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Sample records for accuracy response time

  1. Speed-Accuracy Response Models: Scoring Rules Based on Response Time and Accuracy

    ERIC Educational Resources Information Center

    Maris, Gunter; van der Maas, Han

    2012-01-01

    Starting from an explicit scoring rule for time limit tasks incorporating both response time and accuracy, and a definite trade-off between speed and accuracy, a response model is derived. Since the scoring rule is interpreted as a sufficient statistic, the model belongs to the exponential family. The various marginal and conditional distributions…

  2. Distinguishing Fast and Slow Processes in Accuracy - Response Time Data.

    PubMed

    Coomans, Frederik; Hofman, Abe; Brinkhuis, Matthieu; van der Maas, Han L J; Maris, Gunter

    2016-01-01

    We investigate the relation between speed and accuracy within problem solving in its simplest non-trivial form. We consider tests with only two items and code the item responses in two binary variables: one indicating the response accuracy, and one indicating the response speed. Despite being a very basic setup, it enables us to study item pairs stemming from a broad range of domains such as basic arithmetic, first language learning, intelligence-related problems, and chess, with large numbers of observations for every pair of problems under consideration. We carry out a survey over a large number of such item pairs and compare three types of psychometric accuracy-response time models present in the literature: two 'one-process' models, the first of which models accuracy and response time as conditionally independent and the second of which models accuracy and response time as conditionally dependent, and a 'two-process' model which models accuracy contingent on response time. We find that the data clearly violates the restrictions imposed by both one-process models and requires additional complexity which is parsimoniously provided by the two-process model. We supplement our survey with an analysis of the erroneous responses for an example item pair and demonstrate that there are very significant differences between the types of errors in fast and slow responses. PMID:27167518

  3. Distinguishing Fast and Slow Processes in Accuracy - Response Time Data

    PubMed Central

    Coomans, Frederik; Hofman, Abe; Brinkhuis, Matthieu; van der Maas, Han L. J.; Maris, Gunter

    2016-01-01

    We investigate the relation between speed and accuracy within problem solving in its simplest non-trivial form. We consider tests with only two items and code the item responses in two binary variables: one indicating the response accuracy, and one indicating the response speed. Despite being a very basic setup, it enables us to study item pairs stemming from a broad range of domains such as basic arithmetic, first language learning, intelligence-related problems, and chess, with large numbers of observations for every pair of problems under consideration. We carry out a survey over a large number of such item pairs and compare three types of psychometric accuracy-response time models present in the literature: two ‘one-process’ models, the first of which models accuracy and response time as conditionally independent and the second of which models accuracy and response time as conditionally dependent, and a ‘two-process’ model which models accuracy contingent on response time. We find that the data clearly violates the restrictions imposed by both one-process models and requires additional complexity which is parsimoniously provided by the two-process model. We supplement our survey with an analysis of the erroneous responses for an example item pair and demonstrate that there are very significant differences between the types of errors in fast and slow responses. PMID:27167518

  4. Posterior Predictive Checks for Conditional Independence between Response Time and Accuracy

    ERIC Educational Resources Information Center

    Bolsinova, Maria; Tijmstra, Jesper

    2016-01-01

    Conditional independence (CI) between response time and response accuracy is a fundamental assumption of many joint models for time and accuracy used in educational measurement. In this study, posterior predictive checks (PPCs) are proposed for testing this assumption. These PPCs are based on three discrepancy measures reflecting different…

  5. The Effect of Intervention on Accuracy of Students' Responses and Reaction Times to Geometry Problems

    ERIC Educational Resources Information Center

    Babai, Reuven; Zilber, Hanna; Stavy, Ruth; Tirosh, Dina

    2010-01-01

    This study investigates the effect on student performance in drawing their attention to relevant task variables, focusing on accuracy of responses and reaction times. We chose this methodology in order to better understand how such interventions affect the reasoning process. The study employs a geometry task in which the irrelevant salient…

  6. Presentation and response timing accuracy in Adobe Flash and HTML5/JavaScript Web experiments.

    PubMed

    Reimers, Stian; Stewart, Neil

    2015-06-01

    Web-based research is becoming ubiquitous in the behavioral sciences, facilitated by convenient, readily available participant pools and relatively straightforward ways of running experiments: most recently, through the development of the HTML5 standard. Although in most studies participants give untimed responses, there is a growing interest in being able to record response times online. Existing data on the accuracy and cross-machine variability of online timing measures are limited, and generally they have compared behavioral data gathered on the Web with similar data gathered in the lab. For this article, we took a more direct approach, examining two ways of running experiments online-Adobe Flash and HTML5 with CSS3 and JavaScript-across 19 different computer systems. We used specialist hardware to measure stimulus display durations and to generate precise response times to visual stimuli in order to assess measurement accuracy, examining effects of duration, browser, and system-to-system variability (such as across different Windows versions), as well as effects of processing power and graphics capability. We found that (a) Flash and JavaScript's presentation and response time measurement accuracy are similar; (b) within-system variability is generally small, even in low-powered machines under high load; (c) the variability of measured response times across systems is somewhat larger; and (d) browser type and system hardware appear to have relatively small effects on measured response times. Modeling of the effects of this technical variability suggests that for most within- and between-subjects experiments, Flash and JavaScript can both be used to accurately detect differences in response times across conditions. Concerns are, however, noted about using some correlational or longitudinal designs online. PMID:24903687

  7. An accuracy-response time capacity assessment function that measures performance against standard parallel predictions.

    PubMed

    Townsend, James T; Altieri, Nicholas

    2012-07-01

    Measures of human efficiency under increases in mental workload or attentional limitations are vital in studying human perception, cognition, and action. Assays of efficiency as workload changes have typically been confined to either reaction times (RTs) or accuracy alone. Within the realm of RTs, a nonparametric measure called the workload capacity coefficient has been employed in many studies (Townsend & Nozawa, 1995). However, the contribution of correct versus incorrect responses has been unavailable in that context. A nonparametric statistic that is capable of simultaneously taking into account accuracy as well as RTs would be highly useful. This theoretical study develops such a tool for two important decisional stopping rules. Preliminary data from a simple visual identification study illustrate one potential application. PMID:22775497

  8. How task complexity and stimulus modality affect motor execution: target accuracy, response timing and hesitations.

    PubMed

    Parrington, Lucy; MacMahon, Clare; Ball, Kevin

    2015-01-01

    Elite sports players are characterized by the ability to produce successful outcomes while attending to changing environmental conditions. Few studies have assessed whether the perceptual environment affects motor skill execution. To test the effect of changing task complexity and stimulus conditions, the authors examined response times and target accuracy of 12 elite Australian football players using a passing-based laboratory test. Data were assessed using mixed modeling and chi-square analyses. No differences were found in target accuracy for changes in complexity or stimulus condition. Decision, movement and total disposal time increased with complexity and decision hesitations were greater when distractions were present. Decision, movement and disposal time were faster for auditory in comparison to visual signals, and when free to choose, players passed more frequently to auditory rather than visual targets. These results provide perspective on how basic motor control processes such as reaction and response to stimuli are influenced in a complex motor skill. Findings suggest auditory stimuli should be included in decision-making studies and may be an important part of a decision-training environment. PMID:25584721

  9. The Effects of Spatial Stimulus-Response Compatibility on Choice Time Production Accuracy and Variability

    ERIC Educational Resources Information Center

    Rakitin, Brian C.

    2005-01-01

    Five experiments examined the relations between timing and attention using a choice time production task in which the latency of a spatial choice response is matched to a target interval (3 or 5 s). Experiments 1 and 2 indicated that spatial stimulus-response incompatibility increased nonscalar timing variability without affecting timing accuracy…

  10. An Accuracy--Response Time Capacity Assessment Function that Measures Performance against Standard Parallel Predictions

    ERIC Educational Resources Information Center

    Townsend, James T.; Altieri, Nicholas

    2012-01-01

    Measures of human efficiency under increases in mental workload or attentional limitations are vital in studying human perception, cognition, and action. Assays of efficiency as workload changes have typically been confined to either reaction times (RTs) or accuracy alone. Within the realm of RTs, a nonparametric measure called the "workload…

  11. A Semiparametric Model for Jointly Analyzing Response Times and Accuracy in Computerized Testing

    ERIC Educational Resources Information Center

    Wang, Chun; Fan, Zhewen; Chang, Hua-Hua; Douglas, Jeffrey A.

    2013-01-01

    The item response times (RTs) collected from computerized testing represent an underutilized type of information about items and examinees. In addition to knowing the examinees' responses to each item, we can investigate the amount of time examinees spend on each item. Current models for RTs mainly focus on parametric models, which have the…

  12. Accuracy, precision and response time of consumer bimetal and digital thermometers for cooked ground beef patties and chicken breasts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three models each of consumer instant-read bimetal and digital thermometers were tested for accuracy, precision and response time compared to a calibrated thermocouple in cooked 80 percent and 90 percent lean ground beef patties and boneless and bone-in split chicken breasts. At the recommended inse...

  13. High accuracy time transfer synchronization

    NASA Technical Reports Server (NTRS)

    Wheeler, Paul J.; Koppang, Paul A.; Chalmers, David; Davis, Angela; Kubik, Anthony; Powell, William M.

    1995-01-01

    In July 1994, the U.S. Naval Observatory (USNO) Time Service System Engineering Division conducted a field test to establish a baseline accuracy for two-way satellite time transfer synchronization. Three Hewlett-Packard model 5071 high performance cesium frequency standards were transported from the USNO in Washington, DC to Los Angeles, California in the USNO's mobile earth station. Two-Way Satellite Time Transfer links between the mobile earth station and the USNO were conducted each day of the trip, using the Naval Research Laboratory(NRL) designed spread spectrum modem, built by Allen Osborne Associates(AOA). A Motorola six channel GPS receiver was used to track the location and altitude of the mobile earth station and to provide coordinates for calculating Sagnac corrections for the two-way measurements, and relativistic corrections for the cesium clocks. This paper will discuss the trip, the measurement systems used and the results from the data collected. We will show the accuracy of using two-way satellite time transfer for synchronization and the performance of the three HP 5071 cesium clocks in an operational environment.

  14. Effects of Age and Task Load on Drivers’ Response Accuracy and Reaction Time When Responding to Traffic Lights

    PubMed Central

    Salvia, Emilie; Petit, Claire; Champely, Stéphane; Chomette, René; Di Rienzo, Franck; Collet, Christian

    2016-01-01

    Due to population aging, elderly drivers represent an increasing proportion of car drivers. Yet, how aging alters sensorimotor functions and impacts driving safety remains poorly understood. This paper aimed at assessing to which extent elderly drivers are sensitive to various task loads and how this affects the reaction time (RT) in a driving context. Old and middle-aged people completed RT tasks which reproduced cognitive demands encountered while driving. Participants had to detect and respond to traffic lights or traffic light arrows as quickly as possible, under three experimental conditions of incremental difficulty. In both groups, we hypothesized that decision-making would be impacted by the number of cues to be processed. The first test was a simple measure of RT. The second and third tests were choice RT tasks requiring the processing of 3 and 5 cues, respectively. Responses were collected within a 2 s time-window. Otherwise, the trial was considered a no-response. In both groups, the data revealed that RT, error rate (incorrect answers), and no-response rate increased along with task difficulty. However, the middle-aged group outperformed the elderly group. The RT difference between the two groups increased drastically along with task difficulty. In the third test, the rate of no-response suggested that elderly drivers needed more than 2 s to process complex information and respond accurately. Both prolonged RT and increased no-response rate, especially for difficult tasks, might attest an impairment of cognitive abilities in relation to aging. Accordingly, casual driving conditions for young drivers may be particularly complex and stressful for elderly people who should thus be informed about the effects of normal aging upon driving. PMID:27462266

  15. Time and position accuracy using codeless GPS

    NASA Technical Reports Server (NTRS)

    Dunn, C. E.; Jefferson, D. C.; Lichten, S. M.; Thomas, J. B.; Vigue, Y.; Young, L. E.

    1994-01-01

    The Global Positioning System has allowed scientists and engineers to make measurements having accuracy far beyond the original 15 meter goal of the system. Using global networks of P-Code capable receivers and extensive post-processing, geodesists have achieved baseline precision of a few parts per billion, and clock offsets have been measured at the nanosecond level over intercontinental distances. A cloud hangs over this picture, however. The Department of Defense plans to encrypt the P-Code (called Anti-Spoofing, or AS) in the fall of 1993. After this event, geodetic and time measurements will have to be made using codeless GPS receivers. However, there appears to be a silver lining to the cloud. In response to the anticipated encryption of the P-Code, the geodetic and GPS receiver community has developed some remarkably effective means of coping with AS without classified information. We will discuss various codeless techniques currently available and the data noise resulting from each. We will review some geodetic results obtained using only codeless data, and discuss the implications for time measurements. Finally, we will present the status of GPS research at JPL in relation to codeless clock measurements.

  16. Accuracy metrics for judging time scale algorithms

    NASA Technical Reports Server (NTRS)

    Douglas, R. J.; Boulanger, J.-S.; Jacques, C.

    1994-01-01

    Time scales have been constructed in different ways to meet the many demands placed upon them for time accuracy, frequency accuracy, long-term stability, and robustness. Usually, no single time scale is optimum for all purposes. In the context of the impending availability of high-accuracy intermittently-operated cesium fountains, we reconsider the question of evaluating the accuracy of time scales which use an algorithm to span interruptions of the primary standard. We consider a broad class of calibration algorithms that can be evaluated and compared quantitatively for their accuracy in the presence of frequency drift and a full noise model (a mixture of white PM, flicker PM, white FM, flicker FM, and random walk FM noise). We present the analytic techniques for computing the standard uncertainty for the full noise model and this class of calibration algorithms. The simplest algorithm is evaluated to find the average-frequency uncertainty arising from the noise of the cesium fountain's local oscillator and from the noise of a hydrogen maser transfer-standard. This algorithm and known noise sources are shown to permit interlaboratory frequency transfer with a standard uncertainty of less than 10(exp -15) for periods of 30-100 days.

  17. Training in timing improves accuracy in golf.

    PubMed

    Libkuman, Terry M; Otani, Hajime; Steger, Neil

    2002-01-01

    In this experiment, the authors investigated the influence of training in timing on performance accuracy in golf. During pre- and posttesting, 40 participants hit golf balls with 4 different clubs in a golf course simulator. The dependent measure was the distance in feet that the ball ended from the target. Between the pre- and posttest, participants in the experimental condition received 10 hr of timing training with an instrument that was designed to train participants to tap their hands and feet in synchrony with target sounds. The participants in the control condition read literature about how to improve their golf swing. The results indicated that the participants in the experimental condition significantly improved their accuracy relative to the participants in the control condition, who did not show any improvement. We concluded that training in timing leads to improvement in accuracy, and that our results have implications for training in golf as well as other complex motor activities. PMID:12038497

  18. Accuracy, precision and response time of consumer fork, remote digital probe and disposable indicator thermometers for cooked ground beef patties and chicken breasts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nine different commercially available instant-read consumer thermometers (forks, remotes, digital probe and disposable color change indicators) were tested for accuracy and precision compared to a calibrated thermocouple in 80 percent and 90 percent lean ground beef patties, and boneless and bone-in...

  19. Lexical and Sub-Lexical Effects on Accuracy, Reaction Time and Response Duration: Impaired and Typical Word and Pseudoword Reading in a Transparent Orthography

    ERIC Educational Resources Information Center

    Davies, Robert; Rodriguez-Ferreiro, Javier; Suarez, Paz; Cuetos, Fernando

    2013-01-01

    In an opaque orthography like English, phonological coding errors are a prominent feature of dyslexia. In a transparent orthography like Spanish, reading difficulties are characterized by slower reading speed rather than reduced accuracy. In previous research, the reading speed deficit was revealed by asking children to read lists of words.…

  20. Speed accuracy trade-off under response deadlines

    PubMed Central

    Karşılar, Hakan; Simen, Patrick; Papadakis, Samantha; Balcı, Fuat

    2014-01-01

    Perceptual decision making has been successfully modeled as a process of evidence accumulation up to a threshold. In order to maximize the rewards earned for correct responses in tasks with response deadlines, participants should collapse decision thresholds dynamically during each trial so that a decision is reached before the deadline. This strategy ensures on-time responding, though at the cost of reduced accuracy, since slower decisions are based on lower thresholds and less net evidence later in a trial (compared to a constant threshold). Frazier and Yu (2008) showed that the normative rate of threshold reduction depends on deadline delays and on participants' uncertainty about these delays. Participants should start collapsing decision thresholds earlier when making decisions under shorter deadlines (for a given level of timing uncertainty) or when timing uncertainty is higher (for a given deadline). We tested these predictions using human participants in a random dot motion discrimination task. Each participant was tested in free-response, short deadline (800 ms), and long deadline conditions (1000 ms). Contrary to optimal-performance predictions, the resulting empirical function relating accuracy to response time (RT) in deadline conditions did not decline to chance level near the deadline; nor did the slight decline we typically observed relate to measures of endogenous timing uncertainty. Further, although this function did decline slightly with increasing RT, the decline was explainable by the best-fitting parameterization of Ratcliff's diffusion model (Ratcliff, 1978), whose parameters are constant within trials. Our findings suggest that at the very least, typical decision durations are too short for participants to adapt decision parameters within trials. PMID:25177265

  1. Acoustic environmental accuracy requirements for response determination

    NASA Technical Reports Server (NTRS)

    Pettitt, M. R.

    1983-01-01

    A general purpose computer program was developed for the prediction of vehicle interior noise. This program, named VIN, has both modal and statistical energy analysis capabilities for structural/acoustic interaction analysis. The analytic models and their computer implementation were verified through simple test cases with well-defined experimental results. The model was also applied in a space shuttle payload bay launch acoustics prediction study. The computer program processes large and small problems with equal efficiency because all arrays are dynamically sized by program input variables at run time. A data base is built and easily accessed for design studies. The data base significantly reduces the computational costs of such studies by allowing the reuse of the still-valid calculated parameters of previous iterations.

  2. Timing accuracy of the GEO 600 data acquisition system

    NASA Astrophysics Data System (ADS)

    Kötter, K.; Hewitson, M.; Ward, H.

    2004-03-01

    This paper describes the tests done for validating the timing accuracy of the GEO 600 data acquisition system. Correct time stamping of the recorded data is required for a number of search algorithms for gravitational wave signals (coincidence analysis, targeted pulsar searches, etc). Tests on the current system determined the absolute timing offset to be 15.89 µs with a standard deviation of 63 ns. Both offset and jitter were measured against an external reference clock. Additional analysis of data recorded during the S1 data taking run was done to validate the timing accuracy during this period.

  3. COMPASS time synchronization and dissemination—Toward centimetre positioning accuracy

    NASA Astrophysics Data System (ADS)

    Wang, ZhengBo; Zhao, Lu; Wang, ShiGuang; Zhang, JianWei; Wang, Bo; Wang, LiJun

    2014-09-01

    In this paper we investigate methods to achieve highly accurate time synchronization among the satellites of the COMPASS global navigation satellite system (GNSS). Owing to the special design of COMPASS which implements several geo-stationary satellites (GEO), time synchronization can be highly accurate via microwave links between ground stations to the GEO satellites. Serving as space-borne relay stations, the GEO satellites can further disseminate time and frequency signals to other satellites such as the inclined geo-synchronous (IGSO) and mid-earth orbit (MEO) satellites within the system. It is shown that, because of the accuracy in clock synchronization, the theoretical accuracy of COMPASS positioning and navigation will surpass that of the GPS. In addition, the COMPASS system can function with its entire positioning, navigation, and time-dissemination services even without the ground link, thus making it much more robust and secure. We further show that time dissemination using the COMPASS-GEO satellites to earth-fixed stations can achieve very high accuracy, to reach 100 ps in time dissemination and 3 cm in positioning accuracy, respectively. In this paper, we also analyze two feasible synchronization plans. All special and general relativistic effects related to COMPASS clocks frequency and time shifts are given. We conclude that COMPASS can reach centimeter-level positioning accuracy and discuss potential applications.

  4. Accuracy of Pedometer Steps and Time for Youth with Disabilities

    ERIC Educational Resources Information Center

    Beets, Michael W.; Combs, Cindy; Pitetti, Kenneth H.; Morgan, Melinda; Bryan, Rebecca R.; Foley, John T.

    2007-01-01

    The purpose of the study was to examine the accuracy of pedometer steps and activity time (Walk4Life, WL) for youth with developmental disabilities. Eighteen youth (11 girls, 7 boys) 4-14 years completed six 80-meter self-paced walking trials while wearing a pedometer at five waist locations (front right, front left, back right, back left, middle…

  5. A Measurement Model for Likert Responses that Incorporates Response Time

    ERIC Educational Resources Information Center

    Ferrando, Pere J.; Lorenzo-Seva, Urbano

    2007-01-01

    This article describes a model for response times that is proposed as a supplement to the usual factor-analytic model for responses to graded or more continuous typical-response items. The use of the proposed model together with the factor model provides additional information about the respondent and can potentially increase the accuracy of the…

  6. Improved time-domain accuracy standards for model gravitational waveforms

    SciTech Connect

    Lindblom, Lee; Baker, John G.

    2010-10-15

    Model gravitational waveforms must be accurate enough to be useful for detection of signals and measurement of their parameters, so appropriate accuracy standards are needed. Yet these standards should not be unnecessarily restrictive, making them impractical for the numerical and analytical modelers to meet. The work of Lindblom, Owen, and Brown [Phys. Rev. D 78, 124020 (2008)] is extended by deriving new waveform accuracy standards which are significantly less restrictive while still ensuring the quality needed for gravitational-wave data analysis. These new standards are formulated as bounds on certain norms of the time-domain waveform errors, which makes it possible to enforce them in situations where frequency-domain errors may be difficult or impossible to estimate reliably. These standards are less restrictive by about a factor of 20 than the previously published time-domain standards for detection, and up to a factor of 60 for measurement. These new standards should therefore be much easier to use effectively.

  7. Holter triage ambulatory ECG analysis. Accuracy and time efficiency.

    PubMed

    Cooper, D H; Kennedy, H L; Lyyski, D S; Sprague, M K

    1996-01-01

    Triage ambulatory electrocardiographic (ECG) analysis permits relatively unskilled office workers to submit 24-hour ambulatory ECG Holter tapes to an automatic instrument (model 563, Del Mar Avionics, Irvine, CA) for interpretation. The instrument system "triages" what it is capable of automatically interpreting and rejects those tapes (with high ventricular arrhythmia density) requiring thorough analysis. Nevertheless, a trained cardiovascular technician ultimately edits what is accepted for analysis. This study examined the clinical validity of one manufacturer's triage instrumentation with regard to accuracy and time efficiency for interpreting ventricular arrhythmia. A database of 50 Holter tapes stratified for frequency of ventricular ectopic beats (VEBs) was examined by triage, conventional, and full-disclosure hand-count Holter analysis. Half of the tapes were found to be automatically analyzable by the triage method. Comparison of the VEB accuracy of triage versus conventional analysis using the full-disclosure hand count as the standard showed that triage analysis overall appeared as accurate as conventional Holter analysis but had limitations in detecting ventricular tachycardia (VT) runs. Overall sensitivity, positive predictive accuracy, and false positive rate for the triage ambulatory ECG analysis were 96, 99, and 0.9%, respectively, for isolated VEBs, 92, 93, and 7%, respectively, for ventricular couplets, and 48, 93, and 7%, respectively, for VT. Error in VT detection by triage analysis occurred on a single tape. Of the remaining 11 tapes containing VT runs, accuracy was significantly increased, with a sensitivity of 86%, positive predictive accuracy of 90%, and false positive rate of 10%. Stopwatch-recorded time efficiency was carefully logged during both triage and conventional ambulatory ECG analysis and divided into five time phases: secretarial, machine, analysis, editing, and total time. Triage analysis was significantly (P < .05) more time

  8. Operating a real time high accuracy positioning system

    NASA Astrophysics Data System (ADS)

    Johnston, G.; Hanley, J.; Russell, D.; Vooght, A.

    2003-04-01

    The paper shall review the history and development of real time DGPS services prior to then describing the design of a high accuracy GPS commercial augmentation system and service currently delivering over a wide area to users of precise positioning products. The infrastructure and system shall be explained in relation to the need for high accuracy and high integrity of positioning for users. A comparison of the different techniques for the delivery of data shall be provided to outline the technical approach taken. Examples of the performance of the real time system shall be shown in various regions and modes to outline the current achievable accuracies. Having described and established the current GPS based situation, a review of the potential of the Galileo system shall be presented. Following brief contextual information relating to the Galileo project, core system and services, the paper will identify possible key applications and the main user communities for sub decimetre level precise positioning. The paper will address the Galileo and modernised GPS signals in space that are relevant to commercial precise positioning for the future and will discuss the implications for precise positioning performance. An outline of the proposed architecture shall be described and associated with pointers towards a successful implementation. Central to this discussion will be an assessment of the likely evolution of system infrastructure and user equipment implementation, prospects for new applications and their effect upon the business case for precise positioning services.

  9. Accuracy-based time step criteria for solving parabolic equations

    SciTech Connect

    Mohtar, R.; Segerlind, L.

    1995-12-31

    Parabolic equations govern many transient engineering problems. Space integration using finite element or finite difference methods changes the parabolic partial differential equation into an ordinary differential equation. Time integration schemes are needed to solve the later equation. In order to accurately perform the later integration a proper time step must be provided. Time step estimates based on a stability criteria have been prescribed in the literature. The following paper presents time step estimates that satisfy stability as well as accuracy criteria. These estimates were correlated to the Froude and Courant Numbers. The later criteria were found to be overly conservative for some integration schemes. Suggestions as to which time integration scheme is the best to use are also presented.

  10. Improving Adaptive Learning Technology through the Use of Response Times

    ERIC Educational Resources Information Center

    Mettler, Everett; Massey, Christine M.; Kellman, Philip J.

    2011-01-01

    Adaptive learning techniques have typically scheduled practice using learners' accuracy and item presentation history. We describe an adaptive learning system (Adaptive Response Time Based Sequencing--ARTS) that uses both accuracy and response time (RT) as direct inputs into sequencing. Response times are used to assess learning strength and…

  11. Assessing expected accuracy of probe vehicle travel time reports

    SciTech Connect

    Hellinga, B.; Fu, L.

    1999-12-01

    The use of probe vehicles to provide estimates of link travel times has been suggested as a means of obtaining travel times within signalized networks for use in advanced travel information systems. Past research in the literature has proved contradictory conclusions regarding the expected accuracy of these probe-based estimates, and consequently has estimated different levels of market penetration of probe vehicles required to sustain accurate data within an advanced traveler information system. This paper examines the effect of sampling bias on the accuracy of the probe estimates. An analytical expression is derived on the basis of queuing theory to prove that bias in arrival time distributions and/or in the proportion of probes associated with each link departure turning movement will lead to a systematic bias in the sample estimate of the mean delay. Subsequently, the potential for and impact of sampling bias on a signalized link is examined by simulating an arterial corridor. The analytical derivation and the simulation analysis show that the reliability of probe-based average link travel times is highly affected by sampling bias. Furthermore, this analysis shows that the contradictory conclusions of previous research are directly related to the presence of absence of sample bias.

  12. Accuracy of real time radiography burning rate measurement

    NASA Astrophysics Data System (ADS)

    Olaniyi, Bisola

    The design of a solid propellant rocket motor requires the determination of a propellant's burning-rate and its dependency upon environmental parameters. The requirement that the burning-rate be physically measured, establishes the need for methods and equipment to obtain such data. A literature review reveals that no measurement has provided the desired burning rate accuracy. In the current study, flash x-ray modeling and digitized film-density data were employed to predict motor-port area to length ratio. The pre-fired port-areas and base burning rate were within 2.5% and 1.2% of their known values, respectively. To verify the accuracy of the method, a continuous x-ray and a solid propellant rocket motor model (Plexiglas cylinder) were used. The solid propellant motor model was translated laterally through a real-time radiography system at different speeds simulating different burning rates. X-ray images were captured and the burning-rate was then determined. The measured burning rate was within 1.65% of the known values.

  13. Dichotomy in perceptual learning of interval timing: calibration of mean accuracy and precision differ in specificity and time course.

    PubMed

    Sohn, Hansem; Lee, Sang-Hun

    2013-01-01

    Our brain is inexorably confronted with a dynamic environment in which it has to fine-tune spatiotemporal representations of incoming sensory stimuli and commit to a decision accordingly. Among those representations needing constant calibration is interval timing, which plays a pivotal role in various cognitive and motor tasks. To investigate how perceived time interval is adjusted by experience, we conducted a human psychophysical experiment using an implicit interval-timing task in which observers responded to an invisible bar drifting at a constant speed. We tracked daily changes in distributions of response times for a range of physical time intervals over multiple days of training with two major types of timing performance, mean accuracy and precision. We found a decoupled dynamics of mean accuracy and precision in terms of their time course and specificity of perceptual learning. Mean accuracy showed feedback-driven instantaneous calibration evidenced by a partial transfer around the time interval trained with feedback, while timing precision exhibited a long-term slow improvement with no evident specificity. We found that a Bayesian observer model, in which a subjective time interval is determined jointly by a prior and likelihood function for timing, captures the dissociative temporal dynamics of the two types of timing measures simultaneously. Finally, the model suggested that the width of the prior, not the likelihoods, gradually shrinks over sessions, substantiating the important role of prior knowledge in perceptual learning of interval timing. PMID:23076112

  14. Time-resolved spectral imaging: better photon economy, higher accuracy

    NASA Astrophysics Data System (ADS)

    Fereidouni, Farzad; Reitsma, Keimpe; Blab, Gerhard A.; Gerritsen, Hans C.

    2015-03-01

    Lifetime and spectral imaging are complementary techniques that offer a non-invasive solution for monitoring metabolic processes, identifying biochemical compounds, and characterizing their interactions in biological tissues, among other tasks. Newly developed instruments that perform time-resolved spectral imaging can provide even more information and reach higher sensitivity than either modality alone. Here we report a multispectral lifetime imaging system based on a field-programmable gate array (FPGA), capable of operating at high photon count rates (12 MHz) per spectral detection channel, and with time resolution of 200 ps. We performed error analyses to investigate the effect of gate width and spectral-channel width on the accuracy of estimated lifetimes and spectral widths. Temporal and spectral phasors were used for analysis of recorded data, and we demonstrated blind un-mixing of the fluorescent components using information from both modalities. Fractional intensities, spectra, and decay curves of components were extracted without need for prior information. We further tested this approach with fluorescently doubly-labeled DNA, and demonstrated its suitability for accurately estimating FRET efficiency in the presence of either non-interacting or interacting donor molecules.

  15. Inertial Measures of Motion for Clinical Biomechanics: Comparative Assessment of Accuracy under Controlled Conditions – Changes in Accuracy over Time

    PubMed Central

    Lebel, Karina; Boissy, Patrick; Hamel, Mathieu; Duval, Christian

    2015-01-01

    Background Interest in 3D inertial motion tracking devices (AHRS) has been growing rapidly among the biomechanical community. Although the convenience of such tracking devices seems to open a whole new world of possibilities for evaluation in clinical biomechanics, its limitations haven’t been extensively documented. The objectives of this study are: 1) to assess the change in absolute and relative accuracy of multiple units of 3 commercially available AHRS over time; and 2) to identify different sources of errors affecting AHRS accuracy and to document how they may affect the measurements over time. Methods This study used an instrumented Gimbal table on which AHRS modules were carefully attached and put through a series of velocity-controlled sustained motions including 2 minutes motion trials (2MT) and 12 minutes multiple dynamic phases motion trials (12MDP). Absolute accuracy was assessed by comparison of the AHRS orientation measurements to those of an optical gold standard. Relative accuracy was evaluated using the variation in relative orientation between modules during the trials. Findings Both absolute and relative accuracy decreased over time during 2MT. 12MDP trials showed a significant decrease in accuracy over multiple phases, but accuracy could be enhanced significantly by resetting the reference point and/or compensating for initial Inertial frame estimation reference for each phase. Interpretation The variation in AHRS accuracy observed between the different systems and with time can be attributed in part to the dynamic estimation error, but also and foremost, to the ability of AHRS units to locate the same Inertial frame. Conclusions Mean accuracies obtained under the Gimbal table sustained conditions of motion suggest that AHRS are promising tools for clinical mobility assessment under constrained conditions of use. However, improvement in magnetic compensation and alignment between AHRS modules are desirable in order for AHRS to reach their

  16. Diagnostic accuracy of the bronchodilator response in children

    PubMed Central

    Tse, Sze Man; Gold, Diane R.; Sordillo, Joanne E.; Hoffman, Elaine B.; Gillman, Matthew W.; Rifas-Shiman, Sheryl L.; Fuhlbrigge, Anne L.; Tantisira, Kelan G.; Weiss, Scott T.; Litonjua, Augusto A.

    2013-01-01

    Background The bronchodilator response (BDR) reflects the reversibility of airflow obstruction and is recommended as an adjunctive test to diagnose asthma. The validity of the commonly used definition of BDR, a 12% or greater change in FEV1 from baseline, has been questioned in childhood. Objectives We sought to examine the diagnostic accuracy of the BDR test by using 3 large pediatric cohorts. Methods Cases include 1041 children with mild-to-moderate asthma from the Childhood Asthma Management Program. Control subjects (nonasthmatic and nonwheezing) were chosen from Project Viva and Home Allergens, 2 population-based pediatric cohorts. Receiver operating characteristic curves were constructed, and areas under the curve were calculated for different BDR cutoffs. Results A total of 1041 cases (59.7% male; mean age, 8.9 ± 2.1 years) and 250 control subjects (46.8% male; mean age, 8.7 ± 1.7 years) were analyzed, with mean BDRs of 10.7% ± 10.2% and 2.7% ± 8.4%, respectively. The BDR test differentiated asthmatic patients from nonasthmatic patients with a moderate accuracy (area under the curve, 73.3%). Despite good specificity, a cutoff of 12% was associated with poor sensitivity (35.6%). A cutoff of less than 8% performed significantly better than a cutoff of 12% (P = .03, 8% vs 12%). Conclusions Our findings highlight the poor sensitivity associated with the commonly used 12% cutoff for BDR. Although our data show that a threshold of less than 8% performs better than 12%, given the variability of this test in children, we conclude that it might be not be appropriate to choose a specific BDR cutoff as a criterion for the diagnosis of asthma. PMID:23683464

  17. Response times to conceptual questions

    NASA Astrophysics Data System (ADS)

    Lasry, Nathaniel; Watkins, Jessica; Mazur, Eric; Ibrahim, Ahmed

    2013-09-01

    We measured the time taken by students to respond to individual Force Concept Inventory (FCI) questions. We examine response time differences between correct and incorrect answers, both before and after instruction. We also determine the relation between response time and expressed confidence. Our data reveal three results of interest. First, response times are longer for incorrect answers than for correct ones, indicating that distractors are not automatic choices. Second, response times increase after instruction for both correct and incorrect answers, supporting the notion that instruction changes students' approach to conceptual questions. Third, response times are inversely related to students' expressed confidence; the lower their confidence, the longer it takes to respond.

  18. Modeling Response Signal and Response Time Data

    ERIC Educational Resources Information Center

    Ratcliff, Roger

    2006-01-01

    The diffusion model (Ratcliff, 1978) and the leaky competing accumulator model (LCA, Usher & McClelland, 2001) were tested against two-choice data collected from the same subjects with the standard response time procedure and the response signal procedure. In the response signal procedure, a stimulus is presented and then, at one of a number of…

  19. Response time of internauts

    NASA Astrophysics Data System (ADS)

    Johansen, Anders

    2001-07-01

    A new experiment measuring the dynamical response of the Internet population to a “point-like” perturbation has been performed. The nature of the perturbation was that of an announcement, specifically a web-interview on stock market crashes, which contained the URL to the author's articles on the subject. It was established that the download rate obeys the relation ≈1/ t in qualitative agreement with previously reported results.

  20. Nerve conduction velocity measurements: improved accuracy using superimposed response waves.

    PubMed

    Halar, E M; Venkatesh, B

    1976-10-01

    A new procedure of serial motor nerve conduction velocity (NCV) measurements with the use of "superimposed response waves" technique (or double stimulus technique) was performed on 29 normal subjects. Six peripheral nerves were tested once a week for four to six weeks. A total of 760 NCV measurements were thus obtained to try to assess the magnitude of error in serial NCV testings. With the double stimulus technique employed, a significant reduction in variations of serial NCV measurements was found. The overall standard deviation of four to six consecutive NCV measurements in the 34 subjects was 1.3 meters per second with a coefficient of variation of 2.4%. These findings obtained with the double stimulus technique have proven to be approximately three times more accurate than results obtained by investigators who studied nerve conduction velocity measurement variation with single stimulus standard NCV testing techniques. PMID:184754

  1. Advantages of improved timing accuracy in PET cameras using LSOscintillator

    SciTech Connect

    Moses, William W.

    2002-12-02

    PET scanners based on LSO have the potential forsignificantly better coincidence timing resolution than the 6 ns fwhmtypically achieved with BGO. This study analyzes the performanceenhancements made possible by improved timing as a function of thecoincidence time resolution. If 500 ps fwhm coincidence timing resolutioncan be achieved in a complete PET camera, the following four benefits canbe realized for whole-body FDG imaging: 1) The random event rate can bereduced by using a narrower coincidence timing window, increasing thepeak NECR by~;50 percent. 2) Using time-of-flight in the reconstructionalgorithm will reduce the noise variance by a factor of 5. 3) Emissionand transmission data can be acquired simultaneously, reducing the totalscan time. 4) Axial blurring can be reduced by using time-of-flight todetermine the correct axial plane that each event originated from. Whiletime-of-flight was extensively studied in the 1980's, practical factorslimited its effectiveness at that time and little attention has been paidto timing in PET since then. As these potential improvements aresubstantial and the advent of LSO PET cameras gives us the means toobtain them without other sacrifices, efforts to improve PET timingshould resume after their long dormancy.

  2. Effects of Interviewer Behavior on Accuracy of Children's Responses

    ERIC Educational Resources Information Center

    Sparling, Jessica; Wilder, David A.; Kondash, Jennifer; Boyle, Megan; Compton, Megan

    2011-01-01

    Previous research has shown that certain interviewer behaviors can evoke inaccurate answers by children. In the current study, we examined the effects of approving and disapproving statements on the accuracy of 3 children's answers to questions in an interview (Experiment 1). We then evaluated 3 questioning techniques that may be used by…

  3. An Evaluation of Item Response Theory Classification Accuracy and Consistency Indices

    ERIC Educational Resources Information Center

    Wyse, Adam E.; Hao, Shiqi

    2012-01-01

    This article introduces two new classification consistency indices that can be used when item response theory (IRT) models have been applied. The new indices are shown to be related to Rudner's classification accuracy index and Guo's classification accuracy index. The Rudner- and Guo-based classification accuracy and consistency indices are…

  4. Attention: Reaction Time and Accuracy Reveal Different Mechanisms

    ERIC Educational Resources Information Center

    Prinzmetal, William; McCool, Christin; Park, Samuel

    2005-01-01

    The authors propose that there are 2 different mechanisms whereby spatial cues capture attention. The voluntary mechanism is the strategic allocation of perceptual resources to the location most likely to contain the target. The involuntary mechanism is a reflexive orienting response that occurs even when the spatial cue does not indicate the…

  5. An accuracy assessment of realtime GNSS time series toward semi- real time seafloor geodetic observation

    NASA Astrophysics Data System (ADS)

    Osada, Y.; Ohta, Y.; Demachi, T.; Kido, M.; Fujimoto, H.; Azuma, R.; Hino, R.

    2013-12-01

    Large interplate earthquake repeatedly occurred in Japan Trench. Recently, the detail crustal deformation revealed by the nation-wide inland GPS network called as GEONET by GSI. However, the maximum displacement region for interplate earthquake is mainly located offshore region. GPS/Acoustic seafloor geodetic observation (hereafter GPS/A) is quite important and useful for understanding of shallower part of the interplate coupling between subducting and overriding plates. We typically conduct GPS/A in specific ocean area based on repeated campaign style using research vessel or buoy. Therefore, we cannot monitor the temporal variation of seafloor crustal deformation in real time. The one of technical issue on real time observation is kinematic GPS analysis because kinematic GPS analysis based on reference and rover data. If the precise kinematic GPS analysis will be possible in the offshore region, it should be promising method for real time GPS/A with USV (Unmanned Surface Vehicle) and a moored buoy. We assessed stability, precision and accuracy of StarFireTM global satellites based augmentation system. We primarily tested for StarFire in the static condition. In order to assess coordinate precision and accuracy, we compared 1Hz StarFire time series and post-processed precise point positioning (PPP) 1Hz time series by GIPSY-OASIS II processing software Ver. 6.1.2 with three difference product types (ultra-rapid, rapid, and final orbits). We also used difference interval clock information (30 and 300 seconds) for the post-processed PPP processing. The standard deviation of real time StarFire time series is less than 30 mm (horizontal components) and 60 mm (vertical component) based on 1 month continuous processing. We also assessed noise spectrum of the estimated time series by StarFire and post-processed GIPSY PPP results. We found that the noise spectrum of StarFire time series is similar pattern with GIPSY-OASIS II processing result based on JPL rapid orbit

  6. Accuracy in Recalling Interest Inventory Information at Three Time Intervals

    ERIC Educational Resources Information Center

    Swanson, Jane L.; Gore, Paul A., Jr.; Leuwerke, Wade; D'Achiardi, Catalina; Edwards, Jorie Hitch; Edwards, Jared

    2006-01-01

    Rates of accurate recall of the Strong Interest Inventory (SII; L. W. Harmon, J. C. Hansen, F. H. Borgen, & A. L. Hammer, 1994) profile information varied with the amount of time elapsed since the interpretation, the type of SII scale, and whether immediate recall was elicited, but rates did not vary with the strategy used to provide the…

  7. Are Unshifted Distributional Models Appropriate for Response Time?

    ERIC Educational Resources Information Center

    Rouder, Jeffrey N.

    2005-01-01

    Van Breukelen (this issue) provides an approach to using both response time (RT) and accuracy for (1) measuring latent abilities of participants even when they may trade speed for accuracy, and for (2) providing insight into the psychological processes underlying task performance. In this commentary, I focus on the second of these aims and assess…

  8. Real-time lens distortion correction: speed, accuracy and efficiency

    NASA Astrophysics Data System (ADS)

    Bax, Michael R.; Shahidi, Ramin

    2014-11-01

    Optical lens systems suffer from nonlinear geometrical distortion. Optical imaging applications such as image-enhanced endoscopy and image-based bronchoscope tracking require correction of this distortion for accurate localization, tracking, registration, and measurement of image features. Real-time capability is desirable for interactive systems and live video. The use of a texture-mapping graphics accelerator, which is standard hardware on current motherboard chipsets and add-in video graphics cards, to perform distortion correction is proposed. Mesh generation for image tessellation, an error analysis, and performance results are presented. It is shown that distortion correction using commodity graphics hardware is substantially faster than using the main processor and can be performed at video frame rates (faster than 30 frames per second), and that the polar-based method of mesh generation proposed here is more accurate than a conventional grid-based approach. Using graphics hardware to perform distortion correction is not only fast and accurate but also efficient as it frees the main processor for other tasks, which is an important issue in some real-time applications.

  9. The accuracy of telling time via oscillatory signals

    NASA Astrophysics Data System (ADS)

    Monti, Michele; Rein ten Wolde, Pieter

    2016-06-01

    Circadian clocks are the central timekeepers of life, allowing cells to anticipate changes between day and night. Experiments in recent years have revealed that circadian clocks can be highly stable, raising the question how reliably they can be read out. Here, we combine mathematical modeling with information theory to address the question how accurately a cell can infer the time from an ensemble of protein oscillations, which are driven by a circadian clock. We show that the precision increases with the number of oscillations and their amplitude relative to their noise. Our analysis also reveals that their exists an optimal phase relation that minimizes the error in the estimate of time, which depends on the relative noise levels of the protein oscillations. Lastly, our work shows that cross-correlations in the noise of the protein oscillations can enhance the mutual information, which suggests that cross-regulatory interactions between the proteins that read out the clock can be beneficial for temporal information transmission.

  10. The accuracy of telling time via oscillatory signals.

    PubMed

    Monti, Michele; Wolde, Pieter Rein Ten

    2016-01-01

    Circadian clocks are the central timekeepers of life, allowing cells to anticipate changes between day and night. Experiments in recent years have revealed that circadian clocks can be highly stable, raising the question how reliably they can be read out. Here, we combine mathematical modeling with information theory to address the question how accurately a cell can infer the time from an ensemble of protein oscillations, which are driven by a circadian clock. We show that the precision increases with the number of oscillations and their amplitude relative to their noise. Our analysis also reveals that their exists an optimal phase relation that minimizes the error in the estimate of time, which depends on the relative noise levels of the protein oscillations. Lastly, our work shows that cross-correlations in the noise of the protein oscillations can enhance the mutual information, which suggests that cross-regulatory interactions between the proteins that read out the clock can be beneficial for temporal information transmission. PMID:27203353

  11. A Joint Modeling Approach for Reaction Time and Accuracy in Psycholinguistic Experiments

    ERIC Educational Resources Information Center

    Loeys, T.; Rosseel, Y.; Baten, K.

    2011-01-01

    In the psycholinguistic literature, reaction times and accuracy can be analyzed separately using mixed (logistic) effects models with crossed random effects for item and subject. Given the potential correlation between these two outcomes, a joint model for the reaction time and accuracy may provide further insight. In this paper, a Bayesian…

  12. Effects of interviewer behavior on accuracy of children's responses.

    PubMed

    Sparling, Jessica; Wilder, David A; Kondash, Jennifer; Boyle, Megan; Compton, Megan

    2011-01-01

    Previous research has shown that certain interviewer behaviors can evoke inaccurate answers by children. In the current study, we examined the effects of approving and disapproving statements on the accuracy of 3 children's answers to questions in an interview (Experiment 1). We then evaluated 3 questioning techniques that may be used by interviewers during a forensic interview in which a child provides eyewitness testimony (Experiment 2). All participants responded with more inaccurate answers when approving statements followed inaccurate information and disapproving statements followed accurate information in Experiment 1. During Experiment 2, 1 participant responded most inaccurately when she was requestioned after providing an initial answer, whereas the remaining 2 participants responded most inaccurately when the interviewer provided cowitness information and suggestive questions. PMID:21941387

  13. EFFECTS OF INTERVIEWER BEHAVIOR ON ACCURACY OF CHILDREN'S RESPONSES

    PubMed Central

    Sparling, Jessica; Wilder, David A; Kondash, Jennifer; Boyle, Megan; Compton, Megan

    2011-01-01

    Previous research has shown that certain interviewer behaviors can evoke inaccurate answers by children. In the current study, we examined the effects of approving and disapproving statements on the accuracy of 3 children's answers to questions in an interview (Experiment 1). We then evaluated 3 questioning techniques that may be used by interviewers during a forensic interview in which a child provides eyewitness testimony (Experiment 2). All participants responded with more inaccurate answers when approving statements followed inaccurate information and disapproving statements followed accurate information in Experiment 1. During Experiment 2, 1 participant responded most inaccurately when she was requestioned after providing an initial answer, whereas the remaining 2 participants responded most inaccurately when the interviewer provided cowitness information and suggestive questions. PMID:21941387

  14. On the Locus of Speed-Accuracy Trade-Off in Reaction Time: Inferences From the Lateralized Readiness Potential

    ERIC Educational Resources Information Center

    Rinkenauer, Gerhard; Osman, Allen; Ulrich, Rolf; Muller-Gethmann, Hiltraut; Mattes, Stefan

    2004-01-01

    Lateralized readiness potentials (LRPs) were used to determine the stage(s) of reaction time (RT) responsible for speed-accuracy trade-offs (SATs). Speeded decisions based on several types of information were examined in 3 experiments, involving, respectively, a line discrimination task, lexical decisions, and an Erikson flanker task. Three levels…

  15. Effects of shortened acquisition time on accuracy and precision of quantitative estimates of organ activity1

    PubMed Central

    He, Bin; Frey, Eric C.

    2010-01-01

    Purpose: Quantitative estimation of in vivo organ uptake is an essential part of treatment planning for targeted radionuclide therapy. This usually involves the use of planar or SPECT scans with acquisition times chosen based more on image quality considerations rather than the minimum needed for precise quantification. In previous simulation studies at clinical count levels (185 MBq 111In), the authors observed larger variations in accuracy of organ activity estimates resulting from anatomical and uptake differences than statistical noise. This suggests that it is possible to reduce the acquisition time without substantially increasing the variation in accuracy. Methods: To test this hypothesis, the authors compared the accuracy and variation in accuracy of organ activity estimates obtained from planar and SPECT scans at various count levels. A simulated phantom population with realistic variations in anatomy and biodistribution was used to model variability in a patient population. Planar and SPECT projections were simulated using previously validated Monte Carlo simulation tools. The authors simulated the projections at count levels approximately corresponding to 1.5–30 min of total acquisition time. The projections were processed using previously described quantitative SPECT (QSPECT) and planar (QPlanar) methods. The QSPECT method was based on the OS-EM algorithm with compensations for attenuation, scatter, and collimator-detector response. The QPlanar method is based on the ML-EM algorithm using the same model-based compensation for all the image degrading effects as the QSPECT method. The volumes of interests (VOIs) were defined based on the true organ configuration in the phantoms. The errors in organ activity estimates from different count levels and processing methods were compared in terms of mean and standard deviation over the simulated phantom population. Results: There was little degradation in quantitative reliability when the acquisition time was

  16. Verification of concentration time formulae accuracy in Southern Brazil

    NASA Astrophysics Data System (ADS)

    Freitas Ferreira, Pedro; Allasia, Daniel; Herbstrith Froemming, Gabriel; Ribeiro Fontoura, Jessica; Tassi, Rutineia

    2016-04-01

    The time of concentration (TC) of an urban catchment is a fundamental watershed parameter used to compute the peak discharge and/or in the hydrological simulation of sewer systems. In the lack of hydrological data for its estimative, several empirical formulae are used, however, almost none of them have been verified in Brazil leading to large uncertainties in the correct value. In this light, were tested several formulae such as the proposed by Kirpich (and a modifications of this equation proposed by the National Transport Bureau of Brazil (DNIT)), U.S. Corps. Of Engineers, Pasini, Dooge , Johnstone , Ventura and Ven T Chow as they are used in Brazil. The verification was accomplished against measured data in 5 sub-basins situated in the Dilúvio basin, a semi urbanized watershed that contains the most developed area of the city of Porto Alegre. All the rainfall stations were active in the period from late 1970's until early 1980's due to the existence of Projeto Dilúvio but today, however, only two of them are still in operation. Porto Alegre is the capital and largest city in the Brazilian southernmost state of Rio Grande do Sul with a population of approximately 1.6 million inhabitants, the tenth most populous city in the country and the centre of Brazil's fourth largest metropolitan area, with almost 4,5 million inhabitants (IBGE, 2010). The city is situated in a humid subtropical climate with high and regular precipitation throughout the year. Most summer rainfall occurs during thunderstorms and an occasional tropical storm, hurricane or cyclone. The results showed an error of around 70% for half of the formulas, with a tendency to underestimate TC values. Among the tested methods, Johnstone had the best overall result, with an average error of 25%, well far from the second, Dooge, with 43% of average error. The best results were obtained in only one basin, Dilúvio, the largest one, with an area of 25km², with an error of just 3% for Modified Kirpich, and

  17. Estimation Accuracy on Execution Time of Run-Time Tasks in a Heterogeneous Distributed Environment.

    PubMed

    Liu, Qi; Cai, Weidong; Jin, Dandan; Shen, Jian; Fu, Zhangjie; Liu, Xiaodong; Linge, Nigel

    2016-01-01

    Distributed Computing has achieved tremendous development since cloud computing was proposed in 2006, and played a vital role promoting rapid growth of data collecting and analysis models, e.g., Internet of things, Cyber-Physical Systems, Big Data Analytics, etc. Hadoop has become a data convergence platform for sensor networks. As one of the core components, MapReduce facilitates allocating, processing and mining of collected large-scale data, where speculative execution strategies help solve straggler problems. However, there is still no efficient solution for accurate estimation on execution time of run-time tasks, which can affect task allocation and distribution in MapReduce. In this paper, task execution data have been collected and employed for the estimation. A two-phase regression (TPR) method is proposed to predict the finishing time of each task accurately. Detailed data of each task have drawn interests with detailed analysis report being made. According to the results, the prediction accuracy of concurrent tasks' execution time can be improved, in particular for some regular jobs. PMID:27589753

  18. Cued Speech Transliteration: Effects of Speaking Rate and Lag Time on Production Accuracy.

    PubMed

    Krause, Jean C; Tessler, Morgan P

    2016-10-01

    Many deaf and hard-of-hearing children rely on interpreters to access classroom communication. Although the exact level of access provided by interpreters in these settings is unknown, it is likely to depend heavily on interpreter accuracy (portion of message correctly produced by the interpreter) and the factors that govern interpreter accuracy. In this study, the accuracy of 12 Cued Speech (CS) transliterators with varying degrees of experience was examined at three different speaking rates (slow, normal, fast). Accuracy was measured with a high-resolution, objective metric in order to facilitate quantitative analyses of the effect of each factor on accuracy. Results showed that speaking rate had a large negative effect on accuracy, caused primarily by an increase in omitted cues, whereas the effect of lag time on accuracy, also negative, was quite small and explained just 3% of the variance. Increased experience level was generally associated with increased accuracy; however, high levels of experience did not guarantee high levels of accuracy. Finally, the overall accuracy of the 12 transliterators, 54% on average across all three factors, was low enough to raise serious concerns about the quality of CS transliteration services that (at least some) children receive in educational settings. PMID:27221370

  19. Accuracy, security, and processing time comparisons of biometric fingerprint recognition system using digital and optical enhancements

    NASA Astrophysics Data System (ADS)

    Alsharif, Salim; El-Saba, Aed; Jagapathi, Rajendarreddy

    2011-06-01

    Fingerprint recognition is one of the most commonly used forms of biometrics and has been widely used in daily life due to its feasibility, distinctiveness, permanence, accuracy, reliability, and acceptability. Besides cost, issues related to accuracy, security, and processing time in practical biometric recognition systems represent the most critical factors that makes these systems widely acceptable. Accurate and secure biometric systems often require sophisticated enhancement and encoding techniques that burdens the overall processing time of the system. In this paper we present a comparison between common digital and optical enhancementencoding techniques with respect to their accuracy, security and processing time, when applied to biometric fingerprint systems.

  20. High-accuracy global time and frequency transfer with a space-borne hydrogen maser clock

    NASA Technical Reports Server (NTRS)

    Decher, R.; Allan, D. W.; Alley, C. O.; Baugher, C.; Duncan, B. J.; Vessot, R. F. C.; Winkler, G. M. R.

    1983-01-01

    A proposed system for high-accuracy global time and frequency transfer using a hydrogen maser clock in a space vehicle is discussed. Direct frequency transfer with a accuracy of 10 to the minus 14th power and time transfer with an estimated accuracy of 1 nsec are provided by a 3-link microwave system. A short pulse laser system is included for subnanosecond time transfer and system calibration. The results of studies including operational aspects, error sources, data flow, system configuration, and implementation requirements for an initial demonstration experiment using the Space Shuttle are discussed.

  1. Understanding less than nothing: children's neural response to negative numbers shifts across age and accuracy

    PubMed Central

    Gullick, Margaret M.; Wolford, George

    2013-01-01

    We examined the brain activity underlying the development of our understanding of negative numbers, which are amounts lacking direct physical counterparts. Children performed a paired comparison task with positive and negative numbers during an fMRI session. As previously shown in adults, both pre-instruction fifth-graders and post-instruction seventh-graders demonstrated typical behavioral and neural distance effects to negative numbers, where response times and parietal and frontal activity increased as comparison distance decreased. We then determined the factors impacting the distance effect in each age group. Behaviorally, the fifth-grader distance effect for negatives was significantly predicted only by positive comparison accuracy, indicating that children who were generally better at working with numbers were better at comparing negatives. In seventh-graders, negative number comparison accuracy significantly predicted their negative number distance effect, indicating that children who were better at working with negative numbers demonstrated a more typical distance effect. Across children, as age increased, the negative number distance effect increased in the bilateral IPS and decreased frontally, indicating a frontoparietal shift consistent with previous numerical development literature. In contrast, as negative comparison task accuracy increased, the parietal distance effect increased in the left IPS and decreased in the right, possibly indicating a change from an approximate understanding of negatives' values to a more exact, precise representation (particularly supported by the left IPS) with increasing expertise. These shifts separately indicate the effects of increasing maturity generally in numeric processing and specifically in negative number understanding. PMID:24058350

  2. A real-time microprocessor QRS detector system with a 1-ms timing accuracy for the measurement of ambulatory HRV.

    PubMed

    Ruha, A; Sallinen, S; Nissilä, S

    1997-03-01

    The design, test methods and results of an ambulatory QRS detector are presented. The device is intended for the accurate measurement of heart rate variability (HRV) and reliable QRS detection in both ambulatory and clinical use. The aim of the design work was to achieve high QRS detection performance in terms of timing accuracy and reliability, without compromising the size and power consumption of the device. The complete monitor system consists of a host computer and the detector unit. The detector device is constructed of a commonly available digital signal processing (DSP) microprocessor and other components. The QRS detection algorithm uses optimized prefiltering in conjunction with a matched filter and dual edge threshold detection. The purpose of the prefiltering is to attenuate various noise components in order to achieve improved detection reliability. The matched filter further improves signal-to-noise ratio (SNR) and symmetries the QRS complex for the threshold detection, which is essential in order to achieve the desired performance. The decision for detection is made in real-time and no search-back method is employed. The host computer is used to configure the detector unit, which includes the setting of the matched filter impulse response, and in the retrieval and postprocessing of the measurement results. The QRS detection timing accuracy and detection reliability of the detector system was tested with an artificially generated electrocardiogram (ECG) signal corrupted with various noise types and a timing standard deviation of less than 1 ms was achieved with most noise types and levels similar to those encountered in real measurements. A QRS detection error rate (ER) of 0.1 and 2.2% was achieved with records 103 and 105 from the MIT-BIH Arrhythmia database, respectively. PMID:9216129

  3. Improved Motor-Timing: Effects of Synchronized Metro-Nome Training on Golf Shot Accuracy

    PubMed Central

    Sommer, Marius; Rönnqvist, Louise

    2009-01-01

    This study investigates the effect of synchronized metronome training (SMT) on motor timing and how this training might affect golf shot accuracy. Twenty-six experienced male golfers participated (mean age 27 years; mean golf handicap 12.6) in this study. Pre- and post-test investigations of golf shots made by three different clubs were conducted by use of a golf simulator. The golfers were randomized into two groups: a SMT group and a Control group. After the pre-test, the golfers in the SMT group completed a 4-week SMT program designed to improve their motor timing, the golfers in the Control group were merely training their golf-swings during the same time period. No differences between the two groups were found from the pre-test outcomes, either for motor timing scores or for golf shot accuracy. However, the post-test results after the 4-weeks SMT showed evident motor timing improvements. Additionally, significant improvements for golf shot accuracy were found for the SMT group and with less variability in their performance. No such improvements were found for the golfers in the Control group. As with previous studies that used a SMT program, this study’s results provide further evidence that motor timing can be improved by SMT and that such timing improvement also improves golf accuracy. Key points This study investigates the effect of synchronized metronome training (SMT) on motor timing and how this training might affect golf shot accuracy. A randomized control group design was used. The 4 week SMT intervention showed significant improvements in motor timing, golf shot accuracy, and lead to less variability. We conclude that this study’s results provide further evidence that motor timing can be improved by SMT training and that such timing improvement also improves golf accuracy. PMID:24149608

  4. Deconvolution improves the accuracy and depth sensitivity of time-resolved measurements

    NASA Astrophysics Data System (ADS)

    Diop, Mamadou; St. Lawrence, Keith

    2013-03-01

    Time-resolved (TR) techniques have the potential to distinguish early- from late-arriving photons. Since light travelling through superficial tissue is detected earlier than photons that penetrate the deeper layers, time-windowing can in principle be used to improve the depth sensitivity of TR measurements. However, TR measurements also contain instrument contributions - referred to as the instrument-response-function (IRF) - which cause temporal broadening of the measured temporal-point-spread-function (TPSF). In this report, we investigate the influence of the IRF on pathlength-resolved absorption changes (Δμa) retrieved from TR measurements using the microscopic Beer-Lambert law (MBLL). TPSFs were acquired on homogeneous and two-layer tissue-mimicking phantoms with varying optical properties. The measured IRF and TPSFs were deconvolved to recover the distribution of time-of-flights (DTOFs) of the detected photons. The microscopic Beer-Lambert law was applied to early and late time-windows of the TPSFs and DTOFs to access the effects of the IRF on pathlength-resolved Δμa. The analysis showed that the late part of the TPSFs contains substantial contributions from early-arriving photons, due to the smearing effects of the IRF, which reduced its sensitivity to absorption changes occurring in deep layers. We also demonstrated that the effects of the IRF can be efficiently eliminated by applying a robust deconvolution technique, thereby improving the accuracy and sensitivity of TR measurements to deep-tissue absorption changes.

  5. Accuracy and computational efficiency of real-time subspace propagation schemes for the time-dependent density functional theory

    NASA Astrophysics Data System (ADS)

    Russakoff, Arthur; Li, Yonghui; He, Shenglai; Varga, Kalman

    2016-05-01

    Time-dependent Density Functional Theory (TDDFT) has become successful for its balance of economy and accuracy. However, the application of TDDFT to large systems or long time scales remains computationally prohibitively expensive. In this paper, we investigate the numerical stability and accuracy of two subspace propagation methods to solve the time-dependent Kohn-Sham equations with finite and periodic boundary conditions. The bases considered are the Lánczos basis and the adiabatic eigenbasis. The results are compared to a benchmark fourth-order Taylor expansion of the time propagator. Our results show that it is possible to use larger time steps with the subspace methods, leading to computational speedups by a factor of 2-3 over Taylor propagation. Accuracy is found to be maintained for certain energy regimes and small time scales.

  6. Accuracy and computational efficiency of real-time subspace propagation schemes for the time-dependent density functional theory.

    PubMed

    Russakoff, Arthur; Li, Yonghui; He, Shenglai; Varga, Kalman

    2016-05-28

    Time-dependent Density Functional Theory (TDDFT) has become successful for its balance of economy and accuracy. However, the application of TDDFT to large systems or long time scales remains computationally prohibitively expensive. In this paper, we investigate the numerical stability and accuracy of two subspace propagation methods to solve the time-dependent Kohn-Sham equations with finite and periodic boundary conditions. The bases considered are the Lánczos basis and the adiabatic eigenbasis. The results are compared to a benchmark fourth-order Taylor expansion of the time propagator. Our results show that it is possible to use larger time steps with the subspace methods, leading to computational speedups by a factor of 2-3 over Taylor propagation. Accuracy is found to be maintained for certain energy regimes and small time scales. PMID:27250297

  7. Efficiency and Accuracy of Time-Accurate Turbulent Navier-Stokes Computations

    NASA Technical Reports Server (NTRS)

    Rumsey, Christopher L.; Sanetrik, Mark D.; Biedron, Robert T.; Melson, N. Duane; Parlette, Edward B.

    1995-01-01

    The accuracy and efficiency of two types of subiterations in both explicit and implicit Navier-Stokes codes are explored for unsteady laminar circular-cylinder flow and unsteady turbulent flow over an 18-percent-thick circular-arc (biconvex) airfoil. Grid and time-step studies are used to assess the numerical accuracy of the methods. Nonsubiterative time-stepping schemes and schemes with physical time subiterations are subject to time-step limitations in practice that are removed by pseudo time sub-iterations. Computations for the circular-arc airfoil indicate that a one-equation turbulence model predicts the unsteady separated flow better than an algebraic turbulence model; also, the hysteresis with Mach number of the self-excited unsteadiness due to shock and boundary-layer separation is well predicted.

  8. Individual differences in response speed and accuracy are associated to specific brain activities of two interacting systems

    PubMed Central

    Perri, Rinaldo Livio; Berchicci, Marika; Spinelli, Donatella; Di Russo, Francesco

    2014-01-01

    The study investigates the neurocognitive stages involved in the speed-accuracy trade-off (SAT). Contrary to previous approach, we did not manipulate speed and accuracy instructions: participants were required to be fast and accurate in a go/no-go task, and we selected post-hoc the groups based on the subjects’ spontaneous behavioral tendency. Based on the reaction times, we selected the fast and slow groups (Speed-groups), and based on the percentage of false alarms, we selected the accurate and inaccurate groups (Accuracy-groups). The two Speed-groups were accuracy-matched, and the two Accuracy-groups were speed-matched. High density electroencephalographic (EEG) and stimulus-locked analyses allowed us to observe group differences both before and after the stimulus onset. Long before the stimulus appearance, the two Speed-groups showed different amplitude of the Bereitschaftspotential (BP), reflecting the activity of the supplementary motor area (SMA); by contrast, the two Accuracy-groups showed different amplitude of the prefrontal negativity (pN), reflecting the activity of the right prefrontal cortex (rPFC). In addition, the post-stimulus event-related potential (ERP) components showed differences between groups: the P1 component was larger in accurate than inaccurate group; the N1 and N2 components were larger in the fast than slow group; the P3 component started earlier and was larger in the fast than slow group. The go minus no-go subtractive wave enhancing go-related processing revealed a differential prefrontal positivity (dpP) that peaked at about 330 ms; the latency and the amplitude of this peak were associated with the speed of the decision process and the efficiency of the stimulus-response mapping, respectively. Overall, data are consistent with the view that speed and accuracy are processed by two interacting but separate neurocognitive systems, with different features in both the anticipation and the response execution phases. PMID:25100961

  9. Reaction Time and Accuracy in Individuals with Aphasia during Auditory Vigilance Tasks

    ERIC Educational Resources Information Center

    Laures, Jacqueline S.

    2005-01-01

    Research indicates that attentional deficits exist in aphasic individuals. However, relatively little is known about auditory vigilance performance in individuals with aphasia. The current study explores reaction time (RT) and accuracy in 10 aphasic participants and 10 nonbrain-damaged controls during linguistic and nonlinguistic auditory…

  10. A worldwide unification of GPS (Global Positioning System) antenna coordinates for high accuracy time transfer.

    NASA Astrophysics Data System (ADS)

    Lewandowski, W.

    In the present state of the art of atomic clocks it is desirable that comparisons of these clocks, located in the time metrology laboratories spread around the world, be at the level of a few nanoseconds of accuracy. At present the sole operational way to provide such performance is through the system of GPS satellites. As GPS is a one-way system this implies that special attention must be given to geometrical errors. In order to achieve nanosecond accuracy, the error due to the ground-antenna coordinates should not exceed 1 ns in the global budget of errors of GPS time transfer. To attain this goal the ground-antenna coordinates must be accurately determined in a common worldwide homogeneous geodetic reference frame with uncertainties of order 30 cm. This paper considers the choice of a global reference frame for accurate GPS time transfer and then reports on a worldwide homogenization of GPS antenna coordinates in the principal timing centres.

  11. Classification Consistency and Accuracy for Complex Assessments Using Item Response Theory

    ERIC Educational Resources Information Center

    Lee, Won-Chan

    2010-01-01

    In this article, procedures are described for estimating single-administration classification consistency and accuracy indices for complex assessments using item response theory (IRT). This IRT approach was applied to real test data comprising dichotomous and polytomous items. Several different IRT model combinations were considered. Comparisons…

  12. Two Approaches to Estimation of Classification Accuracy Rate under Item Response Theory

    ERIC Educational Resources Information Center

    Lathrop, Quinn N.; Cheng, Ying

    2013-01-01

    Within the framework of item response theory (IRT), there are two recent lines of work on the estimation of classification accuracy (CA) rate. One approach estimates CA when decisions are made based on total sum scores, the other based on latent trait estimates. The former is referred to as the Lee approach, and the latter, the Rudner approach,…

  13. Network Dynamics Underlying Speed-Accuracy Trade-Offs in Response to Errors

    PubMed Central

    Agam, Yigal; Carey, Caitlin; Barton, Jason J. S.; Dyckman, Kara A.; Lee, Adrian K. C.; Vangel, Mark; Manoach, Dara S.

    2013-01-01

    The ability to dynamically and rapidly adjust task performance based on its outcome is fundamental to adaptive, flexible behavior. Over trials of a task, responses speed up until an error is committed and after the error responses slow down. These dynamic adjustments serve to optimize performance and are well-described by the speed-accuracy trade-off (SATO) function. We hypothesized that SATOs based on outcomes reflect reciprocal changes in the allocation of attention between the internal milieu and the task-at-hand, as indexed by reciprocal changes in activity between the default and dorsal attention brain networks. We tested this hypothesis using functional MRI to examine the pattern of network activation over a series of trials surrounding and including an error. We further hypothesized that these reciprocal changes in network activity are coordinated by the posterior cingulate cortex (PCC) and would rely on the structural integrity of its white matter connections. Using diffusion tensor imaging, we examined whether fractional anisotropy of the posterior cingulum bundle correlated with the magnitude of reciprocal changes in network activation around errors. As expected, reaction time (RT) in trials surrounding errors was consistent with predictions from the SATO function. Activation in the default network was: (i) inversely correlated with RT, (ii) greater on trials before than after an error and (iii) maximal at the error. In contrast, activation in the right intraparietal sulcus of the dorsal attention network was (i) positively correlated with RT and showed the opposite pattern: (ii) less activation before than after an error and (iii) the least activation on the error. Greater integrity of the posterior cingulum bundle was associated with greater reciprocity in network activation around errors. These findings suggest that dynamic changes in attention to the internal versus external milieu in response to errors underlie SATOs in RT and are mediated by the PCC

  14. An Effective Approach to Improving Low-Cost GPS Positioning Accuracy in Real-Time Navigation

    PubMed Central

    Islam, Md. Rashedul; Kim, Jong-Myon

    2014-01-01

    Positioning accuracy is a challenging issue for location-based applications using a low-cost global positioning system (GPS). This paper presents an effective approach to improving the positioning accuracy of a low-cost GPS receiver for real-time navigation. The proposed method precisely estimates position by combining vehicle movement direction, velocity averaging, and distance between waypoints using coordinate data (latitude, longitude, time, and velocity) of the GPS receiver. The previously estimated precious reference point, coordinate translation, and invalid data check also improve accuracy. In order to evaluate the performance of the proposed method, we conducted an experiment using a GARMIN GPS 19xHVS receiver attached to a car and used Google Maps to plot the processed data. The proposed method achieved improvement of 4–10 meters in several experiments. In addition, we compared the proposed approach with two other state-of-the-art methods: recursive averaging and ARMA interpolation. The experimental results show that the proposed approach outperforms other state-of-the-art methods in terms of positioning accuracy. PMID:25136679

  15. Advanced video extensometer for non-contact, real-time, high-accuracy strain measurement.

    PubMed

    Pan, Bing; Tian, Long

    2016-08-22

    We developed an advanced video extensometer for non-contact, real-time, high-accuracy strain measurement in material testing. In the established video extensometer, a "near perfect and ultra-stable" imaging system, combining the idea of active imaging with a high-quality bilateral telecentric lens, is constructed to acquire high-fidelity video images of the test sample surface, which is invariant to ambient lighting changes and small out-of-plane motions occurred between the object surface and image plane. In addition, an efficient and accurate inverse compositional Gauss-Newton algorithm incorporating a temporal initial guess transfer scheme and a high-accuracy interpolation method is employed to achieve real-time, high-accuracy displacement tracking with negligible bias error. Tensile tests of an aluminum sample and a carbon fiber filament sample were performed to demonstrate the efficiency, repeatability and accuracy of the developed advanced video extensometer. The results indicate that longitudinal and transversal strains can be estimated and plotted at a rate of 117 fps and with a maximum strain error less than 30 microstrains. PMID:27557188

  16. An effective approach to improving low-cost GPS positioning accuracy in real-time navigation.

    PubMed

    Islam, Md Rashedul; Kim, Jong-Myon

    2014-01-01

    Positioning accuracy is a challenging issue for location-based applications using a low-cost global positioning system (GPS). This paper presents an effective approach to improving the positioning accuracy of a low-cost GPS receiver for real-time navigation. The proposed method precisely estimates position by combining vehicle movement direction, velocity averaging, and distance between waypoints using coordinate data (latitude, longitude, time, and velocity) of the GPS receiver. The previously estimated precious reference point, coordinate translation, and invalid data check also improve accuracy. In order to evaluate the performance of the proposed method, we conducted an experiment using a GARMIN GPS 19xHVS receiver attached to a car and used Google Maps to plot the processed data. The proposed method achieved improvement of 4-10 meters in several experiments. In addition, we compared the proposed approach with two other state-of-the-art methods: recursive averaging and ARMA interpolation. The experimental results show that the proposed approach outperforms other state-of-the-art methods in terms of positioning accuracy. PMID:25136679

  17. Examination of standardized patient performance: Accuracy and consistency of six standardized patients over time

    PubMed Central

    Erby, Lori A.H.; Roter, Debra L.; Biesecker, Barbara B.

    2011-01-01

    Objective To explore the accuracy and consistency of standardized patient (SP) performance in the context of routine genetic counseling, focusing on elements beyond scripted case items including general communication style and affective demeanor. Methods One hundred seventy-seven genetic counselors were randomly assigned to counsel one of six SPs. Videotapes and transcripts of the sessions were analyzed to assess consistency of performance across four dimensions. Results Accuracy of script item presentation was high; 91% and 89% in the prenatal and cancer cases. However, there were statistically significant differences among SPs in the accuracy of presentation, general communication style, and some aspects of affective presentation. All SPs were rated as presenting with similarly high levels of realism. SP performance over time was generally consistent, with some small but statistically significant differences. Conclusion and practice implications These findings demonstrate that well-trained SPs can not only perform the factual elements of a case with high degrees of accuracy and realism; but they can also maintain sufficient levels of uniformity in general communication style and affective demeanor over time to support their use in even the demanding context of genetic counseling. Results indicate a need for an additional focus in training on consistency between different SPs. PMID:21094590

  18. Climatic Associations of British Species Distributions Show Good Transferability in Time but Low Predictive Accuracy for Range Change

    PubMed Central

    Rapacciuolo, Giovanni; Roy, David B.; Gillings, Simon; Fox, Richard; Walker, Kevin; Purvis, Andy

    2012-01-01

    Conservation planners often wish to predict how species distributions will change in response to environmental changes. Species distribution models (SDMs) are the primary tool for making such predictions. Many methods are widely used; however, they all make simplifying assumptions, and predictions can therefore be subject to high uncertainty. With global change well underway, field records of observed range shifts are increasingly being used for testing SDM transferability. We used an unprecedented distribution dataset documenting recent range changes of British vascular plants, birds, and butterflies to test whether correlative SDMs based on climate change provide useful approximations of potential distribution shifts. We modelled past species distributions from climate using nine single techniques and a consensus approach, and projected the geographical extent of these models to a more recent time period based on climate change; we then compared model predictions with recent observed distributions in order to estimate the temporal transferability and prediction accuracy of our models. We also evaluated the relative effect of methodological and taxonomic variation on the performance of SDMs. Models showed good transferability in time when assessed using widespread metrics of accuracy. However, models had low accuracy to predict where occupancy status changed between time periods, especially for declining species. Model performance varied greatly among species within major taxa, but there was also considerable variation among modelling frameworks. Past climatic associations of British species distributions retain a high explanatory power when transferred to recent time – due to their accuracy to predict large areas retained by species – but fail to capture relevant predictors of change. We strongly emphasize the need for caution when using SDMs to predict shifts in species distributions: high explanatory power on temporally-independent records – as assessed

  19. Interpersonal variability in timing strategy and temporal accuracy in rapid interception task with variable time-to-contact.

    PubMed

    Ijiri, Tetsuya; Shinya, Masahiro; Nakazawa, Kimitaka

    2015-01-01

    In rapid interceptive actions such as hitting a baseball, cricket ball or tennis ball, ball speed varies between trials, and players have to compensate the time lag by controlling the moment of movement onset and movement duration. Previous studies have found that these two variables can flexibly co-vary and are robustly influenced by target speed (i.e. velocity-coupling effect: faster movement for faster target). However, some studies reported an interpersonal variability in the timing control strategy and the relationship between the strategy and temporal accuracy in rapid interception is unclear. We used a baseball-simulated rapid interceptive task to assess this issue. Under relatively easy time constraints, there was a large interpersonal variability, and participants were distinctively divided into two groups: those who mainly modulated their movement duration and those who mainly controlled their movement onset. When the time constraint became severe, the second strategy shifted to the first strategy in most of the second group participants. In the both cases, being able to mainly control movement onset resulted in higher temporal accuracy. These results suggest that minimising the velocity-coupling effect is an important factor to achieve high temporal accuracy in rapid interception. PMID:25277080

  20. Accuracy of Pedometer Steps and Time for Youth with Intellectual Disabilities during Dynamic Movements

    ERIC Educational Resources Information Center

    Pitetti, Kenneth H.; Beets, Michael W.; Flaming, Judy

    2009-01-01

    Pedometer accuracy for steps and activity time during dynamic movement for youth with intellectual disabilities (ID) were examined. Twenty-four youth with ID (13 girls, 13.1 [plus or minus] 3.2 yrs; 11 boys, 14.7 [plus or minus] 2.7 yrs) were videotaped during adapted physical education class while wearing a Walk4Life 2505 pedometer in five…

  1. 28 CFR 542.18 - Response time.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Response time. 542.18 Section 542.18... REMEDY Administrative Remedy Program § 542.18 Response time. If accepted, a Request or Appeal is... later than the third calendar day after filing. If the time period for response to a Request or...

  2. Accuracy and responses of genomic selection on key traits in apple breeding

    PubMed Central

    Muranty, Hélène; Troggio, Michela; Sadok, Inès Ben; Rifaï, Mehdi Al; Auwerkerken, Annemarie; Banchi, Elisa; Velasco, Riccardo; Stevanato, Piergiorgio; van de Weg, W Eric; Di Guardo, Mario; Kumar, Satish; Laurens, François; Bink, Marco C A M

    2015-01-01

    The application of genomic selection in fruit tree crops is expected to enhance breeding efficiency by increasing prediction accuracy, increasing selection intensity and decreasing generation interval. The objectives of this study were to assess the accuracy of prediction and selection response in commercial apple breeding programmes for key traits. The training population comprised 977 individuals derived from 20 pedigreed full-sib families. Historic phenotypic data were available on 10 traits related to productivity and fruit external appearance and genotypic data for 7829 SNPs obtained with an Illumina 20K SNP array. From these data, a genome-wide prediction model was built and subsequently used to calculate genomic breeding values of five application full-sib families. The application families had genotypes at 364 SNPs from a dedicated 512 SNP array, and these genotypic data were extended to the high-density level by imputation. These five families were phenotyped for 1 year and their phenotypes were compared to the predicted breeding values. Accuracy of genomic prediction across the 10 traits reached a maximum value of 0.5 and had a median value of 0.19. The accuracies were strongly affected by the phenotypic distribution and heritability of traits. In the largest family, significant selection response was observed for traits with high heritability and symmetric phenotypic distribution. Traits that showed non-significant response often had reduced and skewed phenotypic variation or low heritability. Among the five application families the accuracies were uncorrelated to the degree of relatedness to the training population. The results underline the potential of genomic prediction to accelerate breeding progress in outbred fruit tree crops that still need to overcome long generation intervals and extensive phenotyping costs. PMID:26744627

  3. Travel-time source-specific station correction improves location accuracy

    NASA Astrophysics Data System (ADS)

    Giuntini, Alessandra; Materni, Valerio; Chiappini, Stefano; Carluccio, Roberto; Console, Rodolfo; Chiappini, Massimo

    2013-04-01

    Accurate earthquake locations are crucial for investigating seismogenic processes, as well as for applications like verifying compliance to the Comprehensive Test Ban Treaty (CTBT). Earthquake location accuracy is related to the degree of knowledge about the 3-D structure of seismic wave velocity in the Earth. It is well known that modeling errors of calculated travel times may have the effect of shifting the computed epicenters far from the real locations by a distance even larger than the size of the statistical error ellipses, regardless of the accuracy in picking seismic phase arrivals. The consequences of large mislocations of seismic events in the context of the CTBT verification is particularly critical in order to trigger a possible On Site Inspection (OSI). In fact, the Treaty establishes that an OSI area cannot be larger than 1000 km2, and its larger linear dimension cannot be larger than 50 km. Moreover, depth accuracy is crucial for the application of the depth event screening criterion. In the present study, we develop a method of source-specific travel times corrections based on a set of well located events recorded by dense national seismic networks in seismically active regions. The applications concern seismic sequences recorded in Japan, Iran and Italy. We show that mislocations of the order of 10-20 km affecting the epicenters, as well as larger mislocations in hypocentral depths, calculated from a global seismic network and using the standard IASPEI91 travel times can be effectively removed by applying source-specific station corrections.

  4. Accuracy of System Step Response Roll Magnitude Estimation from Central and Peripheral Visual Displays and Simulator Cockpit Motion

    NASA Technical Reports Server (NTRS)

    Hosman, R. J. A. W.; Vandervaart, J. C.

    1984-01-01

    An experiment to investigate visual roll attitude and roll rate perception is described. The experiment was also designed to assess the improvements of perception due to cockpit motion. After the onset of the motion, subjects were to make accurate and quick estimates of the final magnitude of the roll angle step response by pressing the appropriate button of a keyboard device. The differing time-histories of roll angle, roll rate and roll acceleration caused by a step response stimulate the different perception processes related the central visual field, peripheral visual field and vestibular organs in different, yet exactly known ways. Experiments with either of the visual displays or cockpit motion and some combinations of these were run to asses the roles of the different perception processes. Results show that the differences in response time are much more pronounced than the differences in perception accuracy.

  5. Towards investigation of evolution of dynamical systems with independence of time accuracy: more classes of systems

    NASA Astrophysics Data System (ADS)

    Gurzadyan, V. G.; Kocharyan, A. A.

    2015-07-01

    The recently developed method (Paper 1) enabling one to investigate the evolution of dynamical systems with an accuracy not dependent on time is developed further. The classes of dynamical systems which can be studied by that method are much extended, now including systems that are: (1) non-Hamiltonian, conservative; (2) Hamiltonian with time-dependent perturbation; (3) non-conservative (with dissipation). These systems cover various types of N-body gravitating systems of astrophysical and cosmological interest, such as the orbital evolution of planets, minor planets, artificial satellites due to tidal, non-tidal perturbations and thermal thrust, evolving close binary stellar systems, and the dynamics of accretion disks.

  6. Gated audiovisual speech identification in silence vs. noise: effects on time and accuracy

    PubMed Central

    Moradi, Shahram; Lidestam, Björn; Rönnberg, Jerker

    2013-01-01

    This study investigated the degree to which audiovisual presentation (compared to auditory-only presentation) affected isolation point (IPs, the amount of time required for the correct identification of speech stimuli using a gating paradigm) in silence and noise conditions. The study expanded on the findings of Moradi et al. (under revision), using the same stimuli, but presented in an audiovisual instead of an auditory-only manner. The results showed that noise impeded the identification of consonants and words (i.e., delayed IPs and lowered accuracy), but not the identification of final words in sentences. In comparison with the previous study by Moradi et al., it can be concluded that the provision of visual cues expedited IPs and increased the accuracy of speech stimuli identification in both silence and noise. The implication of the results is discussed in terms of models for speech understanding. PMID:23801980

  7. Evaluating Cognitive Theory: A Joint Modeling Approach Using Responses and Response Times

    ERIC Educational Resources Information Center

    Klein Entink, Rinke H.; Kuhn, Jorg-Tobias; Hornke, Lutz F.; Fox, Jean-Paul

    2009-01-01

    In current psychological research, the analysis of data from computer-based assessments or experiments is often confined to accuracy scores. Response times, although being an important source of additional information, are either neglected or analyzed separately. In this article, a new model is developed that allows the simultaneous analysis of…

  8. Mayer waves reduce the accuracy of estimated hemodynamic response functions in functional near-infrared spectroscopy.

    PubMed

    Yücel, Meryem A; Selb, Juliette; Aasted, Christopher M; Lin, Pei-Yi; Borsook, David; Becerra, Lino; Boas, David A

    2016-08-01

    Analysis of cerebral hemodynamics reveals a wide spectrum of oscillations ranging from 0.0095 to 2 Hz. While most of these oscillations can be filtered out during analysis of functional near-infrared spectroscopy (fNIRS) signals when estimating stimulus evoked hemodynamic responses, oscillations around 0.1 Hz are an exception. This is due to the fact that they share a common spectral range with typical stimulus evoked hemodynamic responses from the brain. Here we investigate the effect of hemodynamic oscillations around 0.1 Hz on the estimation of hemodynamic response functions from fNIRS data. Our results show that for an expected response of ~1 µM in oxygenated hemoglobin concentration (HbO), Mayer wave oscillations with an amplitude > ~1 µM at 0.1 Hz reduce the accuracy of the estimated response as quantified by a 3 fold increase in the mean squared error and decrease in correlation (R(2) below 0.78) when compared to the true HRF. These results indicate that the amplitude of oscillations at 0.1 Hz can serve as an objective metric of the expected HRF estimation accuracy. In addition, we investigated the effect of short separation regression on the recovered HRF, and found that this improves the recovered HRF when large amplitude 0.1 Hz oscillations are present in fNIRS data. We suspect that the development of other filtering strategies may provide even further improvement. PMID:27570699

  9. Mayer waves reduce the accuracy of estimated hemodynamic response functions in functional near-infrared spectroscopy

    PubMed Central

    Yücel, Meryem A.; Selb, Juliette; Aasted, Christopher M.; Lin, Pei-Yi; Borsook, David; Becerra, Lino; Boas, David A.

    2016-01-01

    Analysis of cerebral hemodynamics reveals a wide spectrum of oscillations ranging from 0.0095 to 2 Hz. While most of these oscillations can be filtered out during analysis of functional near-infrared spectroscopy (fNIRS) signals when estimating stimulus evoked hemodynamic responses, oscillations around 0.1 Hz are an exception. This is due to the fact that they share a common spectral range with typical stimulus evoked hemodynamic responses from the brain. Here we investigate the effect of hemodynamic oscillations around 0.1 Hz on the estimation of hemodynamic response functions from fNIRS data. Our results show that for an expected response of ~1 µM in oxygenated hemoglobin concentration (HbO), Mayer wave oscillations with an amplitude > ~1 µM at 0.1 Hz reduce the accuracy of the estimated response as quantified by a 3 fold increase in the mean squared error and decrease in correlation (R2 below 0.78) when compared to the true HRF. These results indicate that the amplitude of oscillations at 0.1 Hz can serve as an objective metric of the expected HRF estimation accuracy. In addition, we investigated the effect of short separation regression on the recovered HRF, and found that this improves the recovered HRF when large amplitude 0.1 Hz oscillations are present in fNIRS data. We suspect that the development of other filtering strategies may provide even further improvement. PMID:27570699

  10. A simple method for improving the time-stepping accuracy in atmosphere and ocean models

    NASA Astrophysics Data System (ADS)

    Williams, P. D.

    2012-12-01

    In contemporary numerical simulations of the atmosphere and ocean, evidence suggests that time-stepping errors may be a significant component of total model error, on both weather and climate time-scales. This presentation will review the available evidence, and will then suggest a simple but effective method for substantially improving the time-stepping numerics at no extra computational expense. A common time-stepping method in atmosphere and ocean models is the leapfrog scheme combined with the Robert-Asselin (RA) filter. This method is used in the following models (and many more): ECHAM, MAECHAM, MM5, CAM, MESO-NH, HIRLAM, KMCM, LIMA, SPEEDY, IGCM, PUMA, COSMO, FSU-GSM, FSU-NRSM, NCEP-GFS, NCEP-RSM, NSEAM, NOGAPS, RAMS, and CCSR/NIES-AGCM. Although the RA filter controls the time-splitting instability, it also introduces non-physical damping and reduces the accuracy. This presentation proposes a simple modification to the RA filter, which has become known as the RAW filter (Williams 2009, 2011). When used in conjunction with the leapfrog scheme, the RAW filter eliminates the non-physical damping and increases the amplitude accuracy by two orders, yielding third-order accuracy. (The phase accuracy remains second-order.) The RAW filter can easily be incorporated into existing models, typically via the insertion of just a single line of code. Better simulations are obtained at no extra computational expense. Results will be shown from recent implementations of the RAW filter in various models, including SPEEDY and COSMO. For example, in SPEEDY, the skill of weather forecasts is found to be significantly improved. In particular, in tropical surface pressure predictions, five-day forecasts made using the RAW filter have approximately the same skill as four-day forecasts made using the RA filter (Amezcua, Kalnay & Williams 2011). These improvements are encouraging for the use of the RAW filter in other atmosphere and ocean models. References PD Williams (2009) A

  11. The time course effect of moderate intensity exercise on response execution and response inhibition.

    PubMed

    Joyce, Jennifer; Graydon, Jan; McMorris, Terry; Davranche, Karen

    2009-10-01

    This research aimed to investigate the time course effect of a moderate steady-state exercise session on response execution and response inhibition using a stop-task paradigm. Ten participants performed a stop-signal task whilst cycling at a carefully controlled workload intensity (40% of maximal aerobic power), immediately following exercise and 30min after exercise cessation. Results showed that moderate exercise enhances a subjects' ability to execute responses under time pressure (shorter Go reaction time, RT without a change in accuracy) but also enhances a subjects' ability to withhold ongoing motor responses (shorter stop-signal RT). The present outcomes reveal that the beneficial effect of exercise is neither limited to motor response tasks, nor to cognitive tasks performed during exercise. Beneficial effects of exercise remain present on both response execution and response inhibition performance for up to 52min after exercise cessation. PMID:19346049

  12. Pistol shooting accuracy as dependent on experience, eyes being opened and available viewing time.

    PubMed

    Goonetilleke, Ravindra S; Hoffmann, Errol R; Lau, Wing Chung

    2009-05-01

    A study of the shooting accuracy of three groups of pistol shooters is reported. The groups included (i) experienced gas pistol shooters; (ii) persons with experience in video shooting games; and (iii) persons with no shooting experience. The viewing time was varied in the tests. The results showed that experience had a significant effect on the mean and root mean square (RMS) shooting errors at the target. The results also showed that the viewing time does not need to exceed about 2s for an experienced pistol shooter and about 3s for a novice shooter to reach the best performance. Two models for the effects of limited viewing time are proposed; both models fit the data well when the viewing time is less than about 2s. The results indicated that the differences occurring with varying levels of experience are due to postural balance and not due to the aiming or cognitive component of the task. PMID:18992872

  13. Dynamics of Word Comprehension in Infancy: Developments in Timing, Accuracy, and Resistance to Acoustic Degradation

    PubMed Central

    Zangl, Renate; Klarman, Lindsay; Thal, Donna; Fernald, Anne; Bates, Elizabeth

    2011-01-01

    Online comprehension of naturally spoken and perceptually degraded words was assessed in 95 children ages 12 to 31 months. The time course of word recognition was measured by monitoring eye movements as children looked at pictures while listening to familiar target words presented in unaltered, time-compressed, and low-pass-filtered forms. Success in word recognition varied with age and level of vocabulary development, and with the perceptual integrity of the word. Recognition was best overall for unaltered words, lower for time-compressed words, and significantly lower in low-pass-filtered words. Reaction times were fastest in compressed, followed by unaltered and filtered words. Results showed that children were able to recognize familiar words in challenging conditions and that productive vocabulary size was more sensitive than chronological age as a predictor of children’s accuracy and speed in word recognition. PMID:22072948

  14. Accuracy issues in the finite difference time domain simulation of photomask scattering

    NASA Astrophysics Data System (ADS)

    Pistor, Thomas V.

    2001-09-01

    As the use of electromagnetic simulation in lithography increases, accuracy issues are uncovered and must be addressed. A proper understanding of these issues can allow the lithographer to avoid pitfalls in electromagnetic simulation and to know what can and can not be accurately simulated. This paper addresses the important accuracy issues related to the simulation of photomask scattering using the Finite Difference Time Domain (FDTD) method. Errors related to discretization and periodic boundary conditions are discussed. Discretization-related issues arise when derivatives are replaced by finite differences and when integrals are replaced by summations. These approximations can lead to mask features that do not have exact dimensions. The effects of discretization error on phase wells and thin films are shown. The reflectivity of certain thin film layers is seen to be very sensitive to the layer thickness. Simulation experiments and theory are used to determine how fine a discretization is necessary and various discretization schemes that help minimize error are presented. Boundary-condition-related errors arise from the use of periodic boundary conditions when simulating isolated mask features. The effects of periodic boundary conditions are assessed through the use of simulation experiments. All errors are associated with an ever-present trade-off between accuracy and computational resources. However, choosing the cell size wisely can, in many cases, minimize error without significantly increasing computation resource requirements.

  15. Accuracy of the Timed Up and Go test for predicting sarcopenia in elderly hospitalized patients

    PubMed Central

    Martinez, Bruno Prata; Gomes, Isabela Barboza; de Oliveira, Carolina Santana; Ramos, Isis Resende; Rocha, Mônica Diniz Marques; Júnior, Luiz Alberto Forgiarini; Camelier, Fernanda Warken Rosa; Camelier, Aquiles Assunção

    2015-01-01

    OBJECTIVES: The ability of the Timed Up and Go test to predict sarcopenia has not been evaluated previously. The objective of this study was to evaluate the accuracy of the Timed Up and Go test for predicting sarcopenia in elderly hospitalized patients. METHODS: This cross-sectional study analyzed 68 elderly patients (≥60 years of age) in a private hospital in the city of Salvador-BA, Brazil, between the 1st and 5th day of hospitalization. The predictive variable was the Timed Up and Go test score, and the outcome of interest was the presence of sarcopenia (reduced muscle mass associated with a reduction in handgrip strength and/or weak physical performance in a 6-m gait-speed test). After the descriptive data analyses, the sensitivity, specificity and accuracy of a test using the predictive variable to predict the presence of sarcopenia were calculated. RESULTS: In total, 68 elderly individuals, with a mean age 70.4±7.7 years, were evaluated. The subjects had a Charlson Comorbidity Index score of 5.35±1.97. Most (64.7%) of the subjects had a clinical admission profile; the main reasons for hospitalization were cardiovascular disorders (22.1%), pneumonia (19.1%) and abdominal disorders (10.2%). The frequency of sarcopenia in the sample was 22.1%, and the mean length of time spent performing the Timed Up and Go test was 10.02±5.38 s. A time longer than or equal to a cutoff of 10.85 s on the Timed Up and Go test predicted sarcopenia with a sensitivity of 67% and a specificity of 88.7%. The accuracy of this cutoff for the Timed Up and Go test was good (0.80; IC=0.66-0.94; p=0.002). CONCLUSION: The Timed Up and Go test was shown to be a predictor of sarcopenia in elderly hospitalized patients. PMID:26039955

  16. Classification Accuracy of Mixed Format Tests: A Bi-Factor Item Response Theory Approach

    PubMed Central

    Wang, Wei; Drasgow, Fritz; Liu, Liwen

    2016-01-01

    Mixed format tests (e.g., a test consisting of multiple-choice [MC] items and constructed response [CR] items) have become increasingly popular. However, the latent structure of item pools consisting of the two formats is still equivocal. Moreover, the implications of this latent structure are unclear: For example, do constructed response items tap reasoning skills that cannot be assessed with multiple choice items? This study explored the dimensionality of mixed format tests by applying bi-factor models to 10 tests of various subjects from the College Board's Advanced Placement (AP) Program and compared the accuracy of scores based on the bi-factor analysis with scores derived from a unidimensional analysis. More importantly, this study focused on a practical and important question—classification accuracy of the overall grade on a mixed format test. Our findings revealed that the degree of multidimensionality resulting from the mixed item format varied from subject to subject, depending on the disattenuated correlation between scores from MC and CR subtests. Moreover, remarkably small decrements in classification accuracy were found for the unidimensional analysis when the disattenuated correlations exceeded 0.90. PMID:26973568

  17. Eye Exercises Enhance Accuracy and Letter Recognition, but Not Reaction Time, in a Modified Rapid Serial Visual Presentation Task

    PubMed Central

    Di Noto, Paula; Uta, Sorin; DeSouza, Joseph F. X.

    2013-01-01

    Eye exercises have been prescribed to resolve a multitude of eye-related problems. However, studies on the efficacy of eye exercises are lacking, mainly due to the absence of simple assessment tools in the clinic. Because similar regions of the brain are responsible for eye movements and visual attention, we used a modified rapid serial visual presentation (RSVP) to assess any measurable effect of short-term eye exercise in improvements within these domains. In the present study, twenty subjects were equally divided into control and experimental groups, each of which performed a pre-training RSVP assessment where target letters, to which subjects were asked to respond to by pressing a spacebar, were serially and rapidly presented. Response time to target letters, accuracy of correctly responding to target letters, and correct identification of target letters in each of 12 sessions was measured. The experimental group then performed active eye exercises, while the control group performed a task that minimized eye movements for 18.5 minutes. A final post-training RSVP assessment was performed by both groups and response time, accuracy, and letter identification were compared between and within subject groups both pre- and post-training. Subjects who performed eye exercises were more accurate in responding to target letters separated by one distractor and in letter identification in the post-training RSVP assessment, while latency of responses were unchanged between and within groups. This suggests that eye exercises may prove useful in enhancing cognitive performance on tasks related to attention and memory over a very brief course of training, and RSVP may be a useful measure of this efficacy. Further research is needed on eye exercises to determine whether they are an effective treatment for patients with cognitive and eye-related disorders. PMID:23527146

  18. Comprehensive Numerical Analysis of Finite Difference Time Domain Methods for Improving Optical Waveguide Sensor Accuracy

    PubMed Central

    Samak, M. Mosleh E. Abu; Bakar, A. Ashrif A.; Kashif, Muhammad; Zan, Mohd Saiful Dzulkifly

    2016-01-01

    This paper discusses numerical analysis methods for different geometrical features that have limited interval values for typically used sensor wavelengths. Compared with existing Finite Difference Time Domain (FDTD) methods, the alternating direction implicit (ADI)-FDTD method reduces the number of sub-steps by a factor of two to three, which represents a 33% time savings in each single run. The local one-dimensional (LOD)-FDTD method has similar numerical equation properties, which should be calculated as in the previous method. Generally, a small number of arithmetic processes, which result in a shorter simulation time, are desired. The alternating direction implicit technique can be considered a significant step forward for improving the efficiency of unconditionally stable FDTD schemes. This comparative study shows that the local one-dimensional method had minimum relative error ranges of less than 40% for analytical frequencies above 42.85 GHz, and the same accuracy was generated by both methods.

  19. Influence of spatial accuracy constraints on reaction time and maximum speed of performance of unilateral movements.

    PubMed

    Gutnik, B; Skurvydas, A; Zuoza, A; Zuoziene, I; Mickevičienė, D; Alekrinskis, B A; Pukenas, K; Nash, D

    2015-04-01

    The goal was to study reaction time and maximal velocity of upper limbs of healthy young adults of both sexes during transition from a simple to a more involved task. Performance of dominant and non-dominant arms was recorded. Participants were 43 healthy, right-handed, untrained men (n=22) and women (n=21), 18-22 years old. The simple task required a single jerk-like movement. The involved task required both speed and accuracy where necessity for high speed of performance was emphasized. The effectiveness of transition between tasks was calculated for both reaction time and maximal velocity. No lateral differences were found. Men usually had a shorter reaction time on both tasks and a higher maximal velocity in the simple task. Women were more effective at modifying velocity. PMID:25799027

  20. Effects of training and simulated combat stress on leg tourniquet application accuracy, time, and effectiveness.

    PubMed

    Schreckengaust, Richard; Littlejohn, Lanny; Zarow, Gregory J

    2014-02-01

    The lower extremity tourniquet failure rate remains significantly higher in combat than in preclinical testing, so we hypothesized that tourniquet placement accuracy, speed, and effectiveness would improve during training and decline during simulated combat. Navy Hospital Corpsman (N = 89), enrolled in a Tactical Combat Casualty Care training course in preparation for deployment, applied Combat Application Tourniquet (CAT) and the Special Operations Forces Tactical Tourniquet (SOFT-T) on day 1 and day 4 of classroom training, then under simulated combat, wherein participants ran an obstacle course to apply a tourniquet while wearing full body armor and avoiding simulated small arms fire (paint balls). Application time and pulse elimination effectiveness improved day 1 to day 4 (p < 0.005). Under simulated combat, application time slowed significantly (p < 0.001), whereas accuracy and effectiveness declined slightly. Pulse elimination was poor for CAT (25% failure) and SOFT-T (60% failure) even in classroom conditions following training. CAT was more quickly applied (p < 0.005) and more effective (p < 0.002) than SOFT-T. Training fostered fast and effective application of leg tourniquets while performance declined under simulated combat. The inherent efficacy of tourniquet products contributes to high failure rates under combat conditions, pointing to the need for superior tourniquets and for rigorous deployment preparation training in simulated combat scenarios. PMID:24491604

  1. Effects of machining accuracy on frequency response properties of thick-screen frequency selective surface

    NASA Astrophysics Data System (ADS)

    Fang, Chunyi; Gao, Jinsong; Xin, Chen

    2012-10-01

    Electromagnetic theory shows that a thick-screen frequency selective surface (FSS) has many advantages in its frequency response characteristics. In addition, it can be used to make a stealth radome. Therefore, we research in detail how machining accuracy affects the frequency response properties of the FSS in the gigahertz range. Specifically, by using the least squares method applied to machining data, the effects of different machining precision in the samples can be calculated thus obtaining frequency response curves which were verified by testing in the near-field in a microwave dark room. The results show that decreasing roughness and flatness variation leads to an increase in the bandwidth and that an increase in spacing error leads to the center frequency drifting lower. Finally, an increase in aperture error leads to an increase in bandwidth. Therefore, the conclusion is that machining accuracy should be controlled and that a spatial error less than 0.05 mm is required in order to avoid unwanted center frequency drift and a transmittance decrease.

  2. Premotor and Motor Reaction Time as a Function of Response Complexity.

    ERIC Educational Resources Information Center

    Christina, Robert W.; Rose, Debra J.

    1985-01-01

    Two experiments were conducted to identify response elements responsible for the complexity effect found by Henry and Rogers. Results suggest that, as the number of movement parts and the accuracy demands increase, programing time increases, supporting the hypothesis that response initiation time becomes longer as programing becomes more complex.…

  3. Accuracy and reproducibility of bending stiffness measurements by mechanical response tissue analysis in artificial human ulnas.

    PubMed

    Arnold, Patricia A; Ellerbrock, Emily R; Bowman, Lyn; Loucks, Anne B

    2014-11-01

    Osteoporosis is characterized by reduced bone strength, but no FDA-approved medical device measures bone strength. Bone strength is strongly associated with bone stiffness, but no FDA-approved medical device measures bone stiffness either. Mechanical Response Tissue Analysis (MRTA) is a non-significant risk, non-invasive, radiation-free, vibration analysis technique for making immediate, direct functional measurements of the bending stiffness of long bones in humans in vivo. MRTA has been used for research purposes for more than 20 years, but little has been published about its accuracy. To begin to investigate its accuracy, we compared MRTA measurements of bending stiffness in 39 artificial human ulna bones to measurements made by Quasistatic Mechanical Testing (QMT). In the process, we also quantified the reproducibility (i.e., precision and repeatability) of both methods. MRTA precision (1.0±1.0%) and repeatability (3.1 ± 3.1%) were not as high as those of QMT (0.2 ± 0.2% and 1.3+1.7%, respectively; both p<10(-4)). The relationship between MRTA and QMT measurements of ulna bending stiffness was indistinguishable from the identity line (p=0.44) and paired measurements by the two methods agreed within a 95% confidence interval of ± 5%. If such accuracy can be achieved on real human ulnas in situ, and if the ulna is representative of the appendicular skeleton, MRTA may prove clinically useful. PMID:25261885

  4. 28 CFR 542.18 - Response time.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Response time. 542.18 Section 542.18 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INSTITUTIONAL MANAGEMENT ADMINISTRATIVE REMEDY Administrative Remedy Program § 542.18 Response time. If accepted, a Request or Appeal...

  5. 28 CFR 542.18 - Response time.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Response time. 542.18 Section 542.18 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INSTITUTIONAL MANAGEMENT ADMINISTRATIVE REMEDY Administrative Remedy Program § 542.18 Response time. If accepted, a Request or Appeal...

  6. 28 CFR 542.18 - Response time.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 2 2013-07-01 2013-07-01 false Response time. 542.18 Section 542.18 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INSTITUTIONAL MANAGEMENT ADMINISTRATIVE REMEDY Administrative Remedy Program § 542.18 Response time. If accepted, a Request or Appeal...

  7. 28 CFR 542.18 - Response time.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Response time. 542.18 Section 542.18 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INSTITUTIONAL MANAGEMENT ADMINISTRATIVE REMEDY Administrative Remedy Program § 542.18 Response time. If accepted, a Request or Appeal...

  8. 29 CFR 1610.9 - Responses: timing.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 4 2012-07-01 2012-07-01 false Responses: timing. 1610.9 Section 1610.9 Labor Regulations Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION AVAILABILITY OF RECORDS Production or Disclosure Under 5 U.S.C. 552 § 1610.9 Responses: timing. (a) The Legal Counsel's designee, the regional attorney, or the regional...

  9. 29 CFR 1610.9 - Responses: timing.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 4 2014-07-01 2014-07-01 false Responses: timing. 1610.9 Section 1610.9 Labor Regulations Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION AVAILABILITY OF RECORDS Production or Disclosure Under 5 U.S.C. 552 § 1610.9 Responses: timing. (a) The EEOC utilizes a multitrack system for responding to FOIA requests....

  10. 29 CFR 1610.9 - Responses: timing.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 4 2013-07-01 2013-07-01 false Responses: timing. 1610.9 Section 1610.9 Labor Regulations Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION AVAILABILITY OF RECORDS Production or Disclosure Under 5 U.S.C. 552 § 1610.9 Responses: timing. (a) The EEOC utilizes a multitrack system for responding to FOIA requests....

  11. 29 CFR 1610.9 - Responses: timing.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 4 2011-07-01 2011-07-01 false Responses: timing. 1610.9 Section 1610.9 Labor Regulations Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION AVAILABILITY OF RECORDS Production or Disclosure Under 5 U.S.C. 552 § 1610.9 Responses: timing. (a) The Legal Counsel's designee, the regional attorney, or the regional...

  12. Accuracy validation of T2L2 time transfer in co-location.

    PubMed

    Laas-Bourez, Myrtille; Courde, Clément; Samain, Etienne; Exertier, Pierre; Guillemot, Philippe; Torre, Jean-Marie; Martin, Nicolas; Foussard, Claude

    2015-02-01

    The Time Transfer by Laser Link (T2L2) experiment has been developed in close collaboration between Centre National d'Etudes Spatiales and Observatoire de la Côte d'Azur. The aim is to synchronize remote ultra-stable clocks over large-scale distances using two laser ranging stations. This ground to space time transfer has been derived from laser telemetry technology with dedicated space equipment designed to record arrival time of laser pulses on board the satellite. For 3 years, specific campaigns have been organized to prove T2L2 performance. In April 2012, we performed a 2-week campaign with our two laser ranging stations, Métrologie Optique and French Transportable Laser Ranging Station, to demonstrate the T2L2 time transfer accuracy in co-location. We have compared three independent time transfer techniques: T2L2, GPS, and direct measurement, with both an event timer and an interval counter. The most important result obtained in this campaign was a mean agreement between T2L2 and a direct comparison better than 200 ps. This is the first major step to validate the uncertainty budget of the entire T2L2 experiment. This paper focuses on this campaign setup and the obtained results. PMID:25643076

  13. Accuracy enhancement of GPS time series using principal component analysis and block spatial filtering

    NASA Astrophysics Data System (ADS)

    He, Xiaoxing; Hua, Xianghong; Yu, Kegen; Xuan, Wei; Lu, Tieding; Zhang, W.; Chen, X.

    2015-03-01

    This paper focuses on performance analysis and accuracy enhancement of long-term position time series of a regional network of GPS stations with two near sub-blocks, one block of 8 stations in Cascadia region and another block of 14 stations in Southern California. We have analyzed the seasonal variations of the 22 IGS site positions between 2004 and 2011. The Green's function is used to calculate the station-site displacements induced by the environmental loading due to atmospheric pressure, soil moisture, snow depth and nontidal ocean. The analysis has revealed that these loading factors can result in position shift of centimeter level, the displacement time series exhibit a periodic pattern, which can explain about 12.70-21.78% of the seasonal amplitude on vertical GPS time series, and the loading effect is significantly different among the two nearby geographical regions. After the loading effect is corrected, the principal component analysis (PCA)-based block spatial filtering is proposed to filter out the remaining common mode error (CME) of the GPS time series. The results show that the PCA-based block spatial filtering can extract the CME more accurately and effectively than the conventional overall filtering method, reducing more of the uncertainty. With the loading correction and block spatial filtering, about 68.34-73.20% of the vertical GPS seasonal power can be separated and removed, improving the reliability of the GPS time series and hence enabling better deformation analysis and higher precision geodetic applications.

  14. Sex differences in accuracy and precision when judging time to arrival: data from two Internet studies.

    PubMed

    Sanders, Geoff; Sinclair, Kamila

    2011-12-01

    We report two Internet studies that investigated sex differences in the accuracy and precision of judging time to arrival. We used accuracy to mean the ability to match the actual time to arrival and precision to mean the consistency with which each participant made their judgments. Our task was presented as a computer game in which a toy UFO moved obliquely towards the participant through a virtual three-dimensional space on route to a docking station. The UFO disappeared before docking and participants pressed their space bar at the precise moment they thought the UFO would have docked. Study 1 showed it was possible to conduct quantitative studies of spatiotemporal judgments in virtual reality via the Internet and confirmed reports that men are more accurate because women underestimate, but found no difference in precision measured as intra-participant variation. Study 2 repeated Study 1 with five additional presentations of one condition to provide a better measure of precision. Again, men were more accurate than women but there were no sex differences in precision. However, within the coincidence-anticipation timing (CAT) literature, of those studies that report sex differences, a majority found that males are both more accurate and more precise than females. Noting that many CAT studies report no sex differences, we discuss appropriate interpretations of such null findings. While acknowledging that CAT performance may be influenced by experience we suggest that the sex difference may have originated among our ancestors with the evolutionary selection of men for hunting and women for gathering. PMID:21125324

  15. Intracranial aneurysms: Diagnostics accuracy of three-dimensional, fourier transform, time-of-flight MR angiography

    SciTech Connect

    Korogi, Yukunori; Takahashi, Mutsumasa; Mabuchi, Nobuhisa; Miki, Hitoshi; Fujiwara, Satoru; Horikawa, Yoshiharu; Nakagawa, Toshio; O`Uchi, Toshihiro; Watabe, Tsuneya; Shiga, Hayao

    1994-10-01

    To assess the accuracy of three-dimensional, Fourier transform, time-of-flight magnetic resonance (MR) angiography in the identification of intracranial aneurysms. MR angiograms of 126 patients (59 male and 67 female patients, aged 12-77 years) with various intracranial vascular lesions were evaluated. Seventy-eight aneurysms, including 60 less than 5 mm in diameter, in 61 patients were depicted at conventional angiography. Eight projection images, as well as one axial collapsed MR angiogram obtained with a maximum-intensity projection algorithm, were used for evaluation. Sensitivity for the five observers ranged from 58% to 68% (mean, 63%). Higher sensitivity was achieved for anterior communicating and middle cerebral artery aneurysms, while that for internal carotid artery aneurysms was poor. Sensitivities for small and medium aneurysms ranged from 50% to 60% (mean, 56%) and from 77% to 94% (mean, 85%), respectively. MR angiography can depict intracranial aneurysms 5 mm or larger with good accuracy but is less useful for the identification of smaller aneurysms. 12 refs., 5 figs., 5 tabs.

  16. More than accuracy: Nonverbal dialects modulate the time course of vocal emotion recognition across cultures.

    PubMed

    Jiang, Xiaoming; Paulmann, Silke; Robin, Jessica; Pell, Marc D

    2015-06-01

    Using a gating paradigm, this study investigated the nature of the in-group advantage in vocal emotion recognition by comparing 2 distinct cultures. Pseudoutterances conveying 4 basic emotions, expressed in English and Hindi, were presented to English and Hindi listeners. In addition to hearing full utterances, each stimulus was gated from its onset to construct 5 processing intervals to pinpoint when the in-group advantage emerges, and whether this differs when listening to a foreign language (English participants judging Hindi) or a second language (Hindi participants judging English). An index of the mean emotion identification point for each group and unbiased measures of accuracy at each time point was calculated. Results showed that in each language condition, native listeners were faster and more accurate than non-native listeners to recognize emotions. The in-group advantage emerged in both conditions after processing 400 ms to 500 ms of acoustic information. In the bilingual Hindi group, greater oral proficiency in English predicted faster and more accurate recognition of English emotional expressions. Consistent with dialect theory, our findings provide new evidence that nonverbal dialects impede both the accuracy and the efficiency of vocal emotion processing in cross-cultural settings, even when individuals are highly proficient in the out-group target language. PMID:25775176

  17. Relationship between changes in pupil size over time and diagnostic accuracy

    NASA Astrophysics Data System (ADS)

    Matsumoto, Toru; Furukawa, Akira; Tsuchikawa, Megumu; Fujino, Yuichi; Sone, Shusuke

    2003-05-01

    The objective of this study was to measure the image exploration activity of physicians, and thereby contribute to the development of a support system for CRT image interpretation in thoracic CT screening. In this study, we examined how the pupil diameters of five physicians changes over time during interpretation of a large quantity of CT images on a CRT monitor, and how this might be related to the accuracy of diagnosis. The study showed that, when a large quantity of CT images were viewed through a CRT monitor in a dimly lit room, the pupil diameter decreased during the second half of the long interpretation procedure in three of the five physicians. Furthermore, the pupil diameter frequently became approximately zero because the physician became drowsy. However, when the relationship between these phenomena and the accuracy of diagnosis was analyzed in one of the physicians, proof that such phenomena might lead to statistically significant false negatives or false positives was not found. Despite such results, the potential risk of misdiagnosis cannot be ignored. It may be necessary to devise both equipment and work conditions that will not cause the pupil diameter to become approximately zero during interpretation of images on a CRT monitor.

  18. Intrinsic Response Time of Graphene Photodetectors

    PubMed Central

    2011-01-01

    Graphene-based photodetectors are promising new devices for high-speed optoelectronic applications. However, despite recent efforts it is not clear what determines the ultimate speed limit of these devices. Here, we present measurements of the intrinsic response time of metal–graphene–metal photodetectors with monolayer graphene using an optical correlation technique with ultrashort laser pulses. We obtain a response time of 2.1 ps that is mainly given by the short lifetime of the photogenerated carriers. This time translates into a bandwidth of ∼262 GHz. Moreover, we investigate the dependence of the response time on gate voltage and illumination laser power. PMID:21627096

  19. High-accuracy and cost-effective photodiode spectral response measurement system

    NASA Astrophysics Data System (ADS)

    Chang, Gao-Wei; Liao, Chia-Cheng; Yeh, Zong-Mu

    2007-02-01

    With the rapid growth of optoelectronics technologies, photodiodes (PDs) has been widely used in optical measurement systems, color measurement and analysis systems, etc. To meet most of the measurement requirements, the determination of PD spectral responses is very important. The goal of this paper is to develop a high-accuracy and cost-effective spectral response measurement system for PDs. In this paper, the proposed system contains a grating-based spectral filtering module, an amplifier module, and a digital-signal-processing (DSP) based platform. In the spectral filtering module, a single-grating monochromator based on a Czerny-Turner configuration is first analyzed and simulated, and then the experiments are conducted to check if the measurement accuracy is satisfactory. In the measurement system, optoelectronic signals from the PD under test are acquired from the amplifier module and the DSP-based platform is developed to communicate and manipulate the measured data. Through comparison with the measurement data from a commercially available system, it is found that our approach gives quite satisfactory results.

  20. Effect of Variations in IRU Integration Time Interval On Accuracy of Aqua Attitude Estimation

    NASA Technical Reports Server (NTRS)

    Natanson, G. A.; Tracewell, Dave

    2003-01-01

    During Aqua launch support, attitude analysts noticed several anomalies in Onboard Computer (OBC) rates and in rates computed by the ground Attitude Determination System (ADS). These included: 1) periodic jumps in the OBC pitch rate every 2 minutes; 2) spikes in ADS pitch rate every 4 minutes; 3) close agreement between pitch rates computed by ADS and those derived from telemetered OBC quaternions (in contrast to the step-wise pattern observed for telemetered OBC rates); 4) spikes of +/- 10 milliseconds in telemetered IRU integration time every 4 minutes (despite the fact that telemetered time tags of any two sequential IRU measurements were always 1 second apart from each other). An analysis presented in the paper explains this anomalous behavior by a small average offset of about 0.5 +/- 0.05 microsec in the time interval between two sequential accumulated angle measurements. It is shown that errors in the estimated pitch angle due to neglecting the aforementioned variations in the integration time interval by the OBC is within +/- 2 arcseconds. Ground attitude solutions are found to be accurate enough to see the effect of the variations on the accuracy of the estimated pitch angle.

  1. Objective Error Criterion for Evaluation of Mapping Accuracy Based on Sensor Time-of-Flight Measurements

    PubMed Central

    Barshan, Billur

    2008-01-01

    An objective error criterion is proposed for evaluating the accuracy of maps of unknown environments acquired by making range measurements with different sensing modalities and processing them with different techniques. The criterion can also be used for the assessment of goodness of fit of curves or shapes fitted to map points. A demonstrative example from ultrasonic mapping is given based on experimentally acquired time-of-flight measurements and compared with a very accurate laser map, considered as absolute reference. The results of the proposed criterion are compared with the Hausdorff metric and the median error criterion results. The error criterion is sufficiently general and flexible that it can be applied to discrete point maps acquired with other mapping techniques and sensing modalities as well.

  2. Improving Accuracy in Arrhenius Models of Cell Death: Adding a Temperature-Dependent Time Delay.

    PubMed

    Pearce, John A

    2015-12-01

    The Arrhenius formulation for single-step irreversible unimolecular reactions has been used for many decades to describe the thermal damage and cell death processes. Arrhenius predictions are acceptably accurate for structural proteins, for some cell death assays, and for cell death at higher temperatures in most cell lines, above about 55 °C. However, in many cases--and particularly at hyperthermic temperatures, between about 43 and 55 °C--the particular intrinsic cell death or damage process under study exhibits a significant "shoulder" region that constant-rate Arrhenius models are unable to represent with acceptable accuracy. The primary limitation is that Arrhenius calculations always overestimate the cell death fraction, which leads to severely overoptimistic predictions of heating effectiveness in tumor treatment. Several more sophisticated mathematical model approaches have been suggested and show much-improved performance. But simpler models that have adequate accuracy would provide useful and practical alternatives to intricate biochemical analyses. Typical transient intrinsic cell death processes at hyperthermic temperatures consist of a slowly developing shoulder region followed by an essentially constant-rate region. The shoulder regions have been demonstrated to arise chiefly from complex functional protein signaling cascades that generate delays in the onset of the constant-rate region, but may involve heat shock protein activity as well. This paper shows that acceptably accurate and much-improved predictions in the simpler Arrhenius models can be obtained by adding a temperature-dependent time delay. Kinetic coefficients and the appropriate time delay are obtained from the constant-rate regions of the measured survival curves. The resulting predictions are seen to provide acceptably accurate results while not overestimating cell death. The method can be relatively easily incorporated into numerical models. Additionally, evidence is presented

  3. A Method for Evaluating Timeliness and Accuracy of Volitional Motor Responses to Vibrotactile Stimuli.

    PubMed

    Leineweber, Matthew J; Shi, Sam; Andrysek, Jan

    2016-01-01

    Artificial sensory feedback (ASF) systems can be used to compensate for lost proprioception in individuals with lower-limb impairments. Effective design of these ASF systems requires an in-depth understanding of how the parameters of specific feedback mechanism affect user perception and reaction to stimuli. This article presents a method for applying vibrotactile stimuli to human participants and measuring their response. Rotating mass vibratory motors are placed at pre-defined locations on the participant's thigh, and controlled through custom hardware and software. The speed and accuracy of participants' volitional responses to vibrotactile stimuli are measured for researcher-specified combinations of motor placement and vibration frequency. While the protocol described here uses push-buttons to collect a simple binary response to the vibrotactile stimuli, the technique can be extended to other response mechanisms using inertial measurement units or pressure sensors to measure joint angle and weight bearing ratios, respectively. Similarly, the application of vibrotactile stimuli can be explored for body segments other than the thigh. PMID:27585366

  4. Silicon Timing Response to Particles and Light

    SciTech Connect

    Ronzhin, Anatoly; Spiropulu, Maria

    2015-01-01

    It is observed growing interest to fast timing detectors in high energy physics, related, for example, with collider luminosity increase (LHC) [1]. The options of CMS [2] calorimeter upgrade based on silicon detectors renewed interest to the timing study of this type of detectors. The article is devoted to study of silicon timing response to particles and light.

  5. Estimating subsurface water volumes and transit times in Hokkaido river catchments, Japan, using high-accuracy tritium analysis

    NASA Astrophysics Data System (ADS)

    Gusyev, Maksym; Yamazaki, Yusuke; Morgenstern, Uwe; Stewart, Mike; Kashiwaya, Kazuhisa; Hirai, Yasuyuki; Kuribayashi, Daisuke; Sawano, Hisaya

    2015-04-01

    The goal of this study is to estimate subsurface water transit times and volumes in headwater catchments of Hokkaido, Japan, using the New Zealand high-accuracy tritium analysis technique. Transit time provides insights into the subsurface water storage and therefore provides a robust and quick approach to quantifying the subsurface groundwater volume. Our method is based on tritium measurements in river water. Tritium is a component of meteoric water, decays with a half-life of 12.32 years, and is inert in the subsurface after the water enters the groundwater system. Therefore, tritium is ideally suited for characterization of the catchment's responses and can provide information on mean water transit times up to 200 years. Only in recent years has it become possible to use tritium for dating of stream and river water, due to the fading impact of the bomb-tritium from thermo-nuclear weapons testing, and due to improved measurement accuracy for the extremely low natural tritium concentrations. Transit time of the water discharge is one of the most crucial parameters for understanding the response of catchments and estimating subsurface water volume. While many tritium transit time studies have been conducted in New Zealand, only a limited number of tritium studies have been conducted in Japan. In addition, the meteorological, orographic and geological conditions of Hokkaido Island are similar to those in parts of New Zealand, allowing for comparison between these regions. In 2014, three field trips were conducted in Hokkaido in June, July and October to sample river water at river gauging stations operated by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT). These stations have altitudes between 36 m and 860 m MSL and drainage areas between 45 and 377 km2. Each sampled point is located upstream of MLIT dams, with hourly measurements of precipitation and river water levels enabling us to distinguish between the snow melt and baseflow contributions

  6. Time-dependent classification accuracy curve under marker-dependent sampling

    PubMed Central

    Zhu, Zhaoyin; Wang, Xiaofei; Saha-Chaudhuri, Paramita; Kosinski, Andrzej S.; George, Stephen L.

    2016-01-01

    Evaluating the classification accuracy of a candidate biomarker signaling the onset of disease or disease status is essential for medical decision making. A good biomarker would accurately identify the patients who are likely to progress or die at a particular time in the future or who are in urgent need for active treatments. To assess the performance of a candidate biomarker, the receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC) are commonly used. In many cases, the standard simple random sampling (SRS) design used for biomarker validation studies is costly and inefficient. In order to improve the efficiency and reduce the cost of biomarker validation, marker-dependent sampling (MDS) may be used. In a MDS design, the selection of patients to assess true survival time is dependent on the result of a biomarker assay. In this article, we introduce a nonparametric estimator for time-dependent AUC under a MDS design. The consistency and the asymptotic normality of the proposed estimator is established. Simulation shows the unbiasedness of the proposed estimator and a significant efficiency gain of the MDS design over the SRS design. PMID:27119599

  7. Time-dependent classification accuracy curve under marker-dependent sampling.

    PubMed

    Zhu, Zhaoyin; Wang, Xiaofei; Saha-Chaudhuri, Paramita; Kosinski, Andrzej S; George, Stephen L

    2016-07-01

    Evaluating the classification accuracy of a candidate biomarker signaling the onset of disease or disease status is essential for medical decision making. A good biomarker would accurately identify the patients who are likely to progress or die at a particular time in the future or who are in urgent need for active treatments. To assess the performance of a candidate biomarker, the receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC) are commonly used. In many cases, the standard simple random sampling (SRS) design used for biomarker validation studies is costly and inefficient. In order to improve the efficiency and reduce the cost of biomarker validation, marker-dependent sampling (MDS) may be used. In a MDS design, the selection of patients to assess true survival time is dependent on the result of a biomarker assay. In this article, we introduce a nonparametric estimator for time-dependent AUC under a MDS design. The consistency and the asymptotic normality of the proposed estimator is established. Simulation shows the unbiasedness of the proposed estimator and a significant efficiency gain of the MDS design over the SRS design. PMID:27119599

  8. High-accuracy time- and space-resolved Stark shift measurements

    SciTech Connect

    Bailey, J.E.; Adams, R.; Carlson, A.L.; Ching, C.H.; Filuk, A.B.; Lake, P.

    1996-07-01

    Stark-shift measurements using emission spectroscopy are a powerful tool for advancing understanding in many plasma physics experiments. The authors use simultaneous 2-D-spatial and time-resolved spectra to study the electric field evolution in the 20 TW Particle Beam Fusion Accelerator II ion diode acceleration gap. Fiber optic arrays transport light from the gap to remote streaked spectrographs operated in a multiplexed mode that enables recording time-resolved spectra from eight spatial locations on a single instrument. Design optimization and characterization measurements of the multiplexed spectrograph properties include the astigmatism, resolution, dispersion variation, and sensitivity. A semi-automated line-fitting procedure determines the Stark shift and the related uncertainties. Fields up to 10 MV/cm are measured with an accuracy {+-}2--4%. Detailed tests of the fitting procedure confirm that the wavelength shift uncertainties are accurate to better than {+-}20%. Development of an active spectroscopy probe technique that uses laser-induced fluorescence from an injected atomic beam to obtain 3-D space- and time-resolved measurements of the electric and magnetic fields is in progress.

  9. Accuracy of History, Wheezing, and Forced Expiratory Time in the Diagnosis of Chronic Obstructive Pulmonary Disease

    PubMed Central

    Straus, Sharon E; McAlister, Finlay A; Sackett, David L; Deeks, Jonathan J

    2002-01-01

    OBJECTIVE To determine the accuracy of the history and selected elements of the physical examination in the diagnosis of chronic obstructive pulmonary disease (COPD). DESIGN Independent blind comparison of the standard clinical examination (evaluating the accuracy of history, wheezing, and forced expiratory time [FET]) with spirometry. The gold standard for diagnosis of COPD was a forced expiratory volume at 1 second (FEV1) below the fifth percentile (adjusted for patient height and age). SETTING Seven sites in 6 countries, including investigators from primary care and secondary care settings. PARTICIPANTS One hundred sixty-one consecutive patients with varying severity of disease (known COPD, suspected COPD, or no COPD) participated in the study. MAIN RESULTS One hundred sixty-one patients (mean age 65 years, 39% female, 41% with known COPD, 27% with suspected COPD, and 32% normal) were recruited. Mean (±SD) FEV1 and forced vital capacity were 1,720 (±830) mL and 2,520 (±970) mL. The likelihood ratios (LR) for the tested elements of the clinical examination (and their P values on χ2 testing) were: self-reported history of COPD, 5.6 (P < .001); FET greater than 9 seconds, 6.7 (P < 0.01); smoked longer than 40 pack years, 3.3 (P = .001); wheezing, 4.0 (P < .001); male gender, 1.6 (P < .001); and age over 65 years, 1.6 (P = .025). The accuracy of these elements was not appreciably different when reference standards other than FEV1 below the 5th percentile were applied. Only 3 elements of the clinical examination were significantly associated with the diagnosis of COPD on multivariate analysis: self-reported history of COPD (adjusted LR 4.4), wheezing (adjusted LR 2.9), and FET greater than 9 seconds (adjusted LR 4.6). Area under the receiver operating characteristic curve for the model incorporating these 3 factors was 0.86. CONCLUSIONS Less emphasis should be placed on the presence of isolated symptoms or signs in the diagnosis of COPD. While numerous elements

  10. Response time for multilayered platinum resistance thermometers

    NASA Technical Reports Server (NTRS)

    Pandey, D. K.; Ash, R. L.

    1985-01-01

    Response time constants for several multilayered temperature transducers were determined numerically by using Martin Marietta's MITAS software package which is available at NASA Langley Research Center. Present results were found in close agreement with the solutions reported in the literature, thus, the capability of MITAS was justified. On the basis of experiences gained, the MITAS is recommended for use in predicting the response time constants of sensors by an in-situ technique.

  11. The Value of Response Times in Item Response Modeling

    ERIC Educational Resources Information Center

    Molenaar, Dylan

    2015-01-01

    A new and very interesting approach to the analysis of responses and response times is proposed by Goldhammer (this issue). In his approach, differences in the speed-ability compromise within respondents are considered to confound the differences in ability between respondents. These confounding effects of speed on the inferences about ability can…

  12. Vehicle Position Estimation Based on Magnetic Markers: Enhanced Accuracy by Compensation of Time Delays

    PubMed Central

    Byun, Yeun-Sub; Jeong, Rag-Gyo; Kang, Seok-Won

    2015-01-01

    The real-time recognition of absolute (or relative) position and orientation on a network of roads is a core technology for fully automated or driving-assisted vehicles. This paper presents an empirical investigation of the design, implementation, and evaluation of a self-positioning system based on a magnetic marker reference sensing method for an autonomous vehicle. Specifically, the estimation accuracy of the magnetic sensing ruler (MSR) in the up-to-date estimation of the actual position was successfully enhanced by compensating for time delays in signal processing when detecting the vertical magnetic field (VMF) in an array of signals. In this study, the signal processing scheme was developed to minimize the effects of the distortion of measured signals when estimating the relative positional information based on magnetic signals obtained using the MSR. In other words, the center point in a 2D magnetic field contour plot corresponding to the actual position of magnetic markers was estimated by tracking the errors between pre-defined reference models and measured magnetic signals. The algorithm proposed in this study was validated by experimental measurements using a test vehicle on a pilot network of roads. From the results, the positioning error was found to be less than 0.04 m on average in an operational test. PMID:26580622

  13. Well-posedness and accuracy of the ensemble Kalman filter in discrete and continuous time

    NASA Astrophysics Data System (ADS)

    Kelly, D. T. B.; Law, K. J. H.; Stuart, A. M.

    2014-10-01

    The ensemble Kalman filter (EnKF) is a method for combining a dynamical model with data in a sequential fashion. Despite its widespread use, there has been little analysis of its theoretical properties. Many of the algorithmic innovations associated with the filter, which are required to make a useable algorithm in practice, are derived in an ad hoc fashion. The aim of this paper is to initiate the development of a systematic analysis of the EnKF, in particular to do so for small ensemble size. The perspective is to view the method as a state estimator, and not as an algorithm which approximates the true filtering distribution. The perturbed observation version of the algorithm is studied, without and with variance inflation. Without variance inflation well-posedness of the filter is established; with variance inflation accuracy of the filter, with respect to the true signal underlying the data, is established. The algorithm is considered in discrete time, and also for a continuous time limit arising when observations are frequent and subject to large noise. The underlying dynamical model, and assumptions about it, is sufficiently general to include the Lorenz '63 and '96 models, together with the incompressible Navier-Stokes equation on a two-dimensional torus. The analysis is limited to the case of complete observation of the signal with additive white noise. Numerical results are presented for the Navier-Stokes equation on a two-dimensional torus for both complete and partial observations of the signal with additive white noise.

  14. Do missing data influence the accuracy of divergence-time estimation with BEAST?

    PubMed

    Zheng, Yuchi; Wiens, John J

    2015-04-01

    Time-calibrated phylogenies have become essential to evolutionary biology. A recurrent and unresolved question for dating analyses is whether genes with missing data cells should be included or excluded. This issue is particularly unclear for the most widely used dating method, the uncorrelated lognormal approach implemented in BEAST. Here, we test the robustness of this method to missing data. We compare divergence-time estimates from a nearly complete dataset (20 nuclear genes for 32 species of squamate reptiles) to those from subsampled matrices, including those with 5 or 2 complete loci only and those with 5 or 8 incomplete loci added. In general, missing data had little impact on estimated dates (mean error of ∼5Myr per node or less, given an overall age of ∼220Myr in squamates), even when 80% of sampled genes had 75% missing data. Mean errors were somewhat higher when all genes were 75% incomplete (∼17Myr). However, errors increased dramatically when only 2 of 9 fossil calibration points were included (∼40Myr), regardless of missing data. Overall, missing data (and even numbers of genes sampled) may have only minor impacts on the accuracy of divergence dating with BEAST, relative to the dramatic effects of fossil calibrations. PMID:25681677

  15. Vehicle Position Estimation Based on Magnetic Markers: Enhanced Accuracy by Compensation of Time Delays.

    PubMed

    Byun, Yeun-Sub; Jeong, Rag-Gyo; Kang, Seok-Won

    2015-01-01

    The real-time recognition of absolute (or relative) position and orientation on a network of roads is a core technology for fully automated or driving-assisted vehicles. This paper presents an empirical investigation of the design, implementation, and evaluation of a self-positioning system based on a magnetic marker reference sensing method for an autonomous vehicle. Specifically, the estimation accuracy of the magnetic sensing ruler (MSR) in the up-to-date estimation of the actual position was successfully enhanced by compensating for time delays in signal processing when detecting the vertical magnetic field (VMF) in an array of signals. In this study, the signal processing scheme was developed to minimize the effects of the distortion of measured signals when estimating the relative positional information based on magnetic signals obtained using the MSR. In other words, the center point in a 2D magnetic field contour plot corresponding to the actual position of magnetic markers was estimated by tracking the errors between pre-defined reference models and measured magnetic signals. The algorithm proposed in this study was validated by experimental measurements using a test vehicle on a pilot network of roads. From the results, the positioning error was found to be less than 0.04 m on average in an operational test. PMID:26580622

  16. Numerical Experiment with Time and Spatial Accuracy of Navier-Stokes Computation For Helicopter Problems

    NASA Technical Reports Server (NTRS)

    Ahmad, Jasim; Aiken, Edwin, W. (Technical Monitor)

    1998-01-01

    Helicopter flowfields are highly unsteady, nonlinear and three-dimensional. In forward flight and in hover, the rotor blades interact with the tip vortex and wake sheet developed by either itself or the other blades. This interaction, known as blade-vortex interactions (BVI), results in unsteady loading of the blades and can cause a distinctive acoustic signature. Accurate and cost-effective computational fluid dynamic solutions that capture blade-vortex interactions can help rotor designers and engineers to predict rotor performance and to develop designs for low acoustic signature. Such a predictive method must preserve a blade's shed vortex for several blade revolutions before being dissipated. A number of researchers have explored the requirements for this task. This paper will outline some new capabilities that have been added to the NASA Ames' OVERFLOW code to improve its overall accuracy for both vortex capturing and unsteady flows. To highlight these improvements, a number of case studies will be presented. These case studies consist of free convection of a 2-dimensional vortex, dynamically pitching 2-D airfoil including light-stall, and a full 3-D unsteady viscous solution of a helicopter rotor in forward flight In this study both central and upwind difference schemes are modified to be more accurate. Central difference scheme is chosen for this simulation because the flowfield is not dominated by strong shocks. The feature of shock-vortex interaction in such a flow is less important than the dominant blade-vortex interaction. The scheme is second-order accurate in time and solves the thin-layer Navier-Stokes equations in fully-implicit manner at each time-step. The spatial accuracy is either second and fourth-order central difference or third-order upwind difference using Roe-flux and MUSCLE scheme. This paper will highlight and demonstrate the methods for several sample cases and for a helicopter rotor. Preliminary computations on a rotor were performed

  17. Hierarchical Bayes Models for Response Time Data

    ERIC Educational Resources Information Center

    Craigmile, Peter F.; Peruggia, Mario; Van Zandt, Trisha

    2010-01-01

    Human response time (RT) data are widely used in experimental psychology to evaluate theories of mental processing. Typically, the data constitute the times taken by a subject to react to a succession of stimuli under varying experimental conditions. Because of the sequential nature of the experiments there are trends (due to learning, fatigue,…

  18. Validating the Accuracy of Reaction Time Assessment on Computer-Based Tablet Devices.

    PubMed

    Schatz, Philip; Ybarra, Vincent; Leitner, Donald

    2015-08-01

    Computer-based assessment has evolved to tablet-based devices. Despite the availability of tablets and "apps," there is limited research validating their use. We documented timing delays between stimulus presentation and (simulated) touch response on iOS devices (3rd- and 4th-generation Apple iPads) and Android devices (Kindle Fire, Google Nexus, Samsung Galaxy) at response intervals of 100, 250, 500, and 1,000 milliseconds (ms). Results showed significantly greater timing error on Google Nexus and Samsung tablets (81-97 ms), than Kindle Fire and Apple iPads (27-33 ms). Within Apple devices, iOS 7 obtained significantly lower timing error than iOS 6. Simple reaction time (RT) trials (250 ms) on tablet devices represent 12% to 40% error (30-100 ms), depending on the device, which decreases considerably for choice RT trials (3-5% error at 1,000 ms). Results raise implications for using the same device for serial clinical assessment of RT using tablets, as well as the need for calibration of software and hardware. PMID:25612627

  19. Impact of heart disease and calibration interval on accuracy of pulse transit time-based blood pressure estimation.

    PubMed

    Ding, Xiaorong; Zhang, Yuanting; Tsang, Hon Ki

    2016-02-01

    Continuous blood pressure (BP) measurement without a cuff is advantageous for the early detection and prevention of hypertension. The pulse transit time (PTT) method has proven to be promising for continuous cuffless BP measurement. However, the problem of accuracy is one of the most challenging aspects before the large-scale clinical application of this method. Since PTT-based BP estimation relies primarily on the relationship between PTT and BP under certain assumptions, estimation accuracy will be affected by cardiovascular disorders that impair this relationship and by the calibration frequency, which may violate these assumptions. This study sought to examine the impact of heart disease and the calibration interval on the accuracy of PTT-based BP estimation. The accuracy of a PTT-BP algorithm was investigated in 37 healthy subjects and 48 patients with heart disease at different calibration intervals, namely 15 min, 2 weeks, and 1 month after initial calibration. The results showed that the overall accuracy of systolic BP estimation was significantly lower in subjects with heart disease than in healthy subjects, but diastolic BP estimation was more accurate in patients than in healthy subjects. The accuracy of systolic and diastolic BP estimation becomes less reliable with longer calibration intervals. These findings demonstrate that both heart disease and the calibration interval can influence the accuracy of PTT-based BP estimation and should be taken into consideration to improve estimation accuracy. PMID:26767518

  20. Response Latency as a Predictor of the Accuracy of Children's Reports

    ERIC Educational Resources Information Center

    Ackerman, Rakefet; Koriat, Asher

    2011-01-01

    Researchers have explored various diagnostic cues to the accuracy of information provided by child eyewitnesses. Previous studies indicated that children's confidence in their reports predicts the relative accuracy of these reports, and that the confidence-accuracy relationship generally improves as children grow older. In this study, we examined…

  1. Accuracy of Perceived Estimated Travel Time by EMS to a Trauma Center in San Bernardino County, California

    PubMed Central

    Neeki, Michael M.; MacNeil, Colin; Toy, Jake; Dong, Fanglong; Vara, Richard; Powell, Joe; Pennington, Troy; Kwong, Eugene

    2016-01-01

    Introduction Mobilization of trauma resources has the potential to cause ripple effects throughout hospital operations. One major factor affecting efficient utilization of trauma resources is a discrepancy between the prehospital estimated time of arrival (ETA) as communicated by emergency medical services (EMS) personnel and their actual time of arrival (TOA). The current study aimed to assess the accuracy of the perceived prehospital estimated arrival time by EMS personnel in comparison to their actual arrival time at a Level II trauma center in San Bernardino County, California. Methods This retrospective study included traumas classified as alerts or activations that were transported to Arrowhead Regional Medical Center in 2013. We obtained estimated arrival time and actual arrival time for each transport from the Surgery Department Trauma Registry. The difference between the median of ETA and actual TOA by EMS crews to the trauma center was calculated for these transports. Additional variables assessed included time of day and month during which the transport took place. Results A total of 2,454 patients classified as traumas were identified in the Surgery Department Trauma Registry. After exclusion of trauma consults, walk-ins, handoffs between agencies, downgraded traumas, traumas missing information, and traumas transported by agencies other than American Medical Response, Ontario Fire, Rialto Fire or San Bernardino County Fire, we included a final sample size of 555 alert and activation classified traumas in the final analysis. When combining all transports by the included EMS agencies, the median of the ETA was 10 minutes and the median of the actual TOA was 22 minutes (median of difference=9 minutes, p<0.0001). Furthermore, when comparing the difference between trauma alerts and activations, trauma activations demonstrated an equal or larger difference in the median of the estimated and actual time of arrival (p<0.0001). We also found month and time of

  2. Accuracy and speed of response to different voice types in a cockpit voice warning system

    NASA Astrophysics Data System (ADS)

    Freedman, J.; Rumbaugh, W. A.

    1983-09-01

    Voice warning systems (VWS) in aircraft cockpits provide a valuable means of warning identification. Improvements in technology have made the VWS a viable addition to aircraft warning systems. This thesis was an experiment to determine the best voice type (male, female, or neutral machine) for use in a VWS for military aircraft. Different levels of engine background noise, signal to noise ratio of the warning message, and precursor delivery formats were used. The experiment had ten subjects performing a primary tracking task; at random intervals a voice warning was interjected, requiring that the subjects respond by pushing the correct button. The results of this experiment contradict some previous beliefs and findings. The male voice was associated with more accurate responses for voice warning systems in the military aircraft environment. For speed of response the results were more complicated; the male voice was generally more closely associated with faster response times for accurate responses.

  3. Parsing the phonological loop: activation timing in the dorsal speech stream determines accuracy in speech reproduction.

    PubMed

    Herman, Alexander B; Houde, John F; Vinogradov, Sophia; Nagarajan, Srikantan S

    2013-03-27

    Despite significant research and important clinical correlates, direct neural evidence for a phonological loop linking speech perception, short-term memory and production remains elusive. To investigate these processes, we acquired whole-head magnetoencephalographic (MEG) recordings from human subjects performing a variable-length syllable sequence reproduction task. The MEG sensor data were source localized using a time-frequency optimized spatially adaptive filter, and we examined the time courses of cortical oscillatory power and the correlations of oscillatory power with behavior between onset of the audio stimulus and the overt speech response. We found dissociations between time courses of behaviorally relevant activations in a network of regions falling primarily within the dorsal speech stream. In particular, verbal working memory load modulated high gamma power in both Sylvian-parietal-temporal and Broca's areas. The time courses of the correlations between high gamma power and subject performance clearly alternated between these two regions throughout the task. Our results provide the first evidence of a reverberating input-output buffer system in the dorsal stream underlying speech sensorimotor integration, consistent with recent phonological loop, competitive queuing, and speech-motor control models. These findings also shed new light on potential sources of speech dysfunction in aphasia and neuropsychiatric disorders, identifying anatomically and behaviorally dissociable activation time windows critical for successful speech reproduction. PMID:23536060

  4. Remote real-time monitoring of free flaps via smartphone photography and 3G wireless Internet: a prospective study evidencing diagnostic accuracy.

    PubMed

    Engel, Holger; Huang, Jung Ju; Tsao, Chung Kan; Lin, Chia-Yu; Chou, Pan-Yu; Brey, Eric M; Henry, Steven L; Cheng, Ming Huei

    2011-11-01

    This prospective study was designed to compare the accuracy rate between remote smartphone photographic assessments and in-person examinations for free flap monitoring. One hundred and three consecutive free flaps were monitored with in-person examinations and assessed remotely by three surgeons (Team A) via photographs transmitted over smartphone. Four other surgeons used the traditional in-person examinations as Team B. The response time to re-exploration was defined as the interval between when a flap was evaluated as compromised by the nurse/house officer and when the decision was made for re-exploration. The accuracy rate was 98.7% and 94.2% for in-person and smartphone photographic assessments, respectively. The response time of 8 ± 3 min in Team A was statistically shorter than the 180 ± 104 min in Team B (P = 0.01 by the Mann-Whitney test). The remote smartphone photography assessment has a comparable accuracy rate and shorter response time compared with in-person examination for free flap monitoring. PMID:22072583

  5. 29 CFR 1610.9 - Responses: timing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Responses: timing. 1610.9 Section 1610.9 Labor Regulations Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION AVAILABILITY OF RECORDS Production or... reasonably be expected to pose an imminent threat to the life or physical safety of an individual; or...

  6. RESPONSE TIMES IN DECISION-MAKING TASKS.

    ERIC Educational Resources Information Center

    DAGLE, EVERETT F.; AND OTHERS

    THE HUMAN OPERATOR AFFECTS TOTAL PERFORMANCE OF SEMI-AUTOMATED SYSTEMS, BUT LITTLE IS KNOWN ABOUT HIS SOURCES OF ERROR, PARTICULARLY WITH RESPECT TO RESPONSE TIME. UNDER CONTROLLED LABORATORY CONDITIONS, 37 FRESHMEN AND SOPHOMORE GIRLS ATTENDING JUNIOR COLLEGE WERE ASKED TO GUESS A SERIES OF RANDOM NUMBERS GENERATED BY AN ELECTROMECHANICAL SYSTEM…

  7. A Ballistic Model of Choice Response Time

    ERIC Educational Resources Information Center

    Brown, Scott; Heathcote, Andrew

    2005-01-01

    Almost all models of response time (RT) use a stochastic accumulation process. To account for the benchmark RT phenomena, researchers have found it necessary to include between-trial variability in the starting point and/or the rate of accumulation, both in linear (R. Ratcliff & J. N. Rouder, 1998) and nonlinear (M. Usher & J. L. McClelland, 2001)…

  8. Investigation of response time testing requirements

    SciTech Connect

    Swisher, V.I. ); Mayo, C.W. ); Weiss, J. )

    1991-05-01

    The purpose of the Response Time Testing (RTT) Program was to determine if requirements for RTT could be eliminated for specific pressure and differential pressure transmitters and switches. This program was initiated when experience and historical data from a significant number of nuclear power plants indicated that, while RTT is both resource and exposure intensive, an insignificant number of pressure sensor failures have been detected through this type of testing. Assessment of plant response time data and performance of Failure Modes and Effects Analysis (FMEA) on sensor hardware were the mechanisms used by the program to determine the redundancy of RTT in conjunction with other required periodic testing (e.g., calibrations, channel checks, surveillance tests). In general, the FMEA results indicated RTT is redundant to other periodic tests. Results of the program identified only two response time failure modes and two manufacturing/handling defects that may not concurrently affect sensor output. The two failure modes affect a limited number of sensor models. Appropriate testing has been identified in cases where response time degradation may not be coincident with significant sensor output change. 14 refs., 19 figs., 39 tabs.

  9. Creating Responsive Schools: Contextualizing Early Warning, Timely Response.

    ERIC Educational Resources Information Center

    Dwyer, Kevin P.; Osher, David; Hoffman, Catherine C.

    2000-01-01

    Discussion of the Department of Education's 1998 publication, "Early Warning, Timely Response: A Guide to Safe Schools," stresses the importance of violence prevention by providing a supportive schoolwide climate and responding early to at-risk students' academic and behavioral problems. Early imminent warning signs are highlighted, as are…

  10. Patterns of Response Times and Response Choices to Science Questions: The Influence of Relative Processing Time

    ERIC Educational Resources Information Center

    Heckler, Andrew F.; Scaife, Thomas M.

    2015-01-01

    We report on five experiments investigating response choices and response times to simple science questions that evoke student "misconceptions," and we construct a simple model to explain the patterns of response choices. Physics students were asked to compare a physical quantity represented by the slope, such as speed, on simple physics…

  11. Real-time diagnosis of H. pylori infection during endoscopy: Accuracy of an innovative tool (EndoFaster)

    PubMed Central

    Costamagna, Guido; Zullo, Angelo; Bizzotto, Alessandra; Hassan, Cesare; Riccioni, Maria Elena; Marmo, Clelia; Strangio, Giuseppe; Di Rienzo, Teresa Antonella; Cammarota, Giovanni; Gasbarrini, Antonio; Repici, Alessandro

    2015-01-01

    Background EndoFaster is novel device able to perform real-time ammonium measurement in gastric juice allowing H. pylori diagnosis during endoscopy. This large study aimed to validate the accuracy of EndoFaster for real-time H. pylori detection. Methods Consecutive patients who underwent upper endoscopy in two centres were prospectively enrolled. During endoscopy, 4 ml of gastric juice were aspirated to perform automatic analysis by EndoFaster within 90 seconds, and H. pylori was considered present (>62 ppm/ml) or absent (≤62 ppm/ml). Accuracy was measured by using histology as gold standard, and 13C-urea breath test (UBT) in discordant cases. Accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) were calculated. Results Overall, 189 patients were enrolled, but in seven (3.4%) the aspirated gastric juice amount was insufficient to perform the test. The accuracy, sensitivity, specificity, PPV, and NPV were 87.4%, 90.3%, 85.5%, 80.2%, 93.1%, respectively, and 92.6%, 97.1%, 89.7%, 85.9%, 98.0%, respectively, when H. pylori status was reclassified according to the UBT result in discordant cases. Conclusions This study found a high accuracy/feasibility of EndoFaster for real-time H. pylori diagnosis. Use of EndoFaster may allow selecting those patients in whom routine gastric biopsies could be avoided.

  12. Structural health monitoring ultrasonic thickness measurement accuracy and reliability of various time-of-flight calculation methods

    NASA Astrophysics Data System (ADS)

    Eason, Thomas J.; Bond, Leonard J.; Lozev, Mark G.

    2016-02-01

    The accuracy, precision, and reliability of ultrasonic thickness structural health monitoring systems are discussed in-cluding the influence of systematic and environmental factors. To quantify some of these factors, a compression wave ultrasonic thickness structural health monitoring experiment is conducted on a flat calibration block at ambient temperature with forty four thin-film sol-gel transducers and various time-of-flight thickness calculation methods. As an initial calibration, the voltage response signals from each sensor are used to determine the common material velocity as well as the signal offset unique to each calculation method. Next, the measurement precision of the thickness error of each method is determined with a proposed weighted censored relative maximum likelihood analysis technique incorporating the propagation of asymmetric measurement uncertainty. The results are presented as upper and lower confidence limits analogous to the a90/95 terminology used in industry recognized Probability-of-Detection assessments. Future work is proposed to apply the statistical analysis technique to quantify measurement precision of various thickness calculation methods under different environmental conditions such as high temperature, rough back-wall surface, and system degradation with an intended application to monitor naphthenic acid corrosion in oil refineries.

  13. Method and apparatus for measuring response time

    DOEpatents

    Johanson, Edward W.; August, Charles

    1985-01-01

    A method of measuring the response time of an electrical instrument which generates an output signal in response to the application of a specified input, wherein the output signal varies as a function of time and when subjected to a step input approaches a steady-state value, comprises the steps of: (a) applying a step input of predetermined value to the electrical instrument to generate an output signal; (b) simultaneously starting a timer; (c) comparing the output signal to a reference signal to generate a stop signal when the output signal is substantially equal to the reference signal, the reference signal being a specified percentage of the steady-state value of the output signal corresponding to the predetermined value of the step input; and (d) applying the stop signal when generated to stop the timer.

  14. Method and apparatus for measuring response time

    DOEpatents

    Johanson, E.W.; August, C.

    1983-08-11

    A method of measuring the response time of an electrical instrument which generates an output signal in response to the application of a specified input, wherein the output signal varies as a function of time and when subjected to a step input approaches a steady-state value, comprises the steps of: (a) applying a step input of predetermined value to the electrical instrument to generate an output signal; (b) simultaneously starting a timer; (c) comparing the output signal to a reference signal to generate a stop signal when the output signal is substantially equal to the reference signal, the reference signal being a specified percentage of the steady-state value of the output signal corresponding to the predetermined value of the step input; and (d) applying the stop signal when generated to stop the timer.

  15. Binocular summation and peripheral visual response time

    NASA Technical Reports Server (NTRS)

    Gilliland, K.; Haines, R. F.

    1975-01-01

    Six males were administered a peripheral visual response time test to the onset of brief small stimuli imaged in 10-deg arc separation intervals across the dark adapted horizontal retinal meridian under both binocular and monocular viewing conditions. This was done in an attempt to verify the existence of peripheral binocular summation using a response time measure. The results indicated that from 50-deg arc right to 50-deg arc left of the line of sight binocular summation is a reasonable explanation for the significantly faster binocular data. The stimulus position by viewing eye interaction was also significant. A discussion of these and other analyses is presented along with a review of related literature.

  16. A quantitative method for evaluating numerical simulation accuracy of time-transient Lamb wave propagation with its applications to selecting appropriate element size and time step.

    PubMed

    Wan, Xiang; Xu, Guanghua; Zhang, Qing; Tse, Peter W; Tan, Haihui

    2016-01-01

    Lamb wave technique has been widely used in non-destructive evaluation (NDE) and structural health monitoring (SHM). However, due to the multi-mode characteristics and dispersive nature, Lamb wave propagation behavior is much more complex than that of bulk waves. Numerous numerical simulations on Lamb wave propagation have been conducted to study its physical principles. However, few quantitative studies on evaluating the accuracy of these numerical simulations were reported. In this paper, a method based on cross correlation analysis for quantitatively evaluating the simulation accuracy of time-transient Lamb waves propagation is proposed. Two kinds of error, affecting the position and shape accuracies are firstly identified. Consequently, two quantitative indices, i.e., the GVE (group velocity error) and MACCC (maximum absolute value of cross correlation coefficient) derived from cross correlation analysis between a simulated signal and a reference waveform, are proposed to assess the position and shape errors of the simulated signal. In this way, the simulation accuracy on the position and shape is quantitatively evaluated. In order to apply this proposed method to select appropriate element size and time step, a specialized 2D-FEM program combined with the proposed method is developed. Then, the proper element size considering different element types and time step considering different time integration schemes are selected. These results proved that the proposed method is feasible and effective, and can be used as an efficient tool for quantitatively evaluating and verifying the simulation accuracy of time-transient Lamb wave propagation. PMID:26315506

  17. Response time correlations for platinum resistance thermometers

    NASA Technical Reports Server (NTRS)

    Pandey, D. K.; Ash, R. L.; Dillon-Townes, L. A.

    1985-01-01

    The 'plunge method' recommended by ASTM has been used to determine the time constant of 100-ohm platinum resistance thermometers (PRT) considered for use in the National Transonic Facility. It is shown that the response time of ventilated PRT can be correlated with the reciprocal of the heat transfer coefficient in a given field. Universal correlations are established for the 100- and 1000-ohm PRT with uncertainties of 20 and 30 percent, respectively. The correlations are found to be consistent with the uncertainty involved in heat transfer correlations available in the literature and are recommended for use in flowing liquids and gases.

  18. Real-time, high-accuracy 3D imaging and shape measurement.

    PubMed

    Nguyen, Hieu; Nguyen, Dung; Wang, Zhaoyang; Kieu, Hien; Le, Minh

    2015-01-01

    In spite of the recent advances in 3D shape measurement and geometry reconstruction, simultaneously achieving fast-speed and high-accuracy performance remains a big challenge in practice. In this paper, a 3D imaging and shape measurement system is presented to tackle such a challenge. The fringe-projection-profilometry-based system employs a number of advanced approaches, such as: composition of phase-shifted fringe patterns, externally triggered synchronization of system components, generalized system setup, ultrafast phase-unwrapping algorithm, flexible system calibration method, robust gamma correction scheme, multithread computation and processing, and graphics-processing-unit-based image display. Experiments have shown that the proposed system can acquire and display high-quality 3D reconstructed images and/or video stream at a speed of 45 frames per second with relative accuracy of 0.04% or at a reduced speed of 22.5 frames per second with enhanced accuracy of 0.01%. The 3D imaging and shape measurement system shows great promise of satisfying the ever-increasing demands of scientific and engineering applications. PMID:25967028

  19. Time accuracy of a radio frequency identification patient tracking system for recording operating room timestamps.

    PubMed

    Marjamaa, Riitta A; Torkki, Paulus M; Torkki, Markus I; Kirvelä, Olli A

    2006-04-01

    A patient tracking system is a promising tool for managing patient flow and improving efficiency in the operating room. Wireless location systems, using infrared or radio frequency transmitters, can automatically timestamp key events, thereby decreasing the need for manual data input. In this study, we measured the accuracy and precision of automatically documented timestamps compared with manual recording. Each patient scheduled for urgent surgery was given an active radio frequency/infrared transmitter. The prototype software tracked the patient throughout the perioperative process, automatically documenting the timestamps. Both automatic and traditional data entry were compared with the reference data. The absolute value of median error was 64% smaller (P < 0.01), and the average quartile deviation of error was 69% smaller in automatic documentation. The average delay between an activity and the documentation was 80 seconds in automatic documentation and 735 seconds in manual documentation. Both the accuracy and the precision were better in automatic documentation and the data were immediately available. Automatic documentation with the Indoor Positioning System can help in managing patient flow and in increasing transparency with faster availability and better accuracy of data. PMID:16551921

  20. Tracking Accuracy of a Real-Time Fiducial Tracking System for Patient Positioning and Monitoring in Radiation Therapy

    SciTech Connect

    Shchory, Tal; Schifter, Dan; Lichtman, Rinat; Neustadter, David; Corn, Benjamin W.

    2010-11-15

    Purpose: In radiation therapy there is a need to accurately know the location of the target in real time. A novel radioactive tracking technology has been developed to answer this need. The technology consists of a radioactive implanted fiducial marker designed to minimize migration and a linac mounted tracking device. This study measured the static and dynamic accuracy of the new tracking technology in a clinical radiation therapy environment. Methods and Materials: The tracking device was installed on the linac gantry. The radioactive marker was located in a tissue equivalent phantom. Marker location was measured simultaneously by the radioactive tracking system and by a Microscribe G2 coordinate measuring machine (certified spatial accuracy of 0.38 mm). Localization consistency throughout a volume and absolute accuracy in the Fixed coordinate system were measured at multiple gantry angles over volumes of at least 10 cm in diameter centered at isocenter. Dynamic accuracy was measured with the marker located inside a breathing phantom. Results: The mean consistency for the static source was 0.58 mm throughout the tested region at all measured gantry angles. The mean absolute position error in the Fixed coordinate system for all gantry angles was 0.97 mm. The mean real-time tracking error for the dynamic source within the breathing phantom was less than 1 mm. Conclusions: This novel radioactive tracking technology has the potential to be useful in accurate target localization and real-time monitoring for radiation therapy.

  1. Regulating emotions uniquely modifies reaction time, rate of force production, and accuracy of a goal-directed motor action.

    PubMed

    Beatty, Garrett F; Fawver, Bradley; Hancock, Gabriella M; Janelle, Christopher M

    2014-02-01

    We investigated how emotion regulation (ER) strategies influence the execution of a memory guided, ballistic pinch grip. Participants (N=33) employed ER strategies (expressive suppression, emotional expression, and attentional deployment) while viewing emotional stimuli (IAPS images). Upon stimulus offset, participants produced a targeted pinch force aimed at 10% of their maximum voluntary contraction. Performance measures included reaction time (RT), rate of force production, and performance accuracy. As hypothesized, attentional deployment resulted in the slowest RT, largest rate of force production, and poorest performance accuracy. In contrast, expressive suppression reduced the rate of force production and increased performance accuracy relative to emotional expression and attentional deployment. Findings provide evidence that emotion regulation strategies uniquely influence human movement. Future work should further delineate the interacting role that emotion regulation strategies have in modulating both affective experience and motor performance. PMID:24576703

  2. Performance-Based Cognitive Screening Instruments: An Extended Analysis of the Time versus Accuracy Trade-off

    PubMed Central

    Larner, Andrew J.

    2015-01-01

    Early and accurate diagnosis of dementia is key to appropriate treatment and management. Clinical assessment, including the use of cognitive screening instruments, remains integral to the diagnostic process. Many cognitive screening instruments have been described, varying in length and hence administration time, but it is not known whether longer tests offer greater diagnostic accuracy than shorter tests. Data from several pragmatic diagnostic test accuracy studies examining various cognitive screening instruments in a secondary care setting were analysed to correlate measures of test diagnostic accuracy and test duration, building on the findings of a preliminary study. High correlations which were statistically significant were found between one measure of diagnostic accuracy, area under the receiver operating characteristic curve, and surrogate measures of test duration, namely total test score and total number of test items/questions. Longer cognitive screening instruments may offer greater accuracy for the diagnosis of dementia, an observation which has possible implications for the optimal organisation of dedicated cognitive disorders clinics. PMID:26854168

  3. Patterns of response times and response choices to science questions: the influence of relative processing time.

    PubMed

    Heckler, Andrew F; Scaife, Thomas M

    2015-04-01

    We report on five experiments investigating response choices and response times to simple science questions that evoke student "misconceptions," and we construct a simple model to explain the patterns of response choices. Physics students were asked to compare a physical quantity represented by the slope, such as speed, on simple physics graphs. We found that response times of incorrect answers, resulting from comparing heights, were faster than response times of correct answers comparing slopes. This result alone might be explained by the fact that height was typically processed faster than slope for this kind of task, which we confirmed in a separate experiment. However, we hypothesize that the difference in response time is an indicator of the cause (rather than the result) of the response choice. To support this, we found that imposing a 3-s delay in responding increased the number of students comparing slopes (answering correctly) on the task. Additionally a significant proportion of students recognized the correct written rule (compare slope), but on the graph task they incorrectly compared heights. Finally, training either with repetitive examples or providing a general rule both improved scores, but only repetitive examples had a large effect on response times, thus providing evidence of dual paths or processes to a solution. Considering models of heuristics, information accumulation models, and models relevant to the Stroop effect, we construct a simple relative processing time model that could be viewed as a kind of fluency heuristic. The results suggest that misconception-like patterns of answers to some science questions commonly found on tests may be explained in part by automatic processes that involve the relative processing time of considered dimensions and a priority to answer quickly. PMID:25230833

  4. Fourth-grade Children’s Dietary Recall Accuracy is Influenced by Retention Interval (Target Period and Interview Time)

    PubMed Central

    Hardin, James W.; Guinn, Caroline H.; Royer, Julie A.; Mackelprang, Alyssa J.; Smith, Albert F.

    2009-01-01

    Background For a 24-hour dietary recall, two possible target periods are the prior 24 hours (24 hours immediately preceding the interview time) and previous day (midnight to midnight of the day before the interview), and three possible interview times are morning, afternoon, and evening. Target period and interview time determine the retention interval (elapsed time between to-be-reported meals and the interview), which, along with intervening meals, can influence reporting accuracy. Objective The effects of target period and interview time on children’s accuracy for reporting school meals during 24-hour dietary recalls were investigated. Design and subjects/setting During the 2004–05, 2005–06, and 2006–07 school years in (city), (state), each of 374 randomly selected fourth-grade children (96% Black) was observed eating two consecutive school meals (breakfast, lunch) and interviewed to obtain a 24-hour dietary recall using one of six conditions defined by crossing two target periods with three interview times. Each condition had 62 or 64 children (half boys). Main outcome measures Accuracy for reporting school meals was quantified by calculating rates for omissions (food items observed eaten but unreported) and intrusions (food items reported eaten but unobserved); a measure of total inaccuracy combined errors for reporting food items and amounts. Statistical analyses performed For each accuracy measure, analysis of variance was conducted with target period, interview time, their interaction, sex, interviewer, and school year in the model. Results There was a target-period effect and a target-period by interview-time interaction on omission rates, intrusion rates, and total inaccuracy (six P values <0.004). For prior-24-hour recalls compared to previous-day recalls, and for prior-24-hour recalls in the afternoon and evening compared to previous-day recalls in the afternoon and evening, omission rates were better by one-third, intrusion rates were better by

  5. Accuracy and Variability in Response Methods Used to Determine Object Location Knowledge in the Blind.

    ERIC Educational Resources Information Center

    Haber, Lyn; Haber, Ralph N.

    1992-01-01

    This study evaluated the accuracy of 9 pointing methods used by 20 blind adults. Substantial differences were found, with the most accurate methods involving a body part or extension. The verbal "clockface" was the least accurate and most variable method. The long cane is recommended as a pointing method for adults in applied and research…

  6. Residential Real-time Price Response Simulation

    SciTech Connect

    Widergren, Steven E.; Subbarao, Krishnappa; Chassin, David P.; Fuller, Jason C.; Pratt, Robert G.

    2011-10-10

    The electric industry is gaining experience with innovative price responsive demand pilots and limited roll-outs to customers. One of these pilots is investigating real-time pricing signals to engage end-use systems and local distributed generation and storage in a distributed optimization process. Attractive aspects about the approach include strong scalability characteristics, simplified interfaces between automation devices, and the adaptability to integrate a wide variety of devices and systems. Experience in this nascent field is revealing a rich array of for engineering decisions and the application of complexity theory. To test the decisions, computer simulations are used to reveal insights about design, demand elasticity, and the limits of response (including consumer fatigue). Agent-based approaches lend themselves well in the simulation to modeling the participation and interaction of each piece of equipment on a distribution feeder. This paper discusses rate design and simulation experiences at the distribution feeder level where consumers and their HVAC systems and water heaters on a feeder receive real-time pricing signals.

  7. Method to improve the blade tip-timing accuracy of fiber bundle sensor under varying tip clearance

    NASA Astrophysics Data System (ADS)

    Duan, Fajie; Zhang, Jilong; Jiang, Jiajia; Guo, Haotian; Ye, Dechao

    2016-01-01

    Blade vibration measurement based on the blade tip-timing method has become an industry-standard procedure. Fiber bundle sensors are widely used for tip-timing measurement. However, the variation of clearance between the sensor and the blade will bring a tip-timing error to fiber bundle sensors due to the change in signal amplitude. This article presents methods based on software and hardware to reduce the error caused by the tip clearance change. The software method utilizes both the rising and falling edges of the tip-timing signal to determine the blade arrival time, and a calibration process suitable for asymmetric tip-timing signals is presented. The hardware method uses an automatic gain control circuit to stabilize the signal amplitude. Experiments are conducted and the results prove that both methods can effectively reduce the impact of tip clearance variation on the blade tip-timing and improve the accuracy of measurements.

  8. Unstructured grids in 3D and 4D for a time-dependent interface in front tracking with improved accuracy

    SciTech Connect

    Glimm, J.; Grove, J. W.; Li, X. L.; Li, Y.; Xu, Z.

    2002-01-01

    Front tracking traces the dynamic evolution of an interface separating differnt materials or fluid components. In this paper, they describe three types of the grid generation methods used in the front tracking method. One is the unstructured surface grid. The second is a structured grid-based reconstruction method. The third is a time-space grid, also grid based, for a conservative tracking algorithm with improved accuracy.

  9. Accuracy Study of the Space-Time CE/SE Method for Computational Aeroacoustics Problems Involving Shock Waves

    NASA Technical Reports Server (NTRS)

    Wang, Xiao Yen; Chang, Sin-Chung; Jorgenson, Philip C. E.

    1999-01-01

    The space-time conservation element and solution element(CE/SE) method is used to study the sound-shock interaction problem. The order of accuracy of numerical schemes is investigated. The linear model problem.govemed by the 1-D scalar convection equation, sound-shock interaction problem governed by the 1-D Euler equations, and the 1-D shock-tube problem which involves moving shock waves and contact surfaces are solved to investigate the order of accuracy of numerical schemes. It is concluded that the accuracy of the CE/SE numerical scheme with designed 2nd-order accuracy becomes 1st order when a moving shock wave exists. However, the absolute error in the CE/SE solution downstream of the shock wave is on the same order as that obtained using a fourth-order accurate essentially nonoscillatory (ENO) scheme. No special techniques are used for either high-frequency low-amplitude waves or shock waves.

  10. Accuracy of a Mitral Valve Segmentation Method Using J-Splines for Real-Time 3D Echocardiography Data

    PubMed Central

    Siefert, Andrew W.; Icenogle, David A.; Rabbah, Jean-Pierre; Saikrishnan, Neelakantan; Rossignac, Jarek; Lerakis, Stamatios; Yoganathan, Ajit P.

    2013-01-01

    Patient-specific models of the heart’s mitral valve (MV) exhibit potential for surgical planning. While advances in 3D echocardiography (3DE) have provided adequate resolution to extract MV leaflet geometry, no study has quantitatively assessed the accuracy of their modeled leaflets versus a ground-truth standard for temporal frames beyond systolic closure or for differing valvular dysfunctions. The accuracy of a 3DE-based segmentation methodology based on J-splines was assessed for porcine MVs with known 4D leaflet coordinates within a pulsatile simulator during closure, peak closure, and opening for a control, prolapsed, and billowing MV model. For all time points, the mean distance error between the segmented models and ground-truth data were 0.40±0.32 mm, 0.52±0.51 mm, and 0.74±0.69 mm for the control, flail, and billowing models. For all models and temporal frames, 95% of the distance errors were below 1.64 mm. When applied to a patient data set, segmentation was able to confirm a regurgitant orifice and post-operative improvements in coaptation. This study provides an experimental platform for assessing the accuracy of an MV segmentation methodology at phases beyond systolic closure and for differing MV dysfunctions. Results demonstrate the accuracy of a MV segmentation methodology for the development of future surgical planning tools. PMID:23460042

  11. Effect of Time Lapse on the Diagnostic Accuracy of Cone Beam Computed Tomography for Detection of Vertical Root Fractures.

    PubMed

    Eskandarloo, Amir; Asl, Amin Mahdavi; Jalalzadeh, Mohsen; Tayari, Maryam; Hosseinipanah, Mohammad; Fardmal, Javad; Shokri, Abbas

    2016-01-01

    Accurate and early diagnosis of vertical root fractures (VRFs) is imperative to prevent extensive bone loss and unnecessary endodontic and prosthodontic treatments. The aim of this study was to assess the effect of time lapse on the diagnostic accuracy of cone beam computed tomography (CBCT) for VRFs in endodontically treated dog's teeth. Forty-eight incisors and premolars of three adult male dogs underwent root canal therapy. The teeth were assigned to two groups: VRFs were artificially induced in the first group (n=24) while the teeth in the second group remained intact (n=24). The CBCT scans were obtained by NewTom 3G unit immediately after inducing VRFs and after one, two, three, four, eight, 12 and 16 weeks. Three oral and maxillofacial radiologists blinded to the date of radiographs assessed the presence/absence of VRFs on CBCT scans. The sensitivity, specificity and accuracy values were calculated and data were analyzed using SPSS v.16 software and ANOVA. The total accuracy of detection of VRFs immediately after surgery, one, two, three, four, eight, 12 and 16 weeks was 67.3%, 68.7%, 66.6%, 64.6%, 64.5%, 69.4%, 68.7%, 68% respectively. The effect of time lapse on detection of VRFs was not significant (p>0.05). Overall sensitivity, specificity and accuracy of CBCT for detection of VRFs were 74.3%, 62.2%, 67.2% respectively. Cone beam computed tomography is a valuable tool for detection of VRFs. Time lapse (four months) had no effect on detection of VRFs on CBCT scans. PMID:27007339

  12. Time-response-based evolutionary optimization

    NASA Astrophysics Data System (ADS)

    Avigad, Gideon; Goldvard, Alex; Salomon, Shaul

    2015-04-01

    Solutions to engineering problems are often evaluated by considering their time responses; thus, each solution is associated with a function. To avoid optimizing the functions, such optimization is usually carried out by setting auxiliary objectives (e.g. minimal overshoot). Therefore, in order to find different optimal solutions, alternative auxiliary optimization objectives may have to be defined prior to optimization. In the current study, a new approach is suggested that avoids the need to define auxiliary objectives. An algorithm is suggested that enables the optimization of solutions according to their transient behaviours. For this optimization, the functions are sampled and the problem is posed as a multi-objective problem. The recently introduced algorithm NSGA-II-PSA is adopted and tailored to solve it. Mathematical as well as engineering problems are utilized to explain and demonstrate the approach and its applicability to real life problems. The results highlight the advantages of avoiding the definition of artificial objectives.

  13. Precise and Continuous Time and Frequency Synchronisation at the 5×10-19 Accuracy Level

    PubMed Central

    Wang, B.; Gao, C.; Chen, W. L.; Miao, J.; Zhu, X.; Bai, Y.; Zhang, J. W.; Feng, Y. Y.; Li, T. C.; Wang, L. J.

    2012-01-01

    The synchronisation of time and frequency between remote locations is crucial for many important applications. Conventional time and frequency dissemination often makes use of satellite links. Recently, the communication fibre network has become an attractive option for long-distance time and frequency dissemination. Here, we demonstrate accurate frequency transfer and time synchronisation via an 80 km fibre link between Tsinghua University (THU) and the National Institute of Metrology of China (NIM). Using a 9.1 GHz microwave modulation and a timing signal carried by two continuous-wave lasers and transferred across the same 80 km urban fibre link, frequency transfer stability at the level of 5×10−19/day was achieved. Time synchronisation at the 50 ps precision level was also demonstrated. The system is reliable and has operated continuously for several months. We further discuss the feasibility of using such frequency and time transfer over 1000 km and its applications to long-baseline radio astronomy. PMID:22870385

  14. Response time correlations for platinum resistance thermometers in flowing fluids

    NASA Technical Reports Server (NTRS)

    Pandey, D. K.; Ash, R. L.

    1985-01-01

    The thermal response of two types of Platinum Resistance Thermometers (PRT's), which are being considered for use in the National Transonic Wind Tunnel Facility, were studied. Response time correlations for each PRT, in flowing water, oil and air, were established separately. A universal correlation, tau WOA = 2.0 + 1264, 9/h, for a Hy-Cal Sensor (with a reference resistance of 100 ohm) within an error of 20% was established while the universal correlation for the Rosemount Sensor (with a reference resistance of 1000 ohm), tau OA = 0.122 + 1105.6/h, was found with a maximum percentage error of 30%. The correlation for the Rosemount Sensor was based on air and oil data only which is certainly not sufficient to make a correlation applicable to every condition. Therefore, the correlation needs more data to be gathered in different fluids. Also, it is necessary to state that the calculation of the parameter, h, was based on the available heat transfer correlations, whose accuracies are already reported in literature uncertain within 20-30%. Therefore, the universal response constant correlations established here for the Hy-Cal and Rosemount sensors are consistent with the uncertainty in the input data and are recommended for future use in flowing liquids and gases.

  15. Accuracy study of time delay estimation techniques in laser pulse ranger

    NASA Astrophysics Data System (ADS)

    Yang, Jinliang; Wang, Xingshu; Gao, Yang

    2013-12-01

    Time-of-flight measurement by using laser pulses is an alternative method in laser range finding and laser scanning, the echo pulses originating from backscattering of the emitted laser pulse on targets is detected by optical receiver. The distance of target can be obtained by measuring the round-trip time. Time-of-arrival estimation may be based on schemes such as constant-fraction discriminator (CFD) in analog electronics. In contrast, as sampled signals are available, time delay estimation may be based on schemes like direct cross-correlation function (CCF) and average square difference function (ASDF) in digital electronics. By the way, constant-fraction discriminator can also be used in digital electronics. All this three methods are analyzed and compared with each other. It is shown that estimators based on CCF and ASDF are more precise than conventional CFD based estimator.

  16. Combining Reaction Time and Accuracy: The Relationship Between Working Memory Capacity and Task Switching as a Case Example.

    PubMed

    Draheim, Christopher; Hicks, Kenny L; Engle, Randall W

    2016-01-01

    It is generally agreed upon that the mechanisms underlying task switching heavily depend on working memory, yet numerous studies have failed to show a strong relationship between working memory capacity (WMC) and task-switching ability. We argue that this relationship does indeed exist but that the dependent variable used to measure task switching is problematic. To support our claim, we reanalyzed data from two studies with a new scoring procedure that combines reaction time (RT) and accuracy into a single score. The reanalysis revealed a strong relationship between task switching and WMC that was not present when RT-based switch costs were used as the dependent variable. We discuss the theoretical implications of this finding along with the potential uses and limitations of the scoring procedure we used. More broadly, we emphasize the importance of using measures that incorporate speed and accuracy in other areas of research, particularly in comparisons of subjects differing in cognitive and developmental levels. PMID:26817730

  17. A novel mask proximity correction software combining accuracy and reduced writing time for the manufacturing of advanced photomasks

    NASA Astrophysics Data System (ADS)

    Schiavone, Patrick; Martin, Luc; Browning, Clyde; Farys, Vincent; Sundermann, Frank; Narukawa, Shogo; Takikawa, Tadahiko; Hayashi, Naoya

    2012-06-01

    The new generations of photomasks are seen to bring more and more challenges to the mask manufacturer. Maskshops face two conflicting requirements, namely improving pattern fidelity and reducing or at least maintaining acceptable writing time. These requirements are getting more and more challenging since pattern size continuously shrinks and data volumes continuously grows. Although the classical dose modulation Proximity Effect Correction is able to provide sufficient process control to the mainstream products, an increased number of published and wafer data show that the mask process is becoming a nonnegligible contributor to the 28nm technology yield. We will show in this paper that a novel approach of mask proximity effect correction is able to meet the dual challenge of the new generation of masks. Unlike the classical approach, the technique presented in this paper is based on a concurrent optimization of the dose and geometry of the fractured shots. Adding one more parameter allows providing the best possible compromise between accuracy and writing time since energy latitude can be taken into account as well. This solution is implemented in the Inscale software package from Aselta Nanographics. We have assessed the capability of this technology on several levels of a 28nm technology. On this set, the writing time has been reduced up to 25% without sacrificing the accuracy which at the same time has been improved significantly compared to the existing process. The experiments presented in the paper confirm that a versatile proximity effect correction strategy, combining dose and geometry modulation helps the users to tradeoff between resolution/accuracy and e-beam write time.

  18. Reduced temporal sampling effect on accuracy of time-domain fluorescence lifetime Förster resonance energy transfer

    PubMed Central

    Omer, Travis; Zhao, Lingling; Intes, Xavier; Hahn, Juergen

    2014-01-01

    Abstract. Fluorescence lifetime imaging (FLIM) aims at quantifying the exponential decay rate of fluorophores to yield lifetime maps over the imaged sample. When combined with Förster resonance energy transfer (FRET), the technique can be used to indirectly sense interactions at the nanoscale such as protein–protein interactions, protein–DNA interactions, and protein conformational changes. In the case of FLIM-FRET, the fluorescence intensity decays are fitted to a biexponential model in order to estimate the lifetime and fractional amplitude coefficients of each component of the population of the donor fluorophore (quenched and nonquenched). Numerous time data points, also called temporal or time gates, are typically employed for accurately estimating the model parameters, leading to lengthy acquisition times and significant computational demands. This work investigates the effect of the number and location of time gates on model parameter estimation accuracy. A detailed model of a FLIM-FRET imaging system is used for the investigation, and the simulation outcomes are validated with in vitro and in vivo experimental data. In all cases investigated, it is found that 10 equally spaced time gates allow robust estimation of model-based parameters with accuracy similar to that of full temporal datasets (90 gates). PMID:25166472

  19. Joint Modeling of Ability and Differential Speed Using Responses and Response Times.

    PubMed

    Fox, Jean-Paul; Marianti, Sukaesi

    2016-01-01

    With computerized testing, it is possible to record both the responses of test takers to test questions (i.e., items) and the amount of time spent by a test taker in responding to each question. Various models have been proposed that take into account both test-taker ability and working speed, with the many models assuming a constant working speed throughout the test. The constant working speed assumption may be inappropriate for various reasons. For example, a test taker may need to adjust the pace due to time mismanagement, or a test taker who started out working too fast may reduce the working speed to improve accuracy. A model is proposed here that allows for variable working speed. An illustration of the model using the Amsterdam Chess Test data is provided. PMID:27269482

  20. Accuracy of an UWB-based position tracking system used for time-motion analyses in game sports.

    PubMed

    Leser, Roland; Schleindlhuber, Armin; Lyons, Keith; Baca, Arnold

    2014-01-01

    The main aim of this study was to determine the accuracy of the ultra-wideband (UWB)-based positioning system Ubisense, which is used for time-motion analysis in sports. Furthermore, some alternatives for positioning the system's transponders on the atheletes, as well as the accuracy depending on the location of measurement, were tested. Therefore, in a pre-study, some basic issues were examined (measurement assumptions and consistency and location of the system's transponder used for position detection), and position measurements at the borders and in the centre of a basketball field were performed. In the main study, 13 male basketball players (15.8 years ± 0.6; 187.9 height ± 3.4; 77.5 weight ± 3.7), equipped with a Ubisense transponder mounted on top of their heads, handled a trundle wheel during simulated match play. The players with the trundle wheel participated passively in the match by following one of the ten competing players. The distance measurements of the trundle wheel were used as reference values and compared to the Ubisense distance estimations. Best results were found with the measurements of a single mounted transponder on top of the athlete's heads. No differences were detectable in the accuracy between measurements in the centre and at the borders of the basketball field. The (Ubisense) system's difference to the (trundle wheel) reference was 3.45 ± 1.99%, resulting in 95% limits of agreement of -0.46-7.35%. The study indicates the examined system's sufficient accuracy for time-motion analysis in basketball. PMID:24512176

  1. Accuracy of patient's turnover time prediction using RFID technology in an academic ambulatory surgery center.

    PubMed

    Marchand-Maillet, Florence; Debes, Claire; Garnier, Fanny; Dufeu, Nicolas; Sciard, Didier; Beaussier, Marc

    2015-02-01

    Patients flow in outpatient surgical unit is a major issue with regards to resource utilization, overall case load and patient satisfaction. An electronic Radio Frequency Identification Device (RFID) was used to document the overall time spent by the patients between their admission and discharge from the unit. The objective of this study was to evaluate how a RFID-based data collection system could provide an accurate prediction of the actual time for the patient to be discharged from the ambulatory surgical unit after surgery. This is an observational prospective evaluation carried out in an academic ambulatory surgery center (ASC). Data on length of stay at each step of the patient care, from admission to discharge, were recorded by a RFID device and analyzed according to the type of surgical procedure, the surgeon and the anesthetic technique. Based on these initial data (n = 1520), patients were scheduled in a sequential manner according to the expected duration of the previous case. The primary endpoint was the difference between actual and predicted time of discharge from the unit. A total of 414 consecutive patients were prospectively evaluated. One hundred seventy four patients (42%) were discharged at the predicted time ± 30 min. Only 24% were discharged behind predicted schedule. Using an automatic record of patient's length of stay would allow an accurate prediction of the discharge time according to the type of surgery, the surgeon and the anesthetic procedure. PMID:25637542

  2. Diagnostic accuracy of MRI to evaluate tumour response and residual tumour size after neoadjuvant chemotherapy in breast cancer patients

    PubMed Central

    Acea, Benigno; Soler, Rafaela; Iglesias, Ángela; Santiago, Paz; Mosquera, Joaquín; Calvo, Lourdes; Seoane-Pillado, Teresa; García, Alejandra

    2016-01-01

    Background The aim, of the study was to estimate the accuracy of magnetic resonance imaging (MRI) in assessing residual disease in breast cancer patients receiving neoadjuvant chemotherapy (NAC) and to identify the clinico-pathological factors that affect the diagnostic accuracy of breast MRI to determine residual tumour size following NAC. Patients and methods 91 breast cancer patients undergoing NAC (92 breast lesions) were included in the study. Breast MRI was performed at baseline and after completion of NAC. Treatment response was evaluated by MRI and histopathological examination to investigate the ability of MRI to predict tumour response. Residual tumour size was measured on post-treatment MRI and compared with pathology in 89 lesions. Clinicopathological factors were analyzed to compare MRI-pathologic size differences. Results The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for diagnosing invasive residual disease by using MRI were 75.00%, 78.57%, 88.89%, 57.89%, and 76.09% respectively. The Pearson’s correlation coefficient (r) between tumour sizes determined by MRI and pathology was r = 0.648 (p < 0.001). The size discrepancy was significantly lower in cancers with initial MRI size ≤ 5 cm (p = 0.050), in cancers with high tumour grade (p < 0.001), and in patients with hormonal receptor-negative cancer (p = 0.033). Conclusions MRI is an accurate tool for evaluating tumour response after NAC. The accuracy of MRI in estimating residual tumour size varies with the baseline MRI tumour size, the tumour grade and the hormonal receptor status. PMID:27069452

  3. Method and computer product to increase accuracy of time-based software verification for sensor networks

    DOEpatents

    Foo Kune, Denis; Mahadevan, Karthikeyan

    2011-01-25

    A recursive verification protocol to reduce the time variance due to delays in the network by putting the subject node at most one hop from the verifier node provides for an efficient manner to test wireless sensor nodes. Since the software signatures are time based, recursive testing will give a much cleaner signal for positive verification of the software running on any one node in the sensor network. In this protocol, the main verifier checks its neighbor, who in turn checks its neighbor, and continuing this process until all nodes have been verified. This ensures minimum time delays for the software verification. Should a node fail the test, the software verification downstream is halted until an alternative path (one not including the failed node) is found. Utilizing techniques well known in the art, having a node tested twice, or not at all, can be avoided.

  4. The effect of S-wave arrival times on the accuracy of hypocenter estimation

    USGS Publications Warehouse

    Gomberg, J.S.; Shedlock, K.M.; Roecker, S.W.

    1990-01-01

    We have examined the theoretical basis behind some of the widely accepted "rules of thumb' for obtaining accurate hypocenter estimates that pertain to the use of S phases and illustrate, in a variety of ways, why and when these "rules' are applicable. Most methods used to determine earthquake hypocenters are based on iterative, linearized, least-squares algorithms. We examine the influence of S-phase arrival time data on such algorithms by using the program HYPOINVERSE with synthetic datasets. We conclude that a correctly timed S phase recorded within about 1.4 focal depth's distance from the epicenter can be a powerful constraint on focal depth. Furthermore, we demonstrate that even a single incorrectly timed S phase can result in depth estimates and associated measures of uncertainty that are significantly incorrect. -from Authors

  5. Accuracy and stability of time-split finite-difference schemes

    NASA Technical Reports Server (NTRS)

    Dwoyer, D. L.; Thames, F. C.

    1981-01-01

    In a recently published work by Abarbanel and Gottlieb (1980), a new class of explicit time-split algorithms designed for application to the compressible Navier-Stokes equations was developed. These algorithms, which utilize locally-one-dimensional (LOD) spatial steps, were shown to possess stability characteristics superior to those of other time-split schemes. In the present work, the properties of an implicit LOD method, analogous to the Abarbanel-Gottlieb algorithm, are examined using the two-dimensional heat conduction equation as the test problem. Both temporal and spatial inconsistencies inherent in the scheme are identified, and a new consistent, implicit splitting approach is developed and applied to the linear Burgers' equation. The relationship between this new method and other time-split implicit schemes is explained and stability problems encountered with the method in three dimensions are discussed.

  6. Comparison of Clinician Judgments and Measurements of Swallow Response Time: A Preliminary Report

    ERIC Educational Resources Information Center

    Karnell, Michael P.; Rogus, Nicole M.

    2005-01-01

    Practicing clinicians frequently offer judgments about aspects of swallowing physiology rather than performing actual measurements. Little is known about the accuracy of those judgments. The purpose of this preliminary study was to explore agreement of clinicians' judgments of pharyngeal swallow response time (PSRT) with temporal measurements of…

  7. Toward Submillimeter Accuracy in the Management of Intrafraction Motion: The Integration of Real-Time Internal Position Monitoring and Multileaf Collimator Target Tracking

    SciTech Connect

    Sawant, Amit Smith, Ryan L.; Venkat, Raghu B.; Santanam, Lakshmi; Cho, Byungchul; Poulsen, Per; Cattell, Herbert; Newell, Laurence J.; Parikh, Parag; Keall, Paul J.

    2009-06-01

    Purpose: We report on an integrated system for real-time adaptive radiation delivery to moving tumors. The system combines two promising technologies-three-dimensional internal position monitoring using implanted electromagnetically excitable transponders and corresponding real-time beam adaptation using a dynamic multileaf collimator (DMLC). Methods and Materials: In a multi-institutional academic and industrial collaboration, a research version of the Calypso position monitoring system was integrated with a DMLC-based four-dimensional intensity-modulated radiotherapy delivery system using a Varian 120-leaf multileaf collimator (MLC). Two important determinants of system performance-latency (i.e., elapsed time between target motion and MLC response) and geometric accuracy-were investigated. Latency was quantified by acquiring continuous megavoltage X-ray images of a moving phantom (with embedded transponders) that was tracked in real time by a circular MLC field. The latency value was input into a motion prediction algorithm within the DMLC tracking system. Geometric accuracy was calculated as the root-mean-square positional error between the target and the centroid of the MLC aperture for patient-derived three-dimensional motion trajectories comprising two lung tumor traces and one prostate trace. Results: System latency was determined to be approximately 220 milliseconds. Tracking accuracy was observed to be sub-2 mm for the respiratory motion traces and sub-1 mm for prostate motion. Conclusion: We have developed and characterized a research version of a novel four-dimensional delivery system that integrates nonionizing radiation-based internal position monitoring and accurate real-time DMLC-based beam adaptation. This system represents a significant step toward achieving the eventual goal of geometrically ideal dose delivery to moving tumors.

  8. State-based metacognition: how time of day affects the accuracy of metamemory.

    PubMed

    Hourihan, Kathleen L; Benjamin, Aaron S

    2014-01-01

    Although there is an abundance of research on how stimulus characteristics and encoding conditions affect metamemory, and how those effects either do or do not mirror effects on memory, there is little research on whether and how characteristics of participants' states-like mood, fatigue, or hunger-affect metamemory. The present study examined whether metamemory ability fluctuates with time of day. Specifically, we evaluated whether learners can successfully account for the effects of time of day on their memory, and whether metacognitive monitoring is more accurate at an individual's optimal time of day. Young adults studied and recalled lists of words in both the morning and the afternoon, providing various metamemory judgements during each test session. We replicated the finding that young participants recalled more words in the afternoon than in the morning. Prior to study, participants did not predict superior recall in the afternoon, but they did after they had an opportunity to study the list (but before the test on that material). We also found that item-by-item predictions were more accurate in the afternoon, suggesting that self-regulated learning might benefit from being scheduled during times of day that accord with individuals' peak arousal. PMID:23742008

  9. Repeating a Monologue under Increasing Time Pressure: Effects on Fluency, Complexity, and Accuracy

    ERIC Educational Resources Information Center

    Thai, Chau; Boers, Frank

    2016-01-01

    Studies have shown that learners' task performance improves when they have the opportunity to repeat the task. Conditions for task repetition vary, however. In the 4/3/2 activity, learners repeat a monologue under increasing time pressure. The purpose is to foster fluency, but it has been suggested in the literature that it also benefits other…

  10. There Is Time for Calculation in Speed Chess, and Calculation Accuracy Increases With Expertise.

    PubMed

    Chang, Yu-Hsuan A; Lane, David M

    2016-01-01

    The recognition-action theory of chess skill holds that expertise in chess is due primarily to the ability to recognize familiar patterns of pieces. Despite its widespread acclaim, empirical evidence for this theory is indirect. One source of indirect evidence is that there is a high correlation between speed chess and standard chess. Assuming that there is little or no time for calculation in speed chess, this high correlation implies that calculation is not the primary factor in standard chess. Two studies were conducted analyzing 100 games of speed chess. In Study 1, we examined the distributions of move times, and the key finding was that players often spent considerable time on a few moves. Moreover, stronger players were more likely than weaker players to do so. Study 2 examined skill differences in calculation by examining poor moves. The stronger players made proportionally fewer blunders (moves that a 2-ply search would have revealed to be errors). Overall, the poor moves made by the weaker players would have required a less extensive search to be revealed as poor moves than the poor moves made by the stronger players. Apparently, the stronger players are searching deeper and more accurately. These results are difficult to reconcile with the view that speed chess does not allow players time to calculate extensively and call into question the assertion that the high correlation between speed chess and standard chess supports recognition-action theory. PMID:27029102

  11. Monitoring Rater Performance over Time: A Framework for Detecting Differential Accuracy and Differential Scale Category Use

    ERIC Educational Resources Information Center

    Myford, Carol M.; Wolfe, Edward W.

    2009-01-01

    In this study, we describe a framework for monitoring rater performance over time. We present several statistical indices to identify raters whose standards drift and explain how to use those indices operationally. To illustrate the use of the framework, we analyzed rating data from the 2002 Advanced Placement English Literature and Composition…

  12. Design and analysis of ALE schemes with provable second-order time-accuracy for inviscid and viscous flow simulations

    NASA Astrophysics Data System (ADS)

    Geuzaine, Philippe; Grandmont, Céline; Farhat, Charbel

    2003-10-01

    We consider the solution of inviscid as well as viscous unsteady flow problems with moving boundaries by the arbitrary Lagrangian-Eulerian (ALE) method. We present two computational approaches for achieving formal second-order time-accuracy on moving grids. The first approach is based on flux time-averaging, and the second one on mesh configuration time-averaging. In both cases, we prove that formally second-order time-accurate ALE schemes can be designed. We illustrate our theoretical findings and highlight their impact on practice with the solution of inviscid as well as viscous, unsteady, nonlinear flow problems associated with the AGARD Wing 445.6 and a complete F-16 configuration.

  13. A Flexible Latent Trait Model for Response Times in Tests

    ERIC Educational Resources Information Center

    Ranger, Jochen; Kuhn, Jorg-Tobias

    2012-01-01

    Latent trait models for response times in tests have become popular recently. One challenge for response time modeling is the fact that the distribution of response times can differ considerably even in similar tests. In order to reduce the need for tailor-made models, a model is proposed that unifies two popular approaches to response time…

  14. Accuracy of Single Frequency GPS Observations Processing In Near Real-time With Use of Code Predicted Products

    NASA Astrophysics Data System (ADS)

    Wielgosz, P. A.

    In this year, the system of active geodetic GPS permanent stations is going to be estab- lished in Poland. This system should provide GPS observations for a wide spectrum of users, especially it will be a great opportunity for surveyors. Many of surveyors still use cheaper, single frequency receivers. This paper focuses on processing of single frequency GPS observations only. During processing of such observations the iono- sphere plays an important role, so we concentrated on the influence of the ionosphere on the positional coordinates. Twenty consecutive days of GPS data from 2001 year were processed to analyze the accuracy of a derived three-dimensional relative vec- tor position between GPS stations. Observations from two Polish EPN/IGS stations: BOGO and JOZE were used. In addition to, a new test station - IGIK was created. In this paper, the results of single frequency GPS observations processing in near real- time are presented. Baselines of 15, 27 and 42 kilometers and sessions of 1, 2, 3, 4, and 6 hours long were processed. While processing we used CODE (Centre for Orbit De- termination in Europe, Bern, Switzerland) predicted products: orbits and ionosphere info. These products are available in real-time and enable near real-time processing. Software Bernese v. 4.2 for Linux and BPE (Bernese Processing Engine) mode were used. These results are shown with a reference to dual frequency weekly solution (the best solution). Obtained GPS positional time and GPS baseline length dependency accuracy is presented for single frequency GPS observations.

  15. Response times across the visual field: empirical observations and application to threshold determination.

    PubMed

    McKendrick, Allison M; Denniss, Jonathan; Turpin, Andrew

    2014-08-01

    This study aimed to determine if response times gathered during perimetry can be exploited within a thresholding algorithm to improve the speed and accuracy of the test. Frequency of seeing (FoS) curves were measured at 24 locations across the central 30° of the visual field of 10 subjects using a Method of Constant Stimuli, with response times recorded for each presentation. Spatial locations were interleaved, and built up over multiple 5-min blocks, in order to mimic the attentional conditions of clinical perimetry. FoS curves were fitted to each participant's data for each location, and response times derived as a function of distance-from-threshold normalised to the slope of each FoS curve. This data was then used to derive a function for the probability of observing response times given the distance-from-threshold, and to seed simulations of a new test procedure (BURTO) that exploited the probability function for stimulus placement. Test time and error were then simulated for patients with various false response rates. When compared with a ZEST algorithm, simulations revealed that BURTO was about one presentation per location faster than ZEST, on average, while sacrificing less precision and bias in threshold estimates than simply terminating the ZEST earlier. Despite response times varying considerably for a given individual and their thresholds, response times can be exploited to reduce the number of presentations required in a visual field test without loss of accuracy. PMID:24802595

  16. The effects of temporal-precision and time-minimization constraints on the spatial and temporal accuracy of aimed hand movements.

    PubMed

    Carlton, L G

    1994-03-01

    Discrete aimed hand movements, made by subjects given temporal-accuracy and time-minimization task instructions, were compared. Movements in the temporal-accuracy task were made to a point target with a goal movement time of 400 ms. A circular target then was manufactured that incorporated the measured spatial errors from the temporal-accuracy task, and subjects attempted to contact the target with a minimum movement time and without missing the circular target (time-minimization task instructions). This procedure resulted in equal movement amplitude and approximately equal spatial accuracy for the two task instructions. Movements under the time-minimization instructions were completed rapidly (M = 307 ms) without target misses, and tended to be made up of two submovements. In contrast, movements under temporal-accuracy instructions were made more slowly (M = 397 ms), matching the goal movement time, and were typically characterized by a single submovement. These data support the hypothesis that movement times, at a fixed movement amplitude versus target width ratio, decrease as the number of submovements increases, and that movements produced under temporal-accuracy and time-minimization have different control characteristics. These control differences are related to the linear and logarithmic speed-accuracy relations observed for temporal-accuracy and time-minimization tasks, respectively. PMID:15757833

  17. Accuracy and optimal timing of activity measurements in estimating the absorbed dose of radioiodine in the treatment of Graves' disease

    NASA Astrophysics Data System (ADS)

    Merrill, S.; Horowitz, J.; Traino, A. C.; Chipkin, S. R.; Hollot, C. V.; Chait, Y.

    2011-02-01

    Calculation of the therapeutic activity of radioiodine 131I for individualized dosimetry in the treatment of Graves' disease requires an accurate estimate of the thyroid absorbed radiation dose based on a tracer activity administration of 131I. Common approaches (Marinelli-Quimby formula, MIRD algorithm) use, respectively, the effective half-life of radioiodine in the thyroid and the time-integrated activity. Many physicians perform one, two, or at most three tracer dose activity measurements at various times and calculate the required therapeutic activity by ad hoc methods. In this paper, we study the accuracy of estimates of four 'target variables': time-integrated activity coefficient, time of maximum activity, maximum activity, and effective half-life in the gland. Clinical data from 41 patients who underwent 131I therapy for Graves' disease at the University Hospital in Pisa, Italy, are used for analysis. The radioiodine kinetics are described using a nonlinear mixed-effects model. The distributions of the target variables in the patient population are characterized. Using minimum root mean squared error as the criterion, optimal 1-, 2-, and 3-point sampling schedules are determined for estimation of the target variables, and probabilistic bounds are given for the errors under the optimal times. An algorithm is developed for computing the optimal 1-, 2-, and 3-point sampling schedules for the target variables. This algorithm is implemented in a freely available software tool. Taking into consideration 131I effective half-life in the thyroid and measurement noise, the optimal 1-point time for time-integrated activity coefficient is a measurement 1 week following the tracer dose. Additional measurements give only a slight improvement in accuracy.

  18. "Right Time, Right Place" Health Communication on Twitter: Value and Accuracy of Location Information

    PubMed Central

    Burton, Scott H; Tanner, Kesler W; West, Joshua H; Barnes, Michael D

    2012-01-01

    Background Twitter provides various types of location data, including exact Global Positioning System (GPS) coordinates, which could be used for infoveillance and infodemiology (ie, the study and monitoring of online health information), health communication, and interventions. Despite its potential, Twitter location information is not well understood or well documented, limiting its public health utility. Objective The objective of this study was to document and describe the various types of location information available in Twitter. The different types of location data that can be ascertained from Twitter users are described. This information is key to informing future research on the availability, usability, and limitations of such location data. Methods Location data was gathered directly from Twitter using its application programming interface (API). The maximum tweets allowed by Twitter were gathered (1% of the total tweets) over 2 separate weeks in October and November 2011. The final dataset consisted of 23.8 million tweets from 9.5 million unique users. Frequencies for each of the location options were calculated to determine the prevalence of the various location data options by region of the world, time zone, and state within the United States. Data from the US Census Bureau were also compiled to determine population proportions in each state, and Pearson correlation coefficients were used to compare each state’s population with the number of Twitter users who enable the GPS location option. Results The GPS location data could be ascertained for 2.02% of tweets and 2.70% of unique users. Using a simple text-matching approach, 17.13% of user profiles in the 4 continental US time zones were able to be used to determine the user’s city and state. Agreement between GPS data and data from the text-matching approach was high (87.69%). Furthermore, there was a significant correlation between the number of Twitter users per state and the 2010 US Census state

  19. Bottom-Up Mechanisms Are Involved in the Relation between Accuracy in Timing Tasks and Intelligence--Further Evidence Using Manipulations of State Motivation

    ERIC Educational Resources Information Center

    Ullen, Fredrik; Soderlund, Therese; Kaaria, Lenita; Madison, Guy

    2012-01-01

    Intelligence correlates with accuracy in various timing tasks. Such correlations could be due to both bottom-up mechanisms, e.g. neural properties that influence both temporal accuracy and cognitive processing, and differences in top-down control. We have investigated the timing-intelligence relation using a simple temporal motor task, isochronous…

  20. Error propagation in relative real-time reverse transcription polymerase chain reaction quantification models: the balance between accuracy and precision.

    PubMed

    Nordgård, Oddmund; Kvaløy, Jan Terje; Farmen, Ragne Kristin; Heikkilä, Reino

    2006-09-15

    Real-time reverse transcription polymerase chain reaction (RT-PCR) has gained wide popularity as a sensitive and reliable technique for mRNA quantification. The development of new mathematical models for such quantifications has generally paid little attention to the aspect of error propagation. In this study we evaluate, both theoretically and experimentally, several recent models for relative real-time RT-PCR quantification of mRNA with respect to random error accumulation. We present error propagation expressions for the most common quantification models and discuss the influence of the various components on the total random error. Normalization against a calibrator sample to improve comparability between different runs is shown to increase the overall random error in our system. On the other hand, normalization against multiple reference genes, introduced to improve accuracy, does not increase error propagation compared to normalization against a single reference gene. Finally, we present evidence that sample-specific amplification efficiencies determined from individual amplification curves primarily increase the random error of real-time RT-PCR quantifications and should be avoided. Our data emphasize that the gain of accuracy associated with new quantification models should be validated against the corresponding loss of precision. PMID:16899212

  1. A Time Projection Chamber for High Accuracy and Precision Fission Cross-Section Measurements

    SciTech Connect

    T. Hill; K. Jewell; M. Heffner; D. Carter; M. Cunningham; V. Riot; J. Ruz; S. Sangiorgio; B. Seilhan; L. Snyder; D. M. Asner; S. Stave; G. Tatishvili; L. Wood; R. G. Baker; J. L. Klay; R. Kudo; S. Barrett; J. King; M. Leonard; W. Loveland; L. Yao; C. Brune; S. Grimes; N. Kornilov; T. N. Massey; J. Bundgaard; D. L. Duke; U. Greife; U. Hager; E. Burgett; J. Deaven; V. Kleinrath; C. McGrath; B. Wendt; N. Hertel; D. Isenhower; N. Pickle; H. Qu; S. Sharma; R. T. Thornton; D. Tovwell; R. S. Towell; S.

    2014-09-01

    The fission Time Projection Chamber (fissionTPC) is a compact (15 cm diameter) two-chamber MICROMEGAS TPC designed to make precision cross-section measurements of neutron-induced fission. The actinide targets are placed on the central cathode and irradiated with a neutron beam that passes axially through the TPC inducing fission in the target. The 4p acceptance for fission fragments and complete charged particle track reconstruction are powerful features of the fissionTPC which will be used to measure fission cross-sections and examine the associated systematic errors. This paper provides a detailed description of the design requirements, the design solutions, and the initial performance of the fissionTPC.

  2. Antenna Modeling and Reconstruction Accuracy of Time Domain-Based Image Reconstruction in Microwave Tomography

    PubMed Central

    Padhi, Shantanu K.; Howard, John

    2013-01-01

    Nonlinear microwave imaging heavily relies on an accurate numerical electromagnetic model of the antenna system. The model is used to simulate scattering data that is compared to its measured counterpart in order to reconstruct the image. In this paper an antenna system immersed in water is used to image different canonical objects in order to investigate the implication of modeling errors on the final reconstruction using a time domain-based iterative inverse reconstruction algorithm and three-dimensional FDTD modeling. With the test objects immersed in a background of air and tap water, respectively, we have studied the impact of antenna modeling errors, errors in the modeling of the background media, and made a comparison with a two-dimensional version of the algorithm. In conclusion even small modeling errors in the antennas can significantly alter the reconstructed image. Since the image reconstruction procedure is highly nonlinear general conclusions are very difficult to make. In our case it means that with the antenna system immersed in water and using our present FDTD-based electromagnetic model the imaging results are improved if refraining from modeling the water-wall-air interface and instead just use a homogeneous background of water in the model. PMID:23606825

  3. Throwing accuracy in the vertical direction during prism adaptation: not simply timing of ball release.

    PubMed

    Martin, T A; Greger, B E; Norris, S A; Thach, W T

    2001-05-01

    In a previous study, others have hypothesized that the variance in vertical errors that occurs while throwing at visual targets is caused by changes in any of three throw parameters: hand location in space, hand translational velocity, and hand orientation. From an analysis of skilled throwers, those authors concluded that vertical error is best correlated with variance in hand orientation, which in turn is related to the timing of ball release. We used a vertical prism adaptation paradigm to investigate which of these throwing parameters subjects use when adapting to external perturbation. Our subjects showed no correlation between hand position or hand translational velocity and ball impact height in normal, over-practiced throwing. However, video-based motion analysis showed that modifications both of position and speed of the hand play an important role when subjects are forced to compensate for a vertically shifting prism perturbation during a dart-like throw (these factors contribute approximately 30% of the adaptation). We concluded that, during adaptation, more degrees of freedom and more sources of potential error are modified to achieve the gaze-throw recalibration required to hit the target than are employed in this type of throw during normal conditions. PMID:11353043

  4. Accuracy of a real-time continuous glucose monitoring system in children with septic shock: A pilot study

    PubMed Central

    Prabhudesai, Sumant; Kanjani, Amruta; Bhagat, Isha; Ravikumar, Karnam G.; Ramachandran, Bala

    2015-01-01

    Aims: The aim of this prospective, observational study was to determine the accuracy of a real-time continuous glucose monitoring system (CGMS) in children with septic shock. Subjects and Methods: Children aged 30 days to 18 years admitted to the Pediatric Intensive Care Unit with septic shock were included. A real-time CGMS sensor was used to obtain interstitial glucose readings. CGMS readings were compared statistically with simultaneous laboratory blood glucose (BG). Results: Nineteen children were included, and 235 pairs of BG-CGMS readings were obtained. BG and CGMS had a correlation coefficient of 0.61 (P < 0.001) and a median relative absolute difference of 17.29%. On Clarke's error grid analysis, 222 (94.5%) readings were in the clinically acceptable zones (A and B). When BG was < 70, 70–180, and > 180 mg/dL, 44%, 100%, and 76.9% readings were in zones A and B, respectively (P < 0.001). The accuracy of CGMS was not affected by the presence of edema, acidosis, vasopressors, steroids, or renal replacement therapy. On receiver operating characteristics curve analysis, a CGMS reading <97 mg/dL predicted hypoglycemia (sensitivity 85.2%, specificity 75%, area under the curve [AUC] =0.85). A reading > 141 mg/dL predicted hyperglycemia (sensitivity 84.6%, specificity 89.6%, AUC = 0.87). Conclusion: CGMS provides a fairly, accurate estimate of BG in children with septic shock. It is unaffected by a variety of clinical variables. The accuracy over extremes of blood sugar may be a concern. We recommend larger studies to evaluate its use for the early detection of hypoglycemia and hyperglycemia. PMID:26730114

  5. Verification of the performance accuracy of a real-time skin-dose tracking system for interventional fluoroscopic procedures

    PubMed Central

    Bednarek, Daniel R.; Barbarits, Jeffery; Rana, Vijay K.; Nagaraja, Srikanta P.; Josan, Madhur S.; Rudin, Stephen

    2011-01-01

    A tracking system has been developed to provide real-time feedback of skin dose and dose rate during interventional fluoroscopic procedures. The dose tracking system (DTS) calculates the radiation dose rate to the patient’s skin using the exposure technique parameters and exposure geometry obtained from the x-ray imaging system digital network (Toshiba Infinix) and presents the cumulative results in a color mapping on a 3D graphic of the patient. We performed a number of tests to verify the accuracy of the dose representation of this system. These tests included comparison of system–calculated dose-rate values with ionization-chamber (6 cc PTW) measured values with change in kVp, beam filter, field size, source-to-skin distance and beam angulation. To simulate a cardiac catheterization procedure, the ionization chamber was also placed at various positions on an Alderson Rando torso phantom and the dose agreement compared for a range of projection angles with the heart at isocenter. To assess the accuracy of the dose distribution representation, Gafchromic film (XR-RV3, ISP) was exposed with the beam at different locations. The DTS and film distributions were compared and excellent visual agreement was obtained within the cm-sized surface elements used for the patient graphic. The dose (rate) values agreed within about 10% for the range of variables tested. Correction factors could be applied to obtain even closer agreement since the variable values are known in real-time. The DTS provides skin-dose values and dose mapping with sufficient accuracy for use in monitoring diagnostic and interventional x-ray procedures. PMID:21731400

  6. Verification of the performance accuracy of a real-time skin-dose tracking system for interventional fluoroscopic procedures

    NASA Astrophysics Data System (ADS)

    Bednarek, Daniel R.; Barbarits, Jeffery; Rana, Vijay K.; Nagaraja, Srikanta P.; Josan, Madhur S.; Rudin, Stephen

    2011-03-01

    A tracking system has been developed to provide real-time feedback of skin dose and dose rate during interventional fluoroscopic procedures. The dose tracking system (DTS) calculates the radiation dose rate to the patient's skin using the exposure technique parameters and exposure geometry obtained from the x-ray imaging system digital network (Toshiba Infinix) and presents the cumulative results in a color mapping on a 3D graphic of the patient. We performed a number of tests to verify the accuracy of the dose representation of this system. These tests included comparison of system-calculated dose-rate values with ionization-chamber (6 cc PTW) measured values with change in kVp, beam filter, field size, source-to-skin distance and beam angulation. To simulate a cardiac catheterization procedure, the ionization chamber was also placed at various positions on an Alderson Rando torso phantom and the dose agreement compared for a range of projection angles with the heart at isocenter. To assess the accuracy of the dose distribution representation, Gafchromic film (XR-RV3, ISP) was exposed with the beam at different locations. The DTS and film distributions were compared and excellent visual agreement was obtained within the cm-sized surface elements used for the patient graphic. The dose (rate) values agreed within about 10% for the range of variables tested. Correction factors could be applied to obtain even closer agreement since the variable values are known in real-time. The DTS provides skin-dose values and dose mapping with sufficient accuracy for use in monitoring diagnostic and interventional x-ray procedures.

  7. Verification of the performance accuracy of a real-time skin-dose tracking system for interventional fluoroscopic procedures.

    PubMed

    Bednarek, Daniel R; Barbarits, Jeffery; Rana, Vijay K; Nagaraja, Srikanta P; Josan, Madhur S; Rudin, Stephen

    2011-02-13

    A tracking system has been developed to provide real-time feedback of skin dose and dose rate during interventional fluoroscopic procedures. The dose tracking system (DTS) calculates the radiation dose rate to the patient's skin using the exposure technique parameters and exposure geometry obtained from the x-ray imaging system digital network (Toshiba Infinix) and presents the cumulative results in a color mapping on a 3D graphic of the patient. We performed a number of tests to verify the accuracy of the dose representation of this system. These tests included comparison of system-calculated dose-rate values with ionization-chamber (6 cc PTW) measured values with change in kVp, beam filter, field size, source-to-skin distance and beam angulation. To simulate a cardiac catheterization procedure, the ionization chamber was also placed at various positions on an Alderson Rando torso phantom and the dose agreement compared for a range of projection angles with the heart at isocenter. To assess the accuracy of the dose distribution representation, Gafchromic film (XR-RV3, ISP) was exposed with the beam at different locations. The DTS and film distributions were compared and excellent visual agreement was obtained within the cm-sized surface elements used for the patient graphic. The dose (rate) values agreed within about 10% for the range of variables tested. Correction factors could be applied to obtain even closer agreement since the variable values are known in real-time. The DTS provides skin-dose values and dose mapping with sufficient accuracy for use in monitoring diagnostic and interventional x-ray procedures. PMID:21731400

  8. Respiratory rate: measurement of variability over time and accuracy at different counting periods.

    PubMed Central

    Simoes, E A; Roark, R; Berman, S; Esler, L L; Murphy, J

    1991-01-01

    The respiratory rates/minute of 97 children were monitored every 10-15 minutes over one hour, by an observer and by pneumogram, at which times two 30 second and one 60 second counts were obtained. The children were under 5 years of age with lower respiratory tract infections (n = 20), upper respiratory tract infections (n = 34), or controls without acute respiratory infection (n = 43). The difference between respiratory rate count determined simultaneously by observation and pneumogram in relation to their mean count was analysed for the 60 second counting period, 30 plus 30 second period, and the 30 second period doubled. The mean difference for the 60 second period was 1.79, for the 30 plus 30 second period 1.42, and for the 30 second period doubled 1.72. The variability between respiratory rate counts determined by observation and pneumogram was significantly lower in counts obtained when the subject was sleeping and higher when agitated compared with obtaining a count when the subject was awake and calm or feeding. The variability was also significantly lower in subjects with lower respiratory tract infections compared with those with upper respiratory tract infections and control subjects without respiratory symptoms. In the same patient, over the one hour, 50% of the 60 second counts varied by up to 14 breaths/minute and 75% by up to 21 breaths/minute. The least variability was seen in children with a lower respiratory tract infection, who tended to maintain their rapid breathing in contrast to those with an upper respiratory tract infection and controls without respiratory symptoms. About 10% of initial 30 second counts, 12% of 60 second, and 16% of initial and repeat 30 second attempts to obtain accurate counts failed. Failures occurred more frequently in children <2 months of age and those agitated. The data from this study suggest that one minute's counting either at a stretch or in two blocks of 30 second intervals is better than counting the respiratory

  9. Impact of time-variable vegetation on accuracy of rapid hydrologic predictions

    NASA Astrophysics Data System (ADS)

    Stec, Magdalena; Niedzielski, Tomasz

    2016-04-01

    It is crucial to identify the processes that impact errors of hydrologic forecasts. Since existence of vegetation and its ability to store precipitation is an important element of water distribution in the catchment, especially at the beginning of a rainfall event, it may be considered as one of the processes influencing skills of hydrological forecasts. The main objective of the study is to verify the hypothesis that water level predictions are controlled by vegetation dynamics in the contributing mountainous basins. The analysis is conducted for the upper Nysa Klodzka catchment with the outlet in Bardo (SW Poland). The basin includes a mid-mountain abasement covered with crops, while surrounding medium-altitude mountain ranges are mainly covered with forests. We focus on the entire year, from autumn 2013 to summer 2014. Herein, we analyze prediction errors and efficiency measures of hydrologic forecasts provided by two stochastic models - uni- and multivariate autoregressive models as well as their two-model ensemble prediction. In addition, we use the satellite-derived Leaf Area Index (LAI) images from the Moderate Resolution Imaging Spectroradiometer (MODIS). Hydrological prognoses are derived by the HydroProg real-time rapid forecasting system, built at the University of Wroclaw (Poland) in frame of the research project 2011/01/D/ST10/04171 of the National Science Centre of Poland. Correlation analysis between the plant maximum water storage capacity and prediction error/skill statistics (mean absolute error, root mean square error, Nash-Sutcliffe efficiency , index of agreement) is conducted. To cope with small sample size, the bootstrap simulation is performed. We conclude that there is a strong negative association between mean or median prediction errors and vegetation state for all meteorological seasons of a year. This result implies that basins with higher interception potential are more vulnerable to forecast inaccuracy than those with sparse natural

  10. 28 CFR 20.37 - Responsibility for accuracy, completeness, currency, and integrity.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., currency, and integrity. 20.37 Section 20.37 Judicial Administration DEPARTMENT OF JUSTICE CRIMINAL JUSTICE INFORMATION SYSTEMS Federal Systems and Exchange of Criminal History Record Information § 20.37 Responsibility... justice agency contributing data to the III System and the FIRS to assure that information on...

  11. 28 CFR 20.37 - Responsibility for accuracy, completeness, currency, and integrity.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., currency, and integrity. 20.37 Section 20.37 Judicial Administration DEPARTMENT OF JUSTICE CRIMINAL JUSTICE INFORMATION SYSTEMS Federal Systems and Exchange of Criminal History Record Information § 20.37 Responsibility... justice agency contributing data to the III System and the FIRS to assure that information on...

  12. 28 CFR 20.37 - Responsibility for accuracy, completeness, currency, and integrity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., currency, and integrity. 20.37 Section 20.37 Judicial Administration DEPARTMENT OF JUSTICE CRIMINAL JUSTICE INFORMATION SYSTEMS Federal Systems and Exchange of Criminal History Record Information § 20.37 Responsibility... justice agency contributing data to the III System and the FIRS to assure that information on...

  13. 28 CFR 20.37 - Responsibility for accuracy, completeness, currency, and integrity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., currency, and integrity. 20.37 Section 20.37 Judicial Administration DEPARTMENT OF JUSTICE CRIMINAL JUSTICE INFORMATION SYSTEMS Federal Systems and Exchange of Criminal History Record Information § 20.37 Responsibility... justice agency contributing data to the III System and the FIRS to assure that information on...

  14. 28 CFR 20.37 - Responsibility for accuracy, completeness, currency, and integrity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., currency, and integrity. 20.37 Section 20.37 Judicial Administration DEPARTMENT OF JUSTICE CRIMINAL JUSTICE INFORMATION SYSTEMS Federal Systems and Exchange of Criminal History Record Information § 20.37 Responsibility... justice agency contributing data to the III System and the FIRS to assure that information on...

  15. 40 CFR 1066.245 - Response time verification.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... dynamometer's automated process to verify response time. Perform this test at two different inertia settings... observed settling response time must be less than 100 milliseconds for each inertia setting. ER15SE11.085...

  16. 40 CFR 1066.245 - Response time verification.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... dynamometer's automated process to verify response time. Perform this test at two different inertia settings... observed settling response time must be less than 100 milliseconds for each inertia setting. ER15SE11.085...

  17. A reminder on millisecond timing accuracy and potential replication failure in computer-based psychology experiments: An open letter.

    PubMed

    Plant, Richard R

    2016-03-01

    There is an ongoing 'replication crisis' across the field of psychology in which researchers, funders, and members of the public are questioning the results of some scientific studies and the validity of the data they are based upon. However, few have considered that a growing proportion of research in modern psychology is conducted using a computer. Could it simply be that the hardware and software, or experiment generator, being used to run the experiment itself be a cause of millisecond timing error and subsequent replication failure? This article serves as a reminder that millisecond timing accuracy in psychology studies remains an important issue and that care needs to be taken to ensure that studies can be replicated on current computer hardware and software. PMID:25761394

  18. Analyzing Response Times in Tests with Rank Correlation Approaches

    ERIC Educational Resources Information Center

    Ranger, Jochen; Kuhn, Jorg-Tobias

    2013-01-01

    It is common practice to log-transform response times before analyzing them with standard factor analytical methods. However, sometimes the log-transformation is not capable of linearizing the relation between the response times and the latent traits. Therefore, a more general approach to response time analysis is proposed in the current…

  19. Study of the response time of MR dampers

    NASA Astrophysics Data System (ADS)

    Guan, Xinchun; Guo, Pengfei; Ou, Jinping

    2009-07-01

    Response time is an important parameter which determines the applied fields and practical vibration reduction effects of magnetorheological (MR) dampers. However, up to now, only a few papers discuss the test and analysis of response times. In this paper, the response time of a large-scale MR damper at different velocities and currents was firstly tested. Then, the transient magnetic field excited by the time-variant excitation current was simulated by finite element method (FEM). Based on the variation of the shear yield stress of magnetorheological fluids in the gap between the cylinder and the piston, the response time of the MR damper was investigated. Influences of eddy current and excitation current response time on the damper's response were also explored. Results show that by utilizing finite elements method, the calculated average effective shear yield strength can be used to predict the response time of a MR damper. Electromagnetic response is the predominant factor influencing the response time of a MR damper, and reducing eddy currents is the key to accelerate the response of a MR damper. Moreover, influence of eddy currents is much larger under stepping down excitation currents than stepping up currents, and with a same magnitude of step, no matter when the current increases or decreases, the smaller the initial current, the greater the eddy current affects a damper's response and the longer the response time of damping force is. A fast response excitation current may induce large eddy currents which reduce the response of the damper instead.

  20. System measures response time of photomultiplier tubes

    NASA Technical Reports Server (NTRS)

    Lauver, M. R.

    1968-01-01

    Calibration system enables precise determination of rise time of photosensitive detectors. To perform a calibration, the time-voltage curve of the excitation voltage for a light source is compared with the time-voltage curve of the voltage output from a photosensitive detector which is responding to the light.

  1. Accuracy of pleth variability index to predict fluid responsiveness in mechanically ventilated patients: a systematic review and meta-analysis.

    PubMed

    Chu, Haitao; Wang, Yong; Sun, Yanfei; Wang, Gang

    2016-06-01

    To systemically evaluate the accuracy of pleth variability index to predict fluid responsiveness in mechanically ventilated patients. A literature search of PUBMED, OVID, CBM, CNKI and Wanfang Data for clinical studies in which the accuracy of pleth variability index to predict fluid responsiveness was performed (last update 5 April 2015). Related journals were also searched manually. Two reviewers independently assessed trial quality according to the modified QUADAS items. Heterogeneous studies and meta-analysis were conducted by Meta-Disc 1.4 software. A subgroup analysis in the operating room (OR) and in intensive care unit (ICU) was also performed. Differences between subgroups were analyzed using the interaction test. A total of 18 studies involving 665 subjects were included. The pooled area under the receiver operating characteristic curve (AUC) to predict fluid responsiveness in mechanically ventilated patients was 0.88 [95 % confidence interval (CI) 0.84-0.91]. The pooled sensitivity and specificity were 0.73 (95 % CI 0.68-0.78) and 0.82 (95 % CI 0.77-0.86), respectively. No heterogeneity was found within studies nor between studies. And there was no significant heterogeneity within each subgroup. No statistical differences were found between OR subgroup and ICU subgroup in the AUC [0.89 (95 % CI 0.85-0.92) versus 0.90 (95 % CI 0.82-0.94); P = 0.97], and in the specificity [0.84 (95 % CI 0.75-0.86) vs. 0.84 (95 % CI 0.75-0.91); P = 1.00]. Sensitivity was higher in the OR subgroup than the ICU subgroup [0.84 (95 % CI 0.78-0.88) vs. 0.56 (95 % CI 0.47-0.64); P = 0.00004]. The pleth variability index has a reasonable ability to predict fluid responsiveness. PMID:26242233

  2. High-Accuracy Measurement of the Differential Scalar Polarizability of a Sr+88 Clock Using the Time-Dilation Effect

    NASA Astrophysics Data System (ADS)

    Dubé, Pierre; Madej, Alan A.; Tibbo, Maria; Bernard, John E.

    2014-05-01

    We report a high-accuracy measurement of the differential static scalar polarizability Δα0 of the 5sS1/22-4dD5/22 transition of the Sr+88 ion. The high accuracy is obtained by comparing the micromotion-induced positive scalar Stark shift to the negative time-dilation shift. Measurement of the trap drive frequency where these shifts cancel is used to determine Δα0 without the need to determine the electric field. Δα0 is a critical parameter for the operation of frequency standards as it determines the blackbody radiation frequency shift coefficient, the largest source of uncertainty in the Sr+88 ion clock. The measured value of Δα0 is -4.7938(71)×10-40 J m2/V2. Taking into account the dynamic correction, the blackbody shift at 300 K is 0.247 99(37) Hz. The contribution of the blackbody shift coefficient to the uncertainty of the ion standard has been reduced by a factor of 24, from 2×10-17 to 8.3×10-19. The revised total uncertainty of our reference standard is 1.2×10-17, limited by the blackbody field evaluation. An additional benefit of the low uncertainty of Δα0 is the ability to suppress, by a factor of about 200, the net micromotion frequency shifts.

  3. High-accuracy measurement of the differential scalar polarizability of a 88Sr+ clock using the time-dilation effect.

    PubMed

    Dubé, Pierre; Madej, Alan A; Tibbo, Maria; Bernard, John E

    2014-05-01

    We report a high-accuracy measurement of the differential static scalar polarizability Δα(0) of the 5s(2)S(1/2)-4d(2)D(5/2) transition of the (88)Sr(+) ion. The high accuracy is obtained by comparing the micromotion-induced positive scalar Stark shift to the negative time-dilation shift. Measurement of the trap drive frequency where these shifts cancel is used to determine Δα(0) without the need to determine the electric field. Δα(0) is a critical parameter for the operation of frequency standards as it determines the blackbody radiation frequency shift coefficient, the largest source of uncertainty in the (88)Sr(+) ion clock. The measured value of Δα(0) is -4.7938(71) × 10(-40) J m(2)/V(2). Taking into account the dynamic correction, the blackbody shift at 300 K is 0.247,99(37) Hz. The contribution of the blackbody shift coefficient to the uncertainty of the ion standard has been reduced by a factor of 24, from 2 × 10(-17) to 8.3 × 10(-19). The revised total uncertainty of our reference standard is 1.2 × 10(-17), limited by the blackbody field evaluation. An additional benefit of the low uncertainty of Δα(0) is the ability to suppress, by a factor of about 200, the net micromotion frequency shifts. PMID:24836242

  4. Diagnostic Accuracy of Real-Time Shear Wave Elastography for Staging of Liver Fibrosis: A Meta-Analysis.

    PubMed

    Li, Changtian; Zhang, Changsheng; Li, Junlai; Huo, Huiping; Song, Danfei

    2016-01-01

    BACKGROUND The present meta-analysis, based on previous studies, was aimed to evaluate the test accuracy of real-time shear wave elastography (SWE) for the staging of liver fibrosis. MATERIAL AND METHODS A systematic search on MEDLINE, PubMed, Embase, and Google Scholar databases was conducted, and data on SWE tests and liver fibrosis staging were collected. For each cut-off stage of fibrosis (F≥2, F≥3, and F≥4), pooled results of sensitivity, specificity, and area under summary receiver operating characteristic (SROC) curve were analyzed. The study heterogeneity was evaluated by χ2 and I2 tests. I2>50% or P≤0.05 indicates there was heterogeneity, and then a random-effects model was applied. Otherwise, the fixed-effects model was used. The publication bias was evaluated using Deeks funnel plots asymmetry test and Fagan plot analysis was performed. RESULTS Finally, 934 patients from 8 published studies were included in the analysis. The pooled sensitivity and specificity of SWE for F≥2 were 85.0% (95% CI, 82-88%) and 81% (95% CI, 71-88%), respectively. The area under the SROC curve with 95% CI was presented as 0.88 (95% CI, 85-91%). The pooled sensitivity and specificity of SWE for F≥3 were 90.0% (95% CI, 83.0-95.0%) and 81.0% (95% CI, 75.0-86.0%), respectively, corresponding to an area of SROC of 0.94 (95% CI, 92-96%). The pooled sensitivity and specificity of SWE for F≥4 were 87.0% (95% CI, 80.0-92.0%) and 88.0% (95% CI, 80.0-93.0%), respectively, corresponding to an area of SROC of 0.92 (95% CI, 89-94%). CONCLUSIONS The overall accuracy of SWE is high and clinically useful for the staging of liver fibrosis. Compared to the results of meta-analyses on other tests, such as RTE, TE, and ARFI, the performance of SWE is nearly identical in accuracy for the evaluation of cirrhosis. For the evaluation of significant liver fibrosis (F≥2), the overall accuracy of SWE seems to be similar to ARFI, but more accurate than RTE and TE. PMID:27102449

  5. Diagnostic Accuracy of Real-Time Shear Wave Elastography for Staging of Liver Fibrosis: A Meta-Analysis

    PubMed Central

    Li, Changtian; Zhang, Changsheng; Li, Junlai; Huo, Huiping; Song, Danfei

    2016-01-01

    Background The present meta-analysis, based on previous studies, was aimed to evaluate the test accuracy of real-time shear wave elastography (SWE) for the staging of liver fibrosis. Material/Methods A systematic search on MEDLINE, PubMed, Embase, and Google Scholar databases was conducted, and data on SWE tests and liver fibrosis staging were collected. For each cut-off stage of fibrosis (F≥2, F≥3, and F≥4), pooled results of sensitivity, specificity, and area under summary receiver operating characteristic (SROC) curve were analyzed. The study heterogeneity was evaluated by χ2 and I2 tests. I2>50% or P≤0.05 indicates there was heterogeneity, and then a random-effects model was applied. Otherwise, the fixed-effects model was used. The publication bias was evaluated using Deeks funnel plots asymmetry test and Fagan plot analysis was performed. Results Finally, 934 patients from 8 published studies were included in the analysis. The pooled sensitivity and specificity of SWE for F≥2 were 85.0% (95% CI, 82–88%) and 81% (95% CI, 71–88%), respectively. The area under the SROC curve with 95% CI was presented as 0.88 (95% CI, 85–91%). The pooled sensitivity and specificity of SWE for F≥3 were 90.0% (95% CI, 83.0–95.0%) and 81.0% (95% CI, 75.0–86.0%), respectively, corresponding to an area of SROC of 0.94 (95% CI, 92–96%). The pooled sensitivity and specificity of SWE for F≥4 were 87.0% (95% CI, 80.0–92.0%) and 88.0% (95% CI, 80.0–93.0%), respectively, corresponding to an area of SROC of 0.92 (95% CI, 89–94%). Conclusions The overall accuracy of SWE is high and clinically useful for the staging of liver fibrosis. Compared to the results of meta-analyses on other tests, such as RTE, TE, and ARFI, the performance of SWE is nearly identical in accuracy for the evaluation of cirrhosis. For the evaluation of significant liver fibrosis (F≥2), the overall accuracy of SWE seems to be similar to ARFI, but more accurate than RTE and TE. PMID

  6. Design of responsive polymer surfaces with ultrafast response time

    NASA Astrophysics Data System (ADS)

    Genzer, Jan; Ozcam, Evren; Willoughby, Julie

    2009-03-01

    Responsive surfaces with tailorable surface-reconstruction kinetics and switching hysteresis were prepared from poly(vinylmethylsiloxane) (PVMS) networks modified with thiol alkanes to provide hydrophobic or hydrophilic surface properties. The cooperative effects of polymer mobility, arising from the high flexibility of the siloxane backbone, and the enthalpic interactions between the contacting medium and the PVMS functionalized surface control the degree of responsiveness. Exposing the modified-elastomer surfaces to water resulted in rearrangement of the hydrophilic alkanes at the surface. The kinetics of reconstruction and reversibility were established by measuring the surface wettability via dynamic contact angle. By controlling the formation of semi-crystalline regions in our substrates we demonstrate either ``sluggish'' kinetics and eventual surface ``freezing'' and stability or stimuli-responsive substrates with a magnitude of change and repeated reversibility unparallel to most polymeric surfaces.

  7. Dispersion of Response Times Reveals Cognitive Dynamics

    ERIC Educational Resources Information Center

    Holden, John G.; Van Orden, Guy C.; Turvey, Michael T.

    2009-01-01

    Trial-to-trial variation in word-pronunciation times exhibits 1/f scaling. One explanation is that human performances are consequent on multiplicative interactions among interdependent processes-interaction dominant dynamics. This article describes simulated distributions of pronunciation times in a further test for multiplicative interactions and…

  8. Accuracy of sign interpreting and real-time captioning of science videos for the delivery of instruction to deaf students

    NASA Astrophysics Data System (ADS)

    Sadler, Karen L.

    2009-04-01

    The purpose of this study was to quantitatively examine the impact of third-party support service providers on the quality of science information available to deaf students in regular science classrooms. Three different videotapes that were developed by NASA for high school science classrooms were selected for the study, allowing for different concepts and vocabulary to be examined. The focus was on the accuracy of translation as measured by the number of key science words included in the transcripts (captions) or videos (interpreted). Data were collected via transcripts completed by CART (computer assisted real-time captionists) or through videos of sign language interpreters. All participants were required to listen to and translate these NASA educational videos with no prior experience with this information so as not to influence their delivery. CART personnel using captions were found to be significantly more accurate in the delivery of science words as compared to the sign language interpreters in this study.

  9. Dispersion of Response Times Reveals Cognitive Dynamics

    PubMed Central

    Holden, John G.; Van Orden, Guy C.; Turvey, Michael T.

    2013-01-01

    Trial to trial variation in word pronunciation times exhibits 1/f scaling. One explanation is that human performances are consequent on multiplicative interactions among interdependent processes – interaction dominant dynamics. This article describes simulated distributions of pronunciation times in a further test for multiplicative interactions and interdependence. Individual participant distributions of ≈1100 word pronunciation times are successfully mimicked for each participant in combinations of lognormal and power law behavior. Successful hazard function simulations generalize these results to establish interaction dominant dynamics, in contrast with component dominant dynamics, as a likely mechanism for cognitive activity. PMID:19348544

  10. Modeling an Application's Theoretical Minimum and Average Transactional Response Times

    SciTech Connect

    Paiz, Mary Rose

    2015-04-01

    The theoretical minimum transactional response time of an application serves as a ba- sis for the expected response time. The lower threshold for the minimum response time represents the minimum amount of time that the application should take to complete a transaction. Knowing the lower threshold is beneficial in detecting anomalies that are re- sults of unsuccessful transactions. On the converse, when an application's response time falls above an upper threshold, there is likely an anomaly in the application that is causing unusual performance issues in the transaction. This report explains how the non-stationary Generalized Extreme Value distribution is used to estimate the lower threshold of an ap- plication's daily minimum transactional response time. It also explains how the seasonal Autoregressive Integrated Moving Average time series model is used to estimate the upper threshold for an application's average transactional response time.

  11. A double dissociation between accuracy and time of execution on attentional tasks in Alzheimer's disease and multi-infarct dementia.

    PubMed

    Gainotti, G; Marra, C; Villa, G

    2001-04-01

    Two cancellation/attentional tasks: (i) Lines Cancellation (LC) and Multiple Features Targets Cancellation (MFTC) and (ii) a standard battery of neuropsychological tests, the Mental Deterioration Battery (MDB), were administered to 68 patients with dementia of the Alzheimer's type (DAT) and 40 patients with multi-infarct dementia (MID), who were accurately matched for the overall severity of dementia, and to 40 normal controls. Both accuracy and time of execution were considered in evaluating performance on the two cancellation tasks, which involved visuospatial exploration and psychomotor speed, but were differently demanding in terms of selective attention. On the first cancellation task (LC), requiring a lower attentional load, the two demented patient groups performed at the same level of accuracy. On the second cancellation task (MFTC), which was more demanding in terms of selective and divided attention, DAT patients were significantly less accurate than MID patients, making a higher number of 'false-alarm' errors. Conversely, the time employed in the execution of both LC and MFTC took longer for MID than for DAT patients, suggesting a greater impairment of psychomotor speed in MID. In the MDB, DAT patients scored significantly worse than MID patients on several measures of episodic memory (the immediate recall, delayed recall and delayed recognition of Rey's Auditory Verbal Learning Test) and on a test of visual-spatial memory. These data suggest that, while psychomotor speed and the lower (sensorimotor) levels of attention are preferentially impaired in subcortical forms of dementia such as MID, the higher levels of selective and divided attention are more markedly disrupted in the Alzheimer type of dementia. PMID:11287373

  12. A method to improve the stability and accuracy of ANN- and SVM-based time series models for long-term groundwater level predictions

    NASA Astrophysics Data System (ADS)

    Yoon, Heesung; Hyun, Yunjung; Ha, Kyoochul; Lee, Kang-Kun; Kim, Gyoo-Bum

    2016-05-01

    The prediction of long-term groundwater level fluctuations is necessary to effectively manage groundwater resources and to assess the effects of changes in rainfall patterns on groundwater resources. In the present study, a weighted error function approach was utilised to improve the performance of artificial neural network (ANN)- and support vector machine (SVM)-based recursive prediction models for the long-term prediction of groundwater levels in response to rainfall. The developed time series models were applied to groundwater level data from 5 groundwater-monitoring stations in South Korea. The results demonstrated that the weighted error function approach can improve the stability and accuracy of recursive prediction models, especially for ANN models. The comparison of the model performance showed that the recursive prediction performance of the SVM was superior to the performance of the ANN in this case study.

  13. Response modalities and time-sharing performance

    NASA Technical Reports Server (NTRS)

    Vidulich, Michael A.

    1986-01-01

    An experiment performed to investigate the role of resource competition and asymmetric transfer in dual-task performance is described. It is shown that there is an advantage to mixed manual/speech response modality configurations that cannot be accounted for by asymmetric transfer. The present results support the multiple resources approach to the application of speech technology. Once speech recognition achieves an acceptable level of operational reliability, speech controls can be used to reduce resource competition and improve performance in multitask environments.

  14. Temperate grass response to timing of grazing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grazing management has a significant impact on pasture growth. We determined how timing of grazing influences grass productivity, yield distribution, and persistence. Meadow fescue [Schedonorus pratensis (Huds.) P. Beauv.], orchardgrass (Dactylis glomerata L.), quackgrass [Elymus repens (L.) Gould...

  15. A Study of Bayesian Estimation and Comparison of Response Time Models in Item Response Theory

    ERIC Educational Resources Information Center

    Suh, Hongwook

    2010-01-01

    Response time has been regarded as an important source for investigating the relationship between human performance and response speed. It is important to examine the relationship between response time and item characteristics, especially in the perspective of the relationship between response time and various factors that affect examinee's…

  16. OSLD energy response performance and dose accuracy at 24 - 1250 keV: Comparison with TLD-100H and TLD-100

    SciTech Connect

    Kadir, A. B. A.; Priharti, W.; Samat, S. B.; Dolah, M. T.

    2013-11-27

    OSLD was evaluated in terms of energy response and accuracy of the measured dose in comparison with TLD-100H and TLD-100. The OSLD showed a better energy response performance for H{sub p}(10) whereas for H{sub p}(0.07), TLD-100H is superior than the others. The OSLD dose accuracy is comparable with the other two dosimeters since it fulfilled the requirement of the ICRP trumpet graph analysis.

  17. Using Response Times for Item Selection in Adaptive Testing

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    2008-01-01

    Response times on items can be used to improve item selection in adaptive testing provided that a probabilistic model for their distribution is available. In this research, the author used a hierarchical modeling framework with separate first-level models for the responses and response times and a second-level model for the distribution of the…

  18. A Lognormal Model for Response Times on Test Items

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    2006-01-01

    A lognormal model for the response times of a person on a set of test items is investigated. The model has a parameter structure analogous to the two-parameter logistic response models in item response theory, with a parameter for the speed of each person as well as parameters for the time intensity and discriminating power of each item. It is…

  19. Real-time continuous glucose monitoring shows high accuracy within 6 hours after sensor calibration: a prospective study.

    PubMed

    Yue, Xiao-Yan; Zheng, Yi; Cai, Ye-Hua; Yin, Ning-Ning; Zhou, Jian-Xin

    2013-01-01

    Accurate and timely glucose monitoring is essential in intensive care units. Real-time continuous glucose monitoring system (CGMS) has been advocated for many years to improve glycemic management in critically ill patients. In order to determine the effect of calibration time on the accuracy of CGMS, real-time subcutaneous CGMS was used in 18 critically ill patients. CGMS sensor was calibrated with blood glucose measurements by blood gas/glucose analyzer every 12 hours. Venous blood was sampled every 2 to 4 hours, and glucose concentration was measured by standard central laboratory device (CLD) and by blood gas/glucose analyzer. With CLD measurement as reference, relative absolute difference (mean±SD) in CGMS and blood gas/glucose analyzer were 14.4%±12.2% and 6.5%±6.2%, respectively. The percentage of matched points in Clarke error grid zone A was 74.8% in CGMS, and 98.4% in blood gas/glucose analyzer. The relative absolute difference of CGMS obtained within 6 hours after sensor calibration (8.8%±7.2%) was significantly less than that between 6 to 12 hours after calibration (20.1%±13.5%, p<0.0001). The percentage of matched points in Clarke error grid zone A was also significantly higher in data sets within 6 hours after calibration (92.4% versus 57.1%, p<0.0001). In conclusion, real-time subcutaneous CGMS is accurate in glucose monitoring in critically ill patients. CGMS sensor should be calibrated less than 6 hours, no matter what time interval recommended by manufacturer. PMID:23555886

  20. Using Lunar Observations to Validate Pointing Accuracy and Geolocation, Detector Sensitivity Stability and Static Point Response of the CERES Instruments

    NASA Technical Reports Server (NTRS)

    Daniels, Janet L.; Smith, G. Louis; Priestley, Kory J.; Thomas, Susan

    2014-01-01

    Validation of in-orbit instrument performance is a function of stability in both instrument and calibration source. This paper describes a method using lunar observations scanning near full moon by the Clouds and Earth Radiant Energy System (CERES) instruments. The Moon offers an external source whose signal variance is predictable and non-degrading. From 2006 to present, these in-orbit observations have become standardized and compiled for the Flight Models -1 and -2 aboard the Terra satellite, for Flight Models-3 and -4 aboard the Aqua satellite, and beginning 2012, for Flight Model-5 aboard Suomi-NPP. Instrument performance measurements studied are detector sensitivity stability, pointing accuracy and static detector point response function. This validation method also shows trends per CERES data channel of 0.8% per decade or less for Flight Models 1-4. Using instrument gimbal data and computed lunar position, the pointing error of each detector telescope, the accuracy and consistency of the alignment between the detectors can be determined. The maximum pointing error was 0.2 Deg. in azimuth and 0.17 Deg. in elevation which corresponds to an error in geolocation near nadir of 2.09 km. With the exception of one detector, all instruments were found to have consistent detector alignment from 2006 to present. All alignment error was within 0.1o with most detector telescopes showing a consistent alignment offset of less than 0.02 Deg.

  1. Using lunar observations to validate pointing accuracy and geolocation, detector sensitivity stability and static point response of the CERES instruments

    NASA Astrophysics Data System (ADS)

    Daniels, Janet; Smith, G. Louis; Priestley, Kory J.; Thomas, Susan

    2014-10-01

    Validation of in-orbit instrument performance is a function of stability in both instrument and calibration source. This paper describes a method using lunar observations scanning near full moon by the Clouds and Earth Radiant Energy System (CERES) instruments. The Moon offers an external source whose signal variance is predictable and non-degrading. From 2006 to present, these in-orbit observations have become standardized and compiled for the Flight Models -1 and -2 aboard the Terra satellite, for Flight Models-3 and -4 aboard the Aqua satellite, and beginning 2012, for Flight Model-5 aboard Suomi-NPP. Instrument performance measurements studied are detector sensitivity stability, pointing accuracy and static detector point response function. This validation method also shows trends per CERES data channel of 0.8% per decade or less for Flight Models 1-4. Using instrument gimbal data and computed lunar position, the pointing error of each detector telescope, the accuracy and consistency of the alignment between the detectors can be determined. The maximum pointing error was 0.2o in azimuth and 0.17o in elevation which corresponds to an error in geolocation near nadir of 2.09 km. With the exception of one detector, all instruments were found to have consistent detector alignment from 2006 to present. All alignment error was within 0.1o with most detector telescopes showing a consistent alignment offset of less than 0.02o.

  2. Acute response in vivo of a fiber-optic sensor for continuous glucose monitoring from canine studies on point accuracy.

    PubMed

    Liao, Kuo-Chih; Chang, Shih-Chieh; Chiu, Cheng-Yang; Chou, Yu-Hsiang

    2010-01-01

    The objective of this study was to evaluate the acute response of Sencil(™), a fiber-optic sensor, in point accuracy for glucose monitoring in vivo on healthy dogs under anesthesia. A total of four dogs with clinically normal glycemia were implanted with one sensor each in the chest region to measure the interstitial glucose concentration during the ovariohysterectomy procedure. The data was acquired every 10 seconds after initiation, and was compared to the concentration of venous plasma glucose sampled during the surgery procedures for accuracy of agreement analysis. In the four trials with a range of 71-297 mg/dL plasma glucose, the collected 21 pairs of ISF readings from the Sencil™ and the plasma reference showed superior dispersion of residue values than the conventional system, and a linear correlation (the Pearson correlation coefficient is 0.9288 and the y-intercept is 14.22 mg/dL). The MAD (17.6 mg/dL) and RMAD (16.16%) of Sencil™ measurements were in the comparable range of the conventional system. The Clarke error grid analysis indicated that 100% of the paired points were in the clinically acceptable zone A (61.9%) and B (38.1%). PMID:22163627

  3. Effect of storage time and framework design on the accuracy of maxillary cobalt-chromium cast removable partial dentures

    PubMed Central

    Viswambaran, M.; Sundaram, R. K.

    2015-01-01

    Statement of Problem: Inaccuracies in the fit of palatal major connectors may be related to distortion of the wax pattern due to prolonged storage time and faulty major connector design. Purpose: This in vitro study was carried out to find out the effect of storage time and major connector design on the accuracy of cobalt-chromium cast removable partial dentures (RPDs). Materials and Methods: A brass metal die with a Kennedy Class III, modification 1, the partially edentulous arch was used as a master die. Thirty-six refractory casts were fabricated from the master die. The refractory casts were divided into three groups (Group I: Anterior-posterior palatal bar, Group II: Palatal strap and Group III: Palatal plate) based on the design of maxillary major connector and subdivided into four groups (sub Group A: 01 h, sub Group B: 03 h, Sub Group C: 06 h, and sub Group D: 24 h) based on the storage time. For each group, 12 frameworks were fabricated. The influence of wax pattern storage time and the accuracy of the fit palatal major connector designs on the master die were compared. Casting defects (nodules/incompleteness) of the frameworks were also evaluated before finishing and polishing. Repeated measures analysis of variance was used to analyze the data. Results: The gap discrepancy was least in sub Group A (01 h) followed by sub Group B (03 h) and C (06 h) and most in sub Group D (24 h). Statistically significant differences (P < 0.05 in all locations L1–L5) in the fit of the framework were related to the design of the major connector. The gap discrepancy was least in Group I (anterior-posterior palatal bar) followed by Group II (palatal strap) and most in Group II (palatal plate). Conclusions: It is recommended that the wax patterns for RPD to be invested immediately on completion of the wax procedure. The selection of a major connector design is crucial for an accurate fit of RPD. PMID:26681850

  4. Accuracy and reliability of multi-GNSS real-time precise positioning: GPS, GLONASS, BeiDou, and Galileo

    NASA Astrophysics Data System (ADS)

    Li, Xingxing; Ge, Maorong; Dai, Xiaolei; Ren, Xiaodong; Fritsche, Mathias; Wickert, Jens; Schuh, Harald

    2015-06-01

    In this contribution, we present a GPS+GLONASS+BeiDou+Galileo four-system model to fully exploit the observations of all these four navigation satellite systems for real-time precise orbit determination, clock estimation and positioning. A rigorous multi-GNSS analysis is performed to achieve the best possible consistency by processing the observations from different GNSS together in one common parameter estimation procedure. Meanwhile, an efficient multi-GNSS real-time precise positioning service system is designed and demonstrated by using the multi-GNSS Experiment, BeiDou Experimental Tracking Network, and International GNSS Service networks including stations all over the world. The statistical analysis of the 6-h predicted orbits show that the radial and cross root mean square (RMS) values are smaller than 10 cm for BeiDou and Galileo, and smaller than 5 cm for both GLONASS and GPS satellites, respectively. The RMS values of the clock differences between real-time and batch-processed solutions for GPS satellites are about 0.10 ns, while the RMS values for BeiDou, Galileo and GLONASS are 0.13, 0.13 and 0.14 ns, respectively. The addition of the BeiDou, Galileo and GLONASS systems to the standard GPS-only processing, reduces the convergence time almost by 70 %, while the positioning accuracy is improved by about 25 %. Some outliers in the GPS-only solutions vanish when multi-GNSS observations are processed simultaneous. The availability and reliability of GPS precise positioning decrease dramatically as the elevation cutoff increases. However, the accuracy of multi-GNSS precise point positioning (PPP) is hardly decreased and few centimeter are still achievable in the horizontal components even with 40 elevation cutoff. At 30 and 40 elevation cutoffs, the availability rates of GPS-only solution drop significantly to only around 70 and 40 %, respectively. However, multi-GNSS PPP can provide precise position estimates continuously (availability rate is more than 99

  5. Accuracy of sea level predictions with lead time of one week: a comparison between Prognocean and MyOcean

    NASA Astrophysics Data System (ADS)

    Swierczynska, Malgorzata; Mizinski, Bartlomiej; Niedzielski, Tomasz

    2015-04-01

    There exist several systems which produce sea level forecasts in real time, with lead times ranging from hours to two weeks in the future. One of the recently developed solutions is Prognocean, the system that has been built and implemented at the University of Wroclaw, Poland. Its main feature is that it uses simple time series models to predict sea level anomaly maps, and does it for lead times ranging from 1 to 14 days with daily update. The empirical data-based models are fitted in real time both to individual grids (polynomial-harmonic model, polynomial-harmonic model combined with autoregressive model, polynomial-harmonic model combined with threshold autoregressive model) and to numerous grids forming a spatial latitude x longitude window of 3˚ x 5˚ (polynomial-harmonic model combined with multivariate autoregressive model). Although their simplicity, the approaches have already been shown to produce sea level anomaly predictions of reasonable accuracy. However, none of the analyses targeted at the comparative study which would present the skills of the Prognocean system against a background of the performance of other systems that use physically-based models. This study aims to fill this gap by comparing Prognocean-based predictions for one week into the future with the corresponding prognoses calculated by MyOcean. The reader is provided with the objectively-calculated set of statistics, presented as maps, which describes prediction errors (mean absolute error, root mean square error, index of agreement) and prediction skills (prediction efficiency, coefficient of determination) of the two systems. The exercise enables to compare the skills of the approaches, and the gridwise comparison allows one to identify areas of superior performance of each system.

  6. Accuracy of travel time distribution (TTD) models as affected by TTD complexity, observation errors, and model and tracer selection

    USGS Publications Warehouse

    Green, Christopher T.; Zhang, Yong; Jurgens, Bryant C.; Starn, J. Jeffrey; Landon, Matthew K.

    2014-01-01

    Analytical models of the travel time distribution (TTD) from a source area to a sample location are often used to estimate groundwater ages and solute concentration trends. The accuracies of these models are not well known for geologically complex aquifers. In this study, synthetic datasets were used to quantify the accuracy of four analytical TTD models as affected by TTD complexity, observation errors, model selection, and tracer selection. Synthetic TTDs and tracer data were generated from existing numerical models with complex hydrofacies distributions for one public-supply well and 14 monitoring wells in the Central Valley, California. Analytical TTD models were calibrated to synthetic tracer data, and prediction errors were determined for estimates of TTDs and conservative tracer (NO3−) concentrations. Analytical models included a new, scale-dependent dispersivity model (SDM) for two-dimensional transport from the watertable to a well, and three other established analytical models. The relative influence of the error sources (TTD complexity, observation error, model selection, and tracer selection) depended on the type of prediction. Geological complexity gave rise to complex TTDs in monitoring wells that strongly affected errors of the estimated TTDs. However, prediction errors for NO3− and median age depended more on tracer concentration errors. The SDM tended to give the most accurate estimates of the vertical velocity and other predictions, although TTD model selection had minor effects overall. Adding tracers improved predictions if the new tracers had different input histories. Studies using TTD models should focus on the factors that most strongly affect the desired predictions.

  7. Efficiency and accuracy of the perturbation response coefficient generation method for whole core comet calculations in BWR and CANDU configurations

    SciTech Connect

    Zhang, D.; Rahnema, F.

    2013-07-01

    The coarse mesh transport method (COMET) is a highly accurate and efficient computational tool which predicts whole-core neutronics behaviors for heterogeneous reactor cores via a pre-computed eigenvalue-dependent response coefficient (function) library. Recently, a high order perturbation method was developed to significantly improve the efficiency of the library generation method. In that work, the method's accuracy and efficiency was tested in a small PWR benchmark problem. This paper extends the application of the perturbation method to include problems typical of the other water reactor cores such as BWR and CANDU bundles. It is found that the response coefficients predicted by the perturbation method for typical BWR bundles agree very well with those directly computed by the Monte Carlo method. The average and maximum relative errors in the surface-to-surface response coefficients are 0.02%-0.05% and 0.06%-0.25%, respectively. For CANDU bundles, the corresponding quantities are 0.01%-0.05% and 0.04% -0.15%. It is concluded that the perturbation method is highly accurate and efficient with a wide range of applicability. (authors)

  8. Time-dependent onshore tsunami response

    USGS Publications Warehouse

    Apotsos, Alex; Gelfenbaum, Guy R.; Jaffe, Bruce E.

    2012-01-01

    While bulk measures of the onshore impact of a tsunami, including the maximum run-up elevation and inundation distance, are important for hazard planning, the temporal evolution of the onshore flow dynamics likely controls the extent of the onshore destruction and the erosion and deposition of sediment that occurs. However, the time-varying dynamics of actual tsunamis are even more difficult to measure in situ than the bulk parameters. Here, a numerical model based on the non-linear shallow water equations is used to examine the effects variations in the wave characteristics, bed slope, and bottom roughness have on the temporal evolution of the onshore flow. Model results indicate that the onshore flow dynamics vary significantly over the parameter space examined. For example, the flow dynamics over steep, smooth morphologies tend to be temporally symmetric, with similar magnitude velocities generated during the run-up and run-down phases of inundation. Conversely, on shallow, rough onshore topographies the flow dynamics tend to be temporally skewed toward the run-down phase of inundation, with the magnitude of the flow velocities during run-up and run-down being significantly different. Furthermore, for near-breaking tsunami waves inundating over steep topography, the flow velocity tends to accelerate almost instantaneously to a maximum and then decrease monotonically. Conversely, when very long waves inundate over shallow topography, the flow accelerates more slowly and can remain steady for a period of time before beginning to decelerate. These results indicate that a single set of assumptions concerning the onshore flow dynamics cannot be applied to all tsunamis, and site specific analyses may be required.

  9. Accurate procedure for deriving UTI at a submilliarcsecond accuracy from Greenwich Sidereal Time or from the stellar angle

    NASA Astrophysics Data System (ADS)

    Capitaine, N.; Gontier, A.-M.

    1993-08-01

    Present observations using modern astrometric techniques are supposed to provide the Earth orientation parameters, and therefore UT1, with an accuracy better than ±1 mas. In practice, UT1 is determined through the intermediary of Greenwich Sidereal Time (GST), using both the conventional relationship between Greenwich Mean Sidereal Time (GMST) and UTl (Aoki et al. 1982) and the so-called "equation of the equinoxes" limited to the first order terms with respect to the nutation quantities. This highly complex relation between sidereal time and UT1 is not accurate at the milliaresecond level which gives rise to spurious terms of milliaresecond amplitude in the derived UTl. A more complete relationship between GST and UT1 has been recommended by Aoki & Kinoshita (1983) and Aoki (1991) taking into account the second order terms in the difference between GST and GM ST, the largest one having an amplitude of 2.64 mas and a 18.6 yr-period. This paper explains how this complete expansion of GST implicitly uses the concept of "nonrotating origin" (NRO) as proposed by Guinot in 1979 and would, therefore, provide a more accurate value of UTl and consequently of the Earth's angular velocity. This paper shows, moreover, that such a procedure would be simplified and conceptually clarified by the explicit use of the NRO as previously proposed (Guinot 1979; Capitaine et al. 1986). The two corresponding options (implicit or explicit use of the NRO) are shown to be equivalent for defining the specific Earth's angle of rotation and then UT1. The of the use of such an accurate procedure which has been proposed in the new IERS standards (McCarthy 1992a) instead of the usual one are estimated for the practical derivation of UT1.

  10. Effect of Storage Time of Extended-Pour and Conventional Alginate Impressions on Dimensional Accuracy of Casts

    PubMed Central

    Rohanian, Ahmad; Ommati Shabestari, Ghasem; Zeighami, Somayeh; Samadi, Mohammad Javad; Shamshiri, Ahmad Reza

    2014-01-01

    Objectives: Some manufacturers claim to have produced new irreversible hydro-colloids that are able to maintain their dimensional stability during storage. The present study evaluated the effect of storage time on dimensional stability of three alginates: Hydrogum 5, Tropicalgin and Alginoplast. Materials and Methods: In this experimental in-vitro trial, a total of 90 alginate impressions were made from a Dentoform model using Hydrogum 5, Tropicalgin and Alginoplast alginates. The impressions were stored in a sealed plastic bag without a damp paper towel for 0, 24, 48, 72 and 120 hours and then poured with type III dental stone. Cross-arch (facial of 6 to facial of 6 on the opposite side) and antero-posterior (distal of right first molar to the ipsilateral central incisor) measurements were made with a digital caliper on the casts. Data were analyzed by two-way and one-way ANOVA and Tukey’s post-hoc test (P<0.05). Results: Alginate type and the pouring time significantly affected the dimensional stability of alginate impressions (both Ps<0.001). Pouring of Hydrogum 5 impressions can be delayed for up to 120 hours without significant dimensional changes. Alginoplast impressions may be poured after 72 hours, but Tropicalgin should be poured immediately and the storage time should not be more than 24 hours. Conclusion: Immediate pouring of alginate impressions provides the highest accuracy in reproducing the teeth and adjacent tissues; however, this study demonstrated that pouring may be delayed for up to five days using extended-pour (Hydrogum 5) alginates. PMID:25628695

  11. Linear Discriminant Analysis Achieves High Classification Accuracy for the BOLD fMRI Response to Naturalistic Movie Stimuli.

    PubMed

    Mandelkow, Hendrik; de Zwart, Jacco A; Duyn, Jeff H

    2016-01-01

    Naturalistic stimuli like movies evoke complex perceptual processes, which are of great interest in the study of human cognition by functional MRI (fMRI). However, conventional fMRI analysis based on statistical parametric mapping (SPM) and the general linear model (GLM) is hampered by a lack of accurate parametric models of the BOLD response to complex stimuli. In this situation, statistical machine-learning methods, a.k.a. multivariate pattern analysis (MVPA), have received growing attention for their ability to generate stimulus response models in a data-driven fashion. However, machine-learning methods typically require large amounts of training data as well as computational resources. In the past, this has largely limited their application to fMRI experiments involving small sets of stimulus categories and small regions of interest in the brain. By contrast, the present study compares several classification algorithms known as Nearest Neighbor (NN), Gaussian Naïve Bayes (GNB), and (regularized) Linear Discriminant Analysis (LDA) in terms of their classification accuracy in discriminating the global fMRI response patterns evoked by a large number of naturalistic visual stimuli presented as a movie. Results show that LDA regularized by principal component analysis (PCA) achieved high classification accuracies, above 90% on average for single fMRI volumes acquired 2 s apart during a 300 s movie (chance level 0.7% = 2 s/300 s). The largest source of classification errors were autocorrelations in the BOLD signal compounded by the similarity of consecutive stimuli. All classifiers performed best when given input features from a large region of interest comprising around 25% of the voxels that responded significantly to the visual stimulus. Consistent with this, the most informative principal components represented widespread distributions of co-activated brain regions that were similar between subjects and may represent functional networks. In light of these

  12. Linear Discriminant Analysis Achieves High Classification Accuracy for the BOLD fMRI Response to Naturalistic Movie Stimuli

    PubMed Central

    Mandelkow, Hendrik; de Zwart, Jacco A.; Duyn, Jeff H.

    2016-01-01

    Naturalistic stimuli like movies evoke complex perceptual processes, which are of great interest in the study of human cognition by functional MRI (fMRI). However, conventional fMRI analysis based on statistical parametric mapping (SPM) and the general linear model (GLM) is hampered by a lack of accurate parametric models of the BOLD response to complex stimuli. In this situation, statistical machine-learning methods, a.k.a. multivariate pattern analysis (MVPA), have received growing attention for their ability to generate stimulus response models in a data-driven fashion. However, machine-learning methods typically require large amounts of training data as well as computational resources. In the past, this has largely limited their application to fMRI experiments involving small sets of stimulus categories and small regions of interest in the brain. By contrast, the present study compares several classification algorithms known as Nearest Neighbor (NN), Gaussian Naïve Bayes (GNB), and (regularized) Linear Discriminant Analysis (LDA) in terms of their classification accuracy in discriminating the global fMRI response patterns evoked by a large number of naturalistic visual stimuli presented as a movie. Results show that LDA regularized by principal component analysis (PCA) achieved high classification accuracies, above 90% on average for single fMRI volumes acquired 2 s apart during a 300 s movie (chance level 0.7% = 2 s/300 s). The largest source of classification errors were autocorrelations in the BOLD signal compounded by the similarity of consecutive stimuli. All classifiers performed best when given input features from a large region of interest comprising around 25% of the voxels that responded significantly to the visual stimulus. Consistent with this, the most informative principal components represented widespread distributions of co-activated brain regions that were similar between subjects and may represent functional networks. In light of these

  13. The relative and absolute timing accuracy of the EPIC-pn camera on XMM-Newton, from X-ray pulsations of the Crab and other pulsars

    NASA Astrophysics Data System (ADS)

    Martin-Carrillo, A.; Kirsch, M. G. F.; Caballero, I.; Freyberg, M. J.; Ibarra, A.; Kendziorra, E.; Lammers, U.; Mukerjee, K.; Schönherr, G.; Stuhlinger, M.; Saxton, R. D.; Staubert, R.; Suchy, S.; Wellbrock, A.; Webb, N.; Guainazzi, M.

    2012-09-01

    Aims: Reliable timing calibration is essential for the accurate comparison of XMM-Newton light curves with those from other observatories, to ultimately use them to derive precise physical quantities. The XMM-Newton timing calibration is based on pulsar analysis. However, because pulsars show both timing noise and glitches, it is essential to monitor these calibration sources regularly. To this end, the XMM-Newton observatory performs observations twice a year of the Crab pulsar to monitor the absolute timing accuracy of the EPIC-pn camera in the fast timing and burst modes. We present the results of this monitoring campaign, comparing XMM-Newton data from the Crab pulsar (PSR B0531+21) with radio measurements. In addition, we use five pulsars (PSR J0537-69, PSR B0540-69, PSR B0833-45, PSR B1509-58, and PSR B1055-52) with periods ranging from 16 ms to 197 ms to verify the relative timing accuracy. Methods: We analysed 38 XMM-Newton observations (0.2-12.0 keV) of the Crab taken over the first ten years of the mission and 13 observations from the five complementary pulsars. All data were processed with SAS, the XMM-Newton Scientific Analysis Software, version 9.0. Epoch-folding techniques coupled with χ2 tests were used to derive relative timing accuracies. The absolute timing accuracy was determined using the Crab data and comparing the time shift between the main X-ray and radio peaks in the phase-folded light curves. Results: The relative timing accuracy of XMM-Newton is found to be better than 10-8. The strongest X-ray pulse peak precedes the corresponding radio peak by 306 ± 9 μs, which agrees with other high-energy observatories such as Chandra, INTEGRAL and RXTE. The derived absolute timing accuracy from our analysis is ± 48 μs.

  14. 6 CFR 5.5 - Timing of responses to requests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 6 Domestic Security 1 2011-01-01 2011-01-01 false Timing of responses to requests. 5.5 Section 5.5 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY DISCLOSURE OF RECORDS AND INFORMATION Freedom of Information Act § 5.5 Timing of responses to requests. (a) In general....

  15. 6 CFR 5.5 - Timing of responses to requests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 6 Domestic Security 1 2012-01-01 2012-01-01 false Timing of responses to requests. 5.5 Section 5.5 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY DISCLOSURE OF RECORDS AND INFORMATION Freedom of Information Act § 5.5 Timing of responses to requests. (a) In general....

  16. 6 CFR 5.5 - Timing of responses to requests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 6 Domestic Security 1 2013-01-01 2013-01-01 false Timing of responses to requests. 5.5 Section 5.5 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY DISCLOSURE OF RECORDS AND INFORMATION Freedom of Information Act § 5.5 Timing of responses to requests. (a) In general....

  17. 10 CFR 1303.107 - Timing of responses to requests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Timing of responses to requests. 1303.107 Section 1303.107 Energy NUCLEAR WASTE TECHNICAL REVIEW BOARD PUBLIC INFORMATION AND REQUESTS § 1303.107 Timing of responses to requests. (a) General. The Board shall normally respond to requests in the order of...

  18. 10 CFR 1303.107 - Timing of responses to requests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Timing of responses to requests. 1303.107 Section 1303.107 Energy NUCLEAR WASTE TECHNICAL REVIEW BOARD PUBLIC INFORMATION AND REQUESTS § 1303.107 Timing of responses to requests. (a) General. The Board shall normally respond to requests in the order of...

  19. 6 CFR 5.5 - Timing of responses to requests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 6 Domestic Security 1 2014-01-01 2014-01-01 false Timing of responses to requests. 5.5 Section 5.5 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY DISCLOSURE OF RECORDS AND INFORMATION Freedom of Information Act § 5.5 Timing of responses to requests. (a) In general....

  20. Linking Response-Time Parameters onto a Common Scale

    ERIC Educational Resources Information Center

    van der Linden, Wim J.

    2010-01-01

    Although response times on test items are recorded on a natural scale, the scale for some of the parameters in the lognormal response-time model (van der Linden, 2006) is not fixed. As a result, when the model is used to periodically calibrate new items in a testing program, the parameter are not automatically mapped onto a common scale. Several…

  1. Hierarchical Diffusion Models for Two-Choice Response Times

    ERIC Educational Resources Information Center

    Vandekerckhove, Joachim; Tuerlinckx, Francis; Lee, Michael D.

    2011-01-01

    Two-choice response times are a common type of data, and much research has been devoted to the development of process models for such data. However, the practical application of these models is notoriously complicated, and flexible methods are largely nonexistent. We combine a popular model for choice response times--the Wiener diffusion…

  2. Testing for Aberrant Behavior in Response Time Modeling

    ERIC Educational Resources Information Center

    Marianti, Sukaesi; Fox, Jean-Paul; Avetisyan, Marianna; Veldkamp, Bernard P.; Tijmstra, Jesper

    2014-01-01

    Many standardized tests are now administered via computer rather than paper-and-pencil format. In a computer-based testing environment, it is possible to record not only the test taker's response to each question (item) but also the amount of time spent by the test taker in considering and answering each item. Response times (RTs) provide…

  3. 45 CFR 612.5 - Timing of responses to requests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 3 2012-10-01 2012-10-01 false Timing of responses to requests. 612.5 Section 612.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION AVAILABILITY OF RECORDS AND INFORMATION § 612.5 Timing of responses to requests. (a) In general. NSF...

  4. 45 CFR 612.5 - Timing of responses to requests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 3 2013-10-01 2013-10-01 false Timing of responses to requests. 612.5 Section 612.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION AVAILABILITY OF RECORDS AND INFORMATION § 612.5 Timing of responses to requests. (a) In general. The NSF and its component, OIG, ordinarily will...

  5. 45 CFR 612.5 - Timing of responses to requests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 3 2014-10-01 2014-10-01 false Timing of responses to requests. 612.5 Section 612.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION AVAILABILITY OF RECORDS AND INFORMATION § 612.5 Timing of responses to requests. (a) In general. The NSF...

  6. 45 CFR 612.5 - Timing of responses to requests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 3 2011-10-01 2011-10-01 false Timing of responses to requests. 612.5 Section 612.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION AVAILABILITY OF RECORDS AND INFORMATION § 612.5 Timing of responses to requests. (a) In general. NSF...

  7. 48 CFR 1505.203 - Publicizing and response time.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Publicizing and response time. 1505.203 Section 1505.203 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY ACQUISITION PLANNING PUBLICIZING CONTRACT ACTIONS Synopses of Proposed Contract Actions 1505.203 Publicizing and response time. (a) The...

  8. 48 CFR 1505.203 - Publicizing and response time.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Publicizing and response time. 1505.203 Section 1505.203 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY ACQUISITION PLANNING PUBLICIZING CONTRACT ACTIONS Synopses of Proposed Contract Actions 1505.203 Publicizing and response time. (a) The...

  9. 10 CFR 1303.107 - Timing of responses to requests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Timing of responses to requests. 1303.107 Section 1303.107 Energy NUCLEAR WASTE TECHNICAL REVIEW BOARD PUBLIC INFORMATION AND REQUESTS § 1303.107 Timing of responses to requests. (a) General. The Board shall normally respond to requests in the order of...

  10. 10 CFR 1303.107 - Timing of responses to requests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Timing of responses to requests. 1303.107 Section 1303.107 Energy NUCLEAR WASTE TECHNICAL REVIEW BOARD PUBLIC INFORMATION AND REQUESTS § 1303.107 Timing of responses to requests. (a) General. The Board shall normally respond to requests in the order of...

  11. 10 CFR 1303.107 - Timing of responses to requests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Timing of responses to requests. 1303.107 Section 1303.107 Energy NUCLEAR WASTE TECHNICAL REVIEW BOARD PUBLIC INFORMATION AND REQUESTS § 1303.107 Timing of responses to requests. (a) General. The Board shall normally respond to requests in the order of their receipt. (b) Acknowledgement of requests....

  12. 6 CFR 5.5 - Timing of responses to requests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 false Timing of responses to requests. 5.5 Section 5.5... INFORMATION Freedom of Information Act § 5.5 Timing of responses to requests. (a) In general. Components... the number of pages involved. If a component does so, it shall advise requesters in its slower...

  13. 40 CFR 1601.24 - Timing of responses to requests.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Timing of responses to requests. 1601.24 Section 1601.24 Protection of Environment CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD PROCEDURES FOR DISCLOSURE OF RECORDS UNDER THE FREEDOM OF INFORMATION ACT Procedures for Requesting and Disclosing Records § 1601.24 Timing of responses...

  14. 40 CFR 1601.24 - Timing of responses to requests.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Timing of responses to requests. 1601.24 Section 1601.24 Protection of Environment CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD PROCEDURES FOR DISCLOSURE OF RECORDS UNDER THE FREEDOM OF INFORMATION ACT Procedures for Requesting and Disclosing Records § 1601.24 Timing of responses...

  15. 40 CFR 1601.24 - Timing of responses to requests.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Timing of responses to requests. 1601.24 Section 1601.24 Protection of Environment CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD PROCEDURES FOR DISCLOSURE OF RECORDS UNDER THE FREEDOM OF INFORMATION ACT Procedures for Requesting and Disclosing Records § 1601.24 Timing of responses...

  16. 18 CFR 1301.5 - Timing of responses to requests.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Timing of responses to requests. 1301.5 Section 1301.5 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY PROCEDURES Freedom of Information Act § 1301.5 Timing of responses to requests. (a) In general, TVA ordinarily shall respond to requests according...

  17. 40 CFR 1601.24 - Timing of responses to requests.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Timing of responses to requests. 1601.24 Section 1601.24 Protection of Environment CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD PROCEDURES FOR DISCLOSURE OF RECORDS UNDER THE FREEDOM OF INFORMATION ACT Procedures for Requesting and Disclosing Records § 1601.24 Timing of responses...

  18. 40 CFR 1601.24 - Timing of responses to requests.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Timing of responses to requests. 1601.24 Section 1601.24 Protection of Environment CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD PROCEDURES FOR DISCLOSURE OF RECORDS UNDER THE FREEDOM OF INFORMATION ACT Procedures for Requesting and Disclosing Records § 1601.24 Timing of responses...

  19. Performance evaluation of response time in ATM LANs

    SciTech Connect

    Chen, H.; Brandt, J.

    1995-12-11

    This contribution compares the response-time performance of ATM LANs using ABR EFCI, UBR FIFO, and UBR with per VC queuing switches. Our study is based on experimental as well as simulation results. We found that, with or without congestion, UBR switches with per VC queuing provide the best response times.

  20. Response Time Variations in an Online Search System.

    ERIC Educational Resources Information Center

    Cooper, Michael D.

    1983-01-01

    Explores response time variations in National Library of Medicine's ELHILL bibliographic search system and analyzes statistical significance of response time in terms of its variations by day of week, hour of day, particular bibliographic file being searched, command issued by user, number of users logged onto system. Ten references are cited.…

  1. Accuracy of PARTwear Inertial Sensor and Optojump Optical Measurement System for Measuring Ground Contact Time During Running.

    PubMed

    Ammann, Rahel; Taube, Wolfgang; Wyss, Thomas

    2016-07-01

    Ammann, R, Taube, W, and Wyss, T. Accuracy of PARTwear inertial sensor and Optojump optical measurement system for measuring ground contact time during running. J Strength Cond Res 30(7): 2057-2063, 2016-The aim of this study was to validate the detection of ground contact time (GCT) during running in 2 differently working systems: a small inertial measurement sensor, PARTwear (PW), worn on the shoe laces, and the optical measurement system, Optojump (OJ), placed on the track. Twelve well-trained subjects performed 12 runs each on an indoor track at speeds ranging from 3.0 to 9.0 m·s. GCT of one step per run (total 144) was simultaneously obtained by the PW, the OJ, and a high-speed video camera (HSC), whereby the latter served as reference system. The sampling rate was 1,000 Hz for all methods. Compared with the HSC, the PW and the OJ systems underestimated GCT by -1.3 ± 6.1% and -16.5 ± 6.7% (p-values ≤ 0.05), respectively. The intraclass correlation coefficients between PW and HSC and between OJ and HSC were 0.984 and 0.853 (p-values < 0.001), respectively. Despite the constant systematic underestimation of GCT, analyses indicated that PW successfully recorded GCT over a wide range of speeds. However, results showed only moderate validity for the OJ system, with increasing errors when speed decreased. In conclusion, the PW proved to be a highly useful and valid application, and its use can be recommended not only for laboratory settings but also for field applications. In contrast, data on GCT obtained by OJ during running must be treated with caution, specifically when running speed changes or when comparisons are made with GCT data collected by other measurement systems. PMID:26677827

  2. Efficient allocation of heterogeneous response times in information spreading process

    NASA Astrophysics Data System (ADS)

    Cui, Ai-Xiang; Wang, Wei; Tang, Ming; Fu, Yan; Liang, Xiaoming; Do, Younghae

    2014-09-01

    Recently, the impacts of spatiotemporal heterogeneities of human activities on spreading dynamics have attracted extensive attention. In this paper, we intend to understand how the heterogeneous distribution of response times at the individual level influences information spreading. Based on the uncorrelated scale-free networks without degree-degree correlation, we study the susceptible-infected spreading dynamics with adjustable power-law response time distribution, and find that the stronger the heterogeneity of response times is, the faster the information spreading is in the early and middle stages. Following a given heterogeneity, the procedure of reducing the correlation between the response times and degrees of individuals can also accelerate the spreading dynamics in the early and middle stages. However, the dynamics in the late stage is slightly more complicated, and there is an optimal value of the full prevalence time (i.e., the time for full infection on a network) changing with the heterogeneity of response times and the response time-degree correlation, respectively. The optimal phenomena result from the efficient allocation of heterogeneous response times.

  3. Detection of Residual Brain Arteriovenous Malformations after Radiosurgery: Diagnostic Accuracy of Contrast-Enhanced Three-Dimensional Time of Flight MR Angiography at 3.0 Tesla

    PubMed Central

    Lee, Kyoung Eun; Choi, Jin Woo; Choi, Byung Se; Lee, Deok Hee; Kim, Sang Joon; Kwon, Do Hoon

    2009-01-01

    Objective Although three-dimensional time-of-flight magnetic resonance angiography (3D TOF-MRA) is used frequently as a follow-up tool to assess the response of arteriovenous malformations (AVMs) after radiosurgery, the diagnostic accuracy of 3D TOF-MRA is not well known. We evaluated the diagnostic accuracy of contrast-enhanced 3D TOF-MRA at 3.0 Tesla for the detection of residual AVMs. Materials and Methods This study included 32 AVMs from 32 patients who had been treated with radiosurgery (males/females: 21/11; average patient age, 33.1 years). The time interval between radiosurgery and MRA was an average of 35.3 months (range, 12-88 months). Three-dimensional TOF-MRA was obtained at a magnetic field strength of 3.0 Tesla after infusion of contrast media, with a measured voxel size of 0.40 × 0.80 × 1.4 (0.45) mm3 and a reconstructed voxel size of 0.27 × 0.27 × 0.70 (0.05) mm3 after zero-filling. X-ray angiography was performed as the reference of standard within six months after MRA (an average of two months). To determine the presence of a residual AVM, the source images of 3D TOF-MRA were independently reviewed, focusing on the presence of abnormally hyperintense fine tangled or tubular structures with continuity as seen on consecutive slices by two observers blinded to the X-ray angiography results. Results A residual AVM was identified in 10 patients (10 of 32, 31%) on X-ray angiography. The inter-observer agreement for MRA was excellent (κ= 0.813). For the detection of a residual AVM after radiosurgery as determined by observer 1 and observer 2, the source images of MRA had an overall sensitivity of 100%/90% (10 of 10, 9 of 10), specificity of 68%/68% (15 of 22, 15 of 22), positive predictive value of 59%/56% (10 of 17, 9 of 16), negative predictive value of 100%/94% (15 of 15, 15 of 16) and diagnostic accuracy of 78%/75% (25 of 32, 24 of 32), respectively. Conclusion The sensitivity of contrast-enhanced 3D TOF-MRA at 3.0 Tesla is high but the

  4. Increasing the accuracy and temporal resolution of two-filter radon-222 measurements by correcting for the instrument response

    NASA Astrophysics Data System (ADS)

    Griffiths, Alan D.; Chambers, Scott D.; Williams, Alastair G.; Werczynski, Sylvester

    2016-06-01

    Dual-flow-loop two-filter radon detectors have a slow time response, which can affect the interpretation of their output when making continuous observations of near-surface atmospheric radon concentrations. While concentrations are routinely reported hourly, a calibrated model of detector performance shows that ˜ 40 % of the signal arrives more than an hour after a radon pulse is delivered. After investigating several possible ways to correct for the detector's slow time response, we show that a Bayesian approach using a Markov chain Monte Carlo sampler is an effective method. After deconvolution, the detector's output is redistributed into the appropriate counting interval and a 10 min temporal resolution can be achieved under test conditions when the radon concentration is controlled. In the case of existing archived observations, collected under less ideal conditions, the data can be retrospectively reprocessed at 30 min resolution. In one case study, we demonstrate that a deconvolved radon time series was consistent with the following: measurements from a fast-response carbon dioxide monitor; grab samples from an aircraft; and a simple mixing height model. In another case study, during a period of stable nights and days with well-developed convective boundary layers, a bias of 18 % in the mean daily minimum radon concentration was eliminated by correcting for the instrument response.

  5. Passenger comfort response times as a function of aircraft motion

    NASA Technical Reports Server (NTRS)

    Rinalducci, E. J.

    1975-01-01

    The relationship between a passenger's response time of changes in level of comfort experienced as a function of aircraft motion was examined. The aircraft used in this investigation was capable of providing a wide range of vertical and transverse accelerations by means of direct lift flap control surfaces and side force generator surfaces in addition to normal control surfaces. Response times to changes in comfort were recorded along with the passenger's rating of comfort on a five point scale. In addition, a number of aircraft motion variables including vertical and transverse accelerations were also recorded. Results indicate some relationship between human comfort response times to reaction time data.

  6. 10 CFR 9.31 - Extension of time for response.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Extension of time for response. 9.31 Section 9.31 Energy NUCLEAR REGULATORY COMMISSION PUBLIC RECORDS Freedom of Information Act Regulations § 9.31 Extension of time for response. (a) In unusual circumstances defined in § 9.13, the NRC may extend the time limits prescribed in § 9.25 or § 9.29 by not...

  7. Computer Response Time Measurements of Mood, Fatigue and Symptom Scale Items: Implications for Scale Response Time Uses.

    ERIC Educational Resources Information Center

    Ryman, David H.; And Others

    1988-01-01

    Describes study conducted with U.S. Marine Corps enlisted personnel to measure response time to computer-administered questionnaire items, and to evaluate how measurement of response time might be useful in various research areas. Topics addressed include mood states; the occurrence of straight lining; and experimental effects of sleep loss and…

  8. Accuracy of pregnancy diagnosis and prediction of foetal numbers in sheep with linear-array real-time ultrasound scanning.

    PubMed

    Taverne, M A; Lavoir, M C; van Oord, R; van der Weyden, G C

    1985-10-01

    Pregnancy diagnosis was carried out in sheep by means of transabdominal linear-array real-time ultrasound scanning. Animals were restrained standing, and the transducer was placed on the hairless area of the ventral abdominal wall just in front of the udder. Of a total of 818 tests, 724 were performed between days 29 and 89 of pregnancy, 598 animals subsequently lambed and 126 were non-lambing animals. Only 8 of these tests were wrong: 3 false positive and 5 false negative diagnoses. Sensitivity, specificity, positive- and negative predictive values for these tests were 99.2%, 97.6%, 99.5%, and 96% respectively. There was evidence to indicate that the three false positive tests were caused by foetal mortality or unobserved abortions that took place after testing. Only 2 of the 5 false negative tests were carried out after day 39 of gestation. Counting of foetal numbers (1, 2 or 3) was performed in only some animals (n = 210) between days 45 and 77 of gestation. Three groups of animals (A: 89 ewes; B: 27 PMSG-treated ewes; C: 94 ewes) were analyzed separately. Overall accuracy of all predictions was 83.1%, 37.0% and 78.7% for the 3 groups respectively. Animals in group B produced only 3 or more lambs. Sensitivity of the countings of singles, twins and triplets or more were 90.4%, 90.4% and 50% respectively for the animals from group A and 91.9%, 86% and 21.4% for the animals from group C.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3907116

  9. In silico instrumental response correction improves precision of label-free proteomics and accuracy of proteomics-based predictive models.

    PubMed

    Lyutvinskiy, Yaroslav; Yang, Hongqian; Rutishauser, Dorothea; Zubarev, Roman A

    2013-08-01

    In the analysis of proteome changes arising during the early stages of a biological process (e.g. disease or drug treatment) or from the indirect influence of an important factor, the biological variations of interest are often small (∼10%). The corresponding requirements for the precision of proteomics analysis are high, and this often poses a challenge, especially when employing label-free quantification. One of the main contributors to the inaccuracy of label-free proteomics experiments is the variability of the instrumental response during LC-MS/MS runs. Such variability might include fluctuations in the electrospray current, transmission efficiency from the air-vacuum interface to the detector, and detection sensitivity. We have developed an in silico post-processing method of reducing these variations, and have thus significantly improved the precision of label-free proteomics analysis. For abundant blood plasma proteins, a coefficient of variation of approximately 1% was achieved, which allowed for sex differentiation in pooled samples and ≈90% accurate differentiation of individual samples by means of a single LC-MS/MS analysis. This method improves the precision of measurements and increases the accuracy of predictive models based on the measurements. The post-acquisition nature of the correction technique and its generality promise its widespread application in LC-MS/MS-based methods such as proteomics and metabolomics. PMID:23589346

  10. Improving Item Response Theory Model Calibration by Considering Response Times in Psychological Tests

    ERIC Educational Resources Information Center

    Ranger, Jochen; Kuhn, Jorg-Tobias

    2012-01-01

    Research findings indicate that response times in personality scales are related to the trait level according to the so-called speed-distance hypothesis. Against this background, Ferrando and Lorenzo-Seva proposed a latent trait model for the responses and response times in a test. The model consists of two components, a standard item response…

  11. An efficient finite-difference method with high-order accuracy in both time and space domains for modelling scalar-wave propagation

    NASA Astrophysics Data System (ADS)

    Tan, Sirui; Huang, Lianjie

    2014-05-01

    For modelling large-scale 3-D scalar-wave propagation, the finite-difference (FD) method with high-order accuracy in space but second-order accuracy in time is widely used because of its relatively low requirements of computer memory. We develop a novel staggered-grid (SG) FD method with high-order accuracy not only in space, but also in time, for solving 2- and 3-D scalar-wave equations. We determine the coefficients of the FD operator in the joint time-space domain to achieve high-order accuracy in time while preserving high-order accuracy in space. Our new FD scheme is based on a stencil that contains a few more grid points than the standard stencil. It is 2M-th-order accurate in space and fourth-order accurate in time when using 2M grid points along each axis and wavefields at one time step as the standard SGFD method. We validate the accuracy and efficiency of our new FD scheme using dispersion analysis and numerical modelling of scalar-wave propagation in 2- and 3-D complex models with a wide range of velocity contrasts. For media with a velocity contrast up to five, our new FD scheme is approximately two times more computationally efficient than the standard SGFD scheme with almost the same computer-memory requirement as the latter. Further numerical experiments demonstrate that our new FD scheme loses its advantages over the standard SGFD scheme if the velocity contrast is 10. However, for most large-scale geophysical applications, the velocity contrasts often range approximately from 1 to 3. Our new method is thus particularly useful for large-scale 3-D scalar-wave modelling and full-waveform inversion.

  12. Field inter-comparison of two high-accuracy fast-response spectroscopic sensors of carbon dioxide

    NASA Astrophysics Data System (ADS)

    Flowers, B. A.; Powers, H. H.; Dubey, M. K.; McDowell, N. G.

    2011-09-01

    Tunable diode laser absorption (TDL) and cavity ring-down spectroscopic (CRDS) sensors for atmospheric carbon dioxide were co-deployed during summer and fall of 2010 in the field at Los Alamos National Laboratory. Both sensors were characterized for accuracy and precision for ambient carbon dioxide measurements at ground level and are compared using both laboratory and atmospheric data. After a four point laboratory cross calibration, the mean [12C16O2]TDL = 392.05 ± 8.92 ppm and [12C16O2]CRDS' = 392.22 ± 9.05 ppm between 29 July and 16 August 2010 (mean difference = 0.04 ± 0.04 ppm). The slope of the cross-calibrated linear regression analysis between the two sensors is 1.000. The CRDS sensor is capable of measuring ambient [12C16O2] to a relative precision of 23 ppb Hz-1/2 for a 1-min time constant and this decreases to 6.5 ppb Hz-1/2 for a 58-min time constant. At one and 58-min time constants, the TDL exhibits precisions of 29 ppb Hz-1/2 and 53 ppb Hz-1/2. The CRDS is compact, fast, and stable. The TDL is larger and requires frequent calibrations that limit its time resolution. Field observations show that 1-min averaged data measured by the two instruments agree almost perfectly, for the 19-day period the CRDS/TDL ratio is a Gaussian distribution at x0 = 1.000 ± 3.38 × 10-5. The sensors also exhibit consistent hourly averaged diurnal values underscoring the interplay of biological, anthropogenic, and transport processes regulating CO2 at the site.

  13. Real time quality control of meteorological data used in SRP's emergency response system

    SciTech Connect

    Pendergast, M.M.

    1980-05-01

    The Savannah River Laboratory's WIND minicomputer system allows quick and accurate assessment of an accidental release at the Savannah River Plant using data from eight meteorological towers. The accuracy of the assessment is largely determined by the accuracy of the meteorological data; therefore quality control is important in an emergency response system. Real-time quality control of this data will be added to the WIND system to automatically identify inaccurate data. Currently, the system averages the measurements from the towers to minimize the influence of inaccurate data being used in calculations. The computer code used in the real-time quality control has been previously used to identify inaccurate measurements from the archived tower data.

  14. Improved design provides faster response time in photomultiplier

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Dynamic Crossed-Field Electron Multiplying /DCFEM/ light demodulator avoids the normal response time limitations inherent in static field devices by using time varying crossed electric and static magnetic fields. This eliminates the transit time spread that affects electrons as they proceed along the secondary emission stages of the tube.

  15. Thermal emittance and response time of a cesium antimonide photocathode

    NASA Astrophysics Data System (ADS)

    Cultrera, Luca; Bazarov, Ivan; Bartnik, Adam; Dunham, Bruce; Karkare, Siddharth; Merluzzi, Richard; Nichols, Matthew

    2011-10-01

    Measurements of the intrinsic emittance and response time of a Cs3Sb photocathode are presented. The emittance is obtained with a solenoid scan technique using a high voltage dc photoemission gun. Photoemission response time is evaluated using a RF deflecting cavity synchronized to a picosecond laser pulse train. We find that Cs3Sb has both small mean transverse energy, 160 ± 10 meV at 532 nm laser wavelength, and a prompt response time (below the resolution of our measurement) making it a suitable material for high brightness electron photoinjectors.

  16. Assessing recognition memory using confidence ratings and response times.

    PubMed

    Weidemann, Christoph T; Kahana, Michael J

    2016-04-01

    Classification of stimuli into categories (such as 'old' and 'new' in tests of recognition memory or 'present' versus 'absent' in signal detection tasks) requires the mapping of internal signals to discrete responses. Introspective judgements about a given choice response are regularly employed in research, legal and clinical settings in an effort to measure the signal that is thought to be the basis of the classification decision. Correlations between introspective judgements and task performance suggest that such ratings often do convey information about internal states that are relevant for a given task, but well-known limitations of introspection call the fidelity of this information into question. We investigated to what extent response times can reveal information usually assessed with explicit confidence ratings. We quantitatively compared response times to confidence ratings in their ability to qualify recognition memory decisions and found convergent results suggesting that much of the information from confidence ratings can be obtained from response times. PMID:27152209

  17. A Mixture Rasch Model with Item Response Time Components

    ERIC Educational Resources Information Center

    Meyer, J. Patrick

    2010-01-01

    An examinee faced with a test item will engage in solution behavior or rapid-guessing behavior. These qualitatively different test-taking behaviors bias parameter estimates for item response models that do not control for such behavior. A mixture Rasch model with item response time components was proposed and evaluated through application to real…

  18. A Mechanism for Error Detection in Speeded Response Time Tasks

    ERIC Educational Resources Information Center

    Holroyd, Clay B.; Yeung, Nick; Coles, Michael G. H.; Cohen, Jonathan D.

    2005-01-01

    The concept of error detection plays a central role in theories of executive control. In this article, the authors present a mechanism that can rapidly detect errors in speeded response time tasks. This error monitor assigns values to the output of cognitive processes involved in stimulus categorization and response generation and detects errors…

  19. Grade of Membership Response Time Model for Detecting Guessing Behaviors

    ERIC Educational Resources Information Center

    Pokropek, Artur

    2016-01-01

    A response model that is able to detect guessing behaviors and produce unbiased estimates in low-stake conditions using timing information is proposed. The model is a special case of the grade of membership model in which responses are modeled as partial members of a class that is affected by motivation and a class that responds only according to…

  20. Response time to colored stimuli in the full visual field

    NASA Technical Reports Server (NTRS)

    Haines, R. F.; Dawson, L. M.; Galvan, T.; Reid, L. M.

    1975-01-01

    Peripheral visual response time was measured in seven dark adapted subjects to the onset of small (45' arc diam), brief (50 msec), colored (blue, yellow, green, red) and white stimuli imaged at 72 locations within their binocular field of view. The blue, yellow, and green stimuli were matched for brightness at about 2.6 sub log 10 units above their absolute light threshold, and they appeared at an unexpected time and location. These data were obtained to provide response time and no-response data for use in various design disciplines involving instrument panel layout. The results indicated that the retina possesses relatively concentric regions within each of which mean response time can be expected to be of approximately the same duration. These regions are centered near the fovea and extend farther horizontally than vertically. Mean foveal response time was fastest for yellow and slowest for blue. Three and one-half percent of the total 56,410 trials presented resulted in no-responses. Regardless of stimulus color, the lowest percentage of no-responses occurred within 30 deg arc from the fovea and the highest within 40 deg to 80 deg arc below the fovea.

  1. Peripheral visual response time and visual display layout

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1974-01-01

    Experiments were performed on a group of 42 subjects in a study of their peripheral visual response time to visual signals under positive acceleration, during prolonged bedrest, at passive 70 deg headup body lift, under exposures to high air temperatures and high luminance levels, and under normal stress-free laboratory conditions. Diagrams are plotted for mean response times to white, red, yellow, green, and blue stimuli under different conditions.

  2. Performance evaluation and accuracy of passive capillary samplers (PCAPs) for estimating real-time drainage water fluxes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Successful monitoring of pollutant transport through the soil profile requires accurate, reliable, and appropriate instrumentation to measure amount of drainage water or flux within the vadose layer. We evaluated the performance and accuracy of automated passive capillary wick samplers (PCAPs) for ...

  3. The Episodic Engram Transformed: Time Reduces Retrieval-Related Brain Activity but Correlates It with Memory Accuracy

    ERIC Educational Resources Information Center

    Furman, Orit; Mendelsohn, Avi; Dudai, Yadin

    2012-01-01

    We took snapshots of human brain activity with fMRI during retrieval of realistic episodic memory over several months. Three groups of participants were scanned during a memory test either hours, weeks, or months after viewing a documentary movie. High recognition accuracy after hours decreased after weeks and remained at similar levels after…

  4. Improved time response for large area microchannel plate photomultiplier tubes in fusion diagnostics

    SciTech Connect

    Milnes, J. S. Conneely, T. M.; Howorth, J.; Horsfield, C. J.

    2014-11-15

    Fusion diagnostics that utilise high speed scintillators often need to capture a large area of light with a high degree of time accuracy. Microchannel plate (MCP) photomultiplier tubes (PMTs) are recognised as the leading device for capturing fast optical signals. However, when manufactured in their traditional proximity focused construction, the time response performance is reduced as the active area increases. This is due to two main factors: the capacitance of a large anode and the difficulty of obtaining small pore MCPs with a large area. Collaboration between Photek and AWE has produced prototype devices that combine the excellent time response of small area MCP-PMTs with a large active area by replacing the traditional proximity-gap front section with an electro-optically focused photocathode to MCP. We present results from both single and double MCP devices with a 40 mm diameter active area and show simulations for the 100 mm device being built this year.

  5. Improved time response for large area microchannel plate photomultiplier tubes in fusion diagnostics

    NASA Astrophysics Data System (ADS)

    Milnes, J. S.; Horsfield, C. J.; Conneely, T. M.; Howorth, J.

    2014-11-01

    Fusion diagnostics that utilise high speed scintillators often need to capture a large area of light with a high degree of time accuracy. Microchannel plate (MCP) photomultiplier tubes (PMTs) are recognised as the leading device for capturing fast optical signals. However, when manufactured in their traditional proximity focused construction, the time response performance is reduced as the active area increases. This is due to two main factors: the capacitance of a large anode and the difficulty of obtaining small pore MCPs with a large area. Collaboration between Photek and AWE has produced prototype devices that combine the excellent time response of small area MCP-PMTs with a large active area by replacing the traditional proximity-gap front section with an electro-optically focused photocathode to MCP. We present results from both single and double MCP devices with a 40 mm diameter active area and show simulations for the 100 mm device being built this year.

  6. Improved time response for large area microchannel plate photomultiplier tubes in fusion diagnostics.

    PubMed

    Milnes, J S; Horsfield, C J; Conneely, T M; Howorth, J

    2014-11-01

    Fusion diagnostics that utilise high speed scintillators often need to capture a large area of light with a high degree of time accuracy. Microchannel plate (MCP) photomultiplier tubes (PMTs) are recognised as the leading device for capturing fast optical signals. However, when manufactured in their traditional proximity focused construction, the time response performance is reduced as the active area increases. This is due to two main factors: the capacitance of a large anode and the difficulty of obtaining small pore MCPs with a large area. Collaboration between Photek and AWE has produced prototype devices that combine the excellent time response of small area MCP-PMTs with a large active area by replacing the traditional proximity-gap front section with an electro-optically focused photocathode to MCP. We present results from both single and double MCP devices with a 40 mm diameter active area and show simulations for the 100 mm device being built this year. PMID:25430347

  7. The Screening Accuracy of the Parent and Teacher-Reported Social Responsiveness Scale (SRS): Comparison with the 3Di and ADOS

    ERIC Educational Resources Information Center

    Duvekot, Jorieke; van der Ende, Jan; Verhulst, Frank C.; Greaves-Lord, Kirstin

    2015-01-01

    The screening accuracy of the parent and teacher-reported Social Responsiveness Scale (SRS) was compared with an autism spectrum disorder (ASD) classification according to (1) the Developmental, Dimensional, and Diagnostic Interview (3Di), (2) the Autism Diagnostic Observation Schedule (ADOS), (3) both the 3Di and ADOS, in 186 children referred to…

  8. Conceptual Question Response Times in Peer Instruction Classrooms

    ERIC Educational Resources Information Center

    Miller, Kelly; Lasry, Nathaniel; Lukoff, Brian; Schell, Julie; Mazur, Eric

    2014-01-01

    Classroom response systems are widely used in interactive teaching environments as a way to engage students by asking them questions. Previous research on the time taken by students to respond to conceptual questions has yielded insights on how students think and change conceptions. We measure the amount of time students take to respond to…

  9. A Conditional Joint Modeling Approach for Locally Dependent Item Responses and Response Times

    ERIC Educational Resources Information Center

    Meng, Xiang-Bin; Tao, Jian; Chang, Hua-Hua

    2015-01-01

    The assumption of conditional independence between the responses and the response times (RTs) for a given person is common in RT modeling. However, when the speed of a test taker is not constant, this assumption will be violated. In this article we propose a conditional joint model for item responses and RTs, which incorporates a covariance…

  10. Transient electromagnetic responses during the transmitter on-time

    NASA Astrophysics Data System (ADS)

    Schultz, Gregory M.; Miller, Jonathan S.; Song, Lin-Ping; Pasion, Leonard

    2010-04-01

    Current time-domain electromagnetic induction instruments generally only utilize data acquired after the cessation of the transmitted field. During this "off time", signals are dominated by induced eddy currents and magnetic surface modes, but do not fully capture the magnetostatic response of permeable and conductive metallic ordnance. In this paper, we investigate the response of EMI systems that measure signals during excitation of the primary magnetic field (the so-called "on-time"). Our analysis shows that on-time signals have great potential to yield useful information that is not often exploited in current EMI systems. We compare analytical models to data from state-of-the-art time-domain EM sensors that have the capability to sample receivers during the on-time. We present modeling results that represent the responses from different current ramps and on-time waveforms for objects and ground. We consider target and clutter objects and grounds having a range of material properties, shapes and sizes, and configurations and investigate signal processing and inversion methods for target detection and discrimination. Specifically, correlations between on-time and off-time signals are shown to be a powerful tool for discriminating ferrous and non-ferrous metallic objects.

  11. Conceptual question response times in Peer Instruction classrooms

    NASA Astrophysics Data System (ADS)

    Miller, Kelly; Lasry, Nathaniel; Lukoff, Brian; Schell, Julie; Mazur, Eric

    2014-12-01

    Classroom response systems are widely used in interactive teaching environments as a way to engage students by asking them questions. Previous research on the time taken by students to respond to conceptual questions has yielded insights on how students think and change conceptions. We measure the amount of time students take to respond to in-class, conceptual questions [ConcepTests (CTs)] in two introductory physics courses taught using Peer Instruction and use item response theory to determine the difficulty of the CTs. We examine response time differences between correct and incorrect answers both before and after the peer discussion for CTs of varying difficulty. We also determine the relationship between response time and student performance on a standardized test of incoming physics knowledge, precourse self-efficacy, and gender. Our data reveal three results of interest. First, response time for correct answers is significantly faster than for incorrect answers, both before and after peer discussion, especially for easy CTs. Second, students with greater incoming physics knowledge and higher self-efficacy respond faster in both rounds. Third, there is no gender difference in response rate after controlling for incoming physics knowledge scores, although males register significantly more attempts before committing to a final answer than do female students. These results provide insight into effective CT pacing during Peer Instruction. In particular, in order to maintain a pace that keeps everyone engaged, students should not be given too much time to respond. When around 80% of the answers are in, the ratio of correct to incorrect responses rapidly approaches levels indicating random guessing and instructors should close the poll.

  12. Quantifying and comparing dynamic predictive accuracy of joint models for longitudinal marker and time-to-event in presence of censoring and competing risks.

    PubMed

    Blanche, Paul; Proust-Lima, Cécile; Loubère, Lucie; Berr, Claudine; Dartigues, Jean-François; Jacqmin-Gadda, Hélène

    2015-03-01

    Thanks to the growing interest in personalized medicine, joint modeling of longitudinal marker and time-to-event data has recently started to be used to derive dynamic individual risk predictions. Individual predictions are called dynamic because they are updated when information on the subject's health profile grows with time. We focus in this work on statistical methods for quantifying and comparing dynamic predictive accuracy of this kind of prognostic models, accounting for right censoring and possibly competing events. Dynamic area under the ROC curve (AUC) and Brier Score (BS) are used to quantify predictive accuracy. Nonparametric inverse probability of censoring weighting is used to estimate dynamic curves of AUC and BS as functions of the time at which predictions are made. Asymptotic results are established and both pointwise confidence intervals and simultaneous confidence bands are derived. Tests are also proposed to compare the dynamic prediction accuracy curves of two prognostic models. The finite sample behavior of the inference procedures is assessed via simulations. We apply the proposed methodology to compare various prediction models using repeated measures of two psychometric tests to predict dementia in the elderly, accounting for the competing risk of death. Models are estimated on the French Paquid cohort and predictive accuracies are evaluated and compared on the French Three-City cohort. PMID:25311240

  13. Verification of the accuracy of GEM-L2 in response to criticism by Lambeck and Coleman

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.

    1984-01-01

    The objective was to evaluate the accuracy of the Goddard Earth Model (GEM)-L2 and its improvement in estimating Lageos orbits in order to provide better baselines for plate tectonics, improved polar motion and Earth rotation. Analyses and comparisons with other models are made to verify accuracy in contrast to the Lambeck and Coleman result which denied the authors' accuracy estimates. The analysis presented completely verifies the accuracy of the GEM-L2 model and disproves the statistical methods of Lambeck and Coleman rejecting the accuracy of GEM-L2 as published in their report. The baselines derived from Lageos with GEM-L2 were estimated to have a 2 cm uncertainty due to the errors in the GEM-L2 gravity model which is supported by the results given. The calibration tests indicate that the errors in GEM-L2 should be reduced by about 30 percent which is in the opposite direction to the result obtained by Lambeck and Coleman.

  14. The use of multiple versus single assessment time points to improve screening accuracy in identifying children at risk for later serious antisocial behavior.

    PubMed

    Petras, Hanno; Buckley, Jacquelyn A; Leoutsakos, Jeannie-Marie S; Stuart, Elizabeth A; Ialongo, Nicholas S

    2013-10-01

    Guided by Kraemer et al.'s (Psychological Methods, 3:257-271, 1999) framework for measuring the potency of risk factors, we sought to improve on the classification accuracy reported in Petras et al. (Journal of the American Academy of Child and Adolescent Psychiatry 43:88-96, 2004a) and Petras et al. (Journal of the American Academy of Child and Adolescent Psychiatry 44:790-797, 2005) by using multiple as opposed to single point in time assessments of early aggressive and disruptive behavior in the classification of youth who would likely benefit from targeted preventive interventions. Different from Petras et al. (2004a, 2005), the outcome used in this study included serious antisocial behavior in young adulthood as well as in adolescence. Among males, the use of multiple time points did not yield greater classification accuracy than the highest single time points, that is, third and fifth grades. For females, although fifth grade represented the best single time point in terms of classification accuracy, no significant association was found between earlier time points and the later outcome, rendering a test of the multiple time points hypothesis moot. The findings presented in this study have strong implications for the design of targeted intervention for violence prevention, indicating that the screening quality based on aggression ratings during the elementary years is rather modest, particularly for females. PMID:23408279

  15. Modeling operators' emergency response time for chemical processing operations.

    PubMed

    Murray, Susan L; Harputlu, Emrah; Mentzer, Ray A; Mannan, M Sam

    2014-01-01

    Operators have a crucial role during emergencies at a variety of facilities such as chemical processing plants. When an abnormality occurs in the production process, the operator often has limited time to either take corrective actions or evacuate before the situation becomes deadly. It is crucial that system designers and safety professionals can estimate the time required for a response before procedures and facilities are designed and operations are initiated. There are existing industrial engineering techniques to establish time standards for tasks performed at a normal working pace. However, it is reasonable to expect the time required to take action in emergency situations will be different than working at a normal production pace. It is possible that in an emergency, operators will act faster compared to a normal pace. It would be useful for system designers to be able to establish a time range for operators' response times for emergency situations. This article develops a modeling approach to estimate the time standard range for operators taking corrective actions or following evacuation procedures in emergency situations. This will aid engineers and managers in establishing time requirements for operators in emergency situations. The methodology used for this study combines a well-established industrial engineering technique for determining time requirements (predetermined time standard system) and adjustment coefficients for emergency situations developed by the authors. Numerous videos of workers performing well-established tasks at a maximum pace were studied. As an example, one of the tasks analyzed was pit crew workers changing tires as quickly as they could during a race. The operations in these videos were decomposed into basic, fundamental motions (such as walking, reaching for a tool, and bending over) by studying the videos frame by frame. A comparison analysis was then performed between the emergency pace and the normal working pace operations

  16. Response-time optimization of rule-based expert systems

    NASA Astrophysics Data System (ADS)

    Zupan, Blaz; Cheng, Albert M. K.

    1994-03-01

    Real-time rule-based decision systems are embedded AI systems and must make critical decisions within stringent timing constraints. In the case where the response time of the rule- based system is not acceptable, it has to be optimized to meet both timing and integrity constraints. This paper describes a novel approach to reduce the response time of rule-based expert systems. Our optimization method is twofold: the first phase constructs the reduced cycle-free finite state transition system corresponding to the input rule-based system, and the second phase further refines the constructed transition system using the simulated annealing approach. The method makes use of rule-base system decomposition, concurrency, and state- equivalency. The new and optimized system is synthesized from the derived transition system. Compared with the original system, the synthesized system has fewer number of rule firings to reach the fixed point, is inherently stable, and has no redundant rules.

  17. Peripheral visual response time and retinal luminance-area relations

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1975-01-01

    Experiments were undertaken to elucidate the stimulus luminance-retinal area relationship that underlies response time (RT) behavior. Mean RT was significantly faster to stimuli imaged beyond about 70 deg of arc from the fovea when their luminance was increased by an amount equal to the foveal stimulus luminance multiplied by the cosine of the angle between the peripheral stimuli and the line of sight. This and additional data are discussed in relation to previous psychophysical data and to possible response mechanisms.

  18. Maternal Accuracy and Behavior in Anticipating Children's Responses to Novelty: Relations to Fearful Temperament and Implications for Anxiety Development

    ERIC Educational Resources Information Center

    Kiel, Elizabeth J.; Buss, Kristin A.

    2010-01-01

    Previous research has suggested that mothers' behaviors may serve as a mechanism in the development from toddler fearful temperament to childhood anxiety. The current study examined the maternal characteristic of accuracy in predicting toddlers' distress reactions to novelty in relation to temperament, parenting, and anxiety development.…

  19. Optimizing geometric accuracy of four-dimensional CT scans acquired using the wall- and couch-mounted Varian® Real-time Position Management™ camera systems

    PubMed Central

    Irvine, D M; Cole, A J; Hanna, G G; McGarry, C K

    2015-01-01

    Objective: The aim of this study was to identify sources of anatomical misrepresentation owing to the location of camera mounting, tumour motion velocity and image processing artefacts in order to optimize the four-dimensional CT (4DCT) scan protocol and improve geometrical–temporal accuracy. Methods: A phantom with an imaging insert was driven with a sinusoidal superior–inferior motion of varying amplitude and period for 4DCT scanning. The length of a high-density cube within the insert was measured using treatment planning software to determine the accuracy of its spatial representation. Scan parameters were varied, including the tube rotation period and the cine time between reconstructed images. A CT image quality phantom was used to measure various image quality signatures under the scan parameters tested. Results: No significant difference in spatial accuracy was found for 4DCT scans carried out using the wall- or couch-mounted camera for sinusoidal target motion. Greater spatial accuracy was found for 4DCT scans carried out using a tube rotation speed of 0.5 s rather than 1.0 s. The reduction in image quality when using a faster rotation speed was not enough to require an increase in patient dose. Conclusion: The 4DCT accuracy may be increased by optimizing scan parameters, including choosing faster tube rotation speeds. Peak misidentification in the recorded breathing trace may lead to spatial artefacts, and this risk can be reduced by using a couch-mounted infrared camera. Advances in knowledge: This study explicitly shows that 4DCT scan accuracy is improved by scanning with a faster CT tube rotation speed. PMID:25470359

  20. Assessing recognition memory using confidence ratings and response times

    PubMed Central

    Kahana, Michael J.

    2016-01-01

    Classification of stimuli into categories (such as ‘old’ and ‘new’ in tests of recognition memory or ‘present’ versus ‘absent’ in signal detection tasks) requires the mapping of internal signals to discrete responses. Introspective judgements about a given choice response are regularly employed in research, legal and clinical settings in an effort to measure the signal that is thought to be the basis of the classification decision. Correlations between introspective judgements and task performance suggest that such ratings often do convey information about internal states that are relevant for a given task, but well-known limitations of introspection call the fidelity of this information into question. We investigated to what extent response times can reveal information usually assessed with explicit confidence ratings. We quantitatively compared response times to confidence ratings in their ability to qualify recognition memory decisions and found convergent results suggesting that much of the information from confidence ratings can be obtained from response times. PMID:27152209

  1. The theoretical accuracy of Runge-Kutta time discretizations for the initial boundary value problem: A careful study of the boundary error

    NASA Technical Reports Server (NTRS)

    Carpenter, Mark H.; Gottlieb, David; Abarbanel, Saul; Don, Wai-Sun

    1993-01-01

    The conventional method of imposing time dependent boundary conditions for Runge-Kutta (RK) time advancement reduces the formal accuracy of the space-time method to first order locally, and second order globally, independently of the spatial operator. This counter intuitive result is analyzed in this paper. Two methods of eliminating this problem are proposed for the linear constant coefficient case: (1) impose the exact boundary condition only at the end of the complete RK cycle, (2) impose consistent intermediate boundary conditions derived from the physical boundary condition and its derivatives. The first method, while retaining the RK accuracy in all cases, results in a scheme with much reduced CFL condition, rendering the RK scheme less attractive. The second method retains the same allowable time step as the periodic problem. However it is a general remedy only for the linear case. For non-linear hyperbolic equations the second method is effective only for for RK schemes of third order accuracy or less. Numerical studies are presented to verify the efficacy of each approach.

  2. Malignant glioma - timing of response to radiation therapy

    SciTech Connect

    Gaspar, L.E.; Fisher, B.J.; MacDonald, D.R.; Cairncross, J.G. London Regional Cancer Centre, Ontario ); LeBer, D.V. ); Halperin, E.C.; Schold, S.C. Jr. )

    1993-04-02

    The response of malignant gliomas to radiation was examined retrospectively in 71 patients with newly diagnosed supratentorial malignant gliomas. Questions asked included frequency, timing and clinical significance of response. After surgery, all were treated with whole brain plus boost radiotherapy followed 8 weeks later by chemotherapy. The rate, degree, and timing of response to radiation were determined by comparing postoperative, end of radiation, and prechemotherapy CT scans on each patient. Postoperative residual tumor was evident on 63/71 postoperative scans. Twenty-two of 63 tumors (35%) had a partial or complete response to radiation. Twenty (32%) had responded by the end of radiation; 17 maximally. Six to 8 weeks later, three responding tumors had responded further and two previously stable ones had begun to respond. Only three tumors (5%) responded completely. A greater proportion of anaplastic gliomas than glioblastomas responded to radiation (52% vs. 26%). Protracted or delayed responses were only observed in patients with anaplastic glioma. Patients who responded to radiation did not live significantly longer than non-responders. However, tumor progression prior to chemotherapy was associated with significantly shorter survival. This CT scan-based analysis demonstrates that malignant gliomas are only moderately radioresponsive tumors and also demonstrates that response to radiation, if it is going to occur, is usually evident by the end of treatment. 6 refs., 1 fig., 1 tab.

  3. Accuracy of Real-time Couch Tracking During 3-dimensional Conformal Radiation Therapy, Intensity Modulated Radiation Therapy, and Volumetric Modulated Arc Therapy for Prostate Cancer

    SciTech Connect

    Wilbert, Juergen; Baier, Kurt; Hermann, Christian; Flentje, Michael; Guckenberger, Matthias

    2013-01-01

    Purpose: To evaluate the accuracy of real-time couch tracking for prostate cancer. Methods and Materials: Intrafractional motion trajectories of 15 prostate cancer patients were the basis for this phantom study; prostate motion had been monitored with the Calypso System. An industrial robot moved a phantom along these trajectories, motion was detected via an infrared camera system, and the robotic HexaPOD couch was used for real-time counter-steering. Residual phantom motion during real-time tracking was measured with the infrared camera system. Film dosimetry was performed during delivery of 3-dimensional conformal radiation therapy (3D-CRT), step-and-shoot intensity modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT). Results: Motion of the prostate was largest in the anterior-posterior direction, with systematic ( N-Ary-Summation ) and random ({sigma}) errors of 2.3 mm and 2.9 mm, respectively; the prostate was outside a threshold of 5 mm (3D vector) for 25.0%{+-}19.8% of treatment time. Real-time tracking reduced prostate motion to N-Ary-Summation =0.01 mm and {sigma} = 0.55 mm in the anterior-posterior direction; the prostate remained within a 1-mm and 5-mm threshold for 93.9%{+-}4.6% and 99.7%{+-}0.4% of the time, respectively. Without real-time tracking, pass rates based on a {gamma} index of 2%/2 mm in film dosimetry ranged between 66% and 72% for 3D-CRT, IMRT, and VMAT, on average. Real-time tracking increased pass rates to minimum 98% on average for 3D-CRT, IMRT, and VMAT. Conclusions: Real-time couch tracking resulted in submillimeter accuracy for prostate cancer, which transferred into high dosimetric accuracy independently of whether 3D-CRT, IMRT, or VMAT was used.

  4. Linear-scaling time-dependent density-functional theory beyond the Tamm-Dancoff approximation: Obtaining efficiency and accuracy with in situ optimised local orbitals

    SciTech Connect

    Zuehlsdorff, T. J. Payne, M. C.; Hine, N. D. M.; Haynes, P. D.

    2015-11-28

    We present a solution of the full time-dependent density-functional theory (TDDFT) eigenvalue equation in the linear response formalism exhibiting a linear-scaling computational complexity with system size, without relying on the simplifying Tamm-Dancoff approximation (TDA). The implementation relies on representing the occupied and unoccupied subspaces with two different sets of in situ optimised localised functions, yielding a very compact and efficient representation of the transition density matrix of the excitation with the accuracy associated with a systematic basis set. The TDDFT eigenvalue equation is solved using a preconditioned conjugate gradient algorithm that is very memory-efficient. The algorithm is validated on a small test molecule and a good agreement with results obtained from standard quantum chemistry packages is found, with the preconditioner yielding a significant improvement in convergence rates. The method developed in this work is then used to reproduce experimental results of the absorption spectrum of bacteriochlorophyll in an organic solvent, where it is demonstrated that the TDA fails to reproduce the main features of the low energy spectrum, while the full TDDFT equation yields results in good qualitative agreement with experimental data. Furthermore, the need for explicitly including parts of the solvent into the TDDFT calculations is highlighted, making the treatment of large system sizes necessary that are well within reach of the capabilities of the algorithm introduced here. Finally, the linear-scaling properties of the algorithm are demonstrated by computing the lowest excitation energy of bacteriochlorophyll in solution. The largest systems considered in this work are of the same order of magnitude as a variety of widely studied pigment-protein complexes, opening up the possibility of studying their properties without having to resort to any semiclassical approximations to parts of the protein environment.

  5. Linear-scaling time-dependent density-functional theory beyond the Tamm-Dancoff approximation: Obtaining efficiency and accuracy with in situ optimised local orbitals

    NASA Astrophysics Data System (ADS)

    Zuehlsdorff, T. J.; Hine, N. D. M.; Payne, M. C.; Haynes, P. D.

    2015-11-01

    We present a solution of the full time-dependent density-functional theory (TDDFT) eigenvalue equation in the linear response formalism exhibiting a linear-scaling computational complexity with system size, without relying on the simplifying Tamm-Dancoff approximation (TDA). The implementation relies on representing the occupied and unoccupied subspaces with two different sets of in situ optimised localised functions, yielding a very compact and efficient representation of the transition density matrix of the excitation with the accuracy associated with a systematic basis set. The TDDFT eigenvalue equation is solved using a preconditioned conjugate gradient algorithm that is very memory-efficient. The algorithm is validated on a small test molecule and a good agreement with results obtained from standard quantum chemistry packages is found, with the preconditioner yielding a significant improvement in convergence rates. The method developed in this work is then used to reproduce experimental results of the absorption spectrum of bacteriochlorophyll in an organic solvent, where it is demonstrated that the TDA fails to reproduce the main features of the low energy spectrum, while the full TDDFT equation yields results in good qualitative agreement with experimental data. Furthermore, the need for explicitly including parts of the solvent into the TDDFT calculations is highlighted, making the treatment of large system sizes necessary that are well within reach of the capabilities of the algorithm introduced here. Finally, the linear-scaling properties of the algorithm are demonstrated by computing the lowest excitation energy of bacteriochlorophyll in solution. The largest systems considered in this work are of the same order of magnitude as a variety of widely studied pigment-protein complexes, opening up the possibility of studying their properties without having to resort to any semiclassical approximations to parts of the protein environment.

  6. Linear-scaling time-dependent density-functional theory beyond the Tamm-Dancoff approximation: Obtaining efficiency and accuracy with in situ optimised local orbitals.

    PubMed

    Zuehlsdorff, T J; Hine, N D M; Payne, M C; Haynes, P D

    2015-11-28

    We present a solution of the full time-dependent density-functional theory (TDDFT) eigenvalue equation in the linear response formalism exhibiting a linear-scaling computational complexity with system size, without relying on the simplifying Tamm-Dancoff approximation (TDA). The implementation relies on representing the occupied and unoccupied subspaces with two different sets of in situ optimised localised functions, yielding a very compact and efficient representation of the transition density matrix of the excitation with the accuracy associated with a systematic basis set. The TDDFT eigenvalue equation is solved using a preconditioned conjugate gradient algorithm that is very memory-efficient. The algorithm is validated on a small test molecule and a good agreement with results obtained from standard quantum chemistry packages is found, with the preconditioner yielding a significant improvement in convergence rates. The method developed in this work is then used to reproduce experimental results of the absorption spectrum of bacteriochlorophyll in an organic solvent, where it is demonstrated that the TDA fails to reproduce the main features of the low energy spectrum, while the full TDDFT equation yields results in good qualitative agreement with experimental data. Furthermore, the need for explicitly including parts of the solvent into the TDDFT calculations is highlighted, making the treatment of large system sizes necessary that are well within reach of the capabilities of the algorithm introduced here. Finally, the linear-scaling properties of the algorithm are demonstrated by computing the lowest excitation energy of bacteriochlorophyll in solution. The largest systems considered in this work are of the same order of magnitude as a variety of widely studied pigment-protein complexes, opening up the possibility of studying their properties without having to resort to any semiclassical approximations to parts of the protein environment. PMID:26627950

  7. Time-domain response of the ARIANNA detector

    NASA Astrophysics Data System (ADS)

    Barwick, S. W.; Berg, E. C.; Besson, D. Z.; Duffin, T.; Hanson, J. C.; Klein, S. R.; Kleinfelder, S. A.; Piasecki, M.; Ratzlaff, K.; Reed, C.; Roumi, M.; Stezelberger, T.; Tatar, J.; Walker, J.; Young, R.; Zou, L.

    2015-03-01

    The Antarctic Ross Ice Shelf Antenna Neutrino Array (ARIANNA) is a high-energy neutrino detector designed to record the Askaryan electric field signature of cosmogenic neutrino interactions in ice. To understand the inherent radio-frequency (RF) neutrino signature, the time-domain response of the ARIANNA RF receiver must be measured. ARIANNA uses Create CLP5130-2N log-periodic dipole arrays (LPDAs). The associated effective height operator converts incident electric fields to voltage waveforms at the LDPA terminals. The effective height versus time and incident angle was measured, along with the associated response of the ARIANNA RF amplifier. The results are verified by correlating to field measurements in air and ice, using oscilloscopes. Finally, theoretical models for the Askaryan electric field are combined with the detector response to predict the neutrino signature.

  8. Disaster Response Networks in Uncertain Times: Practical Recommendations.

    ERIC Educational Resources Information Center

    Heaps, Richard A.

    This paper outlines the preparations necessary for state psychological associations to make a timely, well-coordinated, and successful mental health response to disaster or trauma. It is suggested that early planning, recruiting, training, connecting with an authorized disaster organization, forming a mental health coalition, organizing…

  9. 45 CFR 612.5 - Timing of responses to requests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Timing of responses to requests. 612.5 Section 612.5 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION... physical safety of an individual; or (B) An urgency to inform the public about an actual or alleged...

  10. Modeling Information Accumulation in Psychological Tests Using Item Response Times

    ERIC Educational Resources Information Center

    Ranger, Jochen; Kuhn, Jörg-Tobias

    2015-01-01

    In this article, a latent trait model is proposed for the response times in psychological tests. The latent trait model is based on the linear transformation model and subsumes popular models from survival analysis, like the proportional hazards model and the proportional odds model. Core of the model is the assumption that an unspecified monotone…

  11. Distinct Response Time Distributions in Attention Deficit Hyperactivity Disorder Subtypes

    ERIC Educational Resources Information Center

    Querne, Laurent; Berquin, Patrick

    2009-01-01

    Objective: To address the issue of response time (RT) profiles in hyperactive-impulsive (ADHD-HI), inattentive (ADHD-IA), and combined (ADHD-C) subtypes of ADHD. We hypothesized that children with ADHD-HI should respond more rapidly than children without ADHD and children with ADHD-IA and ADHD-C should respond more slowly than children without…

  12. Response Time in 14-Year-Olds with Language Impairment

    ERIC Educational Resources Information Center

    Miller, Carol A.; Leonard, Laurence B.; Kail, Robert V.; Zhang, Xuyang; Tomblin, J. Bruce; Francis, David J.

    2006-01-01

    Purpose: To determine whether children with language impairment were slower than typically developing peers at age 14, and whether slowing, if present, was similar across task domains; whether differences in response time (RT) across domains were the same for children with specific language impairment (SLI) and nonspecific language impairment…

  13. 38 CFR 1.556 - Timing of responses to requests.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false Timing of responses to requests. 1.556 Section 1.556 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS GENERAL PROVISIONS Procedures for Disclosure of Records Under the Freedom of Information Act §...

  14. 1 CFR 304.5 - Timing of responses to requests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 1 General Provisions 1 2012-01-01 2012-01-01 false Timing of responses to requests. 304.5 Section... telephone, e-mail or letter, whichever is most efficient, in each case. (c) Unusual circumstances. (1) Where.... (1) Requests and appeals will be taken out of order and given expedited treatment whenever it...

  15. 38 CFR 1.556 - Timing of responses to requests.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false Timing of responses to requests. 1.556 Section 1.556 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS GENERAL PROVISIONS Procedures for Disclosure of Records Under the Freedom of Information Act §...

  16. 48 CFR 1505.203 - Publicizing and response time.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Publicizing and response time. 1505.203 Section 1505.203 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY ACQUISITION PLANNING PUBLICIZING CONTRACT ACTIONS Synopses of Proposed Contract Actions 1505.203...

  17. 48 CFR 1505.203 - Publicizing and response time.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Publicizing and response time. 1505.203 Section 1505.203 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY ACQUISITION PLANNING PUBLICIZING CONTRACT ACTIONS Synopses of Proposed Contract Actions 1505.203...

  18. 48 CFR 1505.203 - Publicizing and response time.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Publicizing and response time. 1505.203 Section 1505.203 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY ACQUISITION PLANNING PUBLICIZING CONTRACT ACTIONS Synopses of Proposed Contract Actions 1505.203...

  19. 40 CFR 1066.245 - Response time verification.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... automated process to verify response time. You may perform this test either at two different inertia... base inertia and two acceleration rates that cover the range of acceleration rates experienced during... less than 100 milliseconds for each inertia setting. ER28AP14.066...

  20. From Zero to Sixty: Calibrating Real-Time Responses

    ERIC Educational Resources Information Center

    Koulis, Theodoro; Ramsay, James O.; Levitin, Daniel J.

    2008-01-01

    Recent advances in data recording technology have given researchers new ways of collecting on-line and continuous data for analyzing input-output systems. For example, continuous response digital interfaces are increasingly used in psychophysics. The statistical problem related to these input-output systems reduces to linking time-varying…

  1. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  2. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  3. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  4. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  5. 40 CFR 89.316 - Analyzer leakage and response time.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Equipment Provisions § 89.316 Analyzer leakage and response time. (a) Vacuum side leak check. (1) Any location within the analysis system where a vacuum leak could affect the test results must be checked. (2) The maximum allowable leakage rate on the vacuum side is 0.5 percent of the in-use flow rate for...

  6. Processing Time Shifts Affects the Execution of Motor Responses

    ERIC Educational Resources Information Center

    Sell, Andrea J.; Kaschak, Michael P.

    2011-01-01

    We explore whether time shifts in text comprehension are represented spatially. Participants read sentences involving past or future events and made sensibility judgment responses in one of two ways: (1) moving toward or away from their body and (2) pressing the toward or away buttons without moving. Previous work suggests that spatial…

  7. Vectorised simulation of the response of a time projection chamber

    NASA Astrophysics Data System (ADS)

    Georgiopoulos, C. H.; Mermikides, M. E.

    1989-12-01

    A Monte Carlo code used for the detailed simulation of the response of the ALEPH time projection chamber has been successfully restructured to exploit the vector architectures of the CDC CYBER-205, ETA10 and CRAY X-MP supercomputers. Some aspects of the vector implementation are discussed and the performance on the various processors is compared.

  8. Separability of Item and Person Parameters in Response Time Models.

    ERIC Educational Resources Information Center

    Van Breukelen, Gerard J. P.

    1997-01-01

    Discusses two forms of separability of item and person parameters in the context of response time models. The first is "separate sufficiency," and the second is "ranking independence." For each form a theorem stating sufficient conditions is proved. The two forms are shown to include several cases of models from psychometric and biometric…

  9. Timing and Causality in the Generation of Learned Eyelid Responses

    PubMed Central

    Sánchez-Campusano, Raudel; Gruart, Agnès; Delgado-García, José M.

    2011-01-01

    The cerebellum-red nucleus-facial motoneuron (Mn) pathway has been reported as being involved in the proper timing of classically conditioned eyelid responses. This special type of associative learning serves as a model of event timing for studying the role of the cerebellum in dynamic motor control. Here, we have re-analyzed the firing activities of cerebellar posterior interpositus (IP) neurons and orbicularis oculi (OO) Mns in alert behaving cats during classical eyeblink conditioning, using a delay paradigm. The aim was to revisit the hypothesis that the IP neurons (IPns) can be considered a neuronal phase-modulating device supporting OO Mns firing with an emergent timing mechanism and an explicit correlation code during learned eyelid movements. Optimized experimental and computational tools allowed us to determine the different causal relationships (temporal order and correlation code) during and between trials. These intra- and inter-trial timing strategies expanding from sub-second range (millisecond timing) to longer-lasting ranges (interval timing) expanded the functional domain of cerebellar timing beyond motor control. Interestingly, the results supported the above-mentioned hypothesis. The causal inferences were influenced by the precise motor and pre-motor spike timing in the cause-effect interval, and, in addition, the timing of the learned responses depended on cerebellar–Mn network causality. Furthermore, the timing of CRs depended upon the probability of simulated causal conditions in the cause-effect interval and not the mere duration of the inter-stimulus interval. In this work, the close relation between timing and causality was verified. It could thus be concluded that the firing activities of IPns may be related more to the proper performance of ongoing CRs (i.e., the proper timing as a consequence of the pertinent causality) than to their generation and/or initiation. PMID:21941469

  10. Aircraft Fault Detection Using Real-Time Frequency Response Estimation

    NASA Technical Reports Server (NTRS)

    Grauer, Jared A.

    2016-01-01

    A real-time method for estimating time-varying aircraft frequency responses from input and output measurements was demonstrated. The Bat-4 subscale airplane was used with NASA Langley Research Center's AirSTAR unmanned aerial flight test facility to conduct flight tests and collect data for dynamic modeling. Orthogonal phase-optimized multisine inputs, summed with pilot stick and pedal inputs, were used to excite the responses. The aircraft was tested in its normal configuration and with emulated failures, which included a stuck left ruddervator and an increased command path latency. No prior knowledge of a dynamic model was used or available for the estimation. The longitudinal short period dynamics were investigated in this work. Time-varying frequency responses and stability margins were tracked well using a 20 second sliding window of data, as compared to a post-flight analysis using output error parameter estimation and a low-order equivalent system model. This method could be used in a real-time fault detection system, or for other applications of dynamic modeling such as real-time verification of stability margins during envelope expansion tests.

  11. X-ray streak camera cathode development and timing accuracy of the 4{omega} ultraviolet fiducial system at the National Ignition Facility

    SciTech Connect

    Opachich, Y. P.; Palmer, N.; Homoelle, D.; Hatch, B.; Bell, P.; Bradley, D.; Kalantar, D.; Browning, D.; Landen, O.; Zuegel, J.

    2012-10-15

    The convergent ablator experiments at the National Ignition Facility (NIF) are designed to measure the peak velocity and remaining ablator mass of an indirectly driven imploding capsule. Such a measurement can be performed using an x-ray source to backlight the capsule and an x-ray streak camera to record the capsule as it implodes. The ultimate goal of this experiment is to achieve an accuracy of 2% in the velocity measurement, which translates to a {+-}2 ps temporal accuracy over any 300 ps interval for the streak camera. In order to achieve this, a 4{omega} (263 nm) temporal fiducial system has been implemented for the x-ray streak camera at NIF. Aluminum, titanium, gold, and silver photocathode materials have been tested. Aluminum showed the highest relative quantum efficiency, with five times more peak signal counts per fiducial pulse when compared to Gold. The fiducial pulse data were analyzed to determine the centroiding statistical accuracy for incident laser pulse energies of 1 and 10 nJ, showing an accuracy of {+-}1.6 ps and {+-}0.7 ps, respectively.

  12. X-ray Streak Camera Cathode Development and Timing Accuracy of the 4w UV Fiducial System at the National Ignition Facility

    SciTech Connect

    Opachich, Y P; Palmer, N; Homoelle, D; Hatch, B W; Bell, P; Bradley, D; Kalantar, D; Browning, D; Landen, O

    2012-05-02

    The convergent ablator experiments at the National Ignition Facility (NIF) are designed to measure the peak velocity and remaining ablator mass of an indirectly driven imploding capsule. Such a measurement can be performed using an x-ray source to backlight the capsule and an x-ray streak camera to record the capsule as it implodes. The ultimate goal of this experiment is to achieve an accuracy of 2% in the velocity measurement, which translates to a {+-}2 ps temporal accuracy over any 300 ps interval for the streak camera. In order to achieve this, a 4-{omega} (263nm) temporal fiducial system has been implemented for the x-ray streak camera at NIF. Aluminum, Titanium, Gold and Silver photocathode materials have been tested. Aluminum showed the highest quantum efficiency, with five times more peak signal counts per fiducial pulse when compared to Gold. The fiducial pulse data was analyzed to determine the centroiding a statistical accuracy for incident laser pulse energies of 1 and 10 nJ, showing an accuracy of {+-}1.6 ps and {+-}0.7 ps respectively.

  13. X-ray streak camera cathode development and timing accuracy of the 4ω ultraviolet fiducial system at the National Ignition Facilitya)

    NASA Astrophysics Data System (ADS)

    Opachich, Y. P.; Palmer, N.; Homoelle, D.; Hatch, B.; Bell, P.; Bradley, D.; Kalantar, D.; Browning, D.; Zuegel, J.; Landen, O.

    2012-10-01

    The convergent ablator experiments at the National Ignition Facility (NIF) are designed to measure the peak velocity and remaining ablator mass of an indirectly driven imploding capsule. Such a measurement can be performed using an x-ray source to backlight the capsule and an x-ray streak camera to record the capsule as it implodes. The ultimate goal of this experiment is to achieve an accuracy of 2% in the velocity measurement, which translates to a ±2 ps temporal accuracy over any 300 ps interval for the streak camera. In order to achieve this, a 4ω (263 nm) temporal fiducial system has been implemented for the x-ray streak camera at NIF. Aluminum, titanium, gold, and silver photocathode materials have been tested. Aluminum showed the highest relative quantum efficiency, with five times more peak signal counts per fiducial pulse when compared to Gold. The fiducial pulse data were analyzed to determine the centroiding statistical accuracy for incident laser pulse energies of 1 and 10 nJ, showing an accuracy of ±1.6 ps and ±0.7 ps, respectively.

  14. Adaptive Responses to Prochloraz Exposure That Alter Dose-Response and Time-Course Behaviors

    EPA Science Inventory

    Dose response and time-course (DRTC) are, along with exposure, the major determinants of health risk. Adaptive changes within exposed organisms in response to environmental stress are common, and alter DRTC behaviors to minimize the effects caused by stressors. In this project, ...

  15. Statistical Tests of Conditional Independence between Responses and/or Response Times on Test Items

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Glas, Cees A. W.

    2010-01-01

    Three plausible assumptions of conditional independence in a hierarchical model for responses and response times on test items are identified. For each of the assumptions, a Lagrange multiplier test of the null hypothesis of conditional independence against a parametric alternative is derived. The tests have closed-form statistics that are easy to…

  16. The Time Course Effect of Moderate Intensity Exercise on Response Execution and Response Inhibition

    ERIC Educational Resources Information Center

    Joyce, Jennifer; Graydon, Jan; McMorris, Terry; Davranche, Karen

    2009-01-01

    This research aimed to investigate the time course effect of a moderate steady-state exercise session on response execution and response inhibition using a stop-task paradigm. Ten participants performed a stop-signal task whilst cycling at a carefully controlled workload intensity (40% of maximal aerobic power), immediately following exercise and…

  17. Effects of cognitive load and prosthetic liner on volitional response times to vibrotactile feedback.

    PubMed

    Sharma, Aman; Leineweber, Matthew J; Andrysek, Jan

    2016-01-01

    Artificial tactile feedback systems can improve prosthetic function for people with amputation by substituting for lost proprioception in the missing limb. However, limited data exists to guide the design and application of these systems for mobility and balance scenarios. The purpose of this study was to evaluate the performance of a noninvasive artificial sensory feedback (ASF) system on lower-limb function in the presence of a cognitive load and a liner interface. Reaction times (RTs) and accuracy of leg-movement responses to vibratory stimuli at the thigh were recorded for 12 nondisabled individuals and 3 participants with transfemoral amputation using a custom-built testing apparatus. The results indicate that the addition of a cognitive load increases response times relative to the baseline condition by 0.26 to 0.33 s. The prosthetic liner produced a less pronounced increase in RT of 0.06 to 0.11 s. Participants were able to correctly identify the stimulus location with nearly 100% accuracy. These increased RTs are nontrivial and must be considered in designing ASF systems. PMID:27532493

  18. Predicting aquifer response time for application in catchment modeling.

    PubMed

    Walker, Glen R; Gilfedder, Mat; Dawes, Warrick R; Rassam, David W

    2015-01-01

    It is well established that changes in catchment land use can lead to significant impacts on water resources. Where land-use changes increase evapotranspiration there is a resultant decrease in groundwater recharge, which in turn decreases groundwater discharge to streams. The response time of changes in groundwater discharge to a change in recharge is a key aspect of predicting impacts of land-use change on catchment water yield. Predicting these impacts across the large catchments relevant to water resource planning can require the estimation of groundwater response times from hundreds of aquifers. At this scale, detailed site-specific measured data are often absent, and available spatial data are limited. While numerical models can be applied, there is little advantage if there are no detailed data to parameterize them. Simple analytical methods are useful in this situation, as they allow the variability in groundwater response to be incorporated into catchment hydrological models, with minimal modeling overhead. This paper describes an analytical model which has been developed to capture some of the features of real, sloping aquifer systems. The derived groundwater response timescale can be used to parameterize a groundwater discharge function, allowing groundwater response to be predicted in relation to different broad catchment characteristics at a level of complexity which matches the available data. The results from the analytical model are compared to published field data and numerical model results, and provide an approach with broad application to inform water resource planning in other large, data-scarce catchments. PMID:24842053

  19. Improving mass accuracy of high performance liquid chromatography/electrospray ionization time-of-flight mass spectrometry of intact antibodies.

    PubMed

    Gadgil, Himanshu S; Pipes, Gary D; Dillon, Thomas M; Treuheit, Michael J; Bondarenko, Pavel V

    2006-06-01

    The glycosylation profile of intact antibody due to the galactose and fucose heterogeneity in the N-linked sugars was determined with instrument resolution of 5000 and 10,000. After deconvolution of electrospray ionization mass spectra to complete convergence, several extra peaks appeared in addition to the peaks observed in the original mass spectra. The artificial peaks were avoided if deconvolution was stopped after a smaller number of iterations. A standard antibody was used as an external calibrant to minimize mass measurement errors during long-period experiments. Precision of four consecutive LC/MS measurements of the same antibody was 10 ppm (+/-1.5 Da). By using this approach, the masses of 11 intact antibodies were measured. All antibodies containing N-terminal glutamines had a negative mass shift due to the formation of pyroglutamate (-17 Da). Although the pyroglutamate variant of intact antibody was not resolved from the unmodified variant, this modification led to a mass shift proportional to the percentage of N-terminal pyroglutamate. By accurately measuring the mass shift we were able to quantify the abundance of pyroglutamic acid on intact antibodies. Mass accuracy in measuring different antibodies was below 30 ppm (+/-4 Da). The accurate mass measurement can be an effective tool for monitoring chemical degradations in therapeutic antibodies. PMID:16631376

  20. Time to smell: a cascade model of human olfactory perception based on response-time (RT) measurement

    PubMed Central

    Olofsson, Jonas K.

    2014-01-01

    The timing of olfactory behavioral decisions may provide an important source of information about how the human olfactory-perceptual system is organized. This review integrates results from olfactory response-time (RT) measurements from a perspective of mental chronometry. Based on these findings, a new cascade model of human olfaction is presented. Results show that main perceptual decisions are executed with high accuracy within about 1~s of sniff onset. The cascade model proposes the existence of distinct processing stages within this brief time-window. According to the cascade model, different perceptual features become accessible to the perceiver at different time-points, and the output of earlier processing stages provides the input for later processing stages. The olfactory cascade starts with detecting the odor, which is followed by establishing an odor object. The odor object, in turn, triggers systems for determining odor valence and edibility. Evidence for the cascade model comes from studies showing that RTs for odor valence and edibility assessment are predicted by the shorter RTs needed to establish the odor object. Challenges for future research include innovative task designs for olfactory RT experiments and the integration of the behavioral processing sequence into the underlying cortical processes using complementary RT measures and neuroimaging methods. PMID:24550861

  1. Monitoring Ambulation of Patients in Geriatric Rehabilitation Wards: The Accuracy of Clinicians' Prediction of Patients' Walking Time

    ERIC Educational Resources Information Center

    Cheung, Vivian H. Y.; Salih, Salih A.; Crouch, Alisa; Karunanithi, Mohanraj K.; Gray, Len

    2012-01-01

    The aim of this study is to determine whether clinicians' estimates of patients' walking time agree with those determined by accelerometer devices. The walking time was measured using a waist-mounted accelerometer device everyday during the patients' waking hours. At each weekly meeting, clinicians estimated the patients' average daily walking…

  2. Ampoule failure sensor time response testing: Experiments 2 and 3

    NASA Technical Reports Server (NTRS)

    Johnson, M. L.; Watring, D. A.

    1994-01-01

    The response time of an ampoule failure sensor exposed to a liquid or vapor gallium-arsenide (GaAs) and the corresponding breach time of the containing cartridge is investigated. The experiments were conducted in niobium-hafnium (WC-103) cartridges with an exterior silicide coating. These cartridges were built to flight specifications that were used in NASA's Crystal Growth Furnace during the first United States Microgravity Laboratory (USML-1) mission. The ampoule failure sensor is a chemical fuse made from a metal with which the semiconductor material reacts more rapidly than it does with the containing cartridge. In these experiments a platinum metal was used for the manufacture of the sensors. This technical report discusses the response time of two different sensor designs. The first design utilizes a helical wrapped wire and the second uses a single bare wire element. Experimental results indicate that both sensors are adequate in sensing the presence of molten or vapor GaAs with the latter having a 2-minute longer response time. In both experiments, the containing cartridge was breached within 185 minutes after ampoule rupture.

  3. Ultimate response time of high electron mobility transistors

    SciTech Connect

    Rudin, Sergey; Rupper, Greg; Shur, Michael

    2015-05-07

    We present theoretical studies of the response time of the two-dimensional gated electron gas to femtosecond pulses. Our hydrodynamic simulations show that the device response to a short pulse or a step-function signal is either smooth or oscillating time-decay at low and high mobility, μ, values, respectively. At small gate voltage swings, U{sub 0} = U{sub g} − U{sub th}, where U{sub g} is the gate voltage and U{sub th} is the threshold voltage, such that μU{sub 0}/L < v{sub s}, where L is the channel length and v{sub s} is the effective electron saturation velocity, the decay time in the low mobility samples is on the order of L{sup 2}/(μU{sub 0}), in agreement with the analytical drift model. However, the decay is preceded by a delay time on the order of L/s, where s is the plasma wave velocity. This delay is the ballistic transport signature in collision-dominated devices, which becomes important during very short time periods. In the high mobility devices, the period of the decaying oscillations is on the order of the plasma wave velocity transit time. Our analysis shows that short channel field effect transistors operating in the plasmonic regime can meet the requirements for applications as terahertz detectors, mixers, delay lines, and phase shifters in ultra high-speed wireless communication circuits.

  4. Effect of loudness on reaction time and response force in different motor tasks.

    PubMed

    Jaśkowski, Piotr; Włodarczyk, Dariusz

    2005-12-01

    Van der Molen and Keuss, in 1979 and 1981, showed that paradoxically long reaction times occur with extremely strong auditory stimuli when the task is difficult, e.g., choice-by-location or Simon paradigm. It was argued that this paradoxical behavior of RT is due to active inhibition of an arousal-dependent bypassing mechanism to prevent false responses. As the peak force, i.e., maximal force exerted by participants on a response key, is considered to be related to immediate arousal, we predicted that for extremely loud stimuli and for difficult tasks, lengthening of RT should be associated with reduction of peak force. Moreover, these effects should be enhanced when emphasis is on accuracy rather than speed. Although the relation between RT and intensity depended on task difficulty, no increase in RT was found for the loudest tones. Moreover, peak force increased monotonically with loudness, showing no tendency to be suppressed for loudest tones and difficult tasks. PMID:16491701

  5. Spatiotemporal neural integration for bistable perception in a response-time structure-from-motion task.

    PubMed

    Wang, Zhisong; Logothetis, Nikos K; Liang, Hualou

    2009-12-01

    The question of how perception arises from neuronal activity in the visual cortex is of fundamental importance to many issues in cognitive neuroscience. To address this question, we adopt a unique experimental paradigm in which bistable stimuli, namely structure from motion (SFM), are employed to dissociate the visual input from perception while monitoring cortical neural activity. In this paper, we analyze the dynamic responses of the multiunit activity, simultaneously collected from multiple channels in the middle temporal visual cortex of awake behaving macaque monkeys, for decoding the bistable percepts of SFM in a response-time (RT) perceptual discrimination task. Our goal is to understand how the perceptual discriminative information of neuronal population activity evolves and accumulates over time to mediate behaviors. Here, we used a discriminative classifier called the logistic regression and contrasted it with two generative classifiers, namely the quadratic discriminant analysis (QDA) and linear discriminant analysis (LDA), to achieve the spatiotemporal integration of neural activity and dynamically decode the perceptual reports on a single-trial basis. We found that the logistic regression outperforms both QDA and LDA in terms of decoding accuracy for both single-channel and multichannel decoding of bistable percepts. Subsequent analysis of the temporal profile of neural population decoding in relation to RT revealed that the amplitude and latency of the decoding accuracy are highly correlated with the RT, thus indicating that the monkeys respond faster when the decoding accuracy is higher and has shorter latency. These findings suggest that enhanced neuronal discrimination ability and shortened neuronal discrimination latency may impact monkeys' behaviors. PMID:19635689

  6. Response to varying amounts of time in reading intervention for students with low response to intervention.

    PubMed

    Wanzek, Jeanne; Vaughn, Sharon

    2008-01-01

    Two studies examined response to varying amounts of time in reading intervention for two cohorts of first-grade students demonstrating low levels of reading after previous intervention. Students were assigned to one of three groups that received (a) a single dose of intervention, (b) a double dose of intervention, or (c) no intervention. Examination of individual student response to intervention indicated that more students in the treatment groups demonstrated accelerated learning over time than students in the comparison condition. Students' responses to the single-dose and double-dose interventions were similar over time. Students in all conditions demonstrated particular difficulties with gains in reading fluency. Implications for future research and practice within response to intervention models are provided. PMID:18354933

  7. An Implicit Measure of Associations with Mental Illness versus Physical Illness: Response Latency Decomposition and Stimuli Differential Functioning in Relation to IAT Order of Associative Conditions and Accuracy

    PubMed Central

    Mannarini, Stefania; Boffo, Marilisa

    2014-01-01

    The present study aimed at the definition of a latent measurement dimension underlying an implicit measure of automatic associations between the concept of mental illness and the psychosocial and biogenetic causal explanatory attributes. To this end, an Implicit Association Test (IAT) assessing the association between the Mental Illness and Physical Illness target categories to the Psychological and Biologic attribute categories, representative of the causal explanation domains, was developed. The IAT presented 22 stimuli (words and pictures) to be categorized into the four categories. After 360 university students completed the IAT, a Many-Facet Rasch Measurement (MFRM) modelling approach was applied. The model specified a person latency parameter and a stimulus latency parameter. Two additional parameters were introduced to denote the order of presentation of the task associative conditions and the general response accuracy. Beyond the overall definition of the latent measurement dimension, the MFRM was also applied to disentangle the effect of the task block order and the general response accuracy on the stimuli response latency. Further, the MFRM allowed detecting any differential functioning of each stimulus in relation to both block ordering and accuracy. The results evidenced: a) the existence of a latency measurement dimension underlying the Mental Illness versus Physical Illness - Implicit Association Test; b) significant effects of block order and accuracy on the overall latency; c) a differential functioning of specific stimuli. The results of the present study can contribute to a better understanding of the functioning of an implicit measure of semantic associations with mental illness and give a first blueprint for the examination of relevant issues in the development of an IAT. PMID:25000406

  8. Planck 2013 results. VII. HFI time response and beams

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J. J.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Bowyer, J. W.; Bridges, M.; Bucher, M.; Burigana, C.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chary, R.-R.; Chiang, H. C.; Chiang, L.-Y.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Dunkley, J.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Eriksen, H. K.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Haissinski, J.; Hansen, F. K.; Hanson, D.; Harrison, D.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hou, Z.; Hovest, W.; Huffenberger, K. M.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lasenby, A.; Laureijs, R. J.; Lawrence, C. R.; Leonardi, R.; Leroy, C.; Lesgourgues, J.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; MacTavish, C. J.; Maffei, B.; Mandolesi, N.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matsumura, T.; Matthai, F.; Mazzotta, P.; McGehee, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polegre, A. M.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rowan-Robinson, M.; Rusholme, B.; Sandri, M.; Santos, D.; Sauvé, A.; Savini, G.; Scott, D.; Shellard, E. P. S.; Spencer, L. D.; Starck, J.-L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sureau, F.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Tavagnacco, D.; Terenzi, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-11-01

    This paper characterizes the effective beams, the effective beam window functions and the associated errors for the Planck High Frequency Instrument (HFI) detectors. The effective beam is theangular response including the effect of the optics, detectors, data processing and the scan strategy. The window function is the representation of this beam in the harmonic domain which is required to recover an unbiased measurement of the cosmic microwave background angular power spectrum. The HFI is a scanning instrument and its effective beams are the convolution of: a) the optical response of the telescope and feeds; b) the processing of the time-ordered data and deconvolution of the bolometric and electronic transfer function; and c) the merging of several surveys to produce maps. The time response transfer functions are measured using observations of Jupiter and Saturn and by minimizing survey difference residuals. The scanning beam is the post-deconvolution angular response of the instrument, and is characterized with observations of Mars. The main beam solid angles are determined to better than 0.5% at each HFI frequency band. Observations of Jupiter and Saturn limit near sidelobes (within 5°) to about 0.1% of the total solid angle. Time response residuals remain as long tails in the scanning beams, but contribute less than 0.1% of the total solid angle. The bias and uncertainty in the beam products are estimated using ensembles of simulated planet observations that include the impact of instrumental noise and known systematic effects. The correlation structure of these ensembles is well-described by five error eigenmodes that are sub-dominant to sample variance and instrumental noise in the harmonic domain. A suite of consistency tests provide confidence that the error model represents a sufficient description of the data. The total error in the effective beam window functions is below 1% at 100 GHz up to multipole ℓ ~ 1500, and below 0.5% at 143 and 217 GHz up to

  9. Time-dependent response of filamentary composite spherical pressure vessels

    NASA Technical Reports Server (NTRS)

    Dozier, J. D.

    1983-01-01

    A filamentary composite spherical pressure vessel is modeled as a pseudoisotropic (or transversely isotropic) composite shell, with the effects of the liner and fill tubes omitted. Equations of elasticity, macromechanical and micromechanical formulations, and laminate properties are derived for the application of an internally pressured spherical composite vessel. Viscoelastic properties for the composite matrix are used to characterize time-dependent behavior. Using the maximum strain theory of failure, burst pressure and critical strain equations are formulated, solved in the Laplace domain with an associated elastic solution, and inverted back into the time domain using the method of collocation. Viscoelastic properties of HBFR-55 resin are experimentally determined and a Kevlar/HBFR-55 system is evaluated with a FORTRAN program. The computed reduction in burst pressure with respect to time indicates that the analysis employed may be used to predict the time-dependent response of a filamentary composite spherical pressure vessel.

  10. Response time of large-scale electrochromic devices

    SciTech Connect

    Randin, J.P.

    1990-12-31

    The studies related to electrochromic phenomena performed in the seventies were mainly aimed at the development of information displays. Such applications require small electrode sizes, i.e. with active surface areas of between about 0.01 to 10 cm{sup 2}. The development of large information devices and chiefly smart windows require much larger switching areas. This paper deals with the influence of increasing the active surface area on the response time. The latter depends on both properties of the cell components (transparent conducting layer, electrochromic film, electrolyte and counter electrode) and structure of the cell (size, shape, gap, resistivity of the busbar). Experimental devices were constructed with given components and cell geometry. The effect of a series resistance arisen mainly from the cell size was investigated and explained by the effect of the additional series resistance on the response time of a diffusion-controlled process. The study indicates that the scaling-up of WO{sub 3} devices will be limited by an increase of the response time with increasing active area.

  11. High frequency dielectrophoretic response of microalgae over time

    PubMed Central

    Hadady, Hanieh; Wong, Johnson J.; Hiibel, Sage R.; Redelman, Doug; Geiger, Emil J.

    2015-01-01

    The high frequency dielectrophoresis (>20 MHz) response of microalgae cells with different lipid content was monitored over time. Chlamydomonas reinhardtii was cultured in regular medium and under nitrogen-depleted conditions in order to produce populations of cells with low and high lipid content, respectively. The electrical conductivity (EC) of the culture media was also monitored over the same time. The upper crossover frequency (UCOF) decreased for high-lipid cells over time. The single-shell model predicts that the upper crossover frequency is dictated primarily by the dielectric properties of the cytoplasm. The high frequency DEP response of the high-lipid cells’ cytoplasm was changed by lipid accumulation. DEP response of the low-lipid cells also varied with the conductivity of the culture media due to nutrient consumption. Relative lipid content was estimated with BODIPY 505/515 dye by calculating the area-weighted intensity average of fluorescent images. Finally, microalgae cells were successfully separated based on lipid content at 41 MHz and DEP media conductivity 106 ± 1 µS/cm. PMID:25229637

  12. Fundamental earth orientation parameters in determining the accuracy of the long-term ephemeris-time corrections in satellite navigation

    NASA Astrophysics Data System (ADS)

    Markov, Yu. G.; Perepelkin, V. V.; Chazov, V. V.; Shemyakov, A. O.

    2015-12-01

    A few-parameter numerical-analytical model for the rotational-oscillatory motions of the Earth is used on long time intervals in the processing of the highly accurate measurements of the topocentric distances to the Etalon-1 and Etalon-2 artificial Earth satellites. A proposed model can be used in satellite navigation algorithms.

  13. Real-time performance modelling of a Sustained Attention to Response Task.

    PubMed

    Larue, Grégoire S; Rakotonirainy, Andry; Pettitt, Anthony N

    2010-10-01

    Vigilance declines when exposed to highly predictable and uneventful tasks. Monotonous tasks provide little cognitive and motor stimulation and contribute to human errors. This paper aims to model and detect vigilance decline in real time through participants' reaction times during a monotonous task. A laboratory-based experiment adapting the Sustained Attention to Response Task (SART) is conducted to quantify the effect of monotony on overall performance. Relevant parameters are then used to build a model detecting hypovigilance throughout the experiment. The accuracy of different mathematical models is compared to detect in real time - minute by minute - the lapses in vigilance during the task. It is shown that monotonous tasks can lead to an average decline in performance of 45%. Furthermore, vigilance modelling enables the detection of vigilance decline through reaction times with an accuracy of 72% and a 29% false alarm rate. Bayesian models are identified as a better model to detect lapses in vigilance as compared with neural networks and generalised linear mixed models. This modelling could be used as a framework to detect vigilance decline of any human performing monotonous tasks. STATEMENT OF RELEVANCE: Existing research on monotony is largely entangled with endogenous factors such as sleep deprivation, fatigue and circadian rhythm. This paper uses a Bayesian model to assess the effects of a monotonous task on vigilance in real time. It is shown that the negative effects of monotony on the ability to sustain attention can be mathematically modelled and predicted in real time using surrogate measures, such as reaction times. This allows the modelling of vigilance fluctuations. PMID:20865604

  14. Influence of the Helicopter Time Domain Electromagnetic System Off-Time Response by the Transmitter Assembly

    NASA Astrophysics Data System (ADS)

    Vetrov, A.; Mejzr, I.

    2010-12-01

    While developing a new Helicopter Time Domain Electromagnetic system (P-THEM), Pico Envirotec Inc (PEI) has studied the effect of the transmitter assembly on the acquired data. The P-THEM system consists of a loop-transmitter assembly, powered by a motor generator, 3-axis coil receiver attached at the midpoint of a tow cable and an additional Z-axis (dB/dt) receiver installed on the rear section of the transmitter loop. The system is towed by a helicopter on a 230 foot long tow cable. The transmitter loop is designed to produce a peak magnetic moment of approximately 250,000 NIA with a base frequency of 30 Hz (adjustable to 25Hz) and a quarter length duty cycle (4 ms on-time). The secondary field acquired with a dB/dt receiver coil consists of a ground response and a system response: SF=Rg+Rsys, where SF - the secondary field, Rg - ground response, Rsys - system response. The system itself, especially the transmitter assembly, being a conductor in an induced magnetic field, creates a magnetic anomaly. The influence of the transmitter assembly anomaly on the received signal depends on the position of the receiver coil against the transmitter, the intensity of on-time pulse and transmitter electro-magnetic properties. At the same time, the ground response acquired with a receiver coil depends on the length and the moment of transmitter pulse, as well as the position and distance of the receiver coil from the ground. This can be for vertical field (Z) receiver coil described as RXz(t)=e(t)pz(t)Rgz(t)+d(t)k(t)j(t)TXz(t), where RXz(t) - receiver response, e(t) - elevation of the receiver over the ground, pz(t) - horizontal projection of the receiver coil, Rgz(t) - vertical component of ground response, d(t) - distance (elevation) between the receiver coil and the transmitter loop, k(t) - the position of the receiver in the transmitter field, j(t) - the transmitter assembly electromagnetic properties, TXz(t) -transmitter field (Primary field on-time, and transmitter

  15. Real-time Pricing Demand Response in Operations

    SciTech Connect

    Widergren, Steven E.; Marinovici, Maria C.; Berliner, Teri; Graves, Alan

    2012-07-26

    Abstract—Dynamic pricing schemes have been implemented in commercial and industrial application settings, and recently they are getting attention for application to residential customers. Time-of-use and critical-peak-pricing rates are in place in various regions and are being piloted in many more. These programs are proving themselves useful for balancing energy during peak periods; however, real-time (5 minute) pricing signals combined with automation in end-use systems have the potential to deliver even more benefits to operators and consumers. Besides system peak shaving, a real-time pricing system can contribute demand response based on the locational marginal price of electricity, reduce load in response to a generator outage, and respond to local distribution system capacity limiting situations. The US Department of Energy (DOE) is teaming with a mid-west electricity service provider to run a distribution feeder-based retail electricity market that negotiates with residential automation equipment and clears every 5 minutes, thus providing a signal for lowering or raising electric consumption based on operational objectives of economic efficiency and reliability. This paper outlines the capability of the real-time pricing system and the operational scenarios being tested as the system is rolled-out starting in the first half of 2012.

  16. The Screening Accuracy of the Parent and Teacher-Reported Social Responsiveness Scale (SRS): Comparison with the 3Di and ADOS.

    PubMed

    Duvekot, Jorieke; van der Ende, Jan; Verhulst, Frank C; Greaves-Lord, Kirstin

    2015-06-01

    The screening accuracy of the parent and teacher-reported Social Responsiveness Scale (SRS) was compared with an autism spectrum disorder (ASD) classification according to (1) the Developmental, Dimensional, and Diagnostic Interview (3 Di), (2) the Autism Diagnostic Observation Schedule (ADOS), (3) both the 3 Di and ADOS, in 186 children referred to six mental health centers. The parent report showed excellent correspondence to an ASD classification according to the 3 Di and both the 3 Di and ADOS. The teacher report added significantly to the screening accuracy over and above the parent report when compared with the ADOS classification. Findings support the screening utility of the parent-reported SRS among clinically referred children and indicate that different informants may provide unique information relevant for ASD assessment. PMID:25428292

  17. Sensitivity and response time improvements in millimeter-wave spectrometers

    SciTech Connect

    Kolbe, W.F.; Leskovar, B.

    1980-09-01

    A new version of a microwave spectrometer for the detection of gaseous pollutants and other atmospheric constituents is described. The spectrometer, which operates in the vicinity of 70 GHz, employs a Fabry-Perot resonator as a sample cell and uses superhetrodyne detection for high sensitivity. The spectrometer has been modified to incorporate a frequency doubler modulated at 30 MHz to permit operation with a single Gunn oscillator source. As a result, faster response time and somewhat greater sensitivity are obtained. The spectrometer is capable of detecting a minimum concentration of 1 ppM of SO/sub 2/ diluted in air with a 1 second time constant. For OCS diluted in air, the minimum detectable concentration is 800 ppB and with a 10 second time constant 300 ppB.

  18. Modeling in Real Time During the Ebola Response.

    PubMed

    Meltzer, Martin I; Santibanez, Scott; Fischer, Leah S; Merlin, Toby L; Adhikari, Bishwa B; Atkins, Charisma Y; Campbell, Caresse; Fung, Isaac Chun-Hai; Gambhir, Manoj; Gift, Thomas; Greening, Bradford; Gu, Weidong; Jacobson, Evin U; Kahn, Emily B; Carias, Cristina; Nerlander, Lina; Rainisch, Gabriel; Shankar, Manjunath; Wong, Karen; Washington, Michael L

    2016-01-01

    To aid decision-making during CDC's response to the 2014-2016 Ebola virus disease (Ebola) epidemic in West Africa, CDC activated a Modeling Task Force to generate estimates on various topics related to the response in West Africa and the risk for importation of cases into the United States. Analysis of eight Ebola response modeling projects conducted during August 2014-July 2015 provided insight into the types of questions addressed by modeling, the impact of the estimates generated, and the difficulties encountered during the modeling. This time frame was selected to cover the three phases of the West African epidemic curve. Questions posed to the Modeling Task Force changed as the epidemic progressed. Initially, the task force was asked to estimate the number of cases that might occur if no interventions were implemented compared with cases that might occur if interventions were implemented; however, at the peak of the epidemic, the focus shifted to estimating resource needs for Ebola treatment units. Then, as the epidemic decelerated, requests for modeling changed to generating estimates of the potential number of sexually transmitted Ebola cases. Modeling to provide information for decision-making during the CDC Ebola response involved limited data, a short turnaround time, and difficulty communicating the modeling process, including assumptions and interpretation of results. Despite these challenges, modeling yielded estimates and projections that public health officials used to make key decisions regarding response strategy and resources required. The impact of modeling during the Ebola response demonstrates the usefulness of modeling in future responses, particularly in the early stages and when data are scarce. Future modeling can be enhanced by planning ahead for data needs and data sharing, and by open communication among modelers, scientists, and others to ensure that modeling and its limitations are more clearly understood. The activities summarized in

  19. Free cortisol awakening responses are influenced by awakening time.

    PubMed

    Federenko, Ilona; Wüst, Stefan; Hellhammer, Dirk H; Dechoux, Ralph; Kumsta, Robert; Kirschbaum, Clemens

    2004-02-01

    Psychobiological investigations on the hypothalamus-pituitary-adrenal (HPA) axis depend on markers that adequately describe the activity of this system. There is evidence that the free cortisol response to awakening, proposed as a marker for the HPA axis, can be influenced by time of awakening. To further investigate this possible confounder, 24 shift working nurses and 31 female students on a regular sleep-wake cycle collected saliva samples 0, 30, 45 and 60 minutes after awakening. Nurses were investigated on the first and second day of their early (awakening: 04:00-05:30 h), late (awakening: 06:00-09:00 h), and night shift (awakening: 11:00-14:00 h), respectively. Students were studied after taking a short nap on two consecutive weekdays (awakening: 18:45-20:30 h). Mean cortisol levels after awakening increased significantly under all three shift conditions (p<0.01), but decreased in the student sample (p<.05). Within the three shift conditions, cortisol responses following waking in the early shift were more pronounced than in late (p<.01) and night shift (p<.05). The present study shows that in a sample with a large range of awakening times, an impact of this variable on the cortisol awakening response can be observed. The data furthermore strongly suggest that waking up per se is insufficient for adrenocortical stimulation. PMID:14604599

  20. Electromagnetic Real-Time Tumor Position Monitoring and Dynamic Multileaf Collimator Tracking Using a Siemens 160 MLC: Geometric and Dosimetric Accuracy of an Integrated System

    SciTech Connect

    Krauss, Andreas; Nill, Simeon; Tacke, Martin; Oelfke, Uwe

    2011-02-01

    Purpose: Dynamic multileaf collimator tracking represents a promising method for high-precision radiotherapy to moving tumors. In the present study, we report on the integration of electromagnetic real-time tumor position monitoring into a multileaf collimator-based tracking system. Methods and Materials: The integrated system was characterized in terms of its geometric and radiologic accuracy. The former was assessed from portal images acquired during radiation delivery to a phantom in tracking mode. The tracking errors were calculated from the positions of the tracking field and of the phantom as extracted from the portal images. Radiologic accuracy was evaluated from film dosimetry performed for conformal and intensity-modulated radiotherapy applied to different phantoms moving on sinusoidal trajectories. A static radiation delivery to the nonmoving target served as a reference for the delivery to the moving phantom with and without tracking applied. Results: Submillimeter tracking accuracy was observed for two-dimensional target motion despite the relatively large system latency of 500 ms. Film dosimetry yielded almost complete recovery of a circular dose distribution with tracking in two dimensions applied: 2%/2 mm gamma-failure rates could be reduced from 59.7% to 3.3%. For single-beam intensity-modulated radiotherapy delivery, accuracy was limited by the finite leaf width. A 2%/2 mm gamma-failure rate of 15.6% remained with tracking applied. Conclusion: The integrated system we have presented marks a major step toward the clinical implementation of high-precision dynamic multileaf collimator tracking. However, several challenges such as irregular motion traces or a thorough quality assurance still need to be addressed.

  1. Accuracy of familiarity decisions to famous faces perceived without awareness depends on attitude to the target person and on response latency.

    PubMed

    Stone, Anna; Valentine, Tim

    2005-06-01

    Stone and Valentine (2004) presented masked 17 ms faces in simultaneous pairs of one famous and one unfamiliar face. Accuracy in selecting the famous face was higher when the famous person was regarded as "good" or liked than when regarded as "evil" or disliked. Experiment 1 attempted to replicate this phenomenon, but produced a different pattern of results. Experiment 2 investigated alternative explanations and found evidence supporting only the effect of response latency: responses made soon after stimulus onset were more accurate to liked than to disliked faces, whereas responses made after a longer delay were equally accurate to disliked faces. It appears that the effect of negative valence was corrected within the space of a few hundred milliseconds. Experiment 3, using an affective priming paradigm, supported the concept that an early-arising effect of valence is corrected if it is misleading to the directed task. PMID:15950887

  2. Study of the time response of a LuAG(Pr) crystal for fast timing applications

    NASA Astrophysics Data System (ADS)

    Fraile, L. M.; Mach, H.; Picado, E.; Vedia, V.; Udías, J. M.

    2013-06-01

    The recently developed praseodymium-doped lutetium aluminum garnet, LuAG(Pr), holds a strong potential for fast timing applications. In this study we report on the time response of LuAG(Pr) at 22Na and 60Co photon energies. The measurements were performed using a small crystal cube of 1 cm3 coupled to a Hamamatsu R5320 photomultiplier tube. The full width at half maximum (FWHM) time resolution is found to be 147±2 ps at 60Co energies, and 238±2 ps at 22Na.

  3. Effectiveness of slow motion video compared to real time video in improving the accuracy and consistency of subjective gait analysis in dogs.

    PubMed

    Lane, D M; Hill, S A; Huntingford, J L; Lafuente, P; Wall, R; Jones, K A

    2015-01-01

    Objective measures of canine gait quality via force plates, pressure mats or kinematic analysis are considered superior to subjective gait assessment (SGA). Despite research demonstrating that SGA does not accurately detect subtle lameness, it remains the most commonly performed diagnostic test for detecting lameness in dogs. This is largely because the financial, temporal and spatial requirements for existing objective gait analysis equipment makes this technology impractical for use in general practice. The utility of slow motion video as a potential tool to augment SGA is currently untested. To evaluate a more accessible way to overcome the limitations of SGA, a slow motion video study was undertaken. Three experienced veterinarians reviewed video footage of 30 dogs, 15 with a diagnosis of primary limb lameness based on history and physical examination, and 15 with no indication of limb lameness based on history and physical examination. Four different videos were made for each dog, demonstrating each dog walking and trotting in real time, and then again walking and trotting in 50% slow motion. For each video, the veterinary raters assessed both the degree of lameness, and which limb(s) they felt represented the source of the lameness. Spearman's rho, Cramer's V, and t-tests were performed to determine if slow motion video increased either the accuracy or consistency of raters' SGA relative to real time video. Raters demonstrated no significant increase in consistency or accuracy in their SGA of slow motion video relative to real time video. Based on these findings, slow motion video does not increase the consistency or accuracy of SGA values. Further research is required to determine if slow motion video will benefit SGA in other ways. PMID:26623383

  4. Effectiveness of slow motion video compared to real time video in improving the accuracy and consistency of subjective gait analysis in dogs

    PubMed Central

    Lane, D.M.; Hill, S.A.; Huntingford, J.L.; Lafuente, P.; Wall, R.; Jones, K.A.

    2015-01-01

    Objective measures of canine gait quality via force plates, pressure mats or kinematic analysis are considered superior to subjective gait assessment (SGA). Despite research demonstrating that SGA does not accurately detect subtle lameness, it remains the most commonly performed diagnostic test for detecting lameness in dogs. This is largely because the financial, temporal and spatial requirements for existing objective gait analysis equipment makes this technology impractical for use in general practice. The utility of slow motion video as a potential tool to augment SGA is currently untested. To evaluate a more accessible way to overcome the limitations of SGA, a slow motion video study was undertaken. Three experienced veterinarians reviewed video footage of 30 dogs, 15 with a diagnosis of primary limb lameness based on history and physical examination, and 15 with no indication of limb lameness based on history and physical examination. Four different videos were made for each dog, demonstrating each dog walking and trotting in real time, and then again walking and trotting in 50% slow motion. For each video, the veterinary raters assessed both the degree of lameness, and which limb(s) they felt represented the source of the lameness. Spearman’s rho, Cramer’s V, and t-tests were performed to determine if slow motion video increased either the accuracy or consistency of raters’ SGA relative to real time video. Raters demonstrated no significant increase in consistency or accuracy in their SGA of slow motion video relative to real time video. Based on these findings, slow motion video does not increase the consistency or accuracy of SGA values. Further research is required to determine if slow motion video will benefit SGA in other ways. PMID:26623383

  5. Prospects for high accuracy time dissemination and synchronization using coded radar pulses from a low-earth orbiting spacecraft

    NASA Technical Reports Server (NTRS)

    Detoma, Edoardo V.; Dionisio, C.

    1995-01-01

    The radar (an acronym for radio detection and ranging) is an instrument developed just before the WW-II to precisely measure the position of an object (target) in space. This is done by emitting a narrow pulse of electromagnetic energy in the RF spectrum, receiving the return echo and measuring the time of flight in the two-way path from the emitter to the target. The propagation delay provides a measure of the range to the target, which is not in itself sufficient to uniquely locate the position of the same in space. However, if a directional antenna is used, the direction of the echo can be assessed by the antenna pointing angles. In this way the position of the target can be uniquely determined in space. How well this can be done is a function of the resolution of the measurements performed (range and direction, i.e.: angles); in turn, the resolution will dictate the time and frequency requirements of the reference oscillator.

  6. Time-dependent response of dissipative electron systems

    SciTech Connect

    Tremblay, Jean Christophe; Krause, Pascal; Klamroth, Tillmann; Saalfrank, Peter

    2010-06-15

    We present a systematic study of the influence of energy and phase relaxation on dynamic polarizability simulations in the linear response regime. The nonperturbative approach is based on explicit electron dynamics using short laser pulses of low intensities. To include environmental effects on the property calculation, we use the time-dependent configuration-interaction method in its reduced density matrix formulation. Both energy dissipation and nonlocal pure dephasing are included. The explicit treatment of time-resolved electron dynamics gives access to the phase shift between the electric field and the induced dipole moment, which can be used to define a useful uncertainty measure for the dynamic polarizability. The nonperturbative treatment is compared to perturbation theory expressions, as applied to a simple model system, the rigid H{sub 2} molecule. It is shown that both approaches are equivalent for low field intensities, but the time-dependent treatment provides complementary information on the phase of the induced dipole moment, which allows for the definition of an uncertainty associated with the computation of the dynamic polarizability in the linear response regime.

  7. Rasch analysis for the evaluation of rank of student response time in multiple choice examinations.

    PubMed

    Thompson, James J; Yang, Tong; Chauvin, Sheila W

    2013-01-01

    The availability of computerized testing has broadened the scope of person assessment beyond the usual accuracy-ability domain to include response time analyses. Because there are contexts in which speed is important, e.g. medical practice, it is important to develop tools by which individuals can be evaluated for speed. In this paper, the ability of Rasch measurement to convert ordinal nonparametric rankings of speed to measures is examined and compared to similar measures derived from parametric analysis of response times (pace) and semi-parametric logarithmic time-scaling procedures. Assuming that similar spans of the measures were used, non-parametric methods of raw ranking or percentile-ranking of persons by questions gave statistically acceptable person estimates of speed virtually identical to the parametric or semi-parametric methods. Because no assumptions were made about the underlying time distributions with ranking, generality of conclusions was enhanced. The main drawbacks of the non-parametric ranking procedures were the lack of information on question duration and the overall assignment by the model of variance to the person by question interaction. PMID:24064578

  8. Camera-based three-dimensional real-time particle tracking at kHz rates and Ångström accuracy

    PubMed Central

    Daldrop, Peter; Joo, Sihwa; Otto, Oliver; Keyser, Ulrich F.; Seidel, Ralf

    2014-01-01

    Optical and magnetic tweezers are widely employed to probe the mechanics and activity of individual biomolecular complexes. They rely on micrometer-sized particles to detect molecular conformational changes from the particle position. Real-time particle tracking with Ångström accuracy has so far been only achieved using laser detection through photodiodes. Here we demonstrate that camera-based imaging can provide a similar performance for all three dimensions. Particle imaging at kHz rates is combined with real-time data processing being accelerated by a graphics processing unit. For particles that are fixed in the sample cell we can detect 3 Å sized steps that are introduced by cell translations at rates of 10 Hz, while for DNA-tethered particles 5 Å steps at 1 Hz can be resolved. Moreover, 20 particles can be tracked in parallel with comparable accuracy. Our approach provides a simple and robust way for high-resolution tweezers experiments using multiple particles at a time. PMID:25565216

  9. Progress integrating ID-TIMS U-Pb geochronology with accessory mineral geochemistry: towards better accuracy and higher precision time

    NASA Astrophysics Data System (ADS)

    Schoene, B.; Samperton, K. M.; Crowley, J. L.; Cottle, J. M.

    2012-12-01

    It is increasingly common that hand samples of plutonic and volcanic rocks contain zircon with dates that span between zero and >100 ka. This recognition comes from the increased application of U-series geochronology on young volcanic rocks and the increased precision to better than 0.1% on single zircons by the U-Pb ID-TIMS method. It has thus become more difficult to interpret such complicated datasets in terms of ashbed eruption or magma emplacement, which are critical constraints for geochronologic applications ranging from biotic evolution and the stratigraphic record to magmatic and metamorphic processes in orogenic belts. It is important, therefore, to develop methods that aid in interpreting which minerals, if any, date the targeted process. One promising tactic is to better integrate accessory mineral geochemistry with high-precision ID-TIMS U-Pb geochronology. These dual constraints can 1) identify cogenetic populations of minerals, and 2) record magmatic or metamorphic fluid evolution through time. Goal (1) has been widely sought with in situ geochronology and geochemical analysis but is limited by low-precision dates. Recent work has attempted to bridge this gap by retrieving the typically discarded elution from ion exchange chemistry that precedes ID-TIMS U-Pb geochronology and analyzing it by ICP-MS (U-Pb TIMS-TEA). The result integrates geochemistry and high-precision geochronology from the exact same volume of material. The limitation of this method is the relatively coarse spatial resolution compared to in situ techniques, and thus averages potentially complicated trace element profiles through single minerals or mineral fragments. In continued work, we test the effect of this on zircon by beginning with CL imaging to reveal internal zonation and growth histories. This is followed by in situ LA-ICPMS trace element transects of imaged grains to reveal internal geochemical zonation. The same grains are then removed from grain-mount, fragmented, and

  10. Time and total dose response of non-volatile UVPROMs

    NASA Astrophysics Data System (ADS)

    Sampson, David F.

    1988-12-01

    The total-dose radiation response and intrinsic charge loss are reported as a function of operating time in a system. Five groups of 27C256 devices were aged from 1 to 5 years through accelerated bake to simulate system use. Characterizations of the groups with 5 years of simulated use are presented. The device margin voltage was characterized before and after aging and after exposure to five total-dose radiation levels, 1-5 krad (Si). A statistical model based upon the characterization data was developed to establish reprogramming intervals for these devices when they are used in airborne electronic systems.

  11. Comparison of Diagnostic Accuracy of Real-Time Elastography and Shear Wave Elastography in Differentiation Malignant From Benign Thyroid Nodules.

    PubMed

    Tian, Wuguo; Hao, Shuai; Gao, Bo; Jiang, Yan; Zhang, Shu; Guo, Lingji; Gu, Lingji; Luo, Donglin

    2015-12-01

    Thyroid nodules are relatively more prevalent in iodine-deficiency area, and the incidence increased sharply in the past decade in these areas. Workup of malignant from benign nodules in clinic was the main problem for managing thyroid nodules.An overall search for the articles about the diagnostic performance of real-time elastography (RTE) and shear wave elastography (SWE) before April 2015 in the databases of PubMed, Embase, and Google scholar. The pooled sensitivity, specificity, and summary receiver operating characteristic (SROC) curve were obtained from individual studies with a random-effects model. Subgroup and meta-regression analysis were also performed.Fifty-six studies involved in 2621 malignant nodules and 7380 benign nodules were contained in our meta-analysis. The pooled sensitivity and specificity of RTE was 83.0% and 81.2%, which is higher than SWE (sensitivity: 78.7%, specificity: 80.5%). The areas under the SROC curve of RTE and SWE were 0.885 and 0.842 respectively. RTE had higher diagnostic value for Caucasians than Asians. Stran ratio (SR) assessment had higher diagnostic performance than elasticity score (ES) system. Similarly, it had higher diagnostic value when malignant nodules were more than 50.In summary, the results revealed that RTE had higher diagnostic performance than SWE in differentiating malignant from benign nodules. However, future international multicenter studies in the region of thyroid risk need to further assess the diagnostic performance of RTE. PMID:26717367

  12. Time-dependent response of hydrogels under constrained swelling

    NASA Astrophysics Data System (ADS)

    Drozdov, A. D.; Sommer-Larsen, P.; Christiansen, J. deClaville; Sanporean, C.-G.

    2014-06-01

    Constitutive equations are developed for the viscoplastic behavior of covalently cross-linked hydrogels subjected to swelling. The ability of the model to describe the time-dependent response is confirmed by comparison of results of simulation with observations on partially swollen poly(2-hydroxyethyl methacrylate) gel specimens in uniaxial tensile tests with a constant strain rate and tensile relaxation tests. The stress-strain relations are applied to study the kinetics of unconstrained and constrained swelling. The following conclusions are drawn from numerical analysis: (i) maximum water uptake under constrained swelling a viscoplastic hydrogel is lower than that for unconstrained swelling of its elastic counterpart and exceeds maximum water uptake under constrained swelling of the elastic gel, (ii) when the rate of water diffusion exceeds the rate of plastic flow in a polymer network, swelling curves (mass uptake versus time) for viscoplastic gels under constraints demonstrate characteristic features of non-Fickian diffusion.

  13. Accuracy of matrix-assisted laser desorption ionization-time of flight mass spectrometry for identification of clinical pathogenic fungi: a meta-analysis.

    PubMed

    Ling, Huazhi; Yuan, Zhijie; Shen, Jilu; Wang, Zhongxin; Xu, Yuanhong

    2014-07-01

    Fungal infections in the clinic have become increasingly serious. In many cases, the identification of clinically relevant fungi remains time-consuming and may also be unreliable. Matrix-assisted laser desorption ionization-time of flight mass spectroscopy (MALDI-TOF MS) is a newly developed diagnostic tool that is increasingly being employed to rapidly and accurately identify clinical pathogenic microorganisms. The present meta-analysis aimed to systematically evaluate the accuracy of MALDI-TOF MS for the identification of clinical pathogenic fungi. After a rigorous selection process, 33 articles, involving 38 trials and a total of 9,977 fungal isolates, were included in the meta-analysis. The random-effects pooled identification accuracy of MALDI-TOF MS increased from 0.955 (95% confidence interval [CI], 0.939 to 0.969) at the species level to 0.977 (95% CI, 0.955 to 0.993) at the genus level (P < 0.001; χ(2) = 15.452). Subgroup analyses were performed at the species level for several categories, including strain, source of strain, system, system database, and modified outcomes, to calculate the accuracy and to investigate heterogeneity. These analyses revealed significant differences between the overall meta-analysis and some of the subanalyses. In parallel, significant differences in heterogeneity among different systems and among different methods for calculating the identification ratios were found by multivariate metaregression, but none of the factors, except for the moderator of outcome, was significantly associated with heterogeneity by univariate metaregression. In summary, the MALDI-TOF MS method is highly accurate for the identification of clinically pathogenic fungi; future studies should analyze the comprehensive capability of this technology for clinical diagnostic microbiology. PMID:24829234

  14. Accuracy of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Clinical Pathogenic Fungi: a Meta-Analysis

    PubMed Central

    Ling, Huazhi; Yuan, Zhijie; Shen, Jilu; Wang, Zhongxin

    2014-01-01

    Fungal infections in the clinic have become increasingly serious. In many cases, the identification of clinically relevant fungi remains time-consuming and may also be unreliable. Matrix-assisted laser desorption ionization–time of flight mass spectroscopy (MALDI-TOF MS) is a newly developed diagnostic tool that is increasingly being employed to rapidly and accurately identify clinical pathogenic microorganisms. The present meta-analysis aimed to systematically evaluate the accuracy of MALDI-TOF MS for the identification of clinical pathogenic fungi. After a rigorous selection process, 33 articles, involving 38 trials and a total of 9,977 fungal isolates, were included in the meta-analysis. The random-effects pooled identification accuracy of MALDI-TOF MS increased from 0.955 (95% confidence interval [CI], 0.939 to 0.969) at the species level to 0.977 (95% CI, 0.955 to 0.993) at the genus level (P < 0.001; χ2 = 15.452). Subgroup analyses were performed at the species level for several categories, including strain, source of strain, system, system database, and modified outcomes, to calculate the accuracy and to investigate heterogeneity. These analyses revealed significant differences between the overall meta-analysis and some of the subanalyses. In parallel, significant differences in heterogeneity among different systems and among different methods for calculating the identification ratios were found by multivariate metaregression, but none of the factors, except for the moderator of outcome, was significantly associated with heterogeneity by univariate metaregression. In summary, the MALDI-TOF MS method is highly accurate for the identification of clinically pathogenic fungi; future studies should analyze the comprehensive capability of this technology for clinical diagnostic microbiology. PMID:24829234

  15. Fast-Response-Time Shape-Memory-Effect Foam Actuators

    NASA Technical Reports Server (NTRS)

    Jardine, Peter

    2010-01-01

    Bulk shape memory alloys, such as Nitinol or CuAlZn, display strong recovery forces undergoing a phase transformation after being strained in their martensitic state. These recovery forces are used for actuation. As the phase transformation is thermally driven, the response time of the actuation can be slow, as the heat must be passively inserted or removed from the alloy. Shape memory alloy TiNi torque tubes have been investigated for at least 20 years and have demonstrated high actuation forces [3,000 in.-lb (approximately equal to 340 N-m) torques] and are very lightweight. However, they are not easy to attach to existing structures. Adhesives will fail in shear at low-torque loads and the TiNi is not weldable, so that mechanical crimp fits have been generally used. These are not reliable, especially in vibratory environments. The TiNi is also slow to heat up, as it can only be heated indirectly using heater and cooling must be done passively. This has restricted their use to on-off actuators where cycle times of approximately one minute is acceptable. Self-propagating high-temperature synthesis (SHS) has been used in the past to make porous TiNi metal foams. Shape Change Technologies has been able to train SHS derived TiNi to exhibit the shape memory effect. As it is an open-celled material, fast response times were observed when the material was heated using hot and cold fluids. A methodology was developed to make the open-celled porous TiNi foams as a tube with integrated hexagonal ends, which then becomes a torsional actuator with fast response times. Under processing developed independently, researchers were able to verify torques of 84 in.-lb (approximately equal to 9.5 Nm) using an actuator weighing 1.3 oz (approximately equal to 37 g) with very fast (less than 1/16th of a second) initial response times when hot and cold fluids were used to facilitate heat transfer. Integrated structural connections were added as part of the net shape process, eliminating

  16. Reproducibility and accuracy of body composition assessments in mice by dual energy x-ray absorptiometry and time domain nuclear magnetic resonance

    PubMed Central

    Halldorsdottir, Solveig; Carmody, Jill; Boozer, Carol N.; Leduc, Charles A.; Leibel, Rudolph L.

    2011-01-01

    Objective To assess the accuracy and reproducibility of dual-energy absorptiometry (DXA; PIXImus™) and time domain nuclear magnetic resonance (TD-NMR; Bruker Optics) for the measurement of body composition of lean and obese mice. Subjects and measurements Thirty lean and obese mice (body weight range 19–67 g) were studied. Coefficients of variation for repeated (x 4) DXA and NMR scans of mice were calculated to assess reproducibility. Accuracy was assessed by comparing DXA and NMR results of ten mice to chemical carcass analyses. Accuracy of the respective techniques was also assessed by comparing DXA and NMR results obtained with ground meat samples to chemical analyses. Repeated scans of 10–25 gram samples were performed to test the sensitivity of the DXA and NMR methods to variation in sample mass. Results In mice, DXA and NMR reproducibility measures were similar for fat tissue mass (FTM) (DXA coefficient of variation [CV]=2.3%; and NMR CV=2.8%) (P=0.47), while reproducibility of lean tissue mass (LTM) estimates were better for DXA (1.0%) than NMR (2.2%) (

    accuracy, in mice, DXA overestimated (vs chemical composition) LTM (+1.7 ± 1.3 g [SD], ~ 8%, P <0.001) as well as FTM (+2.0 ± 1.2 g, ~ 46%, P <0.001). NMR estimated LTM and FTM virtually identical to chemical composition analysis (LTM: −0.05 ± 0.5 g, ~0.2%, P =0.79) (FTM: +0.02 ± 0.7 g, ~15%, P =0.93). DXA and NMR-determined LTM and FTM measurements were highly correlated with the corresponding chemical analyses (r2=0.92 and r2=0.99 for DXA LTM and FTM, respectively; r2=0.99 and r2=0.99 for NMR LTM and FTM, respectively.) Sample mass did not affect accuracy in assessing chemical composition of small ground meat samples by either DXA or NMR. Conclusion DXA and NMR provide comparable levels of reproducibility in measurements of body composition lean and obese mice. While DXA and NMR measures are highly correlated with chemical analysis measures, DXA consistently overestimates LTM

  17. The effect of alcohol hangover on choice response time.

    PubMed

    Grange, James A; Stephens, Richard; Jones, Kate; Owen, Lauren

    2016-07-01

    The effect of alcohol hangover on cognitive processing has received little attention. We explored the effect of alcohol hangover on choice response time (RT), a dominant dependent variable (DV) in cognitive research. Prior research of the effect of hangover on RT has produced mixed findings; all studies reviewed relied exclusively on estimates of central tendency (e.g. mean RT), which has limited information value. Here we present novel analytical methods by going beyond mean RT analysis. Specifically, we examined performance in hangover conditions (n=31) across the whole RT distribution by fitting ex-Gaussian models to participant data, providing a formal description of the RT distribution. This analysis showed detriments to performance under hangover conditions at the slower end of the RT distribution and increased RT variance under hangover conditions. We also fitted an explicit mathematical process model of choice RT - the diffusion model - which estimates parameters reflecting psychologically-meaningful processes underlying choice RT. This analysis showed that hangover reduced information processing efficiency during response selection, and increased response caution; changes in these parameters reflect hangover affecting core decisional-components of RT performance. The implications of the data as well as the methods used for hangover research are discussed. PMID:27166364

  18. Time domain responses of hydraulic bushing with two flow passages

    NASA Astrophysics Data System (ADS)

    Chai, Tan; Dreyer, Jason T.; Singh, Rajendra

    2014-02-01

    Hydraulic bushings are commonly employed in vehicle suspension and body sub-frame systems to control motion, vibration, and structure-borne noise. Since literature on this topic is sparse, a controlled bushing prototype which accommodates a combination of long and short flow passages and flow restriction elements is first designed, constructed and instrumented. Step-up and step-down responses of several typical fluid-filled bushing configurations are measured along with steady harmonic time histories of transmitted force and internal pressures. To analyze the experimental results and gain physical insights into the hydraulic bushing system, lumped system models of bushings with different design features are developed, and analytical expressions of transmitted force and internal pressure responses are derived by using the convolution method. Parametric studies are also conducted to examine the effect of hydraulic element parameters. System parameters are successfully estimated for both harmonic and step responses using theory and measurements, and the dynamic force measurements are analyzed using analytical predictions. Finally, some nonlinearities of the system are also observed, and the fluid resistance of flow passage is found to be the most nonlinear element.

  19. SU-E-T-248: Near Real-Time Analysis of Radiation Delivery and Imaging, Accuracy to Ensure Patient Safety

    SciTech Connect

    Wijesooriya, K; Seitter, K; Desai, V; Read, P; Larner, J

    2014-06-01

    Purpose: To develop and optimize an effective software method for comparing planned to delivered control point machine parameters for all VARIAN TrueBeam treatments so as to permit (1) assessment of a large patient pool throughout their treatment course to quantify treatment technique specific systematic and random uncertainty of observables, (2) quantify the site specific daily imaging shifts required for target alignment, and (3) define tolerance levels for mechanical parameters and imaging parameters based on statistical analysis data gathered, and the dosimetric impact of variations. Methods: Treatment and imaging log files were directly compared to plan parameters for Eclipse and Pinnacle planned treatments via 3D, IMRT, control point, RapidArc, and electrons. Each control point from all beams/arcs (7984) for all fractions (1940) of all patients treated over six months were analyzed. At each control point gantry angle, collimator angle, couch angle, jaw positions, MLC positions, MU were compared. Additionally per-treatment isocenter shifts were calculated. Results were analyzed as a whole in treatment type subsets: IMRT, 3D, RapidArc; and in treatment site subsets: brain, chest/mediastinum, esophagus, H and N, lung, pelvis, prostate. Results: Daily imaging isocenter shifts from initial external tattoo alignment were dependent on the treatment site with < 0.5 cm translational shifts for H and N, Brain, and lung SBRT, while pelvis, esophagus shifts were ∼1 cm. Mechanical delivery parameters were within tolerance levels for all sub-beams. The largest variations were for RapidArc plans: gantry angle 0.11±0.12,collimator angle 0.00±0.00, jaw positions 0.48±0.26, MLC leaf positions 0.66±0.08, MU 0.14±0.34. Conclusion: Per-control point validation reveals deviations between planned and delivered parameters. If used in a near real-time error checking system, patient safety can be improved by equipping the treatment delivery system with additional forcing

  20. A general strategy for performing temperature-programming in high performance liquid chromatography--further improvements in the accuracy of retention time predictions of segmented temperature gradients.

    PubMed

    Wiese, Steffen; Teutenberg, Thorsten; Schmidt, Torsten C

    2012-01-27

    In the present work it is shown that the linear elution strength (LES) model which was adapted from temperature-programming gas chromatography (GC) can also be employed for systematic method development in high-temperature liquid chromatography (HT-HPLC). The ability to predict isothermal retention times based on temperature-gradient as well as isothermal input data was investigated. For a small temperature interval of ΔT=40°C, both approaches result in very similar predictions. Average relative errors of predicted retention times of 2.7% and 1.9% were observed for simulations based on isothermal and temperature-gradient measurements, respectively. Concurrently, it was investigated whether the accuracy of retention time predictions of segmented temperature gradients can be further improved by temperature dependent calculation of the parameter S(T) of the LES relationship. It was found that the accuracy of retention time predictions of multi-step temperature gradients can be improved to around 1.5%, if S(T) was also calculated temperature dependent. The adjusted experimental design making use of four temperature-gradient measurements was applied for systematic method development of selected food additives by high-temperature liquid chromatography. Method development was performed within a temperature interval from 40°C to 180°C using water as mobile phase. Two separation methods were established where selected food additives were baseline separated. In addition, a good agreement between simulation and experiment was observed, because an average relative error of predicted retention times of complex segmented temperature gradients less than 5% was observed. Finally, a schedule of recommendations to assist the practitioner during systematic method development in high-temperature liquid chromatography was established. PMID:22218327

  1. Ampoule failure sensor time response testing: Experiment 1

    NASA Technical Reports Server (NTRS)

    Johnson, M. L.; Watring, D. A.

    1994-01-01

    The response time of an ampoule failure sensor exposed to a liquid or vapor gallium-arsenide (GaAs) is investigated. The experimental configuration represents the sample/ampoule cartridge assembly used in NASA's Crystal Growth Furnace (CGF). The sensor is a chemical fuse made from a metal with which the semiconductor material reacts more rapidly than it does with the containing cartridge. For the III-IV compound of GaAs, a platinum metal was chosen based on the reaction of platinum and arsenic at elevated temperatures which forms a low melting eutectic. Ampoule failure is indicated by a step change in resistance of the failure sensor on the order of megohms. The sensors will increase the safety of crystal growth experiments by providing an indication that an ampoule has failed. Experimental results indicate that the response times (after a known ampoule failure) for the 0.003 and 0.010 inch ampoule failure sensors are 2.4 and 3.6 minutes, respectively. This ampoule failure sensor will be utilized in the CGF during the second United States Microgravity Laboratory Mission (USML-2) and is the subject of a NASA patent application.

  2. Accuracy of dynamic patient surface monitoring using a time-of-flight camera and B-spline modeling for respiratory motion characterization

    NASA Astrophysics Data System (ADS)

    Wentz, T.; Fayad, H.; Bert, J.; Pradier, O.; Clement, J. F.; Vourch, S.; Boussion, N.; Visvikis, D.

    2012-07-01

    Time-of-flight (ToF) camera technology provides a real-time depth map of a scene with adequate frequency for the monitoring of physiological patient motion. However, dynamic surface motion estimation using a ToF camera is limited by issues such as the raw measurement accuracy and the absence of fixed anatomical landmarks. In this work we propose to overcome these limitations using surface modeling through B-splines. This approach was assessed in terms of both motion estimation accuracy and associated variability improvements using acquisitions of an anthropomorphic surface phantom for a range of observation distances (0.6-1.4 m). In addition, feasibility was demonstrated on patient acquisitions. Using the proposed B-spline modeling, the mean motion estimation error and associated repeatability with respect to the raw measurements decreased by a factor of 3. Significant correlation was found between patients’ surfaces motion extracted using the proposed B-spline approach applied to the ToF data and the one extracted from synchronized 4D-CT acquisitions as the ground truth. ToF cameras represent a promising alternative for contact-less patient surface monitoring for respiratory motion synchronization or modeling in imaging and/or radiotherapy applications.

  3. Further improvements in deconvolution of pass-through paleomagnetic measurement data: Accuracy of positioning and sensor response

    NASA Astrophysics Data System (ADS)

    Oda, H.; Xuan, C.; Yamamoto, Y.

    2015-12-01

    Pass-through superconducting rock magnetometer (SRM) is one of the most important tools for modern paleomagnetism research. It offers rapid and continuous measurements of weak remanent magnetization preserved in various geological archives. However, pass-through SRM measurements are inevitably smoothed and even distorted due to the convolution effect of the SRM sensor response, and deconvolution is necessary to restore high-resolution signal from pass-through measurements. Reliable deconvolution relies on accurate estimate of the SRM sensor response and our understanding of errors associated with sample measurements. In this presentation, we introduce new practical tool and procedure to facilitate rapid and accurate measurements of SRM sensor response with demonstration using an SRM at the Kochi Core Center, Japan. We also report accurate measurements of SRM tray positions measured using laser interferometry. The measured positions with an actual u-channel sample on the tray show vibrations with peak amplitudes of ~50μm following each stop of the tray. The vibrations diminish towards background level in ~0.4 sec. Comparison with the positions expected from the stepping motor counts show random discrepancies with standard deviations of 0.1~0.2 mm. Measurements with u-channel show higher standard deviations including significant stepwise changes of up to ~0.5mm.

  4. Investigation into the factors affecting accuracy of mass measurements on a time-of-flight mass spectrometer using Design of Experiment.

    PubMed

    Laures, Alice M-F; Wolff, Jean-Claude; Eckers, Christine; Borman, Phil J; Chatfield, Marion J

    2007-01-01

    The results of an investigation of the parameters which have the most significant effect on the accuracy of mass measurements on a quadrupole orthogonal acceleration time-of-flight mass spectrometer (q-oaToF) are reported. The influence of eight factors is investigated: ion abundances of reference and analyte compounds, mass difference between analyte and reference compounds, quality of calibration, number of reference acquisitions averaged and TDC (time-to-digital converter) settings (resolution, Np multiplier (number of pushes correction factor), minimum number of points, i.e. minimum acquisition width which defines a peak). To extract the maximum information from as few experiments as possible, a Design of Experiment approach was used. The data will be used as a basis for developing guidance on accurate mass measurement on q-oaToF instruments. PMID:17262896

  5. Characteristics and control response of the TOPAZ II Reactor System Real-time Dynamic Simulator

    SciTech Connect

    Kwok, K.S.

    1993-11-12

    A dynamic simulator of the TOPAZ II reactor system has been developed for the Nuclear Electric Propulsion Space Test Program. The simulator combines first-principle modeling and empirical correlations in its algorithm to attain the modeling accuracy and computational through-put that are required for real-time execution. The overall execution time of the simulator for each time step is 15 ms when no data is written to the disk, and 18 ms when nine double precision data points are written to the disk once in every time step. The simulation program has been tested and it is able to handle a step decrease of $8 worth of reactivity. It also provides simulations of fuel, emitter, collector, stainless steel, and ZrH moderator failures. Presented in this paper are the models used in the calculations, a sample simulation session, and a discussion of the performance and limitations of the simulator. The simulator has been found to provide realistic real-time dynamic response of the TOPAZ II reactor system under both normal and casualty conditions.

  6. Driving time modulates accommodative response and intraocular pressure.

    PubMed

    Vera, Jesús; Diaz-Piedra, Carolina; Jiménez, Raimundo; Morales, José M; Catena, Andrés; Cardenas, David; Di Stasi, Leandro L

    2016-10-01

    Driving is a task mainly reliant on the visual system. Most of the time, while driving, our eyes are constantly focusing and refocusing between the road and the dashboard or near and far traffic. Thus, prolonged driving time should produce visual fatigue. Here, for the first time, we investigated the effects of driving time, a common inducer of driver fatigue, on two ocular parameters: the accommodative response (AR) and the intraocular pressure (IOP). A pre/post-test design has been used to assess the impact of driving time on both indices. Twelve participants (out of 17 recruited) completed the study (5 women, 24.42±2.84years old). The participants were healthy and active drivers with no visual impairment or pathology. They drove for 2h in a virtual driving environment. We assessed AR and IOP before and after the driving session, and also collected subjective measures of arousal and fatigue. We found that IOP and AR decreased (i.e., the accommodative lag increased) after the driving session (p=0.03 and p<0.001, respectively). Moreover, the nearest distances tested (20cm, 25cm, and 33cm) induced the highest decreases in AR (corrected p-values<0.05). Consistent with these findings, the subjective levels of arousal decreased and levels of fatigue increased after the driving session (all p-values<0.001). These results represent an innovative step towards an objective, valid, and reliable assessment of fatigue-impaired driving based on visual fatigue signs. PMID:27235337

  7. Designing for time-dependent material response in spacecraft structures

    NASA Technical Reports Server (NTRS)

    Hyer, M. W.; Oleksuk, Lynda L. S.; Bowles, D. E.

    1992-01-01

    To study the influence on overall deformations of the time-dependent constitutive properties of fiber-reinforced polymeric matrix composite materials being considered for use in orbiting precision segmented reflectors, simple sandwich beam models are developed. The beam models include layers representing the face sheets, the core, and the adhesive bonding of the face sheets to the core. A three-layer model lumps the adhesive layers with the face sheets or core, while a five-layer model considers the adhesive layers explicitly. The deformation response of the three-layer and five-layer sandwich beam models to a midspan point load is studied. This elementary loading leads to a simple analysis, and it is easy to create this loading in the laboratory. Using the correspondence principle of viscoelasticity, the models representing the elastic behavior of the two beams are transformed into time-dependent models. Representative cases of time-dependent material behavior for the facesheet material, the core material, and the adhesive are used to evaluate the influence of these constituents being time-dependent on the deformations of the beam. As an example of the results presented, if it assumed that, as a worst case, the polymer-dominated shear properties of the core behave as a Maxwell fluid such that under constant shear stress the shear strain increases by a factor of 10 in 20 years, then it is shown that the beam deflection increases by a factor of 1.4 during that time. In addition to quantitative conclusions, several assumptions are discussed which simplify the analyses for use with more complicated material models. Finally, it is shown that the simpler three-layer model suffices in many situations.

  8. Targeting Accuracy, Procedure Times and User Experience of 240 Experimental MRI Biopsies Guided by a Clinical Add-On Navigation System

    PubMed Central

    Busse, Harald; Riedel, Tim; Garnov, Nikita; Thörmer, Gregor; Kahn, Thomas; Moche, Michael

    2015-01-01

    Objectives MRI is of great clinical utility for the guidance of special diagnostic and therapeutic interventions. The majority of such procedures are performed iteratively ("in-and-out") in standard, closed-bore MRI systems with control imaging inside the bore and needle adjustments outside the bore. The fundamental limitations of such an approach have led to the development of various assistance techniques, from simple guidance tools to advanced navigation systems. The purpose of this work was to thoroughly assess the targeting accuracy, workflow and usability of a clinical add-on navigation solution on 240 simulated biopsies by different medical operators. Methods Navigation relied on a virtual 3D MRI scene with real-time overlay of the optically tracked biopsy needle. Smart reference markers on a freely adjustable arm ensured proper registration. Twenty-four operators – attending (AR) and resident radiologists (RR) as well as medical students (MS) – performed well-controlled biopsies of 10 embedded model targets (mean diameter: 8.5 mm, insertion depths: 17-76 mm). Targeting accuracy, procedure times and 13 Likert scores on system performance were determined (strong agreement: 5.0). Results Differences in diagnostic success rates (AR: 93%, RR: 88%, MS: 81%) were not significant. In contrast, between-group differences in biopsy times (AR: 4:15, RR: 4:40, MS: 5:06 min:sec) differed significantly (p<0.01). Mean overall rating was 4.2. The average operator would use the system again (4.8) and stated that the outcome justifies the extra effort (4.4). Lowest agreement was reported for the robustness against external perturbations (2.8). Conclusions The described combination of optical tracking technology with an automatic MRI registration appears to be sufficiently accurate for instrument guidance in a standard (closed-bore) MRI environment. High targeting accuracy and usability was demonstrated on a relatively large number of procedures and operators. Between

  9. Rapid detection of health-care-associated bloodstream infection in critical care using multipathogen real-time polymerase chain reaction technology: a diagnostic accuracy study and systematic review.

    PubMed Central

    Warhurst, Geoffrey; Dunn, Graham; Chadwick, Paul; Blackwood, Bronagh; McAuley, Daniel; Perkins, Gavin D; McMullan, Ronan; Gates, Simon; Bentley, Andrew; Young, Duncan; Carlson, Gordon L; Dark, Paul

    2015-01-01

    BACKGROUND There is growing interest in the potential utility of real-time polymerase chain reaction (PCR) in diagnosing bloodstream infection by detecting pathogen deoxyribonucleic acid (DNA) in blood samples within a few hours. SeptiFast (Roche Diagnostics GmBH, Mannheim, Germany) is a multipathogen probe-based system targeting ribosomal DNA sequences of bacteria and fungi. It detects and identifies the commonest pathogens causing bloodstream infection. As background to this study, we report a systematic review of Phase III diagnostic accuracy studies of SeptiFast, which reveals uncertainty about its likely clinical utility based on widespread evidence of deficiencies in study design and reporting with a high risk of bias. OBJECTIVE Determine the accuracy of SeptiFast real-time PCR for the detection of health-care-associated bloodstream infection, against standard microbiological culture. DESIGN Prospective multicentre Phase III clinical diagnostic accuracy study using the standards for the reporting of diagnostic accuracy studies criteria. SETTING Critical care departments within NHS hospitals in the north-west of England. PARTICIPANTS Adult patients requiring blood culture (BC) when developing new signs of systemic inflammation. MAIN OUTCOME MEASURES SeptiFast real-time PCR results at species/genus level compared with microbiological culture in association with independent adjudication of infection. Metrics of diagnostic accuracy were derived including sensitivity, specificity, likelihood ratios and predictive values, with their 95% confidence intervals (CIs). Latent class analysis was used to explore the diagnostic performance of culture as a reference standard. RESULTS Of 1006 new patient episodes of systemic inflammation in 853 patients, 922 (92%) met the inclusion criteria and provided sufficient information for analysis. Index test assay failure occurred on 69 (7%) occasions. Adult patients had been exposed to a median of 8 days (interquartile range 4

  10. Accuracy of Chronic Aquatic Toxicity Estimates Determined from Acute Toxicity Data and Two Time–Response Models.

    EPA Science Inventory

    Traditionally, chronic toxicity in aquatic organisms and wildlife has been determined from either toxicity test data, acute to chronic ratios, or application of safety factors. A more recent alternative approach has been to estimate chronic toxicity by modeling the time course of...

  11. Word Association in L1 and L2: An Exploratory Study of Response Types, Response Times, and Interlingual Mediation

    ERIC Educational Resources Information Center

    Fitzpatrick, Tess; Izura, Cristina

    2011-01-01

    Word association responses in first-language (L1) Spanish and second-language (L2) English were investigated by means of response latencies and types of associative response produced. The primary aims were to establish whether (a) some response types are produced more often or faster than others, (b) participants' L2 response time profiles mirror…

  12. Viewer response to time-varying video quality

    NASA Astrophysics Data System (ADS)

    Pearson, Don E.

    1998-07-01

    Over the past several years we have investigated viewer response to temporal fluctuations in the quality of digital television pictures, which occur when video is coded into relatively low bit rates. Three phenomena of interest have been identified: (1) a forgiveness effect, (2) a recency effect, and (3) a negative-peak (duration-neglect); these are described and discussed in the paper. In collaboration with our partners in European projects MOSAIC and TAPESTRIES, we have developed a three-stage method of measuring time-variant quality, which has been accepted by the ITU-R. The first stage is a Single Stimulus Continuous Quality Evaluation (SSCQE) of instantaneous quality; the second a calibration stage to link SSCQE with conventional DSCQS, and the third stage a numerical procedure for relating continuous and overall quality. Some of the factors we have identified as being important in producing good overall quality judgements have relevance to the design of optimal coding strategies for digital television.

  13. Field response and switching times in biaxial nematics

    NASA Astrophysics Data System (ADS)

    Berardi, Roberto; Muccioli, Luca; Zannoni, Claudio

    2008-01-01

    We study by means of virtual molecular dynamics computer experiments the response of a bulk biaxial nematic to an applied external field and, in particular, the relative speed of reorientation of the principal director axis and of the secondary one, typical of these new materials, upon a π /2 field switch. We perform the simulations setting up and integrating the equations of motion for biaxial Gay-Berne particles using quaternions and a suitable time reversible symplectic integrator. We find that switching of the secondary axis is up to an order of magnitude faster than that of the principal axis, and that under fields above a certain strength a reorganization of local domains, temporarily disrupting the nematic and biaxial ordering, rather than a collective concerted reorientation occurs.

  14. Field response and switching times in biaxial nematics.

    PubMed

    Berardi, Roberto; Muccioli, Luca; Zannoni, Claudio

    2008-01-14

    We study by means of virtual molecular dynamics computer experiments the response of a bulk biaxial nematic to an applied external field and, in particular, the relative speed of reorientation of the principal director axis and of the secondary one, typical of these new materials, upon a pi2 field switch. We perform the simulations setting up and integrating the equations of motion for biaxial Gay-Berne particles using quaternions and a suitable time reversible symplectic integrator. We find that switching of the secondary axis is up to an order of magnitude faster than that of the principal axis, and that under fields above a certain strength a reorganization of local domains, temporarily disrupting the nematic and biaxial ordering, rather than a collective concerted reorientation occurs. PMID:18205473

  15. Study on desirable ionospheric corrections accuracy for network-RTK positioning and its impact on time-to-fix and probability of successful single-epoch ambiguity resolution

    NASA Astrophysics Data System (ADS)

    Paziewski, Jacek

    2016-02-01

    The mitigation of ionospheric delay is still of crucial interest in GNSS positioning, especially in precise solutions such as instantaneous RTK positioning. Thus, several effective algorithms and functional models were developed, and also numerous investigations of ionospheric correction properties in RTK positioning have been performed so far. One of the most highly effective approaches in precise relative positioning is the application of the ionosphere-weighted model with network-derived corrections. This contribution investigates the impact of the accuracy of the network ionospheric corrections on time-to-fix in RTK-OTF positioning. Also, an attempt has been made to estimate the desirable accuracy of the network ionospheric corrections, allowing for reliable instantaneous ambiguity resolution. The experiment is based on a multi-baseline GPS RTK positioning supported with network-derived ionospheric corrections for medium length baselines. The results show that in such scenario, the double-differenced ionospheric correction residuals should not exceed ∼1/3 of the L1 wavelength for successful single-epoch ambiguity resolution.

  16. GPS computer navigators to shorten EMS response and transport times.

    PubMed

    Ota, F S; Muramatsu, R S; Yoshida, B H; Yamamoto, L G

    2001-05-01

    GPS (global positioning satellite system to determine one's position on earth) units have become inexpensive and compact. The purpose of this study is to assess the effectiveness of a GPS enhanced computer street map navigator to improve the ability of EMS drivers in an urban setting to locate their destination and shorten response times. For part I, residential addresses in the city were randomly selected from a telephone directory. Two driver/navigator teams were assigned to drive to the address adhering to speed limits. One team used a standard street map, whereas the other team used a GPS computer navigator. The travel time and distance of the runs were compared. For part II, the computer GPS navigator was placed on an ambulance to supplement their normal methods of navigation to find the address requesting EMS. After the run was completed, EMS providers were interviewed to determine their opinion of whether the GPS navigator was helpful. For part I the results showed that in the 29 initial test runs, comparing the GPS team versus the standard map team, the mean distances traveled were 8.7 versus 9.0 kilometers (not significant) and the mean travel times were 13.5 versus 14.6 minutes (P=.02), respectively. The GPS team arrived faster in 72% runs. For part II the results showed that most EMS providers surveyed noted that the GPS computer navigator enhanced their ability to find the destination and all EMS providers acknowledged that it would enhance their ability to find a destination in an area in which they were unfamiliar. These results suggest that a portable GPS computer navigator system is helpful and can enhance the ability of prehospital care providers to locate their destination. Because these units are accurate and inexpensive, GPS computer navigators may be a valuable tool in reducing pre-hospital transport times. PMID:11326345

  17. SU-E-T-346: Validation of Beam Accuracy of a Gated Spot-Scanning Proton Therapy System with Real-Time Tumor-Tracking at Hokkaido University

    SciTech Connect

    Yamada, T; Matsuura, T; Toramatsu, C; Takao, S; Nihongi, H; Miyamoto, N; Shimizu, S; Shirato, H; Takayanagi, T; Umezawa, M; Matsuda, K; Umegaki, K

    2014-06-01

    Purpose: At Hokkaido University, we have developed a gated spot scanning proton beam therapy system with real-time tumor-tracking under collaborative work with Hitachi Ltd. This system has the ability to gate proton beams from the synchrotron, turning the beam on only when the actual positions of inserted fiducial markers monitored by two fluoroscopic X-ray systems are within the planned positions [Shirato, 2012]. In this research, we validated the accuracy of the proton beams while utilizing external gating signals. Methods: The accuracy of spot positions, spot dose, absolute dose at the center of the SOBP, and range were measured while utilizing external gating signals. The following external gating signals were generated by an arbitrary waveform generator: (1) ON at all times (without gating), (2) an OFF period of 4 s followed by an ON period of 1 s, (3) two ON periods of 0.5 s with a 0.15 s OFF interval, (4) signals recorded during the treatment of real-time tumor-tracking X-ray therapy in Hokkaido University. The spot positions and spot dose were measured by beam monitors in the nozzle. The ranges were measured with a multi-layer ion chamber made by Hitachi Ltd. The absolute dose was measured with a Farmer ionization chamber and a RFA300 water phantom system. Results: The maximum error of the beam position in the isocenter plane was 0.8 mm without the gating signal and 1.0 mm with the gating signal. The maximum error of the spot dose was 0.0029 MU, below the criterion of 0.0032 MU. The maximum error of the absolute dose was 0.4% and the maximum variation of the range was 0.1 mm. Conclusion: It was confirmed with measurements of the beam that the accuracy of the proton beam met the criteria with external gating signals. This research was supported by the Cabinet Office, Government of Japan and the Japan Society for the Promotion of Science (JSPS) through the Funding Program for World-Leading Innovative R and D on Science and Technology (FIRST Program

  18. Combining Blink, Pupil, and Response Time Measures in a Concealed Knowledge Test

    PubMed Central

    Seymour, Travis L.; Baker, Christopher A.; Gaunt, Joshua T.

    2013-01-01

    The response time (RT) based Concealed Knowledge Test (CKT) has been shown to accurately detect participants’ knowledge of mock-crime-related information. Tests based on ocular measures such as pupil-size and blink-rate have sometimes resulted in poor classification, or lacked detailed classification analyses. The present study examines the fitness of multiple pupil and blink related responses in the CKT paradigm. To maximize classification efficiency, participants’ concealed knowledge was assessed using both individual test measures and combinations of test measures. Results show that individual pupil-size, pupil-slope, and pre-response blink-rate measures produce efficient classifications. Combining pupil and blink measures yielded more accuracy classifications than individual ocular measures. Although RT-based tests proved efficient, combining RT with ocular measures had little incremental benefit. It is argued that covertly assessing ocular measures during RT-based tests may guard against effective countermeasure use in applied settings. A compound classification procedure was used to categorize individual participants and yielded high hit rates and low false-alarm rates without the need for adjustments between test paradigms and subject populations. We conclude that with appropriate test paradigms and classification analyses, ocular measures may prove as effective as other indices, though additional research is needed. PMID:23382718

  19. Speed/accuracy tradeoff in force perception.

    PubMed

    Rank, Markus; Di Luca, Massimiliano

    2015-06-01

    There is a well-known tradeoff between speed and accuracy in judgments made under uncertainty. Diffusion models have been proposed to capture the increase in response time for more uncertain decisions and the change in performance due to a prioritization of speed or accuracy in the responses. Experimental paradigms have been confined to the visual modality and model analysis have mostly used quantile-probability (QP) plots--response probability as a function of quantized RTs. Here, we extend diffusion modeling to haptics and test a novel type of analysis for judging model fitting. Participants classified force stimuli applied to the hand as "high" or "low." Data in QP plots indicate that the diffusion model captures well the overall pattern of responses in conditions where either speed or accuracy has been prioritized. To further the analysis, we compute just noticeable difference (JND) values separately for responses delivered with different RTs--we define these plots as JND quantile. The pattern of results evidences that slower responses lead to better force discrimination up to a plateau that is unaffected by prioritization instructions. Instead, the diffusion model predicts two well-separated plateaus depending on the condition. We propose that analyzing the relation between JNDs and response time should be considered in the evaluation of the diffusion model beyond the haptic modality, thus including vision. PMID:25867512

  20. Holistic approach using accuracy of diffraction-based integrated metrology to improve on-product performance, reduce cycle time, and cost at litho

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Kaustuve; den Boef, Arie; Jak, Martin; Zhang, Gary; Maassen, Martijn; Tijssen, Robin; Adam, Omer; Fuchs, Andreas; Zhang, Youping; Huang, Jacky; Couraudon, Vincent; Tzeng, Wilson; Su, Eason; Wang, Cathy; Kavanagh, Jim; Fouquet, Christophe

    2015-03-01

    High-end semiconductor lithography requirements for CD, focus and overlay control drive the need for diffraction-based metrology1,2,3,4 and integrated metrology5. In the advanced nodes, more complex lithography techniques (such as multiple patterning), use of multi-layer overlay measurements in process control, advanced device designs (such as advanced FinFET), as well as advanced materials (like hardmasks) are introduced. These pose new challenges for lithometro cycle time, cost, process control and metrology accuracy. In this publication a holistic approach is taken to face these challenges via a novel target design, a brand new implementation of multi-layer overlay measurement capability in diffraction-based mode and integrated metrology.

  1. Real-Time Drug Release Analysis of Enzyme and pH Responsive Polysaccharide Nanovesicles.

    PubMed

    Pramod, Poothayil Subash; Deshpande, Nilesh Umakant; Jayakannan, Manickam

    2015-08-20

    The accurate estimation of drug release kinetics of polymeric vehicles is an indispensable prerequisite for the developments of successful drug carriers for cancer therapy. The present investigation reports the development of time-resolved fluorescence spectroscopic approach for the real-time release kinetics of fluorophore loaded polysaccharide vesicles that are potential vectors in cancer treatment. The polysaccharide vesicles were custom designed with appropriate enzyme and pH responsiveness and loaded with water-soluble biocompatible fluorophore Rhodamine B (Rh-B). The semipermeable membrane dialysis method along with steady state absorbance spectroscopic technique was found to be inaccurate for the estimation of drug release. Time correlated single photon counting (TCSPC) technique was found to exhibit significant difference in excited state decay profiles and fluorescent lifetime of Rh-B in the free and polymer bound states. This enabled the establishment of real-time drug release protocols by TCSPC method for polysaccharide vesicles that are responsible to pH and enzyme with respect to intracellular compartments. Real-time analysis predicted the release kinetics 20-25% higher accuracy when compared to the dialysis method under in vitro conditions. Moreover, the ability of enzyme to cleave the polysaccharide vesicles was further validated by docking studies. The positioning of the molecules in active site of enzyme and the binding energy data were generated using AUTODOCK program to study the rupture of polysaccharide vesicles. This new TCSPC technique could be very useful for studying the drug release pattern of synthetic polymer vesicles loaded with Rh-B fluorophore. PMID:26237375

  2. Accuracy of erythrogram and serum ferritin for the maternal anemia diagnosis (AMA): a phase 3 diagnostic study on prediction of the therapeutic responsiveness to oral iron in pregnancy

    PubMed Central

    2013-01-01

    Background Pregnancy anemia remains as a public health problem, since the official reports in the 70’s. To guide the treatment of iron-deficiency anemia in pregnancy, the haemoglobin concentration is the most used test in spite of its low accuracy, and serum ferritin is the most reliable test, although its cutoff point remains an issue. Methods/design The aim of this protocol is to verify the accuracy of erythrocyte indices and serum ferritin (studied tests) for the diagnosis of functional iron-deficiency in pregnancy using the iron-therapy responsiveness as the gold-standard. This is an ongoing phase III accuracy study initiated in August 2011 and to be concluded in April 2013. The subjects are anemic pregnant women (haemoglobin concentration < 11.0 g/dL) attended at a low-risk prenatal care center in the Northeast of Brazil. The sample size (n 278) was calculated to estimate sensitivity of 90% and 80% of specificity with relative error of 10% and power of 95%. This study has a prospective design with a before-after intervention of 80 mg of daily oral iron during 90 days and will be analyzed as a delayed-type cross-sectional study. Women at the second trimester of pregnancy are being evaluated with clinical and laboratorial examinations at the enrollment and monthly. The ‘responsiveness to therapeutic test with oral iron’ (gold-standard) was defined to an increase of at least 0.55 Z-score in haemoglobin after 4 weeks of treatment and a total dose of 1200 mg of iron. At the study conclusion, sensitivities, specificities, predictive values, likelihood ratios and areas under the ROC (Receiver Operating Characteristic) curves of serum ferritin and erythrocyte indices (red blood cell count, haematocrit, haemoglobin concentration, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, red blood cell distribution width, reticulocyte count) will be tested. The compliance and adverse effects are considered

  3. The Response Time of a Rotor System with a Disk-Type Magnetorheological Fluid Damper

    NASA Astrophysics Data System (ADS)

    Zhu, Changsheng

    The response time of a rotor system supported upon a disk-type magnetorheological fluid damper operating on shear mode is measured experimentally. The effects of rotating speed, step current and magnetic particle volume fraction, on the response time are dealt with. It is shown that the dynamic response can be described by first 10% response time and rapid response time. Generally, the first 10% response time and the rapid response time are in order of less than 0.1 second and 0.1~0.4 second. The magnetic field strength, magnetic particle volume fraction and power supply have a great effect on the response time. The response time in dropping step current is several times longer than that in applying step current. There is a zero initial delay time at either applying or dropping the current, which is caused by the magnetizing or de-magnetizing process.

  4. Heat-Treatment-Responsive Proteins in Different Developmental Stages of Tomato Pollen Detected by Targeted Mass Accuracy Precursor Alignment (tMAPA).

    PubMed

    Chaturvedi, Palak; Doerfler, Hannes; Jegadeesan, Sridharan; Ghatak, Arindam; Pressman, Etan; Castillejo, Maria Angeles; Wienkoop, Stefanie; Egelhofer, Volker; Firon, Nurit; Weckwerth, Wolfram

    2015-11-01

    Recently, we have developed a quantitative shotgun proteomics strategy called mass accuracy precursor alignment (MAPA). The MAPA algorithm uses high mass accuracy to bin mass-to-charge (m/z) ratios of precursor ions from LC-MS analyses, determines their intensities, and extracts a quantitative sample versus m/z ratio data alignment matrix from a multitude of samples. Here, we introduce a novel feature of this algorithm that allows the extraction and alignment of proteotypic peptide precursor ions or any other target peptide from complex shotgun proteomics data for accurate quantification of unique proteins. This strategy circumvents the problem of confusing the quantification of proteins due to indistinguishable protein isoforms by a typical shotgun proteomics approach. We applied this strategy to a comparison of control and heat-treated tomato pollen grains at two developmental stages, post-meiotic and mature. Pollen is a temperature-sensitive tissue involved in the reproductive cycle of plants and plays a major role in fruit setting and yield. By LC-MS-based shotgun proteomics, we identified more than 2000 proteins in total for all different tissues. By applying the targeted MAPA data-processing strategy, 51 unique proteins were identified as heat-treatment-responsive protein candidates. The potential function of the identified candidates in a specific developmental stage is discussed. PMID:26419256

  5. High accuracy OMEGA timekeeping

    NASA Technical Reports Server (NTRS)

    Imbier, E. A.

    1982-01-01

    The Smithsonian Astrophysical Observatory (SAO) operates a worldwide satellite tracking network which uses a combination of OMEGA as a frequency reference, dual timing channels, and portable clock comparisons to maintain accurate epoch time. Propagational charts from the U.S. Coast Guard OMEGA monitor program minimize diurnal and seasonal effects. Daily phase value publications of the U.S. Naval Observatory provide corrections to the field collected timing data to produce an averaged time line comprised of straight line segments called a time history file (station clock minus UTC). Depending upon clock location, reduced time data accuracies of between two and eight microseconds are typical.

  6. Structural Equation Model Approach to the Use of Response Times for Improving Estimation in Item Response Models

    ERIC Educational Resources Information Center

    Sen, Rohini

    2012-01-01

    In the last five decades, research on the uses of response time has extended into the field of psychometrics (Schnikpe & Scrams, 1999; van der Linden, 2006; van der Linden, 2007), where interest has centered around the usefulness of response time information in item calibration and person measurement within an item response theory. framework.…

  7. Revealing Real-Time Emotional Responses: a Personalized Assessment based on Heartbeat Dynamics

    NASA Astrophysics Data System (ADS)

    Valenza, Gaetano; Citi, Luca; Lanatá, Antonio; Scilingo, Enzo Pasquale; Barbieri, Riccardo

    2014-05-01

    Emotion recognition through computational modeling and analysis of physiological signals has been widely investigated in the last decade. Most of the proposed emotion recognition systems require relatively long-time series of multivariate records and do not provide accurate real-time characterizations using short-time series. To overcome these limitations, we propose a novel personalized probabilistic framework able to characterize the emotional state of a subject through the analysis of heartbeat dynamics exclusively. The study includes thirty subjects presented with a set of standardized images gathered from the international affective picture system, alternating levels of arousal and valence. Due to the intrinsic nonlinearity and nonstationarity of the RR interval series, a specific point-process model was devised for instantaneous identification considering autoregressive nonlinearities up to the third-order according to the Wiener-Volterra representation, thus tracking very fast stimulus-response changes. Features from the instantaneous spectrum and bispectrum, as well as the dominant Lyapunov exponent, were extracted and considered as input features to a support vector machine for classification. Results, estimating emotions each 10 seconds, achieve an overall accuracy in recognizing four emotional states based on the circumplex model of affect of 79.29%, with 79.15% on the valence axis, and 83.55% on the arousal axis.

  8. Revealing Real-Time Emotional Responses: a Personalized Assessment based on Heartbeat Dynamics

    PubMed Central

    Valenza, Gaetano; Citi, Luca; Lanatá, Antonio; Scilingo, Enzo Pasquale; Barbieri, Riccardo

    2014-01-01

    Emotion recognition through computational modeling and analysis of physiological signals has been widely investigated in the last decade. Most of the proposed emotion recognition systems require relatively long-time series of multivariate records and do not provide accurate real-time characterizations using short-time series. To overcome these limitations, we propose a novel personalized probabilistic framework able to characterize the emotional state of a subject through the analysis of heartbeat dynamics exclusively. The study includes thirty subjects presented with a set of standardized images gathered from the international affective picture system, alternating levels of arousal and valence. Due to the intrinsic nonlinearity and nonstationarity of the RR interval series, a specific point-process model was devised for instantaneous identification considering autoregressive nonlinearities up to the third-order according to the Wiener-Volterra representation, thus tracking very fast stimulus-response changes. Features from the instantaneous spectrum and bispectrum, as well as the dominant Lyapunov exponent, were extracted and considered as input features to a support vector machine for classification. Results, estimating emotions each 10 seconds, achieve an overall accuracy in recognizing four emotional states based on the circumplex model of affect of 79.29%, with 79.15% on the valence axis, and 83.55% on the arousal axis. PMID:24845973

  9. Separable responses to error, ambiguity, and reaction time in cingulo-opercular task control regions.

    PubMed

    Neta, Maital; Schlaggar, Bradley L; Petersen, Steven E

    2014-10-01

    The dorsal anterior cingulate (dACC), along with the closely affiliated anterior insula/frontal operculum, have been demonstrated to show three types of task control signals across a wide variety of tasks. One of these signals, a transient signal that is thought to represent performance feedback, shows greater activity to error than correct trials. Other work has found similar effects for uncertainty/ambiguity or conflict, though some argue that dACC activity is, instead, modulated primarily by other processes more reflected in reaction time. Here, we demonstrate that, rather than a single explanation, multiple information processing operations are crucial to characterizing the function of these brain regions, by comparing operations within a single paradigm. Participants performed two tasks in an fMRI experimental session: (1) deciding whether or not visually presented word pairs rhyme, and (2) rating auditorily presented single words as abstract or concrete. A pilot was used to identify ambiguous stimuli for both tasks (e.g., word pair: BASS/GRACE; single word: CHANGE). We found greater cingulo-opercular activity for errors and ambiguous trials than clear/correct trials, with a robust effect of reaction time. The effects of error and ambiguity remained when reaction time was regressed out, although the differences decreased. Further stepwise regression of response consensus (agreement across participants for each stimulus; a proxy for ambiguity) decreased differences between ambiguous and clear trials, but left error-related differences almost completely intact. These observations suggest that trial-wise responses in cingulo-opercular regions monitor multiple performance indices, including accuracy, ambiguity, and reaction time. PMID:24887509

  10. Unraveling the drivers of the storm time radiation belt response

    NASA Astrophysics Data System (ADS)

    Kilpua, E. K. J.; Hietala, H.; Turner, D. L.; Koskinen, H. E. J.; Pulkkinen, T. I.; Rodriguez, J. V.; Reeves, G. D.; Claudepierre, S. G.; Spence, H. E.

    2015-05-01

    We present a new framework to study the time evolution and dynamics of the outer Van Allen belt electron fluxes. The framework is entirely based on the large-scale solar wind storm drivers and their substructures. The Van Allen Probe observations, revealing the electron flux behavior throughout the outer belt, are combined with continuous, long-term (over 1.5 solar cycles) geosynchronous orbit data set from GOES and solar wind measurements A superposed epoch analysis, where we normalize the timescales for each substructure (sheath, ejecta, and interface region) allows us to avoid smearing effects and to distinguish the electron flux evolution during various driver structures. We show that the radiation belt response is not random: The electron flux variations are determined by the combined effect of the structured solar wind driver and prestorm electron flux levels. In particular, we find that loss mechanisms dominate during stream interface regions, coronal mass ejection (CME) ejecta, and sheaths while enhancements occur during fast streams trailing the stream interface or the CME.

  11. Improving OCD time to solution using Signal Response Metrology

    NASA Astrophysics Data System (ADS)

    Fang, Fang; Zhang, Xiaoxiao; Vaid, Alok; Pandev, Stilian; Sanko, Dimitry; Ramanathan, Vidya; Venkataraman, Kartik; Haupt, Ronny

    2016-03-01

    In recent technology nodes, advanced process and novel integration scheme have challenged the precision limits of conventional metrology; with critical dimensions (CD) of device reduce to sub-nanometer region. Optical metrology has proved its capability to precisely detect intricate details on the complex structures, however, conventional RCWA-based (rigorous coupled wave analysis) scatterometry has the limitations of long time-to-results and lack of flexibility to adapt to wide process variations. Signal Response Metrology (SRM) is a new metrology technique targeted to alleviate the consumption of engineering and computation resources by eliminating geometric/dispersion modeling and spectral simulation from the workflow. This is achieved by directly correlating the spectra acquired from a set of wafers with known process variations encoded. In SPIE 2015, we presented the results of SRM application in lithography metrology and control [1], accomplished the mission of setting up a new measurement recipe of focus/dose monitoring in hours. This work will demonstrate our recent field exploration of SRM implementation in 20nm technology and beyond, including focus metrology for scanner control; post etch geometric profile measurement, and actual device profile metrology.

  12. Real-time Responsiveness for Ethics Oversight During Disaster Research.

    PubMed

    Eckenwiler, Lisa; Pringle, John; Boulanger, Renaud; Hunt, Matthew

    2015-11-01

    Disaster research has grown in scope and frequency. Research in the wake of disasters and during humanitarian crises--particularly in resource-poor settings--is likely to raise profound and unique ethical challenges for local communities, crisis responders, researchers, and research ethics committees (RECs). Given the ethical challenges, many have questioned how best to provide research ethics review and oversight. We contribute to the conversation concerning how best to ensure appropriate ethical oversight in disaster research and argue that ethical disaster research requires of researchers and RECs a particular sort of ongoing, critical engagement which may not be warranted in less exceptional research. We present two cases that typify the concerns disaster researchers and RECs may confront, and elaborate upon what this ongoing engagement might look like--how it might be conceptualized and utilized--using the concept of real-time responsiveness (RTR). The central aim of RTR, understood here as both an ethical ideal and practice, is to lessen the potential for research conducted in the wake of disasters to create, perpetuate, or exacerbate vulnerabilities and contribute to injustices suffered by disaster-affected populations. Well cultivated and deployed, we believe that RTR may enhance the moral capacities of researchers and REC members, and RECs as institutions where moral agency is nurtured and sustained. PMID:26481207

  13. Reaction Time and Accuracy in Erroneous vs Correct Responses among Dyslexic and Regular Readers: From Letters to Sentences

    ERIC Educational Resources Information Center

    Horowitz-Kraus, Tzipi; Breznitz, Zvia

    2011-01-01

    Speed of processing (SOP) is a crucial factor in fluent reading and is measured using reading rate. This measure is commonly used to examine correct reading patterns, yet in the present study it is employed to determine whether differences in SOP exist for correct and incorrect reading. One of the characteristics of dyslexia is slow and inaccurate…

  14. A Proton Beam Therapy System Dedicated to Spot-Scanning Increases Accuracy with Moving Tumors by Real-Time Imaging and Gating and Reduces Equipment Size

    PubMed Central

    Shimizu, Shinichi; Miyamoto, Naoki; Matsuura, Taeko; Fujii, Yusuke; Umezawa, Masumi; Umegaki, Kikuo; Hiramoto, Kazuo; Shirato, Hiroki

    2014-01-01

    Purpose A proton beam therapy (PBT) system has been designed which dedicates to spot-scanning and has a gating function employing the fluoroscopy-based real-time-imaging of internal fiducial markers near tumors. The dose distribution and treatment time of the newly designed real-time-image gated, spot-scanning proton beam therapy (RGPT) were compared with free-breathing spot-scanning proton beam therapy (FBPT) in a simulation. Materials and Methods In-house simulation tools and treatment planning system VQA (Hitachi, Ltd., Japan) were used for estimating the dose distribution and treatment time. Simulations were performed for 48 motion parameters (including 8 respiratory patterns and 6 initial breathing timings) on CT data from two patients, A and B, with hepatocellular carcinoma and with clinical target volumes 14.6 cc and 63.1 cc. The respiratory patterns were derived from the actual trajectory of internal fiducial markers taken in X-ray real-time tumor-tracking radiotherapy (RTRT). Results With FBPT, 9/48 motion parameters achieved the criteria of successful delivery for patient A and 0/48 for B. With RGPT 48/48 and 42/48 achieved the criteria. Compared with FBPT, the mean liver dose was smaller with RGPT with statistical significance (p<0.001); it decreased from 27% to 13% and 28% to 23% of the prescribed doses for patients A and B, respectively. The relative lengthening of treatment time to administer 3 Gy (RBE) was estimated to be 1.22 (RGPT/FBPT: 138 s/113 s) and 1.72 (207 s/120 s) for patients A and B, respectively. Conclusions This simulation study demonstrated that the RGPT was able to improve the dose distribution markedly for moving tumors without very large treatment time extension. The proton beam therapy system dedicated to spot-scanning with a gating function for real-time imaging increases accuracy with moving tumors and reduces the physical size, and subsequently the cost of the equipment as well as of the building housing the equipment. PMID

  15. Bayesian Procedures for Identifying Aberrant Response-Time Patterns in Adaptive Testing

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Guo, Fanmin

    2008-01-01

    In order to identify aberrant response-time patterns on educational and psychological tests, it is important to be able to separate the speed at which the test taker operates from the time the items require. A lognormal model for response times with this feature was used to derive a Bayesian procedure for detecting aberrant response times.…

  16. The clinical diagnostic accuracy of rapid detection of healthcare-associated bloodstream infection in intensive care using multipathogen real-time PCR technology

    PubMed Central

    Dunn, Graham; Chadwick, Paul; Young, Duncan; Bentley, Andrew; Carlson, Gordon; Warhurst, Geoffrey

    2011-01-01

    Background There is growing interest in the potential utility of real-time PCR in diagnosing bloodstream infection by detecting pathogen DNA in blood samples within a few hours. SeptiFast is a multipathogen probe-based real-time PCR system targeting ribosomal DNA sequences of bacteria and fungi. It detects and identifies the commonest pathogens causing bloodstream infection and has European regulatory approval. The SeptiFast pathogen panel is suited to identifying healthcare-associated bloodstream infection acquired during complex healthcare, and the authors report here the protocol for the first detailed health-technology assessment of multiplex real-time PCR in this setting. Methods/design A Phase III multicentre double-blinded diagnostic study will determine the clinical validity of SeptiFast for the rapid detection of healthcare-associated bloodstream infection, against the current service standard of microbiological culture, in an adequately sized population of critically ill adult patients. Results from SeptiFast and standard microbiological culture procedures in each patient will be compared at study conclusion and the metrics of clinical diagnostic accuracy of SeptiFast determined in this population setting. In addition, this study aims to assess further the preliminary evidence that the detection of pathogen DNA in the bloodstream using SeptiFast may have value in identifying the presence of infection elsewhere in the body. Furthermore, differences in circulating immune-inflammatory markers in patient groups differentiated by the presence/absence of culturable pathogens and pathogen DNA will help elucidate further the patho-physiology of infection developing in the critically ill. Ethics and dissemination Ethical approval has been granted by the North West 6 Research Ethics Committee (09/H1003/109). Based on the results of this first non-commercial study, independent recommendations will be made to The Department of Health (open-access health technology

  17. Interoceptive accuracy and panic.

    PubMed

    Zoellner, L A; Craske, M G

    1999-12-01

    Psychophysiological models of panic hypothesize that panickers focus attention on and become anxious about the physical sensations associated with panic. Attention on internal somatic cues has been labeled interoception. The present study examined the role of physiological arousal and subjective anxiety on interoceptive accuracy. Infrequent panickers and nonanxious participants participated in an initial baseline to examine overall interoceptive accuracy. Next, participants ingested caffeine, about which they received either safety or no safety information. Using a mental heartbeat tracking paradigm, participants' count of their heartbeats during specific time intervals were coded based on polygraph measures. Infrequent panickers were more accurate in the perception of their heartbeats than nonanxious participants. Changes in physiological arousal were not associated with increased accuracy on the heartbeat perception task. However, higher levels of self-reported anxiety were associated with superior performance. PMID:10596462

  18. Modulation of Response Timing in ADHD, Effects of Reinforcement Valence and Magnitude

    ERIC Educational Resources Information Center

    Luman, Marjolein; Oosterlaan, Jaap; Sergeant, Joseph A.

    2008-01-01

    The present study investigated the impact of reinforcement valence and magnitude on response timing in children with ADHD. Children were required to estimate a 1-s interval, and both the median response time (response tendency) and the intrasubject-variability (response stability) were investigated. In addition, heart rate and skin conductance…

  19. An Analysis of Variance Approach for the Estimation of Response Time Distributions in Tests

    ERIC Educational Resources Information Center

    Attali, Yigal

    2010-01-01

    Generalizability theory and analysis of variance methods are employed, together with the concept of objective time pressure, to estimate response time distributions and the degree of time pressure in timed tests. By estimating response time variance components due to person, item, and their interaction, and fixed effects due to item types and…

  20. Anticipating by Pigeons Depends on Local Statistical Information in a Serial Response Time Task

    ERIC Educational Resources Information Center

    Froehlich, Alyson L.; Herbranson, Walter T.; Loper, Julia D.; Wood, David M.; Shimp, Charles P.

    2004-01-01

    Pigeons responded in a serial response time task patterned after that of M. J. Nissen and P. Bullemer (1987) with humans. Experiment 1 produced global facilitation: Response times in repeating lists of locations were faster than when locations were random. Response time to a spatial location was also a function of both that location's 1st- and…

  1. Fractionated Reaction Time Responses to Auditory and Electrocutaneous Stimuli.

    ERIC Educational Resources Information Center

    Beehler, Pamela J. Hoyes; Kamen, Gary

    1986-01-01

    An investigation was conducted to equate auditory and electrocutaneous stimuli. These equated stimuli were used in a second investigation examining neuromotor responses to stimuli of varying intensity. Results are provided. (Author/MT)

  2. Prediction of delayed treatment response in pulmonary tuberculosis: use of time to positivity values of Bactec cultures.

    PubMed

    Carroll, N M; Uys, P; Hesseling, A; Lawrence, K; Pheiffer, C; Salker, F; Duncan, K; Beyers, N; van Helden, P D

    2008-11-01

    New drugs that can shorten tuberculosis (TB) treatment and target drug resistant strains are urgently needed. A test which could predict patients at risk of a delayed response to treatment would facilitate clinical trials of new anti-tuberculosis drugs. A widely-used test for the assessment of response to treatment is sputum smear examination. Patients who are smear positive after 2 and 3 months of treatment are said to have delayed and significantly delayed treatment responses respectively. Time to positivity (TTP) values of Bactec cultures, from the first 2 weeks of treatment were used to predict delayed and significantly delayed treatment responses in patients with first time pulmonary tuberculosis. Changes in TTP values early in treatment were transformed to a response ratio (r). Values of r that were less than a threshold value (r(c)) indicated patients who were at risk of having delayed or significantly delayed response to treatment. Accuracy of prediction was sensitive to the timing of sputum sampling and adherence to therapy in the first 2 weeks. Based on TTP data from the first 2 weeks of treatment, significantly delayed treatment response could be predicted with a sensitivity of 75% and a specificity of 62% while the positive (PPV) and negative predictive values (NPV) were 14% and 97% respectively. While the high NPV indicates that a large proportion of patients with a satisfactory response to treatment can be reliably identified, the low PPV value underlines the need to use TTP in conjunction with other markers of disease activity to predict unfavourable treatment response in tuberculosis treatment. PMID:18456556

  3. A frequency response analysis approach for quantitative assessment of actuator tracking for real-time hybrid simulation

    NASA Astrophysics Data System (ADS)

    Guo, Tong; Chen, Cheng; Xu, WeiJie; Sanchez, Frank

    2014-04-01

    Real-time hybrid simulation is a viable and economical technique that allows researchers to observe the behavior of critical elements at full scale when an entire structure is subjected to dynamic loading. To ensure reliable experimental results, it is necessary to evaluate the actuator tracking after the test, even when sophisticated compensation methods are used to negate the detrimental effect of servo-hydraulic dynamics. Existing methods for assessment of actuator tracking are often based on time-domain analysis. This paper proposes a frequency-domain-based approach to the assessment of actuator tracking for real-time hybrid simulations. To ensure the accuracy of the proposed frequency response approach, the effects of spectrum leakage are investigated as well as the length and sampling frequency requirements of the signals. Two signal pre-processing techniques (data segmentation and window transform) are also discussed and compared to improve the accuracy of the proposed approach. Finally the effectiveness of the proposed frequency-domain-based approach is demonstrated through both computational analyses and laboratory tests, including real-time tests with predefined displacement and real-time hybrid simulation.

  4. Limited information estimation of the diffusion-based item response theory model for responses and response times.

    PubMed

    Ranger, Jochen; Kuhn, Jörg-Tobias; Szardenings, Carsten

    2016-05-01

    Psychological tests are usually analysed with item response models. Recently, some alternative measurement models have been proposed that were derived from cognitive process models developed in experimental psychology. These models consider the responses but also the response times of the test takers. Two such models are the Q-diffusion model and the D-diffusion model. Both models can be calibrated with the diffIRT package of the R statistical environment via marginal maximum likelihood (MML) estimation. In this manuscript, an alternative approach to model calibration is proposed. The approach is based on weighted least squares estimation and parallels the standard estimation approach in structural equation modelling. Estimates are determined by minimizing the discrepancy between the observed and the implied covariance matrix. The estimator is simple to implement, consistent, and asymptotically normally distributed. Least squares estimation also provides a test of model fit by comparing the observed and implied covariance matrix. The estimator and the test of model fit are evaluated in a simulation study. Although parameter recovery is good, the estimator is less efficient than the MML estimator. PMID:26853083

  5. Considering Time in Orthophotography Production: from a General Workflow to a Shortened Workflow for a Faster Disaster Response

    NASA Astrophysics Data System (ADS)

    Lucas, G.

    2015-08-01

    This article overall deals with production time with orthophoto imagery with medium size digital frame camera. The workflow examination follows two main parts: data acquisition and post-processing. The objectives of the research are fourfold: 1/ gathering time references for the most important steps of orthophoto production (it turned out that literature is missing on this topic); these figures are used later for total production time estimation; 2/ identifying levers for reducing orthophoto production time; 3/ building a simplified production workflow for emergency response: less exigent with accuracy and faster; and compare it to a classical workflow; 4/ providing methodical elements for the estimation of production time with a custom project. In the data acquisition part a comprehensive review lists and describes all the factors that may affect the acquisition efficiency. Using a simulation with different variables (average line length, time of the turns, flight speed) their effect on acquisition efficiency is quantitatively examined. Regarding post-processing, the time references figures were collected from the processing of a 1000 frames case study with 15 cm GSD covering a rectangular area of 447 km2; the time required to achieve each step during the production is written down. When several technical options are possible, each one is tested and time documented so as all alternatives are available. Based on a technical choice with the workflow and using the compiled time reference of the elementary steps, a total time is calculated for the post-processing of the 1000 frames. Two scenarios are compared as regards to time and accuracy. The first one follows the "normal" practices, comprising triangulation, orthorectification and advanced mosaicking methods (feature detection, seam line editing and seam applicator); the second is simplified and make compromise over positional accuracy (using direct geo-referencing) and seamlines preparation in order to achieve

  6. Brainstem auditory evoked responses in man. 1: Effect of stimulus rise-fall time and duration

    NASA Technical Reports Server (NTRS)

    Hecox, K.; Squires, N.; Galambos, R.

    1975-01-01

    Short latency (under 10 msec) responses elicited by bursts of white noise were recorded from the scalps of human subjects. Response alterations produced by changes in the noise burst duration (on-time), inter-burst interval (off-time), and onset and offset shapes were analyzed. The latency of the most prominent response component, wave V, was markedly delayed with increases in stimulus rise time but was unaffected by changes in fall time. Increases in stimulus duration, and therefore in loudness, resulted in a systematic increase in latency. This was probably due to response recovery processes, since the effect was eliminated with increases in stimulus off-time. The amplitude of wave V was insensitive to changes in signal rise and fall times, while increasing signal on-time produced smaller amplitude responses only for sufficiently short off-times. It was concluded that wave V of the human auditory brainstem evoked response is solely an onset response.

  7. Motherhood and drug-dependency: the attributes of full-time versus part-time responsibility for child care.

    PubMed

    Jackson, M R; Berry, G L

    1994-10-01

    This study examined differences between the maternal characteristics of African-American drug-dependent mothers who have full-time responsibility for child care and those having part-time responsibility. The study revealed that full-time mothers have significantly higher levels of maternal adaptation than part-time mothers. For part-time mothers, the level of maternal adaptation or self-esteem did not fluctuate, regardless of whether she saw the child 4 days a week or once a month. The article identifies variables that may facilitate better maternal behaviors among drug-dependent mothers. PMID:7836017

  8. Leveraging First Response Time into the Knowledge Tracing Model

    ERIC Educational Resources Information Center

    Wang, Yutao; Heffernan, Neil T.

    2012-01-01

    The field of educational data mining has been using the Knowledge Tracing model, which only look at the correctness of student first response, for tracking student knowledge. Recently, lots of other features are studied to extend the Knowledge Tracing model to better model student knowledge. The goal of this paper is to analyze whether or not the…

  9. Utilizing Response Time Distributions for Item Selection in CAT

    ERIC Educational Resources Information Center

    Fan, Zhewen; Wang, Chun; Chang, Hua-Hua; Douglas, Jeffrey

    2012-01-01

    Traditional methods for item selection in computerized adaptive testing only focus on item information without taking into consideration the time required to answer an item. As a result, some examinees may receive a set of items that take a very long time to finish, and information is not accrued as efficiently as possible. The authors propose two…

  10. Online versus offline: The Web as a medium for response time data collection.

    PubMed

    Chetverikov, Andrey; Upravitelev, Philipp

    2016-09-01

    The Internet provides a convenient environment for data collection in psychology. Modern Web programming languages, such as JavaScript or Flash (ActionScript), facilitate complex experiments without the necessity of experimenter presence. Yet there is always a question of how much noise is added due to the differences between the setups used by participants and whether it is compensated for by increased ecological validity and larger sample sizes. This is especially a problem for experiments that measure response times (RTs), because they are more sensitive (and hence more susceptible to noise) than, for example, choices per se. We used a simple visual search task with different set sizes to compare laboratory performance with Web performance. The results suggest that although the locations (means) of RT distributions are different, other distribution parameters are not. Furthermore, the effect of experiment setting does not depend on set size, suggesting that task difficulty is not important in the choice of a data collection method. We also collected an additional online sample to investigate the effects of hardware and software diversity on the accuracy of RT data. We found that the high diversity of browsers, operating systems, and CPU performance may have a detrimental effect, though it can partly be compensated for by increased sample sizes and trial numbers. In sum, the findings show that Web-based experiments are an acceptable source of RT data, comparable to a common keyboard-based setup in the laboratory. PMID:26170056

  11. Clinical Evaluation of Spatial Accuracy of a Fusion Imaging Technique Combining Previously Acquired Computed Tomography and Real-Time Ultrasound for Imaging of Liver Metastases

    SciTech Connect

    Hakime, Antoine Deschamps, Frederic; Garcia Marques de Carvalho, Enio; Teriitehau, Christophe; Auperin, Anne; De Baere, Thierry

    2011-04-15

    Purpose: This study was designed to evaluate the spatial accuracy of matching volumetric computed tomography (CT) data of hepatic metastases with real-time ultrasound (US) using a fusion imaging system (VNav) according to different clinical settings. Methods: Twenty-four patients with one hepatic tumor identified on enhanced CT and US were prospectively enrolled. A set of three landmarks markers was chosen on CT and US for image registration. US and CT images were then superimposed using the fusion imaging display mode. The difference in spatial location between the tumor visible on the CT and the US on the overlay images (reviewer no. 1, comment no. 2) was measured in the lateral, anterior-posterior, and vertical axis. The maximum difference (Dmax) was evaluated for different predictive factors.CT performed 1-30 days before registration versus immediately before. Use of general anesthesia for CT and US versus no anesthesia.Anatomic landmarks versus landmarks that include at least one nonanatomic structure, such as a cyst or a calcificationResultsOverall, Dmax was 11.53 {+-} 8.38 mm. Dmax was 6.55 {+-} 7.31 mm with CT performed immediately before VNav versus 17.4 {+-} 5.18 with CT performed 1-30 days before (p < 0.0001). Dmax was 7.05 {+-} 6.95 under general anesthesia and 16.81 {+-} 6.77 without anesthesia (p < 0.0015). Landmarks including at least one nonanatomic structure increase Dmax of 5.2 mm (p < 0.0001). The lowest Dmax (1.9 {+-} 1.4 mm) was obtained when CT and VNav were performed under general anesthesia, one immediately after the other. Conclusions: VNav is accurate when adequate clinical setup is carefully selected. Only under these conditions (reviewer no. 2), liver tumors not identified on US can be accurately targeted for biopsy or radiofrequency ablation using fusion imaging.

  12. Generalized time-dependent density-functional-theory response functions for spontaneous density fluctuations and nonlinear response: Resolving the causality paradox in real time

    SciTech Connect

    Mukamel, Shaul

    2005-02-01

    Time-ordered superoperators are used to develop a unified description of nonlinear density response and spontaneous fluctuations of many-electron systems. The pth-order density response functions are decomposed into 2{sup p+1} non-causal Liouville space pathways. Individual pathways are symmetric to the interchange of their space, time, and superoperator indices and can thus be calculated as functional derivatives. Other combinations of these pathways represent spontaneous density fluctuations and the response of such fluctuations to an external field. The resolution of the causality paradox of time-dependent density-functional theory (TDDFT) is shown to be intimately connected with the nonretarded nature of fluctuations.

  13. Genes influence the amplitude and timing of brain hemodynamic responses.

    PubMed

    Shan, Zuyao Y; Vinkhuyzen, Anna A E; Thompson, Paul M; McMahon, Katie L; Blokland, Gabriëlla A M; de Zubicaray, Greig I; Calhoun, Vince; Martin, Nicholas G; Visscher, Peter M; Wright, Margaret J; Reutens, David C

    2016-01-01

    In functional magnetic resonance imaging (fMRI), the hemodynamic response function (HRF) reflects regulation of regional cerebral blood flow in response to neuronal activation. The HRF varies significantly between individuals. This study investigated the genetic contribution to individual variation in HRF using fMRI data from 125 monozygotic (MZ) and 149 dizygotic (DZ) twin pairs. The resemblance in amplitude, latency, and duration of the HRF in six regions in the frontal and parietal lobes was compared between MZ and DZ twin pairs. Heritability was estimated using an ACE (Additive genetic, Common environmental, and unique Environmental factors) model. The genetic influence on the temporal profile and amplitude of HRF was moderate to strong (24%-51%). The HRF may be used in the genetic analysis of diseases with a cerebrovascular etiology. PMID:26375212

  14. Accuracy of deception judgments.

    PubMed

    Bond, Charles F; DePaulo, Bella M

    2006-01-01

    We analyze the accuracy of deception judgments, synthesizing research results from 206 documents and 24,483 judges. In relevant studies, people attempt to discriminate lies from truths in real time with no special aids or training. In these circumstances, people achieve an average of 54% correct lie-truth judgments, correctly classifying 47% of lies as deceptive and 61% of truths as nondeceptive. Relative to cross-judge differences in accuracy, mean lie-truth discrimination abilities are nontrivial, with a mean accuracy d of roughly .40. This produces an effect that is at roughly the 60th percentile in size, relative to others that have been meta-analyzed by social psychologists. Alternative indexes of lie-truth discrimination accuracy correlate highly with percentage correct, and rates of lie detection vary little from study to study. Our meta-analyses reveal that people are more accurate in judging audible than visible lies, that people appear deceptive when motivated to be believed, and that individuals regard their interaction partners as honest. We propose that people judge others' deceptions more harshly than their own and that this double standard in evaluating deceit can explain much of the accumulated literature. PMID:16859438

  15. Real-time earthquake monitoring: Early warning and rapid response

    NASA Technical Reports Server (NTRS)

    1991-01-01

    A panel was established to investigate the subject of real-time earthquake monitoring (RTEM) and suggest recommendations on the feasibility of using a real-time earthquake warning system to mitigate earthquake damage in regions of the United States. The findings of the investigation and the related recommendations are described in this report. A brief review of existing real-time seismic systems is presented with particular emphasis given to the current California seismic networks. Specific applications of a real-time monitoring system are discussed along with issues related to system deployment and technical feasibility. In addition, several non-technical considerations are addressed including cost-benefit analysis, public perceptions, safety, and liability.

  16. 5 CFR 1820.4 - Timing of responses to requests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... simple and more complex requests based on the amount of work and/or time needed to process the request... out of order and given expedited treatment whenever OSC has established to its satisfaction that:...

  17. 5 CFR 1820.4 - Timing of responses to requests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... simple and more complex requests based on the amount of work and/or time needed to process the request... out of order and given expedited treatment whenever OSC has established to its satisfaction that:...

  18. The Impact of Item Format and Examinee Characteristics on Response Times

    ERIC Educational Resources Information Center

    Hess, Brian J.; Johnston, Mary M.; Lipner, Rebecca S.

    2013-01-01

    Current research on examination response time has focused on tests comprised of traditional multiple-choice items. Consequently, the impact of other innovative or complex item formats on examinee response time is not understood. The present study used multilevel growth modeling to investigate examinee characteristics associated with response time…

  19. Using Response Time to Detect Item Preknowledge in Computer-Based Licensure Examinations

    ERIC Educational Resources Information Center

    Qian, Hong; Staniewska, Dorota; Reckase, Mark; Woo, Ada

    2016-01-01

    This article addresses the issue of how to detect item preknowledge using item response time data in two computer-based large-scale licensure examinations. Item preknowledge is indicated by an unexpected short response time and a correct response. Two samples were used for detecting item preknowledge for each examination. The first sample was from…

  20. 75 FR 37712 - Temporary Suspension of Certain Oil Spill Response Time Requirements To Support Deepwater Horizon...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-30

    ...; 2050-AG63 Temporary Suspension of Certain Oil Spill Response Time Requirements To Support Deepwater Horizon Oil Spill of National Significance (SONS) Response AGENCIES: Coast Guard, DHS, and Environmental... Environmental Protection Agency (EPA) temporary interim rule will suspend oil spill response time...

  1. Enabling high grayscale resolution displays and accurate response time measurements on conventional computers.

    PubMed

    Li, Xiangrui; Lu, Zhong-Lin

    2012-01-01

    Display systems based on conventional computer graphics cards are capable of generating images with 8-bit gray level resolution. However, most experiments in vision research require displays with more than 12 bits of luminance resolution. Several solutions are available. Bit++ (1) and DataPixx (2) use the Digital Visual Interface (DVI) output from graphics cards and high resolution (14 or 16-bit) digital-to-analog converters to drive analog display devices. The VideoSwitcher (3) described here combines analog video signals from the red and blue channels of graphics cards with different weights using a passive resister network (4) and an active circuit to deliver identical video signals to the three channels of color monitors. The method provides an inexpensive way to enable high-resolution monochromatic displays using conventional graphics cards and analog monitors. It can also provide trigger signals that can be used to mark stimulus onsets, making it easy to synchronize visual displays with physiological recordings or response time measurements. Although computer keyboards and mice are frequently used in measuring response times (RT), the accuracy of these measurements is quite low. The RTbox is a specialized hardware and software solution for accurate RT measurements. Connected to the host computer through a USB connection, the driver of the RTbox is compatible with all conventional operating systems. It uses a microprocessor and high-resolution clock to record the identities and timing of button events, which are buffered until the host computer retrieves them. The recorded button events are not affected by potential timing uncertainties or biases associated with data transmission and processing in the host computer. The asynchronous storage greatly simplifies the design of user programs. Several methods are available to synchronize the clocks of the RTbox and the host computer. The RTbox can also receive external triggers and be used to measure RT with respect

  2. Real-time Monitoring of Radiofrequency Ablation and Postablation Assessment: Accuracy of Contrast-enhanced US in Experimental Rat Liver Model

    PubMed Central

    Wu, Hanping; Wilkins, Luke R.; Ziats, Nicholas P.; Haaga, John R.

    2014-01-01

    Purpose To examine the accuracy of the unenhanced zone at contrast material–enhanced ultrasonography (US) in predicting coagulative necrosis during and 21 days after radiofrequency (RF) ablation by using radiologic-pathologic comparison. Materials and methods Animal studies were approved by the Institutional Animal Care and Use Committee. The livers of 28 rats underwent US-guided RF ablation. In four animals, contrast-enhanced US was performed during ablation and 2 hours and 2, 7, 14, and 21 days after ablation. The unenhanced zone area on US images was measured. DiI-labeled microbubbles were administered during ablation at 2, 4, and 6 minutes or at 2 hours and 2, 7, 14, and 21 days after ablation in the remaining 24 animals (n = 3 at each time point). One minute later, the animal was euthanized, and the ablated liver was harvested. Tissue samples were imaged to quantify total fluorescence, and NADH staining was performed on the same slice. Hematoxylin-eosin staining was also performed. The findings on fluorescence images, NADH-stained images, and hematoxylin-eosin–stained images were compared. The areas of DiI bubble–negative zones, NADH-negative zones, and lightly NADH-staining zones were measured. Data were analyzed by using one-way analysis of variance. Results The area of the unenhanced zone on contrast-enhanced US images increased during RF ablation and reached a maximum within 2 days after ablation. At histopathologic examination, a transition zone manifested adjacent to the coagulation zone until 2 days after ablation. The DiI-bubble negative zone on fluorescence images and the damaged zone (transition zone plus coagulation zone) on NADH-stained images increased rapidly within 2 hours after ablation, then slowly reached the maximum on day 2. The ratios of the mean areas of these two zones at hour 2 to those at day 2 were 94.6% and 95.6%, respectively. High uniformity between the damaged zone on NADH-stained images and the DiI bubble–negative zone on

  3. Brainstem auditory evoked responses in man. 1: Effect of stimulus rise-fall time and duration

    NASA Technical Reports Server (NTRS)

    Hecox, K.; Squires, N.; Galambos, R.

    1975-01-01

    Short latency (under 10 msec) evoked responses elicited by bursts of white noise were recorded from the scalp of human subjects. Response alterations produced by changes in the noise burst duration (on-time) inter-burst interval (off-time), and onset and offset shapes are reported and evaluated. The latency of the most prominent response component, wave V, was markedly delayed with increases in stimulus rise-time but was unaffected by changes in fall-time. The amplitude of wave V was insensitive to changes in signal rise-and-fall times, while increasing signal on-time produced smaller amplitude responses only for sufficiently short off-times. It is concluded that wave V of the human auditory brainstem evoked response is solely an onset response.

  4. A Multivariate Multilevel Approach to the Modeling of Accuracy and Speed of Test Takers

    ERIC Educational Resources Information Center

    Klein Entink, R. H.; Fox, J. P.; van der Linden, W. J.

    2009-01-01

    Response times on test items are easily collected in modern computerized testing. When collecting both (binary) responses and (continuous) response times on test items, it is possible to measure the accuracy and speed of test takers. To study the relationships between these two constructs, the model is extended with a multivariate multilevel…

  5. Harnessing data structure for recovery of randomly missing structural vibration responses time history: Sparse representation versus low-rank structure

    NASA Astrophysics Data System (ADS)

    Yang, Yongchao; Nagarajaiah, Satish

    2016-06-01

    Randomly missing data of structural vibration responses time history often occurs in structural dynamics and health monitoring. For example, structural vibration responses are often corrupted by outliers or erroneous measurements due to sensor malfunction; in wireless sensing platforms, data loss during wireless communication is a common issue. Besides, to alleviate the wireless data sampling or communication burden, certain accounts of data are often discarded during sampling or before transmission. In these and other applications, recovery of the randomly missing structural vibration responses from the available, incomplete data, is essential for system identification and structural health monitoring; it is an ill-posed inverse problem, however. This paper explicitly harnesses the data structure itself-of the structural vibration responses-to address this (inverse) problem. What is relevant is an empirical, but often practically true, observation, that is, typically there are only few modes active in the structural vibration responses; hence a sparse representation (in frequency domain) of the single-channel data vector, or, a low-rank structure (by singular value decomposition) of the multi-channel data matrix. Exploiting such prior knowledge of data structure (intra-channel sparse or inter-channel low-rank), the new theories of ℓ1-minimization sparse recovery and nuclear-norm-minimization low-rank matrix completion enable recovery of the randomly missing or corrupted structural vibration response data. The performance of these two alternatives, in terms of recovery accuracy and computational time under different data missing rates, is investigated on a few structural vibration response data sets-the seismic responses of the super high-rise Canton Tower and the structural health monitoring accelerations of a real large-scale cable-stayed bridge. Encouraging results are obtained and the applicability and limitation of the presented methods are discussed.

  6. Quantized response times are a signature of a neuronal bottleneck in decision.

    PubMed

    Perona, Pietro

    2014-01-01

    The histograms of response times of optimal YES/NO decisions that are computed from a single sensory Poisson neuron are highly structured. In particular, response times in NO decisions are quantized to a small set of times, while response times in YES decisions have a multimodal structure. Both the times of NO decisions, as well as the modes of the the histogram of YES decisions, are associated to the number of action potentials that were necessary to reach the decision. Their value is a function of the firing rate of the neuron in response to the states of the stimulus. PMID:24782750

  7. Correlations between liquid crystal director reorientation and optical response time of a homeotropic cell

    NASA Astrophysics Data System (ADS)

    Wang, Haiying; Wu, Thomas X.; Zhu, Xinyu; Wu, Shin-Tson

    2004-05-01

    Correlations between the director reorientation time and its consequent optical response time (both decay and rise) of a homeotropic liquid crystal (LC) cell under crossed polarizers are derived theoretically based on small angle approximation. Results indicate that the optical response time is linearly proportional to the LC director reorientation time and is weakly dependent on the initial bias voltage. To validate the derived correlations, transient phase and transmittance responses at various bias voltages are analyzed numerically by solving the Erickson-Leslie equation. Pretilt angle is found to make an important contribution to the optical response time. Gray scale switching of the homeotropic cell is also investigated.

  8. Overeating at dinner time among Japanese workers: Is overeating related to stress response and late dinner times?

    PubMed

    Suzuki, Akiko; Sakurazawa, Hirofumi; Fujita, Takanori; Akamatsu, Rie

    2016-06-01

    There are several known risk factors for overeating, including negative feelings and hunger. It was hypothesized that overtime work is associated with stress responses and later dinner times, leading to longer periods of time without eating, and that this, in turn, leads to a strong experience of hunger and consequent overeating at dinner. The aim of this study was to examine relationships among overeating at dinner, stress responses (e.g., fatigue, anxiety, and depression), and dinner times in Japanese male workers. In December 2012, 255 Japanese male workers at a leasing company completed a self-report questionnaire about overeating at dinner, psychological stress responses, physical stress responses, and dinner times. Each worker was sent an email with a link to the questionnaire website, where his answers were collected. Relationships between overeating at dinner and lifestyle issues were investigated using multiple linear regression analysis treating overeating as a dependent variable. Factors related to overeating at dinner included psychological stress response (β = 0.251 p < 0.001) and dinner time (β = 0.220, p = 0.004). These cross-sectional data suggest that overeating at dinner is related to dinner time in men and to stress responses. PMID:26923743

  9. Use of Constant Time Delay and Attentional Responses with Adolescents.

    ERIC Educational Resources Information Center

    Wolery, Mark; And Others

    1991-01-01

    This study examined effectiveness of a constant time delay (CTD) procedure in teaching social studies and health facts to five adolescents with learning or behavioral disorders. Students were given praise with and without additional information. Results indicated CTD procedures were reliable and effective, and students acquired nontargeted as well…

  10. Time-Varying Affective Response for Humanoid Robots

    NASA Astrophysics Data System (ADS)

    Moshkina, Lilia; Arkin, Ronald C.; Lee, Jamee K.; Jung, Hyunryong

    This paper describes the design of a complex time-varying affective architecture. It is an expansion of the TAME architecture (traits, attitudes, moods, and emotions) as applied to humanoid robotics. It particular it is intended to promote effective human-robot interaction by conveying the robot’s affective state to the user in an easy-to-interpret manner.

  11. INTERNAL DOSE AND RESPONSE IN REAL-TIME.

    EPA Science Inventory

    Abstract: Rapid temporal fluctuations in exposure may occur in a number of situations such as accidents or other unexpected acute releases of airborne substances. Often risk assessments overlook temporal exposure patterns under simplifying assumptions such as the use of time-wei...

  12. Physiological Evidence for Response Inhibition in Choice Reaction Time Tasks

    ERIC Educational Resources Information Center

    Burle, Boris; Vidal, Frank; Tandonnet, Christophe; Hasbroucq, Thierry

    2004-01-01

    Inhibition is a widely used notion proposed to account for data obtained in choice reaction time (RT) tasks. However, this concept is weakly supported by empirical facts. In this paper, we review a series of experiments using Hoffman reflex, transcranial magnetic stimulation and electroencephalography to study inhibition in choice RT tasks. We…

  13. High Accuracy Fuel Flowmeter, Phase 1

    NASA Technical Reports Server (NTRS)

    Mayer, C.; Rose, L.; Chan, A.; Chin, B.; Gregory, W.

    1983-01-01

    Technology related to aircraft fuel mass - flowmeters was reviewed to determine what flowmeter types could provide 0.25%-of-point accuracy over a 50 to one range in flowrates. Three types were selected and were further analyzed to determine what problem areas prevented them from meeting the high accuracy requirement, and what the further development needs were for each. A dual-turbine volumetric flowmeter with densi-viscometer and microprocessor compensation was selected for its relative simplicity and fast response time. An angular momentum type with a motor-driven, spring-restrained turbine and viscosity shroud was selected for its direct mass-flow output. This concept also employed a turbine for fast response and a microcomputer for accurate viscosity compensation. The third concept employed a vortex precession volumetric flowmeter and was selected for its unobtrusive design. Like the turbine flowmeter, it uses a densi-viscometer and microprocessor for density correction and accurate viscosity compensation.

  14. B-mode, real-time ultrasound for estimating carcass composition in live sheep: Accuracy of ultrasound measures and their relationships with carcass composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The accuracy and repeatability of live-animal ultrasound measures, and the relationships of these measures with carcass yield, composition, and value, were investigated using data from 172 wethers. Wethers were F1 progeny from the mating of 4 terminal sire breeds to Rambouillet ewes, and were finis...

  15. Accuracy of the electron transport in mcnp5 and its suitability for ionization chamber response simulations: A comparison with the egsnrc and penelope codes

    SciTech Connect

    Koivunoro, Hanna; Siiskonen, Teemu; Kotiluoto, Petri; Auterinen, Iiro; Hippelaeinen, Eero; Savolainen, Sauli

    2012-03-15

    Purpose: In this work, accuracy of the mcnp5 code in the electron transport calculations and its suitability for ionization chamber (IC) response simulations in photon beams are studied in comparison to egsnrc and penelope codes. Methods: The electron transport is studied by comparing the depth dose distributions in a water phantom subdivided into thin layers using incident energies (0.05, 0.1, 1, and 10 MeV) for the broad parallel electron beams. The IC response simulations are studied in water phantom in three dosimetric gas materials (air, argon, and methane based tissue equivalent gas) for photon beams ({sup 60}Co source, 6 MV linear medical accelerator, and mono-energetic 2 MeV photon source). Two optional electron transport models of mcnp5 are evaluated: the ITS-based electron energy indexing (mcnp5{sub ITS}) and the new detailed electron energy-loss straggling logic (mcnp5{sub new}). The electron substep length (ESTEP parameter) dependency in mcnp5 is investigated as well. Results: For the electron beam studies, large discrepancies (>3%) are observed between the mcnp5 dose distributions and the reference codes at 1 MeV and lower energies. The discrepancy is especially notable for 0.1 and 0.05 MeV electron beams. The boundary crossing artifacts, which are well known for the mcnp5{sub ITS}, are observed for the mcnp5{sub new} only at 0.1 and 0.05 MeV beam energies. If the excessive boundary crossing is eliminated by using single scoring cells, the mcnp5{sub ITS} provides dose distributions that agree better with the reference codes than mcnp5{sub new}. The mcnp5 dose estimates for the gas cavity agree within 1% with the reference codes, if the mcnp5{sub ITS} is applied or electron substep length is set adequately for the gas in the cavity using the mcnp5{sub new}. The mcnp5{sub new} results are found highly dependent on the chosen electron substep length and might lead up to 15% underestimation of the absorbed dose. Conclusions: Since the mcnp5 electron

  16. Meteorological data assimilation for real-time emergency response

    SciTech Connect

    Sugiyama, G.; Chan, S.T.

    1996-11-01

    The US Department of Energy`s Atmospheric Release Advisory Capability (ARAC) provides real-time dose assessments of airborne pollutant releases. Diverse data assimilation techniques are required to meet the needs of a new generation of ARAC models and to take advantage of the rapidly expanding availability of meteorological data. We are developing a hierarchy of algorithms to provide gridded meteorological fields which can be used to drive dispersion codes or to provide initial fields for mesoscale models. Data to be processed include winds, temperature, moisture, and turbulence.

  17. Time-domain solution for transient dynamic response of a large-diameter thin-walled pipe pile

    NASA Astrophysics Data System (ADS)

    Ding, Xuanming; Liu, Hanlong; Chu, Jian; Cheng, Ke

    2015-06-01

    The propagation of stress waves in a large-diameter pipe pile for low strain dynamic testing cannot be explained properly by traditional 1D wave theories. A new computational model is established to obtain a wave equation that can describe the dynamic response of a large-diameter thin-walled pipe pile to a transient point load during a low strain integrity test. An analytical solution in the time domain is deduced using the separation of variables and variation of constant methods. The validity of this new solution is verified by an existing analytical solution under free boundary conditions. The results of this time domain solution are also compared with the results of a frequency domain solution and field test data. The comparisons indicate that the new solution agrees well with the results of previous solutions. Parametric studies using the new solution with reference to a case study are also carried out. The results show that the mode number affects the accuracy of the dynamic response. A mode number greater than 10 is required to enable the calculated dynamic responses to be independent of the mode number. The dynamic response is also greatly affected by soil properties. The larger the side resistance, the smaller the displacement response and the smaller the reflected velocity wave crest. The displacement increases as the stress waves propagate along the pile when the pile shaft is free. The incident waves of displacement and velocity responses of the pile are not the same among different points in the circumferential direction on the pile top. However, the arrival time and peak value of the pile tip reflected waves are almost the same among different points on the pile top.

  18. Time-Dependent Response Versus Scan Angle for MODIS Reflective Solar Bands

    NASA Technical Reports Server (NTRS)

    Sun, Junqiang; Xiong, Xiaoxiong; Angal, Amit; Chen, Hongda; Wu, Aisheng; Geng, Xu

    2014-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) instruments currently operate onboard the National Aeronautics and Space Administration (NASA's) Terra and Aqua spacecraft, launched on December 18, 1999 and May 4, 2002, respectively. MODIS has 36 spectral bands, among which 20 are reflective solar bands (RSBs) covering a spectral range from 0.412 to 2.13 µm. The RSBs are calibrated on orbit using a solar diffuser (SD) and an SD stability monitor and with additional measurements from lunar observations via a space view (SV) port. Selected pseudo-invariant desert sites are also used to track the RSB on-orbit gain change, particularly for short-wavelength bands. MODIS views the Earth surface, SV, and the onboard calibrators using a two-sided scan mirror. The response versus scan angle (RVS) of the scan mirror was characterized prior to launch, and its changes are tracked using observations made at different angles of incidence from onboard SD, lunar, and Earth view (EV) measurements. These observations show that the optical properties of the scan mirror have experienced large wavelength-dependent degradation in both the visible and near infrared spectral regions. Algorithms have been developed to track the on-orbit RVS change using the calibrators and the selected desert sites. These algorithms have been applied to both Terra and Aqua MODIS Level 1B (L1B) to improve the EV data accuracy since L1B Collection 4, refined in Collection 5, and further improved in the latest Collection 6 (C6). In C6, two approaches have been used to derive the time-dependent RVS for MODIS RSB. The first approach relies on data collected from sensor onboard calibrators and mirror side ratios from EV observations. The second approach uses onboard calibrators and EV response trending from selected desert sites. This approach is mainly used for the bands with much larger changes in their time-dependent RVS, such as the Terra MODIS bands 1-4, 8, and 9 and the Aqua MODIS bands 8- and 9

  19. Age-related differences in predictive response timing in children: evidence from regularly relative to irregularly paced reaction time performance.

    PubMed

    Debrabant, Julie; Gheysen, Freja; Vingerhoets, Guy; Van Waelvelde, Hilde

    2012-08-01

    Predictive timing refers to the anticipation and precise timing of planned motor responses. This study was performed to investigate children's predictive response timing abilities while accounting for confounding age-related effects of motor speed. Indices of predictive timing were evaluated for their contributions in motor skill proficiency as well. Eighty typically developing children in 4 age groups (5-6, 7-8, 9-10 and 11-12 years) performed a visuomotor reaction time (RT) test. Differences in speed and anticipatory responding at regularly relative to irregularly paced stimuli were evaluated as indices of predictive timing. Also, explicit timing and motor tests (M-ABC-2, VMI tracing, and KTK jumping) were administered. Significant faster responding for regularly versus irregularly paced stimuli was found from the ages of 9-10 years on. Better anticipatory responding behavior for regular in contrast with irregular stimuli was found to be present already at 7-8 years. Overall, predictive timing abilities increased across the 4 age groups. Also, inter-individual differences in the speed indices of predictive timing contributed to predicting VMI tracing and KTK jumping outcomes when controlling for age and overall motor response speed. In conclusion, predictive motor timing abilities increase during age 5 to 12 and correlate with motor skill performance. PMID:22494922

  20. Do Young and Old Preschoolers Exhibit Response Bias Due to Different Mechanisms? Investigating Children's Response Time

    ERIC Educational Resources Information Center

    Okanda, Mako; Itakura, Shoji

    2011-01-01

    Previous studies have suggested that younger preschoolers exhibit a yes bias due to underdeveloped cognitive abilities, whereas older preschoolers exhibit a response bias due to other factors. To test this hypothesis, we investigated the response latency to yes-no questions pertaining to familiar and unfamiliar objects in 3- to 6-year-olds. The…

  1. Abrupt rise of new machine ecology beyond human response time

    PubMed Central

    Johnson, Neil; Zhao, Guannan; Hunsader, Eric; Qi, Hong; Johnson, Nicholas; Meng, Jing; Tivnan, Brian

    2013-01-01

    Society's techno-social systems are becoming ever faster and more computer-orientated. However, far from simply generating faster versions of existing behaviour, we show that this speed-up can generate a new behavioural regime as humans lose the ability to intervene in real time. Analyzing millisecond-scale data for the world's largest and most powerful techno-social system, the global financial market, we uncover an abrupt transition to a new all-machine phase characterized by large numbers of subsecond extreme events. The proliferation of these subsecond events shows an intriguing correlation with the onset of the system-wide financial collapse in 2008. Our findings are consistent with an emerging ecology of competitive machines featuring ‘crowds' of predatory algorithms, and highlight the need for a new scientific theory of subsecond financial phenomena. PMID:24022120

  2. Method for reducing response time in sensor measurement.

    PubMed

    Casas, Oscar; Rillo, Francesc I

    2009-08-01

    Transients are present in sensor and instrumentation systems. They are caused by energy transference and are typically modeled as first-order systems. If too long, transients may suppose a critical factor for these systems unless they are analyzed (e.g., in terms of consumption). This work presents a new method for estimating the final value of a first-order system transient. Since this problem may be harmful, mainly to autonomous systems, the method equations are composed of simple operations that can be implemented on microcontrollers or similar interfaces with low computational capacity. The experimental results validate the theoretical models of the method and prove that, when the system coexists with disturbances, it is possible to estimate the final value in around 60% of the time we would have to wait until reaching it, in the worst case scenario. PMID:19725676

  3. An FPGA-based frequency response analyzer for multisine and stepped sine measurements on stationary and time-varying impedance

    NASA Astrophysics Data System (ADS)

    Sanchez, B.; Fernandez, X.; Reig, S.; Bragos, R.

    2014-01-01

    We report the development of a field programmable gate array (FPGA) based frequency response analyzer (FRA) for impedance frequency response function (FRF) measurements using periodic excitations, i.e. sine waves and multisines. The stepped sine measurement uses two dedicated hardware-built digital embedded multiplier blocks to extract the phase and quadrature components of the output signal. The multisine FRF measurements compute the fast Fourier transform (FFT) of the input/output signals. In this paper, we describe its design, implementation and performance evaluation, performing electrical impedance spectroscopy (EIS) measurements on phantoms. The stepped sine accuracy is 1.21% at 1 kΩ (1%), the precision is 35 mΩ and the total harmonic distortion plus noise (THD+N) is -120 dB. As for the multisine impedance FRF measurements, the magnitude and phase precision are, respectively, 0.23 Ω at 48.828 kHz and 0.021 deg at 8.087 MHz when measuring a resistor 505 Ω (1%). The magnitude accuracy is 0.55% at 8.087 MHz while the phase accuracy is 0.17 deg at 6.54 MHz. In all, the stepped sine signal-to-noise ratio (SNR) is 84 dB and 65 dB at frequencies below and above 1 MHz respectively. The SNR for the multisine FRF measurements is above 65 dB (30 kHz-10 MHz). The FRA bandwidth is 610.4 mHz-12.5 MHz and the maximum FRF measurement rate exciting with multisines starting at 30 kHz is 200 spectra s-1. Based on its technical specifications and versatility, the FRA presented can be used in many applications, e.g. for getting insight quickly into the instantaneous impedance FRF of the time-varying impedance under test.

  4. Linking impulse response functions to reaction time: Rod and cone reaction time data and a computational model

    PubMed Central

    Cao, Dingcai; Zele, Andrew J.; Pokorny, Joel

    2007-01-01

    Reaction times for incremental and decremental stimuli were measured at five suprathreshold contrasts for six retinal illuminance levels where rods alone (0.002–0.2 Trolands), rods and cones (2–20 Trolands) or cones alone (200 Trolands) mediated detection. A 4-primary photostimulator allowed independent control of rod or cone excitations. This is the first report of reaction times to isolated rod or cone stimuli at mesopic light levels under the same adaptation conditions. The main findings are: 1) For rods, responses to decrements were faster than increments, but cone reaction times were closely similar. 2) At light levels where both systems were functional, rod reaction times were ~20 ms longer. The data were fitted with a computational model that incorporates rod and cone impulse response functions and a stimulus-dependent neural sensory component that triggers a motor response. Rod and cone impulse response functions were derived from published psychophysical two-pulse threshold data and temporal modulation transfer functions. The model fits were accomplished with a limited number of free parameters: two global parameters to estimate the irreducible minimum reaction time for each receptor type, and one local parameter for each reaction time versus contrast function. This is the first model to provide a neural basis for the variation in reaction time with retinal illuminance, stimulus contrast, stimulus polarity, and receptor class modulated. PMID:17346763

  5. Nonparametric Bayesian time-series modeling and clustering of time-domain ground penetrating radar landmine responses

    NASA Astrophysics Data System (ADS)

    Morton, Kenneth D., Jr.; Torrione, Peter A.; Collins, Leslie

    2010-04-01

    Time domain ground penetrating radar (GPR) has been shown to be a powerful sensing phenomenology for detecting buried objects such as landmines. Landmine detection with GPR data typically utilizes a feature-based pattern classification algorithm to discriminate buried landmines from other sub-surface objects. In high-fidelity GPR, the time-frequency characteristics of a landmine response should be indicative of the physical construction and material composition of the landmine and could therefore be useful for discrimination from other non-threatening sub-surface objects. In this research we propose modeling landmine time-domain responses with a nonparametric Bayesian time-series model and we perform clustering of these time-series models with a hierarchical nonparametric Bayesian model. Each time-series is modeled as a hidden Markov model (HMM) with autoregressive (AR) state densities. The proposed nonparametric Bayesian prior allows for automated learning of the number of states in the HMM as well as the AR order within each state density. This creates a flexible time-series model with complexity determined by the data. Furthermore, a hierarchical non-parametric Bayesian prior is used to group landmine responses with similar HMM model parameters, thus learning the number of distinct landmine response models within a data set. Model inference is accomplished using a fast variational mean field approximation that can be implemented for on-line learning.

  6. Reaction Time and Movement Time as Measures of Stimulus Evaluation and Response Processes.

    ERIC Educational Resources Information Center

    Houlihan, Michael; And Others

    1994-01-01

    Three studies involving 16 college students explored cognitive processes reflected by reaction time (RT) and movement time (MT). The hypothesis that correlations of RT and MT with measures of intelligence are due to effects on a common stage of information processing cannot be rejected on the basis of study findings. (SLD)

  7. Time Work by Overworked Professionals: Strategies in Response to the Stress of Higher Status.

    PubMed

    Moen, Phyllis; Lam, Jack; Ammons, Samantha; Kelly, Erin L

    2013-05-01

    How are professionals responding to the time strains brought on by the stress of their higher status jobs? Qualitative data from professionals reveal (a) general acceptance of the emerging temporal organization of professional work, including rising time demands and blurred boundaries around work/ nonwork times and places, and (b) time work as strategic responses to work intensification, overloads, and boundarylessness. We detected four time-work strategies: prioritizing time, scaling back obligations, blocking out time, and time shifting of obligations. These strategies are often more work-friendly than family-friendly, but "blocking out time" and "time shifting" suggest promising avenues for work-time policy and practice. PMID:24039337

  8. Where the ocean influences the impulse response and its effect on synchronous changes of acoustic travel time.

    PubMed

    Spiesberger, John L

    2011-12-01

    In 1983, sounds at 133 Hz, 0.06 s resolution were transmitted in the Pacific for five days at 2 min intervals over 3709 km between bottom-mounted instruments maintained with atomic clocks. In 1989, a technique was developed to measure changes in acoustic travel time with an accuracy of 135 microseconds at 2 min intervals for selected windows of travel time within the impulse response. The data have short-lived 1 to 10 ms oscillations of travel time with periods less than a few days. Excluding tidal effects, different windows exhibited significant synchronized changes in travel time for periods shorter than 10 h. In the 1980s, this phenomenon was not understood because internal waves have correlation lengths of a few kilometers which are smaller than the way sound was thought to sample the ocean along well-separated and distinct rays corresponding to different windows. The paradox's resolution comes from modern theories that replace the ray-picture with finite wavelength representations that predict sound can be influenced in the upper ocean over horizontal scales such as 20 km or more. Thus, different windows are influenced by the same short-scale fluctuations of sound speed. This conclusion is supported by the data and numerical simulations of the impulse response. PMID:22225021

  9. Fast multigrid fluorescent ion chamber with 0.1 ms time response.

    PubMed

    Suzuki, Motohiro; Kawamura, Naomi; Lytle, Farrel W; Ishikawa, Tetsuya

    2002-03-01

    A fast multigrid ion chamber for the detection of fluorescent X-rays has been developed. The structure of 17 grids with close separation was employed to maximize the time response as well as to give sufficient detection efficiency. The measured rise/fall response time to cyclic X-rays was shorter than that of an existing three-grid ion chamber by more than one order of magnitude. A 0.13 ms time response was obtained at the 500 V applied voltage, where the detector can stably operate without any discharge. The available frequency range is as high as 1 kHz with a practical amplitude response. PMID:11872931

  10. Response time of mean square slope to wind forcing: An empirical investigation

    NASA Astrophysics Data System (ADS)

    Chen, David D.; Ruf, Christopher S.; Gleason, Scott T.

    2016-04-01

    We present an empirical study of the response time of surface wave mean square slope to local wind forcing using data collected over 11 years by 46 discus buoys moored at a wide variety of locations. The response time is defined as the time lag at which the time dependence of the waves exhibits the highest correlation with that of the local wind speed. The response time at each location is found to be fairly stable, with the time varying between 0.4 and 1.8 h depending on the location. Examination of long-term statistics reveals response time dependencies on wind speed magnitude, fetch, atmospheric stability, and wavelength. With the increasing reliance on satellite microwave remote sensing as a source of wind data, these results provide useful insights and bounds for their use.

  11. 75 FR 79961 - Temporary Suspension of Certain Oil Spill Response Time Requirements To Support Deepwater Horizon...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-21

    ... Gulf of Mexico Deepwater Horizon SONSat the FOSC's request. 75 FR 37712. The rule also confirmed that...; 2050-AG63 Temporary Suspension of Certain Oil Spill Response Time Requirements To Support Deepwater.... Oil Spill Response Resources Return Time Several comments noted concerns about the return of assets...

  12. The Simplest Complete Model of Choice Response Time: Linear Ballistic Accumulation

    ERIC Educational Resources Information Center

    Brown, Scott D.; Heathcote, Andrew

    2008-01-01

    We propose a linear ballistic accumulator (LBA) model of decision making and reaction time. The LBA is simpler than other models of choice response time, with independent accumulators that race towards a common response threshold. Activity in the accumulators increases in a linear and deterministic manner. The simplicity of the model allows…

  13. A Mixture Proportional Hazards Model with Random Effects for Response Times in Tests

    ERIC Educational Resources Information Center

    Ranger, Jochen; Kuhn, Jörg-Tobias

    2016-01-01

    In this article, a new model for test response times is proposed that combines latent class analysis and the proportional hazards model with random effects in a similar vein as the mixture factor model. The model assumes the existence of different latent classes. In each latent class, the response times are distributed according to a…

  14. Children with autism spectrum disorders show abnormal conditioned response timing on delay, but not trace, eyeblink conditioning

    PubMed Central

    Oristaglio, Jeff; West, Susan Hyman; Ghaffari, Manely; Lech, Melissa S.; Verma, Beeta R.; Harvey, John A.; Welsh, John P.; Malone, Richard P.

    2013-01-01

    Children with autism spectrum disorder (ASD) and age-matched typically-developing (TD) peers were tested on two forms of eyeblink conditioning (EBC), a Pavlovian associative learning paradigm where subjects learn to execute an appropriately-timed eyeblink in response to a previously neutral conditioning stimulus (CS). One version of the task, trace EBC, interposes a stimulus-free interval between the presentation of the CS and the unconditioned stimulus (US), a puff of air to the eye which causes subjects to blink. In delay EBC, the CS overlaps in time with the delivery of the US, usually with both stimuli terminating simultaneously. ASD children performed normally during trace EBC, exhibiting no differences from typically-developing (TD) subjects with regard to learning rate or the timing of the CR. However, when subsequently tested on delay EBC, subjects with ASD displayed abnormally-timed conditioned eye blinks that began earlier and peaked sooner than those of TD subjects, consistent with previous findings. The results suggest an impaired ability of children with ASD to properly time conditioned eye blinks which appears to be specific to delay EBC. We suggest that this deficit may reflect a dysfunction of cerebellar cortex in which increases in the intensity or duration of sensory input can temporarily disrupt the accuracy of motor timing over short temporal intervals. PMID:23769889

  15. First passage time: Connecting random walks to functional responses in heterogeneous environments (Invited)

    NASA Astrophysics Data System (ADS)

    Lewis, M. A.; McKenzie, H.; Merrill, E.

    2010-12-01

    In this talk I will outline first passage time analysis for animals undertaking complex movement patterns, and will demonstrate how first passage time can be used to derive functional responses in predator prey systems. The result is a new approach to understanding type III functional responses based on a random walk model. I will extend the analysis to heterogeneous environments to assess the effects of linear features on functional responses in wolves and elk using GPS tracking data.

  16. Stable measures of number sense accuracy in math learning disability: Is it time to proceed from basic science to clinical application?

    PubMed

    Júlio-Costa, Annelise; Starling-Alves, Isabella; Lopes-Silva, Júlia Beatriz; Wood, Guilherme; Haase, Vitor Geraldi

    2015-12-01

    Math learning disability (MLD) or developmental dyscalculia is a highly prevalent and persistent difficulty in learning arithmetic that may be explained by different cognitive mechanisms. The accuracy of the number sense has been implicated by some evidence as a core deficit in MLD. However, research on this topic has been mainly conducted in demographically selected samples, using arbitrary cut-off scores to characterize MLD. The clinical relevance of the association between number sense and MLD remains to be investigated. In this study, we aimed at assessing the stability of a number sense accuracy measure (w) across five experimental sessions, in two clinically defined cases of MLD. Stable measures of number sense accuracy estimate are required to clinically characterize subtypes of MLD and to make theoretical inferences regarding the underlying cognitive mechanisms. G. A. was a 10-year-old boy with MLD in the context of dyslexia and phonological processing impairment and his performance remained steadily in the typical scores range. The performance of H. V., a 9-year-old girl with MLD associated with number sense inaccuracy, remained consistently impaired across measurements, with a nonsignificant tendency to worsen. Qualitatively, H. V.'s performance was also characterized by greater variability across sessions. Concomitant clinical observations suggested that H. V.'s difficulties could be aggravated by developing symptoms of mathematics anxiety. Results in these two cases are in line with the hypotheses that at least two reliable patterns of cognitive impairment may underlie math learning difficulties in MLD, one related to number sense inaccuracy and the other to phonological processing impairment. Additionally, it indicates the need for more translational research in order to examine the usefulness and validity of theoretical advances in numerical cognition to the clinical neuropsychological practice with MLD. PMID:26459122

  17. Performing dynamic time history analyses by extension of the response spectrum method

    SciTech Connect

    Hulbert, G.M.

    1983-01-01

    A method is presented to calculate the dynamic time history response of finite-element models using results from response spectrum analyses. The proposed modified time history method does not represent a new mathamatical approach to dynamic analysis but suggests a more efficient ordering of the analytical equations and procedures. The modified time history method is considerably faster and less expensive to use than normal time hisory methods. This paper presents the theory and implementation of the modified time history approach along with comparisons of the modified and normal time history methods for a prototypic seismic piping design problem.

  18. Emotional Responses during Reading: Physiological Responses Predict Real-Time Reading Comprehension

    ERIC Educational Resources Information Center

    Daley, Samantha G.; Willett, John B.; Fischer, Kurt W.

    2014-01-01

    This study investigated the relationship between emotional responses and reading performance in middle-school students. Although a large number of prior studies have investigated the relationship between emotion and reading, those studies have concentrated primarily on relatively static and distal measures of emotion. In this research, we measured…

  19. Effect of prolonged bedrest and plus Gz acceleration on peripheral visual response time

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1973-01-01

    Peripheral visual response time changes during +G sub z acceleration following fourteen days of bedrest are considered as well as what effect prolonged bedrest has upon this response. Eighteen test lights, placed 10 deg are apart along the horizontal meridian of the subject's field of view, were presented in a random sequence. The subject was instructed to press a button as soon as a light appeared. Response time testing occurred periodically during bedrest and continuously during centrifugation testing. The results indicate that: (1) mean response time is significantly longer to stimuli imaged in the far periphery than to stimuli imaged closer to the line of sight; (2) mean response time at each stimulus position tends to be longer at plateau g than during the preacceleration baseline period; (3) mean response time tends to lengthen as the g level is increased; (4) peripheral visual response time during +G sub x acceleration at 2, 3.2, and 3.8 g was not a reliable advanced indicator that blackout was going to occur; and (5) the subject's field of view collapsed rapidly just before blackout. Bedrest data showed that the distribution of response times to stimuli imaged across the subject's horizontal retinal meridian remained remarkably constant from day to day during both the bedrest and recovery periods.

  20. Response Times for Correct and Incorrect Item Responses on Computerized Adaptive Tests

    ERIC Educational Resources Information Center

    Chang, Shu-Ren; Plake, Barbara S.; Ferdous, Abdullah A.

    2005-01-01

    This study examined the time different ability level examinees spend taking a CAT on demanding items to these examinees. It was also found that high able examinees spend more time on the pretest items, which are not tailored to the examinees' ability level, than do lower ability examinees. Higher able examinees showed persistence with test…