge about the jammer ('side-information'). Four levels of side-information are considered, ranging from none to complete. The latter level results in a constant-false-alarm-rate (CFAR) design. At each level, performance sensitivity to threshold choice is analyzed. Robust thresholds are chosen to maximize performance as the jammer varies its power distribution, resulting in simple design rules which aid threshold selection. Performance results, which show that optimum distributions for the jammer power over the total FH bandwidth exist, are presented.

Spectrum Sharing in an ISM Band: Outage Performance of a Hybrid DS/FH Spread Spectrum System with Beamforming

NASA Astrophysics Data System (ADS)

Li, Hanyu; Syed, Mubashir; Yao, Yu-Dong; Kamakaris, Theodoros

2009-12-01

This paper investigates spectrum sharing issues in the unlicensed industrial, scientific, and medical (ISM) bands. It presents a radio frequency measurement setup and measurement results in 2.4 GHz. It then develops an analytical model to characterize the coexistence interference in the ISM bands, based on radio frequency measurement results in the 2.4 GHz. Outage performance using the interference model is examined for a hybrid direct-sequence frequency-hopping spread spectrum system. The utilization of beamforming techniques in the system is also investigated, and a simplified beamforming model is proposed to analyze the system performance using beamforming. Numerical results show that beamforming significantly improves the system outage performance. The work presented in this paper provides a quantitative evaluation of signal outages in a spectrum sharing environment. It can be used as a tool in the development process for future dynamic spectrum access models as well as engineering designs for applications in unlicensed bands.

Logo recognition using alpha-rooted phase correlation in the radon transform domain

NASA Astrophysics Data System (ADS)

DelMarco, Stephen

2009-08-01

Alpha-rooted phase correlation (ARPC) is a recently-developed variant of classical phase correlation that includes a Fourier domain image enhancement operation. ARPC combines classical phase correlation with alpha-rooting to provide tunable image enhancement. The alpha-rooting parameters may be adjusted to provide a tradeoff between height and width of the ARPC main lobe. A high narrow main lobe peak provides high matching accuracy for aligned images, but reduced matching performance for misaligned logos. A lower, wider peak trades matching accuracy on aligned logos, for improved matching performance on misaligned imagery. Previously, we developed ARPC and used it in the spatial domain for logo recognition as part of an overall automated document analysis problem. However, spatial domain ARPC performance can be sensitive to logo misalignments, including rotational misalignment. In this paper we use ARPC as a match metric in the radon transform domain for logo recognition. In the radon transform domain, rotational misalignments correspond to translations in the radon transform angle parameter. These translations are captured by ARPC, thereby producing rotation-invariant logo matching. In the paper, we first present an overview of ARPC, and then describe the logo matching algorithm. We present numerical performance results demonstrating matching tolerance to rotational misalignments. We demonstrate robustness of the radon transform domain rotation estimation to noise. We present logo verification and recognition performance results using the proposed approach on a public domain logo database. We compare performance results to performance obtained using spatial domain ARPC, and state-of-the-art SURF features, for logos in salt-and-pepper noise.

Errors on interrupter tasks presented during spatial and verbal working memory performance are linearly linked to large-scale functional network connectivity in high temporal resolution resting state fMRI.

PubMed

Magnuson, Matthew Evan; Thompson, Garth John; Schwarb, Hillary; Pan, Wen-Ju; McKinley, Andy; Schumacher, Eric H; Keilholz, Shella Dawn

2015-12-01

The brain is organized into networks composed of spatially separated anatomical regions exhibiting coherent functional activity over time. Two of these networks (the default mode network, DMN, and the task positive network, TPN) have been implicated in the performance of a number of cognitive tasks. To directly examine the stable relationship between network connectivity and behavioral performance, high temporal resolution functional magnetic resonance imaging (fMRI) data were collected during the resting state, and behavioral data were collected from 15 subjects on different days, exploring verbal working memory, spatial working memory, and fluid intelligence. Sustained attention performance was also evaluated in a task interleaved between resting state scans. Functional connectivity within and between the DMN and TPN was related to performance on these tasks. Decreased TPN resting state connectivity was found to significantly correlate with fewer errors on an interrupter task presented during a spatial working memory paradigm and decreased DMN/TPN anti-correlation was significantly correlated with fewer errors on an interrupter task presented during a verbal working memory paradigm. A trend for increased DMN resting state connectivity to correlate to measures of fluid intelligence was also observed. These results provide additional evidence of the relationship between resting state networks and behavioral performance, and show that such results can be observed with high temporal resolution fMRI. Because cognitive scores and functional connectivity were collected on nonconsecutive days, these results highlight the stability of functional connectivity/cognitive performance coupling.

Performance Testing of a Trace Contaminant Control Subassembly for the International Space Station

NASA Technical Reports Server (NTRS)

Perry, J. L.; Curtis, R. E.; Alexandre, K. L.; Ruggiero, L. L.; Shtessel, N.

1998-01-01

As part of the International Space Station (ISS) Trace Contaminant Control Subassembly (TCCS) development, a performance test has been conducted to provide reference data for flight verification analyses. This test, which used the U.S. Habitation Module (U.S. Hab) TCCS as the test article, was designed to add to the existing database on TCCS performance. Included in this database are results obtained during ISS development testing; testing of functionally similar TCCS prototype units; and bench scale testing of activated charcoal, oxidation catalyst, and granular lithium hydroxide (LiOH). The present database has served as the basis for the development and validation of a computerized TCCS process simulation model. This model serves as the primary means for verifying the ISS TCCS performance. In order to mitigate risk associated with this verification approach, the U.S. Hab TCCS performance test provides an additional set of data which serve to anchor both the process model and previously-obtained development test data to flight hardware performance. The following discussion provides relevant background followed by a summary of the test hardware, objectives, requirements, and facilities. Facility and test article performance during the test is summarized, test results are presented, and the TCCS's performance relative to past test experience is discussed. Performance predictions made with the TCCS process model are compared with the U.S. Hab TCCS test results to demonstrate its validation.

Contribution to the Performance Determination of Microjets. Ph.D. Thesis - Technical Univ., Feb. 1983

NASA Technical Reports Server (NTRS)

Hayn, D.

1984-01-01

Theoretical investigations are made on the performance of microjets. A description is given of experiments with micropropulsion units to correlate the results obtained in the first part of the report. Execution of performance measurements is discussed, and error calculations are presented.

Evaluation and Application of Enhancements to the Performance of the ASDE-3 Radar in Heavy Rain

DOT National Transportation Integrated Search

1982-03-01

This report presents the results of a study performed by the Transportation Systems Center (TSC) to evaluate two proposed enhancements to the performance of the ASDE-3 Radar in heavy rain: Adaptive gain and adaptive clutter thresholding, (operating w...

PERMEABLE REACTIVE BARRIER PERFORMANCE MONITORING: LONG-TERM TRENDS IN GEOCHEMICAL PARAMETERS AT TWO SITES

EPA Science Inventory

A major goal of research on the long-term performance of subsurface reactive barriers is to identify standard ground water monitoring parameters that may be useful indicators of declining performance or impending system failure. Results are presented from ground water monitoring ...

PERMEABLE REACTIVE BARRIER PERFORMANCE MONITORING: LONG-TERM TRENDS IN GEOCHEMICAL PARAMETERS AT TWO SITES

EPA Science Inventory

A major goal of research on the long-term performance of subsurface reactive barriers is to identify standard ground-water monitoring parameters that may be useful indicators of declining performance or impending system failure. Results are presented from studies conducted over ...

Postlingual adult performance in noise with HiRes 120 and ClearVoice Low, Medium, and High.

PubMed

Holden, Laura K; Brenner, Christine; Reeder, Ruth M; Firszt, Jill B

2013-11-01

The study's objectives were to evaluate speech recognition in multiple listening conditions using several noise types with HiRes 120 and ClearVoice (Low, Medium, High) and to determine which ClearVoice program was most beneficial for everyday use. Fifteen postlingual adults attended four sessions; speech recognition was assessed at sessions 1 and 3 with HiRes 120 and at sessions 2 and 4 with all ClearVoice programs. Test measures included sentences presented in restaurant noise (R-SPACE), in speech-spectrum noise, in four- and eight-talker babble, and connected discourse presented in 12-talker babble. Participants completed a questionnaire comparing ClearVoice programs. Significant group differences in performance between HiRes 120 and ClearVoice were present only in the R-SPACE; performance was better with ClearVoice High than HiRes 120. Among ClearVoice programs, no significant group differences were present for any measure. Individual results revealed most participants performed better in the R-SPACE with ClearVoice than HiRes 120. For other measures, significant individual differences between HiRes 120 and ClearVoice were not prevalent. Individual results among ClearVoice programs differed and overall preferences varied. Questionnaire data indicated increased understanding with High and Medium in certain environments. R-SPACE and questionnaire results indicated an advantage for ClearVoice High and Medium. Individual test and preference data showed mixed results between ClearVoice programs making global recommendations difficult; however, results suggest providing ClearVoice High and Medium and HiRes 120 as processor options for adults willing to change settings. For adults unwilling or unable to change settings, ClearVoice Medium is a practical choice for daily listening.

Advanced 35 W Free-Piston Stirling Engine for Space Power Applications

NASA Astrophysics Data System (ADS)

Wood, J. Gary; Lane, Neill

2003-01-01

This paper presents the projected performance and overall design characteristics of a high efficiency, low mass 35 W free-piston Stirling engine design. Overall (engine plus linear alternator) thermodynamic performance greater than 50% of Carnot, with a specific power close to 100 W/kg appears to be a reasonable goal at this small power level. Supporting test data and analysis results from exiting engines are presented. Design implications of high specific power in relatively low power engines is presented and discussed.

Skylab program earth resouces experiment package. Volume 4: Sensor performance evaluation (S193 R/S). [radiometer/scatterometer

NASA Technical Reports Server (NTRS)

Kenney, G. P.

1975-01-01

The results of the sensor performance evaluation of the 13.9 GHz radiometer/scatterometer, which was part of the earth resources experiment package on Skylab. Findings are presented in the areas of housekeeping parameters, antenna gain and scanning performance, dynamic range, linearity, precision, resolution, stability, integration time, and transmitter output. Supplementary analyses covering performance anomalies, data stream peculiarities, aircraft sensor data comparisons, scatterometer saturation characteristics, and RF heating effects are reported. Results of the evaluation show that instrument performance was generally as expected, but capability degradations were observed to result from three major anomalies. Conclusions are drawn from the evaluation results, and recommendations for improving the effectiveness of a future program are offered. An addendum describes the special evaluation techniques developed and applied in the sensor performance evaluation tasks.

Personality and job performance: the Big Five revisited.

PubMed

Hurtz, G M; Donovan, J J

2000-12-01

Prior meta-analyses investigating the relation between the Big 5 personality dimensions and job performance have all contained a threat to construct validity, in that much of the data included within these analyses was not derived from actual Big 5 measures. In addition, these reviews did not address the relations between the Big 5 and contextual performance. Therefore, the present study sought to provide a meta-analytic estimate of the criterion-related validity of explicit Big 5 measures for predicting job performance and contextual performance. The results for job performance closely paralleled 2 of the previous meta-analyses, whereas analyses with contextual performance showed more complex relations among the Big 5 and performance. A more critical interpretation of the Big 5-performance relationship is presented, and suggestions for future research aimed at enhancing the validity of personality predictors are provided.

The effects of gluteus maximus and abductor hallucis strengthening exercises for four weeks on navicular drop and lower extremity muscle activity during gait with flatfoot.

PubMed

Goo, Young-Mi; Kim, Tae-Ho; Lim, Jin-Yong

2016-03-01

[Purpose] The purpose of the present study is to examine the effects of abductor hallucis and gluteus maximus strengthening exercises on pronated feet. [Subjects and Methods] The present study was conducted with 18 adults without no history of surgery on the foot or ankle. One group performed both gluteus maximus strengthening exercises and abductor hallucis strengthening exercises, while the other group performed only abductor hallucis strengthening exercises five times per week for four weeks. [Results] The group that performed both gluteus maximus and abductor hallucis strengthening exercises showed smaller values in the height of navicular drop than the group that performed only abductor hallucis strengthening exercises. The muscle activity of the gluteus maximus and the vastus medialis increased during heel-strike in the group that added gluteus maximus exercises, and the muscle activity of the abductor hallucis significantly increased in both groups. [Conclusion] Given the results of the present study, it can be suggested that strengthening the gluteus maximus while also performing exercises to correct the pronated foot is an effective method for achieving normal gait.

Improved charging performance of Li-O2 batteries by forming Ba-incorporated Li2O2 as the discharge product

NASA Astrophysics Data System (ADS)

Matsuda, Shoichi; Uosaki, Kohei; Nakanishi, Shuji

2017-06-01

Although Li-O2 batteries can potentially achieve greater than two-fold higher energy densities than Li-ion batteries, the basic performance of Li-O2 batteries remains poor. In particular, the large over-potential of positive electrode reactions during the charging process results in low round-trip energy efficiency and limited cycle life, and is therefore the main barrier to the practical use of rechargeable Li-O2 batteries. In the present study, we demonstrate that the charging performance of Li-O2 batteries can be significantly improved by simply adding barium (Ba) ions into the electrolyte. Elemental analysis revealed that Ba-incorporated Li2O2 was obtained as the main discharge product of a Li-O2 cell operated in the presence of Ba2+. Notably, the improvement of charging performance was confirmed to originate from the Ba-incorporated Li2O2 deposits, rather than the Ba2+ present in the electrolyte. The present results suggest that the incorporation of heteroatoms into the discharge product is an effective approach for improving the charging performance of Li-O2 batteries.

Faying Surface Lubrication Effects on Nut Factors

NASA Technical Reports Server (NTRS)

Taylor, Deneen M.; Morrison, Raymond F.

2006-01-01

Bolted joint analysis typically is performed using nut factors derived from textbooks and procedures from program requirement documents. Joint specific testing was performed for a critical International Space Station (ISS) joint. Test results indicate that for some configurations the nut factor may be significantly different than accepted textbook values. This paper presents results of joint specific testing to aid in determining if joint specific testing should be performed to insure required preloads are obtained.

Standardization and validation of the body weight adjustment regression equations in Olympic weightlifting.

PubMed

Kauhanen, Heikki; Komi, Paavo V; Häkkinen, Keijo

2002-02-01

The problems in comparing the performances of Olympic weightlifters arise from the fact that the relationship between body weight and weightlifting results is not linear. In the present study, this relationship was examined by using a nonparametric curve fitting technique of robust locally weighted regression (LOWESS) on relatively large data sets of the weightlifting results made in top international competitions. Power function formulas were derived from the fitted LOWESS values to represent the relationship between the 2 variables in a way that directly compares the snatch, clean-and-jerk, and total weightlifting results of a given athlete with those of the world-class weightlifters (golden standards). A residual analysis of several other parametric models derived from the initial results showed that they all experience inconsistencies, yielding either underestimation or overestimation of certain body weights. In addition, the existing handicapping formulas commonly used in normalizing the performances of Olympic weightlifters did not yield satisfactory results when applied to the present data. It was concluded that the devised formulas may provide objective means for the evaluation of the performances of male weightlifters, regardless of their body weights, ages, or performance levels.

Hardware test program for evaluation of baseline range/range rate sensor concept

NASA Technical Reports Server (NTRS)

Pernic, E.

1985-01-01

The test program Phase II effort provides additional design information in terms of range and range rate (R/R) sensor performance when observing and tracking a typical spacecraft target. The target used in the test program was a one-third scale model of the Hubble Space Telescope (HST) available at the MSFC test site where the tests were performed. A modified Bendix millimeter wave radar served as the R/R sensor test bed for evaluation of range and range rate tracking performance, and generation of radar signature characteristics of the spacecraft target. A summary of program test results and conclusions are presented along with detailed description of the Bendix test bed radar with accompaning instrumentation. The MSFC test site and facilities are described. The test procedures used to establish background levels, and the calibration procedures used in the range accuracy tests and RCS (radar cross section) signature measurements, are presented and a condensed version of the daily log kept during the 5 September through 17 September test period is also presented. The test program results are given starting with the RCS signature measurements, then continuing with range measurement accuracy test results and finally the range and range rate tracking accuracy test results.

D-region blunt probe data analysis using hybrid computer techniques

NASA Technical Reports Server (NTRS)

Burkhard, W. J.

1973-01-01

The feasibility of performing data reduction techniques with a hybrid computer was studied. The data was obtained from the flight of a parachute born probe through the D-region of the ionosphere. A presentation of the theory of blunt probe operation is included with emphasis on the equations necessary to perform the analysis. This is followed by a discussion of computer program development. Included in this discussion is a comparison of computer and hand reduction results for the blunt probe launched on 31 January 1972. The comparison showed that it was both feasible and desirable to use the computer for data reduction. The results of computer data reduction performed on flight data acquired from five blunt probes are also presented.

Flight test report of the NASA icing research airplane: Performance, stability, and control after flight through natural icing conditions

NASA Technical Reports Server (NTRS)

Jordan, J. L.; Platz, S. J.; Schinstock, W. C.

1986-01-01

Flight test results are presented documenting the effect of airframe icing on performance and stability and control of a NASA DHC-6 icing research aircraft. Kohlman System Research, Inc., provided the data acquisition system and data analysis under contract to NASA. Performance modeling methods and MMLE techniques were used to determine the effects of natural ice on the aircraft. Results showed that ice had a significant effect on the drag coefficient of the aircraft and a modest effect on the MMLE derived longitudinal stability coefficients (code version MMLE). Data is also presented on asymmetric power sign slip maneuvers showing rudder floating characteristics with and without ice on the vertical stabilizer.

Implementation of probe data performance measures.

DOT National Transportation Integrated Search

2017-04-03

This report presents results from a 12-month project where three arterial analysis tools based on probe vehicle segment speed data were developed for District 6. A case study of 5 arterials and two incidents was performed.

HEAT TRANSFER EVALUATION OF HFC-236EA WITH HIGH PERFORMANCE ENHANCED TUBES IN CONDENSATION AND EVAPORATION

EPA Science Inventory

The report gives results of an evaluation of the heat transfer performance of pure hydrofluorocarbon (HFC)-236ea for high performance enhanced tubes which had not been previously used in Navy shipboard chillers. Shell-side heat transfer coefficient data are presented for condensa...

PERFORMANCE OF TWO LIQUID METAL TURBOPROP ENGINES UTILIZING A CIRCULATING FUEL REACTOR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tiedemann, H.J.; Mathews, L.

1955-01-20

The performance of two all-nuclear turboprop engines utilizing the circulating fuel reactor with a fluoride fuel temperature of I500 deg F was investigated. Data are presented for off-match-point and modified match-point performances. Results are given in graph form. (M.C.G.)

Conflict Detection Performance Analysis for Function Allocation Using Time-Shifted Recorded Traffic Data

NASA Technical Reports Server (NTRS)

Guerreiro, Nelson M.; Butler, Ricky W.; Maddalon, Jeffrey M.; Hagen, George E.; Lewis, Timothy A.

2015-01-01

The performance of the conflict detection function in a separation assurance system is dependent on the content and quality of the data available to perform that function. Specifically, data quality and data content available to the conflict detection function have a direct impact on the accuracy of the prediction of an aircraft's future state or trajectory, which, in turn, impacts the ability to successfully anticipate potential losses of separation (detect future conflicts). Consequently, other separation assurance functions that rely on the conflict detection function - namely, conflict resolution - are prone to negative performance impacts. The many possible allocations and implementations of the conflict detection function between centralized and distributed systems drive the need to understand the key relationships that impact conflict detection performance, with respect to differences in data available. This paper presents the preliminary results of an analysis technique developed to investigate the impacts of data quality and data content on conflict detection performance. Flight track data recorded from a day of the National Airspace System is time-shifted to create conflicts not present in the un-shifted data. A methodology is used to smooth and filter the recorded data to eliminate sensor fusion noise, data drop-outs and other anomalies in the data. The metrics used to characterize conflict detection performance are presented and a set of preliminary results is discussed.

A Data Encryption Solution for Mobile Health Apps in Cooperation Environments

PubMed Central

Silva, Bruno M; Canelo, Fábio; Lopes, Ivo C; Zhou, Liang

2013-01-01

Background Mobile Health (mHealth) proposes health care delivering anytime and anywhere. It aims to answer several emerging problems in health services, including the increasing number of chronic diseases, high costs on national health services, and the need to provide direct access to health services, regardless of time and place. mHealth systems include the use of mobile devices and apps that interact with patients and caretakers. However, mobile devices present several constraints, such as processor, energy, and storage resource limitations. The constant mobility and often-required Internet connectivity also exposes and compromises the privacy and confidentiality of health information. Objective This paper presents a proposal, construction, performance evaluation, and validation of a data encryption solution for mobile health apps (DE4MHA), considering a novel and early-proposed cooperation strategy. The goal was to present a robust solution based on encryption algorithms that guarantee the best confidentiality, integrity, and authenticity of users health information. In this paper, we presented, explained, evaluated the performance, and discussed the cooperation mechanisms and the proposed encryption solution for mHealth apps. Methods First, we designed and deployed the DE4MHA. Then two studies were performed: (1) study and comparison of symmetric and asymmetric encryption/decryption algorithms in an mHealth app under a cooperation environment, and (2) performance evaluation of the DE4MHA. Its performance was evaluated through a prototype using an mHealth app for obesity prevention and cares, called SapoFit. We then conducted an evaluation study of the mHealth app with cooperation mechanisms and the DE4MHA using real users and a real cooperation scenario. In 5 days, 5 different groups of 7 students selected randomly agreed to use and experiment the SapoFit app using the 7 devices available for trials. Results There were 35 users of SapoFit that participated in this study. The performance evaluation of the app was done using 7 real mobile devices in 5 different days. The results showed that confidentiality and protection of the users’ health information was guaranteed and SapoFit users were able to use the mHealth app with satisfactory quality. Results also showed that the app with the DE4MHA presented nearly the same results as the app without the DE4MHA. The performance evaluation results considered the probability that a request was successfully answered as a function of the number of uncooperative nodes in the network. The service delivery probability decreased with the increase of uncooperative mobile nodes. Using DE4MHA, it was observed that performance presented a slightly worse result. The service average was also slightly worse but practically insignificantly different than with DE4MHA, being considered negligible. Conclusions This paper proposed a data encryption solution for mobile health apps, called DE4MHA. The data encryption algorithm DE4MHA with cooperation mechanisms in mobile health allow users to safely obtain health information with the data being carried securely. These security mechanisms did not deteriorate the overall network performance and the app, maintaining similar performance levels as without the encryption. More importantly, it offers a robust and reliable increase of privacy, confidentiality, integrity, and authenticity of their health information. Although it was experimented on a specific mHealth app, SapoFit, both DE4MHA and the cooperation strategy can be deployed in other mHealth apps. PMID:23624056

Software Engineering Laboratory (SEL) Ada performance study report

NASA Technical Reports Server (NTRS)

Booth, Eric W.; Stark, Michael E.

1991-01-01

The goals of the Ada Performance Study are described. The methods used are explained. Guidelines for future Ada development efforts are given. The goals and scope of the study are detailed, and the background of Ada development in the Flight Dynamics Division (FDD) is presented. The organization and overall purpose of each test are discussed. The purpose, methods, and results of each test and analyses of these results are given. Guidelines for future development efforts based on the analysis of results from this study are provided. The approach used on the performance tests is discussed.

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

Exploring rationality in schizophrenia

PubMed Central

Mortensen, Erik Lykke; Owen, Gareth; Nordgaard, Julie; Jansson, Lennart; Sæbye, Ditte; Flensborg-Madsen, Trine; Parnas, Josef

2015-01-01

Background Empirical studies of rationality (syllogisms) in patients with schizophrenia have obtained different results. One study found that patients reason more logically if the syllogism is presented through an unusual content. Aims To explore syllogism-based rationality in schizophrenia. Method Thirty-eight first-admitted patients with schizophrenia and 38 healthy controls solved 29 syllogisms that varied in presentation content (ordinary v. unusual) and validity (valid v. invalid). Statistical tests were made of unadjusted and adjusted group differences in models adjusting for intelligence and neuropsychological test performance. Results Controls outperformed patients on all syllogism types, but the difference between the two groups was only significant for valid syllogisms presented with unusual content. However, when adjusting for intelligence and neuropsychological test performance, all group differences became non-significant. Conclusions When taking intelligence and neuropsychological performance into account, patients with schizophrenia and controls perform similarly on syllogism tests of rationality. Declaration of interest None. Copyright and usage © The Royal College of Psychiatrists 2015. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence. PMID:27703730

Extra-Vehicular Activity (EVA) glove evaluation test protocol

NASA Technical Reports Server (NTRS)

Hinman-Sweeney, E. M.

1994-01-01

One of the most critical components of a space suit is the gloves, yet gloves have traditionally presented significant design challenges. With continued efforts at glove development, a method for evaluating glove performance is needed. This paper presents a pressure-glove evaluation protocol. A description of this evaluation protocol, and its development is provided. The protocol allows comparison of one glove design to another, or any one design to bare-handed performance. Gloves for higher pressure suits may be evaluated at current and future design pressures to drive out differences in performance due to pressure effects. Using this protocol, gloves may be evaluated during design to drive out design problems and determine areas for improvement, or fully mature designs may be evaluated with respect to mission requirements. Several different test configurations are presented to handle these cases. This protocol was run on a prototype glove. The prototype was evaluated at two operating pressures and in the unpressurized state, with results compared to bare-handed performance. Results and analysis from this test series are provided, as is a description of the configuration used for this test.

Performance Test Data Analysis of Scintillation Cameras

NASA Astrophysics Data System (ADS)

Demirkaya, Omer; Mazrou, Refaat Al

2007-10-01

In this paper, we present a set of image analysis tools to calculate the performance parameters of gamma camera systems from test data acquired according to the National Electrical Manufacturers Association NU 1-2001 guidelines. The calculation methods are either completely automated or require minimal user interaction; minimizing potential human errors. The developed methods are robust with respect to varying conditions under which these tests may be performed. The core algorithms have been validated for accuracy. They have been extensively tested on images acquired by the gamma cameras from different vendors. All the algorithms are incorporated into a graphical user interface that provides a convenient way to process the data and report the results. The entire application has been developed in MATLAB programming environment and is compiled to run as a stand-alone program. The developed image analysis tools provide an automated, convenient and accurate means to calculate the performance parameters of gamma cameras and SPECT systems. The developed application is available upon request for personal or non-commercial uses. The results of this study have been partially presented in Society of Nuclear Medicine Annual meeting as an InfoSNM presentation.

Longitudinal performance of infants with cerebral palsy on the Test of Infant Motor Performance and on the Alberta Infant Motor Scale.

PubMed

Barbosa, Vanessa M; Campbell, Suzann K; Sheftel, David; Singh, Jaidep; Beligere, Nagamani

2003-01-01

Understanding the natural history of development in children with cerebral palsy (CP) is important for studying the consequences of early intervention. The purpose of this paper is to present results on the Test of Infant Motor Performance (TIMP) from 0-4 months of age and on the Alberta Infant Motor Scale (AIMS) from 3 to 12 months of age in a group of infants later diagnosed as having CP. Ages at which infants with CP were first recognized as having delayed motor performance on each instrument and the stability of performance over time are presented. Clinical implications for using both instruments are discussed.

Performance optimization of an MHD generator with physical constraints

NASA Technical Reports Server (NTRS)

Pian, C. C. P.; Seikel, G. R.; Smith, J. M.

1979-01-01

A technique has been described which optimizes the power out of a Faraday MHD generator operating under a prescribed set of electrical and magnetic constraints. The method does not rely on complicated numerical optimization techniques. Instead the magnetic field and the electrical loading are adjusted at each streamwise location such that the resultant generator design operates at the most limiting of the cited stress levels. The simplicity of the procedure makes it ideal for optimizing generator designs for system analysis studies of power plants. The resultant locally optimum channel designs are, however, not necessarily the global optimum designs. The results of generator performance calculations are presented for an approximately 2000 MWe size plant. The difference between the maximum power generator design and the optimal design which maximizes net MHD power are described. The sensitivity of the generator performance to the various operational parameters are also presented.

Sunlight-readable display technology: a dual-use case study

NASA Astrophysics Data System (ADS)

Blanchard, Randall D.

1996-05-01

This paper describes our vision of sunlight readable color display requirements, an alternate technology that offers a high level of performance, and how we implemented it for the military avionics display market. This knowledge base and product development experience was then applied with a comparable level of performance to commercial applications. The successful dual use of this technology for these two diverse markets is presented. Details of the technical commonality and a comparison of the design and performance differences are presented. A basis for specifying the required level of performance for a sunlight readable full color display is discussed. With the objective of providing a high level of image brightness and high ambient light rejection, a display architecture using collimated light is used. The resulting designs of two military cockpit display products, with contrast ratios above 20:1 in sunlight are shown. The performance of a commercial display providing several thousand foot- Lamberts of image brightness is presented.

Hybrid TE panel test results

NASA Technical Reports Server (NTRS)

Bifano, W. J.

1972-01-01

Test results are presented for a nine couple (3 x 3 array) thermoelectric panel of hybrid thermocouples. In the hybrid couple, a hollow cylinder of p-type Si-Ge is used to encapsulate a segmented PbTe/Si-Ge n-leg. The hybrid couple is predicted to offer a 10- to 15-percent improvement in performance relative to all Si-Ge couples. The efficiency, output power, and internal resistance of the panel as well as the resistances of the individual hybrid couples are presented as a function of test time covering a period of more than 2600 hours. Initial test results indicated hybrid couple performance consistent with design predictions. Extraneous resistance ranged from 20 to 25% of the hybrid couple thermoelectric resistance.

NAS Parallel Benchmark Results 11-96. 1.0

NASA Technical Reports Server (NTRS)

Bailey, David H.; Bailey, David; Chancellor, Marisa K. (Technical Monitor)

1997-01-01

The NAS Parallel Benchmarks have been developed at NASA Ames Research Center to study the performance of parallel supercomputers. The eight benchmark problems are specified in a "pencil and paper" fashion. In other words, the complete details of the problem to be solved are given in a technical document, and except for a few restrictions, benchmarkers are free to select the language constructs and implementation techniques best suited for a particular system. These results represent the best results that have been reported to us by the vendors for the specific 3 systems listed. In this report, we present new NPB (Version 1.0) performance results for the following systems: DEC Alpha Server 8400 5/440, Fujitsu VPP Series (VX, VPP300, and VPP700), HP/Convex Exemplar SPP2000, IBM RS/6000 SP P2SC node (120 MHz), NEC SX-4/32, SGI/CRAY T3E, SGI Origin200, and SGI Origin2000. We also report High Performance Fortran (HPF) based NPB results for IBM SP2 Wide Nodes, HP/Convex Exemplar SPP2000, and SGI/CRAY T3D. These results have been submitted by Applied Parallel Research (APR) and Portland Group Inc. (PGI). We also present sustained performance per dollar for Class B LU, SP and BT benchmarks.

Inter-individual differences in how presentation modality affects verbal learning performance in children aged 5 to 16.

PubMed

Meijs, Celeste; Hurks, Petra P M; Wassenberg, Renske; Feron, Frans J M; Jolles, Jelle

2016-01-01

This study examines inter-individual differences in how presentation modality affects verbal learning performance. Children aged 5 to 16 performed a verbal learning test within one of three presentation modalities: pictorial, auditory, or textual. The results indicated that a beneficial effect of pictures exists over auditory and textual presentation modalities and that this effect increases with age. However, this effect is only found if the information to be learned is presented once (or at most twice) and only in children above the age of 7. The results may be explained in terms of single or dual coding of information in which the phonological loop is involved. Development of the (sub)vocal rehearsal system in the phonological loop is believed to be a gradual process that begins developing around the age of 7. The developmental trajectories are similar for boys and girls. Additionally, auditory information and textual information both seemed to be processed in a similar manner, namely without labeling or recoding, leading to single coding. In contrast, pictures are assumed to be processed by the dual coding of both the visual information and a (verbal) labeling of the pictures.

Marijuana and actual driving performance

DOT National Transportation Integrated Search

1993-11-01

This report concerns the effects of marijuana smoking on actual driving performance. It presents the results of one pilot and three actual driving studies. The pilot study's major purpose was to establish the THC dose current marijuana users smoke to...

LWIR Snapshot Imaging Polarimeter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dr. Robert E Sampson

This report describes the results of a phase 1 STTR to design a longwave infrared imaging polarimeter. The system design, expected performance and components needed to construct the imaging polarimeter are described. Expected performance is modeled and sytem specifications are presented.

Optimizing construction quality management of pavements using mechanistic performance analysis.

DOT National Transportation Integrated Search

2004-08-01

This report presents a statistical-based algorithm that was developed to reconcile the results from several pavement performance models used in the state of practice with systematic process control techniques. These algorithms identify project-specif...

Different Approaches for Ensuring Performance/Reliability of Plastic Encapsulated Microcircuits (PEMs) in Space Applications

NASA Technical Reports Server (NTRS)

Gerke, R. David; Sandor, Mike; Agarwal, Shri; Moor, Andrew F.; Cooper, Kim A.

1999-01-01

This paper presents viewgraphs on Plastic Encapsulated Microcircuits (PEMs). Different approaches are addressed to ensure good performance and reliability of PEMs. The topics include: 1) Mitigating Risk; and 2) Program results.

A comparison of transient vehicle performance using a fixed geometry, wastegated turbocharger and a variable geometry turbocharger

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lundstrom, R.R.; Gall, J.M.

1986-01-01

The use of an exhaust-driven boosting device can significantly improve the performance of a vehicle using a small displacement engine. One of the concerns relative to the performance of vehicles using these devices is ''turbo lag,'' or the period of time during which no boost is generated. This paper presents the results of designed experiments comparing the performance of a fixed geometry, wastegated turbocharger to a variable geometry turbocharger incorporating a low-loss bearing system. In addition, experimental tests are presented for the naturally aspirated engine in the same vehicle. The results of the experiments show improvements with the use ofmore » pressure boosting and that there are signifcant differences in the boosting devices tested; specifically, the use of a variable geometry turbocharger demonstrates significant reduction in the length of time required to reach boost and reduced acceleration times for the tests conducted.« less

Performance of highly connected photonic switching lossless metro-access optical networks

NASA Astrophysics Data System (ADS)

Martins, Indayara Bertoldi; Martins, Yara; Barbosa, Felipe Rudge

2018-03-01

The present work analyzes the performance of photonic switching networks, optical packet switching (OPS) and optical burst switching (OBS), in mesh topology of different sizes and configurations. The "lossless" photonic switching node is based on a semiconductor optical amplifier, demonstrated and validated with experimental results on optical power gain, noise figure, and spectral range. The network performance was evaluated through computer simulations based on parameters such as average number of hops, optical packet loss fraction, and optical transport delay (Am). The combination of these elements leads to a consistent account of performance, in terms of network traffic and packet delivery for OPS and OBS metropolitan networks. Results show that a combination of highly connected mesh topologies having an ingress e-buffer present high efficiency and throughput, with very low packet loss and low latency, ensuring fast data delivery to the final receiver.

Run-time parallelization and scheduling of loops

NASA Technical Reports Server (NTRS)

Saltz, Joel H.; Mirchandaney, Ravi; Crowley, Kay

1990-01-01

Run time methods are studied to automatically parallelize and schedule iterations of a do loop in certain cases, where compile-time information is inadequate. The methods presented involve execution time preprocessing of the loop. At compile-time, these methods set up the framework for performing a loop dependency analysis. At run time, wave fronts of concurrently executable loop iterations are identified. Using this wavefront information, loop iterations are reordered for increased parallelism. Symbolic transformation rules are used to produce: inspector procedures that perform execution time preprocessing and executors or transformed versions of source code loop structures. These transformed loop structures carry out the calculations planned in the inspector procedures. Performance results are presented from experiments conducted on the Encore Multimax. These results illustrate that run time reordering of loop indices can have a significant impact on performance. Furthermore, the overheads associated with this type of reordering are amortized when the loop is executed several times with the same dependency structure.

Measured effects of coolant injection on the performance of a film cooled turbine

NASA Technical Reports Server (NTRS)

Mcdonel, J. D.; Eiswerth, J. E.

1977-01-01

Tests have been conducted on a 20-inch diameter single-stage air-cooled turbine designed to evaluate the effects of film cooling air on turbine aerodynamic performance. The present paper reports the results of five test configurations, including two different cooling designs and three combinations of cooled and solid airfoils. A comparison is made of the experimental results with a previously published analytical method of evaluating coolant injection effects on turbine performance.

Sensing Methods for Detecting Analog Television Signals

NASA Astrophysics Data System (ADS)

Rahman, Mohammad Azizur; Song, Chunyi; Harada, Hiroshi

This paper introduces a unified method of spectrum sensing for all existing analog television (TV) signals including NTSC, PAL and SECAM. We propose a correlation based method (CBM) with a single reference signal for sensing any analog TV signals. In addition we also propose an improved energy detection method. The CBM approach has been implemented in a hardware prototype specially designed for participating in Singapore TV white space (WS) test trial conducted by Infocomm Development Authority (IDA) of the Singapore government. Analytical and simulation results of the CBM method will be presented in the paper, as well as hardware testing results for sensing various analog TV signals. Both AWGN and fading channels will be considered. It is shown that the theoretical results closely match with those from simulations. Sensing performance of the hardware prototype will also be presented in fading environment by using a fading simulator. We present performance of the proposed techniques in terms of probability of false alarm, probability of detection, sensing time etc. We also present a comparative study of the various techniques.

Ambient Information Systems to Support the Elderly in Carrying Out Their Activities of Daily Living

NASA Astrophysics Data System (ADS)

García-Vázquez, Juan Pablo; Rodríguez, Marcela D.

As they age, older adult's present losses in their functional capabilities which cause them can't continue performing their activities of daily living (ADL) independently at home. We propose Ambient Information Systems (AIS) as appropriate pervasive devices to promote their independent living. Therefore our aim is to determine the utility and usability of AIS to support the independent life of older adults by helping them to perform their activities. In this paper we present preliminary results of a case study that we carried out for understanding the problems and needs that older adults face in doing some of their activities of daily living. In particular, we present results regarding the elderly problems to adhere to their medication prescription. Based on these results we propose AIS to support older adults to medicate. Finally, we present the design attributes incorporated into this AIS, which were identified from the design taxonomies of AIS reported in the literature.

An Overview of the Semi-Span Super-Sonic Transport (S4T) Wind-Tunnel Model Program

NASA Technical Reports Server (NTRS)

Silva, Walter A.; Perry, Boyd, III; Florance, James R.; Sanetrik, Mark D.; Wieseman, Carol D.; Stevens, William L.; Funk, Christie J.; Christhilf, David M.; Coulson, David A.

2012-01-01

A summary of computational and experimental aeroelastic (AE) and aeroservoelastic (ASE) results for the Semi-Span Super-Sonic Transport (S4T) wind-tunnel model is presented. A broad range of analyses and multiple AE and ASE wind-tunnel tests of the S4T wind-tunnel model have been performed in support of the ASE element in the Supersonics Program, part of the NASA Fundamental Aeronautics Program. This paper is intended to be an overview of multiple papers that comprise a special S4T technical session. Along those lines, a brief description of the design and hardware of the S4T wind-tunnel model will be presented. Computational results presented include linear and nonlinear aeroelastic analyses, and rapid aeroelastic analyses using CFD-based reduced-order models (ROMs). A brief survey of some of the experimental results from two open-loop and two closed-loop wind-tunnel tests performed at the NASA Langley Transonic Dynamics Tunnel (TDT) will be presented as well.

Do Diligent Students Perform Better? Complex Relations between Student and Course Characteristics, Study Time, and Academic Performance in Higher Education

ERIC Educational Resources Information Center

Masui, Chris; Broeckmans, Jan; Doumen, Sarah; Groenen, Anne; Molenberghs, Geert

2014-01-01

Research has reported equivocal results regarding the relationship between study time investment and academic performance in higher education. In the setting of the active, assignment-based teaching approach at Hasselt University (Belgium), the present study aimed (a) to further clarify the role of study time in academic performance, while taking…

Development of a 30-cm ion thruster thermal-vacuum power processor

NASA Technical Reports Server (NTRS)

Herron, B. G.

1976-01-01

The 30-cm Hg electron-bombardment ion thruster presently under development has reached engineering model status and is generally accepted as the prime propulsion thruster module to be used on the earliest solar electric propulsion missions. This paper presents the results of a related program to develop a transistorized 3-kW Thermal-Vacuum Breadboard (TVBB) Power Processor for this thruster. Emphasized in the paper are the implemented electrical and mechanical designs as well as the resultant system performance achieved over a range of test conditions. In addition, design modifications affording improved performance are identified and discussed.

Benchmark experiments at ASTRA facility on definition of space distribution of {sup 235}U fission reaction rate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bobrov, A. A.; Boyarinov, V. F.; Glushkov, A. E.

2012-07-01

Results of critical experiments performed at five ASTRA facility configurations modeling the high-temperature helium-cooled graphite-moderated reactors are presented. Results of experiments on definition of space distribution of {sup 235}U fission reaction rate performed at four from these five configurations are presented more detail. Analysis of available information showed that all experiments on criticality at these five configurations are acceptable for use them as critical benchmark experiments. All experiments on definition of space distribution of {sup 235}U fission reaction rate are acceptable for use them as physical benchmark experiments. (authors)

Design and performance of an analysis-by-synthesis class of predictive speech coders

NASA Technical Reports Server (NTRS)

Rose, Richard C.; Barnwell, Thomas P., III

1990-01-01

The performance of a broad class of analysis-by-synthesis linear predictive speech coders is quantified experimentally. The class of coders includes a number of well-known techniques as well as a very large number of speech coders which have not been named or studied. A general formulation for deriving the parametric representation used in all of the coders in the class is presented. A new coder, named the self-excited vocoder, is discussed because of its good performance with low complexity, and because of the insight this coder gives to analysis-by-synthesis coders in general. The results of a study comparing the performances of different members of this class are presented. The study takes the form of a series of formal subjective and objective speech quality tests performed on selected coders. The results of this study lead to some interesting and important observations concerning the controlling parameters for analysis-by-synthesis speech coders.

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.

Using the surface panel method to predict the steady performance of ducted propellers

NASA Astrophysics Data System (ADS)

Cai, Hao-Peng; Su, Yu-Min; Li, Xin; Shen, Hai-Long

2009-12-01

A new numerical method was developed for predicting the steady hydrodynamic performance of ducted propellers. A potential based surface panel method was applied both to the duct and the propeller, and the interaction between them was solved by an induced velocity potential iterative method. Compared with the induced velocity iterative method, the method presented can save programming and calculating time. Numerical results for a JD simplified ducted propeller series showed that the method presented is effective for predicting the steady hydrodynamic performance of ducted propellers.

Numerical flow analysis of axial flow compressor for steady and unsteady flow cases

NASA Astrophysics Data System (ADS)

Prabhudev, B. M.; Satish kumar, S.; Rajanna, D.

2017-07-01

Performance of jet engine is dependent on the performance of compressor. This paper gives numerical study of performance characteristics for axial compressor. The test rig is present at CSIR LAB Bangalore. Flow domains are meshed and fluid dynamic equations are solved using ANSYS package. Analysis is done for six different speeds and for operating conditions like choke, maximum efficiency & before stall point. Different plots are compared and results are discussed. Shock displacement, vortex flows, leakage patterns are presented along with unsteady FFT plot and time step plot.

Ten-kilogram vehicle autonomous operations

NASA Astrophysics Data System (ADS)

Rogers, John R.; Korpela, Christopher; Quigley, Kevin

2009-05-01

A low-cost unmanned ground vehicle designed to benchmark high-speed performance is presented. The E-Maxx four-wheel-drive radio-controlled vehicle equipped with a Robostix controller is proposed as a low-cost, high-speed robotic platform useful for military operations. The vehicle weighs less than ten kilograms making it easily portable by one person. Keeping cost low is a major consideration in the design with the aim of providing a disposable military robot. The suitability of the platform was evaluated and results are presented. Commercial-Off-The-Shelf (COTS) upgrades to the basic vehicle are recommended for durability. A procedure was established for bird's-eye-view video recording to document vehicle dynamics. Driver/vehicle performance is quantified by entry velocity, exit velocity and total time through a 90° turn on low-friction terrain. A setup for measuring these values is presented. Expert drivers use controlled skidding to minimize time through turns and the long term goal of the project is to automate such expert behaviors. Results of vehicle performance under human control are presented and stand as a reference for future autonomy.

Comparison of Analytical Predictions and Experimental Results for a Dual Brayton Power System (Discussion on Test Hardware and Computer Model for a Dual Brayton System)

NASA Technical Reports Server (NTRS)

Johnson, Paul K.

2007-01-01

NASA Glenn Research Center (GRC) contracted Barber-Nichols, Arvada, CO to construct a dual Brayton power conversion system for use as a hardware proof of concept and to validate results from a computational code known as the Closed Cycle System Simulation (CCSS). Initial checkout tests were performed at Barber- Nichols to ready the system for delivery to GRC. This presentation describes the system hardware components and lists the types of checkout tests performed along with a couple issues encountered while conducting the tests. A description of the CCSS model is also presented. The checkout tests did not focus on generating data, therefore, no test data or model analyses are presented.

On the Performance Evaluation of 3D Reconstruction Techniques from a Sequence of Images

NASA Astrophysics Data System (ADS)

Eid, Ahmed; Farag, Aly

2005-12-01

The performance evaluation of 3D reconstruction techniques is not a simple problem to solve. This is not only due to the increased dimensionality of the problem but also due to the lack of standardized and widely accepted testing methodologies. This paper presents a unified framework for the performance evaluation of different 3D reconstruction techniques. This framework includes a general problem formalization, different measuring criteria, and a classification method as a first step in standardizing the evaluation process. Performance characterization of two standard 3D reconstruction techniques, stereo and space carving, is also presented. The evaluation is performed on the same data set using an image reprojection testing methodology to reduce the dimensionality of the evaluation domain. Also, different measuring strategies are presented and applied to the stereo and space carving techniques. These measuring strategies have shown consistent results in quantifying the performance of these techniques. Additional experiments are performed on the space carving technique to study the effect of the number of input images and the camera pose on its performance.

First results from experiments performed with the ESA Anthrorack during the D-2 Spacelab mission.

PubMed

Kuipers, A

1996-06-01

In 1993 four astronauts performed physiological experiments on the payload "Anthrorack" during the second German Spacelab mission D-2. The Anthrorack set-up is a Spacelab double rack developed under the management of the European Space Agency. It consists of an ECHO machine, a respiratory monitoring system (gas analyzer with flow meter), a blood centrifuge, an ergometer, a finger blood pressure device, ECG, body impedance measurement device and a respiratory inductance plethysmograph. Experiment-specific equipment was used as well. Nineteen investigators performed experiments in the cardiovascular, pulmonary, fluid-renal and nutritional physiology area. Results on central venous pressure, ocular pressure, vascular resistance, cardiac output, tissue thickness and orthostatic intolerance are presented in the cardiovascular area. In the pulmonary area first results are mentioned on O2 transport perfusion and ventilation distribution and breathing pattern. From the fluid-renal experiments, data from diuresis, sodium excretion and hormonal determinations are given. Finally results from glucose metabolism and nitrogen turnover experiments are presented.

First results from experiments performed with the ESA Anthrorack during the D-2 spacelab mission

NASA Astrophysics Data System (ADS)

Kuipers, A.

1996-06-01

In 1993 four astronauts performed physiological experiments on the payload "Anthrorack" during the second German Spacelab mission D-2. The Anthrorack set-up is a Spacelab double rack developed under the management of the European Space Agency. It consists of an ECHO machine, a respiratory monitoring system (gas analyzer with flow meter), a blood centrifuge, an ergometer, a finger blood pressure device, ECG, body impedance measurement device and a respiratory inductance plethysmograph. Experiment-specific equipment was used as well. Nineteen investigators performed experiments in the cardiovascular, pulmonary, fluid-renal and nutritional physiology area. Results on central venous pressure, ocular pressure, vascular resistance, cardiac output, tissue thickness and orthostatic intolerance are presented in the cardiovascular area. In the pulmonary area first results are mentioned on O 2 transport perfusion and ventilation distribution and breathing pattern. From the fluid-renal experiments, data from diuresis, sodium excretion and hormonal determinations are given. Finally results from glucose metabolism and nitrogen turnover experiments are presented.

Performance assessment of human resource by integration of HSE and ergonomics and EFQM management system.

PubMed

Sadegh Amalnick, Mohsen; Zarrin, Mansour

2017-03-13

Purpose The purpose of this paper is to present an integrated framework for performance evaluation and analysis of human resource (HR) with respect to the factors of health, safety, environment and ergonomics (HSEE) management system, and also the criteria of European federation for quality management (EFQM) as one of the well-known business excellence models. Design/methodology/approach In this study, an intelligent algorithm based on adaptive neuro-fuzzy inference system (ANFIS) along with fuzzy data envelopment analysis (FDEA) are developed and employed to assess the performance of the company. Furthermore, the impact of the factors on the company's performance as well as their strengths and weaknesses are identified by conducting a sensitivity analysis on the results. Similarly, a design of experiment is performed to prioritize the factors in the order of importance. Findings The results show that EFQM model has a far greater impact upon the company's performance than HSEE management system. According to the obtained results, it can be argued that integration of HSEE and EFQM leads to the performance improvement in the company. Practical implications In current study, the required data for executing the proposed framework are collected via valid questionnaires which are filled in by the staff of an aviation industry located in Tehran, Iran. Originality/value Managing HR performance results in improving usability, maintainability and reliability and finally in a significant reduction in the commercial aviation accident rate. Also, study of factors affecting HR performance authorities participate in developing systems in order to help operators better manage human error. This paper for the first time presents an intelligent framework based on ANFIS, FDEA and statistical tests for HR performance assessment and analysis with the ability of handling uncertainty and vagueness existing in real world environment.

Internal performance predictions for Langley scramjet engine module

NASA Technical Reports Server (NTRS)

Pinckney, S. Z.

1978-01-01

A one dimensional theoretical method for the prediction of the internal performance of a scramjet engine is presented. The effects of changes in vehicle forebody flow parameters and characteristics on predicted thrust for the scramjet engine were evaluated using this method, and results are presented. A theoretical evaluation of the effects of changes in the scramjet engine's internal parameters is also presented. Theoretical internal performance predictions, in terms thrust coefficient and specific impulse, are provided for the scramjet engine for free stream Mach numbers of 5, 6, and 7 free stream dynamic pressure of 23,940 N/sq m forebody surface angles of 4.6 deg to 14.6 deg, and fuel equivalence ratio of 1.0.

Photonic crystal fiber technology for compact fiber-delivered high-power ultrafast fiber lasers

NASA Astrophysics Data System (ADS)

Triches, Marco; Michieletto, Mattia; Johansen, Mette M.; Jakobsen, Christian; Olesen, Anders S.; Papior, Sidsel R.; Kristensen, Torben; Bondue, Magalie; Weirich, Johannes; Alkeskjold, Thomas T.

2018-02-01

Photonic crystal fiber (PCF) technology has radically impacted the scientific and industrial ultrafast laser market. Reducing platform dimensions are important to decrease cost and footprint while maintaining high optical efficiency. We present our recent work on short 85 μm core ROD-type fiber amplifiers that maintain single-mode performance and excellent beam quality. Robust long-term performance at 100 W average power and 250 kW peak power in 20 ps pulses at 1030 nm wavelength is presented, exceeding 500 h with stable performance in terms of both polarization and power. In addition, we present our recent results on hollow-core ultrafast fiber delivery maintaining high beam quality and polarization purity.

Static performance tests of a flight-type STOVL ejector

NASA Technical Reports Server (NTRS)

Barankiewicz, Wendy S.

1991-01-01

The design and development of thrust augmenting STOVL ejectors has typically been based on experimental iteration (i.e., trial and error). Static performance tests of a full scale vertical lift ejector were performed at primary flow temperatures up to 1560 R (1100 F). Flow visualization (smoke generators and yarn tufts) were used to view the inlet air flow, especially around the primary nozzle and end plates. Performance calculations are presented for ambient temperatures close to 480 R (20 F) and 535 R (75 F) which simulate seasonal aircraft operating conditions. Resulting thrust augmentation ratios are presented as functions of nozzle pressure ratio and temperature.

Effects of Organization and Instruction on Free and Cued Recall in Lower Socioeconomic Status Fourth Graders.

ERIC Educational Resources Information Center

Phye, Gary D.; Zimmerman, Bonnie B.

Free recall, cued recall, and clustering performance of fourth grade lower socioeconomic black and white children is studied under four conditions of teaching: random presentation, random presentation plus instruction, blocked presentation, and blocked presentation with instruction of categorically related list. Results indicate that both recall…

Adapting research-based curricula at Seattle Pacific University: Results on student learning

NASA Astrophysics Data System (ADS)

Close, Eleanor; Vokos, Stamatis; Lindberg, John; Seeley, Lane

2004-05-01

Seattle Pacific University is the recent recipient of a NSF CCLI grant to improve student learning in introductory physics and calculus courses. This talk will outline the goals of this collaborative project and present some initial results on student performance. Results from research-based assessments will be presented as well as specific examples of successes and challenges from mechanics and electricity and magnetism.

A stirling engine computer model for performance calculations

NASA Technical Reports Server (NTRS)

Tew, R.; Jefferies, K.; Miao, D.

1978-01-01

To support the development of the Stirling engine as a possible alternative to the automobile spark-ignition engine, the thermodynamic characteristics of the Stirling engine were analyzed and modeled on a computer. The modeling techniques used are presented. The performance of an existing rhombic-drive Stirling engine was simulated by use of this computer program, and some typical results are presented. Engine tests are planned in order to evaluate this model.

Pulse-rate discrimination by cochlear-implant and normal-hearing listeners with and without binaural cues

PubMed Central

Carlyon, Robert P.; Long, Christopher J.; Deeks, John M.

2008-01-01

Experiment 1 measured rate discrimination of electric pulse trains by bilateral cochlear implant (CI) users, for standard rates of 100, 200, and 300 pps. In the diotic condition the pulses were presented simultaneously to the two ears. Consistent with previous results with unilateral stimulation, performance deteriorated at higher standard rates. In the signal interval of each trial in the dichotic condition, the standard rate was presented to the left ear and the (higher) signal rate was presented to the right ear; the non-signal intervals were the same as in the diotic condition. Performance in the dichotic condition was better for some listeners than in the diotic condition for standard rates of 100 and 200 pps, but not at 300 pps. It is concluded that the deterioration in rate discrimination observed for CI users at high rates cannot be alleviated by the introduction of a binaural cue, and is unlikely to be limited solely by central pitch processes. Experiment 2 performed an analogous experiment in which 300-pps acoustic pulse trains were bandpass filtered (3900-5400 Hz) and presented in a noise background to normal-hearing listeners. Unlike the results of experiment 1, performance was superior in the dichotic than in the diotic condition. PMID:18397032

Comparative Investigation of Shared Filesystems for the LHCb Online Cluster

NASA Astrophysics Data System (ADS)

Vijay Kartik, S.; Neufeld, Niko

2012-12-01

This paper describes the investigative study undertaken to evaluate shared filesystem performance and suitability in the LHCb Online environment. Particular focus is given to the measurements and field tests designed and performed on an in-house OpenAFS setup; related comparisons with NFSv4 and GPFS (a clustered filesystem from IBM) are presented. The motivation for the investigation and the test setup arises from the need to serve common user-space like home directories, experiment software and control areas, and clustered log areas. Since the operational requirements on such user-space are stringent in terms of read-write operations (in frequency and access speed) and unobtrusive data relocation, test results are presented with emphasis on file-level performance, stability and “high-availability” of the shared filesystems. Use cases specific to the experiment operation in LHCb, including the specific handling of shared filesystems served to a cluster of 1500 diskless nodes, are described. Issues of prematurely expiring authenticated sessions are explicitly addressed, keeping in mind long-running analysis jobs on the Online cluster. In addition, quantitative test results are also presented with alternatives including NFSv4. Comparative measurements of filesystem performance benchmarks are presented, which are seen to be used as reference for decisions on potential migration of the current storage solution deployed in the LHCb online cluster.

Driver Behavior and Performance with Augmented Reality Pedestrian Collision Warning: An Outdoor User Study.

PubMed

Kim, Hyungil; Gabbard, Joseph L; Anon, Alexandre Miranda; Misu, Teruhisa

2018-04-01

This article investigates the effects of visual warning presentation methods on human performance in augmented reality (AR) driving. An experimental user study was conducted in a parking lot where participants drove a test vehicle while braking for any cross traffic with assistance from AR visual warnings presented on a monoscopic and volumetric head-up display (HUD). Results showed that monoscopic displays can be as effective as volumetric displays for human performance in AR braking tasks. The experiment also demonstrated the benefits of conformal graphics, which are tightly integrated into the real world, such as their ability to guide drivers' attention and their positive consequences on driver behavior and performance. These findings suggest that conformal graphics presented via monoscopic HUDs can enhance driver performance by leveraging the effectiveness of monocular depth cues. The proposed approaches and methods can be used and further developed by future researchers and practitioners to better understand driver performance in AR as well as inform usability evaluation of future automotive AR applications.

Space station MSFC-DPD-235/DR no. CM-03 specification, modular space station project, Part 1 CEI

NASA Technical Reports Server (NTRS)

1971-01-01

Contract engineering item specifications for the modular space station are presented. These specifications resulted from the development and allocations of requirements which are concise statements of performance or constraints on performance. Specifications contain requirements for functional performance and for the verification of design solutions.

Emotional Intelligence and its Relationship with Gender, Academic Performance and Intellectual Abilities of Undergraduates

ERIC Educational Resources Information Center

Valadez Sierra, Maria de los Dolores; Borges del Rosal, Maria Africa; Ruvalcaba Romero, Norma; Villegas, Karina; Lorenzo, Maryurena

2013-01-01

Introduction: Emotional intelligence has been linked to several variables, such as gender, and academic performance. In the area of high intellectual abilities, the literature shows controversy, without a unanimous result on the relationship between both variables. In the present study we analyzed the modulatory effect has academic performance in…

Conveying the Performance Appraisal: The Research and Its Implications.

ERIC Educational Resources Information Center

Wilson, Gerald L.

Results of an examination of research literature on performance-appraisal interviewing and its implications are presented in this report. The appraisal interview functions to (1) provide feedback on performance, (2) counsel and provide help, (3) discover what the employee is thinking, (4) teach the employee to solve problems, (5) help the employee…

JOB PERFORMANCE AIDS AND THEIR IMPACT ON MANPOWER UTILIZATION.

ERIC Educational Resources Information Center

CHALUPSKY, ALBERT B.; KOPF, THOMAS J.

THE PURPOSE OF THE STUDY WAS TO REVIEW AND SYNTHESIZE THE RESULTS OF RESEARCH ON JOB PERFORMANCE AIDS AND EXPLORE THEIR CURRENT AND POTENTIAL ON INDUSTRIAL MANPOWER UTILIZATION. JOB PERFORMANCE AIDS ARE AUXILIARY INFORMATION STORAGE DEVICES WHICH PRESENT JOB INSTRUCTIONS OR REFERENCE DATA FOR USE BY THE EMPLOYEE DURING THE COURSE OF HIS JOB…

Summary Results of the 1980 NACUBO Comparative Performance Study and Investment Questionnaire.

ERIC Educational Resources Information Center

National Association of College and University Business Officers, Washington, DC.

This summary report contains information on the investments of college and university funds. It is the tenth annual study in the series by the National Association of College and University Business Officers (NACUBO). Sections present data and brief analysis on investment performance and endowment characteristics. Under investment performance,…

The Use of the Position Analysis Questionnaire in Selecting Correlates of Job Performance Among Mentally Retarded Workers

ERIC Educational Resources Information Center

And Others; Townsend, J. William

1974-01-01

The present study investigated the efficiency of various existing measures, mainly psychological tests, for predicting job performance of mentally retarded workers in a sheltered occupational shop. Results indicated that existing measures are predictive of performance on some but not all jobs in a sheltered workshop. (Author)

Impact of Metacognitive Awareness on Performance of Students in Chemistry

ERIC Educational Resources Information Center

Rahman, Fazal ur; Jumani, Nabi Bux; Chaudry, Muhammad Ajmal; Chisti, Saeed ul Hasan; Abbasi, Fahim

2010-01-01

The impact of metacognitive awareness on students' performance has been examined in the present study. 900 students of grade X participated in the study. Metacognitive awareness was measured using inventory, while performance of students was measured with the help of researcher made test in the subject of chemistry. Results indicated that…

NUMERICAL FLOW AND TRANSPORT SIMULATIONS SUPPORTING THE SALTSTONE FACILITY PERFORMANCE ASSESSMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flach, G.

2009-02-28

The Saltstone Disposal Facility Performance Assessment (PA) is being revised to incorporate requirements of Section 3116 of the Ronald W. Reagan National Defense Authorization Act for Fiscal Year 2005 (NDAA), and updated data and understanding of vault performance since the 1992 PA (Cook and Fowler 1992) and related Special Analyses. A hybrid approach was chosen for modeling contaminant transport from vaults and future disposal cells to exposure points. A higher resolution, largely deterministic, analysis is performed on a best-estimate Base Case scenario using the PORFLOW numerical analysis code. a few additional sensitivity cases are simulated to examine alternative scenarios andmore » parameter settings. Stochastic analysis is performed on a simpler representation of the SDF system using the GoldSim code to estimate uncertainty and sensitivity about the Base Case. This report describes development of PORFLOW models supporting the SDF PA, and presents sample results to illustrate model behaviors and define impacts relative to key facility performance objectives. The SDF PA document, when issued, should be consulted for a comprehensive presentation of results.« less

Estimation and optimization of thermal performance of evacuated tube solar collector system

NASA Astrophysics Data System (ADS)

Dikmen, Erkan; Ayaz, Mahir; Ezen, H. Hüseyin; Küçüksille, Ecir U.; Şahin, Arzu Şencan

2014-05-01

In this study, artificial neural networks (ANNs) and adaptive neuro-fuzzy (ANFIS) in order to predict the thermal performance of evacuated tube solar collector system have been used. The experimental data for the training and testing of the networks were used. The results of ANN are compared with ANFIS in which the same data sets are used. The R2-value for the thermal performance values of collector is 0.811914 which can be considered as satisfactory. The results obtained when unknown data were presented to the networks are satisfactory and indicate that the proposed method can successfully be used for the prediction of the thermal performance of evacuated tube solar collectors. In addition, new formulations obtained from ANN are presented for the calculation of the thermal performance. The advantages of this approaches compared to the conventional methods are speed, simplicity, and the capacity of the network to learn from examples. In addition, genetic algorithm (GA) was used to maximize the thermal performance of the system. The optimum working conditions of the system were determined by the GA.

A performance study of the time-varying cache behavior: a study on APEX, Mantevo, NAS, and PARSEC

DOE PAGES

Siddique, Nafiul A.; Grubel, Patricia A.; Badawy, Abdel-Hameed A.; ...

2017-09-20

Cache has long been used to minimize the latency of main memory accesses by storing frequently used data near the processor. Processor performance depends on the underlying cache performance. Therefore, significant research has been done to identify the most crucial metrics of cache performance. Although the majority of research focuses on measuring cache hit rates and data movement as the primary cache performance metrics, cache utilization is significantly important. We investigate the application’s locality using cache utilization metrics. In addition, we present cache utilization and traditional cache performance metrics as the program progresses providing detailed insights into the dynamic applicationmore » behavior on parallel applications from four benchmark suites running on multiple cores. We explore cache utilization for APEX, Mantevo, NAS, and PARSEC, mostly scientific benchmark suites. Our results indicate that 40% of the data bytes in a cache line are accessed at least once before line eviction. Also, on average a byte is accessed two times before the cache line is evicted for these applications. Moreover, we present runtime cache utilization, as well as, conventional performance metrics that illustrate a holistic understanding of cache behavior. To facilitate this research, we build a memory simulator incorporated into the Structural Simulation Toolkit (Rodrigues et al. in SIGMETRICS Perform Eval Rev 38(4):37–42, 2011). Finally, our results suggest that variable cache line size can result in better performance and can also conserve power.« less

A performance study of the time-varying cache behavior: a study on APEX, Mantevo, NAS, and PARSEC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siddique, Nafiul A.; Grubel, Patricia A.; Badawy, Abdel-Hameed A.

Cache has long been used to minimize the latency of main memory accesses by storing frequently used data near the processor. Processor performance depends on the underlying cache performance. Therefore, significant research has been done to identify the most crucial metrics of cache performance. Although the majority of research focuses on measuring cache hit rates and data movement as the primary cache performance metrics, cache utilization is significantly important. We investigate the application’s locality using cache utilization metrics. In addition, we present cache utilization and traditional cache performance metrics as the program progresses providing detailed insights into the dynamic applicationmore » behavior on parallel applications from four benchmark suites running on multiple cores. We explore cache utilization for APEX, Mantevo, NAS, and PARSEC, mostly scientific benchmark suites. Our results indicate that 40% of the data bytes in a cache line are accessed at least once before line eviction. Also, on average a byte is accessed two times before the cache line is evicted for these applications. Moreover, we present runtime cache utilization, as well as, conventional performance metrics that illustrate a holistic understanding of cache behavior. To facilitate this research, we build a memory simulator incorporated into the Structural Simulation Toolkit (Rodrigues et al. in SIGMETRICS Perform Eval Rev 38(4):37–42, 2011). Finally, our results suggest that variable cache line size can result in better performance and can also conserve power.« less

Effect of type of noise and loudspeaker array on the performance of omnidirectional and directional microphones.

PubMed

Valente, Michael; Mispagel, Karen M; Tchorz, Juergen; Fabry, David

2006-06-01

Differences in performance between omnidirectional and directional microphones were evaluated between two loudspeaker conditions (single loudspeaker at 180 degrees; diffuse using eight loudspeakers set 45 degrees apart) and two types of noise (steady-state HINT noise; R-Space restaurant noise). Twenty-five participants were fit bilaterally with Phonak Perseo hearing aids using the manufacturer's recommended procedure. After wearing the hearing aids for one week, the parameters were fine-tuned based on subjective comments. Four weeks later, differences in performance between omnidirectional and directional microphones were assessed using HINT sentences presented at 0 degrees with the two types of background noise held constant at 65 dBA and under the two loudspeaker conditions. Results revealed significant differences in Reception Thresholds for Sentences (RTS in dB) where directional performance was significantly better than omnidirectional. Performance in the 180 degrees condition was significantly better than the diffuse condition, and performance was significantly better using the HINT noise in comparison to the R-Space restaurant noise. In addition, results revealed that within each loudspeaker array, performance was significantly better for the directional microphone. Looking across loudspeaker arrays, however, significant differences were not present in omnidirectional performance, but directional performance was significantly better in the 180 degrees condition when compared to the diffuse condition. These findings are discussed in terms of results reported in the past and counseling patients on the potential advantages of directional microphones as the listening situation and type of noise changes.

Spatial resolution requirements for soft-copy reporting in digital radiography

NASA Astrophysics Data System (ADS)

Davies, Andrew G.; Cowen, Arnold R.; Fowler, Richard C.; Bury, Robert F.; Parkin, Geoff J. S.; Lintott, David J.; Martinez, Delia; Safudim, Asif

1996-04-01

The issue of the spatial resolution required in order to present diagnostic quality digital images, especially for softcopy reporting, has received much attention over recent years. The aim of this study was to compare the diagnostic performance reporting from hardcopy and optimized softcopy image presentations. One-hundred-fifteen radiographs of the hand acquired on a photostimulable phosphor computed radiography (CR) system were chosen as the image material. The study group was taken from patients who demonstrated subtle erosions of the bone in the digits. The control group consisted of radiologically normal bands. The images were presented in three modes, the CR system's hardcopy output, and softcopy presentations at full and half spatial resolutions. Four consultant radiologists participated as observers. Results were analyzed using the receiver operating characteristic (ROC) technique, and showed a statistically significant improvement in observer performance for both softcopy formats, when compared to the hardcopy presentation. However, no significant difference in observer performance was found between the two softcopy presentations. We therefore conclude that, with appropriate attention to the processing and presentation of digital image data, softcopy reporting can, for most examinations, provide superior diagnostic performance, even for images viewed at modest (1 k2) resolutions.

Development, evaluation and application of performance-based brake testing technologies field test : executive summary

DOT National Transportation Integrated Search

1999-09-01

This report presents the results of the field test portion of the Development, Evaluation, and Application of Performance-Based Brake Testing Technologies sponsored by the Federal Highway Administrations (FHWA) Office of Motor Carriers.

Results of the U. S. Geological Survey's analytical evaluation program for standard reference samples distributed in April 2001

USGS Publications Warehouse

Woodworth, M.T.; Connor, B.F.

2001-01-01

This report presents the results of the U.S. Geological Survey's analytical evaluation program for six standard reference samples -- T-165 (trace constituents), M-158 (major constituents), N-69 (nutrient constituents), N-70 (nutrient constituents), P-36 (low ionic-strength constituents), and Hg-32 (mercury) -- that were distributed in April 2001 to laboratories enrolled in the U.S. Geological Survey sponsored interlaboratory testing program. Analytical data received from 73 laboratories were evaluated with respect to overall laboratory performance and relative laboratory performance for each analyte in the six reference samples. Results of these evaluations are presented in tabular form. Also presented are tables and graphs summarizing the analytical data provided by each laboratory for each analyte in the six standard reference samples. The most probable value for each analyte was determined using nonparametric statistics.

Model-Based Speech Signal Coding Using Optimized Temporal Decomposition for Storage and Broadcasting Applications

NASA Astrophysics Data System (ADS)

Athaudage, Chandranath R. N.; Bradley, Alan B.; Lech, Margaret

2003-12-01

A dynamic programming-based optimization strategy for a temporal decomposition (TD) model of speech and its application to low-rate speech coding in storage and broadcasting is presented. In previous work with the spectral stability-based event localizing (SBEL) TD algorithm, the event localization was performed based on a spectral stability criterion. Although this approach gave reasonably good results, there was no assurance on the optimality of the event locations. In the present work, we have optimized the event localizing task using a dynamic programming-based optimization strategy. Simulation results show that an improved TD model accuracy can be achieved. A methodology of incorporating the optimized TD algorithm within the standard MELP speech coder for the efficient compression of speech spectral information is also presented. The performance evaluation results revealed that the proposed speech coding scheme achieves 50%-60% compression of speech spectral information with negligible degradation in the decoded speech quality.

Results of the U. S. Geological Survey's Analytical Evaluation Program for Standard Reference Samples Distributed in March 2002

USGS Publications Warehouse

Woodworth, M.T.; Conner, B.F.

2002-01-01

This report presents the results of the U.S. Geological Survey's analytical evaluation program for six standard reference samples -- T- 169 (trace constituents), M- 162 (major constituents), N-73 (nutrient constituents), N-74 (nutrient constituents), P-38 (low ionic-strength constituents), and Hg-34 (mercury) -- that were distributed in March 2002 to laboratories enrolled in the U.S. Geological Survey sponsored intedaboratory testing program. Analytical data received from 93 laboratories were evaluated with respect to overall laboratory performance and relative laboratory performance for each analyte in the six reference samples. Results of these evaluations are presented in tabular form. Also presented are tables and graphs summarizing the analytical data provided by each laboratory for each analyte in the six standard reference samples. The most probable value for each analyte was determined using nonparametric statistics.

Results of the U.S. Geological Survey's analytical evaluation program for standard reference samples distributed in September 2002

USGS Publications Warehouse

Woodworth, Mark T.; Connor, Brooke F.

2003-01-01

This report presents the results of the U.S. Geological Survey's analytical evaluation program for six standard reference samples -- T-171 (trace constituents), M-164 (major constituents), N-75 (nutrient constituents), N-76 (nutrient constituents), P-39 (low ionic-strength constituents), and Hg-35 (mercury) -- that were distributed in September 2002 to laboratories enrolled in the U.S. Geological Survey sponsored interlaboratory testing program. Analytical data received from 102 laboratories were evaluated with respect to overall laboratory performance and relative laboratory performance for each analyte in the six reference samples. Results of these evaluations are presented in tabular form. Also presented are tables and graphs summarizing the analytical data provided by each laboratory for each analyte in the six standard reference samples. The most probable value for each analyte was determined using nonparametric statistics.

Results of the U.S. Geological Survey's analytical evaluation program for standard reference samples distributed in September 2001

USGS Publications Warehouse

Woodworth, Mark T.; Connor, Brooke F.

2002-01-01

This report presents the results of the U.S. Geological Survey's analytical evaluation program for six standard reference samples -- T-167 (trace constituents), M-160 (major constituents), N-71 (nutrient constituents), N-72 (nutrient constituents), P-37 (low ionic-strength constituents), and Hg-33 (mercury) -- that were distributed in September 2001 to laboratories enrolled in the U.S. Geological Survey sponsored interlaboratory testing program. Analytical data received from 98 laboratories were evaluated with respect to overall laboratory performance and relative laboratory performance for each analyte in the six reference samples. Results of these evaluations are presented in tabular form. Also presented are tables and graphs summarizing the analytical data provided by each laboratory for each analyte in the six standard reference samples. The most probable value for each analyte was determined using nonparametric statistics.

Results of the U.S. Geological Survey's Analytical Evaluation Program for Standard Reference Samples Distributed in March 2000

USGS Publications Warehouse

Farrar, Jerry W.; Copen, Ashley M.

2000-01-01

This report presents the results of the U.S. Geological Survey's analytical evaluation program for six standard reference samples -- T-161 (trace constituents), M-154 (major constituents), N-65 (nutrient constituents), N-66 nutrient constituents), P-34 (low ionic strength constituents), and Hg-30 (mercury) -- that were distributed in March 2000 to 144 laboratories enrolled in the U.S. Geological Survey sponsored interlaboratory testing program. Analytical data that were received from 132 of the laboratories were evaluated with respect to overall laboratory performance and relative laboratory performance for each analyte in the six reference samples. Results of these evaluations are presented in tabular form. Also presented are tables and graphs summarizing the analytical data provided by each laboratory for each analyte in the six standard reference samples. The most probable value for each analyte was determined using nonparametric statistics.

Results of the U.S. Geological Survey's analytical evaluation program for standard reference samples distributed in October 1999

USGS Publications Warehouse

Farrar, T.W.

2000-01-01

This report presents the results of the U.S. Geological Survey's analytical evaluation program for six standard reference samples -- T-159 (trace constituents), M-152 (major constituents), N-63 (nutrient constituents), N-64 (nutrient constituents), P-33 (low ionic strength constituents), and Hg-29 (mercury) -- that were distributed in October 1999 to 149 laboratories enrolled in the U.S. Geological Survey sponsored interlaboratory testing program. Analytical data that were received from 131 of the laboratories were evaluated with respect to overall laboratory performance and relative laboratory performance for each analyte in the six reference samples. Results of these evaluations are presented in tabular form. Also presented are tables and graphs summarizing the analytical data provided by each laboratory for each analyte in the six standard reference samples. The most probable value for each analyte was determined using nonparametric statistics.

Results of the U.S. Geological Survey's analytical evaluation program for standard reference samples distributed in March 2003

USGS Publications Warehouse

Woodworth, Mark T.; Connor, Brooke F.

2003-01-01

This report presents the results of the U.S. Geological Survey's analytical evaluation program for six standard reference samples -- T-173 (trace constituents), M-166 (major constituents), N-77 (nutrient constituents), N-78 (nutrient constituents), P-40 (low ionic-strength constituents), and Hg-36 (mercury) -- that were distributed in March 2003 to laboratories enrolled in the U.S. Geological Survey sponsored interlaboratory testing program. Analytical data received from 110 laboratories were evaluated with respect to overall laboratory performance and relative laboratory performance for each analyte in the six reference samples. Results of these evaluations are presented in tabular form. Also presented are tables and graphs summarizing the analytical data provided by each laboratory for each analyte in the six standard reference samples. The most probable value for each analyte was determined using nonparametric statistics.

Results of the U. S. Geological Survey's analytical evaluation program for standard reference samples distributed in October 2000

USGS Publications Warehouse

Connor, B.F.; Currier, J.P.; Woodworth, M.T.

2001-01-01

This report presents the results of the U.S. Geological Survey's analytical evaluation program for six standard reference samples -- T-163 (trace constituents), M-156 (major constituents), N-67 (nutrient constituents), N-68 (nutrient constituents), P-35 (low ionic strength constituents), and Hg-31 (mercury) -- that were distributed in October 2000 to 126 laboratories enrolled in the U.S. Geological Survey sponsored interlaboratory testing program. Analytical data that were received from 122 of the laboratories were evaluated with respect to overall laboratory performance and relative laboratory performance for each analyte in the six reference samples. Results of these evaluations are presented in tabular form. Also presented are tables and graphs summarizing the analytical data provided by each laboratory for each analyte in the six standard reference samples. The most probable value for each analyte was determined using nonparametric statistics.

Performance analysis of Aloha networks with power capture and near/far effect

NASA Astrophysics Data System (ADS)

McCartin, Joseph T.

1989-06-01

An analysis is presented for the throughput characteristics for several classes of Aloha packet networks. Specifically, the throughput for variable packet length Aloha utilizing multiple power levels to induce receiver capture is derived. The results are extended to an analysis of a selective-repeat ARQ Aloha network. Analytical results are presented which indicate a significant increase in throughput for a variable packet network implementing a random two power level capture scheme. Further research into the area of the near/far effect on Aloha networks is included. Improvements in throughput for mobile radio Aloha networks which are subject to the near/far effect are presented. Tactical Command, Control and Communications (C3) systems of the future will rely on Aloha ground mobile data networks. The incorporation of power capture and the near/far effect into future tactical networks will result in improved system analysis, design, and performance.

Mod-2 wind turbine project assessment and cluster test plans

NASA Technical Reports Server (NTRS)

Gordon, L. H.

1982-01-01

An assessment of the Mod-2 Wind Turbine project is presented based on initial goals and present results. Specifically, the Mod-2 background, project flow, and a chronology of events/results leading to Mod-2 acceptance is presented. After checkout/acceptance of the three operating turbines, NASA/LeRC will continue management of a two year test program performed at the DOE Goodnoe Hills test site. This test program is expected to yield data necessary for the continued development and optimization of wind energy systems. These test activities, the implementation of, and the results to date are also presented.

Reading Rate and Comprehension for Text Presented on Tablet and Paper: Evidence from Arabic.

PubMed

Hermena, Ehab W; Sheen, Mercedes; AlJassmi, Maryam; AlFalasi, Khulood; AlMatroushi, Maha; Jordan, Timothy R

2017-01-01

The effectiveness of tablet computers to supplement or replace paper-based text in everyday life has yet to be fully revealed. Previous investigations comparing reading performance using tablets and paper have, however, reported inconsistent results. Furthermore, the interpretability of some previous findings is limited by lack of experimental control over variables like text display conditions. In the current study, we investigated reading performance for text presented on tablet and paper. Crucially, the levels of luminance and contrast were matched precisely across tablet and paper. The study used Arabic text which differs substantially from the languages used previously to investigate effects of tablet and paper on reading, thus offering a distinctive test of the influence of these two media on reading performance. The results suggest that when text display conditions are well-matched, there is no reliable difference in reading performance between the two media. Also, neither the order of medium (reading from tablet or paper first), nor familiarity with using a tablet significantly influence reading performance. These results call into question previous suggestions that reading from tablets is linked to poorer reading performance, and demonstrate the benefits of controlling text display conditions. These findings are of interest to reading scientists and educators.

Reading Rate and Comprehension for Text Presented on Tablet and Paper: Evidence from Arabic

PubMed Central

Hermena, Ehab W.; Sheen, Mercedes; AlJassmi, Maryam; AlFalasi, Khulood; AlMatroushi, Maha; Jordan, Timothy R.

2017-01-01

The effectiveness of tablet computers to supplement or replace paper-based text in everyday life has yet to be fully revealed. Previous investigations comparing reading performance using tablets and paper have, however, reported inconsistent results. Furthermore, the interpretability of some previous findings is limited by lack of experimental control over variables like text display conditions. In the current study, we investigated reading performance for text presented on tablet and paper. Crucially, the levels of luminance and contrast were matched precisely across tablet and paper. The study used Arabic text which differs substantially from the languages used previously to investigate effects of tablet and paper on reading, thus offering a distinctive test of the influence of these two media on reading performance. The results suggest that when text display conditions are well-matched, there is no reliable difference in reading performance between the two media. Also, neither the order of medium (reading from tablet or paper first), nor familiarity with using a tablet significantly influence reading performance. These results call into question previous suggestions that reading from tablets is linked to poorer reading performance, and demonstrate the benefits of controlling text display conditions. These findings are of interest to reading scientists and educators. PMID:28270791

Steady and unsteady three-dimensional transonic flow computations by integral equation method

NASA Technical Reports Server (NTRS)

Hu, Hong

1994-01-01

This is the final technical report of the research performed under the grant: NAG1-1170, from the National Aeronautics and Space Administration. The report consists of three parts. The first part presents the work on unsteady flows around a zero-thickness wing. The second part presents the work on steady flows around non-zero thickness wings. The third part presents the massively parallel processing implementation and performance analysis of integral equation computations. At the end of the report, publications resulting from this grant are listed and attached.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fischer, W.; Shiota, T.

Two categories of NaS traction batteries will be discussed: the present battery of Asea Brown Boveri and Powerplex and potential future NaS traction batteries. A large number of our present 24 kWh - 35 kw battery has been subjected to bench and on-vehicle performance tests. Test results will be presented. Future battery types to be volume produced in the early 1990`s are discussed with regard to energy, power and shape for special applications such a passenger car and van propulsion. Examples for those batteries will be given and projected performance characteristiques will be discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fischer, W.; Shiota, T.

Two categories of NaS traction batteries will be discussed: the present battery of Asea Brown Boveri and Powerplex and potential future NaS traction batteries. A large number of our present 24 kWh - 35 kw battery has been subjected to bench and on-vehicle performance tests. Test results will be presented. Future battery types to be volume produced in the early 1990's are discussed with regard to energy, power and shape for special applications such a passenger car and van propulsion. Examples for those batteries will be given and projected performance characteristiques will be discussed.

Advanced TIL system for laser beam focusing in a turbulent regime

NASA Astrophysics Data System (ADS)

Sprangle, Phillip A.; Ting, Antonio C.; Kaganovich, Dmitry; Khizhnyak, Anatoliy I.; Tomov, Ivan V.; Markov, Vladimir B.; Korobkin, Dmitriy V.

2014-10-01

This paper discusses an advanced target in the loop (ATIL) system with its performance based on a nonlinear phase conjugation scheme that performs rapid adjustment of the laser beam wavefront to mitigate effects associated with atmospheric turbulence along the propagation path. The ATIL method allows positional control of the laser spot (the beacon) on a remote imaged-resolved target. The size of this beacon is governed by the reciprocity of two counterpropagating beams (one towards the target and another scattered by the target) and the fidelity of the phase conjugation scheme. In this presentation we will present the results of the thorough analysis of ATIL operation, factors that affect its performance, its focusing efficiency and the comparison of laboratory experimental validation and computer simulation results.

Clinical experience with vestibular schwannomas: epidemiology, symptomatology, diagnosis, and surgical results.

PubMed

Tos, M; Charabi, S; Thomsen, J

1998-01-01

The Danish model for vestibular schwannoma (VS) surgery has been influenced by some historical otological events, taking its origin in the fact that the first attempt to remove CPA tumors was performed by an otologist in 1916. In approximately 50 years VS surgery was performed by neurosurgeons in a decentralized model. Highly specialized neuro- and otosurgeons have been included in our team since the early beginning of the centralized Danish model of VS surgery in 1976. Our surgical practice has always been performed on the basis of known and proven knowledge, but we spared no effort to search for innovative procedures. The present paper reflects the experience we have gained in two decades of VS surgery. Our studies on the incidence, symptomatology, diagnosis, expectancy and surgical results are presented.

Student laboratory presentations as a learning tool in anatomy education.

PubMed

Chollet, Madeleine B; Teaford, Mark F; Garofalo, Evan M; DeLeon, Valerie B

2009-01-01

Previous studies have shown that anatomy students who complete oral laboratory presentations believe they understand the material better and retain it longer than they otherwise would if they only took examinations on the material; however, we have found no studies that empirically test such outcomes. The purpose of this study was to assess the effectiveness of oral presentations through comparisons with other methods of assessment, most notably, examination performance. Specifically, we tested whether students (n = 256) performed better on examination questions on topics covered by their oral presentations than on other topics. Each student completed two graded, 12-minute laboratory presentations on two different assigned topics during the course and took three examinations, each of which covered a third of the course material. Examination questions were characterized by type (memorization, pathway, analytical, spatial). A two-way repeated measures analysis of variance revealed that students performed better on topics covered by their presentations than on topics not covered by their presentations (P < 0.005), regardless of presentation grade (P > 0.05) and question type (P > 0.05). These results demonstrate empirically that oral presentations are an effective learning tool.

Optimal Doppler centroid estimation for SAR data from a quasi-homogeneous source

NASA Technical Reports Server (NTRS)

Jin, M. Y.

1986-01-01

This correspondence briefly describes two Doppler centroid estimation (DCE) algorithms, provides a performance summary for these algorithms, and presents the experimental results. These algorithms include that of Li et al. (1985) and a newly developed one that is optimized for quasi-homogeneous sources. The performance enhancement achieved by the optimal DCE algorithm is clearly demonstrated by the experimental results.

MSFC Skylab attitude and pointing control system mission evaluation

NASA Technical Reports Server (NTRS)

Chubb, W. B.

1974-01-01

The results of detailed performance analyses of the attitude and pointing control system in-orbit hardware and software on Skylab are reported. Performance is compared with requirements, test results, and prelaunch predictions. A brief history of the altitude and pointing control system evolution leading to the launch configuration is presented. The report states that the attitude and pointing system satisfied all requirements.

The Graphical Display of Simulation Results, with Applications to the Comparison of Robust IRT Estimators of Ability.

ERIC Educational Resources Information Center

Thissen, David; Wainer, Howard

Simulation studies of the performance of (potentially) robust statistical estimation produce large quantities of numbers in the form of performance indices of the various estimators under various conditions. This report presents a multivariate graphical display used to aid in the digestion of the plentiful results in a current study of Item…

Finite wordlength implementation of a megachannel digital spectrum analyzer

NASA Technical Reports Server (NTRS)

Satorius, E. H.; Grimm, M. J.; Zimmerman, G. A.; Wilck, H. C.

1986-01-01

The results of an extensive system analysis of the megachannel spectrum analyzer currently being developed for use in various applications of the Deep Space Network are presented. The intent of this analysis is to quantify the effects of digital quantization errors on system performance. The results of this analysis provide useful guidelines for choosing various system design parameters to enhance system performance.

Small, high pressure liquid hydrogen turbopump

NASA Technical Reports Server (NTRS)

Csomor, A.; Warren, D. J.

1980-01-01

A high pressure, low capacity, liquid hydrogen turbopump was designed, fabricated, and tested. The design configuration of the turbopump is summarized and the results of the analytical and test efforts are presented. Approaches used to pin point the cause of poor suction performance with the original design are described and performance data are included with an axial inlet design which results in excellent suction capability.

Performance assessment in algebra learning process

NASA Astrophysics Data System (ADS)

Lestariani, Ida; Sujadi, Imam; Pramudya, Ikrar

2017-12-01

The purpose of research to describe the implementation of performance assessment on algebra learning process. The subject in this research is math educator of SMAN 1 Ngawi class X. This research includes descriptive qualitative research type. Techniques of data collecting are done by observation method, interview, and documentation. Data analysis technique is done by data reduction, data presentation, and conclusion. The results showed any indication that the steps taken by the educator in applying the performance assessment are 1) preparing individual worksheets and group worksheets, 2) preparing rubric assessments for independent worksheets and groups and 3) making performance assessments rubric to learners’ performance results with individual or groups task.

Effect of physical workload and modality of information presentation on pattern recognition and navigation task performance by high-fit young males.

PubMed

Zahabi, Maryam; Zhang, Wenjuan; Pankok, Carl; Lau, Mei Ying; Shirley, James; Kaber, David

2017-11-01

Many occupations require both physical exertion and cognitive task performance. Knowledge of any interaction between physical demands and modalities of cognitive task information presentation can provide a basis for optimising performance. This study examined the effect of physical exertion and modality of information presentation on pattern recognition and navigation-related information processing. Results indicated males of equivalent high fitness, between the ages of 18 and 34, rely more on visual cues vs auditory or haptic for pattern recognition when exertion level is high. We found that navigation response time was shorter under low and medium exertion levels as compared to high intensity. Navigation accuracy was lower under high level exertion compared to medium and low levels. In general, findings indicated that use of the haptic modality for cognitive task cueing decreased accuracy in pattern recognition responses. Practitioner Summary: An examination was conducted on the effect of physical exertion and information presentation modality in pattern recognition and navigation. In occupations requiring information presentation to workers, who are simultaneously performing a physical task, the visual modality appears most effective under high level exertion while haptic cueing degrades performance.

Decoupling Actions from Consequences: Dorsal Hippocampal Lesions Facilitate Instrumental Performance, but Impair Behavioral Flexibility in Rats

PubMed Central

Busse, Sebastian; Schwarting, Rainer K. W.

2016-01-01

The present study is part of a series of experiments, where we analyze why and how damage of the rat’s dorsal hippocampus (dHC) can enhance performance in a sequential reaction time task (SRTT). In this task, sequences of distinct visual stimulus presentations are food-rewarded in a fixed-ratio-13-schedule. Our previous study (Busse and Schwarting, 2016) had shown that rats with lesions of the dHC show substantially shorter session times and post-reinforcement pauses (PRPs) than controls, which allows for more practice when daily training is kept constant. Since sequential behavior is based on instrumental performance, a sequential benefit might be secondary to that. In order to test this hypothesis in the present study, we performed two experiments, where pseudorandom rather than sequential stimulus presentation was used in rats with excitotoxic dorsal hippocampal lesions. Again, we found enhanced performance in the lesion-group in terms of shorter session times and PRPs. During the sessions we found that the lesion-group spent less time with non-instrumental behavior (i.e., grooming, sniffing, and rearing) after prolonged instrumental training. Also, such rats showed moderate evidence for an extinction impairment under devalued food reward conditions and significant deficits in a response-outcome (R-O)-discrimination task in comparison to a control-group. These findings suggest that facilitatory effects on instrumental performance after dorsal hippocampal lesions may be primarily a result of complex behavioral changes, i.e., reductions of behavioral flexibility and/or alterations in motivation, which then result in enhanced instrumental learning. PMID:27375453

Flight test results of the strapdown hexad inertial reference unit (SIRU). Volume 2: Test report

NASA Technical Reports Server (NTRS)

Hruby, R. J.; Bjorkman, W. S.

1977-01-01

Results of flight tests of the Strapdown Inertial Reference Unit (SIRU) navigation system are presented. The fault tolerant SIRU navigation system features a redundant inertial sensor unit and dual computers. System software provides for detection and isolation of inertial sensor failures and continued operation in the event of failures. Flight test results include assessments of the system's navigational performance and fault tolerance. Performance shortcomings are analyzed.

Space shuttle Ku-band integrated rendezvous radar/communications system study

NASA Technical Reports Server (NTRS)

1976-01-01

The results are presented of work performed on the Space Shuttle Ku-Band Integrated Rendezvous Radar/Communications System Study. The recommendations and conclusions are included as well as the details explaining the results. The requirements upon which the study was based are presented along with the predicted performance of the recommended system configuration. In addition, shuttle orbiter vehicle constraints (e.g., size, weight, power, stowage space) are discussed. The tradeoffs considered and the operation of the recommended configuration are described for an optimized, integrated Ku-band radar/communications system. Basic system tradeoffs, communication design, radar design, antenna tradeoffs, antenna gimbal and drive design, antenna servo design, and deployed assembly packaging design are discussed. The communications and radar performance analyses necessary to support the system design effort are presented. Detailed derivations of the communications thermal noise error, the radar range, range rate, and angle tracking errors, and the communications transmitter distortion parameter effect on crosstalk between the unbalanced quadriphase signals are included.

Formulation and implementation of nonstationary adaptive estimation algorithm with applications to air-data reconstruction

NASA Technical Reports Server (NTRS)

Whitmore, S. A.

1985-01-01

The dynamics model and data sources used to perform air-data reconstruction are discussed, as well as the Kalman filter. The need for adaptive determination of the noise statistics of the process is indicated. The filter innovations are presented as a means of developing the adaptive criterion, which is based on the true mean and covariance of the filter innovations. A method for the numerical approximation of the mean and covariance of the filter innovations is presented. The algorithm as developed is applied to air-data reconstruction for the space shuttle, and data obtained from the third landing are presented. To verify the performance of the adaptive algorithm, the reconstruction is also performed using a constant covariance Kalman filter. The results of the reconstructions are compared, and the adaptive algorithm exhibits better performance.

EMC Test Report Electrodynamic Dust Shield

NASA Technical Reports Server (NTRS)

Carmody, Lynne M.; Boyette, Carl B.

2014-01-01

This report documents the Electromagnetic Interference E M I evaluation performed on the Electrodynamic Dust Shield (EDS) which is part of the MISSE-X System under the Electrostatics and Surface Physics Laboratory at Kennedy Space Center. Measurements are performed to document the emissions environment associated with the EDS units. The purpose of this report is to collect all information needed to reproduce the testing performed on the Electrodynamic Dust Shield units, document data gathered during testing, and present the results. This document presents information unique to the measurements performed on the Bioculture Express Rack payload; using test methods prepared to meet SSP 30238 requirements. It includes the information necessary to satisfy the needs of the customer per work order number 1037104. The information presented herein should only be used to meet the requirements for which it was prepared.

Results from an audit feedback strategy for chronic obstructive pulmonary disease in-hospital care: a joint analysis from the AUDIPOC and European COPD audit studies.

PubMed

Lopez-Campos, Jose Luis; Asensio-Cruz, M Isabel; Castro-Acosta, Ady; Calero, Carmen; Pozo-Rodriguez, Francisco

2014-01-01

Clinical audits have emerged as a potential tool to summarize the clinical performance of healthcare over a specified period of time. However, the effectiveness of audit and feedback has shown inconsistent results and the impact of audit and feedback on clinical performance has not been evaluated for COPD exacerbations. In the present study, we analyzed the results of two consecutive nationwide clinical audits performed in Spain to evaluate both the in-hospital clinical care provided and the feedback strategy. The present study is an analysis of two clinical audits performed in Spain that evaluated the clinical care provided to COPD patients who were admitted to the hospital for a COPD exacerbation. The first audit was performed from November-December 2008. The feedback strategy consisted of personalized reports for each participant center, the presentation and discussion of the results at regional, national and international meetings and the creation of health-care quality standards for COPD. The second audit was part of a European study during January and February 2011. The impact of the feedback strategy was evaluated in term of clinical care provided and in-hospital survival. A total of 94 centers participated in the two audits, recruiting 8,143 admissions (audit 1∶3,493 and audit 2∶4,650). The initially provided clinical care was reasonably acceptable even though there was considerable variability. Several diagnostic and therapeutic procedures improved in the second audit. Although the differences were significant, the degree of improvement was small to moderate. We found no impact on in-hospital mortality. The present study describes COPD hospital care in Spanish hospitals and evaluates the impact of peer-benchmarked, individually written and group-oral feedback strategy on the clinical outcomes for treating COPD exacerbations. It describes small to moderate improvements in the clinical care provided to COPD patients with no impact on in-hospital mortality.

Design and Demonstration of Emergency Control Modes for Enhanced Engine Performance

NASA Technical Reports Server (NTRS)

Liu, Yuan; Litt, Jonathan S.; Guo, Ten-Huei

2013-01-01

A design concept is presented for developing control modes that enhance aircraft engine performance during emergency flight scenarios. The benefits of increased engine performance to overall vehicle survivability during these situations may outweigh the accompanied elevated risk of engine failure. The objective involves building control logic that can consistently increase engine performance beyond designed maximum levels based on an allowable heightened probability of failure. This concept is applied to two previously developed control modes: an overthrust mode that increases maximum engine thrust output and a faster response mode that improves thrust response to dynamic throttle commands. This paper describes the redesign of these control modes and presents simulation results demonstrating both enhanced engine performance and robust maintenance of the desired elevated risk level.

Determination of the Minimum Use Level of Fuel System Icing Inhibitor (FSII) in JP-8 That Will Provide Adquate Icing Inhibition and Biostatic Protection for Air Force Aircraft

DTIC Science & Technology

2013-12-01

experimental studies and analyses performed and the resulting recommendations. Results from the present effort indicated that a minimum use limit of... experimental studies performed and the resulting recommendations regarding the minimum on-board use limit of FSII while maintaining safe operability...sumping. A detailed summary of the experimental efforts and results are provided in a separate report (Balster et al., 2010). For the ATCC

A Comparative Study of Performance in the Conners' Continuous Performance Test between Brazilian and North American Children

ERIC Educational Resources Information Center

Miranda, Monica Carolina; Sinnes, Elaine Girao; Pompeia, Sabine; Bueno, Orlando Francisco Amodeo

2008-01-01

Objective: The present study investigated the performance of Brazilian children in the Continuous Performance Test, CPT-II, and compared results to those of the norms obtained in the United States. Method: The U.S. norms were compared to those of a Brazilian sample composed of 6- to 11-year-olds separated into 4 age-groups (half boys) that…

Development and performance evaluation of an MR squeeze-mode damper

NASA Astrophysics Data System (ADS)

Sapiński, Bogdan; Gołdasz, Janusz

2015-11-01

In this paper the authors present results of a magnetorheological (MR) damper prototype development and performance evaluation study. The damper is a device functioning in the so-called squeeze-mode of MR fluid flow regime of operation. By principle, in a squeeze-mode damper the control (working) gap height varies according to the prescribed displacement or force input profile. Such hardware has been claimed to be well suited to small-amplitude vibration damping applications. However, it is still in its infancy. Its potential seems appealing yet unclear. Accordingly, the authors reveal performance figures of the damper complemented by numerical finite-element simulations of the electro-magnetic circuit of the device. The numerical results are presented in the form of maps of averaged magnetic flux density versus coil current and gap height as well as magnetic flux, inductance, and cogging force calculations, respectively. The simulated data are followed by experimental evaluation of the damper performance incorporating plots of force versus piston displacement (velocity) across a prescribed range of excitation inputs. Moreover, some insight into transient (unsteady) characteristics of the device is provided through testing results involving transient currents.

Performance Characteristics of a Cross-Flow Hydrokinetic Turbine under Unsteady Conditions

NASA Astrophysics Data System (ADS)

Flack, Karen; Lust, Ethan; Bailin, Ben

2017-11-01

Performance characteristics are presented for a cross-flow hydrokinetic turbine designed for use in a riverine environment. The test turbine is a 1:6 scale model of a three-bladed device (9.5 m span, 6.5 m diameter) that has been proposed by the Department of Energy. Experiments are conducted in the large towing tank (116 m long, 7.9 m wide, 5 m deep) at the United States Naval Academy. The turbine is towed beneath a moving carriage at a constant speed in combination with a shaft motor to achieve the desired tip speed ratio (TSR) range. The measured quantities of turbine thrust, torque and RPM result in power and thrust coefficients for a range of TSR. Results will be presented for cases with quiescent flow at a range of Reynolds numbers and flow with mild surface waves, representative of riverine environments. The impact of unsteady flow conditions on the average turbine performance was not significant. Unsteady flow conditions did have an impact on instantaneous turbine performance which operationally would result in unsteady blade loading and instantaneous power quality.

New technology in turbine aerodynamics

NASA Technical Reports Server (NTRS)

Glassman, A. J.; Moffitt, T. P.

1972-01-01

A cursory review is presented of some of the recent work that has been done in turbine aerodynamic research at NASA-Lewis Research Center. Topics discussed include the aerodynamic effect of turbine coolant, high work-factor (ratio of stage work to square of blade speed) turbines, and computer methods for turbine design and performance prediction. An extensive bibliography is included. Experimental cooled-turbine aerodynamics programs using two-dimensional cascades, full annular cascades, and cold rotating turbine stage tests are discussed with some typical results presented. Analytically predicted results for cooled blade performance are compared to experimental results. The problems and some of the current programs associated with the use of very high work factors for fan-drive turbines of high-bypass-ratio engines are discussed. Turbines currently being investigated make use of advanced blading concepts designed to maintain high efficiency under conditions of high aerodynamic loading. Computer programs have been developed for turbine design-point performance, off-design performance, supersonic blade profile design, and the calculation of channel velocities for subsonic and transonic flow fields. The use of these programs for the design and analysis of axial and radial turbines is discussed.

Pediatric Eye Screening Instrumentation

NASA Astrophysics Data System (ADS)

Chen, Ying-Ling; Lewis, J. W. L.

2001-11-01

Computational evaluations are presented for binocular eye screening using the off-axis digital retinascope. The retinascope, such as the iScreen digital screening system, has been employed to perform pediatric binocular screening using a flash lamp and single-shot camera recording. The digital images are transferred electronically to a reading center for analysis. The method has been shown to detect refractive error, amblyopia, anisocoria, and ptosis. This computational work improves the performance of the system and forms the basis for automated data analysis. For this purpose, variouis published eye models are evaluated with simulated retinascope images. Two to ten million rays are traced in each image calculation. The poster will present the simulation results for a range of eye conditions of refractive error of -20 to +20 diopters with 0.5- to-1 diopter resolution, pupil size of 3 to 8 mm diameter (1-mm increment), and staring angle of 2 to 12 degree (2-degree increment). The variation of the results with the system conditions such as the off-axis distance of light source and the shutter size of camera are also evaluated. The quantitative analysis for each eye’s and system’s condition is then performed to obtain parameters for automatic reading. The summary of the system performance is given and performance-enhancement design modifications are presented.

Taguchi Based Performance and Reliability Improvement of an Ion Chamber Amplifier for Enhanced Nuclear Reactor Safety

NASA Astrophysics Data System (ADS)

Kulkarni, R. D.; Agarwal, Vivek

2008-08-01

An ion chamber amplifier (ICA) is used as a safety device for neutronic power (flux) measurement in regulation and protection systems of nuclear reactors. Therefore, performance reliability of an ICA is an important issue. Appropriate quality engineering is essential to achieve a robust design and performance of the ICA circuit. It is observed that the low input bias current operational amplifiers used in the input stage of the ICA circuit are the most critical devices for proper functioning of the ICA. They are very sensitive to the gamma radiation present in their close vicinity. Therefore, the response of the ICA deteriorates with exposure to gamma radiation resulting in a decrease in the overall reliability, unless desired performance is ensured under all conditions. This paper presents a performance enhancement scheme for an ICA operated in the nuclear environment. The Taguchi method, which is a proven technique for reliability enhancement, has been used in this work. It is demonstrated that if a statistical, optimal design approach, like the Taguchi method is used, the cost of high quality and reliability may be brought down drastically. The complete methodology and statistical calculations involved are presented, as are the experimental and simulation results to arrive at a robust design of the ICA.

Performance under dichoptic versus binocular viewing conditions - Effects of attention and task requirements

NASA Technical Reports Server (NTRS)

Kimchi, Ruth; Gopher, Daniel; Rubin, Yifat; Raij, David

1993-01-01

Three experiments investigated subjects' ability to allocate attention and cope with task requirements under dichoptic versus binocular viewing conditions. Experiments 1 and 2 employed a target detection task in compound and noncompound stimuli, and Experiment 3 employed a relative-proximity judgment task. The tasks were performed in a focused attention condition in which subjects had to attend to the stimulus presented to one eye or field (under dichoptic and binocular viewing conditions, respectively) while ignoring the stimulus presented to the other eye or field, and in a divided attention condition in which subjects had to attend to the stimuli presented to both eyes or fields. Subjects' performance was affected by the interaction of attention conditions with task requirements, but it was generally the same under dichoptic and binocular viewing conditions. The more dependent the task was on finer discrimination, the more performance was impaired by divided attention. These results suggest that at least with discrete tasks and relatively short exposure durations, performance when each eye is presented with a separate stimulus is the same as when the entire field of stimulation is viewed by both eyes.

Structural Model for the Effects of Environmental Elements on the Psychological Characteristics and Performance of the Employees of Manufacturing Systems

PubMed Central

Realyvásquez, Arturo; Maldonado-Macías, Aidé Aracely; García-Alcaraz, Jorge; Cortés-Robles, Guillermo; Blanco-Fernández, Julio

2016-01-01

This paper analyzes the effects of environmental elements on the psychological characteristics and performance of employees in manufacturing systems using structural equation modeling. Increasing the comprehension of these effects may help optimize manufacturing systems regarding their employees’ psychological characteristics and performance from a macroergonomic perspective. As the method, a new macroergonomic compatibility questionnaire (MCQ) was developed and statistically validated, and 158 respondents at four manufacture companies were considered. Noise, lighting and temperature, humidity and air quality (THAQ) were used as independent variables and psychological characteristics and employees’ performance as dependent variables. To propose and test the hypothetical causal model of significant relationships among the variables, a data analysis was deployed. Results found that the macroergonomic compatibility of environmental elements presents significant direct effects on employees’ psychological characteristics and either direct or indirect effects on the employees’ performance. THAQ had the highest direct and total effects on psychological characteristics. Regarding the direct and total effects on employees’ performance, the psychological characteristics presented the highest effects, followed by THAQ conditions. These results may help measure and optimize manufacturing systems’ performance by enhancing their macroergonomic compatibility and quality of life at work of the employees. PMID:26742054

Structural Model for the Effects of Environmental Elements on the Psychological Characteristics and Performance of the Employees of Manufacturing Systems.

PubMed

Realyvásquez, Arturo; Maldonado-Macías, Aidé Aracely; García-Alcaraz, Jorge; Cortés-Robles, Guillermo; Blanco-Fernández, Julio

2016-01-05

This paper analyzes the effects of environmental elements on the psychological characteristics and performance of employees in manufacturing systems using structural equation modeling. Increasing the comprehension of these effects may help optimize manufacturing systems regarding their employees' psychological characteristics and performance from a macroergonomic perspective. As the method, a new macroergonomic compatibility questionnaire (MCQ) was developed and statistically validated, and 158 respondents at four manufacture companies were considered. Noise, lighting and temperature, humidity and air quality (THAQ) were used as independent variables and psychological characteristics and employees' performance as dependent variables. To propose and test the hypothetical causal model of significant relationships among the variables, a data analysis was deployed. Results found that the macroergonomic compatibility of environmental elements presents significant direct effects on employees' psychological characteristics and either direct or indirect effects on the employees' performance. THAQ had the highest direct and total effects on psychological characteristics. Regarding the direct and total effects on employees' performance, the psychological characteristics presented the highest effects, followed by THAQ conditions. These results may help measure and optimize manufacturing systems' performance by enhancing their macroergonomic compatibility and quality of life at work of the employees.

Comparing electrochemical performance of transition metal silicate cathodes and chevrel phase Mo6S8 in the analogous rechargeable Mg-ion battery system

NASA Astrophysics Data System (ADS)

Chen, Xinzhi; Bleken, Francesca L.; Løvvik, Ole Martin; Vullum-Bruer, Fride

2016-07-01

Polyanion based silicate materials, MgMSiO4 (M = Fe, Mn, Co), previously reported to be promising cathode materials for Mg-ion batteries, have been re-examined. Both the sol-gel and molten salt methods are employed to synthesize MgMSiO4 composites. Mo6S8 is synthesized by a molten salt method combined with Cu leaching and investigated in the equivalent electrochemical system as a bench mark. Electrochemical measurements for Mo6S8 performed using the 2nd generation electrolyte show similar results to those reported in literature. Electrochemical performance of the silicate materials on the other hand, do not show the promising results previously reported. A thorough study of these published results are presented here, and compared to the current experimental data on the same material system. It appears that there are certain inconsistencies in the published results which cannot be explained. To further corroborate the present experimental results, atomic-scale calculations from first principles are performed, demonstrating that diffusion barriers are very high for Mg diffusion in MgMSiO4. In conclusion, MgMSiO4 (M = Fe, Mn, Co) olivine materials do not seem to be such good candidates for cathode materials in Mg-ion batteries as previously reported.

U.S. GASOLINE COMPOSITION STUDY

EPA Science Inventory

This presentation presents results from a 2004/2005 study of U.S. gasoline composition. Differences in composition are driven by regulation, octane requirements, refining methods, and performance needs. Major differences in composition were traced to a few compounds: benzene, MTB...

Transit Bus Fuel Economy and Performance Simulation

DOT National Transportation Integrated Search

1984-01-01

This report presents the results of bus simulation studies to determine the effects of various design and operating parameters on bus fuel economy and performance. The bus components are first described in terms of how they are modeled. Then a variat...

Evaluation of AAFE apparatus to measure residual and transient convection in zero-gravity

NASA Technical Reports Server (NTRS)

Ruff, R. C.; Facemire, B. R.; Witherow, W. K.

1978-01-01

An evaluation apparatus which photographs convective and diffusive flows in crystal growth experiments is presented. Results in the following catagories are reported: (1) Human factors; (2) Electrical and mechanical; (3) Optical performance; and (4) Thermal performance.

Concept for a Satellite-Based Advanced Air Traffic Management System : Volume 10. Subsystem Performance Requirements.

DOT National Transportation Integrated Search

1974-02-01

The volume presents the results of the subsystem performance requirements study for an Advanced Air Traffic Management System (AATMS). The study determined surveillance and navigation subsystem requirements for terminal and enroute area operations. I...

A data encryption solution for mobile health apps in cooperation environments.

PubMed

Silva, Bruno M; Rodrigues, Joel J P C; Canelo, Fábio; Lopes, Ivo C; Zhou, Liang

2013-04-25

Mobile Health (mHealth) proposes health care delivering anytime and anywhere. It aims to answer several emerging problems in health services, including the increasing number of chronic diseases, high costs on national health services, and the need to provide direct access to health services, regardless of time and place. mHealth systems include the use of mobile devices and apps that interact with patients and caretakers. However, mobile devices present several constraints, such as processor, energy, and storage resource limitations. The constant mobility and often-required Internet connectivity also exposes and compromises the privacy and confidentiality of health information. This paper presents a proposal, construction, performance evaluation, and validation of a data encryption solution for mobile health apps (DE4MHA), considering a novel and early-proposed cooperation strategy. The goal was to present a robust solution based on encryption algorithms that guarantee the best confidentiality, integrity, and authenticity of users health information. In this paper, we presented, explained, evaluated the performance, and discussed the cooperation mechanisms and the proposed encryption solution for mHealth apps. First, we designed and deployed the DE4MHA. Then two studies were performed: (1) study and comparison of symmetric and asymmetric encryption/decryption algorithms in an mHealth app under a cooperation environment, and (2) performance evaluation of the DE4MHA. Its performance was evaluated through a prototype using an mHealth app for obesity prevention and cares, called SapoFit. We then conducted an evaluation study of the mHealth app with cooperation mechanisms and the DE4MHA using real users and a real cooperation scenario. In 5 days, 5 different groups of 7 students selected randomly agreed to use and experiment the SapoFit app using the 7 devices available for trials. There were 35 users of SapoFit that participated in this study. The performance evaluation of the app was done using 7 real mobile devices in 5 different days. The results showed that confidentiality and protection of the users' health information was guaranteed and SapoFit users were able to use the mHealth app with satisfactory quality. Results also showed that the app with the DE4MHA presented nearly the same results as the app without the DE4MHA. The performance evaluation results considered the probability that a request was successfully answered as a function of the number of uncooperative nodes in the network. The service delivery probability decreased with the increase of uncooperative mobile nodes. Using DE4MHA, it was observed that performance presented a slightly worse result. The service average was also slightly worse but practically insignificantly different than with DE4MHA, being considered negligible. This paper proposed a data encryption solution for mobile health apps, called DE4MHA. The data encryption algorithm DE4MHA with cooperation mechanisms in mobile health allow users to safely obtain health information with the data being carried securely. These security mechanisms did not deteriorate the overall network performance and the app, maintaining similar performance levels as without the encryption. More importantly, it offers a robust and reliable increase of privacy, confidentiality, integrity, and authenticity of their health information. Although it was experimented on a specific mHealth app, SapoFit, both DE4MHA and the cooperation strategy can be deployed in other mHealth apps.

Constraints on Ho from Time-Delay Measurements of PG1115+080

NASA Technical Reports Server (NTRS)

Chartas, George

2003-01-01

The observations that were performed as part of the award titled: Constraints on Ho From Time-Delay Measurements of PG1115+080 resulted in several scientific publications and presentations. We list these publications and presentations and provide brief description of the important science presented in them.

Validation of the Information/Communications Technology Literacy Test

DTIC Science & Technology

2016-10-01

nested set. Table 11 presents the results of incremental validity analyses for job knowledge/performance criteria by MOS. Figure 7 presents much...Systems Operator-Analyst (25B) and Nodal Network Systems Operator-Maintainer (25N) MOS. This report documents technical procedures and results of the...research effort. Results suggest that the ICTL test has potential as a valid and highly efficient predictor of valued outcomes in Signal school MOS. Not

Ejecta Particle Size Distributions for Shock Loaded Sn And Al Targets

DTIC Science & Technology

1999-06-01

respectively. For the first time, particle distributions that results from microjet production will be presented. Results from these experiments will...performed. For the first time, particle size distributions that result from microjet production will be presented. The energy in the microjets will...the metal to break up as a shock wave moves through the material. The figure also shows that if there are surface finish variations, microjets will

The versatility of a truss mounted mobile transporter for in-space construction

NASA Technical Reports Server (NTRS)

Bush, Harold G.; Lake, Mark S.; Watson, Judith J.; Heard, Walter L., Jr.

1988-01-01

The Mobile Transporter (MT) evolution from early erectable structures assembly activities is detailed. The MT operational features which are required to support astronauts performing on-orbit structure construction or spacecraft assembly functions are presented and discussed. Use of the MT to perform a variety of assembly functions is presented. Estimated EVA assembly times for a precision segmented reflector approximately 20 m in diameter are presented. The EVA/MT technique under study for construction of the reflector (and the entire spacecraft) is illustrated. Finally, the current status of development activities and test results involving the MT and Space Station structural assembly are presented.

Dataset of two experiments of the application of gamified peer assessment model into online learning environment MeuTutor.

PubMed

Tenório, Thyago; Bittencourt, Ig Ibert; Isotani, Seiji; Pedro, Alan; Ospina, Patrícia; Tenório, Daniel

2017-06-01

In this dataset, we present the collected data of two experiments with the application of the gamified peer assessment model into online learning environment MeuTutor to allow the comparison of the obtained results with others proposed models. MeuTutor is an intelligent tutoring system aims to monitor the learning of the students in a personalized way, ensuring quality education and improving the performance of its members (Tenório et al., 2016) [1]. The first experiment evaluated the effectiveness of the peer assessment model through metrics as final grade (result), time to correct the activities and associated costs. The second experiment evaluated the gamification influence into peer assessment model, analyzing metrics as access number (logins), number of performed activities and number of performed corrections. In this article, we present in table form for each metric: the raw data of each treatment; the summarized data; the application results of the normality test Shapiro-Wilk; the application results of the statistical tests T -Test and/or Wilcoxon. The presented data in this article are related to the article entitled "A gamified peer assessment model for on-line learning environments in a competitive context" (Tenório et al., 2016) [1].

Predictive control and estimation algorithms for the NASA/JPL 70-meter antennas

NASA Technical Reports Server (NTRS)

Gawronski, W.

1991-01-01

A modified output prediction procedure and a new controller design is presented based on the predictive control law. Also, a new predictive estimator is developed to complement the controller and to enhance system performance. The predictive controller is designed and applied to the tracking control of the Deep Space Network 70 m antennas. Simulation results show significant improvement in tracking performance over the linear quadratic controller and estimator presently in use.

Design fabrication and installation of a yaw measuring device

NASA Technical Reports Server (NTRS)

1979-01-01

The results of work performed in the development and testing of a yaw measuring device are summarized. A review of the yaw measurement method; and the techniques and hardware needed for its implementation are presented. A description and summary of the tests performed at the U.S. Bureau of Mines Bruceton facility are included. Conclusions are summarized and recommendations for a unit capable of operation in a mine environment are presented.

Mechanical performance of porous concrete pavement containing nano black rice husk ash

NASA Astrophysics Data System (ADS)

Ibrahim, M. Y. Mohd; Ramadhansyah, P. J.; Rosli, H. Mohd; Ibrahim, M. H. Wan

2018-01-01

This paper presents an experimental research on the performance of nano black rice husk ash on the porous concrete pavement properties. The performance of the porous concrete pavement mixtures was investigated based on their compressive strength, flexural strength, and splitting tensile strength. The results indicated that using nano material from black rice husk ash improved the mechanical properties of porous concrete pavement. In addition, the result of compressive, flexural, and splitting tensile strength was increased with increasing in curing age. Finally, porous concrete pavement with 10% replacement levels exhibited an excellent performance with good strength compared to others.

Conversion of cardiac performance data in analog form for digital computer entry

NASA Technical Reports Server (NTRS)

Miller, R. L.

1972-01-01

A system is presented which will reduce analog cardiac performance data and convert the results to digital form for direct entry into a commercial time-shared computer. Circuits are discussed which perform the measurement and digital conversion of instantaneous systolic and diastolic parameters from the analog blood pressure waveform. Digital averaging over a selected number of heart cycles is performed on these measurements, as well as those of flow and heart rate. The determination of average cardiac output and peripheral resistance, including trends, is the end result after processing by digital computer.

Determination of efficiencies, loss mechanisms, and performance degradation factors in chopper controlled dc vehical motors. Section 1: Test program results and recommendations

NASA Technical Reports Server (NTRS)

Hamilton, H. B.; Strangas, E.

1980-01-01

The conventional series motor model is discussed as well as procedures for obtaining, by test, the parameters necessary for calculating performance and losses. The calculated results for operation from ripple free DC are compared with observed test results, indicating approximately 5% or less error. Experimental data indicating the influence of brush shift and chopper frequency are also presented. Both factors have a significant effect on the speed and torque relationships. The losses and loss mechanisms present in a DC series motor are examined and an attempt is made to evaluate the added losses due to harmonic currents and fluxes. Findings with respect to these losses is summarized.

Hydrocarbon group type determination in jet fuels by high performance liquid chromatography

NASA Technical Reports Server (NTRS)

Antoine, A. C.

1977-01-01

Results are given for the analysis of some jet and diesel fuel samples which were prepared from oil shale and coal syncrudes. Thirty-two samples of varying chemical composition and physical properties were obtained. Hydrocarbon types in these samples were determined by fluorescent indicator adsorption (FIA) analysis, and the results from three laboratories are presented and compared. Recently, rapid high performance liquid chromatography (HPLC) methods have been proposed for hydrocarbon group type analysis, with some suggestion for their use as a replacement of the FIA technique. Two of these methods were used to analyze some of the samples, and these results are also presented and compared. Two samples of petroleum-based Jet A fuel are similarly analyzed.

Young children's coding and storage of visual and verbal material.

PubMed

Perlmutter, M; Myers, N A

1975-03-01

36 preschool children (mean age 4.2 years) were each tested on 3 recognition memory lists differing in test mode (visual only, verbal only, combined visual-verbal). For one-third of the children, original list presentation was visual only, for another third, presentation was verbal only, and the final third received combined visual-verbal presentation. The subjects generally performed at a high level of correct responding. Verbal-only presentation resulted in less correct recognition than did either visual-only or combined visual-verbal presentation. However, because performances under both visual-only and combined visual-verbal presentation were statistically comparable, and a high level of spontaneous labeling was observed when items were presented only visually, a dual-processing conceptualization of memory in 4-year-olds was suggested.

Optimum performance and potential flow field of hovering rotors

NASA Technical Reports Server (NTRS)

Wu, J. C.; Sigman, R. K.

1975-01-01

Rotor and propeller performance and induced potential flowfields were studied on the basis of a rotating actuator disk concept, with special emphasis on rotors hovering out of ground effect. A new theory for the optimum performance of rotors hovering OGE is developed and presented. An extended theory for the optimum performance of rotors and propellers in axial motion is also presented. Numerical results are presented for the optimum distributions of blade-bound circulation together with axial inflow and ultimate wake velocities for the hovering rotor over the range of thrust coefficient of interest in rotorcraft applications. Shapes of the stream tubes and of the velocities in the slipstream are obtained, using available methods, for optimum and off-optimum circulation distributions for rotors hovering in and out of ground effect. A number of explicit formulae useful in computing rotor and propeller induced flows are presented for stream functions and velocities due to distributions of circular vortices over axi-symmetric surfaces.

Novel Observer Scheme of Fuzzy-MRAS Sensorless Speed Control of Induction Motor Drive

NASA Astrophysics Data System (ADS)

Chekroun, S.; Zerikat, M.; Mechernene, A.; Benharir, N.

2017-01-01

This paper presents a novel approach Fuzzy-MRAS conception for robust accurate tracking of induction motor drive operating in a high-performance drives environment. Of the different methods for sensorless control of induction motor drive the model reference adaptive system (MRAS) finds lot of attention due to its good performance. The analysis of the sensorless vector control system using MRAS is presented and the resistance parameters variations and speed observer using new Fuzzy Self-Tuning adaptive IP Controller is proposed. In fact, fuzzy logic is reminiscent of human thinking processes and natural language enabling decisions to be made based on vague information. The present approach helps to achieve a good dynamic response, disturbance rejection and low to plant parameter variations of the induction motor. In order to verify the performances of the proposed observer and control algorithms and to test behaviour of the controlled system, numerical simulation is achieved. Simulation results are presented and discussed to shown the validity and the performance of the proposed observer.

Tests of commercial colour CMOS cameras for astronomical applications

NASA Astrophysics Data System (ADS)

Pokhvala, S. M.; Reshetnyk, V. M.; Zhilyaev, B. E.

2013-12-01

We present some results of testing commercial colour CMOS cameras for astronomical applications. Colour CMOS sensors allow to perform photometry in three filters simultaneously that gives a great advantage compared with monochrome CCD detectors. The Bayer BGR colour system realized in colour CMOS sensors is close to the astronomical Johnson BVR system. The basic camera characteristics: read noise (e^{-}/pix), thermal noise (e^{-}/pix/sec) and electronic gain (e^{-}/ADU) for the commercial digital camera Canon 5D MarkIII are presented. We give the same characteristics for the scientific high performance cooled CCD camera system ALTA E47. Comparing results for tests of Canon 5D MarkIII and CCD ALTA E47 show that present-day commercial colour CMOS cameras can seriously compete with the scientific CCD cameras in deep astronomical imaging.

Characterizing Detonating LX-17 Charges Crossing a Transverse Air Gap with Experiments and Modeling

NASA Astrophysics Data System (ADS)

Lauderbach, Lisa M.; Souers, P. Clark; Garcia, Frank; Vitello, Peter; Vandersall, Kevin S.

2009-12-01

Experiments were performed using detonating LX-17 (92.5% TATB, 7.5% Kel-F by weight) charges with various width transverse air gaps with manganin peizoresistive in-situ gauges present. The experiments, performed with 25 mm diameter by 25 mm long LX-17 pellets with the transverse air gap in between, showed that transverse gaps up to about 3 mm could be present without causing the detonation wave to fail to continue as a detonation. The Tarantula/JWL++ code was utilized to model the results and compare with the in-situ gauge records with some agreement to the experimental data with additional work needed for a better match to the data. This work will present the experimental details as well as comparison to the model results.

Competition and Performance: More Facts, More Understanding? Comment on Murayama and Elliot (2012)

ERIC Educational Resources Information Center

Johnson, David W.; Johnson, Roger T.; Roseth, Cary J.

2012-01-01

Murayama and Elliot (2012) made a significant contribution to the literature on competition by presenting the results of 2 meta-analyses and 3 primary studies on the relation between competition and performance. Murayama and Elliot established that in general, there is no relationship between competition and performance. They then made the case…

DSN telemetry system performance with convolutionally code data

NASA Technical Reports Server (NTRS)

Mulhall, B. D. L.; Benjauthrit, B.; Greenhall, C. A.; Kuma, D. M.; Lam, J. K.; Wong, J. S.; Urech, J.; Vit, L. D.

1975-01-01

The results obtained to date and the plans for future experiments for the DSN telemetry system were presented. The performance of the DSN telemetry system in decoding convolutionally coded data by both sequential and maximum likelihood techniques is being determined by testing at various deep space stations. The evaluation of performance models is also an objective of this activity.

Infrared horizon sensor modeling for attitude determination and control: Analysis and mission experience

NASA Technical Reports Server (NTRS)

Phenneger, M. C.; Singhal, S. P.; Lee, T. H.; Stengle, T. H.

1985-01-01

The work performed by the Attitude Determination and Control Section at the National Aeronautics and Space Administration/Goddard Space Flight Center in analyzing and evaluating the performance of infrared horizon sensors is presented. The results of studies performed during the 1960s are reviewed; several models for generating the Earth's infrared radiance profiles are presented; and the Horizon Radiance Modeling Utility, the software used to model the horizon sensor optics and electronics processing to computer radiance-dependent attitude errors, is briefly discussed. Also provided is mission experience from 12 spaceflight missions spanning the period from 1973 to 1984 and using a variety of horizon sensing hardware. Recommendations are presented for future directions for the infrared horizon sensing technology.

Trends in high performance compressors for petrochemical and natural gas industry in China

NASA Astrophysics Data System (ADS)

Zhao, Yuanyang; Li, Liansheng

2015-08-01

Compressors are the key equipment in the petrochemical and natural gas industry system. The performance and reliability of them are very important for the process system. The application status of petrochemical & natural gas compressors in China is presented in this paper. The present status of design and operating technologies of compressors in China are mentioned in this paper. The turbo, reciprocating and twin screw compressors are discussed. The market demands for different structure compressors in process gas industries are analysed. This paper also introduces the research and developments for high performance compressors in China. The recent research results on efficiency improvement methods, stability improvement, online monitor and fault diagnosis will also be presented in details.

Assessment of simulation fidelity using measurements of piloting technique in flight. II

NASA Technical Reports Server (NTRS)

Ferguson, S. W.; Clement, W. F.; Hoh, R. H.; Cleveland, W. B.

1985-01-01

Two components of the Vertical Motion Simulator (presently being used to assess the fidelity of UH-60A simulation) are evaluated: (1) the dash/quickstop Nap-of-the-earth (NOE) piloting task, and (2) the bop-up task. Data from these two flight test experiments are presented which provide information on the effect of reduced visual field of view, variation in scene content and texture, and the affect of pure time delay in the closed-loop pilot response. In comparison with task performance results obtained in flight tests, the results from the simulation indicate that the pilot's NOE task performance in the simulator is significantly degraded.

The upwind control volume scheme for unstructured triangular grids

NASA Technical Reports Server (NTRS)

Giles, Michael; Anderson, W. Kyle; Roberts, Thomas W.

1989-01-01

A new algorithm for the numerical solution of the Euler equations is presented. This algorithm is particularly suited to the use of unstructured triangular meshes, allowing geometric flexibility. Solutions are second-order accurate in the steady state. Implementation of the algorithm requires minimal grid connectivity information, resulting in modest storage requirements, and should enhance the implementation of the scheme on massively parallel computers. A novel form of upwind differencing is developed, and is shown to yield sharp resolution of shocks. Two new artificial viscosity models are introduced that enhance the performance of the new scheme. Numerical results for transonic airfoil flows are presented, which demonstrate the performance of the algorithm.

An approach to operating system testing

NASA Technical Reports Server (NTRS)

Sum, R. N., Jr.; Campbell, R. H.; Kubitz, W. J.

1984-01-01

To ensure the reliability and performance of a new system, it must be verified or validated in some manner. Currently, testing is the only resonable technique available for doing this. Part of this testing process is the high level system test. System testing is considered with respect to operating systems and in particular UNIX. This consideration results in the development and presentation of a good method for performing the system test. The method includes derivations from the system specifications and ideas for management of the system testing project. Results of applying the method to the IBM System/9000 XENIX operating system test and the development of a UNIX test suite are presented.

Apollo 16 mission Report. Supplement 1: Apollo 16 guidance, navigation, and control system performance analysis report

NASA Technical Reports Server (NTRS)

1972-01-01

The results are reported of additional studies which were conducted to supplement conclusions drawn in the MSC Mission Report and analyses which were not completed in time to meet the Mission Report dealine. A detailed evaluation of the Abort Guidance System sensor assembly and results from the investigation of the X gyro loop anomaly are included. Further evidence is presented substantiating the excellent LM IMU performance obtained from preliminary indications. A detailed study is presented of the procedural changes implemented on Apollo 16 to diminish the number and duration of interruptions to the CSM DAP attitude maneuver during P20 Option 5 operations.

Mind wandering minimizes mind numbing: Reducing semantic-satiation effects through absorptive lapses of attention.

PubMed

Mooneyham, Benjamin W; Schooler, Jonathan W

2016-08-01

Mind wandering is associated with perceptual decoupling: the disengagement of attention from perception. This decoupling is deleterious to performance in many situations; however, we sought to determine whether it might occur in the service of performance in certain circumstances. In two studies, we examined the role of mind wandering in a test of "semantic satiation," a phenomenon in which the repeated presentation of a word reduces semantic priming for a subsequently presented semantic associate. We posited that the attentional and perceptual decoupling associated with mind wandering would reduce the amount of satiation in the semantic representations of repeatedly presented words, thus leading to a reduced semantic-satiation effect. Our results supported this hypothesis: Self-reported mind-wandering episodes (Study 1) and behavioral indices of decoupled attention (Study 2) were both predictive of maintained semantic priming in situations predicted to induce semantic satiation. Additionally, our results suggest that moderate inattention to repetitive stimuli is not sufficient to enable "dishabituation": the refreshment of cognitive performance that results from diverting attention away from the task at hand. Rather, full decoupling is necessary to reap the benefits of mind wandering and to minimize mind numbing.

The effects of regional insolation differences upon advanced solar thermal electric power plant performance and energy costs

NASA Technical Reports Server (NTRS)

Latta, A. F.; Bowyer, J. M.; Fujita, T.

1979-01-01

This paper presents the performance and cost of four 10-MWe advanced solar thermal electric power plants sited in various regions of the continental United States. Each region has different insolation characteristics which result in varying collector field areas, plant performance, capital costs, and energy costs. The paraboloidal dish, central receiver, cylindrical parabolic trough, and compound parabolic concentrator (CPC) comprise the advanced concepts studied. This paper contains a discussion of the regional insolation data base, a description of the solar systems' performances and costs, and a presentation of a range for the forecast cost of conventional electricity by region and nationally over the next several decades.

Redundancy management of inertial systems.

NASA Technical Reports Server (NTRS)

Mckern, R. A.; Musoff, H.

1973-01-01

The paper reviews developments in failure detection and isolation techniques applicable to gimballed and strapdown systems. It examines basic redundancy management goals of improved reliability, performance and logistic costs, and explores mechanizations available for both input and output data handling. The meaning of redundant system reliability in terms of available coverage, system MTBF, and mission time is presented and the practical hardware performance limitations of failure detection and isolation techniques are explored. Simulation results are presented illustrating implementation coverages attainable considering IMU performance models and mission detection threshold requirements. The implications of a complete GN&C redundancy management method on inertial techniques are also explored.

Adaptive coded aperture imaging in the infrared: towards a practical implementation

NASA Astrophysics Data System (ADS)

Slinger, Chris W.; Gilholm, Kevin; Gordon, Neil; McNie, Mark; Payne, Doug; Ridley, Kevin; Strens, Malcolm; Todd, Mike; De Villiers, Geoff; Watson, Philip; Wilson, Rebecca; Dyer, Gavin; Eismann, Mike; Meola, Joe; Rogers, Stanley

2008-08-01

An earlier paper [1] discussed the merits of adaptive coded apertures for use as lensless imaging systems in the thermal infrared and visible. It was shown how diffractive (rather than the more conventional geometric) coding could be used, and that 2D intensity measurements from multiple mask patterns could be combined and decoded to yield enhanced imagery. Initial experimental results in the visible band were presented. Unfortunately, radiosity calculations, also presented in that paper, indicated that the signal to noise performance of systems using this approach was likely to be compromised, especially in the infrared. This paper will discuss how such limitations can be overcome, and some of the tradeoffs involved. Experimental results showing tracking and imaging performance of these modified, diffractive, adaptive coded aperture systems in the visible and infrared will be presented. The subpixel imaging and tracking performance is compared to that of conventional imaging systems and shown to be superior. System size, weight and cost calculations indicate that the coded aperture approach, employing novel photonic MOEMS micro-shutter architectures, has significant merits for a given level of performance in the MWIR when compared to more conventional imaging approaches.

Space infrared telescope facility wide field and diffraction limited array camera (IRAC)

NASA Technical Reports Server (NTRS)

Fazio, Giovanni G.

1988-01-01

The wide-field and diffraction limited array camera (IRAC) is capable of two-dimensional photometry in either a wide-field or diffraction-limited mode over the wavelength range from 2 to 30 microns with a possible extension to 120 microns. A low-doped indium antimonide detector was developed for 1.8 to 5.0 microns, detectors were tested and optimized for the entire 1.8 to 30 micron range, beamsplitters were developed and tested for the 1.8 to 30 micron range, and tradeoff studies of the camera's optical system performed. Data are presented on the performance of InSb, Si:In, Si:Ga, and Si:Sb array detectors bumpbonded to a multiplexed CMOS readout chip of the source-follower type at SIRTF operating backgrounds (equal to or less than 1 x 10 to the 8th ph/sq cm/sec) and temperature (4 to 12 K). Some results at higher temperatures are also presented for comparison to SIRTF temperature results. Data are also presented on the performance of IRAC beamsplitters at room temperature at both 0 and 45 deg angle of incidence and on the performance of the all-reflecting optical system baselined for the camera.

An empirical assessment of high-performing medical groups: results from a national study.

PubMed

Shortell, Stephen M; Schmittdiel, Julie; Wang, Margaret C; Li, Rui; Gillies, Robin R; Casalino, Lawrence P; Bodenheimer, Thomas; Rundall, Thomas G

2005-08-01

The performance of medical groups is receiving increased attention. Relatively little conceptual or empirical work exists that examines the various dimensions of medical group performance. Using a national database of 693 medical groups, this article develops a scorecard approach to assessing group performance and presents a theory-driven framework for differentiating between high-performing versus low-performing medical groups. The clinical quality of care, financial performance, and organizational learning capability of medical groups are assessed in relation to environmental forces, resource acquisition and resource deployment factors, and a quality-centered culture. Findings support the utility of the performance scorecard approach and identification of a number of key factors differentiating high-performing from low-performing groups including, in particular, the importance of a quality-centered culture and the requirement of outside reporting from third party organizations. The findings hold a number of important implications for policy and practice, and the framework presented provides a foundation for future research.

Presenting self-monitoring test results for consumers: the effects of graphical formats and age.

PubMed

Tao, Da; Yuan, Juan; Qu, Xingda

2018-05-11

To examine the effects of graphical formats and age on consumers' comprehension and perceptions of the use of self-monitoring test results. Participants (36 older and 36 young adults) were required to perform verbatim comprehension and value interpretation tasks with hypothetical self-monitoring test results. The test results were randomly presented by four reference range number lines: basic, color enhanced, color/text enhanced, and personalized information enhanced formats. We measured participants' task performance and eye movement data during task completion, and their perceptions and preference of the graphical formats. The 4 graphical formats yielded comparable task performance, while text/color and personalized information enhanced formats were believed to be easier and more useful in information comprehension, and led to increased confidence in correct comprehension of test results, compared with other formats (all p's < .05). Perceived health risk increased as the formats applied more information cues (p = .008). There were age differences in task performance and visual attention (all p's < .01), while young and older adults had similar perceptions for the 4 formats. Personalized information enhanced format was preferred by both groups. Text/color and personalized information cues appear to be useful for comprehending test results. Future work can be directed to improve the design of graphical formats especially for older adults, and to assess the formats in clinical settings.

Managing for Results in America's Great City Schools. A Report of the Performance Measurement and Benchmarking Project

ERIC Educational Resources Information Center

Council of the Great City Schools, 2012

2012-01-01

"Managing for Results in America's Great City Schools, 2012" is presented by the Council of the Great City Schools to its members and the public. The purpose of the project was and is to develop performance measures that can improve the business operations of urban public school districts nationwide. This year's report includes data from 61 of the…

Over compression influence to the performances of the spark ignition engines

NASA Astrophysics Data System (ADS)

Rakosi, E.; Talif, S. G.; Manolache, G.

2016-08-01

This paper presents the theoretical and experimental results of some procedures used in improving the performances of the automobile spark ignition engines. The study uses direct injection and high over-compression applied to a standard engine. To this purpose, the paper contains both the constructive solutions and the results obtained from the test bed concerning the engine power indices, fuel consumption and exhaust emissions.

Motivation To Learn and Perform.

ERIC Educational Resources Information Center

1997

This document contains four papers from a symposium on motivation to learn and perform in the workplace. "Getting It Together: Motivations and Success Characteristics for Interorganizational Collaborations" (Mary Wilson Callahan) presents results of a literature review, a hierarchical framework of motivations for interorganizational collaboration,…

Polymer-impregnated bridge slabs : performance over 10 years.

DOT National Transportation Integrated Search

1990-01-01

This report presents the results of a study to evaluate the performance over a 10-year period of slabs that were impregnated to a depth of about 1 in with a monomer that was subsequently polymerized (shallow polymer impregnation). The slabs were used...

Certification and verification for Northrup model NSC-01-0732 fresnel lens concentrating solar collector

NASA Technical Reports Server (NTRS)

1979-01-01

Structural analysis and certification of the collector system is presented. System verification against the interim performance criteria is presented and indicated by matrices. The verification discussion, analysis, and test results are also given.

Measuring Visual Displays’ Effect on Novice Performance in Door Gunnery

DTIC Science & Technology

2014-12-01

training in a mixed reality simulation. Specifically, we examined the effect that different visual displays had on novice soldier performance; qualified...there was a main effect of visual display on performance. However, both visual treatment groups experienced the same degree of presence and simulator... The purpose of this paper is to present the results of our recent experimentation involving a novice population performing aerial door gunnery

Method of Matching Performance of Compressor Systems with that of Aircraft Power Sections

NASA Technical Reports Server (NTRS)

Bullock, Robert O.; Keetch, Robert C.; Moses, Jason J.

1945-01-01

A method is developed of easily determining the performance of a compressor system relative to that of the power section for a given altitude. Because compressors, reciprocating engines, and turbines are essentially flow devices, the performance of each of these power-plant components is presented in terms of similar dimensionless ratios. The pressure and temperature changes resulting from restrictions of the charge-air flow and from heat transfer in the ducts connecting the components of the power plant are also expressed by the same dimensionless ratios and the losses are included in the performance of the compressor. The performance of a mechanically driven, single-stage compressor in relation to the performance of a conventional air-cooled engine operating at sea-level conditions is presented as an example of the application of the method.

Thermodynamic analysis of biofuels as fuels for high temperature fuel cells

NASA Astrophysics Data System (ADS)

Milewski, Jarosław; Bujalski, Wojciech; Lewandowski, Janusz

2011-11-01

Based on mathematical modeling and numerical simulations, applicativity of various biofuels on high temperature fuel cell performance are presented. Governing equations of high temperature fuel cell modeling are given. Adequate simulators of both solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) have been done and described. Performance of these fuel cells with different biofuels is shown. Some characteristics are given and described. Advantages and disadvantages of various biofuels from the system performance point of view are pointed out. An analysis of various biofuels as potential fuels for SOFC and MCFC is presented. The results are compared with both methane and hydrogen as the reference fuels. The biofuels are characterized by both lower efficiency and lower fuel utilization factors compared with methane. The presented results are based on a 0D mathematical model in the design point calculation. The governing equations of the model are also presented. Technical and financial analysis of high temperature fuel cells (SOFC and MCFC) are shown. High temperature fuel cells can be fed by biofuels like: biogas, bioethanol, and biomethanol. Operational costs and possible incomes of those installation types were estimated and analyzed. A comparison against classic power generation units is shown. A basic indicator net present value (NPV) for projects was estimated and commented.

Thermodynamic analysis of biofuels as fuels for high temperature fuel cells

NASA Astrophysics Data System (ADS)

Milewski, Jarosław; Bujalski, Wojciech; Lewandowski, Janusz

2013-02-01

Based on mathematical modeling and numerical simulations, applicativity of various biofuels on high temperature fuel cell performance are presented. Governing equations of high temperature fuel cell modeling are given. Adequate simulators of both solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) have been done and described. Performance of these fuel cells with different biofuels is shown. Some characteristics are given and described. Advantages and disadvantages of various biofuels from the system performance point of view are pointed out. An analysis of various biofuels as potential fuels for SOFC and MCFC is presented. The results are compared with both methane and hydrogen as the reference fuels. The biofuels are characterized by both lower efficiency and lower fuel utilization factors compared with methane. The presented results are based on a 0D mathematical model in the design point calculation. The governing equations of the model are also presented. Technical and financial analysis of high temperature fuel cells (SOFC and MCFC) are shown. High temperature fuel cells can be fed by biofuels like: biogas, bioethanol, and biomethanol. Operational costs and possible incomes of those installation types were estimated and analyzed. A comparison against classic power generation units is shown. A basic indicator net present value (NPV) for projects was estimated and commented.

Cervical spine disease may result in a negative lumbar spinal drainage trial in normal pressure hydrocephalus: case report.

PubMed

Komotar, Ricardo J; Zacharia, Brad E; Mocco, J; Kaiser, Michael G; Frucht, Stephen J; McKhann, Guy M

2008-10-01

In this case report, we present a patient with normal pressure hydrocephalus in whom a lumbar drainage trial yielded a false-negative result secondary to cervical spondylosis. An 80-year-old woman presented with classic symptoms of normal pressure hydrocephalus as well as evidence of cervical myelopathy. Magnetic resonance imaging of the brain and spine showed enlarged ventricles and single-level cervical canal narrowing. An initial lumbar drainage trial was performed, which revealed negative results. The patient then underwent cervical decompression and fusion. Despite this procedure, the patient's symptoms continued to worsen. A repeat lumbar drainage trial was performed with positive results. Subsequently, a ventriculoperitoneal shunt was placed, resulting in significant improvement of her symptoms. This case report illustrates how altered cerebrospinal fluid flow dynamics may impact the accuracy of the lumbar spinal drainage trial in patients with normal pressure hydrocephalus.

The effects of clamp torque, humidity, and carbon oxygen poisoning on PEM fuel cell performance

NASA Astrophysics Data System (ADS)

Lee, Woo-Kum

2000-10-01

Proton exchange membrane fuel cell (PEMFC) is attracting much attention as a power source of electric vehicles due to high power density capability. Although there has been much research and development done on PEWC, there are still many problems to be solved. One of the major problems is water management inside the fuel cell. The performance of the fuel cell is strongly influenced by the state of hydration of the membrane. If the membrane is too dry, its conductivity drops resulting in reduced cell performance. An excess of water in the fuel cell can lead to flooding problems, also resulting in performance drop. This dissertation presents experimental data that may be used to verify numerical simulations of a PEM fuel cell. The key to this usefulness is the closure of a water balance in the fuel cell for various operating conditions. The closure results from experimental data showed that the inlet gas streams are not fully saturated with water vapor. Another key to the usefulness of the data is the measurement of the internal compression pressure that is exerted on the gas diffusion layer. Data is presented to show the effect of this compression on the performance of the PEMFC and on the water balance results. Another problem in application of a PEM fuel cell is CO poisoning on the MEA. Gas reformed from methanol or gasoline contains small amount of CO resulting in significant decreasing fuel cell performance. Several recovery techniques were discussed to solve the CO problem. The use of Pt-Ru alloys as anode catalyst has shown that CO is oxidized at more negative potentials as compared to pure Pt. According to the result, an improvement has been achieved at CO level 5 ppm. Another method to prevent CO poisoning has been described by blowing 5% of air into the anode side. The result shows that the performance recovers very quickly as the air is injected during reformate (50 ppm CO).

Effect of variation of length-to-depth ratio and Mach number on the performance of a typical double cavity scramjet combustor

NASA Astrophysics Data System (ADS)

Mahto, Navin Kumar; Choubey, Gautam; Suneetha, Lakka; Pandey, K. M.

2016-11-01

The two equation standard k-ɛ turbulence model and the two-dimensional compressible Reynolds-Averaged Navier-Stokes (RANS) equations have been used to computationally simulate the double cavity scramjet combustor. Here all the simulations are performed by using ANSYS 14-FLUENT code. At the same time, the validation of the present numerical simulation for double cavity has been performed by comparing its result with the available experimental data which is in accordance with the literature. The results are in good agreement with the schlieren image and the pressure distribution curve obtained experimentally. However, the pressure distribution curve obtained numerically is under-predicted in 5 locations by numerical calculation. Further, investigations on the variations of the effects of the length-to-depth ratio of cavity and Mach number on the combustion characteristics has been carried out. The present results show that there is an optimal length-to-depth ratio for the cavity for which the performance of combustor significantly improves and also efficient combustion takes place within the combustor region. Also, the shifting of the location of incident oblique shock took place in the downstream of the H2 inlet when the Mach number value increases. But after achieving a critical Mach number range of 2-2.5, the further increase in Mach number results in lower combustion efficiency which may deteriorate the performance of combustor.

Between-Trial Forgetting Due to Interference and Time in Motor Adaptation.

PubMed

Kim, Sungshin; Oh, Youngmin; Schweighofer, Nicolas

2015-01-01

Learning a motor task with temporally spaced presentations or with other tasks intermixed between presentations reduces performance during training, but can enhance retention post training. These two effects are known as the spacing and contextual interference effect, respectively. Here, we aimed at testing a unifying hypothesis of the spacing and contextual interference effects in visuomotor adaptation, according to which forgetting between trials due to either spaced presentations or interference by another task will promote between-trial forgetting, which will depress performance during acquisition, but will promote retention. We first performed an experiment with three visuomotor adaptation conditions: a short inter-trial-interval (ITI) condition (SHORT-ITI); a long ITI condition (LONG-ITI); and an alternating condition with two alternated opposite tasks (ALT), with the same single-task ITI as in LONG-ITI. In the SHORT-ITI condition, there was fastest increase in performance during training and largest immediate forgetting in the retention tests. In contrast, in the ALT condition, there was slowest increase in performance during training and little immediate forgetting in the retention tests. Compared to these two conditions, in the LONG-ITI, we found intermediate increase in performance during training and intermediate immediate forgetting. To account for these results, we fitted to the data six possible adaptation models with one or two time scales, and with interference in the fast, or in the slow, or in both time scales. Model comparison confirmed that two time scales and some degree of interferences in either time scale are needed to account for our experimental results. In summary, our results suggest that retention following adaptation is modulated by the degree of between-trial forgetting, which is due to time-based decay in single adaptation task and interferences in multiple adaptation tasks.

Families Among High-Inclination Asteroids

NASA Astrophysics Data System (ADS)

Novakovic, B.; Cellino, A.; Knezevic, Z.

2012-05-01

We review briefly the most important results of the classification of high-inclination asteroids into families performed by Novakovic et al.(Icarus, 2011,216) and present some new results about a very interesting (5438) Lorre cluster.

MSG test report: removal of residual sodium. [LMFBR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harty, R.B.

1974-03-08

This report presents the results of cleaning activities performed to remove residual sodium from the AI Modular Steam Generator. A description of the cleaning loop, cleaning procedure, results, and visual inspection are included.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooke, Gary A.; Pestovich, John A.; Huber, Heinz J.

This report presents the results for solid phase characterization (SPC) of solid samples removed from tank 241-C-108 (C-108) on August 12-13,2012, using the off-riser sampler. Samples were received at the 222-S Laboratory on August 13 and were described and photographed. The SPC analyses that were performed include scanning electron microscopy (SEM) using the ASPEX(R)l scanning electron microscope, X-ray diffraction (XRD) using the Rigaku(R) 2 MiniFlex X-ray diffractometer, and polarized light microscopy (PLM) using the Nikon(R) 3 Eclipse Pol optical microscope. The SEM is equipped with an energy dispersive X-ray spectrometer (EDS) to provide chemical information. Gary A. Cooke conducted themore » SEM analysis, John A. Pestovich performed the XRD analysis, and Dr. Heinz J. Huber performed the PLM examination. The results of these analyses are presented here.« less

Dynamic and Transient Performance of Turbofan/Turboshaft Convertible Engine With Variable Inlet Guide Vanes

NASA Technical Reports Server (NTRS)

McArdle, Jack G.; Barth, Richard L.; Wenzel, Leon M.; Biesiadny, Thomas J.

1996-01-01

A convertible engine called the CEST TF34, using the variable inlet guide vane method of power change, was tested on an outdoor stand at the NASA Lewis Research Center with a waterbrake dynamometer for the shaft load. A new digital electronic system, in conjunction with a modified standard TF34 hydromechanical fuel control, kept engine operation stable and safely within limits. All planned testing was completed successfully. Steady-state performance and acoustic characteristics were reported previously and are referenced. This report presents results of transient and dynamic tests. The transient tests measured engine response to several rapid changes in thrust and torque commands at constant fan (shaft) speed. Limited results from dynamic tests using the pseudorandom binary noise technique are also presented. Performance of the waterbrake dynamometer is discussed in an appendix.

Discriminating between first- and second-order cognition in first-episode paranoid schizophrenia.

PubMed

Bliksted, Vibeke; Samuelsen, Erla; Sandberg, Kristian; Bibby, Bo Martin; Overgaard, Morten Storm

2017-03-01

An impairment of visually perceiving backward masked stimuli is commonly observed in patients with schizophrenia, yet it is unclear whether this impairment is the result of a deficiency in first or higher order processing and for which subtypes of schizophrenia it is present. Here, we compare identification (first order) and metacognitive (higher order) performance in a visual masking paradigm between a highly homogenous group of young first-episode patients diagnosed with paranoid schizophrenia (N = 11) to that of carefully matched healthy controls (N = 13). We find no difference across groups in first-order performance, but find a difference in metacognitive performance, particularly for stimuli with relatively high visibility. These results indicate that the masking deficit is present in first-episode patients with paranoid schizophrenia, but that it is primarily an impairment of metacognition.

Hydrogen-oxygen catalytic ignition and thruster investigation. Volume 1: Catalytic ignition and low pressure thruster evaluations

NASA Technical Reports Server (NTRS)

Johnson, R. J.

1972-01-01

An experimental and analytical program was conducted to evaluate catalytic igniter operational limits, igniter scaling criteria, and delivered performance of cooled, flightweight gaseous hydrogen-oxygen reaction control thrusters. Specific goals were to: (1) establish operating life and environmental effects for both Shell 405-ABSG and Engelhard MFSA catalysts, (2) provide generalized igniter design guidelines for high response without flashback, and (3) to determine overall performance of thrusters at chamber pressures of 15 and 300 psia (103 and 2068 kN/sq m) and thrust levels of 30 and 1500 lbf, respectively. The experimental results have demonstrated the feasibility of reliable, high response catalytic ignition and the effectiveness of ducted chamber cooling for a high performance flightweight thruster. This volume presents the results of the catalytic igniter and low pressure thruster evaluations are presented.

Conceptual Design and Performance Analysis for a Large Civil Compound Helicopter

NASA Technical Reports Server (NTRS)

Russell, Carl; Johnson, Wayne

2012-01-01

A conceptual design study of a large civil compound helicopter is presented. The objective is to determine how a compound helicopter performs when compared to both a conventional helicopter and a tiltrotor using a design mission that is shorter than optimal for a tiltrotor and longer than optimal for a helicopter. The designs are generated and analyzed using conceptual design software and are further evaluated with a comprehensive rotorcraft analysis code. Multiple metrics are used to determine the suitability of each design for the given mission. Plots of various trade studies and parameter sweeps as well as comprehensive analysis results are presented. The results suggest that the compound helicopter examined for this study would not be competitive with a tiltrotor or conventional helicopter, but multiple possibilities are identified for improving the performance of the compound helicopter in future research.

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.

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.

Flight experience with flight control redundancy management

NASA Technical Reports Server (NTRS)

Szalai, K. J.; Larson, R. R.; Glover, R. D.

1980-01-01

Flight experience with both current and advanced redundancy management schemes was gained in recent flight research programs using the F-8 digital fly by wire aircraft. The flight performance of fault detection, isolation, and reconfiguration (FDIR) methods for sensors, computers, and actuators is reviewed. Results of induced failures as well as of actual random failures are discussed. Deficiencies in modeling and implementation techniques are also discussed. The paper also presents comparison off multisensor tracking in smooth air, in turbulence, during large maneuvers, and during maneuvers typical of those of large commercial transport aircraft. The results of flight tests of an advanced analytic redundancy management algorithm are compared with the performance of a contemporary algorithm in terms of time to detection, false alarms, and missed alarms. The performance of computer redundancy management in both iron bird and flight tests is also presented.

Computational Analysis of a Prototype Martian Rotorcraft Experiment

NASA Technical Reports Server (NTRS)

Corfeld, Kelly J.; Strawn, Roger C.; Long, Lyle N.

2002-01-01

This paper presents Reynolds-averaged Navier-Stokes calculations for a prototype Martian rotorcraft. The computations are intended for comparison with an ongoing Mars rotor hover test at NASA Ames Research Center. These computational simulations present a new and challenging problem, since rotors that operate on Mars will experience a unique low Reynolds number and high Mach number environment. Computed results for the 3-D rotor differ substantially from 2-D sectional computations in that the 3-D results exhibit a stall delay phenomenon caused by rotational forces along the blade span. Computational results have yet to be compared to experimental data, but computed performance predictions match the experimental design goals fairly well. In addition, the computed results provide a high level of detail in the rotor wake and blade surface aerodynamics. These details provide an important supplement to the expected experimental performance data.

Mathematical literacy in Plant Physiology undergraduates: results of interventions aimed at improving students' performance

NASA Astrophysics Data System (ADS)

Vila, Francisca; Sanz, Amparo

2013-09-01

The importance of mathematical literacy in any scientific career is widely recognized. However, various studies report lack of numeracy and mathematical literacy in students from various countries. In the present work, we present a detailed study of the mathematical literacy of Spanish undergraduate students of Biology enrolled in a Plant Physiology course. We have performed individual analyses of results obtained during the period 2000-2011, for questions in the examinations requiring and not requiring mathematical skills. Additionally, we present the outcome of two interventions introduced with the aim of helping students improve their prospects for success in the course. Our results confirm previous research showing students' deficiencies in mathematical skills. However, the scores obtained for mathematical questions in the examinations are good predictors of the final grades attained in Plant Physiology, as there are strong correlations at the individual level between results for questions requiring and not requiring mathematical skills. The introduction of a laboratory session devoted to strengthening the application of students' previously acquired mathematical knowledge did not change significantly the results obtained for mathematical questions. Since mathematical abilities of students entering university have declined in recent years, this intervention may have helped to maintain students' performance to a level comparable to that of previous years. The outcome of self-assessment online tests indicates that although Mathematics anxiety is lower than during examinations, the poor results obtained for questions requiring mathematical skills are, at least in part, due to a lack of self-efficacy.

A Survey of the Capacity of Selected Urban School Districts to Utilize and Disseminate Innovations in Educational Technology.

ERIC Educational Resources Information Center

Adams, Isaac, Jr.

This report presents the results of an informal survey which focused upon the manner in which urban school systems are organized to perform the functions of utilization and dissemination of educational innovations. The systems of each of twenty-eight urban districts surveyed are briefly described. Results presented indicate that (1) all…

From Red Tape to Results: Creating a Government That Works Better & Costs Less. Report of the National Performance Review.

ERIC Educational Resources Information Center

Gore, Al

This monograph presents results of a 6-month study of the federal government and the Clinton Administration's proposal for a decade-long process of re-inventing the federal government's operations. Each of four major principles are presented in a chapter organized around specific steps towards its implementation. These principles are: cutting red…

The hard fall effect: high working memory capacity leads to a higher, but less robust short-term memory performance.

PubMed

Thomassin, Noémylle; Gonthier, Corentin; Guerraz, Michel; Roulin, Jean-Luc

2015-01-01

Participants with a high working memory span tend to perform better than low spans in a variety of tasks. However, their performance is paradoxically more impaired when they have to perform two tasks at once, a phenomenon that could be labeled the "hard fall effect." The present study tested whether this effect exists in a short-term memory task, and investigated the proposal that the effect is due to high spans using efficient facilitative strategies under simple task conditions. Ninety-eight participants performed a spatial short-term memory task under simple and dual task conditions; stimuli presentation times either allowed for the use of complex facilitative strategies or not. High spans outperformed low spans only under simple task conditions when presentation times allowed for the use of facilitative strategies. These results indicate that the hard fall effect exists on a short-term memory task and may be caused by individual differences in strategy use.

Feasibility of introducing ferromagnetic materials to onboard bulk high-Tc superconductors to enhance the performance of present maglev systems

NASA Astrophysics Data System (ADS)

Deng, Zigang; Wang, Jiasu; Zheng, Jun; Zhang, Ya; Wang, Suyu

2013-02-01

Performance improvement is a long-term research task for the promotion of practical application of promising high-temperature superconducting (HTS) magnetic levitation (maglev) vehicle technologies. We studied the feasibility to enhance the performance of present HTS Maglev systems by introducing ferromagnetic materials to onboard bulk superconductors. The principle here is to make use of the high magnetic permeability of ferromagnetic materials to alter the flux distribution of the permanent magnet guideway for the enhancement of magnetic field density at the position of the bulk superconductors. Ferromagnetic iron plates were added to the upper surface of bulk superconductors and their geometric and positioning effects on the maglev performance were investigated experimentally. Results show that the guidance performance (stability) was enhanced greatly for a particular setup when compared to the present maglev system which is helpful in the application where large guidance forces are needed such as maglev tracks with high degrees of curves.

Attention in a multi-task environment

NASA Technical Reports Server (NTRS)

Andre, Anthony D.; Heers, Susan T.

1993-01-01

Two experiments used a low fidelity multi-task simulation to investigate the effects of cue specificity on task preparation and performance. Subjects performed a continuous compensatory tracking task and were periodically prompted to perform one of several concurrent secondary tasks. The results provide strong evidence that subjects enacted a strategy to actively divert resources towards secondary task preparation only when they had specific information about an upcoming task to be performed. However, this strategy was not as much affected by the type of task cued (Experiment 1) or its difficulty level (Experiment 2). Overall, subjects seemed aware of both the costs (degraded primary task tracking) and benefits (improved secondary task performance) of cue information. Implications of the present results for computational human performance/workload models are discussed.

Meshless Lagrangian SPH method applied to isothermal lid-driven cavity flow at low-Re numbers

NASA Astrophysics Data System (ADS)

Fraga Filho, C. A. D.; Chacaltana, J. T. A.; Pinto, W. J. N.

2018-01-01

SPH is a recent particle method applied in the cavities study, without many results available in the literature. The lid-driven cavity flow is a classic problem of the fluid mechanics, extensively explored in the literature and presenting a considerable complexity. The aim of this paper is to present a solution from the Lagrangian viewpoint for this problem. The discretization of the continuum domain is performed using the Lagrangian particles. The physical laws of mass, momentum and energy conservation are presented by the Navier-Stokes equations. A serial numerical code, written in Fortran programming language, has been used to perform the numerical simulations. The application of the SPH and comparison with the literature (mesh methods and a meshless collocation method) have been done. The positions of the primary vortex centre and the non-dimensional velocity profiles passing through the geometric centre of the cavity have been analysed. The numerical Lagrangian results showed a good agreement when compared to the results found in the literature, specifically for { Re} < 100.00 . Suggestions for improvements in the SPH model presented are listed, in the search for better results for flows with higher Reynolds numbers.

Mariner 9 data storage subsystem flight performance summary

NASA Technical Reports Server (NTRS)

Thomas, N. E.; Larman, B. T.

1973-01-01

The performance is summarized of the Mariner 9 Data Storage Subsystem (DSS) throughout the primary and extended missions. Information presented is limited to reporting of anomalies which occurred during the playback sequences. Tables and figures describe the anomalies (dropouts, missing and added bits, in the imaging data) as a function of time (accumulated tape passes). The data results indicate that the performance of the DSS was satisfactory and within specification throughout the mission. The data presented is taken from the Spacecraft Team Incident/Surprise Anomaly Log recorded during the mission. Pertinent statistics concerning the tape transport performance are given. Also presented is a brief description of DSS operation, particularly that related to the recorded anomalies. This covers the video data encoding and how it is interpreted/decoded by ground data processing and the functional operation of the DSS in abnormal conditions such as loss of lock to the playback signal.

Impact of Aerodynamics and Structures Technology on Heavy Lift Tiltrotors

NASA Technical Reports Server (NTRS)

Acree, C. W., Jr.

2006-01-01

Rotor performance and aeroelastic stability are presented for a 124,000-lb Large Civil Tilt Rotor (LCTR) design. It was designed to carry 120 passengers for 1200 nm, with performance of 350 knots at 30,000 ft altitude. Design features include a low-mounted wing and hingeless rotors, with a very low cruise tip speed of 350 ft/sec. The rotor and wing design processes are described, including rotor optimization methods and wing/rotor aeroelastic stability analyses. New rotor airfoils were designed specifically for the LCTR; the resulting performance improvements are compared to current technology airfoils. Twist, taper and precone optimization are presented, along with the effects of blade flexibility on performance. A new wing airfoil was designed and a composite structure was developed to meet the wing load requirements for certification. Predictions of aeroelastic stability are presented for the optimized rotor and wing, along with summaries of the effects of rotor design parameters on stability.

Structural equation model analysis for the evaluation of overall driving performance: A driving simulator study focusing on driver distraction.

PubMed

Papantoniou, Panagiotis

2018-04-03

The present research relies on 2 main objectives. The first is to investigate whether latent model analysis through a structural equation model can be implemented on driving simulator data in order to define an unobserved driving performance variable. Subsequently, the second objective is to investigate and quantify the effect of several risk factors including distraction sources, driver characteristics, and road and traffic environment on the overall driving performance and not in independent driving performance measures. For the scope of the present research, 95 participants from all age groups were asked to drive under different types of distraction (conversation with passenger, cell phone use) in urban and rural road environments with low and high traffic volume in a driving simulator experiment. Then, in the framework of the statistical analysis, a correlation table is presented investigating any of a broad class of statistical relationships between driving simulator measures and a structural equation model is developed in which overall driving performance is estimated as a latent variable based on several individual driving simulator measures. Results confirm the suitability of the structural equation model and indicate that the selection of the specific performance measures that define overall performance should be guided by a rule of representativeness between the selected variables. Moreover, results indicate that conversation with the passenger was not found to have a statistically significant effect, indicating that drivers do not change their performance while conversing with a passenger compared to undistracted driving. On the other hand, results support the hypothesis that cell phone use has a negative effect on driving performance. Furthermore, regarding driver characteristics, age, gender, and experience all have a significant effect on driving performance, indicating that driver-related characteristics play the most crucial role in overall driving performance. The findings of this study allow a new approach to the investigation of driving behavior in driving simulator experiments and in general. By the successful implementation of the structural equation model, driving behavior can be assessed in terms of overall performance and not through individual performance measures, which allows an important scientific step forward from piecemeal analyses to a sound combined analysis of the interrelationship between several risk factors and overall driving performance.

Using coal inside California for electric power

NASA Technical Reports Server (NTRS)

Moore, J. B.

1978-01-01

In a detailed analysis performed at Southern California Edison on a wide variety of technologies, the direct combustion of coal and medium BTU gas from coal were ranked just below nuclear power for future nonpetroleum based electric power generation. As a result, engineering studies were performed for demonstration projects for the direct combustion of coal and medium BTU gas from coal. Graphs are presented for power demand, and power cost. Direct coal combustion and coal gasification processes are presented.

Thermocouples of tantalum and rhenium alloys for more stable vacuum-high temperature performance

NASA Technical Reports Server (NTRS)

Morris, J. F. (Inventor)

1977-01-01

Thermocouples of the present invention provide stability and performance reliability in systems involving high temperatures and vacuums by employing a bimetallic thermocouple sensor wherein each metal of the sensor is selected from a group of metals comprising tantalum and rhenium and alloys containing only those two metals. The tantalum, rhenium thermocouple sensor alloys provide bare metal thermocouple sensors having advantageous vapor pressure compatibilities and performance characteristics. The compatibility and physical characteristics of the thermocouple sensor alloys of the present invention result in improved emf, temperature properties and thermocouple hot junction performance. The thermocouples formed of the tantalum, rhenium alloys exhibit reliability and performance stability in systems involving high temperatures and vacuums and are adaptable to space propulsion and power systems and nuclear environments.

Geometry optimization for micro-pressure sensor considering dynamic interference

NASA Astrophysics Data System (ADS)

Yu, Zhongliang; Zhao, Yulong; Li, Lili; Tian, Bian; Li, Cun

2014-09-01

Presented is the geometry optimization for piezoresistive absolute micro-pressure sensor. A figure of merit called the performance factor (PF) is defined as a quantitative index to describe the comprehensive performances of a sensor including sensitivity, resonant frequency, and acceleration interference. Three geometries are proposed through introducing islands and sensitive beams into typical flat diaphragm. The stress distributions of sensitive elements are analyzed by finite element method. Multivariate fittings based on ANSYS simulation results are performed to establish the equations about surface stress, deflection, and resonant frequency. Optimization by MATLAB is carried out to determine the dimensions of the geometries. Convex corner undercutting is evaluated. Each PF of the three geometries with the determined dimensions is calculated and compared. Silicon bulk micromachining is utilized to fabricate the prototypes of the sensors. The outputs of the sensors under both static and dynamic conditions are tested. Experimental results demonstrate the rationality of the defined performance factor and reveal that the geometry with quad islands presents the highest PF of 210.947 Hz1/4. The favorable overall performances enable the sensor more suitable for altimetry.

In-Flight Guidance, Navigation, and Control Performance Results for the GOES-16 Spacecraft

NASA Technical Reports Server (NTRS)

Chapel, Jim; Stancliffe, Devin; Bevacqua, Tim; Winkler, Stephen; Clapp, Brian; Rood, Tim; Freesland, Doug; Reth, Alan; Early, Derrick; Walsh, Tim;

The effect of visual representation style in problem-solving: a perspective from cognitive processes.

PubMed

Nyamsuren, Enkhbold; Taatgen, Niels A

2013-01-01

Using results from a controlled experiment and simulations based on cognitive models, we show that visual presentation style can have a significant impact on performance in a complex problem-solving task. We compared subject performances in two isomorphic, but visually different, tasks based on a card game of SET. Although subjects used the same strategy in both tasks, the difference in presentation style resulted in radically different reaction times and significant deviations in scanpath patterns in the two tasks. Results from our study indicate that low-level subconscious visual processes, such as differential acuity in peripheral vision and low-level iconic memory, can have indirect, but significant effects on decision making during a problem-solving task. We have developed two ACT-R models that employ the same basic strategy but deal with different presentations styles. Our ACT-R models confirm that changes in low-level visual processes triggered by changes in presentation style can propagate to higher-level cognitive processes. Such a domino effect can significantly affect reaction times and eye movements, without affecting the overall strategy of problem solving.

The Effect of Visual Representation Style in Problem-Solving: A Perspective from Cognitive Processes

PubMed Central

Nyamsuren, Enkhbold; Taatgen, Niels A.

2013-01-01

Using results from a controlled experiment and simulations based on cognitive models, we show that visual presentation style can have a significant impact on performance in a complex problem-solving task. We compared subject performances in two isomorphic, but visually different, tasks based on a card game of SET. Although subjects used the same strategy in both tasks, the difference in presentation style resulted in radically different reaction times and significant deviations in scanpath patterns in the two tasks. Results from our study indicate that low-level subconscious visual processes, such as differential acuity in peripheral vision and low-level iconic memory, can have indirect, but significant effects on decision making during a problem-solving task. We have developed two ACT-R models that employ the same basic strategy but deal with different presentations styles. Our ACT-R models confirm that changes in low-level visual processes triggered by changes in presentation style can propagate to higher-level cognitive processes. Such a domino effect can significantly affect reaction times and eye movements, without affecting the overall strategy of problem solving. PMID:24260415

Centrifugal slurry pump wear and hydraulic studies. Phase II report. Experimental studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mistry, D.; Cooper, P.; Biswas, C.

1983-01-01

This report describes the work performed by Ingersoll-Rand Research, Inc., under Phase II, Experimental Studies for the contract entitled, Centrifugal Slurry Pump Wear and Hydraulic Studies. This work was carried out for the US Department of Energy under Contract No. DE-AC-82PC50035. The basic development approach pursued this phase is presented, followed by a discussion on wear relationships. The analysis, which resulted in the development of a mathematical wear model relating pump life to some of the key design and operating parameters, is presented. The results, observations, and conclusions of the experimental investigation on small scale pumps that led to themore » selected design features for the prototype pump are discussed. The material investigation was performed at IRRI, ORNL and Battelle. The rationale for selecting the materials for testing, the test methods and apparatus used, and the results obtained are presented followed by a discussion on materials for a prototype pump. In addition, the prototype pump test facility description, as well as the related design and equipment details, are presented. 20 references, 53 figures, 13 tables.« less

Melodic contour identification by cochlear implant listeners.

PubMed

Galvin, John J; Fu, Qian-Jie; Nogaki, Geraldine

2007-06-01

While the cochlear implant provides many deaf patients with good speech understanding in quiet, music perception and appreciation with the cochlear implant remains a major challenge for most cochlear implant users. The present study investigated whether a closed-set melodic contour identification (MCI) task could be used to quantify cochlear implant users' ability to recognize musical melodies and whether MCI performance could be improved with moderate auditory training. The present study also compared MCI performance with familiar melody identification (FMI) performance, with and without MCI training. For the MCI task, test stimuli were melodic contours composed of 5 notes of equal duration whose frequencies corresponded to musical intervals. The interval between successive notes in each contour was varied between 1 and 5 semitones; the "root note" of the contours was also varied (A3, A4, and A5). Nine distinct musical patterns were generated for each interval and root note condition, resulting in a total of 135 musical contours. The identification of these melodic contours was measured in 11 cochlear implant users. FMI was also evaluated in the same subjects; recognition of 12 familiar melodies was tested with and without rhythm cues. MCI was also trained in 6 subjects, using custom software and melodic contours presented in a different frequency range from that used for testing. Results showed that MCI recognition performance was highly variable among cochlear implant users, ranging from 14% to 91% correct. For most subjects, MCI performance improved as the number of semitones between successive notes was increased; performance was slightly lower for the A3 root note condition. Mean FMI performance was 58% correct when rhythm cues were preserved and 29% correct when rhythm cues were removed. Statistical analyses revealed no significant correlation between MCI performance and FMI performance (with or without rhythmic cues). However, MCI performance was significantly correlated with vowel recognition performance; FMI performance was not correlated with cochlear implant subjects' phoneme recognition performance. Preliminary results also showed that the MCI training improved all subjects' MCI performance; the improved MCI performance also generalized to improved FMI performance. Preliminary data indicate that the closed-set MCI task is a viable approach toward quantifying an important component of cochlear implant users' music perception. The improvement in MCI performance and generalization to FMI performance with training suggests that MCI training may be useful for improving cochlear implant users' music perception and appreciation; such training may be necessary to properly evaluate patient performance, as acute measures may underestimate the amount of musical information transmitted by the cochlear implant device and received by cochlear implant listeners.

On the self-serving function of an academic wooden leg: test anxiety as a self-handicapping strategy.

PubMed

Smith, C W; Snyder, D R; Handelsman, M M

1982-02-01

The present study investigated the hypothesis that psychological symptoms may serve a self-protective function by providing an alternative explanation for potential failure in evaluating situations. It was hypothesized that highly test-anxious subjects would report anxiety symptoms in a pattern that reflected strategic presentation of symptoms; more specifically, it was predicted that greater reported anxiety should result when anxiety was a viable explanation for poor performance on an intelligence test and that lower reported anxiety should result when anxiety was not a viable explanation for poor performance. Analysis of state measures of self-reported anxiety supported these predictions. Further analysis indicated that when anxiety was not a viable explanation for poor test performance, high test-anxiety subjects reported reduced effort as an alternative self-protective strategy. These results are discussed in terms of traditional models of symptoms as self-protective strategies, current social psychological models of symptoms, and in reference to recent theory and research about the nature and treatment of test anxiety.

Underwater Mapping Results for Seabotix vLBV300 Vehicle with Tritech Gemini 720i Imaging Sonar near Newport, OR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hollinger, Geoffrey

This document presents results from tests to demonstrate underwater mapping capabilities of an underwater vehicle in conditions typically found in marine renewable energy arrays. These tests were performed with a tethered Seabotix vLBV300 underwater vehicle. The vehicle is equipped with an inertial navigation system (INS) based on a Gladiator Landmark 40 IMU and Teledyne Explorer Doppler Velocity Log, as well as a Gemini 720i scanning sonar acquired from Tritech. The results presented include both indoor pool and offshore deployments. The indoor pool deployments were performed on October 7, 2016 and February 3, 2017 in Corvallis, OR. The offshore deployment wasmore » performed on April 20, 2016 off the coast of Newport, OR (44.678 degrees N, 124.109 degrees W). During the mission period, the sea state varied between 3 and 4, with an average significant wave height of 1.6 m. Data was recorded from both the INS and the sonar.« less

Trajectory-based heating analysis for the European Space Agency/Rosetta Earth Return Vehicle

NASA Technical Reports Server (NTRS)

Henline, William D.; Tauber, Michael E.

1994-01-01

A coupled, trajectory-based flowfield and material thermal-response analysis is presented for the European Space Agency proposed Rosetta comet nucleus sample return vehicle. The probe returns to earth along a hyperbolic trajectory with an entry velocity of 16.5 km/s and requires an ablative heat shield on the forebody. Combined radiative and convective ablating flowfield analyses were performed for the significant heating portion of the shallow ballistic entry trajectory. Both quasisteady ablation and fully transient analyses were performed for a heat shield composed of carbon-phenolic ablative material. Quasisteady analysis was performed using the two-dimensional axisymmetric codes RASLE and BLIMPK. Transient computational results were obtained from the one-dimensional ablation/conduction code CMA. Results are presented for heating, temperature, and ablation rate distributions over the probe forebody for various trajectory points. Comparison of transient and quasisteady results indicates that, for the heating pulse encountered by this probe, the quasisteady approach is conservative from the standpoint of predicted surface recession.

Simulation of floor heating in a combined solar-biomass system integrated in a public bathhouse located in Marrakech

NASA Astrophysics Data System (ADS)

Krarouch, M.; Hamdi, H.; Lamghari, S.; Outzourhit, A.

2018-05-01

This study was conducted in the framework of the HYBRID-BATH project aiming at improving the energy efficiency of traditional Hammams (Turkish baths) and the reduction of the use of wood energy and therefore of greenhouse gases emissions. The present work focuses on the energetic performance of a two-room Hammam located in Marrakech. The rooms were heated by the ground using a hybrid system Micro-CSP/biomass boiler. The dynamic simulation of the system (Hammam coupled with the hybrid system Micro-CSP/biomass boiler) was conducted using TRNSYS18 software. The parametric study was performed on a Typical Meteorological Year data (TMY). This study is devoted to presenting the results of the dynamic simulation of a part of the Hammam investigated, in order to optimize the underfloor heating system. The models and the results of the simulations will be validated by comparisons with experimental results. The main objective is to optimize the operation of such system and to improve its performance.

Jet noise suppressor nozzle development for augmentor wing jet STOL research aircraft (C-8A Buffalo)

NASA Technical Reports Server (NTRS)

Harkonen, D. L.; Marks, C. C.; Okeefe, J. V.

1974-01-01

Noise and performance test results are presented for a full-scale advanced design rectangular array lobe jet suppressor nozzle (plain wall and corrugated). Flight design and installation considerations are also discussed. Noise data are presented in terms of peak PNLT (perceived noise level, tone corrected) suppression relative to the existing airplane and one-third octave-band spectra. Nozzle performance is presented in terms of velocity coefficient. Estimates of the hot thrust available during emergency (engine out) with the suppressor nozzle installed are compared with the current thrust levels produced by the round convergent nozzles.

The 727 airplane target thrust reverser static performance model test for refanned JT8D engines

NASA Technical Reports Server (NTRS)

Chow, C. T. P.; Atkey, E. N.

1974-01-01

The results of a scale model static performance test of target thrust reverser configurations for the Pratt and Whitney Aircraft JT8D-100 series engine are presented. The objective of the test was to select a series of suitable candidate reverser configurations for the subsequent airplane model wind tunnel ingestion and flight controls tests. Test results indicate that adequate reverse thrust performance with compatible engine airflow match is achievable for the selected configurations. Tapering of the lips results in loss of performance and only minimal flow directivity. Door pressure surveys were conducted on a selected number of lip and fence configurations to obtain data to support the design of the thrust reverser system.

Flight Test Results from the NF-15B Intelligent Flight Control System (IFCS) Project with Adaptation to a Simulated Stabilator Failure

NASA Technical Reports Server (NTRS)

Bosworth, John T.; Williams-Hayes, Peggy S.

2007-01-01

Adaptive flight control systems have the potential to be more resilient to extreme changes in airplane behavior. Extreme changes could be a result of a system failure or of damage to the airplane. A direct adaptive neural-network-based flight control system was developed for the National Aeronautics and Space Administration NF-15B Intelligent Flight Control System airplane and subjected to an inflight simulation of a failed (frozen) (unmovable) stabilator. Formation flight handling qualities evaluations were performed with and without neural network adaptation. The results of these flight tests are presented. Comparison with simulation predictions and analysis of the performance of the adaptation system are discussed. The performance of the adaptation system is assessed in terms of its ability to decouple the roll and pitch response and reestablish good onboard model tracking. Flight evaluation with the simulated stabilator failure and adaptation engaged showed that there was generally improvement in the pitch response; however, a tendency for roll pilot-induced oscillation was experienced. A detailed discussion of the cause of the mixed results is presented.

Flight Test Results from the NF-15B Intelligent Flight Control System (IFCS) Project with Adaptation to a Simulated Stabilator Failure

NASA Technical Reports Server (NTRS)

Bosworth, John T.; Williams-Hayes, Peggy S.

2010-01-01

Adaptive flight control systems have the potential to be more resilient to extreme changes in airplane behavior. Extreme changes could be a result of a system failure or of damage to the airplane. A direct adaptive neural-network-based flight control system was developed for the National Aeronautics and Space Administration NF-15B Intelligent Flight Control System airplane and subjected to an inflight simulation of a failed (frozen) (unmovable) stabilator. Formation flight handling qualities evaluations were performed with and without neural network adaptation. The results of these flight tests are presented. Comparison with simulation predictions and analysis of the performance of the adaptation system are discussed. The performance of the adaptation system is assessed in terms of its ability to decouple the roll and pitch response and reestablish good onboard model tracking. Flight evaluation with the simulated stabilator failure and adaptation engaged showed that there was generally improvement in the pitch response; however, a tendency for roll pilot-induced oscillation was experienced. A detailed discussion of the cause of the mixed results is presented.

Experience with HEP analysis on mounted filesystems.

NASA Astrophysics Data System (ADS)

Fuhrmann, Patrick; Gasthuber, Martin; Kemp, Yves; Ozerov, Dmitry

2012-12-01

We present results on different approaches on mounted filesystems in use or under investigation at DESY. dCache, established since long as a storage system for physics data has implemented the NFS v4.1/pNFS protocol. New performance results will be shown with the most current version of the dCache server. In addition to the native usage of the mounted filesystem in a LAN environment, the results are given for the performance of the dCache NFS v4.1/pNFS in WAN case. Several commercial vendors are currently in alpha or beta phase of adding the NFS v4.1/pNFS protocol to their storage appliances. We will test some of these vendor solutions for their readiness for HEP analysis. DESY has recently purchased an IBM Sonas system. We will present the result of a thorough performance evaluation using the native protocols NFS (v3 or v4) and GPFS. As the emphasis is on the usability for end user analysis, we will use latest ROOT versions and current end user analysis code for benchmark scenarios.

Education Criteria for Performance Excellence, 2002.

ERIC Educational Resources Information Center

National Inst. of Standards and Technology, Gaithersburg, MD.

The education criteria presented in this guide are designed to help organizations use an integrated approach to organizational performance management that results in delivery of ever-improving value to students and stakeholders. Implementation of the criteria will contribute to improvement of education quality, improvement of overall…

Predicting School Performance with the Early Screening Inventory.

ERIC Educational Resources Information Center

Meisels, Samuel J.; And Others

1984-01-01

Proposes criteria for defining and selecting preschool developmental screening instruments and describes the Early Screening Inventory (ESI), a developmental screening instrument designed to satisfy these criteria. Presents results of several studies demonstrating that the ESI predicts school performance with moderate to excellent accuracy through…

Integrated vehicle-based safety systems heavy-truck on-road test report

DOT National Transportation Integrated Search

2008-08-01

This report presents results from a series of on-road verification tests performed to determine the readiness of a prototype : integrated warning system to advance to field testing, as well as to identify areas of system performance that should be im...

Integrated vehicle-based safety systems light-vehicle on-road test report

DOT National Transportation Integrated Search

2008-08-01

This report presents results from a series of on-road verification tests performed to determine the readiness of a prototype : integrated warning system to advance to field testing, as well as to identify areas of system performance that should be im...

Integrating Human Factors into Space Vehicle Processing for Risk Management

NASA Technical Reports Server (NTRS)

Woodbury, Sarah; Richards, Kimberly J.

2008-01-01

This presentation will discuss the multiple projects performed in United Space Alliance's Human Engineering Modeling and Performance (HEMAP) Lab, improvements that resulted from analysis, and the future applications of the HEMAP Lab for risk assessment by evaluating human/machine interaction and ergonomic designs.

Look at me, I'm happy and creative: The effect of impression management on behavior in social presence.

PubMed

Uziel, Liad

2010-12-01

The present research tested competing approaches to individual differences in impression management (as measured with social desirability scales) and their implication for behavior in social contexts. A defensiveness approach argues that impression management is a source of defensive self-presentation, which causes performance impairment in public social settings. The competing adjustment approach argues that impression management measures friendliness and self-control, which should bring about performance facilitation in public social settings. To decide between these approaches, two experiments utilized a social facilitation paradigm, whereby task performance was compared between an alone and a public condition. The results supported the predictions of the adjustment approach. Across different tasks, a high impression management score was associated with performance facilitation in social presence, expressed in greater creativity, positive implicit affect, and high self-control. The results reveal previously unnoticed constructive effects of impression management, supporting the reframing of the trait as reflecting interpersonally oriented self-control.

Performance of silvered Teflon thermal control blankets on spacecraft

NASA Astrophysics Data System (ADS)

Pippin, G.; Stuckey, W. K.; Hemminger, C. S.

1993-03-01

Silver-backed fluorinated ethylene propylene Teflon (Ag/FEP) thin film material was used for thermal control in many locations on the Long Duration Exposure Facility (LDEF). The Ag/FEP registered the effects of atomic oxygen, solar ultraviolet radiation, meteoroid and debris impacts, thermal cycling, and contamination. This report summarizes the post-flight condition of the Ag/FEP, compares the results with performance on other spacecraft, and presents lifetime estimates for use under a variety of environmental exposures. Measurements of optical property and mechanical property and surface chemistry changes with exposure conditions, and their significance for design considerations and expected performance lifetimes, are reported for material flown on LDEF. The LDEF based data provides detailed information performance of Ag/FEP under relatively long term exposure in low Earth orbit. Comparison of this data with results from short term shuttle flights, Solar Max, SCATHA, other satellites, and ground based measurements is made to present a comprehensive summary of the use of this material for spacecraft applications.

Rise time and response measurements on a LiSOCl2 cell

NASA Technical Reports Server (NTRS)

Bastien, Caroline; Lecomte, Eric J.

1992-01-01

Dynamic impedance tests were performed on a 180 Ah LiSOCl2 cell in the frame of a short term work contract awarded by Aerospatiale as part of the Hermes Space Plane development work. These tests consisted of rise time and response measurements. The rise time test was performed to show the ability to deliver 4 KW, in the nominal voltage range (75-115 V), within less than 100 microseconds, and after a period at rest of 13 days. The response measurements test consisted of step response and frequency response tests. The frequency response test was performed to characterize the response of the LiSOCl2 cell to a positive or negative load step of 10 A starting from various currents. The test was performed for various depths of discharge and various temperatures. The test results were used to build a mathematical, electrical model of the LiSOCl2 cell which are also presented. The test description, test results, electrical modelization description, and conclusions are presented.

Comparison of performance of computer display monitors for radiological diagnosis; "diagnostic" high brightness monochrome LCD, 3MP vs "clinical review" colour LCD, 2MP.

PubMed

Sim, L; Manthey, K; Stuckey, S

2007-06-01

A study to compare performance of the following display monitors for application as PACS CR diagnostic workstations is described. 1. Diagnostic quality, 3 Mega Pixel, 21 inch monochrome LCD monitors--Planar C3i. 2. Clinical review quality, 2 Mega Pixel, 21 inch colour LCD monitors--Planar PX212. Two sets of seventy radiological studies were presented to four senior radiologists on two occasions, using different displays on each occasion. The clinical condition used for this investigation was to query for the presence of a solitary pulmonary nodule. Receiver Operating Characteristic (ROC) curves were constructed for diagnostic performance for each presentation. Areas under the ROC curves (AUC) for diagnosis using different monitors were compared and the following results obtained: Monochrome AUC = 0.813 +/- 0.02, Colour AUC = 0.801 +/- 0.021. These results indicate that there is no statistically significant difference in the performance of these monitor types at a 95% confidence level.

Evaluation of a fault tolerant system for an integrated avionics sensor configuration with TSRV flight data

NASA Technical Reports Server (NTRS)

Caglayan, A. K.; Godiwala, P. M.

1985-01-01

The performance analysis results of a fault inferring nonlinear detection system (FINDS) using sensor flight data for the NASA ATOPS B-737 aircraft in a Microwave Landing System (MLS) environment is presented. First, a statistical analysis of the flight recorded sensor data was made in order to determine the characteristics of sensor inaccuracies. Next, modifications were made to the detection and decision functions in the FINDS algorithm in order to improve false alarm and failure detection performance under real modelling errors present in the flight data. Finally, the failure detection and false alarm performance of the FINDS algorithm were analyzed by injecting bias failures into fourteen sensor outputs over six repetitive runs of the five minute flight data. In general, the detection speed, failure level estimation, and false alarm performance showed a marked improvement over the previously reported simulation runs. In agreement with earlier results, detection speed was faster for filter measurement sensors soon as MLS than for filter input sensors such as flight control accelerometers.

Performance analysis of high-concentrated multi-junction solar cells in hot climate

NASA Astrophysics Data System (ADS)

Ghoneim, Adel A.; Kandil, Kandil M.; Alzanki, Talal H.; Alenezi, Mohammad R.

2018-03-01

Multi-junction concentrator solar cells are a promising technology as they can fulfill the increasing energy demand with renewable sources. Focusing sunlight upon the aperture of multi-junction photovoltaic (PV) cells can generate much greater power densities than conventional PV cells. So, concentrated PV multi-junction solar cells offer a promising way towards achieving minimum cost per kilowatt-hour. However, these cells have many aspects that must be fixed to be feasible for large-scale energy generation. In this work, a model is developed to analyze the impact of various atmospheric factors on concentrator PV performance. A single-diode equivalent circuit model is developed to examine multi-junction cells performance in hot weather conditions, considering the impacts of both temperature and concentration ratio. The impacts of spectral variations of irradiance on annual performance of various high-concentrated photovoltaic (HCPV) panels are examined, adapting spectra simulations using the SMARTS model. Also, the diode shunt resistance neglected in the existing models is considered in the present model. The present results are efficiently validated against measurements from published data to within 2% accuracy. Present predictions show that the single-diode model considering the shunt resistance gives accurate and reliable results. Also, aerosol optical depth (AOD) and air mass are most important atmospheric parameters having a significant impact on HCPV cell performance. In addition, the electrical efficiency (η) is noticed to increase with concentration to a certain concentration degree after which it decreases. Finally, based on the model predictions, let us conclude that the present model could be adapted properly to examine HCPV cells' performance over a broad range of operating conditions.

Comparison of visual and emotional continuous performance test related to sequence of presentation, gender and age.

PubMed

Markovska-Simoska, S; Pop-Jordanova, N

2009-07-01

(Full text is available at http://www.manu.edu.mk/prilozi). Continous Performance Tests (CPTs) form a group of paradigms for the evaluation of attention and, to a lesser degree, the response inhibition (or disinhibition) component of executive control. The object of this study was to compare performance on a CPT using both visual and emotional tasks in 46 normal adult subjects. In particular, it was to examine the effects of the type of task (VCPT or ECPT), sequence of presentation, and gender/age influence on performance as measured errors of omission, errors of commission, reaction time and variation of reaction time. From the results we can assume that there are significantly worse performance parameters for ECPT than VCPT tasks, with a probable explanation of the influence of emotional stimuli on attention and information-processing and no significant effect of order of presentation and gender on performance. Significant differences with more omission errors for older groups were obtained, showing better attention in younger subjects. Key words: VCPT, ECPT, omission errors, commission errors, reaction time, variation of reaction time, normal adults.

Real-Time Evaluation of Breast Self-Examination Using Computer Vision

PubMed Central

Mohammadi, Eman; Dadios, Elmer P.; Gan Lim, Laurence A.; Cabatuan, Melvin K.; Naguib, Raouf N. G.; Avila, Jose Maria C.; Oikonomou, Andreas

2014-01-01

Breast cancer is the most common cancer among women worldwide and breast self-examination (BSE) is considered as the most cost-effective approach for early breast cancer detection. The general objective of this paper is to design and develop a computer vision algorithm to evaluate the BSE performance in real-time. The first stage of the algorithm presents a method for detecting and tracking the nipples in frames while a woman performs BSE; the second stage presents a method for localizing the breast region and blocks of pixels related to palpation of the breast, and the third stage focuses on detecting the palpated blocks in the breast region. The palpated blocks are highlighted at the time of BSE performance. In a correct BSE performance, all blocks must be palpated, checked, and highlighted, respectively. If any abnormality, such as masses, is detected, then this must be reported to a doctor to confirm the presence of this abnormality and proceed to perform other confirmatory tests. The experimental results have shown that the BSE evaluation algorithm presented in this paper provides robust performance. PMID:25435860

Real-time evaluation of breast self-examination using computer vision.

PubMed

Mohammadi, Eman; Dadios, Elmer P; Gan Lim, Laurence A; Cabatuan, Melvin K; Naguib, Raouf N G; Avila, Jose Maria C; Oikonomou, Andreas

2014-01-01

Breast cancer is the most common cancer among women worldwide and breast self-examination (BSE) is considered as the most cost-effective approach for early breast cancer detection. The general objective of this paper is to design and develop a computer vision algorithm to evaluate the BSE performance in real-time. The first stage of the algorithm presents a method for detecting and tracking the nipples in frames while a woman performs BSE; the second stage presents a method for localizing the breast region and blocks of pixels related to palpation of the breast, and the third stage focuses on detecting the palpated blocks in the breast region. The palpated blocks are highlighted at the time of BSE performance. In a correct BSE performance, all blocks must be palpated, checked, and highlighted, respectively. If any abnormality, such as masses, is detected, then this must be reported to a doctor to confirm the presence of this abnormality and proceed to perform other confirmatory tests. The experimental results have shown that the BSE evaluation algorithm presented in this paper provides robust performance.

Modality dependence and intermodal transfer in the Corsi Spatial Sequence Task: Screen vs. Floor.

PubMed

Röser, Andrea; Hardiess, Gregor; Mallot, Hanspeter A

2016-07-01

Four versions of the Corsi Spatial Sequence Task (CSST) were tested in a complete within-subject design, investigating whether participants' performance depends on the modality of task presentation and reproduction that put different demands on spatial processing. Presentation of the sequence (encoding phase) and the reproduction (recall phase) were each carried out either on a computer screen or on the floor of a room, involving actual walking in the recall phase. Combinations of the two different encoding and recall procedures result in the modality conditions Screen-Screen, Screen-Floor, Floor-Screen, and Floor-Floor. Results show the expected decrease in performance with increasing sequence length, which is likely due to processing limitations of working memory. We also found differences in performance between the modality conditions indicating different involvements of spatial working memory processes. Participants performed best in the Screen-Screen modality condition. Floor-Screen and Floor-Floor modality conditions require additional working memory resources for reference frame transformation and spatial updating, respectively; the resulting impairment of the performance was about the same in these two conditions. Finally, the Screen-Floor modality condition requires both types of additional spatial demands and led to the poorest performance. Therefore, we suggest that besides the well-known spatial requirements of CSST, additional working memory resources are demanded in walking CSST supporting processes such as spatial updating, mental rotation, reference frame transformation, and the control of walking itself.

Guidance, Navigation, and Control Performance for the GOES-R Spacecraft

NASA Technical Reports Server (NTRS)

Chapel, Jim; Stancliffe, Devin; Bevacqua, TIm; Winkler, Stephen; Clapp, Brian; Rood, Tim; Gaylor, David; Freesland, Doug; Krimchansky, Alexander

2014-01-01

The Geostationary Operational Environmental Satellite-R Series (GOES-R) is the first of the next generation geostationary weather satellites. The series represents a dramatic increase in Earth observation capabilities, with 4 times the resolution, 5 times the observation rate, and 3 times the number of spectral bands. GOES-R also provides unprecedented availability, with less than 120 minutes per year of lost observation time. This paper presents the Guidance Navigation & Control (GN&C) requirements necessary to realize the ambitious pointing, knowledge, and Image Navigation and Registration (INR) objectives of GOES-R. Because the suite of instruments is sensitive to disturbances over a broad spectral range, a high fidelity simulation of the vehicle has been created with modal content over 500 Hz to assess the pointing stability requirements. Simulation results are presented showing acceleration, shock response spectra (SRS), and line of sight (LOS) responses for various disturbances from 0 Hz to 512 Hz. Simulation results demonstrate excellent performance relative to the pointing and pointing stability requirements, with LOS jitter for the isolated instrument platform of approximately 1 micro-rad. Attitude and attitude rate knowledge are provided directly to the instrument with an accuracy defined by the Integrated Rate Error (IRE) requirements. The data are used internally for motion compensation. The final piece of the INR performance is orbit knowledge, which GOES-R achieves with GPS navigation. Performance results are shown demonstrating compliance with the 50 to 75 m orbit position accuracy requirements. As presented in this paper, the GN&C performance supports the challenging mission objectives of GOES-R.

A simple performance calculation method for LH2/LOX engines with different power cycles

NASA Technical Reports Server (NTRS)

Schmucker, R. H.

1973-01-01

A simple method for the calculation of the specific impulse of an engine with a gas generator cycle is presented. The solution is obtained by a power balance between turbine and pump. Approximate equations for the performance of the combustion products of LH2/LOX are derived. Performance results are compared with solutions of different engine types.

Variability and Variation of L2 Grammar: A Cross-Sectional Analysis of German Learners' Performance on Two Tasks

ERIC Educational Resources Information Center

Abrams, Zsuzsanna; Rott, Susanne

2017-01-01

Research on second language (L2) grammar in task-based language learning has yielded inconsistent results regarding the effects of task-complexity, prompting calls for more nuanced analyses of L2 development and task performance. The present cross-sectional study contributes to this discussion by comparing the performance of 245 learners of German…

Strapdown gyro test program

NASA Technical Reports Server (NTRS)

Irvine, R. B.; Vanalstine, R.

1977-01-01

The power spectral noise characteristic performance of the Teledyne two-degree-of-freedom dry tuned gimbal gyroscope was determined. Tests were conducted using a current configuration SDG-5 gyro in conjunction with test equipment with minor modification. Long term bias stability tests were conducted as well as some first difference performance tests. The gyro, test equipment, and the tests performed are described. Results are presented.

Short-Term Effects of Midseason Coach Turnover on Team Performance in Soccer

ERIC Educational Resources Information Center

Balduck, Anne-Line; Buelens, Marc; Philippaerts, Renaat

2010-01-01

The present study addressed the issue of short-term performance effects of midseason coach turnover in soccer. The goal of this study was to examine this effect on subsequent short-term team performance. The purposes of this study were to (a) examine whether midseason coach turnover improved results in the short term, and (b) examine how team…

Apollo experience report: Battery subsystem

NASA Technical Reports Server (NTRS)

Trout, J. B.

1972-01-01

Experience with the Apollo command service module and lunar module batteries is discussed. Significant hardware development concepts and hardware test results are summarized, and the operational performance of batteries on the Apollo 7 to 13 missions is discussed in terms of performance data, mission constraints, and basic hardware design and capability. Also, the flight performance of the Apollo battery charger is discussed. Inflight data are presented.

Prechamber Compression-Ignition Engine Performance

NASA Technical Reports Server (NTRS)

Moore, Charles S; Collins, John H , Jr

1938-01-01

Single-cylinder compression-ignition engine tests were made to investigate the performance characteristics of prechamber type of cylinder head. Certain fundamental variables influencing engine performance -- clearance distribution, size, shape, and direction of the passage connecting the cylinder and prechamber, shape of prechamber, cylinder clearance, compression ratio, and boosting -- were independently tested. Results of motoring and of power tests, including several typical indicator cards, are presented.

Largo hot water system long range thermal performance test report, addendum

NASA Technical Reports Server (NTRS)

1978-01-01

The test procedure used and the test results obtained during the long range thermal performance tests of the LARGO Solar Hot Water System under natural environmental conditions are presented. Objectives of these tests were to determine the amount of energy collected, the amount of power required for system operation, system efficiency, temperature distribution, and system performance degradation.

A virtual speaker in noisy classroom conditions: supporting or disrupting children's listening comprehension?

PubMed

Nirme, Jens; Haake, Magnus; Lyberg Åhlander, Viveka; Brännström, Jonas; Sahlén, Birgitta

2018-04-05

Seeing a speaker's face facilitates speech recognition, particularly under noisy conditions. Evidence for how it might affect comprehension of the content of the speech is more sparse. We investigated how children's listening comprehension is affected by multi-talker babble noise, with or without presentation of a digitally animated virtual speaker, and whether successful comprehension is related to performance on a test of executive functioning. We performed a mixed-design experiment with 55 (34 female) participants (8- to 9-year-olds), recruited from Swedish elementary schools. The children were presented with four different narratives, each in one of four conditions: audio-only presentation in a quiet setting, audio-only presentation in noisy setting, audio-visual presentation in a quiet setting, and audio-visual presentation in a noisy setting. After each narrative, the children answered questions on the content and rated their perceived listening effort. Finally, they performed a test of executive functioning. We found significantly fewer correct answers to explicit content questions after listening in noise. This negative effect was only mitigated to a marginally significant degree by audio-visual presentation. Strong executive function only predicted more correct answers in quiet settings. Altogether, our results are inconclusive regarding how seeing a virtual speaker affects listening comprehension. We discuss how methodological adjustments, including modifications to our virtual speaker, can be used to discriminate between possible explanations to our results and contribute to understanding the listening conditions children face in a typical classroom.

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.

The influence of target-masker similarity on across-ear interference in dichotic listening

NASA Astrophysics Data System (ADS)

Brungart, Douglas; Simpson, Brian

2004-05-01

In most dichotic listening tasks, the comprehension of a target speech signal presented in one ear is unaffected by the presence of irrelevant speech in the opposite ear. However, recent results have shown that contralaterally presented interfering speech signals do influence performance when a second interfering speech signal is present in the same ear as the target speech. In this experiment, we examined the influence of target-masker similarity on this effect by presenting ipsilateral and contralateral masking phrases spoken by the same talker, a different same-sex talker, or a different-sex talker than the one used to generate the target speech. The results show that contralateral target-masker similarity has the greatest influence on performance when an easily segregated different-sex masker is presented in the target ear, and the least influence when a difficult-to-segregate same-talker masker is presented in the target ear. These results indicate that across-ear interference in dichotic listening is not directly related to the difficulty of the segregation task in the target ear, and suggest that contralateral maskers are least likely to interfere with dichotic speech perception when the same general strategy could be used to segregate the target from the masking voices in the ipsilateral and contralateral ears.

Effect of a combination of flip and zooming stimuli on the performance of a visual brain-computer interface for spelling.

PubMed

Cheng, Jiao; Jin, Jing; Daly, Ian; Zhang, Yu; Wang, Bei; Wang, Xingyu; Cichocki, Andrzej

2018-02-13

Brain-computer interface (BCI) systems can allow their users to communicate with the external world by recognizing intention directly from their brain activity without the assistance of the peripheral motor nervous system. The P300-speller is one of the most widely used visual BCI applications. In previous studies, a flip stimulus (rotating the background area of the character) that was based on apparent motion, suffered from less refractory effects. However, its performance was not improved significantly. In addition, a presentation paradigm that used a "zooming" action (changing the size of the symbol) has been shown to evoke relatively higher P300 amplitudes and obtain a better BCI performance. To extend this method of stimuli presentation within a BCI and, consequently, to improve BCI performance, we present a new paradigm combining both the flip stimulus with a zooming action. This new presentation modality allowed BCI users to focus their attention more easily. We investigated whether such an action could combine the advantages of both types of stimuli presentation to bring a significant improvement in performance compared to the conventional flip stimulus. The experimental results showed that the proposed paradigm could obtain significantly higher classification accuracies and bit rates than the conventional flip paradigm (p<0.01).

Thermal Model Predictions of Advanced Stirling Radioisotope Generator Performance

NASA Technical Reports Server (NTRS)

Wang, Xiao-Yen J.; Fabanich, William Anthony; Schmitz, Paul C.

2014-01-01

This paper presents recent thermal model results of the Advanced Stirling Radioisotope Generator (ASRG). The three-dimensional (3D) ASRG thermal power model was built using the Thermal Desktop(trademark) thermal analyzer. The model was correlated with ASRG engineering unit test data and ASRG flight unit predictions from Lockheed Martin's (LM's) I-deas(trademark) TMG thermal model. The auxiliary cooling system (ACS) of the ASRG is also included in the ASRG thermal model. The ACS is designed to remove waste heat from the ASRG so that it can be used to heat spacecraft components. The performance of the ACS is reported under nominal conditions and during a Venus flyby scenario. The results for the nominal case are validated with data from Lockheed Martin. Transient thermal analysis results of ASRG for a Venus flyby with a representative trajectory are also presented. In addition, model results of an ASRG mounted on a Cassini-like spacecraft with a sunshade are presented to show a way to mitigate the high temperatures of a Venus flyby. It was predicted that the sunshade can lower the temperature of the ASRG alternator by 20 C for the representative Venus flyby trajectory. The 3D model also was modified to predict generator performance after a single Advanced Stirling Convertor failure. The geometry of the Microtherm HT insulation block on the outboard side was modified to match deformation and shrinkage observed during testing of a prototypic ASRG test fixture by LM. Test conditions and test data were used to correlate the model by adjusting the thermal conductivity of the deformed insulation to match the post-heat-dump steady state temperatures. Results for these conditions showed that the performance of the still-functioning inboard ACS was unaffected.

Stresses in acoustically excited panels and shuttle insulation tiles

NASA Technical Reports Server (NTRS)

Otalvo, I. U.

1976-01-01

Natural vibration and acoustic response results are presented for a 36 x 18 inch panel with 18 6 x 6-inch tiles of 1.0, 1.6 and 2.3 inch thicknesses. Computed results for an untiled panel are compared with experiments performed earlier. Natural frequency and acoustic response comparisons are also given for independent analyses performed upon tiled and untiled panels. The results indicate the general applicability of the computer programs developed for use as shuttle design and analysis tools.

Measurement of health system performance at district level: A study protocol.

PubMed

Sharma, Atul; Prinja, Shankar; Aggarwal, Arun Kumar

2017-12-13

Limited efforts have been observed in low and middle income countries to undertake health system performance assessment at district level. Absence of a comprehensive data collection tool and lack of a standardised single summary measure defining overall performance are some of the main problems. Present study has been undertaken to develop a summary composite health system performance index at district level. A broad range of indicators covering all six domains as per building block framework were finalized by an expert panel. The domains were classified into twenty sub-domains, with 70 input and process indicators to measure performance. Seven sub-domains for assessing health system outputs and outcomes were identified, with a total of 28 indicators. Districts in Haryana state from north India were selected for the study. Primary and secondary data will be collected from 378 health facilities, district and state health directorate headquarters. Indicators will be normalized, aggregated to generate composite performance index at district level. Domain specific scores will present the quality of individual building block domains in the public health system. Robustness of the results will be checked using sensitivity analysis. The study presents a methodology for comprehensive assessment of all health system domains on basis of input, process, output and outcome indicators which has never been reported from India. Generation of this index will help identify policy and implementation areas of concern and point towards potential solutions. Results may also help understand relationships between individual building blocks and their sub-components.

Use of Continuous Integration Tools for Application Performance Monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vergara Larrea, Veronica G; Joubert, Wayne; Fuson, Christopher B

High performance computing systems are becom- ing increasingly complex, both in node architecture and in the multiple layers of software stack required to compile and run applications. As a consequence, the likelihood is increasing for application performance regressions to occur as a result of routine upgrades of system software components which interact in complex ways. The purpose of this study is to evaluate the effectiveness of continuous integration tools for application performance monitoring on HPC systems. In addition, this paper also describes a prototype system for application perfor- mance monitoring based on Jenkins, a Java-based continuous integration tool. The monitoringmore » system described leverages several features in Jenkins to track application performance results over time. Preliminary results and lessons learned from monitoring applications on Cray systems at the Oak Ridge Leadership Computing Facility are presented.« less

Preliminary flight-test results of an advanced technology light twin-engine airplane /ATLIT/

NASA Technical Reports Server (NTRS)

Holmes, B. J.; Kohlman, D. L.; Crane, H. L.

1976-01-01

The present status and flight-test results are presented for the ATLIT airplane. The ATLIT is a Piper PA-34 Seneca I modified by the installation of new wings incorporating the GA(W)-1 (Whitcomb) airfoil, reduced wing area, roll-control spoilers, and full-span Fowler flaps. Flight-test results on stall and spoiler roll characteristics show good agreement with wind-tunnel data. Maximum power-off lift coefficients are greater than 3.0 with flaps deflected 37 deg. With flaps down, spoiler deflections can produce roll helix angles in excess of 0.11 rad. Flight testing is planned to document climb and cruise performance, and supercritical propeller performance and noise characteristics. The airplane is scheduled for testing in the NASA-Langley Research Center Full-Scale Tunnel.

Satellite on-board processing for earth resources data

NASA Technical Reports Server (NTRS)

Bodenheimer, R. E.; Gonzalez, R. C.; Gupta, J. N.; Hwang, K.; Rochelle, R. W.; Wilson, J. B.; Wintz, P. A.

1975-01-01

Results of a survey of earth resources user applications and their data requirements, earth resources multispectral scanner sensor technology, and preprocessing algorithms for correcting the sensor outputs and for data bulk reduction are presented along with a candidate data format. Computational requirements required to implement the data analysis algorithms are included along with a review of computer architectures and organizations. Computer architectures capable of handling the algorithm computational requirements are suggested and the environmental effects of an on-board processor discussed. By relating performance parameters to the system requirements of each of the user requirements the feasibility of on-board processing is determined for each user. A tradeoff analysis is performed to determine the sensitivity of results to each of the system parameters. Significant results and conclusions are discussed, and recommendations are presented.

26 x 6.6 radial-belted aircraft tire performance

NASA Technical Reports Server (NTRS)

Davis, Pamela A.; Martinson, Veloria J.; Yager, Thomas J.; Stubbs, Sandy M.

1991-01-01

Preliminary results from testing of 26 x 6.6 radial-belted and bias-ply aircraft tires at NASA Langley's Aircraft Landing Dynamics Facility (ALDF) are reviewed. The 26 x 6.6 tire size evaluation includes cornering performance tests throughout the aircraft ground operational speed range for both dry and wet runway surfaces. Static test results to define 26 x 6.6 tire vertical stiffness properties are also presented and discussed.

Aircraft flight test trajectory control

NASA Technical Reports Server (NTRS)

Menon, P. K. A.; Walker, R. A.

1988-01-01

Two control law design techniques are compared and the performance of the resulting controllers evaluated. The design requirement is for a flight test trajectory controller (FTTC) capable of closed-loop, outer-loop control of an F-15 aircraft performing high-quality research flight test maneuvers. The maneuver modeling, linearization, and design methodologies utilized in this research, are detailed. The results of applying these FTTCs to a nonlinear F-15 simulation are presented.

Performance of an MPI-only semiconductor device simulator on a quad socket/quad core InfiniBand platform.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shadid, John Nicolas; Lin, Paul Tinphone

2009-01-01

This preliminary study considers the scaling and performance of a finite element (FE) semiconductor device simulator on a capacity cluster with 272 compute nodes based on a homogeneous multicore node architecture utilizing 16 cores. The inter-node communication backbone for this Tri-Lab Linux Capacity Cluster (TLCC) machine is comprised of an InfiniBand interconnect. The nonuniform memory access (NUMA) nodes consist of 2.2 GHz quad socket/quad core AMD Opteron processors. The performance results for this study are obtained with a FE semiconductor device simulation code (Charon) that is based on a fully-coupled Newton-Krylov solver with domain decomposition and multilevel preconditioners. Scaling andmore » multicore performance results are presented for large-scale problems of 100+ million unknowns on up to 4096 cores. A parallel scaling comparison is also presented with the Cray XT3/4 Red Storm capability platform. The results indicate that an MPI-only programming model for utilizing the multicore nodes is reasonably efficient on all 16 cores per compute node. However, the results also indicated that the multilevel preconditioner, which is critical for large-scale capability type simulations, scales better on the Red Storm machine than the TLCC machine.« less

Small passenger car transmission test; Chevrolet LUV transmission

NASA Technical Reports Server (NTRS)

Bujold, M. P.

1980-01-01

A 1978 Chevrolet LUV manual transmission tested per the applicable portions of a passenger car automatic transmission test code (SAE J65lb) which required drive performance, coast performance, and no load test conditions. Under these test conditions, the transmission attained maximum efficiencies in the upper ninety percent range for both drive performance tests and coast performance tests. The major results of this test (torque, speed, and efficiency curves) are presented. Graphs map the complete performance characteristics for the Chevrolet LUV transmission.

Small passenger car transmission test; Ford C4 transmission

NASA Technical Reports Server (NTRS)

Bujold, M. P.

1980-01-01

A 1979 Ford C4 automatic transmission was tested per a passenger car automatic transmission test code (SAE J651b) which required drive performance, coast performance, and no load test conditions. Under these test conditions, the transmission attained maximum efficiencies in the mid-eighty percent range for both drive performance tests and coast performance tests. The major results of this test (torque, speed, and efficiency curves) are presented. Graphs map the complete performance characteristics for the Ford C4 transmission.

A performability solution method for degradable nonrepairable systems

NASA Technical Reports Server (NTRS)

Furchtgott, D. G.; Meyer, J. F.

1984-01-01

The present performability model-solving algorithm identifies performance with 'reward', representing the state behavior of a system S by a finite-state stochastic process and determining reward by means of reward rates that are associated with the states of the base model. A general method is obtained for determining the probability distribution function of the performance (reward) variable, and therefore the performability, of the corresponding system. This is done for bounded utilization periods, and the result is an integral expression which is either analytically or numerically solvable.

Heat transfer evaluation in a plasma core reactor

NASA Technical Reports Server (NTRS)

Smith, D. E.; Smith, T. M.; Stoenescu, M. L.

1976-01-01

Numerical evaluations of heat transfer in a fissioning uranium plasma core reactor cavity, operating with seeded hydrogen propellant, was performed. A two-dimensional analysis is based on an assumed flow pattern and cavity wall heat exchange rate. Various iterative schemes were required by the nature of the radiative field and by the solid seed vaporization. Approximate formulations of the radiative heat flux are generally used, due to the complexity of the solution of a rigorously formulated problem. The present work analyzes the sensitivity of the results with respect to approximations of the radiative field, geometry, seed vaporization coefficients and flow pattern. The results present temperature, heat flux, density and optical depth distributions in the reactor cavity, acceptable simplifying assumptions, and iterative schemes. The present calculations, performed in cartesian and spherical coordinates, are applicable to any most general heat transfer problem.

Manganese recycling in the United States in 1998

USGS Publications Warehouse

Jones, Thomas S.

2003-01-01

This report presents the results of the U.S. Geological Survey's analytical evaluation program for six standard reference samples -- T-163 (trace constituents), M-156 (major constituents), N-67 (nutrient constituents), N-68 (nutrient constituents), P-35 (low ionic strength constituents), and Hg-31 (mercury) -- that were distributed in October 2000 to 126 laboratories enrolled in the U.S. Geological Survey sponsored interlaboratory testing program. Analytical data that were received from 122 of the laboratories were evaluated with respect to overall laboratory performance and relative laboratory performance for each analyte in the six reference samples. Results of these evaluations are presented in tabular form. Also presented are tables and graphs summarizing the analytical data provided by each laboratory for each analyte in the six standard reference samples. The most probable value for each analyte was determined using nonparametric statistics.

Design, fabrication and testing of porous tungsten vaporizers for mercury ion thrusters

NASA Technical Reports Server (NTRS)

Zavesky, R.; Kroeger, E.; Kami, S.

1983-01-01

The dispersions in the characteristics, performance and reliability of vaporizers for early model 30-cm thrusters were investigated. The purpose of the paper is to explore the findings and to discuss the approaches that were taken to reduce the observed dispersion and present the results of a program which validated those approaches. The information that is presented includes porous tungsten materials specifications, a discussion of assembly procedures, and a description of a test program which screens both material and fabrication processes. There are five appendices providing additional detail in the areas of vaporizer contamination, nitrogen flow testing, bubble testing, porosimeter testing, and mercury purity. Four neutralizers, seven cathodes and five main vaporizers were successfully fabricated, tested, and operated on thrusters. Performance data from those devices is presented and indicates extremely repeatable results from using the design and fabrication procedures.

CHARACTERIZING DETONATING LX-17 CHARGES CROSSING A TRANSVERSE AIR GAP WITH EXPERIMENTS AND MODELING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lauderbach, L M; Souers, P C; Garcia, F

2009-06-26

Experiments were performed using detonating LX-17 (92.5% TATB, 7.5% Kel-F by weight) charges with various width transverse air gaps with manganin peizoresistive in-situ gauges present. The experiments, performed with 25 mm diameter by 25 mm long LX-17 pellets with the transverse air gap in between, showed that transverse gaps up to about 3 mm could be present without causing the detonation wave to fail to continue as a detonation. The Tarantula/JWL{sup ++} code was utilized to model the results and compare with the in-situ gauge records with some agreement to the experimental data with additional work needed for a bettermore » match to the data. This work will present the experimental details as well as comparison to the model results.« less

Relationship between listeners' nonnative speech recognition and categorization abilities

PubMed Central

Atagi, Eriko; Bent, Tessa

2015-01-01

Enhancement of the perceptual encoding of talker characteristics (indexical information) in speech can facilitate listeners' recognition of linguistic content. The present study explored this indexical-linguistic relationship in nonnative speech processing by examining listeners' performance on two tasks: nonnative accent categorization and nonnative speech-in-noise recognition. Results indicated substantial variability across listeners in their performance on both the accent categorization and nonnative speech recognition tasks. Moreover, listeners' accent categorization performance correlated with their nonnative speech-in-noise recognition performance. These results suggest that having more robust indexical representations for nonnative accents may allow listeners to more accurately recognize the linguistic content of nonnative speech. PMID:25618098

Optimizing the stimulus presentation paradigm design for the P300-based brain-computer interface using performance prediction

NASA Astrophysics Data System (ADS)

Mainsah, B. O.; Reeves, G.; Collins, L. M.; Throckmorton, C. S.

2017-08-01

Objective. The role of a brain-computer interface (BCI) is to discern a user’s intended message or action by extracting and decoding relevant information from brain signals. Stimulus-driven BCIs, such as the P300 speller, rely on detecting event-related potentials (ERPs) in response to a user attending to relevant or target stimulus events. However, this process is error-prone because the ERPs are embedded in noisy electroencephalography (EEG) data, representing a fundamental problem in communication of the uncertainty in the information that is received during noisy transmission. A BCI can be modeled as a noisy communication system and an information-theoretic approach can be exploited to design a stimulus presentation paradigm to maximize the information content that is presented to the user. However, previous methods that focused on designing error-correcting codes failed to provide significant performance improvements due to underestimating the effects of psycho-physiological factors on the P300 ERP elicitation process and a limited ability to predict online performance with their proposed methods. Maximizing the information rate favors the selection of stimulus presentation patterns with increased target presentation frequency, which exacerbates refractory effects and negatively impacts performance within the context of an oddball paradigm. An information-theoretic approach that seeks to understand the fundamental trade-off between information rate and reliability is desirable. Approach. We developed a performance-based paradigm (PBP) by tuning specific parameters of the stimulus presentation paradigm to maximize performance while minimizing refractory effects. We used a probabilistic-based performance prediction method as an evaluation criterion to select a final configuration of the PBP. Main results. With our PBP, we demonstrate statistically significant improvements in online performance, both in accuracy and spelling rate, compared to the conventional row-column paradigm. Significance. By accounting for refractory effects, an information-theoretic approach can be exploited to significantly improve BCI performance across a wide range of performance levels.

Performance analysis of the ascent propulsion system of the Apollo spacecraft

NASA Technical Reports Server (NTRS)

Hooper, J. C., III

1973-01-01

Activities involved in the performance analysis of the Apollo lunar module ascent propulsion system are discussed. A description of the ascent propulsion system, including hardware, instrumentation, and system characteristics, is included. The methods used to predict the inflight performance and to establish performance uncertainties of the ascent propulsion system are discussed. The techniques of processing the telemetered flight data and performing postflight performance reconstruction to determine actual inflight performance are discussed. Problems that have been encountered and results from the analysis of the ascent propulsion system performance during the Apollo 9, 10, and 11 missions are presented.

Noninvasive evaluation system of fractured bone based on speckle interferometry

NASA Astrophysics Data System (ADS)

Yamanada, Shinya; Murata, Shigeru; Tanaka, Yohsuke

2010-11-01

This paper presents a noninvasive evaluation system of fractured bone based on speckle interferometry using a modified evaluation index for higher performance, and the experiments are carried out to examine the feasibility in evaluating bone fracture healing and the influence of some system parameters on the performance. From experimental results, it is shown that the presence of fractured part of bone and the state of bone fracture healing are successfully estimated by observing fine speckle fringes on the object surface. The proposed evaluation index also can successfully express the difference between the cases with cut and without it. Since most system parameters are found not to affect the performance of the present technique, the present technique is expected to be applied to various patients that have considerable individual variability.

TESTING AND PERFORMANCE ANALYSIS OF NASA 5 CM BY 5 CM BI-SUPPORTED SOLID OXIDE ELECTROLYSIS CELLS OPERATED IN BOTH FUEL CELL AND STEAM ELECTROLYSIS MODES

DOE Office of Scientific and Technical Information (OSTI.GOV)

R. C. O'Brien; J. E. O'Brien; C. M. Stoots

A series of 5 cm by 5 cm bi-supported Solid Oxide Electrolysis Cells (SOEC) were produced by NASA for the Idaho National Laboratory (INL) and tested under the INL High Temperature Steam Electrolysis program. The results from the experimental demonstration of cell operation for both hydrogen production and operation as fuel cells is presented. An overview of the cell technology, test apparatus and performance analysis is also provided. The INL High Temperature Steam Electrolysis laboratory has developed significant test infrastructure in support of single cell and stack performance analyses. An overview of the single cell test apparatus is presented. Themore » test data presented in this paper is representative of a first batch of NASA's prototypic 5 cm by 5 cm SOEC single cells. Clearly a significant relationship between the operational current density and cell degradation rate is evident. While the performance of these cells was lower than anticipated, in-house testing at NASA Glenn has yielded significantly higher performance and lower degradation rates with subsequent production batches of cells. Current post-test microstructure analyses of the cells tested at INL will be published in a future paper. Modification to cell compositions and cell reduction techniques will be altered in the next series of cells to be delivered to INL with the aim to decrease the cell degradation rate while allowing for higher operational current densities to be sustained. Results from the testing of new batches of single cells will be presented in a future paper.« less

Making a Difference.

ERIC Educational Resources Information Center

Panza, Carol M.

2001-01-01

Suggests that human performance technologists need to have an analysis approach to support the development of an appropriate set of improvement recommendations for clients and then move to an action plan to help them see results. Presents a performance improvement model and a systematic approach that considers organizational context, ownership,…

Self-Regulated Learning and Academic Achievement in College Students.

ERIC Educational Resources Information Center

Lindner, Reinhard W.; Harris, Bruce

This paper presents study results concerning the nature of successful academic performance, specifically examining to what extent self-regulated learning played a role in successful academic performance at the college level. (Self-regulated learning is defined as the integration and utilization of cognitive, metacognitive, motivational,…

NACUBO Endowment Study, 1995.

ERIC Educational Resources Information Center

Cambridge Associates, Inc., Boston, MA.

This report presents the results of the 1995 study of the performance and management of college and university endowments, based on 394 institutions providing data. A summary abstract provides an overview of performance and investment data; and Part 1 of the study provides a brief commentary covering endowment characteristics, historical…

Fingerprint test data report: FM 5064J (Kaiser) lots No. 1 (K) - No. 4 (K). [resin matrix composites

NASA Technical Reports Server (NTRS)

1986-01-01

Quality control tests are presented for resin matrix and carbon-carbon composites. Tests performed are filler test, resin test, prepregs test, and fabric test. The test results are presented in chart form.

Scaling of Performance in Liquid Propellant Rocket Engine Combustors

NASA Technical Reports Server (NTRS)

Hulka, James

2008-01-01

The objectives are: a) Re-introduce to you the concept of scaling; b) Describe the scaling research conducted in the 1950s and early 1960s, and present some of their conclusions; c) Narrow the focus to scaling for performance of combustion devices for liquid propellant rocket engines; and d) Present some results of subscale to full-scale performance from historical programs. Scaling is "The ability to develop new combustion devices with predictable performance on the basis of test experience with old devices." Scaling can be used to develop combustion devices of any thrust size from any thrust size. Scaling is applied mostly to increase thrust. Objective is to use scaling as a development tool. - Move injector design from an "art" to a "science"

Aerodynamic design optimization of a fuel efficient high-performance, single-engine, business airplane

NASA Technical Reports Server (NTRS)

Holmes, B. J.

1980-01-01

A design study has been conducted to optimize a single-engine airplane for a high-performance cruise mission. The mission analyzed included a cruise speed of about 300 knots, a cruise range of about 1300 nautical miles, and a six-passenger payload (5340 N (1200 lb)). The purpose of the study is to investigate the combinations of wing design, engine, and operating altitude required for the mission. The results show that these mission performance characteristics can be achieved with fuel efficiencies competitive with present-day high-performance, single- and twin-engine, business airplanes. It is noted that relaxation of the present Federal Aviation Regulation, Part 23, stall-speed requirement for single-engine airplanes facilitates the optimization of the airplane for fuel efficiency.

Study of a pursuit-evasion guidance law for high performance aircraft

NASA Technical Reports Server (NTRS)

Williams, Peggy S.; Menon, P. K. A.; Antoniewicz, Robert F.; Duke, Eugene L.

1989-01-01

The study of a one-on-one aircraft pursuit-evasion guidance scheme for high-performance aircraft is discussed. The research objective is to implement a guidance law derived earlier using differential game theory in conjunction with the theory of feedback linearization. Unlike earlier research in this area, the present formulation explicitly recognizes the two-sided nature of the pursuit-evasion scenario. The present research implements the guidance law in a realistic model of a modern high-performance fighter aircraft. Also discussed are the details of the guidance law, implementation in a highly detailed simulation of a high-performance fighter, and numerical results for two engagement geometries. Modifications of the guidance law for onboard implementation is also discussed.

Surface-based haemangioma of the tibia: a case report.

PubMed

Di Giorgio, Luigi; Valentini, Matteo Benedetti; Mastantuono, Marco; Touloupakis, Georgios

2008-12-01

We present in this paper a case of surface-based haemangioma of the tibia in a 34-year-old patient which had been misdiagnosed as periostitis. X-ray examination demonstrated a periosteal reaction, confirmed by a MRI showing a soft tissue mass adjacent to bone. We performed an incisional biopsy and made a diagnosis of haemangioma only after examining the histological results. An angiographic study was performed in order to have embolisation of the vessels, but this was not possible because of the excessive number and calibre of afferent arteries. No further symptoms arose after biopsy and therefore an en bloc or radical excision was not performed. Indications for making a correct diagnosis and performing a suitable treatment are presented below.

Session 6: Dynamic Modeling and Systems Analysis

NASA Technical Reports Server (NTRS)

Csank, Jeffrey; Chapman, Jeffryes; May, Ryan

2013-01-01

These presentations cover some of the ongoing work in dynamic modeling and dynamic systems analysis. The first presentation discusses dynamic systems analysis and how to integrate dynamic performance information into the systems analysis. The ability to evaluate the dynamic performance of an engine design may allow tradeoffs between the dynamic performance and operability of a design resulting in a more efficient engine design. The second presentation discusses the Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS). T-MATS is a Simulation system with a library containing the basic building blocks that can be used to create dynamic Thermodynamic Systems. Some of the key features include Turbo machinery components, such as turbines, compressors, etc., and basic control system blocks. T-MAT is written in the Matlab-Simulink environment and is open source software. The third presentation focuses on getting additional performance from the engine by allowing the limit regulators only to be active when a limit is danger of being violated. Typical aircraft engine control architecture is based on MINMAX scheme, which is designed to keep engine operating within prescribed mechanical/operational safety limits. Using a conditionally active min-max limit regulator scheme, additional performance can be gained by disabling non-relevant limit regulators

A time domain simulation of a beam control system

NASA Astrophysics Data System (ADS)

Mitchell, J. R.

1981-02-01

The Airborne Laser Laboratory (ALL) is being developed by the Air Force to investigate the integration and operation of high energy laser components in a dynamic airborne environment and to study the propagation of laser light from an airborne vehicle to an airborne target. The ALL is composed of several systems; among these are the Airborne Pointing and Tracking System (APT) and the Automatic Alignment System (AAS). This report presents the results of performing a time domain dynamic simulation for an integrated beam control system composed of the APT and AAS. The simulation is performed on a digital computer using the MIMIC language. It includes models of the dynamics of the system and of disturbances. Also presented in the report are the rationales and developments of these models. The data from the simulation code is summarized by several plots. In addition results from massaging the data with waveform analysis packages are presented. The results are discussed and conclusions are drawn.

Results of the U.S. Geological Survey's Analytical Evaluation Program for standard reference samples distributed in March 1999

USGS Publications Warehouse

Farrar, Jerry W.; Chleboun, Kimberly M.

1999-01-01

This report presents the results of the U.S. Geological Survey's analytical evaluation program for 8 standard reference samples -- T-157 (trace constituents), M-150 (major constituents), N-61 (nutrient constituents), N-62 (nutrient constituents), P-32 (low ionic strength constituents), GWT-5 (ground-water trace constituents), GWM- 4 (ground-water major constituents),and Hg-28 (mercury) -- that were distributed in March 1999 to 120 laboratories enrolled in the U.S. Geological Survey sponsored interlaboratory testing program. Analytical data that were received from 111 of the laboratories were evaluated with respect to overall laboratory performance and relative laboratory performance for each analyte in the seven reference samples. Results of these evaluations are presented in tabular form. Also presented are tables and graphs summarizing the analytical data provided by each laboratory for each analyte in the 8 standard reference samples. The most probable value for each analyte was determined using nonparametric statistics.

The auxiliary use of LANDSAT data in estimating crop acreages: Results of the 1975 Illinois crop-acreage experiment

NASA Technical Reports Server (NTRS)

Gleason, C. (Principal Investigator); Starbuck, R. R.; Sigman, R. S.; Hanuschak, G. A.; Craig, M. E.; Cook, P. W.; Allen, R. D.

1977-01-01

The author has identified the following significant results. It was found that classifier performance was influenced by a number of temporal, methodological, and geographical factors. Best results were obtained when corn was tasselled and near the dough stage of development. Dates earlier or later in the growing season produced poor results. Atmospheric effects on results cannot be independently measured or completely separated from the effects due to the maturity stage of the crops. Poor classifier performance was observed in areas where considerable spectral confusion was present.

Development summary of a sympathetic discharge CO2 laser for lidar use

NASA Technical Reports Server (NTRS)

Jaenisch, Holger M.; Johnson, R. Barry

1991-01-01

A commercial pulsed sympathetic discharge laser has been characterized and modified for use as a potential lidar. This report summarizes the initial findings and modifications made to the baseline system. The new laser performance is then checked with theory and operational results are presented. The laser has inherent mode instability and high chirp. Several solutions were tried and their results are presented.

Novel Three-Dimensional Vertical Interconnect Technology for Microwave and RF Applications

NASA Technical Reports Server (NTRS)

Goverdhanam, Kavita; Simons, Rainee N.; Katehi, Linda P. B.

1999-01-01

In this paper, novel 3D interconnects suitable for applications in microwave and RF integrated circuit technology have been presented. The interconnect fabrication process and design details are presented. In addition, measured and numerically modeled results of the performance of the interconnects have been shown. The results indicate that the proposed technology has tremendous potential applications in integrated circuit technology. C,

Temporal Characteristics of Radiologists' and Novices' Lesion Detection in Viewing Medical Images Presented Rapidly and Sequentially.

PubMed

Nakashima, Ryoichi; Komori, Yuya; Maeda, Eriko; Yoshikawa, Takeharu; Yokosawa, Kazuhiko

2016-01-01

Although viewing multiple stacks of medical images presented on a display is a relatively new but useful medical task, little is known about this task. Particularly, it is unclear how radiologists search for lesions in this type of image reading. When viewing cluttered and dynamic displays, continuous motion itself does not capture attention. Thus, it is effective for the target detection that observers' attention is captured by the onset signal of a suddenly appearing target among the continuously moving distractors (i.e., a passive viewing strategy). This can be applied to stack viewing tasks, because lesions often show up as transient signals in medical images which are sequentially presented simulating a dynamic and smoothly transforming image progression of organs. However, it is unclear whether observers can detect a target when the target appears at the beginning of a sequential presentation where the global apparent motion onset signal (i.e., signal of the initiation of the apparent motion by sequential presentation) occurs. We investigated the ability of radiologists to detect lesions during such tasks by comparing the performances of radiologists and novices. Results show that overall performance of radiologists is better than novices. Furthermore, the temporal locations of lesions in CT image sequences, i.e., when a lesion appears in an image sequence, does not affect the performance of radiologists, whereas it does affect the performance of novices. Results indicate that novices have greater difficulty in detecting a lesion appearing early than late in the image sequence. We suggest that radiologists have other mechanisms to detect lesions in medical images with little attention which novices do not have. This ability is critically important when viewing rapid sequential presentations of multiple CT images, such as stack viewing tasks.

Temporal Characteristics of Radiologists' and Novices' Lesion Detection in Viewing Medical Images Presented Rapidly and Sequentially

PubMed Central

Nakashima, Ryoichi; Komori, Yuya; Maeda, Eriko; Yoshikawa, Takeharu; Yokosawa, Kazuhiko

2016-01-01

Although viewing multiple stacks of medical images presented on a display is a relatively new but useful medical task, little is known about this task. Particularly, it is unclear how radiologists search for lesions in this type of image reading. When viewing cluttered and dynamic displays, continuous motion itself does not capture attention. Thus, it is effective for the target detection that observers' attention is captured by the onset signal of a suddenly appearing target among the continuously moving distractors (i.e., a passive viewing strategy). This can be applied to stack viewing tasks, because lesions often show up as transient signals in medical images which are sequentially presented simulating a dynamic and smoothly transforming image progression of organs. However, it is unclear whether observers can detect a target when the target appears at the beginning of a sequential presentation where the global apparent motion onset signal (i.e., signal of the initiation of the apparent motion by sequential presentation) occurs. We investigated the ability of radiologists to detect lesions during such tasks by comparing the performances of radiologists and novices. Results show that overall performance of radiologists is better than novices. Furthermore, the temporal locations of lesions in CT image sequences, i.e., when a lesion appears in an image sequence, does not affect the performance of radiologists, whereas it does affect the performance of novices. Results indicate that novices have greater difficulty in detecting a lesion appearing early than late in the image sequence. We suggest that radiologists have other mechanisms to detect lesions in medical images with little attention which novices do not have. This ability is critically important when viewing rapid sequential presentations of multiple CT images, such as stack viewing tasks. PMID:27774080

Performance of fully-coupled algebraic multigrid preconditioners for large-scale VMS resistive MHD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, P. T.; Shadid, J. N.; Hu, J. J.

Here, we explore the current performance and scaling of a fully-implicit stabilized unstructured finite element (FE) variational multiscale (VMS) capability for large-scale simulations of 3D incompressible resistive magnetohydrodynamics (MHD). The large-scale linear systems that are generated by a Newton nonlinear solver approach are iteratively solved by preconditioned Krylov subspace methods. The efficiency of this approach is critically dependent on the scalability and performance of the algebraic multigrid preconditioner. Our study considers the performance of the numerical methods as recently implemented in the second-generation Trilinos implementation that is 64-bit compliant and is not limited by the 32-bit global identifiers of themore » original Epetra-based Trilinos. The study presents representative results for a Poisson problem on 1.6 million cores of an IBM Blue Gene/Q platform to demonstrate very large-scale parallel execution. Additionally, results for a more challenging steady-state MHD generator and a transient solution of a benchmark MHD turbulence calculation for the full resistive MHD system are also presented. These results are obtained on up to 131,000 cores of a Cray XC40 and one million cores of a BG/Q system.« less

Performance of fully-coupled algebraic multigrid preconditioners for large-scale VMS resistive MHD

DOE PAGES

Lin, P. T.; Shadid, J. N.; Hu, J. J.; ...

2017-11-06

Here, we explore the current performance and scaling of a fully-implicit stabilized unstructured finite element (FE) variational multiscale (VMS) capability for large-scale simulations of 3D incompressible resistive magnetohydrodynamics (MHD). The large-scale linear systems that are generated by a Newton nonlinear solver approach are iteratively solved by preconditioned Krylov subspace methods. The efficiency of this approach is critically dependent on the scalability and performance of the algebraic multigrid preconditioner. Our study considers the performance of the numerical methods as recently implemented in the second-generation Trilinos implementation that is 64-bit compliant and is not limited by the 32-bit global identifiers of themore » original Epetra-based Trilinos. The study presents representative results for a Poisson problem on 1.6 million cores of an IBM Blue Gene/Q platform to demonstrate very large-scale parallel execution. Additionally, results for a more challenging steady-state MHD generator and a transient solution of a benchmark MHD turbulence calculation for the full resistive MHD system are also presented. These results are obtained on up to 131,000 cores of a Cray XC40 and one million cores of a BG/Q system.« less

SeaWiFS Technical Report Series. Volume 22: Prelaunch Acceptance Report for the SeaWiFS Radiometer

NASA Technical Reports Server (NTRS)

Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Acker, James G. (Editor); Barnes, Robert A.; Barnes, William L.; Esaias, Wayne E.; Mcclain, Charles R.

1994-01-01

The final acceptance, or rejection, of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) will be determined by the instrument's on-orbit operation. There is, however, an extensive set of laboratory measurements describing the operating characteristics of the radiometer. Many of the requirements in the Ocean Color Data Mission (OCDM) specifications can be checked only by laboratory measurements. Here, the calibration review panel examines the laboratory characterization and calibration of SeaWiFS in the light of the OCDM performance specification. Overall, the performance of the SeaWiFS instrument meets or exceeds the requirements of the OCDM contract in all but a few unimportant details. The detailed results of this examination are presented here by following the outline of the specifications, as found in the Contract. The results are presented in the form of requirements and compliance pairs. These results give conclusions on many, but not all, of the performance specifications. The acceptance by this panel of the performance of SeaWiFS must only be considered as an intermediate conclusion. The ultimate acceptance (or rejection) of the SeaWiFS data set will rely on the measurements made by the instrument on orbit.

Performance evaluation capabilities for the design of physical systems

NASA Technical Reports Server (NTRS)

Pilkey, W. D.; Wang, B. P.

1972-01-01

The results are presented of a study aimed at developing and formulating a capability for the limiting performance of large steady state systems. The accomplishments reported include: (1) development of a theory of limiting performance of large systems subject to steady state inputs; (2) application and modification of PERFORM, the computational capability for the limiting performance of systems with transient inputs; and (3) demonstration that use of an inherently smooth control force for a limiting performance calculation improves the system identification phase of the design process for physical systems subjected to transient loading.

Improved methods of performing coherent optical correlation

NASA Technical Reports Server (NTRS)

Husain-Abidi, A. S.

1972-01-01

Coherent optical correlators are described in which complex spatial filters are recorded by a quasi-Fourier transform method. The high-pass spatial filtering effects (due to the dynamic range of photographic films) normally encountered in Vander Lugt type complex filters are not present in this system. Experimental results for both transmittive as well as reflective objects are presented. Experiments are also performed by illuminating the object with diffused light. A correlator using paraboloidal mirror segments as the Fourier-transforming element is also described.

Heatshield for Extreme Entry Environment Technology: Results from Acreage and Integrated Seams Arcjet Testing

NASA Technical Reports Server (NTRS)

Venkatapathy, Ethiraj

2016-01-01

This invited talk will give a brief overview of the integrated heat-shield system design that requires seams and the extreme environment conditions that HEEET should be demonstrated to be capable of thermal performance without fail. We have tested HEEET across many different facilities and at conditions that are extreme. The presentation will highlight the performance of both the acreage as well as integrated seam at these conditions. The Invite talks are 10 min and hence this presentation will be short.

Application of the GNU Radio platform in the multistatic radar

NASA Astrophysics Data System (ADS)

Szlachetko, Boguslaw; Lewandowski, Andrzej

2009-06-01

This document presents the application of the Software Defined Radio-based platform in the multistatic radar. This platform consists of four-sensor linear antenna, Universal Software Radio Peripheral (USRP) hardware (radio frequency frontend) and GNU-Radio PC software. The paper provides information about architecture of digital signal processing performed by USRP's FPGA (digital down converting blocks) and PC host (implementation of the multichannel digital beamforming). The preliminary results of the signal recording performed by our experimental platform are presented.

Dynamic competitive probabilistic principal components analysis.

PubMed

López-Rubio, Ezequiel; Ortiz-DE-Lazcano-Lobato, Juan Miguel

2009-04-01

We present a new neural model which extends the classical competitive learning (CL) by performing a Probabilistic Principal Components Analysis (PPCA) at each neuron. The model also has the ability to learn the number of basis vectors required to represent the principal directions of each cluster, so it overcomes a drawback of most local PCA models, where the dimensionality of a cluster must be fixed a priori. Experimental results are presented to show the performance of the network with multispectral image data.

A Modified Rodrigues Parameter-based Nonlinear Observer Design for Spacecraft Gyroscope Parameters Estimation

NASA Astrophysics Data System (ADS)

Yong, Kilyuk; Jo, Sujang; Bang, Hyochoong

This paper presents a modified Rodrigues parameter (MRP)-based nonlinear observer design to estimate bias, scale factor and misalignment of gyroscope measurements. A Lyapunov stability analysis is carried out for the nonlinear observer. Simulation is performed and results are presented illustrating the performance of the proposed nonlinear observer under the condition of persistent excitation maneuver. In addition, a comparison between the nonlinear observer and alignment Kalman filter (AKF) is made to highlight favorable features of the nonlinear observer.

Near-term hybrid vehicle program, phase 1. Appendix A: Mission analysis and performance specification studies report

NASA Technical Reports Server (NTRS)

1979-01-01

Results of a study leading to the preliminary design of a five passenger hybrid vehicle utilizing two energy sources (electricity and gasoline/diesel fuel) to minimize petroleum usage on a fleet basis are presented. The study methodology is described. Vehicle characterizations, the mission description, characterization, and impact on potential sales, and the rationale for the selection of the reference internal combustion engine vehicle are presented. Conclusions and recommendations of the mission analysis and performance specification report are included.

Assessment of theory of mind in children with communication disorders: role of presentation mode.

PubMed

van Buijsen, Marit; Hendriks, Angelique; Ketelaars, Mieke; Verhoeven, Ludo

2011-01-01

Children with communication disorders have problems with both language and social interaction. The theory-of-mind hypothesis provides an explanation for these problems, and different tests have been developed to test this hypothesis. However, different modes of presentation are used in these tasks, which make the results difficult to compare. In the present study, the performances of typically developing children, children with specific language impairments, and children with autism spectrum disorders were therefore compared using three theory-of-mind tests (the Charlie test, the Smarties test, and the Sally-and-Anne test) presented in three different manners each (spoken, video, and line drawing modes). The results showed differential outcomes for the three types of tests and a significant interaction between group of children and mode of presentation. For the typically developing children, no differential effects of presentation mode were detected. For the children with SLI, the highest test scores were consistently evidenced in the line-drawing mode. For the children with ASD, test performance depended on the mode of presentation. Just how the children's non-verbal age, verbal age, and short-term memory related to their test scores was also explored for each group of children. The test scores of the SLI group correlated significantly with their short-term memory, those of the ASD group with their verbal age. These findings demonstrate that performance on theory-of-mind tests clearly depend upon mode of test presentation as well as the children's cognitive and linguistic abilities. Copyright © 2011 Elsevier Ltd. All rights reserved.

Enhanced Component Performance Study. Emergency Diesel Generators 1998–2013

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schroeder, John Alton

2014-11-01

This report presents an enhanced performance evaluation of emergency diesel generators (EDGs) at U.S. commercial nuclear power plants. This report evaluates component performance over time using Institute of Nuclear Power Operations (INPO) Consolidated Events Database (ICES) data from 1998 through 2013 and maintenance unavailability (UA) performance data using Mitigating Systems Performance Index (MSPI) Basis Document data from 2002 through 2013. The objective is to present an analysis of factors that could influence the system and component trends in addition to annual performance trends of failure rates and probabilities. The factors analyzed for the EDG component are the differences in failuresmore » between all demands and actual unplanned engineered safety feature (ESF) demands, differences among manufacturers, and differences among EDG ratings. Statistical analyses of these differences are performed and results showing whether pooling is acceptable across these factors. In addition, engineering analyses were performed with respect to time period and failure mode. The factors analyzed are: sub-component, failure cause, detection method, recovery, manufacturer, and EDG rating.« less

Results and Implications of Seven Years of the University of Arizona Astronomy Club

NASA Astrophysics Data System (ADS)

Walker-LaFollette, Amanda; Towner, A. P.; Hardegree-Ullman, K.; Brissenden, G.

2014-01-01

Participation in an undergraduate astronomy club or organization, be it social, academic, outreach-, or research-oriented, can be extremely beneficial to astronomy students. In this talk, we present the numerical results of the past seven years of University of Arizona Astronomy Club activities, particularly those relating to published papers, poster presentations, attendance at AAS meetings, and retention within the major. We also discuss less-quantifiable results, such as social, academic, and emotional support for club members. Finally, we highlight the efforts being performed by undergraduates at institutions all around the country, as presented in this Session.

LaRC design analysis report for National Transonic Facility for 304 stainless steel tunnel shell. Volume 1S: Finite difference analysis of cone/cylinder junction

NASA Technical Reports Server (NTRS)

Ramsey, J. W., Jr.; Taylor, J. T.; Wilson, J. F.; Gray, C. E., Jr.; Leatherman, A. D.; Rooker, J. R.; Allred, J. W.

1976-01-01

The results of extensive computer (finite element, finite difference and numerical integration), thermal, fatigue, and special analyses of critical portions of a large pressurized, cryogenic wind tunnel (National Transonic Facility) are presented. The computer models, loading and boundary conditions are described. Graphic capability was used to display model geometry, section properties, and stress results. A stress criteria is presented for evaluation of the results of the analyses. Thermal analyses were performed for major critical and typical areas. Fatigue analyses of the entire tunnel circuit are presented.

Novel types of surface acoustic wave microreflectors - Performance analysis and simulations

NASA Astrophysics Data System (ADS)

Golan, G.; Griffel, G.; Seidman, A.; Croitoru, N.

1990-06-01

Surface acoustic waves for micrograting reflectors have been characterized. Based on the perturbation theory, eight different types of structures on an acoustic waveguide were analyzed. Results of simulations of all eight types of corrugation structures were evaluated in order to find the least leaky waveguide, the most efficient reflector (with minimum necessary perturbations), and the optimal mode shape for improved performances. General design curves are presented in order to illustrate the behavior of the incident and reflected waves under a variety of structural conditions. Analytic expressions for the calculations of the mode amplitude and mode shape, and for general acoustic corrugations are derived and then the simulations results are presented.

Optimization study for high speed radial turbine with special reference to design variables

NASA Technical Reports Server (NTRS)

Khalil, I.; Tabakoff, W.

1977-01-01

Numerical results of a theoretical investigation are presented to provide information about the effect of variation of the different design and operating parameters on radial inflow turbine performance. The effects of variations in the mass flow rate, rotor tip Mach number, inlet flow angles, number of rotor blades and hub to shroud radius ratio, on the internal fluid dynamics of turbine rotors, was investigated. A procedure to estimate the flow deviation angles at the turbine exit is also presented and used to examine the influence of the operating conditions and the rotor geometrical configuration on these deviations. The significance of the results obtained is discussed with respect to improved turbine performance.

Robust human machine interface based on head movements applied to assistive robotics.

PubMed

Perez, Elisa; López, Natalia; Orosco, Eugenio; Soria, Carlos; Mut, Vicente; Freire-Bastos, Teodiano

2013-01-01

This paper presents an interface that uses two different sensing techniques and combines both results through a fusion process to obtain the minimum-variance estimator of the orientation of the user's head. Sensing techniques of the interface are based on an inertial sensor and artificial vision. The orientation of the user's head is used to steer the navigation of a robotic wheelchair. Also, a control algorithm for assistive technology system is presented. The system is evaluated by four individuals with severe motors disability and a quantitative index was developed, in order to objectively evaluate the performance. The results obtained are promising since most users could perform the proposed tasks with the robotic wheelchair.

Robust Human Machine Interface Based on Head Movements Applied to Assistive Robotics

PubMed Central

Perez, Elisa; López, Natalia; Orosco, Eugenio; Soria, Carlos; Mut, Vicente; Freire-Bastos, Teodiano

2013-01-01

This paper presents an interface that uses two different sensing techniques and combines both results through a fusion process to obtain the minimum-variance estimator of the orientation of the user's head. Sensing techniques of the interface are based on an inertial sensor and artificial vision. The orientation of the user's head is used to steer the navigation of a robotic wheelchair. Also, a control algorithm for assistive technology system is presented. The system is evaluated by four individuals with severe motors disability and a quantitative index was developed, in order to objectively evaluate the performance. The results obtained are promising since most users could perform the proposed tasks with the robotic wheelchair. PMID:24453877

OARE STS-94 (MSL-1R)

NASA Technical Reports Server (NTRS)

Rice, James E.

1998-01-01

The report is organized into sections representing the phases of work performed in analyzing the STS-94 (MSL-IR) results. STS-94 (MSL1R) is a reflight of the STS-83 (MSL-1) mission which was terminated early because of a fuel cell problem. Section I briefly outlines the OARE system features, coordinates, and measurement parameters. Section 2 describes the results from STS-94. The mission description, data calibration, and representative data obtained on STS-94 are presented. Also, the anomalous performance of OARE on STS-94 is discussed. Finally, Section 3 presents a discussion of accuracy achieved and achievable with OARE. Appendix A discuss the calibration and data processing methodology in detail.

Computational study of single-expansion-ramp nozzles with external burning

NASA Astrophysics Data System (ADS)

Yungster, Shaye; Trefny, Charles J.

1992-04-01

A computational investigation of the effects of external burning on the performance of single expansion ramp nozzles (SERN) operating at transonic speeds is presented. The study focuses on the effects of external heat addition and introduces a simplified injection and mixing model based on a control volume analysis. This simplified model permits parametric and scaling studies that would have been impossible to conduct with a detailed CFD analysis. The CFD model is validated by comparing the computed pressure distribution and thrust forces, for several nozzle configurations, with experimental data. Specific impulse calculations are also presented which indicate that external burning performance can be superior to other methods of thrust augmentation at transonic speeds. The effects of injection fuel pressure and nozzle pressure ratio on the performance of SERN nozzles with external burning are described. The results show trends similar to those reported in the experimental study, and provide additional information that complements the experimental data, improving our understanding of external burning flowfields. A study of the effect of scale is also presented. The results indicate that combustion kinetics do not make the flowfield sensitive to scale.

A Model-Based Anomaly Detection Approach for Analyzing Streaming Aircraft Engine Measurement Data

NASA Technical Reports Server (NTRS)

Simon, Donald L.; Rinehart, Aidan W.

2014-01-01

This paper presents a model-based anomaly detection architecture designed for analyzing streaming transient aircraft engine measurement data. The technique calculates and monitors residuals between sensed engine outputs and model predicted outputs for anomaly detection purposes. Pivotal to the performance of this technique is the ability to construct a model that accurately reflects the nominal operating performance of the engine. The dynamic model applied in the architecture is a piecewise linear design comprising steady-state trim points and dynamic state space matrices. A simple curve-fitting technique for updating the model trim point information based on steadystate information extracted from available nominal engine measurement data is presented. Results from the application of the model-based approach for processing actual engine test data are shown. These include both nominal fault-free test case data and seeded fault test case data. The results indicate that the updates applied to improve the model trim point information also improve anomaly detection performance. Recommendations for follow-on enhancements to the technique are also presented and discussed.

A Model-Based Anomaly Detection Approach for Analyzing Streaming Aircraft Engine Measurement Data

NASA Technical Reports Server (NTRS)

Simon, Donald L.; Rinehart, Aidan Walker

2015-01-01

This paper presents a model-based anomaly detection architecture designed for analyzing streaming transient aircraft engine measurement data. The technique calculates and monitors residuals between sensed engine outputs and model predicted outputs for anomaly detection purposes. Pivotal to the performance of this technique is the ability to construct a model that accurately reflects the nominal operating performance of the engine. The dynamic model applied in the architecture is a piecewise linear design comprising steady-state trim points and dynamic state space matrices. A simple curve-fitting technique for updating the model trim point information based on steadystate information extracted from available nominal engine measurement data is presented. Results from the application of the model-based approach for processing actual engine test data are shown. These include both nominal fault-free test case data and seeded fault test case data. The results indicate that the updates applied to improve the model trim point information also improve anomaly detection performance. Recommendations for follow-on enhancements to the technique are also presented and discussed.

Artificial Intelligence (AI) Based Tactical Guidance for Fighter Aircraft

NASA Technical Reports Server (NTRS)

McManus, John W.; Goodrich, Kenneth H.

1990-01-01

A research program investigating the use of Artificial Intelligence (AI) techniques to aid in the development of a Tactical Decision Generator (TDG) for Within Visual Range (WVR) air combat engagements is discussed. The application of AI programming and problem solving methods in the development and implementation of the Computerized Logic For Air-to-Air Warfare Simulations (CLAWS), a second generation TDG, is presented. The Knowledge-Based Systems used by CLAWS to aid in the tactical decision-making process are outlined in detail, and the results of tests to evaluate the performance of CLAWS versus a baseline TDG developed in FORTRAN to run in real-time in the Langley Differential Maneuvering Simulator (DMS), are presented. To date, these test results have shown significant performance gains with respect to the TDG baseline in one-versus-one air combat engagements, and the AI-based TDG software has proven to be much easier to modify and maintain than the baseline FORTRAN TDG programs. Alternate computing environments and programming approaches, including the use of parallel algorithms and heterogeneous computer networks are discussed, and the design and performance of a prototype concurrent TDG system are presented.

Computational study of single-expansion-ramp nozzles with external burning

NASA Technical Reports Server (NTRS)

Yungster, Shaye; Trefny, Charles J.

1992-01-01

A computational investigation of the effects of external burning on the performance of single expansion ramp nozzles (SERN) operating at transonic speeds is presented. The study focuses on the effects of external heat addition and introduces a simplified injection and mixing model based on a control volume analysis. This simplified model permits parametric and scaling studies that would have been impossible to conduct with a detailed CFD analysis. The CFD model is validated by comparing the computed pressure distribution and thrust forces, for several nozzle configurations, with experimental data. Specific impulse calculations are also presented which indicate that external burning performance can be superior to other methods of thrust augmentation at transonic speeds. The effects of injection fuel pressure and nozzle pressure ratio on the performance of SERN nozzles with external burning are described. The results show trends similar to those reported in the experimental study, and provide additional information that complements the experimental data, improving our understanding of external burning flowfields. A study of the effect of scale is also presented. The results indicate that combustion kinetics do not make the flowfield sensitive to scale.

Contribution of variable-speed pump hydro storage for power system dynamic performance

NASA Astrophysics Data System (ADS)

Silva, B.; Moreira, C.

2017-04-01

This paper presents the study of variable-speed Pump Storage Powerplant (PSP) in the Portuguese power system. It evaluates the progressive integration in three major locations and compares the power system performance following a severe fault event with consequent disconnection of non-Fault Ride-through (FRT) compliant Wind Farms (WF). To achieve such objective, a frequency responsive model was developed in PSS/E and was further used to substitute existing fixed-speed PSP. The results allow identifying a clear enhancement on the power system performance by the presence of frequency responsive variable-speed PSP, especially for the scenario presented, with high level of renewables integration.

Performance documentation of the engineering model 30-cm diameter thruster

NASA Technical Reports Server (NTRS)

Bechtel, R. T.; Rawlin, V. K.

1976-01-01

The results of extensive testing of two 30-cm ion thrusters which are virtually identical to the 900 series Engineering Model Thruster in an ongoing 15,000-hour life test are presented. Performance data for the nominal fullpower (2650 W) operating point; performance sensitivities to discharge voltage, discharge losses, accelerator voltage, and magnetic baffle current; and several power throttling techniques (maximum Isp, maximum thrust/power ratio, and two cases in between are included). Criteria for throttling are specified in terms of the screen power supply envelope, thruster operating limits, and control stability. In addition, reduced requirements for successful high voltage recycles are presented.

Helicopter rotor and engine sizing for preliminary performance estimation

NASA Technical Reports Server (NTRS)

Talbot, P. D.; Bowles, J. V.; Lee, H. C.

1986-01-01

Methods are presented for estimating some of the more fundamental design variables of single-rotor helicopters (tip speed, blade area, disk loading, and installed power) based on design requirements (speed, weight, fuselage drag, and design hover ceiling). The well-known constraints of advancing-blade compressibility and retreating-blade stall are incorporated into the estimation process, based on an empirical interpretation of rotor performance data from large-scale wind-tunnel tests. Engine performance data are presented and correlated with a simple model usable for preliminary design. When approximate results are required quickly, these methods may be more convenient to use and provide more insight than large digital computer programs.

Dynamical genetic programming in XCSF.

PubMed

Preen, Richard J; Bull, Larry

2013-01-01

A number of representation schemes have been presented for use within learning classifier systems, ranging from binary encodings to artificial neural networks. This paper presents results from an investigation into using a temporally dynamic symbolic representation within the XCSF learning classifier system. In particular, dynamical arithmetic networks are used to represent the traditional condition-action production system rules to solve continuous-valued reinforcement learning problems and to perform symbolic regression, finding competitive performance with traditional genetic programming on a number of composite polynomial tasks. In addition, the network outputs are later repeatedly sampled at varying temporal intervals to perform multistep-ahead predictions of a financial time series.

Relations of Machiavellian behavior with sales performance of stockbrokers.

PubMed

Aziz, Abdul; May, Kim; Crotts, John C

2002-04-01

The hypothesis of a relationship between Machiavellian behavior and sales performance of Christie and Geis was tested with a sample of 110 stockbrokers. Scores on a measure called the Machiavellian Behavior scale were positively and significantly correlated with two self-reported measures of sales performance of the stock-brokers. Present results together with those of two earlier studies supported the hypothesis that salespeople with a Machiavellian orientation are likely to be more sucessful. Analysis of the data also indicated predictive validity and acceptable internal consistency of the Machiavellian Behavior scale. Limitations of the present study and a need for further research are discussed.

An approach to quality and performance control in a computer-assisted clinical chemistry laboratory.

PubMed Central

Undrill, P E; Frazer, S C

1979-01-01

A locally developed, computer-based clinical chemistry laboratory system has been in operation since 1970. This utilises a Digital Equipment Co Ltd PDP 12 and an interconnected PDP 8/F computer. Details are presented of the performance and quality control techniques incorporated into the system. Laboratory performance is assessed through analysis of results from fixed-level control sera as well as from cumulative sum methods. At a simple level the presentation may be considered purely indicative, while at a more sophisticated level statistical concepts have been introduced to aid the laboratory controller in decision-making processes. PMID:438340

Comparison among mathematical models of the photovoltaic cell for computer simulation purposes

NASA Astrophysics Data System (ADS)

Tofoli, Fernando Lessa; Pereira, Denis de Castro; Josias De Paula, Wesley; Moreira Vicente, Eduardo; Vicente, Paula dos Santos; Braga, Henrique Antonio Carvalho

2017-07-01

This paper presents a comparison among mathematical models used in the simulation of solar photovoltaic modules that can be easily integrated with power electronic converters. In order to perform the analysis, three models available in literature and also the physical model of the module in software PSIM® are used. Some results regarding the respective I × V and P × V curves are presented, while some advantages and eventual limitations are discussed. Besides, a DC-DC buck converter performs maximum power point tracking by using perturb and observe method, while the performance of each one of the aforementioned models is investigated.

Performance of 10-kW class xenon ion thrusters

NASA Technical Reports Server (NTRS)

Patterson, Michael J.; Rawlin, Vincent K.

1988-01-01

Presented are performance data for laboratory and engineering model 30 cm-diameter ion thrusters operated with xenon propellant over a range of input power levels from approximately 2 to 20 kW. Also presented are preliminary performance results obtained from laboratory model 50 cm-diameter cusp- and divergent-field ion thrusters operating with both 30 cm- amd 50 cm-diameter ion optics up to a 20 kW input power. These data include values of discharge chamber propellant and power efficiencies, as well as values of specific impulse, thruster efficiency, thrust and power. The operation of the 30 cm- and 50 cm-diameter ion optics are also discussed.

Simulation verification techniques study. Subsystem simulation validation techniques

NASA Technical Reports Server (NTRS)

Duncan, L. M.; Reddell, J. P.; Schoonmaker, P. B.

1974-01-01

Techniques for validation of software modules which simulate spacecraft onboard systems are discussed. An overview of the simulation software hierarchy for a shuttle mission simulator is provided. A set of guidelines for the identification of subsystem/module performance parameters and critical performance parameters are presented. Various sources of reference data to serve as standards of performance for simulation validation are identified. Environment, crew station, vehicle configuration, and vehicle dynamics simulation software are briefly discussed from the point of view of their interfaces with subsystem simulation modules. A detailed presentation of results in the area of vehicle subsystems simulation modules is included. A list of references, conclusions and recommendations are also given.

Elliptical orbit performance computer program

NASA Technical Reports Server (NTRS)

Myler, T. R.

1981-01-01

A FORTRAN coded computer program which generates and plots elliptical orbit performance capability of space boosters for presentation purposes is described. Orbital performance capability of space boosters is typically presented as payload weight as a function of perigee and apogee altitudes. The parameters are derived from a parametric computer simulation of the booster flight which yields the payload weight as a function of velocity and altitude at insertion. The process of converting from velocity and altitude to apogee and perigee altitude and plotting the results as a function of payload weight is mechanized with the ELOPE program. The program theory, user instruction, input/output definitions, subroutine descriptions and detailed FORTRAN coding information are included.

CPMIP: measurements of real computational performance of Earth system models in CMIP6

NASA Astrophysics Data System (ADS)

Balaji, Venkatramani; Maisonnave, Eric; Zadeh, Niki; Lawrence, Bryan N.; Biercamp, Joachim; Fladrich, Uwe; Aloisio, Giovanni; Benson, Rusty; Caubel, Arnaud; Durachta, Jeffrey; Foujols, Marie-Alice; Lister, Grenville; Mocavero, Silvia; Underwood, Seth; Wright, Garrett

2017-01-01

A climate model represents a multitude of processes on a variety of timescales and space scales: a canonical example of multi-physics multi-scale modeling. The underlying climate system is physically characterized by sensitive dependence on initial conditions, and natural stochastic variability, so very long integrations are needed to extract signals of climate change. Algorithms generally possess weak scaling and can be I/O and/or memory-bound. Such weak-scaling, I/O, and memory-bound multi-physics codes present particular challenges to computational performance. Traditional metrics of computational efficiency such as performance counters and scaling curves do not tell us enough about real sustained performance from climate models on different machines. They also do not provide a satisfactory basis for comparative information across models. codes present particular challenges to computational performance. We introduce a set of metrics that can be used for the study of computational performance of climate (and Earth system) models. These measures do not require specialized software or specific hardware counters, and should be accessible to anyone. They are independent of platform and underlying parallel programming models. We show how these metrics can be used to measure actually attained performance of Earth system models on different machines, and identify the most fruitful areas of research and development for performance engineering. codes present particular challenges to computational performance. We present results for these measures for a diverse suite of models from several modeling centers, and propose to use these measures as a basis for a CPMIP, a computational performance model intercomparison project (MIP).

Integrated vehicle-based safety systems heavy truck field operational test, methodology and results report.

DOT National Transportation Integrated Search

2010-12-01

"This document presents the methodology and results from the heavy-truck field operational test conducted as part of the Integrated Vehicle-Based Safety Systems program. These findings are the result of analyses performed by the University of Michiga...

Integrated vehicle-based safety systems light-vehicle field operational test, methodology and results report.

DOT National Transportation Integrated Search

2010-12-01

"This document presents the methodology and results from the light-vehicle field operational test conducted as part of the Integrated Vehicle-Based Safety Systems program. These findings are the result of analyses performed by the University of Michi...

Rail-highway crossing accident prediction research results - FY80

DOT National Transportation Integrated Search

1981-01-01

This report presents the results of research performed at the : Transportation Systems Center (TSC) dealing with mathematical : methods of predicting accidents at rail-highway crossings. The : work consists of three parts : Part I - Revised DOT Accid...

Aircraft symmetric flight optimization. [gradient techniques for supersonic aircraft control

NASA Technical Reports Server (NTRS)

Falco, M.; Kelley, H. J.

1973-01-01

Review of the development of gradient techniques and their application to aircraft optimal performance computations in the vertical plane of flight. Results obtained using the method of gradients are presented for attitude- and throttle-control programs which extremize the fuel, range, and time performance indices subject to various trajectory and control constraints, including boundedness of engine throttle control. A penalty function treatment of state inequality constraints which generally appear in aircraft performance problems is outlined. Numerical results for maximum-range, minimum-fuel, and minimum-time climb paths for a hypothetical supersonic turbojet interceptor are presented and discussed. In addition, minimum-fuel climb paths subject to various levels of ground overpressure intensity constraint are indicated for a representative supersonic transport. A variant of the Gel'fand-Tsetlin 'method of ravines' is reviewed, and two possibilities for further development of continuous gradient processes are cited - namely, a projection version of conjugate gradients and a curvilinear search.

Probabilistic Asteroid Impact Risk Assessment for the Hypothetical PDC17 Impact Exercise

NASA Technical Reports Server (NTRS)

Wheeler, Lorien; Mathias, Donovan

2017-01-01

Performing impact risk assessment for the 2017 Planetary Defense Conference (PDC17) hypothetical impact exercise, to take place at the PDC17 conference, May 15-20, 2017. Impact scenarios and trajectories are developed and provided by NASA's Near Earth Objects Office at JPL (Paul Chodas). These results represent purely hypothetical impact scenarios, and do not reflect any known asteroid threat. Risk assessment was performed using the Probabilistic Asteroid Impact Risk (PAIR) model developed by the Asteroid Threat Assessment Project (ATAP) at NASA Ames Research Center. This presentation includes sample results that may be presented or used in discussions during the various stages of the impact exercisecenter dot Some cases represent alternate scenario options that may not be used during the actual impact exercise at the PDC17 conference. Updates to these initial assessments and/or additional scenario assessments may be performed throughout the impact exercise as different scenario options unfold.

Knobology in use: an experimental evaluation of ergonomics recommendations.

PubMed

Overgård, Kjell Ivar; Fostervold, Knut Inge; Bjelland, Hans Vanhauwaert; Hoff, Thomas

2007-05-01

The scientific basis for ergonomics recommendations for controls has usually not been related to active goal-directed use. The present experiment tests how different knob sizes and torques affect operator performance. The task employed is to control a pointer by the use of a control knob, and is as such an experimentally defined goal-directed task relevant to machine systems in general. Duration of use, error associated with use (overshooting of the goal area) and movement reproduction were used as performance measures. Significant differences between knob sizes were found for movement reproduction. High torques led to less overshooting as opposed to low torques. The results from duration of use showed a tendency that the differences between knob sizes were reduced from the first iteration to the second iteration. The present results indicate that the ergonomically recommended ranges of knob sizes might differently affect operator performance.

Distributed control of large space antennas

NASA Technical Reports Server (NTRS)

Cameron, J. M.; Hamidi, M.; Lin, Y. H.; Wang, S. J.

1983-01-01

A systematic way to choose control design parameters and to evaluate performance for large space antennas is presented. The structural dynamics and control properties for a Hoop and Column Antenna and a Wrap-Rib Antenna are characterized. Some results of the effects of model parameter uncertainties to the stability, surface accuracy, and pointing errors are presented. Critical dynamics and control problems for these antenna configurations are identified and potential solutions are discussed. It was concluded that structural uncertainties and model error can cause serious performance deterioration and can even destabilize the controllers. For the hoop and column antenna, large hoop and long meat and the lack of stiffness between the two substructures result in low structural frequencies. Performance can be improved if this design can be strengthened. The two-site control system is more robust than either single-site control systems for the hoop and column antenna.

Tracking accuracy assessment for concentrator photovoltaic systems

NASA Astrophysics Data System (ADS)

Norton, Matthew S. H.; Anstey, Ben; Bentley, Roger W.; Georghiou, George E.

2010-10-01

The accuracy to which a concentrator photovoltaic (CPV) system can track the sun is an important parameter that influences a number of measurements that indicate the performance efficiency of the system. This paper presents work carried out into determining the tracking accuracy of a CPV system, and illustrates the steps involved in gaining an understanding of the tracking accuracy. A Trac-Stat SL1 accuracy monitor has been used in the determination of pointing accuracy and has been integrated into the outdoor CPV module test facility at the Photovoltaic Technology Laboratories in Nicosia, Cyprus. Results from this work are provided to demonstrate how important performance indicators may be presented, and how the reliability of results is improved through the deployment of such accuracy monitors. Finally, recommendations on the use of such sensors are provided as a means to improve the interpretation of real outdoor performance.

Performance analysis for mixed FSO/RF Nakagami-m and Exponentiated Weibull dual-hop airborne systems

NASA Astrophysics Data System (ADS)

Jing, Zhao; Shang-hong, Zhao; Wei-hu, Zhao; Ke-fan, Chen

2017-06-01

In this paper, the performances of mixed free-space optical (FSO)/radio frequency (RF) systems are presented based on the decode-and-forward relaying. The Exponentiated Weibull fading channel with pointing error effect is adopted for the atmospheric fluctuation of FSO channel and the RF link undergoes the Nakagami-m fading. We derived the analytical expression for cumulative distribution function (CDF) of equivalent signal-to-noise ratio (SNR). The novel mathematical presentations of outage probability and average bit-error-rate (BER) are developed based on the Meijer's G function. The analytical results show an accurately match to the Monte-Carlo simulation results. The outage and BER performance for the mixed system by decode-and-forward relay are investigated considering atmospheric turbulence and pointing error condition. The effect of aperture averaging is evaluated in all atmospheric turbulence conditions as well.

Posttest RELAP4 analysis of LOFT experiment L1-4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grush, W.H.; Holmstrom, H.L.O.

Results of posttest analysis of LOFT loss-of-coolant experiment L1-4 with the RELAP4 code are presented. The results are compared with the pretest prediction and the test data. Differences between the RELAP4 model used for this analysis and that used for the pretest prediction are in the areas of initial conditions, nodalization, emergency core cooling system, broken loop hot leg, and steam generator secondary. In general, these changes made only minor improvement in the comparison of the analytical results to the data. Also presented are the results of a limited study of LOFT downcomer modeling which compared the performance of themore » conventional single downcomer model with that of the new split downcomer model. A RELAP4 sensitivity calculation with artificially elevated emergency core coolant temperature was performed to highlight the need for an ECC mixing model in RELAP4.« less

Multiobjective Decision Making Policies and Coordination Mechanisms in Hierarchical Organizations: Results of an Agent-Based Simulation

PubMed Central

2014-01-01

This paper analyses how different coordination modes and different multiobjective decision making approaches interfere with each other in hierarchical organizations. The investigation is based on an agent-based simulation. We apply a modified NK-model in which we map multiobjective decision making as adaptive walk on multiple performance landscapes, whereby each landscape represents one objective. We find that the impact of the coordination mode on the performance and the speed of performance improvement is critically affected by the selected multiobjective decision making approach. In certain setups, the performances achieved with the more complex multiobjective decision making approaches turn out to be less sensitive to the coordination mode than the performances achieved with the less complex multiobjective decision making approaches. Furthermore, we present results on the impact of the nature of interactions among decisions on the achieved performance in multiobjective setups. Our results give guidance on how to control the performance contribution of objectives to overall performance and answer the question how effective certain multiobjective decision making approaches perform under certain circumstances (coordination mode and interdependencies among decisions). PMID:25152926

Presentation and outcome of clinical poor performance in one health district over a 5-year period: 2002–2007

PubMed Central

Cox, Stephen J; Holden, John D

2009-01-01

Background The detection, assessment, and management of primary care poor performance raise difficult issues for all those involved. Guidance has largely focused on managing the most serious cases where patient safety is severely compromised. The management of primary care poor performance has become an increasingly important part of primary care trust (PCT) work, but its modes of presentation and prevalence are not well known. Aim To report the prevalence, presentation modes, and management of primary care poor performance cases presenting to one PCT over a 5-year period. Design of study A retrospective review of primary care poor performance cases in one district. Setting St Helens PCT administered 35 practices with 130 GPs on the performers list, caring for 190 110 patients in North West England, UK. Method Cases presenting during 2002–2007 were initially reviewed by the chair of the PCT clinical executive committee. Anonymised data were then jointly reviewed by the assessor and another experienced GP advisor. Results There were 102 individual presentations (20 per year or one every 2–3 weeks) where clinician performance raised significant cause for concern occurred over the 5-year period. These concerns related to 37 individual clinicians, a range of 1–14 per clinician (mean 2.7). Whistleblowing by professional colleagues on 43 occasions was the most common presentation, of which 26 were from GPs about GPs. Patient complaints (18) were the second most common presentation. Twenty-seven clinicians were GPs, of whom the General Medical Council (GMC) were notified or involved in 13 cases. Clinicians were supported locally, and remedying was exclusively locally managed in 14 cases, and shared with an external organisation (such as the GMC or deanery) in another 12. Conclusion Professional whistleblowing and patient complaints were the most common sources of presentation. Effective PCT teams are needed to manage clinicians whose performance gives cause for concern. Sufficient resources and both formal and informal ways of reporting concerns are essential. PMID:19401017

Orbit Transfer Vehicle (OTV) engine, phase A study. Volume 2: Study

NASA Technical Reports Server (NTRS)

Mellish, J. A.

1979-01-01

The hydrogen oxygen engine used in the orbiter transfer vehicle is described. The engine design is analyzed and minimum engine performance and man rating requirements are discussed. Reliability and safety analysis test results are presented and payload, risk and cost, and engine installation parameters are defined. Engine tests were performed including performance analysis, structural analysis, thermal analysis, turbomachinery analysis, controls analysis, and cycle analysis.

Visual performance modeling in the human operator simulator

NASA Technical Reports Server (NTRS)

Strieb, M. I.

1979-01-01

A brief description of the history of the development of the human operator simulator (HOS) model is presented. Features of the HOS micromodels that impact on the obtainment of visual performance data are discussed along with preliminary details on a HOS pilot model designed to predict the results of visual performance workload data obtained through oculometer studies on pilots in real and simulated approaches and landings.

Study of target and non-target interplay in spatial attention task.

PubMed

Sweeti; Joshi, Deepak; Panigrahi, B K; Anand, Sneh; Santhosh, Jayasree

2018-02-01

Selective visual attention is the ability to selectively pay attention to the targets while inhibiting the distractors. This paper aims to study the targets and non-targets interplay in spatial attention task while subject attends to the target object present in one visual hemifield and ignores the distractor present in another visual hemifield. This paper performs the averaged evoked response potential (ERP) analysis and time-frequency analysis. ERP analysis agrees to the left hemisphere superiority over late potentials for the targets present in right visual hemifield. Time-frequency analysis performed suggests two parameters i.e. event-related spectral perturbation (ERSP) and inter-trial coherence (ITC). These parameters show the same properties for the target present in either of the visual hemifields but show the difference while comparing the activity corresponding to the targets and non-targets. In this way, this study helps to visualise the difference between targets present in the left and right visual hemifields and, also the targets and non-targets present in the left and right visual hemifields. These results could be utilised to monitor subjects' performance in brain-computer interface (BCI) and neurorehabilitation.

Performance-Based Funding in Public Schools.

ERIC Educational Resources Information Center

Foster, Charles A.; Marquart, Deanna J.

This report examines three performance-based funding (PBF) plans: (1) merit pay for teachers and/or administrators; (2) career ladders; and (3) formula-driven incentive payments to schools. The report contends that present-day problems in public schools result largely from the organizational structure of the educational enterprise. Being based on…

The Role of Learning Objectives under the Academic Big Top.

ERIC Educational Resources Information Center

Kelly, Leonard P.

1980-01-01

Likens a circus performer's varied responsibilities to the learning tasks required of undergraduates. Suggests that students' inability to perform many of these tasks results from confusion about instructors' expectations and the appropriateness of various learning strategies to different tasks. Recommends that students be presented with clear…

Is Low-Impact Aerobic Dance an Effective Cardiovascular Workout?

ERIC Educational Resources Information Center

Williford, Henry N.; And Others

1989-01-01

Presents results of an investigation comparing energy cost and cardiovascular responses of aerobic dance routines performed at different intensity levels in varying amounts of energy expenditure. For low-impact dance to meet minimum guidelines suggested by the American College of Sports Medicine, it should be performed at high intensity. (SM)