WorldWideScience

Sample records for individual model performance

  1. Individualized Biomathematical Modeling of Fatigue and Performance

    Science.gov (United States)

    2008-05-29

    Interactions and Transitions 53 New Discoveries , Inventions, or Patent Disclosures 56 FA9550-06-1-0055 Individualized Biomathematical Modeling of Fatigue...Old Dominion University, not supported on grant) Daniel J. Mollicone, Ph.D. ( Pulsar Informatics, Inc., not supported on grant) Christopher G...Mott, M.S. ( Pulsar Informatics, Inc., not supported on grant) Erik Olofsen, M.S. (Leiden University, the Netherlands, not supported on grant

  2. Real-time individualization of the unified model of performance.

    Science.gov (United States)

    Liu, Jianbo; Ramakrishnan, Sridhar; Laxminarayan, Srinivas; Balkin, Thomas J; Reifman, Jaques

    2017-12-01

    Existing mathematical models for predicting neurobehavioural performance are not suited for mobile computing platforms because they cannot adapt model parameters automatically in real time to reflect individual differences in the effects of sleep loss. We used an extended Kalman filter to develop a computationally efficient algorithm that continually adapts the parameters of the recently developed Unified Model of Performance (UMP) to an individual. The algorithm accomplishes this in real time as new performance data for the individual become available. We assessed the algorithm's performance by simulating real-time model individualization for 18 subjects subjected to 64 h of total sleep deprivation (TSD) and 7 days of chronic sleep restriction (CSR) with 3 h of time in bed per night, using psychomotor vigilance task (PVT) data collected every 2 h during wakefulness. This UMP individualization process produced parameter estimates that progressively approached the solution produced by a post-hoc fitting of model parameters using all data. The minimum number of PVT measurements needed to individualize the model parameters depended upon the type of sleep-loss challenge, with ~30 required for TSD and ~70 for CSR. However, model individualization depended upon the overall duration of data collection, yielding increasingly accurate model parameters with greater number of days. Interestingly, reducing the PVT sampling frequency by a factor of two did not notably hamper model individualization. The proposed algorithm facilitates real-time learning of an individual's trait-like responses to sleep loss and enables the development of individualized performance prediction models for use in a mobile computing platform. © 2017 European Sleep Research Society.

  3. Individualized Next-Generation Biomathematical Modeling of Fatigue and Performance

    National Research Council Canada - National Science Library

    Van Dongen, Hans P

    2006-01-01

    .... This project employed a cutting-edge technique called Bayesian forecasting to develop a novel biomathematical performance model to predict responses to sleep loss and circadian displacement for individual subjects...

  4. ASSESSING INDIVIDUAL PERFORMANCE ON INFORMATION TECHNOLOGY ADOPTION: A NEW MODEL

    OpenAIRE

    Diah Hari Suryaningrum

    2012-01-01

    This paper aims to propose a new model in assessing individual performance on information technology adoption. The new model to assess individual performance was derived from two different theories: decomposed theory of planned behavior and task-technology fit theory. Although many researchers have tried to expand these theories, some of their efforts might lack of theoretical assumptions. To overcome this problem and enhance the coherence of the integration, I used a theory from social scien...

  5. CLRP: Individual evaluation of model performance for scenario S

    International Nuclear Information System (INIS)

    Krajewski, P.

    1996-01-01

    The model CLRP was created in 1989 as a part of research project ''Long-Lived Post-Chernobyl Radioactivity and Radiation Protection Criteria for Risk Reduction'' performed in cooperation with US Environmental Protection Agency. The aim of this project was to examine the fate of long-lived radionuclides in the terrestrial ecosystem. Concentrations of Cs-137 and Cs-134 in the particular components of terrestrial ecosystem e.g. soil, vegetation, animal tissues and animal products are calculated as a function of time following deposition from the atmosphere. Based on this data the whole body contents of radionuclide as a function of time is calculated and dose to a specific organ for the radionuclide may be estimated as an integral of the resultant dose rate over a sufficient period. In addition, the model allows estimation of inhalation dose from time integrated air concentration and external dose from total deposition using simple conversion factors. The program is designed to allow the simulation of many different radiological situations (chronic or acute releases) and dose affecting countermeasures. Figs, tabs

  6. TERNIRBU: Description of model and individual evaluation of model performance for scenario S

    International Nuclear Information System (INIS)

    Kanyar, B.; Fueloep, N.

    1996-01-01

    The compartmental model used is realized as a procedure of the general purpose code TAMDYN for simulation, sensitivity and uncertainty calculations of dynamic models. More details of the model structure and parameters are given in the description of the VAMP MP Scenario CB. The difference between the climate in Finland and Central Bohemia was taken into consideration by shifting the seasonality function with 12 days' according to the weekly average temperature. The lake system and the contamination of fishes was simulated by the model SIRATEC used and validated in the BIOMOVS Scenario A5. The model was extended to two fish-compartments for roach and pike ones as a catanary system. For simulations the code TAMDYN was used. The doses were estimated from the time integrated concentrations of the proper components multiplied by the dose conversion factor. 4 figs

  7. Antecedents and Consequences of Individual Performance Analysis of Turnover Intention Model (Empirical Study of Public Accountants in Indonesia)

    OpenAIRE

    Raza, Hendra; Maksum, Azhar; Erlina; Lumban Raja, Prihatin

    2014-01-01

    Azhar Maksum This study aims to examine empirically the antecedents of individual performance on its consequences of turnover intention in public accounting firms. There are eight variables measured which consists of auditors' empowerment, innovation professionalism, role ambiguity, role conflict, organizational commitment, individual performance and turnover intention. Data analysis is based on 163 public accountant using the Structural Equation Modeling assisted with an appli...

  8. A comprehensive model for diagnosing the causes of individual medical performance problems: skills, knowledge, internal, past and external factors (SKIPE).

    Science.gov (United States)

    Norfolk, Tim; Siriwardena, A Niroshan

    2013-01-01

    This discussion paper describes a new and comprehensive model for diagnosing the causes of individual medical performance problems: SKIPE (skills, knowledge, internal, past and external factors). This builds on a previous paper describing a unifying theory of clinical practice, the RDM-p model, which captures the primary skill sets required for effective medical performance (relationship, diagnostics and management), and the professionalism that needs to underpin them. The SKIPE model is currently being used, in conjunction with the RDM-p model, for the in-depth assessment and management of doctors whose performance is a cause for concern.

  9. The role of individualism and the Five-Factor Model in the prediction of performance in a leaderless group discussion.

    Science.gov (United States)

    Waldman, David A; Atwater, Leanne E; Davidson, Ronald A

    2004-02-01

    Personality has seen a resurgence in the work performance literature. The Five-Factor Model (FFM) represents a set of personality factors that has received the most attention in recent years. Despite its popularity, the FFM may not be sufficiently comprehensive to account for relevant variation across performance dimensions or tasks. Accordingly, the present study also considers how individualism may predict additional variance in performance beyond the FFM. The study involved 152 undergraduate students who experienced a leaderless group discussion (LGD) exercise. Results showed that while the FFM accounted for variance in students' LGD performance, individualism (independence) accounted for additional, unique variance. Furthermore, analyses of the group compositions revealed curvilinear relationships between the relative amount of extraversion, conscientiousness, and individualism in relation to group-level performance.

  10. MODEL OF EMERGENCY DEPARTMENT NURSE PERFORMANCE IMPROVEMENT BASED ON ASSOCIATION OF INDIVIDUAL CHARACTERISTIC, ORGANIZATION CHARACTERISTIC AND JOB CHARACTERISTIC

    Directory of Open Access Journals (Sweden)

    Maria Margaretha Bogar

    2017-04-01

    Full Text Available Introduction: Nursing care is integral part of health care and having important role in management of patient with emergency condition. The purpose of this research was to develop nurse performance improvement model based on individual, organization and job characteristics association in Emergency Department of RSUD dr TC Hillers Maumere. Method: This was an explanative survey by cross sectional approach held on July -August 2012. Respondents in this study were 22 nurses and 44 patients were obtained by purposive sampling technique. Data were analyzed by partial least square test and signi fi cant t value > 1.64 (alpha 10%. Result: Results showed that individual characteristic had effect on nurse performance (t = 7.59, organization characteristic had effect on nurse performance (t = 2.03 and job characteristic didn’t have effect on nurse performance (t = 0.88. Nurse performance had effect on patient satisfaction (t = 6.54 but nurse satisfaction didn’t have effect on nurse performance (t = 1.31, and nurse satisfaction didn’t have effect either on patient satisfaction (t = 0.94. Discussion: This research concluded that individual characteristics which in fl uence nurse performance in nursing care were ability and skill, experience, age, sex, attitude and motivation. Organization characteristic that influence nurse performance was reward while job characteristic that include job design and feedback didn’t influence nurse performance in nursing care. Nurse performance influenced patient satisfaction but nurse satisfaction didn’t influence patient satisfaction and nurse performance.

  11. Modeling the Direct and Indirect Determinants of Different Types of Individual Job Performance

    National Research Council Canada - National Science Library

    Johnson, Jeff W; Duehr, Emily E; Hezlett, Sarah A; Muros, John P; Ferstl, Kerri L

    2008-01-01

    Despite the importance of citizenship performance and adaptive performance to Army junior commissioned officer job performance, there has been very little published research studying these constructs...

  12. The Impact of Individual Differences, Types of Model and Social Settings on Block Building Performance among Chinese Preschoolers

    Directory of Open Access Journals (Sweden)

    Mi Tian

    2018-01-01

    Full Text Available Children’s block building performances are used as indicators of other abilities in multiple domains. In the current study, we examined individual differences, types of model and social settings as influences on children’s block building performance. Chinese preschoolers (N = 180 participated in a block building activity in a natural setting, and performance was assessed with multiple measures in order to identify a range of specific skills. Using scores generated across these measures, three dependent variables were analyzed: block building skills, structural balance and structural features. An overall MANOVA showed that there were significant main effects of gender and grade level across most measures. Types of model showed no significant effect in children’s block building. There was a significant main effect of social settings on structural features, with the best performance in the 5-member group, followed by individual and then the 10-member block building. These findings suggest that boys performed better than girls in block building activity. Block building performance increased significantly from 1st to 2nd year of preschool, but not from second to third. The preschoolers created more representational constructions when presented with a model made of wooden rather than with a picture. There was partial evidence that children performed better when working with peers in a small group than when working alone or working in a large group. It is suggested that future study should examine other modalities rather than the visual one, diversify the samples and adopt a longitudinal investigation.

  13. The Impact of Individual Differences, Types of Model and Social Settings on Block Building Performance among Chinese Preschoolers.

    Science.gov (United States)

    Tian, Mi; Deng, Zhu; Meng, Zhaokun; Li, Rui; Zhang, Zhiyi; Qi, Wenhui; Wang, Rui; Yin, Tingting; Ji, Menghui

    2018-01-01

    Children's block building performances are used as indicators of other abilities in multiple domains. In the current study, we examined individual differences, types of model and social settings as influences on children's block building performance. Chinese preschoolers ( N = 180) participated in a block building activity in a natural setting, and performance was assessed with multiple measures in order to identify a range of specific skills. Using scores generated across these measures, three dependent variables were analyzed: block building skills, structural balance and structural features. An overall MANOVA showed that there were significant main effects of gender and grade level across most measures. Types of model showed no significant effect in children's block building. There was a significant main effect of social settings on structural features, with the best performance in the 5-member group, followed by individual and then the 10-member block building. These findings suggest that boys performed better than girls in block building activity. Block building performance increased significantly from 1st to 2nd year of preschool, but not from second to third. The preschoolers created more representational constructions when presented with a model made of wooden rather than with a picture. There was partial evidence that children performed better when working with peers in a small group than when working alone or working in a large group. It is suggested that future study should examine other modalities rather than the visual one, diversify the samples and adopt a longitudinal investigation.

  14. Model Of Emergency Department Nurse Performance Improvement Based on Association of Individual Characteristic, Organization Characteristic and Job Characteristic

    OpenAIRE

    Bogar, Maria Margaretha; Nursalam, Nursalam; Dewi, Yulis Setiya

    2017-01-01

    Introduction: Nursing care is integral part of health care and having important role in management of patient with emergency condition. The purpose of this research was to develop nurse performance improvement model based on individual, organization and job characteristics association in Emergency Department of RSUD dr TC Hillers Maumere. Method: This was an explanative survey by cross sectional approach held on July -August 2012. Respondents in this study were 22 nurses and 44 patients were ...

  15. Blending Individual and Group Assessment: A Model for Measuring Student Performance

    Science.gov (United States)

    Reiser, Elana

    2017-01-01

    Two sections of a college discrete mathematics class were taught using cooperative learning techniques throughout the semester. The 33 students attending these sections were randomly assigned into groups of three. Their final examination consisted of an individual and group blended examination where students worked in their groups and discussed…

  16. Modeling the Direct and Indirect Determinants of Different Types of Individual Job Performance

    Science.gov (United States)

    2008-06-01

    dimension is an element of task performance (Johnson, 2003), the middle three dimensions all tap different aspects of citizenship performance (Borman...Record your effectiveness rating for each response (from 1 to 7) on the line to the eft of the response. In addition, select which ONE response out of

  17. Mechanistic Physiologically Based Pharmacokinetic (PBPK) Model of the Heart Accounting for Inter-Individual Variability: Development and Performance Verification.

    Science.gov (United States)

    Tylutki, Zofia; Mendyk, Aleksander; Polak, Sebastian

    2018-04-01

    Modern model-based approaches to cardiac safety and efficacy assessment require accurate drug concentration-effect relationship establishment. Thus, knowledge of the active concentration of drugs in heart tissue is desirable along with inter-subject variability influence estimation. To that end, we developed a mechanistic physiologically based pharmacokinetic model of the heart. The models were described with literature-derived parameters and written in R, v.3.4.0. Five parameters were estimated. The model was fitted to amitriptyline and nortriptyline concentrations after an intravenous infusion of amitriptyline. The cardiac model consisted of 5 compartments representing the pericardial fluid, heart extracellular water, and epicardial intracellular, midmyocardial intracellular, and endocardial intracellular fluids. Drug cardiac metabolism, passive diffusion, active efflux, and uptake were included in the model as mechanisms involved in the drug disposition within the heart. The model accounted for inter-individual variability. The estimates of optimized parameters were within physiological ranges. The model performance was verified by simulating 5 clinical studies of amitriptyline intravenous infusion, and the simulated pharmacokinetic profiles agreed with clinical data. The results support the model feasibility. The proposed structure can be tested with the goal of improving the patient-specific model-based cardiac safety assessment and offers a framework for predicting cardiac concentrations of various xenobiotics. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  18. An Examination of Individual Performance Using Markov Models in the Hellenic Navy’s Officer-Performance Evaluation System

    Science.gov (United States)

    2012-03-01

    similar to primary needs, but now emotions have replaced transmitted signals. In the 1940s, Maslow developed the needs-hierarchy theory. 37...is the specific design to meet new challenges and realize our potential. McShane and Von Glinow state that …according to Maslow , we are...circumstances, individuals seek their constant personal development. In addition to Abraham Maslow’s needs-hierarchy theory, a recently developed

  19. Impact of high-performance work systems on individual- and branch-level performance: test of a multilevel model of intermediate linkages.

    Science.gov (United States)

    Aryee, Samuel; Walumbwa, Fred O; Seidu, Emmanuel Y M; Otaye, Lilian E

    2012-03-01

    We proposed and tested a multilevel model, underpinned by empowerment theory, that examines the processes linking high-performance work systems (HPWS) and performance outcomes at the individual and organizational levels of analyses. Data were obtained from 37 branches of 2 banking institutions in Ghana. Results of hierarchical regression analysis revealed that branch-level HPWS relates to empowerment climate. Additionally, results of hierarchical linear modeling that examined the hypothesized cross-level relationships revealed 3 salient findings. First, experienced HPWS and empowerment climate partially mediate the influence of branch-level HPWS on psychological empowerment. Second, psychological empowerment partially mediates the influence of empowerment climate and experienced HPWS on service performance. Third, service orientation moderates the psychological empowerment-service performance relationship such that the relationship is stronger for those high rather than low in service orientation. Last, ordinary least squares regression results revealed that branch-level HPWS influences branch-level market performance through cross-level and individual-level influences on service performance that emerges at the branch level as aggregated service performance.

  20. Perceiving individuality in harpsichord performance.

    Science.gov (United States)

    Koren, Réka; Gingras, Bruno

    2014-01-01

    Can listeners recognize the individual characteristics of unfamiliar performers playing two different musical pieces on the harpsichord? Six professional harpsichordists, three prize-winners and three non prize-winners, made two recordings of two pieces from the Baroque period (a variation on a Partita by Frescobaldi and a rondo by François Couperin) on an instrument equipped with a MIDI console. Short (8 to 15 s) excerpts from these 24 recordings were subsequently used in a sorting task in which 20 musicians and 20 non-musicians, balanced for gender, listened to these excerpts and grouped together those that they thought had been played by the same performer. Twenty-six participants, including 17 musicians and nine non-musicians, performed significantly better than chance, demonstrating that the excerpts contained sufficient information to enable listeners to recognize the individual characteristics of the performers. The grouping accuracy of musicians was significantly higher than that observed for non-musicians. No significant difference in grouping accuracy was found between prize-winning performers and non-winners or between genders. However, the grouping accuracy was significantly higher for the rondo than for the variation, suggesting that the features of the two pieces differed in a way that affected the listeners' ability to sort them accurately. Furthermore, only musicians performed above chance level when matching variation excerpts with rondo excerpts, suggesting that accurately assigning recordings of different pieces to their performer may require musical training. Comparisons between the MIDI performance data and the results of the sorting task revealed that tempo and, to a lesser extent, note onset asynchrony were the most important predictors of the perceived distance between performers, and that listeners appeared to rely mostly on a holistic percept of the excerpts rather than on a comparison of note-by-note expressive patterns.

  1. Perceiving individuality in harpsichord performance

    Directory of Open Access Journals (Sweden)

    Réka eKoren

    2014-02-01

    Full Text Available Can listeners recognize the individual characteristics of unfamiliar performers playing two different musical pieces on the harpsichord? Six professional harpsichordists, three prize-winners and three non prize-winners, made two recordings of two pieces from the Baroque period (a variation on a partita by Frescobaldi and a rondo by François Couperin on an instrument equipped with a MIDI console. Short (8 to 15 seconds excerpts from these 24 recordings were subsequently used in a sorting task in which twenty musicians and twenty non-musicians, balanced for gender, listened to these excerpts and grouped together those that they thought had been played by the same performer. Twenty-six participants, including 17 musicians and 9 non-musicians, performed significantly better than chance, demonstrating that the excerpts contained sufficient information to enable listeners to recognize the individual characteristics of the performers. The grouping accuracy of musicians was significantly higher than that observed for non‐musicians. No significant difference in grouping accuracy was found between prize-winning performers and non-winners or between genders. However, the grouping accuracy was significantly higher for the rondo than for the variation, suggesting that the features of the two pieces differed in a way that affected the listeners’ ability to sort them accurately. Furthermore, only musicians performed above chance level when matching variation excerpts with rondo excerpts, suggesting that accurately assigning recordings of different pieces to their performer may require musical training. Comparisons between the MIDI performance data and the results of the sorting task revealed that tempo and, to a lesser extent, note onset asynchrony were the most important predictors of the perceived distance between performers, and that listeners appeared to rely mostly on a holistic percept of the excerpts rather than on a comparison of note

  2. Perceiving individuality in harpsichord performance

    Science.gov (United States)

    Koren, Réka; Gingras, Bruno

    2014-01-01

    Can listeners recognize the individual characteristics of unfamiliar performers playing two different musical pieces on the harpsichord? Six professional harpsichordists, three prize-winners and three non prize-winners, made two recordings of two pieces from the Baroque period (a variation on a Partita by Frescobaldi and a rondo by François Couperin) on an instrument equipped with a MIDI console. Short (8 to 15 s) excerpts from these 24 recordings were subsequently used in a sorting task in which 20 musicians and 20 non-musicians, balanced for gender, listened to these excerpts and grouped together those that they thought had been played by the same performer. Twenty-six participants, including 17 musicians and nine non-musicians, performed significantly better than chance, demonstrating that the excerpts contained sufficient information to enable listeners to recognize the individual characteristics of the performers. The grouping accuracy of musicians was significantly higher than that observed for non-musicians. No significant difference in grouping accuracy was found between prize-winning performers and non-winners or between genders. However, the grouping accuracy was significantly higher for the rondo than for the variation, suggesting that the features of the two pieces differed in a way that affected the listeners’ ability to sort them accurately. Furthermore, only musicians performed above chance level when matching variation excerpts with rondo excerpts, suggesting that accurately assigning recordings of different pieces to their performer may require musical training. Comparisons between the MIDI performance data and the results of the sorting task revealed that tempo and, to a lesser extent, note onset asynchrony were the most important predictors of the perceived distance between performers, and that listeners appeared to rely mostly on a holistic percept of the excerpts rather than on a comparison of note-by-note expressive patterns. PMID:24605104

  3. IASM: Individualized activity space modeler

    Science.gov (United States)

    Hasanzadeh, Kamyar

    2018-01-01

    Researchers from various disciplines have long been interested in analyzing and describing human mobility patterns. Activity space (AS), defined as an area encapsulating daily human mobility and activities, has been at the center of this interest. However, given the applied nature of research in this field and the complexity that advanced geographical modeling can pose to its users, the proposed models remain simplistic and inaccurate in many cases. Individualized Activity Space Modeler (IASM) is a geographic information system (GIS) toolbox, written in Python programming language using ESRI's Arcpy module, comprising four tools aiming to facilitate the use of advanced activity space models in empirical research. IASM provides individual-based and context-sensitive tools to estimate home range distances, delineate activity spaces, and model place exposures using individualized geographical data. In this paper, we describe the design and functionality of IASM, and provide an example of how it performs on a spatial dataset collected through an online map-based survey.

  4. Deriving estimates of individual variability in genetic potentials of performance traits for 3 dairy breeds, using a model of lifetime nutrient partitioning

    DEFF Research Database (Denmark)

    Phuong, H N; Martin, O; de Boer, I J M

    2015-01-01

    , body reserve usage, and growth for different genotypes of cow. Moreover, it can be used to separate genetic variability in performance between individual cows from environmental noise. The model enables simulation of the effects of a genetic selection strategy on lifetime efficiency of individual cows......, which has a main advantage of including the rearing costs, and thus, can be used to explore the impact of future selection on animal performance and efficiency....

  5. Responsiveness of the individual work performance questionnaire.

    NARCIS (Netherlands)

    Koopmans, L.; Coffeng, J.K.; Bernaards, C.M.; Boot, C.R.L.; Hildebrandt, V.H.; Vet, H.C.W. de; Beek, A.J. van der

    2014-01-01

    Background: Individual work performance is an important outcome measure in studies in the workplace. Nevertheless, its conceptualization and measurement has proven challenging. To overcome limitations of existing scales, the Individual Work Performance Questionnaire (IWPQ) was recently developed.

  6. Responsiveness of the individual work performance questionnaire

    NARCIS (Netherlands)

    Koopmans, L.; Coffeng, J.K.; Bernaards, C.M.; Boot, C.R.; Hildebrandt, V.H.; Vet, H.C. de; Beek, A.J. van der

    2014-01-01

    Background: Individual work performance is an important outcome measure in studies in the workplace. Nevertheless, its conceptualization and measurement has proven challenging. To overcome limitations of existing scales, the Individual Work Performance Questionnaire (IWPQ) was recently developed.

  7. Do Dual-Route Models Accurately Predict Reading and Spelling Performance in Individuals with Acquired Alexia and Agraphia?

    OpenAIRE

    Rapcsak, Steven Z.; Henry, Maya L.; Teague, Sommer L.; Carnahan, Susan D.; Beeson, Pélagie M.

    2007-01-01

    Coltheart and colleagues (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001; Castles, Bates, & Coltheart, 2006) have demonstrated that an equation derived from dual-route theory accurately predicts reading performance in young normal readers and in children with reading impairment due to developmental dyslexia or stroke. In this paper we present evidence that the dual-route equation and a related multiple regression model also accurately predict both reading and spelling performance in adult...

  8. Development of an Individual Work Performance Questionnaire

    NARCIS (Netherlands)

    Koopmans, L.; Bernaards, C.M.; Hildebrandt, V.H.; van Buuren, S.; van der Beek, A.J.; de Vet, H.C.W.

    2013-01-01

    The purpose of the current study is to develop a generic and short questionnaire to measure work performance at the individual level – the Individual Work Performance Questionnaire (IWPQ). The IWPQ was based on a four-dimensional conceptual framework, in which individual work performance consisted

  9. Optimization of biomathematical model predictions for cognitive performance impairment in individuals: accounting for unknown traits and uncertain states in homeostatic and circadian processes.

    Science.gov (United States)

    Van Dongen, Hans P A; Mott, Christopher G; Huang, Jen-Kuang; Mollicone, Daniel J; McKenzie, Frederic D; Dinges, David F

    2007-09-01

    Current biomathematical models of fatigue and performance do not accurately predict cognitive performance for individuals with a priori unknown degrees of trait vulnerability to sleep loss, do not predict performance reliably when initial conditions are uncertain, and do not yield statistically valid estimates of prediction accuracy. These limitations diminish their usefulness for predicting the performance of individuals in operational environments. To overcome these 3 limitations, a novel modeling approach was developed, based on the expansion of a statistical technique called Bayesian forecasting. The expanded Bayesian forecasting procedure was implemented in the two-process model of sleep regulation, which has been used to predict performance on the basis of the combination of a sleep homeostatic process and a circadian process. Employing the two-process model with the Bayesian forecasting procedure to predict performance for individual subjects in the face of unknown traits and uncertain states entailed subject-specific optimization of 3 trait parameters (homeostatic build-up rate, circadian amplitude, and basal performance level) and 2 initial state parameters (initial homeostatic state and circadian phase angle). Prior information about the distribution of the trait parameters in the population at large was extracted from psychomotor vigilance test (PVT) performance measurements in 10 subjects who had participated in a laboratory experiment with 88 h of total sleep deprivation. The PVT performance data of 3 additional subjects in this experiment were set aside beforehand for use in prospective computer simulations. The simulations involved updating the subject-specific model parameters every time the next performance measurement became available, and then predicting performance 24 h ahead. Comparison of the predictions to the subjects' actual data revealed that as more data became available for the individuals at hand, the performance predictions became

  10. Do dual-route models accurately predict reading and spelling performance in individuals with acquired alexia and agraphia?

    Science.gov (United States)

    Rapcsak, Steven Z; Henry, Maya L; Teague, Sommer L; Carnahan, Susan D; Beeson, Pélagie M

    2007-06-18

    Coltheart and co-workers [Castles, A., Bates, T. C., & Coltheart, M. (2006). John Marshall and the developmental dyslexias. Aphasiology, 20, 871-892; Coltheart, M., Rastle, K., Perry, C., Langdon, R., & Ziegler, J. (2001). DRC: A dual route cascaded model of visual word recognition and reading aloud. Psychological Review, 108, 204-256] have demonstrated that an equation derived from dual-route theory accurately predicts reading performance in young normal readers and in children with reading impairment due to developmental dyslexia or stroke. In this paper, we present evidence that the dual-route equation and a related multiple regression model also accurately predict both reading and spelling performance in adult neurological patients with acquired alexia and agraphia. These findings provide empirical support for dual-route theories of written language processing.

  11. Responsiveness of the individual work performance questionnaire

    OpenAIRE

    Koopmans, Linda; Coffeng, Jennifer K; Bernaards, Claire M; Boot, Cécile RL; Hildebrandt, Vincent H; de Vet, Henrica CW; van der Beek, Allard J

    2014-01-01

    Background: Individual work performance is an important outcome measure in studies in the workplace. Nevertheless, its conceptualization and measurement has proven challenging. To overcome limitations of existing scales, the Individual Work Performance Questionnaire (IWPQ) was recently developed. The aim of the current study was to gain insight into the responsiveness of the IWPQ. Methods. Data were used from the Be Active & Relax randomized controlled trial. The aim of the trial was to inves...

  12. Verification of Temperature and Precipitation Simulated Data by Individual and Ensemble Performance of Five AOGCM Models for North East of Iran

    Directory of Open Access Journals (Sweden)

    B. Ashraf

    2014-08-01

    Full Text Available Scince climatic models are the basic tools to study climate change and because of the multiplicity of these models, selecting the most appropriate model for the studying location is very considerable. In this research the temperature and precipitation simulated data by BCM2, CGCM3, CNRMCM3, MRICGCM2.3 and MIROC3 models are downscaled with proportional method according A1B, A2 and B1 emission scenarios for Torbat-heydariye, Sabzevar and Mashhad initially. Then using coefficient of determination (R2, index of agreement (D and mean-square deviations (MSD, models were verified individually and as ensemble performance. The results showed that, based on individual performance and three emission scenarios, MRICGCM2.3 model in Torbat-heydariye and Mashhad and MIROC3.2 model in Sabzevar had the best performance in simulation of temperature and MIROC3.2, MRICGCM2.3 and CNRMCM3 models have provided the most accurate predictions for precipitation in Torbat-heydariye, Sabzevar and Mashahad respectively. Also simulated temperature by all models in Torbat-heydariye and Sabzevar base on B1 scenario and, in Mashhad based on A2 scenario had the lowest uncertainty. The most accuracy in modeling of precipitation was resulted based on A2 scenario in Torbat-heydariye and, B1 scenario in Sabzevar and Mashhad. Investigation of calculated statistics driven from ensemble performance of 5 selected models caused notable reduction of simulation error and thus increase the accuracy of predictions based on all emission scenarios generally. In this case, the best fitting of simulated and observed temperature data were achieved based on B1 scenario in Torbat-heydariye and Sabzevar and, A2 scenario in Mashhad. And the best fitting simulated and observed precipitation data were obtained based on A2 scenario in Torbat-heydariye and, B1 scenario in Sabzevar and Mashhad. According to the results of this research, before any climate change research it is necessary to select the

  13. Individual model evaluation and probabilistic weighting of models

    International Nuclear Information System (INIS)

    Atwood, C.L.

    1994-01-01

    This note stresses the importance of trying to assess the accuracy of each model individually. Putting a Bayesian probability distribution on a population of models faces conceptual and practical complications, and apparently can come only after the work of evaluating the individual models. Moreover, the primary issue is open-quotes How good is this modelclose quotes? Therefore, the individual evaluations are first in both chronology and importance. They are not easy, but some ideas are given here on how to perform them

  14. Option trading and individual investor performance

    NARCIS (Netherlands)

    Bauer, R.; Cosemans, M.; Eichholtz, P.

    2009-01-01

    This paper examines the impact of option trading on individual investor performance. The results show that most investors incur substantial losses on their option investments, which are much larger than the losses from equity trading. We attribute the detrimental impact of option trading on investor

  15. Responsiveness of the individual work performance questionnaire

    Science.gov (United States)

    2014-01-01

    Background Individual work performance is an important outcome measure in studies in the workplace. Nevertheless, its conceptualization and measurement has proven challenging. To overcome limitations of existing scales, the Individual Work Performance Questionnaire (IWPQ) was recently developed. The aim of the current study was to gain insight into the responsiveness of the IWPQ. Methods Data were used from the Be Active & Relax randomized controlled trial. The aim of the trial was to investigate the effectiveness of an intervention to stimulate physical activity and relaxation of office workers, on need for recovery. Individual work performance was a secondary outcome measure of the trial. In total, 39 hypotheses were formulated concerning correlations between changes on the IWPQ scales and changes on similar constructs (e.g., presenteeism) and distinct constructs (e.g., need for recovery) used in the trial. Results 260 Participants completed the IWPQ at both baseline and 12 months of follow-up. For the IWPQ scales, 23%, 15%, and 38%, respectively, of the hypotheses could be confirmed. In general, the correlations between change scores were weaker than expected. Nevertheless, at least 85% of the correlations were in the expected direction. Conclusions Based on results of the current study, no firm conclusions can be drawn about the responsiveness of the IWPQ. Several reasons may account for the weaker than expected correlations. Future research on the IWPQ’s responsiveness should be conducted, preferably in other populations and intervention studies, where greater changes over time can be expected. PMID:24885593

  16. Statistical characteristics of aberrations of human eyes after small incision lenticule extraction surgery and analysis of visual performance with individual eye model.

    Science.gov (United States)

    Lou, Qiqi; Wang, Yan; Wang, Zhaoqi; Liu, Yongji; Zhang, Lin; Fang, Hui

    2015-09-01

    Preoperative and postoperative wavefront aberrations of 73 myopic eyes with small incision lenticule extraction surgery are analyzed in this paper. Twenty-eight postoperative individual eye models are constructed to investigate the visual acuity (VA) of human eyes. Results show that in photopic condition, residual defocus, residual astigmatism, and higher-order aberrations are relatively small. 100% of eyes reach a VA of 0.8 or better, and 89.3% of eyes reach a VA of 1.0 or better. In scotopic condition, the residual defocus and the higher-order aberrations are, respectively, 1.9 and 8.5 times the amount of that in photopic condition, and the defocus becomes the main factor attenuating visual performance.

  17. Modeling Individual Cyclic Variation in Human Behavior.

    Science.gov (United States)

    Pierson, Emma; Althoff, Tim; Leskovec, Jure

    2018-04-01

    Cycles are fundamental to human health and behavior. Examples include mood cycles, circadian rhythms, and the menstrual cycle. However, modeling cycles in time series data is challenging because in most cases the cycles are not labeled or directly observed and need to be inferred from multidimensional measurements taken over time. Here, we present Cyclic Hidden Markov Models (CyH-MMs) for detecting and modeling cycles in a collection of multidimensional heterogeneous time series data. In contrast to previous cycle modeling methods, CyHMMs deal with a number of challenges encountered in modeling real-world cycles: they can model multivariate data with both discrete and continuous dimensions; they explicitly model and are robust to missing data; and they can share information across individuals to accommodate variation both within and between individual time series. Experiments on synthetic and real-world health-tracking data demonstrate that CyHMMs infer cycle lengths more accurately than existing methods, with 58% lower error on simulated data and 63% lower error on real-world data compared to the best-performing baseline. CyHMMs can also perform functions which baselines cannot: they can model the progression of individual features/symptoms over the course of the cycle, identify the most variable features, and cluster individual time series into groups with distinct characteristics. Applying CyHMMs to two real-world health-tracking datasets-of human menstrual cycle symptoms and physical activity tracking data-yields important insights including which symptoms to expect at each point during the cycle. We also find that people fall into several groups with distinct cycle patterns, and that these groups differ along dimensions not provided to the model. For example, by modeling missing data in the menstrual cycles dataset, we are able to discover a medically relevant group of birth control users even though information on birth control is not given to the model.

  18. Financial Advice and Individual Investor Portfolio Performance

    NARCIS (Netherlands)

    Kramer, M.M.

    2012-01-01

    This paper investigates whether financial advisers add value to individual investors portfolio decisions by comparing portfolios of advised and self-directed (execution-only) Dutch individual investors. The results indicate significant differences in characteristics and portfolios between these

  19. Modelling individual difference in visual categorization.

    Science.gov (United States)

    Shen, Jianhong; Palmeri, Thomas J

    Recent years has seen growing interest in understanding, characterizing, and explaining individual differences in visual cognition. We focus here on individual differences in visual categorization. Categorization is the fundamental visual ability to group different objects together as the same kind of thing. Research on visual categorization and category learning has been significantly informed by computational modeling, so our review will focus both on how formal models of visual categorization have captured individual differences and how individual difference have informed the development of formal models. We first examine the potential sources of individual differences in leading models of visual categorization, providing a brief review of a range of different models. We then describe several examples of how computational models have captured individual differences in visual categorization. This review also provides a bit of an historical perspective, starting with models that predicted no individual differences, to those that captured group differences, to those that predict true individual differences, and to more recent hierarchical approaches that can simultaneously capture both group and individual differences in visual categorization. Via this selective review, we see how considerations of individual differences can lead to important theoretical insights into how people visually categorize objects in the world around them. We also consider new directions for work examining individual differences in visual categorization.

  20. Conceptual frameworks of individual work performance: A systematic review

    NARCIS (Netherlands)

    Koopmans, L.; Bernaards, C.M.; Hildebrandt, V.H.; Schaufeli, W.B.; Vet, H.C.W. de; Beek, A.J. van der

    2011-01-01

    Objective: Individual work performance is differently conceptualized and operationalized in different disciplines. The aim of the current review was twofold: (1) identifying conceptual frameworks of individual work performance and (2) integrating these to reach a heuristic conceptual framework.

  1. Conceptual frameworks of individual work performance a systematic review

    NARCIS (Netherlands)

    Koopmans, L.; Bernaards, C.M.; Hildebrandt, V.H.; Schaufeli, W.B.; de Vet, H.C.W.; van der Beek, A.J.

    2011-01-01

    Objective: Individual work performance is differently conceptualized and operationalized in different disciplines. The aim of the current review was twofold: (1) identifying conceptual frameworks of individual work performance and (2) integrating these to reach a heuristic conceptual framework.

  2. Measuring individual work performance: Identifying and selecting indicators

    NARCIS (Netherlands)

    Koopmans, L.; Bernaards, C.M.; Hildebrandt, V.H.; de Vet, H.C.W.; van der Beek, A.J.

    2014-01-01

    BACKGROUND: Theoretically, individual work performance (IWP) can be divided into four dimensions: task performance, contextual performance, adaptive performance, and counterproductive work behavior. However, there is no consensus on the indicators used to measure these dimensions.

  3. Measuring individual work performance: identifying and selecting indicators

    NARCIS (Netherlands)

    Koopmans, L.; Bernaards, C.M.; Hildebrandt, V.H.; Vet, H.C de; Beek, A.J. van der

    2014-01-01

    BACKGROUND: Theoretically, individual work performance (IWP) can be divided into four dimensions: task performance, contextual performance, adaptive performance, and counterproductive work behavior. However, there is no consensus on the indicators used to measure these dimensions. OBJECTIVE: This

  4. How does a servant leader fuel the service fire? A multilevel model of servant leadership, individual self identity, group competition climate, and customer service performance.

    Science.gov (United States)

    Chen, Zhijun; Zhu, Jing; Zhou, Mingjian

    2015-03-01

    Building on a social identity framework, our cross-level process model explains how a manager's servant leadership affects frontline employees' service performance, measured as service quality, customer-focused citizenship behavior, and customer-oriented prosocial behavior. Among a sample of 238 hairstylists in 30 salons and 470 of their customers, we found that hair stylists' self-identity embedded in the group, namely, self-efficacy and group identification, partially mediated the positive effect of salon managers' servant leadership on stylists' service performance as rated by the customers, after taking into account the positive influence of transformational leadership. Moreover, group competition climate strengthened the positive relationship between self-efficacy and service performance. PsycINFO Database Record (c) 2015 APA, all rights reserved.

  5. Bivalves: From individual to population modelling

    NARCIS (Netherlands)

    Saraiva, S.; van der Meer, J.; Kooijman, S.A.L.M.

    2014-01-01

    An individual based population model for bivalves was designed, built and tested in a 0D approach, to simulate the population dynamics of a mussel bed located in an intertidal area. The processes at the individual level were simulated following the dynamic energy budget theory, whereas initial egg

  6. Individual Hearing Loss: Characterization, Modelling, Compensation Strategies

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten; Christensen-Dalsgaard, Jakob

    2016-01-01

    account for such individual differences, which make it challenging to find adequate compensation strategies in hearing devices. How to characterize, model, and compensate for individual hearing loss were the main topics of the fifth International Symposium on Auditory and Audiological Research (ISAAR...

  7. Individual Performance Management: A Review of Current Practices

    Directory of Open Access Journals (Sweden)

    Ian O’ Boyle

    2013-05-01

    Full Text Available This paper provides a review of current practice in relation to individual performance management systems and process within the traditional business environment. There is a consensus that the role of the individual is central to the overall performance of any organization and how individual performances are managed and evaluated can have significant impacts on overall organizational success. Many organizations employ the traditional performance appraisal in order to monitor and assess individual employee performances. However, new approaches, such as 360-degree feedback have also become commonplace within the business environment. An analysis of each approach including benefits and challenges associated with each process is presented within this paper.

  8. Improving the Individual Work Performance Questionnaire using Rasch analysis.

    OpenAIRE

    Koopmans, L.; Bernaards, C.M.; Hildebrandt, V.H.; Buuren, S. van; Beek, A.J. van der; Vet, H.C.W. de

    2014-01-01

    Recently, the Individual Work Performance Questionnaire (IWPQ) version 0.2 was developed using Rasch analysis. The goal of the current study was to improve targeting of the IWPQ scales by including additional items. The IWPQ 0.2 (original) and 0.3 (including additional items) were examined using Rasch analysis. Additional items that showed misfit or did not improve targeting were removed from the IWPQ 0.3, resulting in a final IWPQ 1.0. Subsequently, the scales showed good model fit and relia...

  9. Bivalves: From individual to population modelling

    Science.gov (United States)

    Saraiva, S.; van der Meer, J.; Kooijman, S. A. L. M.; Ruardij, P.

    2014-11-01

    An individual based population model for bivalves was designed, built and tested in a 0D approach, to simulate the population dynamics of a mussel bed located in an intertidal area. The processes at the individual level were simulated following the dynamic energy budget theory, whereas initial egg mortality, background mortality, food competition, and predation (including cannibalism) were additional population processes. Model properties were studied through the analysis of theoretical scenarios and by simulation of different mortality parameter combinations in a realistic setup, imposing environmental measurements. Realistic criteria were applied to narrow down the possible combination of parameter values. Field observations obtained in the long-term and multi-station monitoring program were compared with the model scenarios. The realistically selected modeling scenarios were able to reproduce reasonably the timing of some peaks in the individual abundances in the mussel bed and its size distribution but the number of individuals was not well predicted. The results suggest that the mortality in the early life stages (egg and larvae) plays an important role in population dynamics, either by initial egg mortality, larvae dispersion, settlement failure or shrimp predation. Future steps include the coupling of the population model with a hydrodynamic and biogeochemical model to improve the simulation of egg/larvae dispersion, settlement probability, food transport and also to simulate the feedback of the organisms' activity on the water column properties, which will result in an improvement of the food quantity and quality characterization.

  10. DEVELOPING OF INDIVIDUAL INSTRUMENT PERFORMANCE ANXIETY SCALE: VALIDITY - RELIABILITY STUDY

    Directory of Open Access Journals (Sweden)

    Esra DALKIRAN

    2014-07-01

    Full Text Available The purpose of this study is to develop a scale unique to our culture, concerning  individual instrument performance anxiety of the students  who are getting instrument training  in the Department of Music Education. In the study, the descriptive research model is used and qualitative research techniques are utilized. The study population consists of the students attending the 23 universities which has Music Education Department. The sample of the study consists of 438 girls and 312 boys, totally 750 students  who are studying in the Department of Music Education of randomly selected 10 universities. As a result of the explanatory and confirmatory factor analyses that were performed, a one-dimensional structure consisting of 14 items was obtained. Also, t-scores and  the coefficient scores of total item correlation concerning the distinguishing power of the items, the difference in the scores of the set of lower and upper 27% was calculated, and it was observed that the items are distinguishing as a result of both analyses. Of the scale, Cronbach's alpha coefficient of internal consistency was calculated as .94, and test-retest reliability coefficient was calculated as .93. As a result, a valid and reliable assessment and evaluation instrument that measures the exam performance anxiety of the students studying in the Department of Music Education, has been developed.Extended AbstractsIntroductionAnxiety is a universal phenomenon which people experience once or a few times during lives. It was accepted as concern for the future or as an unpleasant emotional experience regarding probable hitches of the events (Di Tomasso & Gosch, 2002.In general, the occasions on which negative feelings are experienced cause anxiety to arise (Baltaş and Baltaş, 2000. People also feel anxious in dangerous situations. Anxiety may lead a person to be creative, while it may have hindering characteristics. Anxiety is that an individual considers him

  11. Well performance model

    International Nuclear Information System (INIS)

    Thomas, L.K.; Evans, C.E.; Pierson, R.G.; Scott, S.L.

    1992-01-01

    This paper describes the development and application of a comprehensive oil or gas well performance model. The model contains six distinct sections: stimulation design, tubing and/or casing flow, reservoir and near-wellbore calculations, production forecasting, wellbore heat transmission, and economics. These calculations may be performed separately or in an integrated fashion with data and results shared among the different sections. The model analysis allows evaluation of all aspects of well completion design, including the effects on future production and overall well economics

  12. Investigating Individual Differences in Toddler Search with Mixture Models

    Science.gov (United States)

    Berthier, Neil E.; Boucher, Kelsea; Weisner, Nina

    2015-01-01

    Children's performance on cognitive tasks is often described in categorical terms in that a child is described as either passing or failing a test, or knowing or not knowing some concept. We used binomial mixture models to determine whether individual children could be classified as passing or failing two search tasks, the DeLoache model room…

  13. Individualized performance prediction during total sleep deprivation: accounting for trait vulnerability to sleep loss.

    Science.gov (United States)

    Ramakrishnan, Sridhar; Laxminarayan, Srinivas; Thorsley, David; Wesensten, Nancy J; Balkin, Thomas J; Reifman, Jaques

    2012-01-01

    Individual differences in vulnerability to sleep loss can be considerable, and thus, recent efforts have focused on developing individualized models for predicting the effects of sleep loss on performance. Individualized models constructed using a Bayesian formulation, which combines an individual's available performance data with a priori performance predictions from a group-average model, typically need at least 40 h of individual data before showing significant improvement over the group-average model predictions. Here, we improve upon the basic Bayesian formulation for developing individualized models by observing that individuals may be classified into three sleep-loss phenotypes: resilient, average, and vulnerable. For each phenotype, we developed a phenotype-specific group-average model and used these models to identify each individual's phenotype. We then used the phenotype-specific models within the Bayesian formulation to make individualized predictions. Results on psychomotor vigilance test data from 48 individuals indicated that, on average, ∼85% of individual phenotypes were accurately identified within 30 h of wakefulness. The percentage improvement of the proposed approach in 10-h-ahead predictions was 16% for resilient subjects and 6% for vulnerable subjects. The trade-off for these improvements was a slight decrease in prediction accuracy for average subjects.

  14. Cross-cultural adaptation of the Individual Work Performance Questionnaire

    NARCIS (Netherlands)

    Koopmans, L.; Bernaards, C.M.; Hildebrandt, V.H.; Lerner, D.; Vet, H.C.W. de; Beek, A.J. van der

    2016-01-01

    BACKGROUND: The Individual Work Performance Questionnaire (IWPQ), measuring task performance, contextual performance, and counterproductive work behavior, was developed in The Netherlands. OBJECTIVES: To cross-culturally adapt the IWPQ from the Dutch to the American-English language, and assess the

  15. Career Development, Collective Efficacy, and Individual Task Performance

    Science.gov (United States)

    Kellett, Janet B.; Humphrey, Ronald H.; Sleeth, Randall G.

    2009-01-01

    Purpose: The purpose of this paper is to test the hypothesis that perceived collective efficacy would mediate the effects of self-efficacy on individual task performance. Design/methodology/approach: An assessment center design with 147 participants in 49 three-person groups was used. Findings: It is found that for individuals working on an…

  16. NIF capsule performance modeling

    Directory of Open Access Journals (Sweden)

    Weber S.

    2013-11-01

    Full Text Available Post-shot modeling of NIF capsule implosions was performed in order to validate our physical and numerical models. Cryogenic layered target implosions and experiments with surrogate targets produce an abundance of capsule performance data including implosion velocity, remaining ablator mass, times of peak x-ray and neutron emission, core image size, core symmetry, neutron yield, and x-ray spectra. We have attempted to match the integrated data set with capsule-only simulations by adjusting the drive and other physics parameters within expected uncertainties. The simulations include interface roughness, time-dependent symmetry, and a model of mix. We were able to match many of the measured performance parameters for a selection of shots.

  17. INDIVIDUAL BASED MODELLING APPROACH TO THERMAL ...

    Science.gov (United States)

    Diadromous fish populations in the Pacific Northwest face challenges along their migratory routes from declining habitat quality, harvest, and barriers to longitudinal connectivity. Changes in river temperature regimes are producing an additional challenge for upstream migrating adult salmon and steelhead, species that are sensitive to absolute and cumulative thermal exposure. Adult salmon populations have been shown to utilize cold water patches along migration routes when mainstem river temperatures exceed thermal optimums. We are employing an individual based model (IBM) to explore the costs and benefits of spatially-distributed cold water refugia for adult migrating salmon. Our model, developed in the HexSim platform, is built around a mechanistic behavioral decision tree that drives individual interactions with their spatially explicit simulated environment. Population-scale responses to dynamic thermal regimes, coupled with other stressors such as disease and harvest, become emergent properties of the spatial IBM. Other model outputs include arrival times, species-specific survival rates, body energetic content, and reproductive fitness levels. Here, we discuss the challenges associated with parameterizing an individual based model of salmon and steelhead in a section of the Columbia River. Many rivers and streams in the Pacific Northwest are currently listed as impaired under the Clean Water Act as a result of high summer water temperatures. Adverse effec

  18. Ion thruster performance model

    International Nuclear Information System (INIS)

    Brophy, J.R.

    1984-01-01

    A model of ion thruster performance is developed for high flux density cusped magnetic field thruster designs. This model is formulated in terms of the average energy required to produce an ion in the discharge chamber plasma and the fraction of these ions that are extracted to form the beam. The direct loss of high energy (primary) electrons from the plasma to the anode is shown to have a major effect on thruster performance. The model provides simple algebraic equations enabling one to calculate the beam ion energy cost, the average discharge chamber plasma ion energy cost, the primary electron density, the primary-to-Maxwellian electron density ratio and the Maxwellian electron temperature. Experiments indicate that the model correctly predicts the variation in plasma ion energy cost for changes in propellant gas (Ar, Kr, and Xe), grid transparency to neutral atoms, beam extraction area, discharge voltage, and discharge chamber wall temperature

  19. Base Station Performance Model

    OpenAIRE

    Walsh, Barbara; Farrell, Ronan

    2005-01-01

    At present the testing of power amplifiers within base station transmitters is limited to testing at component level as opposed to testing at the system level. While the detection of catastrophic failure is possible, that of performance degradation is not. This paper proposes a base station model with respect to transmitter output power with the aim of introducing system level monitoring of the power amplifier behaviour within the base station. Our model reflects the expe...

  20. Scapular muscle performance in individuals with lateral epicondylalgia.

    Science.gov (United States)

    Day, Joseph M; Bush, Heather; Nitz, Arthur J; Uhl, Tim L

    2015-05-01

    Descriptive, laboratory-based, cross-sectional study. To describe scapular musculature strength, endurance, and change in thickness in individuals with unilateral lateral epicondylalgia (LE) compared to the uninvolved limb and the corresponding limb of a matched comparison group. Reported poor long-term outcomes for the nonsurgical management of individuals with LE suggest a less-than-optimal rehabilitation process. Knowledge of scapular muscle function in a working population of individuals with LE may help to further refine conservative management of this condition. Twenty-eight patients with symptomatic LE and 28 controls matched by age and sex were recruited to participate in the study. Strength of the middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) was measured with a handheld dynamometer. A scapular isometric muscle endurance task was performed in prone. Changes in muscle thickness of the SA and LT were measured with ultrasound imaging. Analysis-of-variance models were used to determine within- and between-group differences. The involved side of the group with LE had significantly lower values for MT strength (P = .031), SA strength (PLE had significantly lower strength of the LT (P = .023) and SA (P = .016) when compared to the uninvolved limb; however, these differences were small and of potentially limited clinical significance. When compared to a matched comparison group, there were impairments of scapular musculature strength and endurance in patients with LE, suggesting that the scapular musculature should be assessed and potentially treated in this population. Cause and effect cannot be established, as the weakness of the scapular musculature could be a result of LE.

  1. Performance modeling of Beamlet

    International Nuclear Information System (INIS)

    Auerbach, J.M.; Lawson, J.K.; Rotter, M.D.; Sacks, R.A.; Van Wonterghem, B.W.; Williams, W.H.

    1995-01-01

    Detailed modeling of beam propagation in Beamlet has been made to predict system performance. New software allows extensive use of optical component characteristics. This inclusion of real optical component characteristics has resulted in close agreement between calculated and measured beam distributions

  2. Monitoring individual and joint action outcomes in duet music performance

    DEFF Research Database (Denmark)

    Loehr, Janeen; Kourtis, Dimitrios; Vesper, Cordula

    2013-01-01

    We investigated whether people monitor the outcomes of their own and their partners’ individual actions as well as the outcome of their combined actions when performing joint actions together. Pairs of pianists memorized both parts of a piano duet. Each pianist then performed one part while their...

  3. ATR performance modeling concepts

    Science.gov (United States)

    Ross, Timothy D.; Baker, Hyatt B.; Nolan, Adam R.; McGinnis, Ryan E.; Paulson, Christopher R.

    2016-05-01

    Performance models are needed for automatic target recognition (ATR) development and use. ATRs consume sensor data and produce decisions about the scene observed. ATR performance models (APMs) on the other hand consume operating conditions (OCs) and produce probabilities about what the ATR will produce. APMs are needed for many modeling roles of many kinds of ATRs (each with different sensing modality and exploitation functionality combinations); moreover, there are different approaches to constructing the APMs. Therefore, although many APMs have been developed, there is rarely one that fits a particular need. Clarified APM concepts may allow us to recognize new uses of existing APMs and identify new APM technologies and components that better support coverage of the needed APMs. The concepts begin with thinking of ATRs as mapping OCs of the real scene (including the sensor data) to reports. An APM is then a mapping from explicit quantized OCs (represented with less resolution than the real OCs) and latent OC distributions to report distributions. The roles of APMs can be distinguished by the explicit OCs they consume. APMs used in simulations consume the true state that the ATR is attempting to report. APMs used online with the exploitation consume the sensor signal and derivatives, such as match scores. APMs used in sensor management consume neither of those, but estimate performance from other OCs. This paper will summarize the major building blocks for APMs, including knowledge sources, OC models, look-up tables, analytical and learned mappings, and tools for signal synthesis and exploitation.

  4. Individual based and mean-field modeling of direct aggregation

    KAUST Repository

    Burger, Martin

    2013-10-01

    We introduce two models of biological aggregation, based on randomly moving particles with individual stochasticity depending on the perceived average population density in their neighborhood. In the firstorder model the location of each individual is subject to a density-dependent random walk, while in the second-order model the density-dependent random walk acts on the velocity variable, together with a density-dependent damping term. The main novelty of our models is that we do not assume any explicit aggregative force acting on the individuals; instead, aggregation is obtained exclusively by reducing the individual stochasticity in response to higher perceived density. We formally derive the corresponding mean-field limits, leading to nonlocal degenerate diffusions. Then, we carry out the mathematical analysis of the first-order model, in particular, we prove the existence of weak solutions and show that it allows for measure-valued steady states. We also perform linear stability analysis and identify conditions for pattern formation. Moreover, we discuss the role of the nonlocality for well-posedness of the first-order model. Finally, we present results of numerical simulations for both the first- and second-order model on the individual-based and continuum levels of description. 2012 Elsevier B.V. All rights reserved.

  5. Individual based and mean-field modeling of direct aggregation

    KAUST Repository

    Burger, Martin; Haskovec, Jan; Wolfram, Marie-Therese

    2013-01-01

    We introduce two models of biological aggregation, based on randomly moving particles with individual stochasticity depending on the perceived average population density in their neighborhood. In the firstorder model the location of each individual is subject to a density-dependent random walk, while in the second-order model the density-dependent random walk acts on the velocity variable, together with a density-dependent damping term. The main novelty of our models is that we do not assume any explicit aggregative force acting on the individuals; instead, aggregation is obtained exclusively by reducing the individual stochasticity in response to higher perceived density. We formally derive the corresponding mean-field limits, leading to nonlocal degenerate diffusions. Then, we carry out the mathematical analysis of the first-order model, in particular, we prove the existence of weak solutions and show that it allows for measure-valued steady states. We also perform linear stability analysis and identify conditions for pattern formation. Moreover, we discuss the role of the nonlocality for well-posedness of the first-order model. Finally, we present results of numerical simulations for both the first- and second-order model on the individual-based and continuum levels of description. 2012 Elsevier B.V. All rights reserved.

  6. Individuality in harpsichord performance: disentangling performer- and piece-specific influences on interpretive choices.

    Science.gov (United States)

    Gingras, Bruno; Asselin, Pierre-Yves; McAdams, Stephen

    2013-01-01

    Although a growing body of research has examined issues related to individuality in music performance, few studies have attempted to quantify markers of individuality that transcend pieces and musical styles. This study aims to identify such meta-markers by discriminating between influences linked to specific pieces or interpretive goals and performer-specific playing styles, using two complementary statistical approaches: linear mixed models (LMMs) to estimate fixed (piece and interpretation) and random (performer) effects, and similarity analyses to compare expressive profiles on a note-by-note basis across pieces and expressive parameters. Twelve professional harpsichordists recorded three pieces representative of the Baroque harpsichord repertoire, including three interpretations of one of these pieces, each emphasizing a different melodic line, on an instrument equipped with a MIDI console. Four expressive parameters were analyzed: articulation, note onset asynchrony, timing, and velocity. LMMs showed that piece-specific influences were much larger for articulation than for other parameters, for which performer-specific effects were predominant, and that piece-specific influences were generally larger than effects associated with interpretive goals. Some performers consistently deviated from the mean values for articulation and velocity across pieces and interpretations, suggesting that global measures of expressivity may in some cases constitute valid markers of artistic individuality. Similarity analyses detected significant associations among the magnitudes of the correlations between the expressive profiles of different performers. These associations were found both when comparing across parameters and within the same piece or interpretation, or on the same parameter and across pieces or interpretations. These findings suggest the existence of expressive meta-strategies that can manifest themselves across pieces, interpretive goals, or expressive devices.

  7. Individuality in harpsichord performance: Disentangling performer- and piece-specific influences on interpretive choices

    Directory of Open Access Journals (Sweden)

    Bruno eGingras

    2013-11-01

    Full Text Available Although a growing body of research has examined issues related to individuality in music performance, few studies have attempted to quantify markers of individuality that transcend pieces and musical styles. This study aims to identify such meta-markers by discriminating between influences linked to specific pieces or interpretive goals and performer-specific playing styles, using two complementary statistical approaches: linear mixed models (LMMs to estimate fixed (piece and interpretation and random (performer effects, and similarity analyses to compare expressive profiles on a note-by-note basis across pieces and expressive parameters. Twelve professional harpsichordists recorded three pieces representative of the Baroque harpsichord repertoire, including three interpretations of one of these pieces, each emphasizing a different melodic line, on an instrument equipped with a MIDI console. Four expressive parameters were analyzed: articulation, note onset asynchrony, timing, and velocity. LMMs showed that piece-specific influences were much larger for articulation than for other parameters, for which performer-specific effects were predominant, and that piece-specific influences were generally larger than effects associated with interpretive goals. Some performers consistently deviated from the mean values for articulation and velocity across pieces and interpretations, suggesting that global measures of expressivity may in some cases constitute valid markers of artistic individuality. Similarity analyses detected significant associations among the magnitudes of the correlations between the expressive profiles of different performers. These associations were found both when comparing across parameters and within the same piece or interpretation, or on the same parameter and across pieces or interpretations. These findings suggest the existence of expressive meta-strategies that can manifest themselves across pieces, interpretive goals, or

  8. The Regression Analysis of Individual Financial Performance: Evidence from Croatia

    OpenAIRE

    Bahovec, Vlasta; Barbić, Dajana; Palić, Irena

    2017-01-01

    Background: A large body of empirical literature indicates that gender and financial literacy are significant determinants of individual financial performance. Objectives: The purpose of this paper is to recognize the impact of the variable financial literacy and the variable gender on the variation of the financial performance using the regression analysis. Methods/Approach: The survey was conducted using the systematically chosen random sample of Croatian financial consumers. The cross sect...

  9. Performance analysis of the TNO TLD individual monitoring service

    International Nuclear Information System (INIS)

    Dijk, J.W.E. van; Julius, H.W.

    1990-01-01

    The purpose of this study was to analyse the performance and to establish the lowest detectable occupational dose (LDOD) of the TNO TL dosemeter, in use for large scale routine individual monitoring since 1983. The TNO individual monitoring service uses three TLD reader systems and over 45000 TL dosemeters, designed to measure H s (0.07) and H p (10). Each reader system is normalised daily and each individual dosemeter is calibrated every ten readout cycles. The performance of the service is monitored by a double blind experimental set-up. A series of 10 routine dosemeters is issued every fortnight, mailed, exposed by staff not involved in the monitoring service, sent back and evaluated. The conclusion of this study is that the lowest detectable occupational dose is less than 0.04 mSv and that the integrated dose at the level of the annual dose limit is measured within 2%. (author)

  10. Culture and individual performance management in University of ...

    African Journals Online (AJOL)

    Their success depends not only on socio-economic and political factors but also on cultural values that influence their activities. In this article, we draw upon the case of one Ghanaian university to illustrate the extent to which cultural values that individuals bring to the workplace pose challenges to performance management ...

  11. Individual Training, Performance Improvement, and the Future for Organizations

    Science.gov (United States)

    Kaufman, Roger

    2015-01-01

    Human competence is a vital element for any organization that expects to survive and then thrive. Developing individual performance ability is necessary but not sufficient because trained people alone will not make an organization successful. We must determine what people should deliver and why it should be delivered in order to add measurable…

  12. Quantifying the performance of individual players in a team activity.

    Science.gov (United States)

    Duch, Jordi; Waitzman, Joshua S; Amaral, Luís A Nunes

    2010-06-16

    Teamwork is a fundamental aspect of many human activities, from business to art and from sports to science. Recent research suggest that team work is of crucial importance to cutting-edge scientific research, but little is known about how teamwork leads to greater creativity. Indeed, for many team activities, it is not even clear how to assign credit to individual team members. Remarkably, at least in the context of sports, there is usually a broad consensus on who are the top performers and on what qualifies as an outstanding performance. In order to determine how individual features can be quantified, and as a test bed for other team-based human activities, we analyze the performance of players in the European Cup 2008 soccer tournament. We develop a network approach that provides a powerful quantification of the contributions of individual players and of overall team performance. We hypothesize that generalizations of our approach could be useful in other contexts where quantification of the contributions of individual team members is important.

  13. Quantifying the performance of individual players in a team activity.

    Directory of Open Access Journals (Sweden)

    Jordi Duch

    2010-06-01

    Full Text Available Teamwork is a fundamental aspect of many human activities, from business to art and from sports to science. Recent research suggest that team work is of crucial importance to cutting-edge scientific research, but little is known about how teamwork leads to greater creativity. Indeed, for many team activities, it is not even clear how to assign credit to individual team members. Remarkably, at least in the context of sports, there is usually a broad consensus on who are the top performers and on what qualifies as an outstanding performance.In order to determine how individual features can be quantified, and as a test bed for other team-based human activities, we analyze the performance of players in the European Cup 2008 soccer tournament. We develop a network approach that provides a powerful quantification of the contributions of individual players and of overall team performance.We hypothesize that generalizations of our approach could be useful in other contexts where quantification of the contributions of individual team members is important.

  14. Vocal performance reflects individual quality in a nonpasserine

    NARCIS (Netherlands)

    Janicke, T.; Hahn, S.M.; Ritz, M.S.; Peter, H.-U.

    2008-01-01

    Recent studies on mate-quality recognition in passerines showed that females use subtle differences in sound production to assess males. We analysed long calls of brown skuas, Catharacta antarctica lonnbergi, to test whether vocal performance could serve as an indicator of individual quality in a

  15. Individual Investor Perceptions, Behavior, and Performance During the Financial Crisis

    NARCIS (Netherlands)

    Hoffmann, A.O.I.; Post, T.; Pennings, J.M.E.

    2011-01-01

    Abstract: We study how during the financial crisis individual investor perceptions change, impact trading and risk-taking behavior, and explain performance. Based on monthly survey data and matching brokerage records from April 2008 to March 2009, we find that successful investors had higher return

  16. Individual Investor Perceptions, Behavior, and Performance During the Financial Crisis

    NARCIS (Netherlands)

    Hoffmann, A.O.I.; Pennings, J.M.E.; Post, T.

    2011-01-01

    We study how during the financial crisis individual investor perceptions change, impact trading and risk-taking behavior, and explain performance. Based on monthly survey data and matching brokerage records from April 2008 to March 2009, we find that successful investors had higher return

  17. Hospital versus individual surgeon’s performance in laparoscopic hysterectomy

    NARCIS (Netherlands)

    Driessen, Sara R C; Wallwiener, Markus; Taran, Florin Andrei; Cohen, Sarah L.; Kraemer, Bernhard; Wallwiener, Christian W.; Van Zwet, Erik W.; Brucker, Sara Y.; Jansen, F.W.

    2017-01-01

    Purpose: To compare hospital versus individual surgeon’s perioperative outcomes for laparoscopic hysterectomy (LH), and to assess the relationship between surgeon experience and perioperative outcomes. Methods: A retrospective analysis of all prospective collected LHs performed from 2003 to 2010

  18. Construct validity of the Individual Work Performance Questionnaire.

    NARCIS (Netherlands)

    Koopmans, L.; Bernaards, C.M.; Hildebrandt, V.H.; Vet, H.C.W. de; Beek, A.J. van der

    2014-01-01

    Objective: To examine the construct validity of the Individual Work Performance Questionnaire (IWPQ). Methods: A total of 1424 Dutch workers from three occupational sectors (blue, pink, and white collar) participated in the study. First, IWPQ scores were correlated with related constructs

  19. Improving the Individual Work Performance Questionnaire using Rasch analysis.

    NARCIS (Netherlands)

    Koopmans, L.; Bernaards, C.M.; Hildebrandt, V.H.; Buuren, S. van; Beek, A.J. van der; Vet, H.C.W. de

    2014-01-01

    Recently, the Individual Work Performance Questionnaire (IWPQ) version 0.2 was developed using Rasch analysis. The goal of the current study was to improve targeting of the IWPQ scales by including additional items. The IWPQ 0.2 (original) and 0.3 (including additional items) were examined using

  20. Construct validity of the individual work performance questionnaire

    NARCIS (Netherlands)

    Koopmans, L.; Bernaards, C.M.; Hildebrandt, V.H.; Vet, H.C.W. de; Beek, A.J. van der

    2014-01-01

    OBJECTIVE:: To examine the construct validity of the Individual Work Performance Questionnaire (IWPQ). METHODS:: A total of 1424 Dutch workers from three occupational sectors (blue, pink, and white collar) participated in the study. First, IWPQ scores were correlated with related constructs

  1. Trajectories and models of individual growth

    Directory of Open Access Journals (Sweden)

    Arseniy Karkach

    2006-11-01

    Full Text Available It has long been recognized that the patterns of growth play an important role in the evolution of age trajectories of fertility and mortality (Williams, 1957. Life history studies would benefit from a better understanding of strategies and mechanisms of growth, but still no comparative research on individual growth strategies has been conducted. Growth patterns and methods have been shaped by evolution and a great variety of them are observed. Two distinct patterns - determinate and indeterminate growth - are of a special interest for these studies since they present qualitatively different outcomes of evolution. We attempt to draw together studies covering growth in plant and animal species across a wide range of phyla focusing primarily on the noted qualitative features. We also review mathematical descriptions of growth, namely empirical growth curves and growth models, and discuss the directions of future research.

  2. Individual Alpha Peak Frequency in Ice Hockey Shooting Performance

    Directory of Open Access Journals (Sweden)

    Sommer Christie

    2017-05-01

    Full Text Available There are several important inter- and intra-individual variations in individual alpha peak frequency (IAPF in the cognitive domain. The rationale for the present study was to extend the research on IAPF in the cognitive domain to IAPF in the sport domain. Specifically, the purpose of the present study was twofold: (a to explore whether baseline IAPF is related to performance in an ice hockey shooting task and (b to explore whether a shooting task has an effect on IAPF variability. The present investigation is one of the first studies to examine links between IAPF and sport performance. Study results did not show significant changes in IAPF when comparing baseline IAPF and pre- to post-task IAPF across three performance levels. The findings support previous literature in the cognitive domain suggesting that IAPF is a stable neurophysiological marker. Future research should consider the following methodological suggestions: (a measuring IAPF during sport performance instead of at a resting state, (b changing the pre-performance resting baseline instructions to take into account sport-specific mental preparation, (c exploring an expert-novice paradigm to accentuate performance ability differences between groups (d comparing tasks with different levels of complexity, and (e analyzing the possible correlation between IAPF and performance on different days.

  3. Individual and team performance in team-handball: a review.

    Science.gov (United States)

    Wagner, Herbert; Finkenzeller, Thomas; Würth, Sabine; von Duvillard, Serge P

    2014-12-01

    Team handball is a complex sport game that is determined by the individual performance of each player as well as tactical components and interaction of the team. The aim of this review was to specify the elements of team-handball performance based on scientific studies and practical experience, and to convey perspectives for practical implication. Scientific studies were identified via data bases of PubMed, Web of Knowledge, SPORT Discus, Google Scholar, and Hercules. A total of 56 articles met the inclusion criteria. In addition, we supplemented the review with 13 additional articles, proceedings and book sections. It was found that the specific characteristics of team-handball with frequent intensity changes, team-handball techniques, hard body confrontations, mental skills and social factors specify the determinants of coordination, endurance, strength and cognition. Although we found comprehensive studies examining individual performance in team-handball players of different experience level, sex or age, there is a lack of studies, particularly for team-handball specific training, as well as cognition and social factors. Key PointsThe specific characteristics of team-handball with frequent intensity changes, specific skills, hard body confrontations, mental skills and social factors define the determinants of coordination, endurance, strength and cognition.To increase individual and team performance in team-handball specific training based on these determinants have been suggested.Although there are comprehensive studies examining individual performance in team-handball players of different experience level, sex, or age are published, there is a lack of training studies, particularly for team-handball specific techniques and endurance, as well as cognition and social factors.

  4. Construct validity of the Individual Work Performance Questionnaire.

    OpenAIRE

    Koopmans, L.; Bernaards, C.M.; Hildebrandt, V.H.; Vet, H.C.W. de; Beek, A.J. van der

    2014-01-01

    Objective: To examine the construct validity of the Individual Work Performance Questionnaire (IWPQ). Methods: A total of 1424 Dutch workers from three occupational sectors (blue, pink, and white collar) participated in the study. First, IWPQ scores were correlated with related constructs (convergent validity). Second, differences between known groups were tested (discriminative validity). Results: First, IWPQ scores correlated weakly to moderately with absolute and relative presenteeism, and...

  5. Effects of Individual Success on Globally Distributed Team Performance

    OpenAIRE

    Yılmaz, Onur

    2013-01-01

    Necessity of different competencies with high level of knowledge makes it inevitable that software development is a team work. With the today's technology, teams can communicate both synchronously and asynchronously using different online collaboration tools throughout the world. Researches indicate that there are many factors that affect the team success and in this paper, effect of individual success on globally distributed team performance will be analyzed. Student team projects undertaken...

  6. Treating individuals with debilitating performance anxiety: An introduction.

    Science.gov (United States)

    Powell, Douglas H

    2004-08-01

    Clinicians often see clients who have debilitating performance anxiety. They suffer from public speaking anxiety, stage fright, test-taking anxiety, and writing block. Their condition is so severe as to threaten to end their academic or professional career. Musicians and athletes also seek help because their anxiety before and during an event causes them to perform at a level well below their demonstrated capabilities. An estimated 2% of the U.S. population is afflicted by debilitating performance anxiety. Effective treatments are now available. This article reviews those behavioral, cognitive, and technological therapies that have shown great promise for treating individuals who have debilitating performance anxiety and introduces this issue of the Journal of Clinical Psychology: In Session devoted to this topic. Copyright 2004 Wiley Periodicals, Inc.

  7. Efeitos de variáveis individuais e contextuais sobre desempenho individual no trabalho Effects of individuals and contextual variables on individual performance at work

    Directory of Open Access Journals (Sweden)

    Francisco Antonio Coelho Junior

    2011-08-01

    Full Text Available O presente trabalho objetivou testar empiricamente um modelo teórico multinível de predição de desempenho individual no trabalho. As variáveis antecedentes investigadas, isoladas ou em interação, corresponderam à idade, gênero, cargo, grau de escolaridade, tempo de serviço e percepção de suporte à aprendizagem, medidas no nível individual e de contexto, e satisfação no trabalho, de nível individual. A pesquisa foi realizada em uma empresa pública, do ramo de pesquisas agropecuária e atuação nacional. A amostra (N = 808 contou com funcionários distribuídos em 45 unidades centralizadas e descentralizadas da empresa pelo Brasil. A coleta de dados foi realizada à distância, via e-mail. Os resultados multiníveis corroboraram o modelo teórico de pesquisa hipotetizado e evidenciaram que a variância de desempenho foi explicada por distintos preditores de nível individual e de contexto, isoladamente ou em interação.This paper aims to empirically test a theoretical multilevel model for the prediction of individual performance at work. Antecedent variables, isolated or in interaction, were age, gender, function, scholarity, period of function and perception of learning support, in the individual and contextual levels, and satisfaction at work, an individual variable. This study was accomplished in a public corporation which deals with agricultural research in a national scope. The participants (N = 808 were distribute in 45 central and noncentral units for the Brazil. Data collection was done online, by e-mail. The multilevel results confirm the hypothetic theoretical model and make evident that the performance's variance were predicted by different individuals and context variables, isolated or in interaction.

  8. Anticipatory synergy adjustments reflect individual performance of feedforward force control.

    Science.gov (United States)

    Togo, Shunta; Imamizu, Hiroshi

    2016-10-06

    We grasp and dexterously manipulate an object through multi-digit synergy. In the framework of the uncontrolled manifold (UCM) hypothesis, multi-digit synergy is defined as the coordinated control mechanism of fingers to stabilize variable important for task success, e.g., total force. Previous studies reported anticipatory synergy adjustments (ASAs) that correspond to a drop of the synergy index before a quick change of the total force. The present study compared ASA's properties with individual performances of feedforward force control to investigate a relationship of those. Subjects performed a total finger force production task that consisted of a phase in which subjects tracked target line with visual information and a phase in which subjects produced total force pulse without visual information. We quantified their multi-digit synergy through UCM analysis and observed significant ASAs before producing total force pulse. The time of the ASA initiation and the magnitude of the drop of the synergy index were significantly correlated with the error of force pulse, but not with the tracking error. Almost all subjects showed a significant increase of the variance that affected the total force. Our study directly showed that ASA reflects the individual performance of feedforward force control independently of target-tracking performance and suggests that the multi-digit synergy was weakened to adjust the multi-digit movements based on a prediction error so as to reduce the future error. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Measuring individual work performance: identifying and selecting indicators.

    Science.gov (United States)

    Koopmans, Linda; Bernaards, Claire M; Hildebrandt, Vincent H; de Vet, Henrica C W; van der Beek, Allard J

    2014-01-01

    Theoretically, individual work performance (IWP) can be divided into four dimensions: task performance, contextual performance, adaptive performance, and counterproductive work behavior. However, there is no consensus on the indicators used to measure these dimensions. This study was designed to (1) identify indicators for each dimension, (2) select the most relevant indicators, and (3) determine the relative weight of each dimension in ratings of work performance. IWP indicators were identified from multiple research disciplines, via literature, existing questionnaires, and expert interviews. Subsequently, experts selected the most relevant indicators per dimension and scored the relative weight of each dimension in ratings of IWP. In total, 128 unique indicators were identified. Twenty-three of these indicators were selected by experts as most relevant for measuring IWP. Task performance determined 36% of the work performance rating, while the other three dimensions respectively determined 22%, 20% and 21% of the rating. Notable consensus was found on relevant indicators of IWP, reducing the number from 128 to 23 relevant indicators. This provides an important step towards the development of a standardized, generic and short measurement instrument for assessing IWP.

  10. Predicting Performance during Chronic Sleep Loss: Identification of Factors Sensitive to Individual Fatigue Resistance

    Science.gov (United States)

    2015-03-18

    fatigue-related performance impairments for a given schedule. However, these models fail to account for individual differences in fatigue susceptibility...Tool, FAST ™ ), yet these models fail to take into account important individual differences in fatigue states and susceptibility to fatigue. However...Venkatraman et al., 2007) and confusion ( Drury et al., 2012). However, sustained or continuous operations in high tempo, wartime operations often

  11. Disclosure of Individual Surgeon's Performance Rates During Informed Consent

    Science.gov (United States)

    Burger, Ingrid; Schill, Kathryn; Goodman, Steven

    2007-01-01

    Objective: The purpose of the paper is to examine the ethical arguments for and against disclosing surgeon-specific performance rates to patients during informed consent, and to examine the challenges that generating and using performance rates entail. Methods: Ethical, legal, and statistical theory is explored to approach the question of whether, when, and how surgeons should disclosure their personal performance rates to patients. The main ethical question addressed is what type of information surgeons owe their patients during informed consent. This question comprises 3 related, ethically relevant considerations that are explored in detail: 1) Does surgeon-specific performance information enhance patient decision-making? 2) Do patients want this type of information? 3) How do the potential benefits of disclosure balance against the risks? Results: Calculating individual performance measures requires tradeoffs and involves inherent uncertainty. There is a lack of evidence regarding whether patients want this information, whether it facilitates their decision-making for surgery, and how it is best communicated to them. Disclosure of personal performance rates during informed consent has the potential benefits of enhancing patient autonomy, improving patient decision-making, and improving quality of care. The major risks of disclosure include inaccurate and misleading performance rates, avoidance of high-risk cases, unjust damage to surgeon's reputations, and jeopardized patient trust. Conclusion: At this time, we think that, for most conditions, surgical procedures, and outcomes, the accuracy of surgeon- and patient-specific performance rates is illusory, obviating the ethical obligation to communicate them as part of the informed consent process. Nonetheless, the surgical profession has the duty to develop information systems that allow for performance to be evaluated to a high degree of accuracy. In the meantime, patients should be informed of the quantity of

  12. Individual Performance: From Common Source Bias to Institutionalized Assessment

    DEFF Research Database (Denmark)

    Andersen, Lotte Bøgh; Heinesen, Eskil; Pedersen, Lene Holm

    2016-01-01

    theory and the sociology of professions. Empirically, we ask whether different measures of individual performance produce different results. The investigated performance measures vary with regard to risk of common data source bias, standardization of assessment criteria, and external verification...... dimension for the same teachers: the teachers' self-reported contributions to students' academic skills, the students' marks for the year's work given by the teacher, marks in oral exams with one external examiner and the teacher, and marks in written exams with at least one external examiner....... The associations are systematically stronger when the performance measure comes from the same data source as the explanatory variables, but when separate data sources are used and the measurement scale is institutionalized, the level of external verification does not matter much. Based on institutional theory...

  13. The Power of Individual-level Drivers of Inventive Performance

    DEFF Research Database (Denmark)

    Zwick, Thomas; Frosch, Katharina; Hoisl, Karin

    2017-01-01

    (KSAO) model. We link survey information spanning the inventors’ entire careers and psychometric test evidence with patent history data for more than 1000 inventors. We also control for variables that have traditionally been used in studies of inventive performance including inventor age, applicant type......, technology, patent, and time information. We show that educational level, skills acquired during the career, personality traits, career motivation, cognitive ability, and cognitive problem-solving style are significantly related to inventive performance....

  14. Improved Mental Acuity Forecasting with an Individualized Quantitative Sleep Model

    Directory of Open Access Journals (Sweden)

    Brent D. Winslow

    2017-04-01

    Full Text Available Sleep impairment significantly alters human brain structure and cognitive function, but available evidence suggests that adults in developed nations are sleeping less. A growing body of research has sought to use sleep to forecast cognitive performance by modeling the relationship between the two, but has generally focused on vigilance rather than other cognitive constructs affected by sleep, such as reaction time, executive function, and working memory. Previous modeling efforts have also utilized subjective, self-reported sleep durations and were restricted to laboratory environments. In the current effort, we addressed these limitations by employing wearable systems and mobile applications to gather objective sleep information, assess multi-construct cognitive performance, and model/predict changes to mental acuity. Thirty participants were recruited for participation in the study, which lasted 1 week. Using the Fitbit Charge HR and a mobile version of the automated neuropsychological assessment metric called CogGauge, we gathered a series of features and utilized the unified model of performance to predict mental acuity based on sleep records. Our results suggest that individuals poorly rate their sleep duration, supporting the need for objective sleep metrics to model circadian changes to mental acuity. Participant compliance in using the wearable throughout the week and responding to the CogGauge assessments was 80%. Specific biases were identified in temporal metrics across mobile devices and operating systems and were excluded from the mental acuity metric development. Individualized prediction of mental acuity consistently outperformed group modeling. This effort indicates the feasibility of creating an individualized, mobile assessment and prediction of mental acuity, compatible with the majority of current mobile devices.

  15. Predictive performance models and multiple task performance

    Science.gov (United States)

    Wickens, Christopher D.; Larish, Inge; Contorer, Aaron

    1989-01-01

    Five models that predict how performance of multiple tasks will interact in complex task scenarios are discussed. The models are shown in terms of the assumptions they make about human operator divided attention. The different assumptions about attention are then empirically validated in a multitask helicopter flight simulation. It is concluded from this simulation that the most important assumption relates to the coding of demand level of different component tasks.

  16. Cross-cultural adaptation of the Individual Work Performance Questionnaire.

    Science.gov (United States)

    Koopmans, Linda; Bernaards, Claire M; Hildebrandt, Vincent H; Lerner, Debra; de Vet, Henrica C W; van der Beek, Allard J

    2015-01-01

    The Individual Work Performance Questionnaire (IWPQ), measuring task performance, contextual performance, and counterproductive work behavior, was developed in The Netherlands. To cross-culturally adapt the IWPQ from the Dutch to the American-English language, and assess the questionnaire's internal consistency and content validity in the American-English context. A five stage translation and adaptation process was used: forward translation, synthesis, back-translation, expert committee review, and pilot-testing. During the pilot-testing, cognitive interviews with 40 American workers were performed, to examine the comprehensibility, applicability, and completeness of the American-English IWPQ. Questionnaire instructions were slightly modified to aid interpretation in the American-English language. Inconsistencies with verb tense were identified, and it was decided to consistently use simple past tense. The wording of five items was modified to better suit the American-English language. In general, participants were positive on the comprehensibility, applicability and completeness of the questionnaire during the pilot-testing phase. Furthermore, the study showed positive results concerning the internal consistency (Cronbach's alphas for the scales between 0.79-0.89) and content validity of the American-English IWPQ. The results indicate that the cross-cultural adaptation of the American-English IWPQ was successful and that the measurement properties of the translated version are promising.

  17. Factors Influencing Individual Performance In An Indonesian Government Office

    Directory of Open Access Journals (Sweden)

    Azizatul Munawaroh

    2013-11-01

    Full Text Available 1024x768 Reformation in Indonesian government offices leads to many substantial changes, and demands improved job performances while arguably loading employees with more work. This research aims to understand factors that potentially influence job performance in Indonesian government offices that carries on such reformation. Using adapted scales from previous studies, this research investigates the role of workload, responsibility for others (level of responsibility to care for other people and need for achievement on employee’s performance.  A survey to all full-time workers in an Indonesian government office is conducted. Contrary to expectation, workload does not influence employee’s performance. Instead, regression analysis demonstrates that, employee’s need for achievement and responsibility for others are significant factors affecting individual performance. These results are important because they highlight the significance of need for achievement for the success of reformation in this office, and by extension for reformation in Indonesia. The results are also interesting because this is the first study that points out to the role of responsibility for others in influencing individual performance in Indonesia which is characterized by collectivistic culture. This paper discusses the contributions of these results for theory and practice.   Keywords: Indonesian public, need for achievement, responsibility for others, workload. Normal 0 false false false IN X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso

  18. INDIVIDUAL-BASED MODELS: POWERFUL OR POWER STRUGGLE?

    Science.gov (United States)

    Willem, L; Stijven, S; Hens, N; Vladislavleva, E; Broeckhove, J; Beutels, P

    2015-01-01

    Individual-based models (IBMs) offer endless possibilities to explore various research questions but come with high model complexity and computational burden. Large-scale IBMs have become feasible but the novel hardware architectures require adapted software. The increased model complexity also requires systematic exploration to gain thorough system understanding. We elaborate on the development of IBMs for vaccine-preventable infectious diseases and model exploration with active learning. Investment in IBM simulator code can lead to significant runtime reductions. We found large performance differences due to data locality. Sorting the population once, reduced simulation time by a factor two. Storing person attributes separately instead of using person objects also seemed more efficient. Next, we improved model performance up to 70% by structuring potential contacts based on health status before processing disease transmission. The active learning approach we present is based on iterative surrogate modelling and model-guided experimentation. Symbolic regression is used for nonlinear response surface modelling with automatic feature selection. We illustrate our approach using an IBM for influenza vaccination. After optimizing the parameter spade, we observed an inverse relationship between vaccination coverage and the clinical attack rate reinforced by herd immunity. These insights can be used to focus and optimise research activities, and to reduce both dimensionality and decision uncertainty.

  19. Behavior model for performance assessment

    International Nuclear Information System (INIS)

    Brown-VanHoozer, S. A.

    1999-01-01

    Every individual channels information differently based on their preference of the sensory modality or representational system (visual auditory or kinesthetic) we tend to favor most (our primary representational system (PRS)). Therefore, some of us access and store our information primarily visually first, some auditorily, and others kinesthetically (through feel and touch); which in turn establishes our information processing patterns and strategies and external to internal (and subsequently vice versa) experiential language representation. Because of the different ways we channel our information, each of us will respond differently to a task--the way we gather and process the external information (input), our response time (process), and the outcome (behavior). Traditional human models of decision making and response time focus on perception, cognitive and motor systems stimulated and influenced by the three sensory modalities, visual, auditory and kinesthetic. For us, these are the building blocks to knowing how someone is thinking. Being aware of what is taking place and how to ask questions is essential in assessing performance toward reducing human errors. Existing models give predications based on time values or response times for a particular event, and may be summed and averaged for a generalization of behavior(s). However, by our not establishing a basic understanding of the foundation of how the behavior was predicated through a decision making strategy process, predicative models are overall inefficient in their analysis of the means by which behavior was generated. What is seen is the end result

  20. Behavior model for performance assessment.

    Energy Technology Data Exchange (ETDEWEB)

    Borwn-VanHoozer, S. A.

    1999-07-23

    Every individual channels information differently based on their preference of the sensory modality or representational system (visual auditory or kinesthetic) we tend to favor most (our primary representational system (PRS)). Therefore, some of us access and store our information primarily visually first, some auditorily, and others kinesthetically (through feel and touch); which in turn establishes our information processing patterns and strategies and external to internal (and subsequently vice versa) experiential language representation. Because of the different ways we channel our information, each of us will respond differently to a task--the way we gather and process the external information (input), our response time (process), and the outcome (behavior). Traditional human models of decision making and response time focus on perception, cognitive and motor systems stimulated and influenced by the three sensory modalities, visual, auditory and kinesthetic. For us, these are the building blocks to knowing how someone is thinking. Being aware of what is taking place and how to ask questions is essential in assessing performance toward reducing human errors. Existing models give predications based on time values or response times for a particular event, and may be summed and averaged for a generalization of behavior(s). However, by our not establishing a basic understanding of the foundation of how the behavior was predicated through a decision making strategy process, predicative models are overall inefficient in their analysis of the means by which behavior was generated. What is seen is the end result.

  1. Individual Subjective Initiative Merge Model Based on Cellular Automaton

    Directory of Open Access Journals (Sweden)

    Yin-Jie Xu

    2013-01-01

    Full Text Available The merge control models proposed for work zones are classified into two types (Hard Control Merge (HCM model and Soft Control Merge (SCM model according to their own control intensity and are compared with a new model, called Individual Subjective Initiative Merge (ISIM model, which is based on the linear lane-changing probability strategy in the merging area. The attention of this paper is paid to the positive impact of the individual subjective initiative for the whole traffic system. Three models (ISIM, HCM, and SCM are established and compared with each other by two order parameters, that is, system output and average vehicle travel time. Finally, numerical results show that both ISIM and SCM perform better than HCM. Compared with SCM, the output of ISIM is 20 vehicles per hour higher under the symmetric input condition and is more stable under the asymmetric input condition. Meanwhile, the average travel time of ISIM is 2000 time steps less under the oversaturated input condition.

  2. Model and Analysis of Individual Rehearsals

    DEFF Research Database (Denmark)

    Jensen, Kristoffer; Frimodt-Møller, Søren

    2013-01-01

    to the score and the instrument, respectively, when applicable. Via these observations, hypotheses are formed and discussed regarding the development of a musician’s Long Term Memory (LTM) in relation to the score, as well as how much s/he is able to store in Short Term Memory (STM) while playing....... of this attention over time, and discusses how this attention is dependent on the musician’s ability to memorize. A selection of musicians (playing guitar, bass clarinet, or violin) was made to individually rehearse short pieces (by Beethoven and Bach) up to and exceeding 20 times. The musicians were instructed...

  3. Effects of compression and individual variability on face recognition performance

    Science.gov (United States)

    McGarry, Delia P.; Arndt, Craig M.; McCabe, Steven A.; D'Amato, Donald P.

    2004-08-01

    The Enhanced Border Security and Visa Entry Reform Act of 2002 requires that the Visa Waiver Program be available only to countries that have a program to issue to their nationals machine-readable passports incorporating biometric identifiers complying with applicable standards established by the International Civil Aviation Organization (ICAO). In June 2002, the New Technologies Working Group of ICAO unanimously endorsed the use of face recognition (FR) as the globally interoperable biometric for machine-assisted identity confirmation with machine-readable travel documents (MRTDs), although Member States may elect to use fingerprint and/or iris recognition as additional biometric technologies. The means and formats are still being developed through which biometric information might be stored in the constrained space of integrated circuit chips embedded within travel documents. Such information will be stored in an open, yet unalterable and very compact format, probably as digitally signed and efficiently compressed images. The objective of this research is to characterize the many factors that affect FR system performance with respect to the legislated mandates concerning FR. A photograph acquisition environment and a commercial face recognition system have been installed at Mitretek, and over 1,400 images have been collected of volunteers. The image database and FR system are being used to analyze the effects of lossy image compression, individual differences, such as eyeglasses and facial hair, and the acquisition environment on FR system performance. Images are compressed by varying ratios using JPEG2000 to determine the trade-off points between recognition accuracy and compression ratio. The various acquisition factors that contribute to differences in FR system performance among individuals are also being measured. The results of this study will be used to refine and test efficient face image interchange standards that ensure highly accurate recognition, both

  4. Principles of Sonar Performance Modeling

    NARCIS (Netherlands)

    Ainslie, M.A.

    2010-01-01

    Sonar performance modelling (SPM) is concerned with the prediction of quantitative measures of sonar performance, such as probability of detection. It is a multidisciplinary subject, requiring knowledge and expertise in the disparate fields of underwater acoustics, acoustical oceanography, sonar

  5. Estimation of Nonlinear Dynamic Panel Data Models with Individual Effects

    Directory of Open Access Journals (Sweden)

    Yi Hu

    2014-01-01

    Full Text Available This paper suggests a generalized method of moments (GMM based estimation for dynamic panel data models with individual specific fixed effects and threshold effects simultaneously. We extend Hansen’s (Hansen, 1999 original setup to models including endogenous regressors, specifically, lagged dependent variables. To address the problem of endogeneity of these nonlinear dynamic panel data models, we prove that the orthogonality conditions proposed by Arellano and Bond (1991 are valid. The threshold and slope parameters are estimated by GMM, and asymptotic distribution of the slope parameters is derived. Finite sample performance of the estimation is investigated through Monte Carlo simulations. It shows that the threshold and slope parameter can be estimated accurately and also the finite sample distribution of slope parameters is well approximated by the asymptotic distribution.

  6. Identification of the Predictive Power of Five Factor Personality Traits for Individual Instrument Performance Anxiety

    Science.gov (United States)

    Özdemir, Gökhan; Dalkiran, Esra

    2017-01-01

    This study, with the aim of identifying the predictive power of the five-factor personality traits of music teacher candidates on individual instrument performance anxiety, was designed according to the relational screening model. The study population was students attending the Music Education branch of Fine Arts Education Departments in…

  7. Cognitive performance modeling based on general systems performance theory.

    Science.gov (United States)

    Kondraske, George V

    2010-01-01

    General Systems Performance Theory (GSPT) was initially motivated by problems associated with quantifying different aspects of human performance. It has proved to be invaluable for measurement development and understanding quantitative relationships between human subsystem capacities and performance in complex tasks. It is now desired to bring focus to the application of GSPT to modeling of cognitive system performance. Previous studies involving two complex tasks (i.e., driving and performing laparoscopic surgery) and incorporating measures that are clearly related to cognitive performance (information processing speed and short-term memory capacity) were revisited. A GSPT-derived method of task analysis and performance prediction termed Nonlinear Causal Resource Analysis (NCRA) was employed to determine the demand on basic cognitive performance resources required to support different levels of complex task performance. This approach is presented as a means to determine a cognitive workload profile and the subsequent computation of a single number measure of cognitive workload (CW). Computation of CW may be a viable alternative to measuring it. Various possible "more basic" performance resources that contribute to cognitive system performance are discussed. It is concluded from this preliminary exploration that a GSPT-based approach can contribute to defining cognitive performance models that are useful for both individual subjects and specific groups (e.g., military pilots).

  8. Mental Models, Magical Thinking, And Individual Differences

    Directory of Open Access Journals (Sweden)

    Phil Turner

    2009-01-01

    Full Text Available Broadly, there are two mutually exclusive accounts of how people (non-specialist users reason about and conceptualize interactive technology. The first is based on classical cognitive psychology and is characterized by the term mental model. The second, drawing on concepts from social cognition, observes that people often anthropomorphize technology. We argue that people are able to exhibit both of these quite different styles of cognition, which Baron-Cohen has described as systemizing and empathizing. The former is associated with the drive to analyze, explore, and construct a system, whereas the latter is the ability to spontaneously tune into another’s thoughts and feelings. The propensity to systemize might give rise to a mental model, while the empathizing tendency might tend to anthropomorphize technology. We present an empirical study that lends support for the above position.

  9. Characterising performance of environmental models

    NARCIS (Netherlands)

    Bennett, N.D.; Croke, B.F.W.; Guariso, G.; Guillaume, J.H.A.; Hamilton, S.H.; Jakeman, A.J.; Marsili-Libelli, S.; Newham, L.T.H.; Norton, J.; Perrin, C.; Pierce, S.; Robson, B.; Seppelt, R.; Voinov, A.; Fath, B.D.; Andreassian, V.

    2013-01-01

    In order to use environmental models effectively for management and decision-making, it is vital to establish an appropriate level of confidence in their performance. This paper reviews techniques available across various fields for characterising the performance of environmental models with focus

  10. INDIVIDUAL DIFFERENCES IN WORKING MEMORY PERFORMANCE: «OVERLOAD» EFFECT

    Directory of Open Access Journals (Sweden)

    Yuri G. Pavlov

    2015-01-01

    Full Text Available The aim of this research is to study the relationship betweenfrontal midline theta rhythm changes and individual differences in working memory performance.Methods. The methods involve behavioural testing on the basis of the program for a presentation of stimulus and registration of answers «PsyTask»; method of EEG (electroencephalography; a technique of measurement of efficiency of working memory; the comparative analysis. Software packages EEGLab for Matlab and Fieldtrip are applied while data processing.Results. After the behavioral test all subjects were separated into 2 groups according to their performance: with «highly productive» and «low productive» memory. Specially prepared author’s complete set of the tasks which complexity varied from average to ultrahigh level was offered to participants of experiment –students and employees of the Ural Federal University and Ural Legal Institute of the Ministry of Internal Affairs. Working memory tasks included sets of verbal stimuli for memorizing in strict order without any mental manipulation and sets of similar stimuli for memorizing in alphabetical order (with manipulations. Measured characteristics of theta-rhythm of EEG during information deduction in memory were compared of two groups’ representatives. The obtained data has shown rather uniform and similar dynamics of decrease in quantity of right answers in process of increasing tasks’ complexity. However, changes of a thetarhythm in different groups had sharply expressed distinctions. «Highly productive» examinees have systematic expansion of a theta-rhythm in the central assignments with stabilisation on the most difficult tasks; «low productive» – while tasks performance of average complexity, a sharp falling of theta-rhythm activity is observed after achievement of its maximum activation.Scientific novelty. The working memory «overload» effect and its EEG correlates are demonstrated on a big sample of

  11. Modeling individual animal histories with multistate capture–recapture models

    Science.gov (United States)

    Lebreton, Jean-Dominique; Nichols, James D.; Barker, Richard J.; Pradel, Roger; Spendelow, Jeffrey A.

    2009-01-01

    Many fields of science begin with a phase of exploration and description, followed by investigations of the processes that account for observed patterns. The science of ecology is no exception, and recent decades have seen a focus on understanding key processes underlying the dynamics of ecological systems. In population ecology, emphasis has shifted from the state variable of population size to the demographic processes responsible for changes in this state variable: birth, death, immigration, and emigration. In evolutionary ecology, some of these same demographic processes, rates of birth and death, are also the determinants of fitness. In animal population ecology, the estimation of state variables and their associated vital rates is especially problematic because of the difficulties in sampling such populations and detecting individual animals. Indeed, early capture–recapture models were developed for the purpose of estimating population size, given the reality that all animals are not caught or detected at any sampling occasion. More recently, capture–recapture models for open populations were developed to draw inferences about survival in the face of these same sampling problems. The focus of this paper is on multi‐state mark–recapture models (MSMR), which first appeared in the 1970s but have undergone substantial development in the last 15 years. These models were developed to deal explicitly with biological variation, in that animals in different “states” (classes defined by location, physiology, behavior, reproductive status, etc.) may have different probabilities of survival and detection. Animal transitions between states are also stochastic and themselves of interest. These general models have proven to be extremely useful and provide a way of thinking about a remarkably wide range of important ecological processes. These methods are now at a stage of refinement and sophistication where they can readily be used by biologists to tackle a wide

  12. Multiprocessor performance modeling with ADAS

    Science.gov (United States)

    Hayes, Paul J.; Andrews, Asa M.

    1989-01-01

    A graph managing strategy referred to as the Algorithm to Architecture Mapping Model (ATAMM) appears useful for the time-optimized execution of application algorithm graphs in embedded multiprocessors and for the performance prediction of graph designs. This paper reports the modeling of ATAMM in the Architecture Design and Assessment System (ADAS) to make an independent verification of ATAMM's performance prediction capability and to provide a user framework for the evaluation of arbitrary algorithm graphs. Following an overview of ATAMM and its major functional rules are descriptions of the ADAS model of ATAMM, methods to enter an arbitrary graph into the model, and techniques to analyze the simulation results. The performance of a 7-node graph example is evaluated using the ADAS model and verifies the ATAMM concept by substantiating previously published performance results.

  13. The Impact on Individualizing Student Models on Necessary Practice Opportunities

    Science.gov (United States)

    Lee, Jung In; Brunskill, Emma

    2012-01-01

    When modeling student learning, tutors that use the Knowledge Tracing framework often assume that all students have the same set of model parameters. We find that when fitting parameters to individual students, there is significant variation among the individual's parameters. We examine if this variation is important in terms of instructional…

  14. Individual-based modeling of ecological and evolutionary processes

    NARCIS (Netherlands)

    DeAngelis, D.L.; Mooij, W.M.

    2005-01-01

    Individual-based models (IBMs) allow the explicit inclusion of individual variation in greater detail than do classical differential and difference equation models. Inclusion of such variation is important for continued progress in ecological and evolutionary theory. We provide a conceptual basis

  15. Comparison of Individualized Covert Modeling, Self-Control Desensitization, and Study Skills Training for Alleviation of Test Anxiety.

    Science.gov (United States)

    Harris, Gina; Johhson, Suzanne Bennett

    1980-01-01

    Individualized covert modeling and self-control desensitization substantially reduced self-reported test anxiety. However, the individualized covert modeling group was the only treatment group that showed significant improvement in academic performance. (Author)

  16. CITTP: Computerized Individual Trainer for Team Performance, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — CITTP provides an intelligent tutor system (ITS) framework for individuals to rehearsing their team tasks using computer based high-fidelity simulations. CITTP is...

  17. Feasibility of Using Individual Differences in Emotionality as Predictors of Job Performance

    National Research Council Canada - National Science Library

    Arvey, Richard

    1998-01-01

    .... Third, the authors develop a model of how individual differences in emotional expression, combined with organizational, occupational and job demands, influence the way individuals react to triggering...

  18. Performance of different radiotherapy workload models

    International Nuclear Information System (INIS)

    Barbera, Lisa; Jackson, Lynda D.; Schulze, Karleen; Groome, Patti A.; Foroudi, Farshad; Delaney, Geoff P.; Mackillop, William J.

    2003-01-01

    Purpose: The purpose of this study was to evaluate the performance of different radiotherapy workload models using a prospectively collected dataset of patient and treatment information from a single center. Methods and Materials: Information about all individual radiotherapy treatments was collected for 2 weeks from the three linear accelerators (linacs) in our department. This information included diagnosis code, treatment site, treatment unit, treatment time, fields per fraction, technique, beam type, blocks, wedges, junctions, port films, and Eastern Cooperative Oncology Group (ECOG) performance status. We evaluated the accuracy and precision of the original and revised basic treatment equivalent (BTE) model, the simple and complex Addenbrooke models, the equivalent simple treatment visit (ESTV) model, fields per hour, and two local standards of workload measurement. Results: Data were collected for 2 weeks in June 2001. During this time, 151 patients were treated with 857 fractions. The revised BTE model performed better than the other models with a mean vertical bar observed - predicted vertical bar of 2.62 (2.44-2.80). It estimated 88.0% of treatment times within 5 min, which is similar to the previously reported accuracy of the model. Conclusion: The revised BTE model had similar accuracy and precision for data collected in our center as it did for the original dataset and performed the best of the models assessed. This model would have uses for patient scheduling, and describing workloads and case complexity

  19. Performance Feedback: Individual Based Reflections and the Effect on Motivation

    OpenAIRE

    Kaymaz, Kurtulus

    2011-01-01

    There is also enough scientific research proved the positive effect of performance on motivation. The common idea is that the performance feedback improve the technical and behavioral effectiveness of employees which then reflect on the job motivation. Around this idea, performance feedback effect motivation via reducing the performance ambiguity, improving the manager-subordinate relationships, making more easy to achieve goals, supporting the personal development and adapting to change. In ...

  20. Individualism in plant populations: using stochastic differential equations to model individual neighbourhood-dependent plant growth.

    Science.gov (United States)

    Lv, Qiming; Schneider, Manuel K; Pitchford, Jonathan W

    2008-08-01

    We study individual plant growth and size hierarchy formation in an experimental population of Arabidopsis thaliana, within an integrated analysis that explicitly accounts for size-dependent growth, size- and space-dependent competition, and environmental stochasticity. It is shown that a Gompertz-type stochastic differential equation (SDE) model, involving asymmetric competition kernels and a stochastic term which decreases with the logarithm of plant weight, efficiently describes individual plant growth, competition, and variability in the studied population. The model is evaluated within a Bayesian framework and compared to its deterministic counterpart, and to several simplified stochastic models, using distributional validation. We show that stochasticity is an important determinant of size hierarchy and that SDE models outperform the deterministic model if and only if structural components of competition (asymmetry; size- and space-dependence) are accounted for. Implications of these results are discussed in the context of plant ecology and in more general modelling situations.

  1. Case management: a randomized controlled study comparing a neighborhood team and a centralized individual model.

    OpenAIRE

    Eggert, G M; Zimmer, J G; Hall, W J; Friedman, B

    1991-01-01

    This randomized controlled study compared two types of case management for skilled nursing level patients living at home: the centralized individual model and the neighborhood team model. The team model differed from the individual model in that team case managers performed client assessments, care planning, some direct services, and reassessments; they also had much smaller caseloads and were assigned a specific catchment area. While patients in both groups incurred very high estimated healt...

  2. Evaluation of performance of electronic dosimeters for individual monitoring: tests in laboratory

    International Nuclear Information System (INIS)

    Garzon, W.J.; Khoury, H.J.; Barros, V.S.M. de; Medeiros, R.B.

    2015-01-01

    Electronic dosimeters based on direct ion storage technology are being widely used in many countries for individual monitoring in many applications of ionizing radiation. However, their use as routine dosimeter has been established in a few countries due to lack of accreditation or intercomparison programs. The objective of this study is to evaluate the performance of two direct íon storage dosimeters model available in the international market: the Miriom-Instadose-1 and RADOS DIS-1 to be eventually accepted for individual monitoring in Brazil. (author)

  3. How is individualization in constraint-induced movement therapy performed?

    DEFF Research Database (Denmark)

    Hansen, Gunhild Mo; Pallesen, Hanne; Normann, Britt

    2016-01-01

    compensatory strategies in the more affected upper limb. Non-participatory observations of four individuals undergoing CIMT group training with a physiotherapist were conducted, followed by theme-based content analysis using concepts from practice knowledge and movement analysis as analytical tools...

  4. Individual differences in infant fearfulness and cognitive performance: a testing, performance, or competence effect?

    Science.gov (United States)

    Rieser-Danner, Loretta A

    2003-02-01

    The author conducted 2 studies to examine the relations between infant fear and cognitive testing performance in 12-month-old infants. In Study 1, fear was assessed by using 2 standard temperament questionnaires and a laboratory-based, standardized stranger approach. Individual differences in cognitive development were assessed using the Object Permanence Scale of the Infant Psychological Development Scales (I. C. Uzgiris & J. M. Hunt, 1975). All 3 assessments of fear significantly predicted object permanence performance, with correlations ranging from -.32 to -.35. In Study 2, fear was assessed via a maternal report questionnaire, and habituation performance was assessed via a basic-level categorization task. Familiarity with the examiner and with the testing environment was manipulated to test for a familiarity influence on performance. Testing revealed individual differences in both fear and habituation. Results suggest that highly fearful infants required more trials to habituate and were less likely to meet the habituation criterion than infants who were less fearful. Methodological and conceptual implications of these results are discussed.

  5. A model of individual differences in learning air traffic control

    NARCIS (Netherlands)

    Taatgen, NA; Altmann, EM; Cleeremans, A; Schunn, CD; Gray, WD

    2001-01-01

    Individual differences in skill acquisition are influenced by several architectural factors. According to Ackerman's theory, general intelligence, speed of proceduralization and psychomotor speed influence different stages of skill acquisition. Ackerman tested this theory by correlating performance

  6. Creativity in online gaming: Individual and dyadic performance in Minecraft

    Directory of Open Access Journals (Sweden)

    Voiskounsky A.E.

    2017-12-01

    Full Text Available Objective: This study was designed to examine possible new aspects of creative activity related to virtual environments. Design: The online gaming interface Minecraft was used to construct (on computer screens complex structures such as buildings from ready-made blocks. Two modes were used: individual and dyadic. Participants (N=49, 29 males and 20 females, 18 to 29 years old, recruited on a snow-ball basis were required to build staying at a distance two complex structures — a ship and a house; each structure was required to be highly creative, i.e. unusual and never seen before. Creativity was evaluated not by the final structure but by the number of ideas generated by the participants and produced either in practice or verbally. Each participant participated once in an individual and once in a dyadic session; the partners were selected randomly. The participants’ verbal activity and digital operations with the Minecraft interface were recorded using the FastStone Capture software package. All the ideas produced by participants were classified in accordance with the following criteria: type (conceptual, functional, selective, corrective, and intentional; level of the structure which the ideas referred to (the whole structure, a particular component of the structure, or an element of the structure; and the status of the verbalized ideas (implemented or unimplemented. Results and Conclusion: The results show that participants produced significantly more ideas and took significantly less time to build the prescribed structure (a house or a ship within the individual session compared to the dyadic session. The originality of their ideas was measured by two psychologists independently: the two measures turned out to be close (r=0.876; the number of original ideas produced during individual and dyadic sessions do not differ significantly. Analysis of the implementation of the ideas showed that, within the dyadic sessions, participants produced

  7. A model for individual egg production in chickens

    NARCIS (Netherlands)

    Grossman, M.; Koops, W.J.

    2001-01-01

    Our primary objective was to improve on an existing model for the individual weekly egg production curve by modeling the curve as a sum of logistic functions: one for the increasing phase of production and a sum for the decreasing phases. To illustrate the model, we used four data sets from two

  8. N-Back auditory test performance in normal individuals

    Directory of Open Access Journals (Sweden)

    Vanessa Tomé Gonçalves

    Full Text Available Abstract The working memory construct refers to the capacity to maintain information for a limited time. Objectives: To devise stimuli and adapt the 5-back test and to verify the effect of age in normal Brazilian individuals. Methods: 31 healthy adults (15 young adults and 16 older adults were evaluated by batteries of auditory stimuli to verify the inter-group differences (age effect in working memory span, total correct answers and intrusions, and the intra-group effect of type of stimulus. Results: There was no intra-group stimulus effect. Individuals from both groups processed di and tri-syllables similarly. No difference between groups (no age effect was observed for any N-Back parameters: total score, span, number of intrusions, in either di or tri-syllable presentation. Conclusion: the processing capacity of 5 elements in phonological working memory was not affected by age.

  9. Modeling structural, dyadic, and individual factors: the inclusion and exclusion model of HIV related behavior.

    Science.gov (United States)

    Albarracin, Dolores; Tannenbaum, Melanie B; Glasman, Laura R; Rothman, Alexander J

    2010-12-01

    Changing HIV-related behaviors requires addressing the individual, dyadic, and structural influences that shape them. This supplement of AIDS & Behavior presents frameworks that integrate these three influences on behavior. Concepts from these frameworks were selected to model the processes by which structural factors affect individual HIV-related behavior. In the Inclusion/Exclusion Model, material and symbolic inclusions and exclusions (sharing versus denying resources) regulate individuals' ability and motivation to detect, prevent, and treat HIV. Structural interventions create inclusions that increase one's ability or motivation to perform these behaviors or exclusions that hinder one's ability or motivation to execute counterproductive behaviors. The need to expand research regarding multilevel influences on HIV-related behavior is also discussed, particularly concerning further understanding of sustained behavior change and effective dissemination of evidence-based intervention strategies.

  10. Modelling of individual subject ozone exposure response kinetics.

    Science.gov (United States)

    Schelegle, Edward S; Adams, William C; Walby, William F; Marion, M Susan

    2012-06-01

    A better understanding of individual subject ozone (O(3)) exposure response kinetics will provide insight into how to improve models used in the risk assessment of ambient ozone exposure. To develop a simple two compartment exposure-response model that describes individual subject decrements in forced expiratory volume in one second (FEV(1)) induced by the acute inhalation of O(3) lasting up to 8 h. FEV(1) measurements of 220 subjects who participated in 14 previously completed studies were fit to the model using both particle swarm and nonlinear least squares optimization techniques to identify three subject-specific coefficients producing minimum "global" and local errors, respectively. Observed and predicted decrements in FEV(1) of the 220 subjects were used for validation of the model. Further validation was provided by comparing the observed O(3)-induced FEV(1) decrements in an additional eight studies with predicted values obtained using model coefficients estimated from the 220 subjects used in cross validation. Overall the individual subject measured and modeled FEV(1) decrements were highly correlated (mean R(2) of 0.69 ± 0.24). In addition, it was shown that a matrix of individual subject model coefficients can be used to predict the mean and variance of group decrements in FEV(1). This modeling approach provides insight into individual subject O(3) exposure response kinetics and provides a potential starting point for improving the risk assessment of environmental O(3) exposure.

  11. A Network-Individual-Resource Model for HIV Prevention

    Science.gov (United States)

    Johnson, Blair T.; Redding, Colleen A.; DiClemente, Ralph J.; Mustanski, Brian S.; Dodge, Brian M.; Sheeran, Paschal; Warren, Michelle R.; Zimmerman, Rick S.; Fisher, William A.; Conner, Mark T.; Carey, Michael P.; Fisher, Jeffrey D.; Stall, Ronald D.; Fishbein, Martin

    2014-01-01

    HIV is transmitted through dyadic exchanges of individuals linked in transitory or permanent networks of varying sizes. To optimize prevention efficacy, a complementary theoretical perspective that bridges key individual level elements with important network elements can be a foundation for developing and implementing HIV interventions with outcomes that are more sustainable over time and have greater dissemination potential. Toward that end, we introduce a Network-Individual-Resource (NIR) model for HIV prevention that recognizes how exchanges of resources between individuals and their networks underlies and sustains HIV-risk behaviors. Individual behavior change for HIV prevention, then, may be dependent on increasing the supportiveness of that individual's relevant networks for such change. Among other implications, an NIR model predicts that the success of prevention efforts depends on whether the prevention efforts (1) prompt behavior changes that can be sustained by the resources the individual or their networks possess; (2) meet individual and network needs and are consistent with the individual's current situation/developmental stage; (3) are trusted and valued; and (4) target high HIV-prevalence networks. PMID:20862606

  12. Dosha brain-types: A neural model of individual differences.

    Science.gov (United States)

    Travis, Frederick T; Wallace, Robert Keith

    2015-01-01

    This paper explores brain patterns associated with the three categories of regulatory principles of the body, mind, and behavior in Ayurveda, called Vata, Pitta, and Kapha dosha. A growing body of research has reported patterns of blood chemistry, genetic expression, physiological states, and chronic diseases associated with each dosha type. Since metabolic and growth factors are controlled by the nervous system, each dosha type should be associated with patterns of functioning of six major areas of the nervous system: The prefrontal cortex, the reticular activating system, the autonomic nervous system, the enteric nervous system, the limbic system, and the hypothalamus. For instance, the prefrontal cortex, which includes the anterior cingulate, ventral medial, and the dorsal lateral cortices, would exhibit a high range of functioning in the Vata brain-type leading to the possibility of being easily overstimulated. The Vata brain-type performs activity quickly. Learns quickly and forgets quickly. Their fast mind gives them an edge in creative problem solving. The Pitta brain-type reacts strongly to all challenges leading to purposeful and resolute actions. They never give up and are very dynamic and goal oriented. The Kapha brain-type is slow and steady leading to methodical thinking and action. They prefer routine and needs stimulation to get going. A model of dosha brain-types could provide a physiological foundation to understand individual differences. This model could help individualize treatment modalities to address different mental and physical dysfunctions. It also could explain differences in behavior seen in clinical as well as in normal populations.

  13. Dosha brain-types: A neural model of individual differences

    Directory of Open Access Journals (Sweden)

    Frederick T Travis

    2015-01-01

    Full Text Available This paper explores brain patterns associated with the three categories of regulatory principles of the body, mind, and behavior in Ayurveda, called Vata, Pitta, and Kapha dosha. A growing body of research has reported patterns of blood chemistry, genetic expression, physiological states, and chronic diseases associated with each dosha type. Since metabolic and growth factors are controlled by the nervous system, each dosha type should be associated with patterns of functioning of six major areas of the nervous system: The prefrontal cortex, the reticular activating system, the autonomic nervous system, the enteric nervous system, the limbic system, and the hypothalamus. For instance, the prefrontal cortex, which includes the anterior cingulate, ventral medial, and the dorsal lateral cortices, would exhibit a high range of functioning in the Vata brain-type leading to the possibility of being easily overstimulated. The Vata brain-type performs activity quickly. Learns quickly and forgets quickly. Their fast mind gives them an edge in creative problem solving. The Pitta brain-type reacts strongly to all challenges leading to purposeful and resolute actions. They never give up and are very dynamic and goal oriented. The Kapha brain-type is slow and steady leading to methodical thinking and action. They prefer routine and needs stimulation to get going. A model of dosha brain-types could provide a physiological foundation to understand individual differences. This model could help individualize treatment modalities to address different mental and physical dysfunctions. It also could explain differences in behavior seen in clinical as well as in normal populations.

  14. Predicting Performance Under Acute Stress : The Role of Individual Characteristics

    NARCIS (Netherlands)

    Delahaij, R.; Dam, K. van; Gaillard, A.W.K.; Soeters, J.

    2011-01-01

    This prospective study examined how differences in coping style, coping self-efficacy, and metacognitive awareness influence coping behavior and performance during a realistic acute stressful exercise in 2 military samples (n = 122 and n = 132). Results showed that coping self-efficacy and coping

  15. Individual match approach to Bowling performance measures in ...

    African Journals Online (AJOL)

    Match conditions can play a significant role in player performances in a cricket match. If the pitch is in a good condition, the batsmen can achieve good scores, making it difficult for the bowlers. In the case of an uneven pitch or adverse weather conditions, the bowlers may have the upper hand. In order to measure bowlers' ...

  16. Performability Modelling Tools, Evaluation Techniques and Applications

    NARCIS (Netherlands)

    Haverkort, Boudewijn R.H.M.

    1990-01-01

    This thesis deals with three aspects of quantitative evaluation of fault-tolerant and distributed computer and communication systems: performability evaluation techniques, performability modelling tools, and performability modelling applications. Performability modelling is a relatively new

  17. Hybrid Modelling of Individual Movement and Collective Behaviour

    KAUST Repository

    Franz, Benjamin

    2013-01-01

    Mathematical models of dispersal in biological systems are often written in terms of partial differential equations (PDEs) which describe the time evolution of population-level variables (concentrations, densities). A more detailed modelling approach is given by individual-based (agent-based) models which describe the behaviour of each organism. In recent years, an intermediate modelling methodology - hybrid modelling - has been applied to a number of biological systems. These hybrid models couple an individual-based description of cells/animals with a PDE-model of their environment. In this chapter, we overview hybrid models in the literature with the focus on the mathematical challenges of this modelling approach. The detailed analysis is presented using the example of chemotaxis, where cells move according to extracellular chemicals that can be altered by the cells themselves. In this case, individual-based models of cells are coupled with PDEs for extracellular chemical signals. Travelling waves in these hybrid models are investigated. In particular, we show that in contrary to the PDEs, hybrid chemotaxis models only develop a transient travelling wave. © 2013 Springer-Verlag Berlin Heidelberg.

  18. Individual performance and leader's laterality in interactive contests.

    Science.gov (United States)

    Mukherjee, Satyam

    2017-05-01

    Left-handedness is known to provide an intrinsic and tactical advantage at top level in many sports involving interactive contests. Again, most of the renowned leaders of the world are known to have been left-handed. Leadership plays an important role in politics, sports and mentorship. In this paper we show that Cricket captains who bat left-handed have a strategic advantage over the right-handed captains in One Day International (ODI) and Test matches. The present study involving 46 left-handed captains and 148 right-handed captains in ODI matches, reveal a strong relation between leader's laterality and team member performance, demonstrating the critical importance of left-handedness and successful leadership. The odds for superior batting performance in an ODI match under left-handed captains are 89% higher than the odds under right-handed captains. Our study shows that left-handed captains are more successful in extracting superior performance from the batsmen and bowlers in ODI and Test matches; perhaps indicating left-handed leaders are better motivators as leaders when compared to right-handed captains.

  19. Simulating individual-based models of epidemics in hierarchical networks

    NARCIS (Netherlands)

    Quax, R.; Bader, D.A.; Sloot, P.M.A.

    2009-01-01

    Current mathematical modeling methods for the spreading of infectious diseases are too simplified and do not scale well. We present the Simulator of Epidemic Evolution in Complex Networks (SEECN), an efficient simulator of detailed individual-based models by parameterizing separate dynamics

  20. Individual Learning Accounts and Other Models of Financing Lifelong Learning

    Science.gov (United States)

    Schuetze, Hans G.

    2007-01-01

    To answer the question "Financing what?" this article distinguishes several models of lifelong learning as well as a variety of lifelong learning activities. Several financing methods are briefly reviewed, however the principal focus is on Individual Learning Accounts (ILAs) which were seen by some analysts as a promising model for…

  1. Individual differences in object permanence performance at 8 months: locomotor experience and brain electrical activity.

    Science.gov (United States)

    Bell, M A; Fox, N A

    1997-12-01

    This work was designed to investigate individual differences in hands-and-knees crawling and frontal brain electrical activity with respect to object permanence performance in 76 eight-month-old infants. Four groups of infants (one prelocomotor and 3 with varying lengths of hands-and-knees crawling experience) were tested on an object permanence scale in a research design similar to that used by Kermoian and Campos (1988). In addition, baseline EEG was recorded and used as an indicator of brain development, as in the Bell and Fox (1992) longitudinal study. Individual differences in frontal and occipital EEG power and in locomotor experience were associated with performance on the object permanence task. Infants successful at A-not-B exhibited greater frontal EEG power and greater occipital EEG power than unsuccessful infants. In contrast to Kermoian and Campos (1988), who noted that long-term crawling experience was associated with higher performance on an object permanence scale, infants in this study with any amount of hands and knees crawling experience performed at a higher level on the object permanence scale than prelocomotor infants. There was no interaction among brain electrical activity, locomotor experience, and object permanence performance. These data highlight the value of electrophysiological research and the need for a brain-behavior model of object permanence performance that incorporates both electrophysiological and behavioral factors.

  2. Individual-based modeling of ecological and evolutionary processes

    Science.gov (United States)

    DeAngelis, Donald L.; Mooij, Wolf M.

    2005-01-01

    Individual-based models (IBMs) allow the explicit inclusion of individual variation in greater detail than do classical differential-equation and difference-equation models. Inclusion of such variation is important for continued progress in ecological and evolutionary theory. We provide a conceptual basis for IBMs by describing five major types of individual variation in IBMs: spatial, ontogenetic, phenotypic, cognitive, and genetic. IBMs are now used in almost all subfields of ecology and evolutionary biology. We map those subfields and look more closely at selected key papers on fish recruitment, forest dynamics, sympatric speciation, metapopulation dynamics, maintenance of diversity, and species conservation. Theorists are currently divided on whether IBMs represent only a practical tool for extending classical theory to more complex situations, or whether individual-based theory represents a radically new research program. We feel that the tension between these two poles of thinking can be a source of creativity in ecology and evolutionary theory.

  3. Data management system performance modeling

    Science.gov (United States)

    Kiser, Larry M.

    1993-01-01

    This paper discusses analytical techniques that have been used to gain a better understanding of the Space Station Freedom's (SSF's) Data Management System (DMS). The DMS is a complex, distributed, real-time computer system that has been redesigned numerous times. The implications of these redesigns have not been fully analyzed. This paper discusses the advantages and disadvantages for static analytical techniques such as Rate Monotonic Analysis (RMA) and also provides a rationale for dynamic modeling. Factors such as system architecture, processor utilization, bus architecture, queuing, etc. are well suited for analysis with a dynamic model. The significance of performance measures for a real-time system are discussed.

  4. Individualized Risk Model for Venous Thromboembolism After Total Joint Arthroplasty.

    Science.gov (United States)

    Parvizi, Javad; Huang, Ronald; Rezapoor, Maryam; Bagheri, Behrad; Maltenfort, Mitchell G

    2016-09-01

    Venous thromboembolism (VTE) after total joint arthroplasty (TJA) is a potentially fatal complication. Currently, a standard protocol for postoperative VTE prophylaxis is used that makes little distinction between patients at varying risks of VTE. We sought to develop a simple scoring system identifying patients at higher risk for VTE in whom more potent anticoagulation may need to be administered. Utilizing the National Inpatient Sample data, 1,721,806 patients undergoing TJA were identified, among whom 15,775 (0.9%) developed VTE after index arthroplasty. Among the cohort, all known potential risk factors for VTE were assessed. An initial logistic regression model using potential predictors for VTE was performed. Predictors with little contribution or poor predictive power were pruned from the data, and the model was refit. After pruning of variables that had little to no contribution to VTE risk, using the logistic regression, all independent predictors of VTE after TJA were identified in the data. Relative weights for each factor were determined. Hypercoagulability, metastatic cancer, stroke, sepsis, and chronic obstructive pulmonary disease had some of the highest points. Patients with any of these conditions had risk for postoperative VTE that exceeded the 3% rate. Based on the model, an iOS (iPhone operating system) application was developed (VTEstimator) that could be used to assign patients into low or high risk for VTE after TJA. We believe individualization of VTE prophylaxis after TJA can improve the efficacy of preventing VTE while minimizing untoward risks associated with the administration of anticoagulation. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Individual-based modelling and control of bovine brucellosis

    Science.gov (United States)

    Nepomuceno, Erivelton G.; Barbosa, Alípio M.; Silva, Marcos X.; Perc, Matjaž

    2018-05-01

    We present a theoretical approach to control bovine brucellosis. We have used individual-based modelling, which is a network-type alternative to compartmental models. Our model thus considers heterogeneous populations, and spatial aspects such as migration among herds and control actions described as pulse interventions are also easily implemented. We show that individual-based modelling reproduces the mean field behaviour of an equivalent compartmental model. Details of this process, as well as flowcharts, are provided to facilitate the reproduction of the presented results. We further investigate three numerical examples using real parameters of herds in the São Paulo state of Brazil, in scenarios which explore eradication, continuous and pulsed vaccination and meta-population effects. The obtained results are in good agreement with the expected behaviour of this disease, which ultimately showcases the effectiveness of our theory.

  6. Individual Differences in Cognitive and Noncognitive Abilities and Team Performance in Dynamic Task Environments

    National Research Council Canada - National Science Library

    Doane, Stephanie

    2004-01-01

    The specific goal of this research was to examine the role of individual differences in cognitive and non-cognitive abilities on individual and team performance in a real-time dynamic team-task environment...

  7. A Job Retention Model for Individuals with Mental Retardation

    Science.gov (United States)

    Fornes, Sandra

    2006-01-01

    This structured literature review examines the literature and addresses issues of job retention for adult workers with moderate to mild mental retardation (MR), investigating the relationships between work-related social behaviors, self-determination, person-job congruency of individuals with MR, and their job performance and job satisfaction with…

  8. Individual differences in emotion word processing: A diffusion model analysis.

    Science.gov (United States)

    Mueller, Christina J; Kuchinke, Lars

    2016-06-01

    The exploratory study investigated individual differences in implicit processing of emotional words in a lexical decision task. A processing advantage for positive words was observed, and differences between happy and fear-related words in response times were predicted by individual differences in specific variables of emotion processing: Whereas more pronounced goal-directed behavior was related to a specific slowdown in processing of fear-related words, the rate of spontaneous eye blinks (indexing brain dopamine levels) was associated with a processing advantage of happy words. Estimating diffusion model parameters revealed that the drift rate (rate of information accumulation) captures unique variance of processing differences between happy and fear-related words, with highest drift rates observed for happy words. Overall emotion recognition ability predicted individual differences in drift rates between happy and fear-related words. The findings emphasize that a significant amount of variance in emotion processing is explained by individual differences in behavioral data.

  9. Individual loss reserving with the Multivariate Skew Normal model

    NARCIS (Netherlands)

    Pigeon, M.; Antonio, K.; Denuit, M.

    2011-01-01

    In general insurance, the evaluation of future cash ows and solvency capital has become increasingly important. To assist in this process, the present paper proposes an individual discrete-time loss re- serving model describing the occurrence, the reporting delay, the timeto the first payment, and

  10. Modelling community, family, and individual determinants of childhood dental caries

    NARCIS (Netherlands)

    Duijster, D.; Loveren, C. van; Dusseldorp, E.; Verrips, G.H.W.

    2014-01-01

    This cross-sectional study empirically tested a theoretical model of pathways and inter-relationships among community, family, and individual determinants of childhood dental caries in a sample of 630, 6-year-old children from the Netherlands. Children's decayed, missing, and filled teeth (dmft)

  11. Individual based model of slug population and spatial dynamics

    NARCIS (Netherlands)

    Choi, Y.H.; Bohan, D.A.; Potting, R.P.J.; Semenov, M.A.; Glen, D.M.

    2006-01-01

    The slug, Deroceras reticulatum, is one of the most important pests of agricultural and horticultural crops in UK and Europe. In this paper, a spatially explicit individual based model (IbM) is developed to study the dynamics of a population of D. reticulatum. The IbM establishes a virtual field

  12. Individual Differences in Cognitive and Noncognitive Abilities and Team Performance in Dynamic Task Environments

    National Research Council Canada - National Science Library

    Doane, Stephanie

    2004-01-01

    .... We completed an experiment that required administration of multiple ability tests, developing teams based on ability, and development of computer software to measure individual and team performance...

  13. Off gas condenser performance modelling

    International Nuclear Information System (INIS)

    Cains, P.W.; Hills, K.M.; Waring, S.; Pratchett, A.G.

    1989-12-01

    A suite of three programmes has been developed to model the ruthenium decontamination performance of a vitrification plant off-gas condenser. The stages of the model are: condensation of water vapour, NO x absorption in the condensate, RuO 4 absorption in the condensate. Juxtaposition of these stages gives a package that may be run on an IBM-compatible desktop PC. Experimental work indicates that the criterion [HNO 2 ] > 10 [RuO 4 ] used to determine RuO 4 destruction in solution is probably realistic under condenser conditions. Vapour pressures of RuO 4 over aqueous solutions at 70 o -90 o C are slightly lower than the values given by extrapolating the ln K p vs. T -1 relation derived from lower temperature data. (author)

  14. Data harmonization and model performance

    Science.gov (United States)

    The Joint Committee on Urban Storm Drainage of the International Association for Hydraulic Research (IAHR) and International Association on Water Pollution Research and Control (IAWPRC) was formed in 1982. The current committee members are (no more than two from a country): B. C. Yen, Chairman (USA); P. Harremoes, Vice Chairman (Denmark); R. K. Price, Secretary (UK); P. J. Colyer (UK), M. Desbordes (France), W. C. Huber (USA), K. Krauth (FRG), A. Sjoberg (Sweden), and T. Sueishi (Japan).The IAHR/IAWPRC Joint Committee is forming a Task Group on Data Harmonization and Model Performance. One objective is to promote international urban drainage data harmonization for easy data and information exchange. Another objective is to publicize available models and data internationally. Comments and suggestions concerning the formation and charge of the Task Group are welcome and should be sent to: B. C. Yen, Dept. of Civil Engineering, Univ. of Illinois, 208 N. Romine St., Urbana, IL 61801.

  15. An Individual-based Probabilistic Model for Fish Stock Simulation

    Directory of Open Access Journals (Sweden)

    Federico Buti

    2010-08-01

    Full Text Available We define an individual-based probabilistic model of a sole (Solea solea behaviour. The individual model is given in terms of an Extended Probabilistic Discrete Timed Automaton (EPDTA, a new formalism that is introduced in the paper and that is shown to be interpretable as a Markov decision process. A given EPDTA model can be probabilistically model-checked by giving a suitable translation into syntax accepted by existing model-checkers. In order to simulate the dynamics of a given population of soles in different environmental scenarios, an agent-based simulation environment is defined in which each agent implements the behaviour of the given EPDTA model. By varying the probabilities and the characteristic functions embedded in the EPDTA model it is possible to represent different scenarios and to tune the model itself by comparing the results of the simulations with real data about the sole stock in the North Adriatic sea, available from the recent project SoleMon. The simulator is presented and made available for its adaptation to other species.

  16. Modelling biological invasions: Individual to population scales at interfaces

    KAUST Repository

    Belmonte-Beitia, J.

    2013-10-01

    Extracting the population level behaviour of biological systems from that of the individual is critical in understanding dynamics across multiple scales and thus has been the subject of numerous investigations. Here, the influence of spatial heterogeneity in such contexts is explored for interfaces with a separation of the length scales characterising the individual and the interface, a situation that can arise in applications involving cellular modelling. As an illustrative example, we consider cell movement between white and grey matter in the brain which may be relevant in considering the invasive dynamics of glioma. We show that while one can safely neglect intrinsic noise, at least when considering glioma cell invasion, profound differences in population behaviours emerge in the presence of interfaces with only subtle alterations in the dynamics at the individual level. Transport driven by local cell sensing generates predictions of cell accumulations along interfaces where cell motility changes. This behaviour is not predicted with the commonly used Fickian diffusion transport model, but can be extracted from preliminary observations of specific cell lines in recent, novel, cryo-imaging. Consequently, these findings suggest a need to consider the impact of individual behaviour, spatial heterogeneity and especially interfaces in experimental and modelling frameworks of cellular dynamics, for instance in the characterisation of glioma cell motility. © 2013 Elsevier Ltd.

  17. Modelling biological invasions: Individual to population scales at interfaces

    KAUST Repository

    Belmonte-Beitia, J.; Woolley, T.E.; Scott, J.G.; Maini, P.K.; Gaffney, E.A.

    2013-01-01

    Extracting the population level behaviour of biological systems from that of the individual is critical in understanding dynamics across multiple scales and thus has been the subject of numerous investigations. Here, the influence of spatial heterogeneity in such contexts is explored for interfaces with a separation of the length scales characterising the individual and the interface, a situation that can arise in applications involving cellular modelling. As an illustrative example, we consider cell movement between white and grey matter in the brain which may be relevant in considering the invasive dynamics of glioma. We show that while one can safely neglect intrinsic noise, at least when considering glioma cell invasion, profound differences in population behaviours emerge in the presence of interfaces with only subtle alterations in the dynamics at the individual level. Transport driven by local cell sensing generates predictions of cell accumulations along interfaces where cell motility changes. This behaviour is not predicted with the commonly used Fickian diffusion transport model, but can be extracted from preliminary observations of specific cell lines in recent, novel, cryo-imaging. Consequently, these findings suggest a need to consider the impact of individual behaviour, spatial heterogeneity and especially interfaces in experimental and modelling frameworks of cellular dynamics, for instance in the characterisation of glioma cell motility. © 2013 Elsevier Ltd.

  18. Evaluation of performance of electronic dosimeters for individual monitoring: tests in laboratory; Avaliacao do desempenho de dosimetros eletronicos para monitoracao individual: testes em laboratorio

    Energy Technology Data Exchange (ETDEWEB)

    Garzon, W.J.; Khoury, H.J.; Barros, V.S.M. de, E-mail: wjaramig@gmail.com [Universidade Federal de Pernambuco (UFPE), Recife (Brazil). Departamento de Energia Nuclear. Laboratorio de Metrologia das Radiacoes Ionizantes; Medeiros, R.B. [Universidade Federal de Sao Paulo (EPM/UNIFESP), Sao Paulo, SP (Brazil). Departamento de Diagnostico por Imagem

    2015-07-01

    Electronic dosimeters based on direct ion storage technology are being widely used in many countries for individual monitoring in many applications of ionizing radiation. However, their use as routine dosimeter has been established in a few countries due to lack of accreditation or intercomparison programs. The objective of this study is to evaluate the performance of two direct íon storage dosimeters model available in the international market: the Miriom-Instadose-1 and RADOS DIS-1 to be eventually accepted for individual monitoring in Brazil. (author)

  19. The influence of schooling on working memory performance in elderly individuals without cognitive decline

    Directory of Open Access Journals (Sweden)

    Juliana Nery de Souza-Talarico

    Full Text Available Abstract Over recent decades, research on cognition has been developed rapidly toward better understanding the cognitive changes that usually occur during normal aging. There is evidence that elderly individuals have worse working memory performance than young adults. However, the effect of education on this cognitive function remains unclear. Objectives: To analyze the performance of healthy elderly subjects on working memory tasks and to verify the influence of educational level on this performance. Methods: Forty elderly individuals without cognitive impairment and fully independent, were randomly chosen from a group of subjects participating in cultural activities at the university campus. The Digit Span Forward (DSF test was used to evaluate attention performance. The working memory performance was assessed by the Digit Span Backward (DSB and the difference between DSF and DSB. The data were statistically analyzed using the Spearman's correlation coefficient to verify the correlation between the Digit Span (DS scores and the variables age and schooling, while the Multiple Linear Regression Model was used to verify the effect of these variables on the DS scores. Results: A significant positive correlation (r=0.41, p<0.01 as well as a significant association (b=0.506; p=0.001; CI 95%= 0.064/0.237 were found between years of schooling and DSB scores. It was not observed statistical correlation (r= -0.08, p=0.64 or association (b=0.41; p=0.775; CI 95%= -0.049/0.065 between age and DSB scores. Conclusion: In this study, higher levels of schooling were associated with better working memory performance in cognitively healthy elders.

  20. Individual styles of professional operator's performance for the needs of interplanetary mission.

    Science.gov (United States)

    Boritko, Yaroslav; Gushin, Vadim; Zavalko, Irina; Smoleevskiy, Alexandr; Dudukin, Alexandr

    Maintenance of the cosmonaut’s professional performance reliability is one of the priorities of long-term space flights safety. Cosmonaut’s performance during long-term space flight decreases due to combination of the microgravity effects and inevitable degradation of skills during prolonged breaks in training. Therefore, the objective of the elaboration of countermeasures against skill decrement is very relevant. During the experiment with prolonged isolation "Mars-500" in IMBP two virtual models of professional operator’s activities were used to investigate the influence of extended isolation, monotony and confinement on professional skills degradation. One is well-known “PILOT-1” (docking to the space station), another - "VIRTU" (manned operations of planet exploration). Individual resistance to the artificial sensory conflict was estimated using computerized version of “Mirror koordinograf” with GSR registration. Two different individual performance styles, referring to the different types of response to stress, have been identified. Individual performance style, called "conservative control", manifested in permanent control of parameters, conditions and results of the operator’s activity. Operators with this performance style demonstrate high reliability in performing tasks. The drawback of the style is intensive resource expenditure - both the operator (physiological "cost") and the technical system operated (fuel, time). This style is more efficient while executing tasks that require long work with high reliability required according to a detailed protocol, such as orbital flight. Individual style, called "exploratory ", manifested in the search of new ways of task fulfillment. This style is accompanied by partial, periodic lack of control of the conditions and result of operator’s activity due to flexible approach to the tasks perfect implementation. Operators spent less resource (fuel, time, lower physiological "cost") due to high self

  1. [Individual physical performance capacity with physiological and biochemical indicators of stress].

    Science.gov (United States)

    Bergert, K D; Nestler, K; Böttger, H; Schettler, R

    1989-09-01

    22 health male subjects were exposed by a combination of physical exercises and heat. Strain related physiological and biochemical parameters were measured. Different individual reactions were obtained under controlled conditions. In dependence on the individual performance an increased mobilisation of lactat, free fatty acids and catecholamines were found. The determination of aerob physical performance can be applied for the evaluation of working capacity.

  2. Model Performance Evaluation and Scenario Analysis (MPESA)

    Science.gov (United States)

    Model Performance Evaluation and Scenario Analysis (MPESA) assesses the performance with which models predict time series data. The tool was developed Hydrological Simulation Program-Fortran (HSPF) and the Stormwater Management Model (SWMM)

  3. Illstrative probabilistic biosphere model for Yucca Mountain individual risk calculations

    International Nuclear Information System (INIS)

    Wilems, R.E.

    1994-01-01

    The proposed EPA Standards for the disposal of spent fuel, high-level and transuranic radioactive waste prescribe future biosphere--one in which no sustained human activity occurs inside the controlled zone, yet sustained use of groundwater occurs just outside the controlled zone boundary. Performance assessments have generally assumed a person at this location extracts all his water needs directly from the projected contaminated plume for all of his life. Dose to this maximally-exposed individual is too conservative a measure of performance for a nuclear waste repository and does not reflect the isolation characteristics of a site. A better measure is individual risk in which uncertainties in biosphere characteristics for the longer periods of performance, for a site like Yucca Mountain only those characteristics associated with well water scenarios need be prescribed. Such a prescription of the biosphere is appropriate because the goal of the regulations is to provide indicators of future performance so the regulators can make a responsible decision regarding reasonable assurance of public health and safety

  4. Modeling decisions from experience: How models with a set of parameters for aggregate choices explain individual choices

    Directory of Open Access Journals (Sweden)

    Neha Sharma

    2017-10-01

    Full Text Available One of the paradigms (called “sampling paradigm” in judgment and decision-making involves decision-makers sample information before making a final consequential choice. In the sampling paradigm, certain computational models have been proposed where a set of single or distribution parameters is calibrated to the choice proportions of a group of participants (aggregate and hierarchical models. However, currently little is known on how aggregate and hierarchical models would account for choices made by individual participants in the sampling paradigm. In this paper, we test the ability of aggregate and hierarchical models to explain choices made by individual participants. Several models, Ensemble, Cumulative Prospect Theory (CPT, Best Estimation and Simulation Techniques (BEAST, Natural-Mean Heuristic (NMH, and Instance-Based Learning (IBL, had their parameters calibrated to individual choices in a large dataset involving the sampling paradigm. Later, these models were generalized to two large datasets in the sampling paradigm. Results revealed that the aggregate models (like CPT and IBL accounted for individual choices better than hierarchical models (like Ensemble and BEAST upon generalization to problems that were like those encountered during calibration. Furthermore, the CPT model, which relies on differential valuing of gains and losses, respectively, performed better than other models during calibration and generalization on datasets with similar set of problems. The IBL model, relying on recency and frequency of sampled information, and the NMH model, relying on frequency of sampled information, performed better than other models during generalization to a challenging dataset. Sequential analyses of results from different models showed how these models accounted for transitions from the last sample to final choice in human data. We highlight the implications of using aggregate and hierarchical models in explaining individual choices

  5. Self-employed individuals performing different types of work have different occupational safety and health problems.

    Science.gov (United States)

    Park, Jungsun; Han, Boyoung; Kim, Yangho

    2018-05-22

    We assessed the occupational safety and health (OSH) issues of self-employed individuals in Korea. The working conditions and OSH issues in three groups were analyzed using the Korean Working Conditions Survey of 2014. Among self-employed individuals, "Physical work" was more common among males, whereas "Emotional work" was more common among females. Self-employed individuals performing "Mental work" had more education, higher incomes, and the lowest exposure to physical/chemical and ergonomic hazards in the workplace. In contrast, those performing "Physical work" were older, had less education, lower incomes, greater exposure to physical/chemical and ergonomic hazards in the workplace, and more health problems. Individuals performing "Physical work" were most vulnerable to OSH problems. The self-employed are a heterogeneous group of individuals. We suggest development of specific strategies that focus on workers performing "Physical work" to improve the health and safety of self-employed workers in Korea. © 2018 Wiley Periodicals, Inc.

  6. Early detection of poor adherers to statins: applying individualized surveillance to pay for performance.

    Directory of Open Access Journals (Sweden)

    Andrew J Zimolzak

    Full Text Available Medication nonadherence costs $300 billion annually in the US. Medicare Advantage plans have a financial incentive to increase medication adherence among members because the Centers for Medicare and Medicaid Services (CMS now awards substantive bonus payments to such plans, based in part on population adherence to chronic medications. We sought to build an individualized surveillance model that detects early which beneficiaries will fall below the CMS adherence threshold.This was a retrospective study of over 210,000 beneficiaries initiating statins, in a database of private insurance claims, from 2008-2011. A logistic regression model was constructed to use statin adherence from initiation to day 90 to predict beneficiaries who would not meet the CMS measure of proportion of days covered 0.8 or above, from day 91 to 365. The model controlled for 15 additional characteristics. In a sensitivity analysis, we varied the number of days of adherence data used for prediction.Lower adherence in the first 90 days was the strongest predictor of one-year nonadherence, with an odds ratio of 25.0 (95% confidence interval 23.7-26.5 for poor adherence at one year. The model had an area under the receiver operating characteristic curve of 0.80. Sensitivity analysis revealed that predictions of comparable accuracy could be made only 40 days after statin initiation. When members with 30-day supplies for their first statin fill had predictions made at 40 days, and members with 90-day supplies for their first fill had predictions made at 100 days, poor adherence could be predicted with 86% positive predictive value.To preserve their Medicare Star ratings, plan managers should identify or develop effective programs to improve adherence. An individualized surveillance approach can be used to target members who would most benefit, recognizing the tradeoff between improved model performance over time and the advantage of earlier detection.

  7. Identifying individual changes in performance with composite quality indicators while accounting for regression to the mean.

    Science.gov (United States)

    Gajewski, Byron J; Dunton, Nancy

    2013-04-01

    Almost a decade ago Morton and Torgerson indicated that perceived medical benefits could be due to "regression to the mean." Despite this caution, the regression to the mean "effects on the identification of changes in institutional performance do not seem to have been considered previously in any depth" (Jones and Spiegelhalter). As a response, Jones and Spiegelhalter provide a methodology to adjust for regression to the mean when modeling recent changes in institutional performance for one-variable quality indicators. Therefore, in our view, Jones and Spiegelhalter provide a breakthrough methodology for performance measures. At the same time, in the interests of parsimony, it is useful to aggregate individual quality indicators into a composite score. Our question is, can we develop and demonstrate a methodology that extends the "regression to the mean" literature to allow for composite quality indicators? Using a latent variable modeling approach, we extend the methodology to the composite indicator case. We demonstrate the approach on 4 indicators collected by the National Database of Nursing Quality Indicators. A simulation study further demonstrates its "proof of concept."

  8. Individually adapted imagery improves brain-computer interface performance in end-users with disability.

    Science.gov (United States)

    Scherer, Reinhold; Faller, Josef; Friedrich, Elisabeth V C; Opisso, Eloy; Costa, Ursula; Kübler, Andrea; Müller-Putz, Gernot R

    2015-01-01

    Brain-computer interfaces (BCIs) translate oscillatory electroencephalogram (EEG) patterns into action. Different mental activities modulate spontaneous EEG rhythms in various ways. Non-stationarity and inherent variability of EEG signals, however, make reliable recognition of modulated EEG patterns challenging. Able-bodied individuals who use a BCI for the first time achieve - on average - binary classification performance of about 75%. Performance in users with central nervous system (CNS) tissue damage is typically lower. User training generally enhances reliability of EEG pattern generation and thus also robustness of pattern recognition. In this study, we investigated the impact of mental tasks on binary classification performance in BCI users with central nervous system (CNS) tissue damage such as persons with stroke or spinal cord injury (SCI). Motor imagery (MI), that is the kinesthetic imagination of movement (e.g. squeezing a rubber ball with the right hand), is the "gold standard" and mainly used to modulate EEG patterns. Based on our recent results in able-bodied users, we hypothesized that pair-wise combination of "brain-teaser" (e.g. mental subtraction and mental word association) and "dynamic imagery" (e.g. hand and feet MI) tasks significantly increases classification performance of induced EEG patterns in the selected end-user group. Within-day (How stable is the classification within a day?) and between-day (How well does a model trained on day one perform on unseen data of day two?) analysis of variability of mental task pair classification in nine individuals confirmed the hypothesis. We found that the use of the classical MI task pair hand vs. feed leads to significantly lower classification accuracy - in average up to 15% less - in most users with stroke or SCI. User-specific selection of task pairs was again essential to enhance performance. We expect that the gained evidence will significantly contribute to make imagery-based BCI technology

  9. Individually adapted imagery improves brain-computer interface performance in end-users with disability.

    Directory of Open Access Journals (Sweden)

    Reinhold Scherer

    Full Text Available Brain-computer interfaces (BCIs translate oscillatory electroencephalogram (EEG patterns into action. Different mental activities modulate spontaneous EEG rhythms in various ways. Non-stationarity and inherent variability of EEG signals, however, make reliable recognition of modulated EEG patterns challenging. Able-bodied individuals who use a BCI for the first time achieve - on average - binary classification performance of about 75%. Performance in users with central nervous system (CNS tissue damage is typically lower. User training generally enhances reliability of EEG pattern generation and thus also robustness of pattern recognition. In this study, we investigated the impact of mental tasks on binary classification performance in BCI users with central nervous system (CNS tissue damage such as persons with stroke or spinal cord injury (SCI. Motor imagery (MI, that is the kinesthetic imagination of movement (e.g. squeezing a rubber ball with the right hand, is the "gold standard" and mainly used to modulate EEG patterns. Based on our recent results in able-bodied users, we hypothesized that pair-wise combination of "brain-teaser" (e.g. mental subtraction and mental word association and "dynamic imagery" (e.g. hand and feet MI tasks significantly increases classification performance of induced EEG patterns in the selected end-user group. Within-day (How stable is the classification within a day? and between-day (How well does a model trained on day one perform on unseen data of day two? analysis of variability of mental task pair classification in nine individuals confirmed the hypothesis. We found that the use of the classical MI task pair hand vs. feed leads to significantly lower classification accuracy - in average up to 15% less - in most users with stroke or SCI. User-specific selection of task pairs was again essential to enhance performance. We expect that the gained evidence will significantly contribute to make imagery-based BCI

  10. Design of Individualized Wheelchairs Using AHP and Kano Model

    Directory of Open Access Journals (Sweden)

    Yanli Yuan

    2014-06-01

    Full Text Available To study how to design different grades of individualized wheelchairs according to users' needs, a personalized wheelchair design method based on AHP and Kano model is proposed. The AHP model determines the relative importance of characteristics of customers' demands. The subfunctions of manual wheelchairs and their attributes are given. The weight coefficients are calculated. 20 experts (10 are the members of the research team, 5 are doctors, and 5 are wheelchair designers are involved in the above two parts of the work. Kano model represents the types of user requirements. 30 participants' (wheelchair users needs are divided into 5 categories: M, O, E, I, and R. According to the types of user needs and the weight of each subfunction, three manual wheelchair models are built. Traditional design method usually cannot satisfy the requirements of users and product structure, so this paper makes a contribution to solve this problem. The method can be used to design individualized wheelchairs which may improve the product quality and customers' satisfaction. Meanwhile it also can reduce the design time, thereby reducing the design cost.

  11. A connectionist model of category learning by individuals with high-functioning autism spectrum disorder.

    Science.gov (United States)

    Dovgopoly, Alexander; Mercado, Eduardo

    2013-06-01

    Individuals with autism spectrum disorder (ASD) show atypical patterns of learning and generalization. We explored the possible impacts of autism-related neural abnormalities on perceptual category learning using a neural network model of visual cortical processing. When applied to experiments in which children or adults were trained to classify complex two-dimensional images, the model can account for atypical patterns of perceptual generalization. This is only possible, however, when individual differences in learning are taken into account. In particular, analyses performed with a self-organizing map suggested that individuals with high-functioning ASD show two distinct generalization patterns: one that is comparable to typical patterns, and a second in which there is almost no generalization. The model leads to novel predictions about how individuals will generalize when trained with simplified input sets and can explain why some researchers have failed to detect learning or generalization deficits in prior studies of category learning by individuals with autism. On the basis of these simulations, we propose that deficits in basic neural plasticity mechanisms may be sufficient to account for the atypical patterns of perceptual category learning and generalization associated with autism, but they do not account for why only a subset of individuals with autism would show such deficits. If variations in performance across subgroups reflect heterogeneous neural abnormalities, then future behavioral and neuroimaging studies of individuals with ASD will need to account for such disparities.

  12. DETRA: Model description and evaluation of model performance

    International Nuclear Information System (INIS)

    Suolanen, V.

    1996-01-01

    The computer code DETRA is a generic tool for environmental transfer analyses of radioactive or stable substances. The code has been applied for various purposes, mainly problems related to the biospheric transfer of radionuclides both in safety analyses of disposal of nuclear wastes and in consideration of foodchain exposure pathways in the analyses of off-site consequences of reactor accidents. For each specific application an individually tailored conceptual model can be developed. The biospheric transfer analyses performed by the code are typically carried out for terrestrial, aquatic and food chain applications. 21 refs, 35 figs, 15 tabs

  13. Individual-based model for radiation risk assessment

    Science.gov (United States)

    Smirnova, O.

    A mathematical model is developed which enables one to predict the life span probability for mammals exposed to radiation. It relates statistical biometric functions with statistical and dynamic characteristics of an organism's critical system. To calculate the dynamics of the latter, the respective mathematical model is used too. This approach is applied to describe the effects of low level chronic irradiation on mice when the hematopoietic system (namely, thrombocytopoiesis) is the critical one. For identification of the joint model, experimental data on hematopoiesis in nonirradiated and irradiated mice, as well as on mortality dynamics of those in the absence of radiation are utilized. The life span probability and life span shortening predicted by the model agree with corresponding experimental data. Modeling results show the significance of ac- counting the variability of the individual radiosensitivity of critical system cells when estimating the radiation risk. These findings are corroborated by clinical data on persons involved in the elimination of the Chernobyl catastrophe after- effects. All this makes it feasible to use the model for radiation risk assessments for cosmonauts and astronauts on long-term missions such as a voyage to Mars or a lunar colony. In this case the model coefficients have to be determined by making use of the available data for humans. Scenarios for the dynamics of dose accumulation during space flights should also be taken into account.

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

    Science.gov (United States)

    Wong, Kin Fai Ellick; Kwong, Jessica Y Y

    2005-03-01

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

  15. Conceptual Models of the Individual Public Service Provider

    DEFF Research Database (Denmark)

    Andersen, Lotte Bøgh; Pedersen, Lene Holm; Bhatti, Yosef

    are used to gain insight on the motivation of public service providers; namely principal-agent theory, self-determination theory and public service motivation theory. We situate the theoretical discussions in the context of public service providers being transferred to private organizations......Individual public service providers’ motivation can be conceptualized as either extrinsic, autonomous or prosocial, and the question is how we can best theoretically understand this complexity without losing too much coherence and parsimony. Drawing on Allison’s approach (1969), three perspectives...... theoretical – to develop a coherent model of individual public service providers – but the empirical illustration also contributes to our understanding of motivation in the context of public sector outsourcing....

  16. Quality Assurance in Individual Monitoring: 10 Years of Performance Monitoring of the TLD Based TNO Individual Monitoring Service (invited paper)

    International Nuclear Information System (INIS)

    Dijk, J.W.E. van

    1998-01-01

    The QA subscription forms the nucleus of the Quality Assurance (QA) programme of the TLD-based Individual Monitoring Service of TNO-CSD. This QA subscription is the subscription of a dummy customer to the service. As this customer is treated exactly like a normal customer, all aspects of the service are monitored by the QA subscription. An overview is given of 10 years of monitoring the performance of the service. Various improvements over the past decade have resulted in a standard deviation in a low dose measurement of 0.01 mSv and a relative standard deviation at higher doses of 5%. These figures represent the performance under routine circumstances and thus include variations due to variations in the natural background from place to place and, for example, due to transport. (author)

  17. Quality Assurance in Individual Monitoring: 10 Years of Performance Monitoring of the TLD Based TNO Individual Monitoring Service (invited paper)

    Energy Technology Data Exchange (ETDEWEB)

    Dijk, J.W.E. van

    1998-07-01

    The QA subscription forms the nucleus of the Quality Assurance (QA) programme of the TLD-based Individual Monitoring Service of TNO-CSD. This QA subscription is the subscription of a dummy customer to the service. As this customer is treated exactly like a normal customer, all aspects of the service are monitored by the QA subscription. An overview is given of 10 years of monitoring the performance of the service. Various improvements over the past decade have resulted in a standard deviation in a low dose measurement of 0.01 mSv and a relative standard deviation at higher doses of 5%. These figures represent the performance under routine circumstances and thus include variations due to variations in the natural background from place to place and, for example, due to transport. (author)

  18. Mechanisms underlying the bioindicator notion: spatial association between individual sexual performance and community diversity.

    Directory of Open Access Journals (Sweden)

    Paola Laiolo

    Full Text Available The bioindicator notion is an appealing concept that has received more support in applied than in basic ecology, mostly due to the difficulty in deriving general ecological rules applicable to all target organisms. However, recognizing the mechanisms that determine the association between a particular species and the well-being of many other species is important for understanding the functioning of ecosystems and the relationship among different biological levels. We examined here the processes at the individual level that cause an association between species performance and biodiversity value, by analyzing attributes that can be studied in a variety of animals with sexual reproduction, namely breeding site selection and condition-dependent sexual signals. Our study model was the Capercaillie, an indicator of forest functioning and diversity, and the associated bird community, used here as a surrogate of broader forest biodiversity. At a regional scale Capercaillie occurrence was not associated with the most diverse forest patches, but at the scale of male spring territories the sexual display grounds (arenas were located in the oldest and less disturbed forest portions, which also hosted the richest local bird communities. Social mechanisms and conspecific cueing likely concurred with habitat-driven processes in determining the long-term persistence of traditional display grounds, which were appealing to many other species because of their structural composition. Characteristics of male vocal display that honestly advertize male quality (low frequencies and rapid song rates were significantly correlated with high diversity values, resulting in a spatial association between individual and community performances. Costly or risky activities such as reproductive or social behaviors, which more than other attributes match gradients in habitat quality, are therefore contributing to functionally connect individuals with ecosystem health.

  19. Individual-based modeling of fish: Linking to physical models and water quality.

    Energy Technology Data Exchange (ETDEWEB)

    Rose, K.A.

    1997-08-01

    The individual-based modeling approach for the simulating fish population and community dynamics is gaining popularity. Individual-based modeling has been used in many other fields, such as forest succession and astronomy. The popularity of the individual-based approach is partly a result of the lack of success of the more aggregate modeling approaches traditionally used for simulating fish population and community dynamics. Also, recent recognition that it is often the atypical individual that survives has fostered interest in the individual-based approach. Two general types of individual-based models are distribution and configuration. Distribution models follow the probability distributions of individual characteristics, such as length and age. Configuration models explicitly simulate each individual; the sum over individuals being the population. DeAngelis et al (1992) showed that, when distribution and configuration models were formulated from the same common pool of information, both approaches generated similar predictions. The distribution approach was more compact and general, while the configuration approach was more flexible. Simple biological changes, such as making growth rate dependent on previous days growth rates, were easy to implement in the configuration version but prevented simple analytical solution of the distribution version.

  20. The relationship between line manager behavior, perceived HRM practices and individual performance : Examining the mediating role of engagement

    NARCIS (Netherlands)

    Alfes, K.; Truss, C.; Soane, E.; Rees, C.; Gatenby, M.

    2013-01-01

    This article examines the role played by line managers in the link between HRM practices and individual performance outcomes. Drawing on social exchange theory, the authors test a mediated model linking perceived line manager behavior and perceived human resource management practices with employee

  1. Analytical models approximating individual processes: a validation method.

    Science.gov (United States)

    Favier, C; Degallier, N; Menkès, C E

    2010-12-01

    Upscaling population models from fine to coarse resolutions, in space, time and/or level of description, allows the derivation of fast and tractable models based on a thorough knowledge of individual processes. The validity of such approximations is generally tested only on a limited range of parameter sets. A more general validation test, over a range of parameters, is proposed; this would estimate the error induced by the approximation, using the original model's stochastic variability as a reference. This method is illustrated by three examples taken from the field of epidemics transmitted by vectors that bite in a temporally cyclical pattern, that illustrate the use of the method: to estimate if an approximation over- or under-fits the original model; to invalidate an approximation; to rank possible approximations for their qualities. As a result, the application of the validation method to this field emphasizes the need to account for the vectors' biology in epidemic prediction models and to validate these against finer scale models. Copyright © 2010 Elsevier Inc. All rights reserved.

  2. Using ROC curves to compare neural networks and logistic regression for modeling individual noncatastrophic tree mortality

    Science.gov (United States)

    Susan L. King

    2003-01-01

    The performance of two classifiers, logistic regression and neural networks, are compared for modeling noncatastrophic individual tree mortality for 21 species of trees in West Virginia. The output of the classifier is usually a continuous number between 0 and 1. A threshold is selected between 0 and 1 and all of the trees below the threshold are classified as...

  3. Modelling collective foraging by means of individual behaviour rules in honey-bees

    NARCIS (Netherlands)

    Vries, Han de; Biesmeijer, J.C.

    1998-01-01

    An individual-oriented model is constructed which simulates the collective foraging behaviour of a colony of honey-bees, Apis mellifera. Each bee follows the same set of behavioural rules. Each rule consists of a set of conditions followed by the behavioural act to be performed if the

  4. Modelling collective foraging by means of individual behaviour rules in honey-bees

    NARCIS (Netherlands)

    de Vries, H; Biesmeijer, JC

    1998-01-01

    An individual-oriented model is constructed which simulates the collective foraging behaviour of a colony of honey-bees, Apis mellifera. Each bee follows the same set of behavioural rules. Each rule consists of a set of conditions followed by the behavioural act to be performed if the conditions are

  5. Modeling Structural, Dyadic, and Individual Factors: The Inclusion and Exclusion Model of HIV Related Behavior

    OpenAIRE

    Albarracin, Dolores; Tannenbaum, Melanie B.; Glasman, Laura R.; Rothman, Alexander J.

    2010-01-01

    Changing HIV-related behaviors requires addressing the individual, dyadic, and structural influences that shape them. This supplement of AIDS & Behavior presents frameworks that integrate these three influences on behavior. Concepts from these frameworks were selected to model the processes by which structural factors affect individual HIV-related behavior. In the Inclusion/Exclusion Model, material and symbolic inclusions and exclusions (sharing versus denying resources) regulate individuals...

  6. Calibration of PMIS pavement performance prediction models.

    Science.gov (United States)

    2012-02-01

    Improve the accuracy of TxDOTs existing pavement performance prediction models through calibrating these models using actual field data obtained from the Pavement Management Information System (PMIS). : Ensure logical performance superiority patte...

  7. Using decision models to enhance investigations of individual differences in cognitive neuroscience

    Directory of Open Access Journals (Sweden)

    Corey N White

    2016-02-01

    Full Text Available There is great interest in relating individual differences in cognitive processing to activation of neural systems. The general process involves relating measures of task performance like reaction times or accuracy to brain activity to identify individual differences in neural processing. One limitation of this approach is that measures like reaction times can be affected by multiple components of processing. For instance, some individuals might have higher accuracy in a memory task because they respond more cautiously, not because they have better memory. Computational models of decision making, like the drift-diffusion model and the linear ballistic accumulator model, provide a potential solution to this problem. They can be fitted to data from individual participants to disentangle the effects of the different processes driving behavior. In this sense the models can provide cleaner measures of the processes of interest, and enhance our understanding of how neural activity varies across individuals or populations. The advantages of this model-based approach to investigating individual differences in neural activity are discussed with recent examples of how this method can improve our understanding of the brain-behavior relationship.

  8. Individual acceptance of the biogas innovation: A structural equation model

    International Nuclear Information System (INIS)

    Emmann, Carsten H.; Arens, Ludwig; Theuvsen, Ludwig

    2013-01-01

    The rapid spread of biogas production in Germany has resulted in an increased public debate over this new business branch. Today the production of biogas is much more controversially debated than several years ago. At the same time it could be proven that even among farmers themselves the acceptance of biogas production in some regions is somewhat dampened due to accompanying “collateral damages”. Therefore, the goal of this paper is to identify relevant influencing factors that determine the acceptance of the innovation “biogas” among farmers by applying a causal analysis. Initial results among the five investigated determinants show that not only an individual attitude toward biogas but also the farmers' personal innovativeness strongly and significantly influences an individual's acceptance of the innovation “biogas”. -- Highlights: •Strong expansion of biogas production based on renewable resources in Germany since 2004. •Low acceptance of biogas production in some regions. •Identification of influencing factors that determine the individual acceptance of the biogas innovation among German farmers. •Compared to existing studies, personal innovativeness was taken into account in the causal model. •Results are important for the further expansion of biogas production in Germany as well as in other countries

  9. An individual reproduction model sensitive to milk yield and body condition in Holstein dairy cows.

    Science.gov (United States)

    Brun-Lafleur, L; Cutullic, E; Faverdin, P; Delaby, L; Disenhaus, C

    2013-08-01

    To simulate the consequences of management in dairy herds, the use of individual-based herd models is very useful and has become common. Reproduction is a key driver of milk production and herd dynamics, whose influence has been magnified by the decrease in reproductive performance over the last decades. Moreover, feeding management influences milk yield (MY) and body reserves, which in turn influence reproductive performance. Therefore, our objective was to build an up-to-date animal reproduction model sensitive to both MY and body condition score (BCS). A dynamic and stochastic individual reproduction model was built mainly from data of a single recent long-term experiment. This model covers the whole reproductive process and is composed of a succession of discrete stochastic events, mainly calving, ovulations, conception and embryonic loss. Each reproductive step is sensitive to MY or BCS levels or changes. The model takes into account recent evolutions of reproductive performance, particularly concerning calving-to-first ovulation interval, cyclicity (normal cycle length, prevalence of prolonged luteal phase), oestrus expression and pregnancy (conception, early and late embryonic loss). A sensitivity analysis of the model to MY and BCS at calving was performed. The simulated performance was compared with observed data from the database used to build the model and from the bibliography to validate the model. Despite comprising a whole series of reproductive steps, the model made it possible to simulate realistic global reproduction outputs. It was able to well simulate the overall reproductive performance observed in farms in terms of both success rate (recalving rate) and reproduction delays (calving interval). This model has the purpose to be integrated in herd simulation models to usefully test the impact of management strategies on herd reproductive performance, and thus on calving patterns and culling rates.

  10. Motor performance of individuals with cerebral palsy in a virtual game using a mobile phone.

    Science.gov (United States)

    de Paula, Juliana Nobre; de Mello Monteiro, Carlos Bandeira; da Silva, Talita Dias; Capelini, Camila Miliani; de Menezes, Lilian Del Cielo; Massetti, Thais; Tonks, James; Watson, Suzanna; Nicolai Ré, Alessandro Hervaldo

    2017-11-01

    Cerebral palsy (CP) is a permanent disorder of movement, muscle tone or posture that is caused by damage to the immature and developing brain. Research has shown that Virtual Reality (VR) technology can be used in rehabilitation to support the acquisition of motor skills and the achievement of functional tasks. The aim of this study was to explore for improvements in the performance of individuals with CP with practice in the use of a virtual game on a mobile phone and to compare their performance with that of the control group. Twenty-five individuals with CP were matched for age and sex with twenty-five, typically developing individuals. Participants were asked to complete a VR maze task as fast as possible on a mobile phone. All participants performed 20 repetitions in the acquisition phase, five repetitions for retention and five more repetitions for transfer tests, in order to evaluate motor learning from the task. The CP group improved their performance in the acquisition phase and maintained the performance, which was shown by the retention test; in addition, they were able to transfer the performance acquired in an opposite maze path. The CP group had longer task-execution compared to the control group for all phases of the study. Individuals with cerebral palsy were able to learn a virtual reality game (maze task) using a mobile phone, and despite their differences from the control group, this kind of device offers new possibilities for use to improve function. Implications for rehabilitation A virtual game on a mobile phone can enable individuals with Cerebral Palsy (CP) to improve performance. This illustrates the potential for use of mobile phone games to improve function. Individuals with CP had poorer performance than individuals without CP, but they demonstrated immediate improvements from using a mobile phone device. Individuals with CP were able to transfer their skills to a similar task indicating that they were able to learn these motor skills by

  11. Flexible working, individual performance and employee attitudes: comparing formal and informal arrangements

    OpenAIRE

    De Menezes, Lilian M.; Kelliher, Clare

    2016-01-01

    In the context of a wider trend to individualize HRM, this paper examines the relationship between flexible working arrangements and individual performance. Drawing on a range of theories, it examines potential indirect effects on employee performance via job satisfaction and organizational commitment and analyses whether these relationships vary according to whether the arrangement was set up through a formal process, or negotiated informally between the employee and their line manager. Exta...

  12. Memory for self-performed actions in individuals with Asperger syndrome.

    OpenAIRE

    Tiziana Zalla; Elena Daprati; Anca-Maria Sav; Pauline Chaste; Daniele Nico; Marion Leboyer

    2010-01-01

    Memory for action is enhanced if individuals are allowed to perform the corresponding movements, compared to when they simply listen to them (enactment effect). Previous studies have shown that individuals with Autism Spectrum Disorders (ASD) have difficulties with processes involving the self, such as autobiographical memories and self performed actions. The present study aimed at assessing memory for action in Asperger Syndrome (AS). We investigated whether adults with AS would benefit from...

  13. Developing of Individual Instrument Performance Anxiety Scale: ValidityReliability Study

    Directory of Open Access Journals (Sweden)

    Esra DALKIRAN

    2016-07-01

    Full Text Available In this study, it is intended to develop a scale unique to our culture, concerning individual instrument performance anxiety of the students who are getting instrument training in the Department of Music Education. In the study, the descriptive research model is used and qualitative research techniques are utilized. The study population consists of the students attending the 23 universities which has Music Education Department. The sample of the study consists of 438 girls and 312 boys, totally 750 students who are studying in the Department of Music Education of randomly selected 10 universities. As a result of the explanatory and confirmatory factor analyses that were performed, a onedimensional structure consisting of 14 items was obtained. Also, t-scores and the coefficient scores of total item correlation concerning the distinguishing power of the items, the difference in the scores of the set of lower and upper 27% was calculated, and it was observed that the items are distinguishing as a result of both analyses. Of the scale, Cronbach's alpha coefficient of internal consistency was calculated as .94, and test-retest reliability coefficient was calculated as .93. As a result, a valid and reliable assessment and evaluation instrument that measures the exam performance anxiety of the students studying in the Department of Music Education, has been developed.

  14. Functional capacity evaluation of work performance among individuals with pelvic injuries following motor vehicle accidents.

    Science.gov (United States)

    Ratzon, Navah Z; Ari Shevil, Eynat Ben; Froom, Paul; Friedman, Sharon; Amit, Yehuda

    2013-01-01

    Pelvic injuries following motor vehicle accidents (MVA) cause disability and affect work capabilities. This study evaluated functional, self-report, and medical-based factors that could predict work capacity as was reflected in a functional capacity evaluation (FCE) among persons who sustained a pelvic injury. It was hypothesized that self-reported functional status and bio-demographic variables would predict work capacity. Sixty-one community-dwelling adults previously hospitalized following a MVA induced pelvic injury. FCE for work performance was conducted using the Physical Work Performance Evaluation (PWPE). Additional data was collected through a demographics questionnaire and the Functional Status Questionnaire. All participants underwent an orthopedic medical examination of the hip and lower extremities. Most participants self-reported that their work capacity post-injury were lower than their job required. PWPE scores indicated below-range functional performance. Regression models predicted 23% to 51% of PWPE subtests. Participants' self-report of functioning (instrumental activities of daily living and work) and bio-demographic variables (gender and age) were better predictors of PWPE scores than factors originating from the medical examination. Results support the inclusion of FCE, in addition to self-report of functioning and medical examination, to evaluate work capacity among individuals' post-pelvic injury and interventions and discharge planning.

  15. An individual reproduction model sensitive to milk yield and body condition in Holstein dairy cows

    OpenAIRE

    Brun-Lafleur, L.; Cutullic, E.; Faverdin, P.; Delaby, L.; Disenhaus, C.

    2017-01-01

    To simulate the consequences of management in dairy herds, the use of individual-based herd models is very useful and has become common. Reproduction is a key driver of milk production and herd dynamics, whose influence has been magnified by the decrease in reproductive performance over the last decades. Moreover, feeding management influences milk yield (MY) and body reserves, which in turn influence reproductive performance. Therefore, our objective was to build an up-to-date animal reprodu...

  16. Unlocking the forest inventory data: relating individual tree performance to unmeasured environmental factors

    Science.gov (United States)

    Jeremy W. Lichstein; Jonathan Dushoff; Kiona Ogle; Anping Chen; Drew W. Purves; John P. Caspersen; Stephen W. Pacala

    2010-01-01

    Geographically extensive forest inventories, such as the USDA Forest Service's Forest Inventory and Analysis (FIA) program, contain millions of individual tree growth and mortality records that could be used to develop broad-scale models of forest dynamics. A limitation of inventory data, however, is that individual-level measurements of light (L) and other...

  17. Classification Systems for Individual Differences in Multiple-task Performance and Subjective Estimates of Workload

    Science.gov (United States)

    Damos, D. L.

    1984-01-01

    Human factors practitioners often are concerned with mental workload in multiple-task situations. Investigations of these situations have demonstrated repeatedly that individuals differ in their subjective estimates of workload. These differences may be attributed in part to individual differences in definitions of workload. However, after allowing for differences in the definition of workload, there are still unexplained individual differences in workload ratings. The relation between individual differences in multiple-task performance, subjective estimates of workload, information processing abilities, and the Type A personality trait were examined.

  18. Performance Modelling of Steam Turbine Performance using Fuzzy ...

    African Journals Online (AJOL)

    Performance Modelling of Steam Turbine Performance using Fuzzy Logic ... AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING AJOL · RESOURCES. Journal of Applied Sciences and Environmental Management ... A Fuzzy Inference System for predicting the performance of steam turbine

  19. Modeling structured population dynamics using data from unmarked individuals

    Science.gov (United States)

    Grant, Evan H. Campbell; Zipkin, Elise; Thorson, James T.; See, Kevin; Lynch, Heather J.; Kanno, Yoichiro; Chandler, Richard; Letcher, Benjamin H.; Royle, J. Andrew

    2014-01-01

    The study of population dynamics requires unbiased, precise estimates of abundance and vital rates that account for the demographic structure inherent in all wildlife and plant populations. Traditionally, these estimates have only been available through approaches that rely on intensive mark–recapture data. We extended recently developed N-mixture models to demonstrate how demographic parameters and abundance can be estimated for structured populations using only stage-structured count data. Our modeling framework can be used to make reliable inferences on abundance as well as recruitment, immigration, stage-specific survival, and detection rates during sampling. We present a range of simulations to illustrate the data requirements, including the number of years and locations necessary for accurate and precise parameter estimates. We apply our modeling framework to a population of northern dusky salamanders (Desmognathus fuscus) in the mid-Atlantic region (USA) and find that the population is unexpectedly declining. Our approach represents a valuable advance in the estimation of population dynamics using multistate data from unmarked individuals and should additionally be useful in the development of integrated models that combine data from intensive (e.g., mark–recapture) and extensive (e.g., counts) data sources.

  20. Individual reactions to stress predict performance during a critical aviation incident.

    Science.gov (United States)

    Vine, Samuel J; Uiga, Liis; Lavric, Aureliu; Moore, Lee J; Tsaneva-Atanasova, Krasimira; Wilson, Mark R

    2015-01-01

    Understanding the influence of stress on human performance is of theoretical and practical importance. An individual's reaction to stress predicts their subsequent performance; with a "challenge" response to stress leading to better performance than a "threat" response. However, this contention has not been tested in truly stressful environments with highly skilled individuals. Furthermore, the effect of challenge and threat responses on attentional control during visuomotor tasks is poorly understood. Thus, this study aimed to examine individual reactions to stress and their influence on attentional control, among a cohort of commercial pilots performing a stressful flight assessment. Sixteen pilots performed an "engine failure on take-off" scenario, in a high-fidelity flight simulator. Reactions to stress were indexed via self-report; performance was assessed subjectively (flight instructor assessment) and objectively (simulator metrics); gaze behavior data were captured using a mobile eye tracker, and measures of attentional control were subsequently calculated (search rate, stimulus driven attention, and entropy). Hierarchical regression analyses revealed that a threat response was associated with poorer performance and disrupted attentional control. The findings add to previous research showing that individual reactions to stress influence performance and shed light on the processes through which stress influences performance.

  1. Biomechanical Evaluations of Hip Fracture Using Finite Element Model that Models Individual Differences of Femur

    OpenAIRE

    田中, 英一; TANAKA, Eiichi; 山本, 創太; YAMAMOTO, Sota; 坂本, 誠二; SAKAMOTO, Seiji; 中西, 孝文; NAKANISHI, Takafumi; 原田, 敦; HARADA, Atsushi; 水野, 雅士; MIZUNO, Masashi

    2004-01-01

    This paper is concerned with an individual finite element modeling system for femur and biomechanical evaluations of the influences of loading conditions, bone shape and bone density on risks of hip fracture. Firstly, a method to construct an individual finite element model by morphological parameters that represent femoral shapes was developed. Using the models with different shapes constructed by this method, the effects of fall direction, posture of upper body, femur shape and bone density...

  2. Validation of simplified centre of mass models during gait in individuals with chronic stroke.

    Science.gov (United States)

    Huntley, Andrew H; Schinkel-Ivy, Alison; Aqui, Anthony; Mansfield, Avril

    2017-10-01

    The feasibility of using a multiple segment (full-body) kinematic model in clinical gait assessment is difficult when considering obstacles such as time and cost constraints. While simplified gait models have been explored in healthy individuals, no such work to date has been conducted in a stroke population. The aim of this study was to quantify the errors of simplified kinematic models for chronic stroke gait assessment. Sixteen individuals with chronic stroke (>6months), outfitted with full body kinematic markers, performed a series of gait trials. Three centre of mass models were computed: (i) 13-segment whole-body model, (ii) 3 segment head-trunk-pelvis model, and (iii) 1 segment pelvis model. Root mean squared error differences were compared between models, along with correlations to measures of stroke severity. Error differences revealed that, while both models were similar in the mediolateral direction, the head-trunk-pelvis model had less error in the anteroposterior direction and the pelvis model had less error in the vertical direction. There was some evidence that the head-trunk-pelvis model error is influenced in the mediolateral direction for individuals with more severe strokes, as a few significant correlations were observed between the head-trunk-pelvis model and measures of stroke severity. These findings demonstrate the utility and robustness of the pelvis model for clinical gait assessment in individuals with chronic stroke. Low error in the mediolateral and vertical directions is especially important when considering potential stability analyses during gait for this population, as lateral stability has been previously linked to fall risk. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. The effect of individual characteristics of decision making and judgment on stock-flow performance

    NARCIS (Netherlands)

    Raaijmakers, S.; Korzilius, H.P.L.M.; Rouwette, E.A.J.A.; Vennix, J.A.M.

    2012-01-01

    Extending the line of research on stock-flow performance we examined the impact of personality characteristics on task performance. It was assumed that the need for cognition, the need for closure and the preference for intuition and deliberation would relate to individual variations in

  4. Job crafting at the team and individual level: Implications for work engagement and performance

    NARCIS (Netherlands)

    Tims, M.; Bakker, A.B.; Derks, D.; Rhenen, van W.

    2013-01-01

    Previous research suggests that employee job crafting is positively related to job performance through employee work engagement. The present study expands this individual-level perspective to the team level by hypothesizing that team job crafting relates positively to team performance through team

  5. Steady States in SIRS Epidemical Model of Mobile Individuals

    International Nuclear Information System (INIS)

    Zhang Duanming; He Minhua; Yu Xiaoling; Pan Guijun; Sun Hongzhang; Su Xiangying; Sun Fan; Yin Yanping; Li Rui; Liu Dan

    2006-01-01

    We consider an epidemical model within socially interacting mobile individuals to study the behaviors of steady states of epidemic propagation in 2D networks. Using mean-field approximation and large scale simulations, we recover the usual epidemic behavior with critical thresholds δ c and p c below which infectious disease dies out. For the population density δ far above δ c , it is found that there is linear relationship between contact rate λ and the population density δ in the main. At the same time, the result obtained from mean-field approximation is compared with our numerical result, and it is found that these two results are similar by and large but not completely the same.

  6. Steady States in SIRS Epidemical Model of Mobile Individuals

    Institute of Scientific and Technical Information of China (English)

    ZHANG Duan-Ming; LIU Dan; HE Min-Hua; YU Xiao-Ling; PAN Gui-Jun; SUN Hong-Zhang; SU Xiang-Ying; SUN Fan; YIN Yan-Ping; LI Rui

    2006-01-01

    We consider an epidemical model within socially interacting mobile individuals to study the behaviors of steady statesof epidemic propagation in 2D networks. Using mean-field approximation and large scale simulations, we recover the usual epidemic behavior with critical thresholds δc and pc below which infectious disease dies out. For the population density δ far above δc, it is found that there is linear relationship between contact rate λ and the population density δ in the main. At the same time, the result obtained from mean-field approximation is compared with our numerical result, and it is found that these two results are similar by and large but not completely the same.

  7. A model of individualized canonical microcircuits supporting cognitive operations.

    Directory of Open Access Journals (Sweden)

    Tim Kunze

    Full Text Available Major cognitive functions such as language, memory, and decision-making are thought to rely on distributed networks of a large number of basic elements, called canonical microcircuits. In this theoretical study we propose a novel canonical microcircuit model and find that it supports two basic computational operations: a gating mechanism and working memory. By means of bifurcation analysis we systematically investigate the dynamical behavior of the canonical microcircuit with respect to parameters that govern the local network balance, that is, the relationship between excitation and inhibition, and key intrinsic feedback architectures of canonical microcircuits. We relate the local behavior of the canonical microcircuit to cognitive processing and demonstrate how a network of interacting canonical microcircuits enables the establishment of spatiotemporal sequences in the context of syntax parsing during sentence comprehension. This study provides a framework for using individualized canonical microcircuits for the construction of biologically realistic networks supporting cognitive operations.

  8. Study on individual stochastic model of GNSS observations for precise kinematic applications

    Science.gov (United States)

    Próchniewicz, Dominik; Szpunar, Ryszard

    2015-04-01

    The proper definition of mathematical positioning model, which is defined by functional and stochastic models, is a prerequisite to obtain the optimal estimation of unknown parameters. Especially important in this definition is realistic modelling of stochastic properties of observations, which are more receiver-dependent and time-varying than deterministic relationships. This is particularly true with respect to precise kinematic applications which are characterized by weakening model strength. In this case, incorrect or simplified definition of stochastic model causes that the performance of ambiguity resolution and accuracy of position estimation can be limited. In this study we investigate the methods of describing the measurement noise of GNSS observations and its impact to derive precise kinematic positioning model. In particular stochastic modelling of individual components of the variance-covariance matrix of observation noise performed using observations from a very short baseline and laboratory GNSS signal generator, is analyzed. Experimental test results indicate that the utilizing the individual stochastic model of observations including elevation dependency and cross-correlation instead of assumption that raw measurements are independent with the same variance improves the performance of ambiguity resolution as well as rover positioning accuracy. This shows that the proposed stochastic assessment method could be a important part in complex calibration procedure of GNSS equipment.

  9. Long-term and within-day variability of working memory performance and EEG in individuals.

    Science.gov (United States)

    Gevins, Alan; McEvoy, Linda K; Smith, Michael E; Chan, Cynthia S; Sam-Vargas, Lita; Baum, Cliff; Ilan, Aaron B

    2012-07-01

    Assess individual-subject long-term and within-day variability of a combined behavioral and EEG test of working memory. EEGs were recorded from 16 adults performing n-back working memory tasks, with 10 tested in morning and afternoon sessions over several years. Participants were also tested after ingesting non-prescription medications or recreational substances. Performance and EEG measures were analyzed to derive an Overall score and three constituent sub-scores characterizing changes in performance, cortical activation, and alertness from each individual's baseline. Long-term and within-day variability were determined for each score; medication effects were assessed by reference to each individual's normal day-to-day variability. Over the several year period, the mean Overall score and sub-scores were approximately zero with standard deviations less than one. Overall scores were lower and their variability higher in afternoon relative to morning sessions. At the group level, alcohol, diphenhydramine and marijuana produced significant effects, but there were large individual differences. Objective working memory measures incorporating performance and EEG are stable over time and sensitive at the level of individual subjects to interventions that affect neurocognitive function. With further research these measures may be suitable for use in individualized medical care by providing a sensitive assessment of incipient illness and response to treatment. Published by Elsevier Ireland Ltd.

  10. Identification of Resilient Individuals and Those at Risk for Performance Deficits under Stress

    Directory of Open Access Journals (Sweden)

    Brent eWinslow

    2015-09-01

    Full Text Available Human task performance is affected by exposure to physiological and psychological stress. The ability to measure the physiological response to stressors and correlate that to task performance could be used to identify resilient individuals or those at risk for stress-related performance decrements. Accomplishing this prior to performance under severe stress or the development of clinical stress disorders could facilitate focused preparation such as tailoring training to individual needs. Here we measure the effects of stress on physiological response and performance through behavior, physiological sensors, and subjective ratings, and identify which individuals are at risk for stress-related performance decrements. Participants performed military-relevant training tasks under stress in a virtual environment, with autonomic and hypothalamic-pituitary-adrenal axis (HPA reactivity analyzed. Self-reported stress, as well as physiological indices of stress, increased in the group pre-exposed to socioevaluative stress. Stress response was effectively captured via electrodermal and cardiovascular measures of heart rate and skin conductance level. A resilience classification algorithm was developed based upon physiological reactivity, which correlated with baseline unstressed physiological and self-reported stress values. Outliers were identified in the experimental group that had a significant mismatch between self-reported stress and salivary cortisol. Baseline stress measurements were predictive of individual resilience to stress, including the impact stress had on physiological reactivity and performance. Such an approach may have utility in identifying individuals at risk for problems performing under severe stress. Continuing work has focused on adapting this method for military personnel, and assessing the utility of various coping and decision-making strategies on performance and physiological stress.

  11. Identification of resilient individuals and those at risk for performance deficits under stress.

    Science.gov (United States)

    Winslow, Brent D; Carroll, Meredith B; Martin, Jonathan W; Surpris, Glenn; Chadderdon, George L

    2015-01-01

    Human task performance is affected by exposure to physiological and psychological stress. The ability to measure the physiological response to stressors and correlate that to task performance could be used to identify resilient individuals or those at risk for stress-related performance decrements. Accomplishing this prior to performance under severe stress or the development of clinical stress disorders could facilitate focused preparation such as tailoring training to individual needs. Here we measure the effects of stress on physiological response and performance through behavior, physiological sensors, and subjective ratings, and identify which individuals are at risk for stress-related performance decrements. Participants performed military-relevant training tasks under stress in a virtual environment, with autonomic and hypothalamic-pituitary-adrenal axis (HPA) reactivity analyzed. Self-reported stress, as well as physiological indices of stress, increased in the group pre-exposed to socioevaluative stress. Stress response was effectively captured via electrodermal and cardiovascular measures of heart rate and skin conductance level. A resilience classification algorithm was developed based upon physiological reactivity, which correlated with baseline unstressed physiological and self-reported stress values. Outliers were identified in the experimental group that had a significant mismatch between self-reported stress and salivary cortisol. Baseline stress measurements were predictive of individual resilience to stress, including the impact stress had on physiological reactivity and performance. Such an approach may have utility in identifying individuals at risk for problems performing under severe stress. Continuing work has focused on adapting this method for military personnel, and assessing the utility of various coping and decision-making strategies on performance and physiological stress.

  12. Team performance modeling for HRA in dynamic situations

    International Nuclear Information System (INIS)

    Shu Yufei; Furuta, Kazuo; Kondo, Shunsuke

    2002-01-01

    This paper proposes a team behavior network model that can simulate and analyze response of an operator team to an incident in a dynamic and context-sensitive situation. The model is composed of four sub-models, which describe the context of team performance. They are task model, event model, team model and human-machine interface model. Each operator demonstrates aspects of his/her specific cognitive behavior and interacts with other operators and the environment in order to deal with an incident. Individual human factors, which determine the basis of communication and interaction between individuals, and cognitive process of an operator, such as information acquisition, state-recognition, decision-making and action execution during development of an event scenario are modeled. A case of feed and bleed operation in pressurized water reactor under an emergency situation was studied and the result was compared with an experiment to check the validity of the proposed model

  13. Photovoltaic array performance simulation models

    Energy Technology Data Exchange (ETDEWEB)

    Menicucci, D. F.

    1986-09-15

    The experience of the solar industry confirms that, despite recent cost reductions, the profitability of photovoltaic (PV) systems is often marginal and the configuration and sizing of a system is a critical problem for the design engineer. Construction and evaluation of experimental systems are expensive and seldom justifiable. A mathematical model or computer-simulation program is a desirable alternative, provided reliable results can be obtained. Sandia National Laboratories, Albuquerque (SNLA), has been studying PV-system modeling techniques in an effort to develop an effective tool to be used by engineers and architects in the design of cost-effective PV systems. This paper reviews two of the sources of error found in previous PV modeling programs, presents the remedies developed to correct these errors, and describes a new program that incorporates these improvements.

  14. Role of Leadership and Employee Engagement towards Individual Performance of Pharmacy Employees

    Directory of Open Access Journals (Sweden)

    Susi A. Rahayu

    2012-09-01

    Full Text Available Employees dissatisfaction to the head of the hospital pharmacy will decrease employees performance and unsatisfied customers. To solve the problems, employees should be based on performance as customer expectations in providing services. One of the ways to improve the performance of the employees, they must feel engage to the work. One of the factors to improve employee engagement is the leadership factor. Therefore, it is necessary to study the impact of leadership on individual performance employee in hospital pharmacy and also the influence of employee engagement as a mediator. A total of 79 employees from the pharmacy in two private hospitals in Bandung became the participants. This study used the technique of partial least squares to test the hypothesized relationships. The results showed that there were significant between leadership to employee engagement (t value (12,84 > t-table (1.64, the significance of employee engagement on individual performance (t value (3.83 > t-table (1.64. In contrast, there was no influence and significance in leadership on individual performance (t value (0.45 < t-table (1.64. Employee engagement fully mediated the relationship between leadership and individual performance. Therefore, improving pharmacy services is a set of actions and involvement of pharmacy employees who are consistent, sustainable and clear.

  15. Face recognition performance of individuals with Asperger syndrome on the Cambridge Face Memory Test.

    Science.gov (United States)

    Hedley, Darren; Brewer, Neil; Young, Robyn

    2011-12-01

    Although face recognition deficits in individuals with Autism Spectrum Disorder (ASD), including Asperger syndrome (AS), are widely acknowledged, the empirical evidence is mixed. This in part reflects the failure to use standardized and psychometrically sound tests. We contrasted standardized face recognition scores on the Cambridge Face Memory Test (CFMT) for 34 individuals with AS with those for 42, IQ-matched non-ASD individuals, and age-standardized scores from a large Australian cohort. We also examined the influence of IQ, autistic traits, and negative affect on face recognition performance. Overall, participants with AS performed significantly worse on the CFMT than the non-ASD participants and when evaluated against standardized test norms. However, while 24% of participants with AS presented with severe face recognition impairment (>2 SDs below the mean), many individuals performed at or above the typical level for their age: 53% scored within +/- 1 SD of the mean and 9% demonstrated superior performance (>1 SD above the mean). Regression analysis provided no evidence that IQ, autistic traits, or negative affect significantly influenced face recognition: diagnostic group membership was the only significant predictor of face recognition performance. In sum, face recognition performance in ASD is on a continuum, but with average levels significantly below non-ASD levels of performance. Copyright © 2011, International Society for Autism Research, Wiley-Liss, Inc.

  16. Employee engagement, organisational performance and individual wellbeing: Exploring the evidence, developing the theory

    OpenAIRE

    Truss, C.; Shantz, A.; Soane, E.; Emma, C.; Alfes, K.; Delbridge, R.

    2013-01-01

    The development of mainstream human resource management (HRM) theory has long been concerned with how people management can enhance performance outcomes. It is only very recently that interest has been shown in the parallel stream of research on the link between employee engagement and performance, bringing the two together to suggest that engagement may constitute the mechanism through which HRM practices impact individual and organisational performance. However, engagement has emerged as a ...

  17. Understanding individual resilience in the workplace: the international collaboration of workforce resilience model.

    Science.gov (United States)

    Rees, Clare S; Breen, Lauren J; Cusack, Lynette; Hegney, Desley

    2015-01-01

    When not managed effectively, high levels of workplace stress can lead to several negative personal and performance outcomes. Some professional groups work in highly stressful settings and are therefore particularly at risk of conditions such as anxiety, depression, secondary traumatic stress, and burnout. However, some individuals are less affected by workplace stress and the associated negative outcomes. Such individuals have been described as "resilient." A number of studies have found relationships between levels of individual resilience and specific negative outcomes such as burnout and compassion fatigue. However, because psychological resilience is a multi-dimensional construct it is necessary to more clearly delineate it from other related and overlapping constructs. The creation of a testable theoretical model of individual workforce resilience, which includes both stable traits (e.g., neuroticism) as well as more malleable intrapersonal factors (e.g., coping style), enables information to be derived that can eventually inform interventions aimed at enhancing individual resilience in the workplace. The purpose of this paper is to introduce a new theoretical model of individual workforce resilience that includes several intrapersonal constructs known to be central in the appraisal of and response to stressors and that also overlap with the construct of psychological resilience. We propose a model in which psychological resilience is hypothesized to mediate the relationship between neuroticism, mindfulness, self-efficacy, coping, and psychological adjustment.

  18. Understanding Individual Resilience in the Workplace: The International Collaboration of Workforce Resilience (ICWR Model

    Directory of Open Access Journals (Sweden)

    Clare Samantha Rees

    2015-02-01

    Full Text Available When not managed effectively, high levels of workplace stress can lead to several negative personal and performance outcomes. Some professional groups work in highly stressful settings and are therefore particularly at risk of conditions such as anxiety, depression, secondary traumatic stress and burnout. However, some individuals are less affected by workplace stress and the associated negative outcomes. Such individuals have been described as ‘resilient’. A number of studies have found relationships between levels of individual resilience and specific negative outcomes such as burnout and compassion fatigue. However, because psychological resilience is a multi-dimensional construct it is necessary to more clearly delineate it from other related and overlapping constructs. The creation of a testable theoretical model of individual workforce resilience, which includes both stable traits (e.g. neuroticism as well as more malleable intrapersonal factors (e.g. coping style, enables information to be derived that can eventually inform interventions aimed at enhancing individual resilience in the workplace. The purpose of this paper is to introduce a new theoretical model of individual workforce resilience that includes several intrapersonal constructs known to be central in the appraisal of and response to stressors and that also overlap with the construct of psychological resilience. We propose a model in which psychological resilience is hypothesised to mediate the relationship between neuroticism, mindfulness, self-efficacy, coping and psychological adjustment.

  19. Maintenance Personnel Performance Simulation (MAPPS) model

    International Nuclear Information System (INIS)

    Siegel, A.I.; Bartter, W.D.; Wolf, J.J.; Knee, H.E.; Haas, P.M.

    1984-01-01

    A stochastic computer model for simulating the actions and behavior of nuclear power plant maintenance personnel is described. The model considers personnel, environmental, and motivational variables to yield predictions of maintenance performance quality and time to perform. The mode has been fully developed and sensitivity tested. Additional evaluation of the model is now taking place

  20. The Influence of Individual Personalities Towards Team Performance at PT. Bpr Prisma Dana Manado

    OpenAIRE

    Untu, Mario Rahmat

    2014-01-01

    In today€™s global and competitive environment, one of the more often debated issues in the study of organizational behavior is the effects of workforce diversity such as personality on team performance. Workforce diversity refers to employee€™s individual differences and similarities. It stands for individuality that includes personality, gender, race, nationality, ethnicity, region, income, marital status, work experience, perceptions among others. The purpose of this study was to examine h...

  1. Case management: a randomized controlled study comparing a neighborhood team and a centralized individual model.

    Science.gov (United States)

    Eggert, G M; Zimmer, J G; Hall, W J; Friedman, B

    1991-10-01

    This randomized controlled study compared two types of case management for skilled nursing level patients living at home: the centralized individual model and the neighborhood team model. The team model differed from the individual model in that team case managers performed client assessments, care planning, some direct services, and reassessments; they also had much smaller caseloads and were assigned a specific catchment area. While patients in both groups incurred very high estimated health services costs, the average annual cost during 1983-85 for team cases was 13.6 percent less than that of individual model cases. While the team cases were 18.3 percent less expensive among "old" patients (patients who entered the study from the existing ACCESS caseload), they were only 2.7 percent less costly among "new" cases. The lower costs were due to reductions in hospital days and home care. Team cases averaged 26 percent fewer hospital days per year and 17 percent fewer home health aide hours. Nursing home use was 48 percent higher for the team group than for the individual model group. Mortality was almost exactly the same for both groups during the first year (about 30 percent), but was lower for team patients during the second year (11 percent as compared to 16 percent). Probable mechanisms for the observed results are discussed.

  2. An individual-based probabilistic model for simulating fisheries population dynamics

    Directory of Open Access Journals (Sweden)

    Jie Cao

    2016-12-01

    Full Text Available The purpose of stock assessment is to support managers to provide intelligent decisions regarding removal from fish populations. Errors in assessment models may have devastating impacts on the population fitness and negative impacts on the economy of the resource users. Thus, accuracte estimations of population size, growth rates are critical for success. Evaluating and testing the behavior and performance of stock assessment models and assessing the consequences of model mis-specification and the impact of management strategies requires an operating model that accurately describe the dynamics of the target species, and can resolve spatial and seasonal changes. In addition, the most thorough evaluations of assessment models use an operating model that takes a different form than the assessment model. This paper presents an individual-based probabilistic model used to simulate the complex dynamics of populations and their associated fisheries. Various components of population dynamics are expressed as random Bernoulli trials in the model and detailed life and fishery histories of each individual are tracked over their life span. The simulation model is designed to be flexible so it can be used for different species and fisheries. It can simulate mixing among multiple stocks and link stock-recruit relationships to environmental factors. Furthermore, the model allows for flexibility in sub-models (e.g., growth and recruitment and model assumptions (e.g., age- or size-dependent selectivity. This model enables the user to conduct various simulation studies, including testing the performance of assessment models under different assumptions, assessing the impacts of model mis-specification and evaluating management strategies.

  3. Memory for self-performed actions in individuals with Asperger syndrome.

    Directory of Open Access Journals (Sweden)

    Tiziana Zalla

    2010-10-01

    Full Text Available Memory for action is enhanced if individuals are allowed to perform the corresponding movements, compared to when they simply listen to them (enactment effect. Previous studies have shown that individuals with Autism Spectrum Disorders (ASD have difficulties with processes involving the self, such as autobiographical memories and self performed actions. The present study aimed at assessing memory for action in Asperger Syndrome (AS. We investigated whether adults with AS would benefit from the enactment effect when recalling a list of previously performed items vs. items that were only visually and verbally experienced through three experimental tasks (Free Recall, Old/New Recognition and Source Memory. The results showed that while performance on Recognition and Source Memory tasks was preserved in individuals with AS, the enactment effect for self-performed actions was not consistently present, as revealed by the lower number of performed actions being recalled on the Free Recall test, as compared to adults with typical development. Subtle difficulties in encoding specific motor and proprioceptive signals during action execution in individuals with AS might affect retrieval of relevant personal episodic information. These disturbances might be associated to an impaired action monitoring system.

  4. Memory for self-performed actions in individuals with Asperger syndrome.

    Science.gov (United States)

    Zalla, Tiziana; Daprati, Elena; Sav, Anca-Maria; Chaste, Pauline; Nico, Daniele; Leboyer, Marion

    2010-10-12

    Memory for action is enhanced if individuals are allowed to perform the corresponding movements, compared to when they simply listen to them (enactment effect). Previous studies have shown that individuals with Autism Spectrum Disorders (ASD) have difficulties with processes involving the self, such as autobiographical memories and self performed actions. The present study aimed at assessing memory for action in Asperger Syndrome (AS). We investigated whether adults with AS would benefit from the enactment effect when recalling a list of previously performed items vs. items that were only visually and verbally experienced through three experimental tasks (Free Recall, Old/New Recognition and Source Memory). The results showed that while performance on Recognition and Source Memory tasks was preserved in individuals with AS, the enactment effect for self-performed actions was not consistently present, as revealed by the lower number of performed actions being recalled on the Free Recall test, as compared to adults with typical development. Subtle difficulties in encoding specific motor and proprioceptive signals during action execution in individuals with AS might affect retrieval of relevant personal episodic information. These disturbances might be associated to an impaired action monitoring system.

  5. Assembly line performance and modeling

    Science.gov (United States)

    Rane, Arun B.; Sunnapwar, Vivek K.

    2017-09-01

    Automobile sector forms the backbone of manufacturing sector. Vehicle assembly line is important section in automobile plant where repetitive tasks are performed one after another at different workstations. In this thesis, a methodology is proposed to reduce cycle time and time loss due to important factors like equipment failure, shortage of inventory, absenteeism, set-up, material handling, rejection and fatigue to improve output within given cost constraints. Various relationships between these factors, corresponding cost and output are established by scientific approach. This methodology is validated in three different vehicle assembly plants. Proposed methodology may help practitioners to optimize the assembly line using lean techniques.

  6. Visual determinants of reduced performance on the Stroop color-word test in normal aging individuals.

    Science.gov (United States)

    van Boxtel, M P; ten Tusscher, M P; Metsemakers, J F; Willems, B; Jolles, J

    2001-10-01

    It is unknown to what extent the performance on the Stroop color-word test is affected by reduced visual function in older individuals. We tested the impact of common deficiencies in visual function (reduced distant and close acuity, reduced contrast sensitivity, and color weakness) on Stroop performance among 821 normal individuals aged 53 and older. After adjustment for age, sex, and educational level, low contrast sensitivity was associated with more time needed on card I (word naming), red/green color weakness with slower card 2 performance (color naming), and reduced distant acuity with slower performance on card 3 (interference). Half of the age-related variance in speed performance was shared with visual function. The actual impact of reduced visual function may be underestimated in this study when some of this age-related variance in Stroop performance is mediated by visual function decrements. It is suggested that reduced visual function has differential effects on Stroop performance which need to be accounted for when the Stroop test is used both in research and in clinical settings. Stroop performance measured from older individuals with unknown visual status should be interpreted with caution.

  7. The Effects of Creatine Supplementation on Explosive Performance and Optimal Individual Postactivation Potentiation Time

    Directory of Open Access Journals (Sweden)

    Chia-Chi Wang

    2016-03-01

    Full Text Available Creatine plays an important role in muscle energy metabolism. Postactivation potentiation (PAP is a phenomenon that can acutely increase muscle power, but it is an individualized process that is influenced by muscle fatigue. This study examined the effects of creatine supplementation on explosive performance and the optimal individual PAP time during a set of complex training bouts. Thirty explosive athletes performed tests of back squat for one repetition maximum (1RM strength and complex training bouts for determining the individual optimal timing of PAP, height and peak power of a counter movement jump before and after the supplementation. Subjects were assigned to a creatine or placebo group and then consumed 20 g of creatine or carboxymethyl cellulose per day for six days. After the supplementation, the 1RM strength in the creatine group significantly increased (p < 0.05. The optimal individual PAP time in the creatine group was also significant earlier than the pre-supplementation and post-supplementation of the placebo group (p < 0.05. There was no significant difference in jump performance between the groups. This study demonstrates that creatine supplementation improves maximal muscle strength and the optimal individual PAP time of complex training but has no effect on explosive performance.

  8. Longitudinal intra and inter-individual variability in young swimmers performance and determinant factors

    OpenAIRE

    Morais, Jorge; Costa, Mário; Moreira, Marc; Forte, Pedro; Silva, António; Marinho, Daniel; Barbosa, Tiago

    2014-01-01

    The aim of study was to follow-up the intra-individual and inter-individual stability of talented swimmers’ performance and its anthropometrics, kinematics, hydrodynamics and efficiency during two competitive seasons. Thirty talented swimmers (14 boys: 12.33 ± 0.65 years; and 16 girls: 11.15 ± 0.55 years) were followed-up. Performance (100-m freestyle), anthropometrics (body mass, height, arm span, chest perimeter, trunk transverse surface area, hand and foot surface area), kinematics (stroke...

  9. International trade shows: Structure, strategy and performance of exhibitors at individual booths vs. joint booths

    DEFF Research Database (Denmark)

    Hansen, Kåre

    2000-01-01

    This paper examines differences in exhibitors who participate at international trade shows at joint booths and those who participate at individual booths. The structure, strategy, and trade show performance of exhibitors at joint booths and those at individual booths are analysed. The analysis...... implications for exhibitors at interna-tional trade shows and export marketing programmes and other marketing programmes offering services to international trade show exhibitors....... of exhibitors at the international food shows SIAL (Paris) and ANUGA (Cologne) showed several significant differences with regard to structure and strategy. However, no significant differences in the performance assessments between the two partici-pation modes were found. The findings have important...

  10. The effects of individual status and group performance on network ties among teammates in the National Basketball Association.

    Directory of Open Access Journals (Sweden)

    Jeremy Koster

    Full Text Available For individuals, status is derived both from their personal attributes and the groups with whom they are affiliated. Depending on the performance of their groups, the status of individuals may benefit or suffer from identifying closely with the group. When the group excels, high-status members potentially receive much of the credit and increased status. Conversely, high-status members of underperforming groups potentially suffer disproportionate declines in their status relative to the low-status group members. We therefore predict an interaction between group performance and individual status on the willingness to associate with the group and its members. We test our prediction by examining social media ties among teammates in the National Basketball Association. Specifically, we investigate the "following" ties of teammates on Twitter at the end of the 2014-2015 season. Elections to All-Star games are used to measure the status of players, and team performance is measured by recent success in the postseason playoffs. The results show that compared to high-status players on successful teams, high-status players on underperforming teams are less likely to follow their teammates. This result aligns with research on status inconsistency, suggesting that individuals deemphasize their group affiliation when it jeopardizes their individual status. An additional contribution is the advancement of the probit Social Relations Model for the analysis of binary ties in social networks.

  11. The effects of individual status and group performance on network ties among teammates in the National Basketball Association.

    Science.gov (United States)

    Koster, Jeremy; Aven, Brandy

    2018-01-01

    For individuals, status is derived both from their personal attributes and the groups with whom they are affiliated. Depending on the performance of their groups, the status of individuals may benefit or suffer from identifying closely with the group. When the group excels, high-status members potentially receive much of the credit and increased status. Conversely, high-status members of underperforming groups potentially suffer disproportionate declines in their status relative to the low-status group members. We therefore predict an interaction between group performance and individual status on the willingness to associate with the group and its members. We test our prediction by examining social media ties among teammates in the National Basketball Association. Specifically, we investigate the "following" ties of teammates on Twitter at the end of the 2014-2015 season. Elections to All-Star games are used to measure the status of players, and team performance is measured by recent success in the postseason playoffs. The results show that compared to high-status players on successful teams, high-status players on underperforming teams are less likely to follow their teammates. This result aligns with research on status inconsistency, suggesting that individuals deemphasize their group affiliation when it jeopardizes their individual status. An additional contribution is the advancement of the probit Social Relations Model for the analysis of binary ties in social networks.

  12. Explorations in combining cognitive models of individuals and system dynamics models of groups.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.

    2008-07-01

    This report documents a demonstration model of interacting insurgent leadership, military leadership, government leadership, and societal dynamics under a variety of interventions. The primary focus of the work is the portrayal of a token societal model that responds to leadership activities. The model also includes a linkage between leadership and society that implicitly represents the leadership subordinates as they directly interact with the population. The societal model is meant to demonstrate the efficacy and viability of using System Dynamics (SD) methods to simulate populations and that these can then connect to cognitive models depicting individuals. SD models typically focus on average behavior and thus have limited applicability to describe small groups or individuals. On the other hand, cognitive models readily describe individual behavior but can become cumbersome when used to describe populations. Realistic security situations are invariably a mix of individual and population dynamics. Therefore, the ability to tie SD models to cognitive models provides a critical capability that would be otherwise be unavailable.

  13. Individual differences in chronotypes associated with academic performance among Chilean University students.

    Science.gov (United States)

    Valladares, Macarena; Ramírez-Tagle, Rodrigo; Muñoz, Miss Alexandra; Obregón, Ana María

    2018-04-01

    A chronotype is an individual trait that determines circadian rhythm (dark/light cycle) characteristics, associated with bedtime, waking, and other daily activities. A chronotype is classified as morning, intermediate, and evening. The objective is to associate chronotypes with academic performance in university students. A cross-sectional study was performed to evaluate the chronotype of university students (n = 703) by Horne-Ostberg questionnaire and associated with academic performance. The group with higher GPAs had higher chronotype scores (p = 0.002). Morning and intermediate chronotypes exhibited better academic performance; however, more studies are necessary to determine the underlying causes, which could influence cognitive aspects.

  14. Using individual differences to predict job performance: correcting for direct and indirect restriction of range.

    Science.gov (United States)

    Sjöberg, Sofia; Sjöberg, Anders; Näswall, Katharina; Sverke, Magnus

    2012-08-01

    The present study investigates the relationship between individual differences, indicated by personality (FFM) and general mental ability (GMA), and job performance applying two different methods of correction for range restriction. The results, derived by analyzing meta-analytic correlations, show that the more accurate method of correcting for indirect range restriction increased the operational validity of individual differences in predicting job performance and that this increase primarily was due to general mental ability being a stronger predictor than any of the personality traits. The estimates for single traits can be applied in practice to maximize prediction of job performance. Further, differences in the relative importance of general mental ability in relation to overall personality assessment methods was substantive and the estimates provided enables practitioners to perform a correct utility analysis of their overall selection procedure. © 2012 The Authors. Scandinavian Journal of Psychology © 2012 The Scandinavian Psychological Associations.

  15. Ability of aphasic individuals to perform numerical processing and calculation tasks

    Directory of Open Access Journals (Sweden)

    Gabriela De Luccia

    2014-03-01

    Full Text Available Objective To compare performance on EC301 battery calculation task between aphasic subjects and normal controls of the same sex, age, and education. Method Thirty-two aphasic patients who had suffered a single left hemisphere stroke were evaluated. Forty-four healthy volunteers were also selected. All subjects underwent a comprehensive arithmetic battery to assess their numerical and calculation skills. Performances on numerical processing and calculation tasks were then analyzed. Results Aphasic individuals showed changes in their ability to perform numerical processing and calculation tasks that were not observed in the healthy population. Conclusion Compared with healthy subjects of the same age and education level, individuals with aphasia had difficulty performing various tasks that involved numerical processing and calculation.

  16. Why Are Some More Peer Than Others? Evidence from a Longitudinal Study of Social Networks and Individual Academic Performance.

    Science.gov (United States)

    Lomi, Alessandro; Snijders, Tom A B; Steglich, Christian E G; Torlo, Vanina Jasmine

    2011-11-01

    Studies of peer effects in educational settings confront two main problems. The first is the presence of endogenous sorting which confounds the effects of social influence and social selection on individual attainment. The second is how to account for the local network dependencies through which peer effects influence individual behavior. We empirically address these problems using longitudinal data on academic performance, friendship, and advice seeking relations among students in a full-time graduate academic program. We specify stochastic agent-based models that permit estimation of the interdependent contribution of social selection and social influence to individual performance. We report evidence of peer effects. Students tend to assimilate the average performance of their friends and of their advisors. At the same time, students attaining similar levels of academic performance are more likely to develop friendship and advice ties. Together, these results imply that processes of social influence and social selection are sub-components of a more general a co-evolutionary process linking network structure and individual behavior. We discuss possible points of contact between our findings and current research in the economics and sociology of education.

  17. Effects of sweeteners on individual feed intake characteristics and performance in group-housed weanling pigs

    NARCIS (Netherlands)

    Sterk, A.R.; Schlegel, P.; Mul, A.J.; Ubbink-Blanksma, M.; Bruininx, E.M.A.M.

    2008-01-01

    To assess the effects of 2 high intensity sodium saccharine based sweeteners on individual feed intake characteristics and performance of group-housed weaned pigs, 198 26-d-old weanling pigs were given ad libitum access to 3 dietary treatments: containing no additional sweetener (Control), 150 mg

  18. The Effects of Diversity Management on Job Satisfaction and Individual Performance of Teachers

    Science.gov (United States)

    Ordu, Aydan

    2016-01-01

    In this research, the effects of teachers' perceptions of the diversity management on their job satisfaction and individual performance were examined. Teachers who are working in public high schools during 2014 to 2015 academic year constituted the study group of the research. The data of the research in which quantitative method used were…

  19. Effects of Individual Characteristics on Expatriates' Adjustment and Job Performance

    Science.gov (United States)

    Bhatti, Muhammad Awais; Kaur, Sharan; Battour, Mohamed Mohamed

    2013-01-01

    Purpose: Researchers have been focusing on the predictors of expatriates' adjustment and job performance at different levels (individual level, organizational level and societal level), but still some of the predictors have been ignored or unclear in the expatriate literature. The purpose of this paper is to develop a comprehensive framework…

  20. The Impact of Individual, Competitive, and Collaborative Mathematics Game Play on Learning, Performance, and Motivation

    Science.gov (United States)

    Plass, Jan L.; O'Keefe, Paul A.; Homer, Bruce D.; Case, Jennifer; Hayward, Elizabeth O.; Stein, Murphy; Perlin, Ken

    2013-01-01

    The present research examined how mode of play in an educational mathematics video game impacts learning, performance, and motivation. The game was designed for the practice and automation of arithmetic skills to increase fluency and was adapted to allow for individual, competitive, or collaborative game play. Participants (N = 58) from urban…

  1. When and why creativity-related conflict with coworkers can hamper creative employees' individual job performance

    NARCIS (Netherlands)

    Janssen, Onne; Giebels, Ellen

    2013-01-01

    We examined when and why focal employees' creativity-related conflict with coworkers is related to their individual job performance. As hypothesized, a survey among 113 employees in 14 manufacturing work groups showed that creativity-related conflict with coworkers escalates into dysfunctional

  2. The Best and the Rest: Revisiting the Norm of Normality of Individual Performance

    Science.gov (United States)

    O'Boyle, Ernest, Jr.; Aguinis, Herman

    2012-01-01

    We revisit a long-held assumption in human resource management, organizational behavior, and industrial and organizational psychology that individual performance follows a Gaussian (normal) distribution. We conducted 5 studies involving 198 samples including 633,263 researchers, entertainers, politicians, and amateur and professional athletes.…

  3. SPSP Phase III Recruiting, Selecting, and Developing Secure Power Systems Professionals. Individual and Team Performance Guidelines

    Energy Technology Data Exchange (ETDEWEB)

    O' Neil, Lori Ross [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Conway, T. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tobey, D. H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Greitzer, Frank L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dalton, Angela C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Pusey, Portia K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-03-01

    The Secure Power Systems Professional Phase III final report was released last year which an appendix of Individual and Team Performance Guidelines. This new report is that appendix broken out as a standalone document to assist utilities in recruiting and developing Secure Power Systems Professionals at their site.

  4. A method to evaluate performance reliability of individual subjects in laboratory research applied to work settings.

    Science.gov (United States)

    1978-10-01

    This report presents a method that may be used to evaluate the reliability of performance of individual subjects, particularly in applied laboratory research. The method is based on analysis of variance of a tasks-by-subjects data matrix, with all sc...

  5. Individual Differences Influencing Immediate Effects of Internal and External Focus Instructions on Children's Motor Performance.

    Science.gov (United States)

    van Abswoude, Femke; Nuijen, Nienke B; van der Kamp, John; Steenbergen, Bert

    2018-06-01

    A large pool of evidence supports the beneficial effect of an external focus of attention on motor skill performance in adults. In children, this effect has been studied less and results are inconclusive. Importantly, individual differences are often not taken into account. We investigated the role of working memory, conscious motor control, and task-specific focus preferences on performance with an internal and external focus of attention in children. Twenty-five children practiced a golf putting task in both an internal focus condition and external focus condition. Performance was defined as the average distance toward the hole in 3 blocks of 10 trials. Task-specific focus preference was determined by asking how much effort it took to apply the instruction in each condition. In addition, working memory capacity and conscious motor control were assessed. Children improved performance in both the internal focus condition and external focus condition (ŋ p 2  = .47), with no difference between conditions (ŋ p 2  = .01). Task-specific focus preference was the only factor moderately related to the difference between performance with an internal focus and performance with an external focus (r = .56), indicating better performance for the preferred instruction in Block 3. Children can benefit from instruction with both an internal and external focus of attention to improve short-term motor performance. Individual, task-specific focus preference influenced the effect of the instructions, with children performing better with their preferred focus. The results highlight that individual differences are a key factor in the effectiveness in children's motor performance. The precise mechanisms underpinning this effect warrant further research.

  6. Work domain constraints for modelling surgical performance.

    Science.gov (United States)

    Morineau, Thierry; Riffaud, Laurent; Morandi, Xavier; Villain, Jonathan; Jannin, Pierre

    2015-10-01

    Three main approaches can be identified for modelling surgical performance: a competency-based approach, a task-based approach, both largely explored in the literature, and a less known work domain-based approach. The work domain-based approach first describes the work domain properties that constrain the agent's actions and shape the performance. This paper presents a work domain-based approach for modelling performance during cervical spine surgery, based on the idea that anatomical structures delineate the surgical performance. This model was evaluated through an analysis of junior and senior surgeons' actions. Twenty-four cervical spine surgeries performed by two junior and two senior surgeons were recorded in real time by an expert surgeon. According to a work domain-based model describing an optimal progression through anatomical structures, the degree of adjustment of each surgical procedure to a statistical polynomial function was assessed. Each surgical procedure showed a significant suitability with the model and regression coefficient values around 0.9. However, the surgeries performed by senior surgeons fitted this model significantly better than those performed by junior surgeons. Analysis of the relative frequencies of actions on anatomical structures showed that some specific anatomical structures discriminate senior from junior performances. The work domain-based modelling approach can provide an overall statistical indicator of surgical performance, but in particular, it can highlight specific points of interest among anatomical structures that the surgeons dwelled on according to their level of expertise.

  7. Cognitive performance patterns in healthy individuals with substantia nigra hyperechogenicity and early Parkinson’s disease

    Directory of Open Access Journals (Sweden)

    Rezzak Yilmaz

    2016-11-01

    Full Text Available Introduction: Hyperechogenicity of the substantia nigra (SN+ is a risk marker for Parkinson’s disease (PD which can be detected before the diagnosis. In healthy individuals, SN+ has been associated with slight deficits in specific cognitive functions, suggesting cognitive impairment as a possible pre-diagnostic marker for PD. However, the pattern of cognitive deficits associated with SN+ has not yet been compared with those present in PD.Methods: Data of 262 healthy individuals with normal echogenicity (SN- and 48 healthy individuals with SN+ were compared with 82 early stage PD patients using the Consortium to Establish a Registry for Alzheimer’s disease test battery. First, the test clusters (factors were identified using a principal component analysis (PCA. Mean group performance of cognitive tests belonging to distinct factors, according to the PCA, and single subtest performances were compared using analyses of variance. Second, the number of individuals with abnormal cognitive performances (z-score <-1.0 were compared between groups. Results: Verbal memory, semantic and executive function, and praxis were identified as components of cognitive performances. The SN+ group performed significantly worse than the SN- group in tests assessing semantic and executive function, with a non-significant decrease in verbal memory. On the subtest level, individuals of the SN+ group scored significantly lower than the SN- group on the Boston Naming Test (BNT (p=0.008. In all subtests, the percentages of PD patients with values below the cut-off for abnormal performance were higher than in the SN- group. Moreover, more individuals from the SN+ group scored below the cut-off in the BNT (SN-=8.4%, SN+=20.8%, p=0.01 and TMT-B (SN-=6.9%, SN+=16.7%, p=0.02, compared to the SN- group. Conclusion: This study confirms poorer performance of healthy individuals with SN+ compared to SN- in specific cognitive domains. However, against the SN- group, the cognitive

  8. Speed and Lateral Inhibition of Stimulus Processing Contribute to Individual Differences in Stroop-Task Performance.

    Science.gov (United States)

    Naber, Marnix; Vedder, Anneke; Brown, Stephen B R E; Nieuwenhuis, Sander

    2016-01-01

    The Stroop task is a popular neuropsychological test that measures executive control. Strong Stroop interference is commonly interpreted in neuropsychology as a diagnostic marker of impairment in executive control, possibly reflecting executive dysfunction. However, popular models of the Stroop task indicate that several other aspects of color and word processing may also account for individual differences in the Stroop task, independent of executive control. Here we use new approaches to investigate the degree to which individual differences in Stroop interference correlate with the relative processing speed of word and color stimuli, and the lateral inhibition between visual stimuli. We conducted an electrophysiological and behavioral experiment to measure (1) how quickly an individual's brain processes words and colors presented in isolation (P3 latency), and (2) the strength of an individual's lateral inhibition between visual representations with a visual illusion. Both measures explained at least 40% of the variance in Stroop interference across individuals. As these measures were obtained in contexts not requiring any executive control, we conclude that the Stroop effect also measures an individual's pre-set way of processing visual features such as words and colors. This study highlights the important contributions of stimulus processing speed and lateral inhibition to individual differences in Stroop interference, and challenges the general view that the Stroop task primarily assesses executive control.

  9. Modelling temporal networks of human face-to-face contacts with public activity and individual reachability

    Science.gov (United States)

    Zhang, Yi-Qing; Cui, Jing; Zhang, Shu-Min; Zhang, Qi; Li, Xiang

    2016-02-01

    Modelling temporal networks of human face-to-face contacts is vital both for understanding the spread of airborne pathogens and word-of-mouth spreading of information. Although many efforts have been devoted to model these temporal networks, there are still two important social features, public activity and individual reachability, have been ignored in these models. Here we present a simple model that captures these two features and other typical properties of empirical face-to-face contact networks. The model describes agents which are characterized by an attractiveness to slow down the motion of nearby people, have event-triggered active probability and perform an activity-dependent biased random walk in a square box with periodic boundary. The model quantitatively reproduces two empirical temporal networks of human face-to-face contacts which are testified by their network properties and the epidemic spread dynamics on them.

  10. A monitoring tool for performance improvement in plastic surgery at the individual level.

    Science.gov (United States)

    Maruthappu, Mahiben; Duclos, Antoine; Orgill, Dennis; Carty, Matthew J

    2013-05-01

    The assessment of performance in surgery is expanding significantly. Application of relevant frameworks to plastic surgery, however, has been limited. In this article, the authors present two robust graphic tools commonly used in other industries that may serve to monitor individual surgeon operative time while factoring in patient- and surgeon-specific elements. The authors reviewed performance data from all bilateral reduction mammaplasties performed at their institution by eight surgeons between 1995 and 2010. Operative time was used as a proxy for performance. Cumulative sum charts and exponentially weighted moving average charts were generated using a train-test analytic approach, and used to monitor surgical performance. Charts mapped crude, patient case-mix-adjusted, and case-mix and surgical-experience-adjusted performance. Operative time was found to decline from 182 minutes to 118 minutes with surgical experience (p factors is essential for correct interpretation of performance in plastic surgery at the individual surgeon level. Cumulative sum and exponentially weighted moving average charts represent accurate methods of monitoring operative time to control and potentially improve surgeon performance over the course of a career.

  11. Driven by fear: the effect of success and failure information on passionate individuals' performance.

    Science.gov (United States)

    Bélanger, Jocelyn J; Lafrenière, Marc-André K; Vallerand, Robert J; Kruglanski, Arie W

    2013-01-01

    Four studies investigated the impact of success and failure information on passionate individuals' performance. Obsessive passion, characterized by a rigid and defensive mode of functioning, predicted greater performance in domains both related and unrelated to the passionate activity in response to exposure to failure information. Conversely, harmonious passion, characterized by a flexible, nondefensive mode of functioning, was found to be unaffected by success or failure information. These performance effects were deeply ingrained, did not require conscious thought, and were automatically activated after unconscious exposure to failure-related words. In addition, the present research evinced that following failure information, obsessive passion predicted increases of performance through its effect on fear of failure. However, performance augmented only when the performance task was framed in such a way that failure would entail important negative consequences for the self and not when framed as inconsequential.

  12. Constrained bayesian inference of project performance models

    OpenAIRE

    Sunmola, Funlade

    2013-01-01

    Project performance models play an important role in the management of project success. When used for monitoring projects, they can offer predictive ability such as indications of possible delivery problems. Approaches for monitoring project performance relies on available project information including restrictions imposed on the project, particularly the constraints of cost, quality, scope and time. We study in this paper a Bayesian inference methodology for project performance modelling in ...

  13. Adjudicating between face-coding models with individual-face fMRI responses.

    Directory of Open Access Journals (Sweden)

    Johan D Carlin

    2017-07-01

    Full Text Available The perceptual representation of individual faces is often explained with reference to a norm-based face space. In such spaces, individuals are encoded as vectors where identity is primarily conveyed by direction and distinctiveness by eccentricity. Here we measured human fMRI responses and psychophysical similarity judgments of individual face exemplars, which were generated as realistic 3D animations using a computer-graphics model. We developed and evaluated multiple neurobiologically plausible computational models, each of which predicts a representational distance matrix and a regional-mean activation profile for 24 face stimuli. In the fusiform face area, a face-space coding model with sigmoidal ramp tuning provided a better account of the data than one based on exemplar tuning. However, an image-processing model with weighted banks of Gabor filters performed similarly. Accounting for the data required the inclusion of a measurement-level population averaging mechanism that approximates how fMRI voxels locally average distinct neuronal tunings. Our study demonstrates the importance of comparing multiple models and of modeling the measurement process in computational neuroimaging.

  14. Transmutation Fuel Performance Code Thermal Model Verification

    Energy Technology Data Exchange (ETDEWEB)

    Gregory K. Miller; Pavel G. Medvedev

    2007-09-01

    FRAPCON fuel performance code is being modified to be able to model performance of the nuclear fuels of interest to the Global Nuclear Energy Partnership (GNEP). The present report documents the effort for verification of the FRAPCON thermal model. It was found that, with minor modifications, FRAPCON thermal model temperature calculation agrees with that of the commercial software ABAQUS (Version 6.4-4). This report outlines the methodology of the verification, code input, and calculation results.

  15. Type of High School Predicts Academic Performance at University Better than Individual Differences.

    Science.gov (United States)

    Banai, Benjamin; Perin, Višnja

    2016-01-01

    Psychological correlates of academic performance have always been of high relevance to psychological research. The relation between psychometric intelligence and academic performance is one of the most consistent and well-established findings in psychology. It is hypothesized that intelligence puts a limit on what an individual can learn or achieve. Moreover, a growing body of literature indicates a relationship between personality traits and academic performance. This relationship helps us to better understand how an individual will learn or achieve their goals. The aim of this study is to further investigate the relationship between psychological correlates of academic performance by exploring the potentially moderating role of prior education. The participants in this study differed in the type of high school they attended. They went either to gymnasium, a general education type of high school that prepares students specifically for university studies, or to vocational school, which prepares students both for the labour market and for further studies. In this study, we used archival data of psychological testing during career guidance in the final year of high school, and information about the university graduation of those who received guidance. The psychological measures included intelligence, personality and general knowledge. The results show that gymnasium students had greater chances of performing well at university, and that this relationship exceeds the contribution of intelligence and personality traits to university graduation. Moreover, psychological measures did not interact with type of high school, which indicates that students from different school types do not profit from certain individual characteristics.

  16. Model performance analysis and model validation in logistic regression

    Directory of Open Access Journals (Sweden)

    Rosa Arboretti Giancristofaro

    2007-10-01

    Full Text Available In this paper a new model validation procedure for a logistic regression model is presented. At first, we illustrate a brief review of different techniques of model validation. Next, we define a number of properties required for a model to be considered "good", and a number of quantitative performance measures. Lastly, we describe a methodology for the assessment of the performance of a given model by using an example taken from a management study.

  17. Identifying the connective strength between model parameters and performance criteria

    Directory of Open Access Journals (Sweden)

    B. Guse

    2017-11-01

    is found for low- and mid-flow conditions. Moreover, the RT analyses emphasise the benefit of an individual analysis of the three components of KGE and of the FDC segments. Furthermore, the RT analyses highlight under which conditions these performance criteria provide insights into precise parameter identification. Our results show that separate performance criteria are required to identify dominant parameters on low- and mid-flow conditions, whilst the number of required performance criteria for high flows increases with increasing process complexity in the catchment. Overall, the analysis of the connective strength between model parameters and performance criteria using RTs contribute to a more realistic handling of parameters and performance criteria in hydrological modelling.

  18. Longitudinal intra- and inter-individual variability in young swimmers' performance and determinant competition factors

    Directory of Open Access Journals (Sweden)

    Jorge Estrela Morais

    2014-09-01

    Full Text Available The main purpose of this study was to follow-up the intra- and inter-individual variability of young swimmers' performance and determinant factors over two competitive seasons. Thirty young swimmers (14 boys: 12.33±0.65 years-old; 16 girls: 11.15±0.55 years-old were followed-up throughout two consecutive seasons (seven evaluation moments. Performance (100m freestyle, anthropometric, kinematic, hydrodynamic and efficiency features were evaluated. A gender and skill-level effect was observed. Boys improved in a higher amount (% comparing to girls. Overall, swimmers in skill-level 2 (both genders presented a higher intra-individual variability. Performance and anthropometrics showed a significant inter-individual variability in most moments, but hydrodynamics, kinematics and efficiency did not. Within each skill-level hydrodynamics, kinematics and efficiency were the variables that showed a high inter-individual variability. As a gender and skill-level effect was noticed in an age-group of young swimmers, coaches and practitioners should put the focus in specific and customized training plans for each skill-level of swimmers.

  19. Teori Adult Learning, Ekspriental Learning Cycle Dan Perubahan Performance Individu Dalam Pendidikan Dan Pelatihan

    Directory of Open Access Journals (Sweden)

    Moh. Dannur

    2017-07-01

    Full Text Available Teori belajar merupakan hal yang sangat penting dalam Manajmen Pendidikan dan Pelatihan apabila ingin meraih hasil yang maksimal dalam proses transformasi pengetahuan. Adult Learning dan Ekspriental Learning Cycle salah satu teori yang paling masyhur di dalamnya. Dalam upaya meraih hasil yang maksimal juga perlu adanya pengetahuan tentang motivasi dan faktor-faktor dalam pengembangan individu, perubahan performanya, serta dinamika individu kelompok. Sehingga dengan pengetahuan yang dimilikiakan dengan mudah merealisasikan yang diinginkan. Kata kunci: Adult learning, expriental learning cycle, performance.  Learning theory is very important in Management of Education and Training if you want to achieve the maximum results in the transformation process of knowledge. Adult Learning and Expriental Learning Cycle are the most famous theories within it. In the effort to achieve the maximum results also needs the knowledge about motivation, the factors in the development of individuals, the changes of performance, and the dynamics of individual groups. So with this knowledge you will easily realize the thing you desired. Keywords: Adult learning, expriental learning cycle, performance.

  20. Can a mathematical model predict an individual's trait-like response to both total and partial sleep loss?

    Science.gov (United States)

    Ramakrishnan, Sridhar; Lu, Wei; Laxminarayan, Srinivas; Wesensten, Nancy J; Rupp, Tracy L; Balkin, Thomas J; Reifman, Jaques

    2015-06-01

    Humans display a trait-like response to sleep loss. However, it is not known whether this trait-like response can be captured by a mathematical model from only one sleep-loss condition to facilitate neurobehavioural performance prediction of the same individual during a different sleep-loss condition. In this paper, we investigated the extent to which the recently developed unified mathematical model of performance (UMP) captured such trait-like features for different sleep-loss conditions. We used the UMP to develop two sets of individual-specific models for 15 healthy adults who underwent two different sleep-loss challenges (order counterbalanced; separated by 2-4 weeks): (i) 64 h of total sleep deprivation (TSD) and (ii) chronic sleep restriction (CSR) of 7 days of 3 h nightly time in bed. We then quantified the extent to which models developed using psychomotor vigilance task data under TSD predicted performance data under CSR, and vice versa. The results showed that the models customized to an individual under one sleep-loss condition accurately predicted performance of the same individual under the other condition, yielding, on average, up to 50% improvement over non-individualized, group-average model predictions. This finding supports the notion that the UMP captures an individual's trait-like response to different sleep-loss conditions. © 2014 European Sleep Research Society.

  1. Superior sensory, motor, and cognitive performance in elderly individuals with multi-year dancing activities

    Directory of Open Access Journals (Sweden)

    Jan-Christoph Kattenstroth

    2010-07-01

    Full Text Available Aging is associated with a progressive decline of mental and physical abilities. Considering the current demographic changes in many civilizations there is an urgent need for measures permitting an independent lifestyle into old age. The critical role of physical exercise in mediating and maintaining physical and mental fitness is well-acknowledged. Dance, in addition to physical activity, combines emotions, social interaction, sensory stimulation, motor coordination and music, thereby creating enriched environmental conditions for human individuals. Here we demonstrate the impact of multi-year (average 16.5 years amateur dancing (AD in a group of elderly subjects (aged 65 to 84 years as compared to education-, gender- and aged-matched controls (CG having no record of dancing or sporting activities. Besides posture and balance parameters, we tested reaction times, motor behavior, tactile and cognitive performance. In each of the different domains investigated, the AD group had a superior performance as compared to the non-dancer CG group. Analysis of individual performance revealed that the best participants of the AD group were not better than individuals of the CG group. Instead, the AD group lacked individuals showing poor performance, which was frequently observed for the CG group. This observation implies that maintaining a regular schedule of dancing into old age can preserve cognitive, motor and perceptual abilities and prevent them from degradation. We conclude that the far-reaching beneficial effects found in the AD group make dance, beyond its ability to facilitate balance and posture, a prime candidate for the preservation of everyday life competence of elderly individuals.

  2. Building Information Modeling (BIM) for Indoor Environmental Performance Analysis

    DEFF Research Database (Denmark)

    The report is a part of a research assignment carried out by students in the 5ETCS course “Project Byggeri – [entitled as: Building Information Modeling (BIM) – Modeling & Analysis]”, during the 3rd semester of master degree in Civil and Architectural Engineering, Department of Engineering, Aarhus...... University. This includes seven papers describing BIM for Sustainability, concentrating specifically on individual topics regarding to Indoor Environment Performance Analysis....

  3. Photovoltaic performance models - A report card

    Science.gov (United States)

    Smith, J. H.; Reiter, L. R.

    1985-01-01

    Models for the analysis of photovoltaic (PV) systems' designs, implementation policies, and economic performance, have proliferated while keeping pace with rapid changes in basic PV technology and extensive empirical data compiled for such systems' performance. Attention is presently given to the results of a comparative assessment of ten well documented and widely used models, which range in complexity from first-order approximations of PV system performance to in-depth, circuit-level characterizations. The comparisons were made on the basis of the performance of their subsystem, as well as system, elements. The models fall into three categories in light of their degree of aggregation into subsystems: (1) simplified models for first-order calculation of system performance, with easily met input requirements but limited capability to address more than a small variety of design considerations; (2) models simulating PV systems in greater detail, encompassing types primarily intended for either concentrator-incorporating or flat plate collector PV systems; and (3) models not specifically designed for PV system performance modeling, but applicable to aspects of electrical system design. Models ignoring subsystem failure or degradation are noted to exclude operating and maintenance characteristics as well.

  4. Considerations in representing human individuals in social ecological models

    Science.gov (United States)

    Manfredo, Michael J.; Teel, Tara L.; Gavin, Michael C.; Fulton, David C.

    2017-01-01

    In this chapter we focus on how to integrate the human individual into social-ecological systems analysis, and how to improve research on individual thought and action regarding the environment by locating it within the broader social-ecological context. We discuss three key questions as considerations for future research: (1) is human thought conceptualized as a dynamic and adaptive process, (2) is the individual placed in a multi-level context (including within-person levels, person-group interactions, and institutional and structural factors), and (3) is human thought seen as mutually constructed with the social and natural environment. Increased emphasis on the individual will be essential if we are to understand agency, innovation, and adaptation in social-ecological systems.

  5. A Source Activation Account of Individual Differences in Working Memory Performance

    National Research Council Canada - National Science Library

    Reder, Lynne

    1999-01-01

    ...' patterns of performance. We propose a computational model that accounts for differences in working memory capacity in terms of a quantity called source activation, which is used to maintain goal relevant information in an available state...

  6. THE WORLD-MODELLING POTENCY OF THE INDIVIDUAL METAPHOR

    Directory of Open Access Journals (Sweden)

    Pavlova, M.S.

    2016-03-01

    Full Text Available This article analyzes individual metaphors as a fundamental component of the artistic worldview. The research discusses the correlation between the individual metaphor and interdiscourse markedness that allows identifying some peculiarities of cultural identity of the English-language literary text. The central place belongs to the propositions connected with the ways of reality conceptualization in the minds of the English-speaking mentality, which are necessary for correct interpretation of the cultural-specific information.

  7. Application of individually performed titanium mesh in infraorbital wall fracture reconstruction

    Directory of Open Access Journals (Sweden)

    Kai-Jian Sun

    2016-04-01

    Full Text Available AIM:To discuss the application effect of individually performed titanium mesh in infraorbital wall fracture reconstruction. METHODS:Sixty-seven patients(67 eyesdiagnosed as infraorbital fracture from January 2011 to February 2014 were performed reconstruction with individually performed titanium mesh. The recovery of incision, visual acuity, eyeball mobility, diplopia and proptosis were monitored by post-operation follow-up which lasted for 1a. RESULTS:No infection, titanium mesh transposition, prolapse, deformities, exclusion or ectropion were occurred in the follow-up period. The eyeball embole was less than 2mm by bilateral proptosis contrast. The diplopia in 5 eyes were disappeared in 4 and approved in one. The eyeball descent in 2 cases was disappeared. The visual acuity was the same compared with pre-operation. The rate of disappeared diplopia at primary position was 93% and improved significantly in the other 3 patients. The rate of disappeared diplopia at peripheral visual field was 86% and improved significantly in the other 2 patients.CONCLUSION:The reconstruction effect of individually performed titanium mesh in infraorbital wall fracture was satisfied and safe.

  8. The Ecology of Exercise: Mechanisms Underlying Individual Variation in Behavior, Activity, and Performance: An Introduction to Symposium.

    Science.gov (United States)

    Killen, Shaun S; Calsbeek, Ryan; Williams, Tony D

    2017-08-01

    Wild animals often engage in intense physical activity while performing tasks vital for their survival and reproduction associated with foraging, avoiding predators, fighting, providing parental care, and migrating. In this theme issue we consider how viewing these tasks as "exercise"-analogous to that performed by human athletes-may help provide insight into the mechanisms underlying individual variation in these types of behaviors and the importance of physical activity in an ecological context. In this article and throughout this issue, we focus on four key questions relevant to the study of behavioral ecology that may be addressed by studying wild animal behavior from the perspective of exercise physiology: (1) How hard do individual animals work in response to ecological (or evolutionary) demands?; (2) Do lab-based studies of activity provide good models for understanding activity in free-living animals and individual variation in traits?; (3) Can animals work too hard during "routine" activities?; and (4) Can paradigms of "exercise" and "training" be applied to free-living animals? Attempts to address these issues are currently being facilitated by rapid technological developments associated with physiological measurements and the remote tracking of wild animals, to provide mechanistic insights into the behavior of free-ranging animals at spatial and temporal scales that were previously impossible. We further suggest that viewing the behaviors of non-human animals in terms of the physical exercise performed will allow us to fully take advantage of these technological advances, draw from knowledge and conceptual frameworks already in use by human exercise physiologists, and identify key traits that constrain performance and generate variation in performance among individuals. It is our hope that, by highlighting mechanisms of behavior and performance, the articles in this issue will spur on further synergies between physiologists and ecologists, to take

  9. 42 CFR Appendix to Part 54a - Model Notice of Individuals Receiving Substance Abuse Services

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Model Notice of Individuals Receiving Substance... ORGANIZATIONS RECEIVING DISCRETIONARY FUNDING UNDER TITLE V OF THE PUBLIC HEALTH SERVICE ACT, 42 U.S.C. 290aa...—Model Notice of Individuals Receiving Substance Abuse Services Model Notice to Individuals Receiving...

  10. Automated MRI segmentation for individualized modeling of current flow in the human head.

    Science.gov (United States)

    Huang, Yu; Dmochowski, Jacek P; Su, Yuzhuo; Datta, Abhishek; Rorden, Christopher; Parra, Lucas C

    2013-12-01

    High-definition transcranial direct current stimulation (HD-tDCS) and high-density electroencephalography require accurate models of current flow for precise targeting and current source reconstruction. At a minimum, such modeling must capture the idiosyncratic anatomy of the brain, cerebrospinal fluid (CSF) and skull for each individual subject. Currently, the process to build such high-resolution individualized models from structural magnetic resonance images requires labor-intensive manual segmentation, even when utilizing available automated segmentation tools. Also, accurate placement of many high-density electrodes on an individual scalp is a tedious procedure. The goal was to develop fully automated techniques to reduce the manual effort in such a modeling process. A fully automated segmentation technique based on Statical Parametric Mapping 8, including an improved tissue probability map and an automated correction routine for segmentation errors, was developed, along with an automated electrode placement tool for high-density arrays. The performance of these automated routines was evaluated against results from manual segmentation on four healthy subjects and seven stroke patients. The criteria include segmentation accuracy, the difference of current flow distributions in resulting HD-tDCS models and the optimized current flow intensities on cortical targets. The segmentation tool can segment out not just the brain but also provide accurate results for CSF, skull and other soft tissues with a field of view extending to the neck. Compared to manual results, automated segmentation deviates by only 7% and 18% for normal and stroke subjects, respectively. The predicted electric fields in the brain deviate by 12% and 29% respectively, which is well within the variability observed for various modeling choices. Finally, optimized current flow intensities on cortical targets do not differ significantly. Fully automated individualized modeling may now be feasible

  11. Impact of aging on neurocognitive performance in previously antiretroviral-naive HIV-infected individuals on their first suppressive regimen.

    Science.gov (United States)

    Coban, Hamza; Robertson, Kevin; Smurzynski, Marlene; Krishnan, Supriya; Wu, Kunling; Bosch, Ronald J; Collier, Ann C; Ellis, Ronald J

    2017-07-17

    Despite treatment with virologically suppressive antiretroviral therapy (ART), neurocognitive impairment may persist or develop de novo in aging HIV-infected individuals. We evaluated advancing age as a predictor of neurocognitive impairment in a large cohort of previously ART-naive individuals on long-term ART. The AIDS Clinical Trials Group Longitudinal Linked Randomized Trials was a prospective cohort study of HIV-infected individuals originally enrolled in randomized ART trials. This analysis examined neurocognitive outcomes at least 2 years after ART initiation. All participants underwent annual neurocognitive testing consisting of Trail making A and B, the wechsler adult intelligence scale-revised Digit Symbol and Hopkins Verbal Learning Tests. Uni and multivariable repeated measures regression models evaluated factors associated with neurocognitive performance. Predictors at parent study entry (ART naive) included entry demographics, smoking, injection drug use, hepatitis B surface antigen, hepatitis C virus serostatus, history of stroke, ART regimen type, pre-ART nadir CD4 cell count, and plasma viral load and as well as time-updated plasma viral load and CD4 cell count. The cohort comprised 3313 individuals with median pre-ART age of 38 years, 20% women; 36% Black, non-Hispanic; 22% Hispanic. Virologic suppression was maintained at 91% of follow-up visits. Neurocognitive performance improved with years of ART. After adjusting for the expected effects of age using norms from HIV-negative individuals, the odds of neurocognitive impairment at follow-up visits among the HIV infected increased by nearly 20% for each decade of advancing age. Despite continued virologic suppression and neurocognitive improvement in the cohort as a whole, older individuals were more likely to have neurocognitive impairment than younger individuals.

  12. Anteseden Dan Konsekuensi Kinerja Individual : Analisis Terhadap Model Keinginan Berpindah (Studi Empiris Pada Akuntan Publik Di Indonesia)

    OpenAIRE

    Raza, Hendra

    2016-01-01

    This study aims to examine empirically the antecedents of individual performance on its consequences of turnover intention in public accounting firms. There are eight variables measured which consists of auditors’ empowerment, innovation, professionalism, role ambiguity, role conflict, organizational commitment, individual performance and turnover intention. Data analysis is based on 163 public accountant using the Structural Equation Modeling assisted with an application of the Analysis Mome...

  13. A mechanistic spatio-temporal framework for modelling individual-to-individual transmission-With an application to the 2014-2015 West Africa Ebola outbreak.

    Directory of Open Access Journals (Sweden)

    Max S Y Lau

    2017-10-01

    Full Text Available In recent years there has been growing availability of individual-level spatio-temporal disease data, particularly due to the use of modern communicating devices with GPS tracking functionality. These detailed data have been proven useful for inferring disease transmission to a more refined level than previously. However, there remains a lack of statistically sound frameworks to model the underlying transmission dynamic in a mechanistic manner. Such a development is particularly crucial for enabling a general epidemic predictive framework at the individual level. In this paper we propose a new statistical framework for mechanistically modelling individual-to-individual disease transmission in a landscape with heterogeneous population density. Our methodology is first tested using simulated datasets, validating our inferential machinery. The methodology is subsequently applied to data that describes a regional Ebola outbreak in Western Africa (2014-2015. Our results show that the methods are able to obtain estimates of key epidemiological parameters that are broadly consistent with the literature, while revealing a significantly shorter distance of transmission. More importantly, in contrast to existing approaches, we are able to perform a more general model prediction that takes into account the susceptible population. Finally, our results show that, given reasonable scenarios, the framework can be an effective surrogate for susceptible-explicit individual models which are often computationally challenging.

  14. A mechanistic spatio-temporal framework for modelling individual-to-individual transmission—With an application to the 2014-2015 West Africa Ebola outbreak

    Science.gov (United States)

    McClelland, Amanda; Zelner, Jon; Streftaris, George; Funk, Sebastian; Metcalf, Jessica; Dalziel, Benjamin D.; Grenfell, Bryan T.

    2017-01-01

    In recent years there has been growing availability of individual-level spatio-temporal disease data, particularly due to the use of modern communicating devices with GPS tracking functionality. These detailed data have been proven useful for inferring disease transmission to a more refined level than previously. However, there remains a lack of statistically sound frameworks to model the underlying transmission dynamic in a mechanistic manner. Such a development is particularly crucial for enabling a general epidemic predictive framework at the individual level. In this paper we propose a new statistical framework for mechanistically modelling individual-to-individual disease transmission in a landscape with heterogeneous population density. Our methodology is first tested using simulated datasets, validating our inferential machinery. The methodology is subsequently applied to data that describes a regional Ebola outbreak in Western Africa (2014-2015). Our results show that the methods are able to obtain estimates of key epidemiological parameters that are broadly consistent with the literature, while revealing a significantly shorter distance of transmission. More importantly, in contrast to existing approaches, we are able to perform a more general model prediction that takes into account the susceptible population. Finally, our results show that, given reasonable scenarios, the framework can be an effective surrogate for susceptible-explicit individual models which are often computationally challenging. PMID:29084216

  15. An Integrated, Multifactorial Approach to Periodization for Optimal Performance in Individual and Team Sports.

    Science.gov (United States)

    Mujika, Iñigo; Halson, Shona; Burke, Louise M; Balagué, Gloria; Farrow, Damian

    2018-05-01

    Sports periodization has traditionally focused on the exercise aspect of athletic preparation, while neglecting the integration of other elements that can impact an athlete's readiness for peak competition performances. Integrated periodization allows the coordinated inclusion of multiple training components best suited for a given training phase into an athlete's program. The aim of this article is to review the available evidence underpinning integrated periodization, focusing on exercise training, recovery, nutrition, psychological skills, and skill acquisition as key factors by which athletic preparation can be periodized. The periodization of heat and altitude adaptation, body composition, and physical therapy is also considered. Despite recent criticism, various methods of exercise training periodization can contribute to performance enhancement in a variety of elite individual and team sports, such as soccer. In the latter, both physical and strategic periodization are useful tools for managing the heavy travel schedule, fatigue, and injuries that occur throughout a competitive season. Recovery interventions should be periodized (ie, withheld or emphasized) to influence acute and chronic training adaptation and performance. Nutrient intake and timing in relation to exercise and as part of the periodization of an athlete's training and competition calendar can also promote physiological adaptations and performance capacity. Psychological skills are a central component of athletic performance, and their periodization should cater to each athlete's individual needs and the needs of the team. Skill acquisition can also be integrated into an athlete's periodized training program to make a significant contribution to competition performance.

  16. Individualized prediction of perineural invasion in colorectal cancer: development and validation of a radiomics prediction model.

    Science.gov (United States)

    Huang, Yanqi; He, Lan; Dong, Di; Yang, Caiyun; Liang, Cuishan; Chen, Xin; Ma, Zelan; Huang, Xiaomei; Yao, Su; Liang, Changhong; Tian, Jie; Liu, Zaiyi

    2018-02-01

    To develop and validate a radiomics prediction model for individualized prediction of perineural invasion (PNI) in colorectal cancer (CRC). After computed tomography (CT) radiomics features extraction, a radiomics signature was constructed in derivation cohort (346 CRC patients). A prediction model was developed to integrate the radiomics signature and clinical candidate predictors [age, sex, tumor location, and carcinoembryonic antigen (CEA) level]. Apparent prediction performance was assessed. After internal validation, independent temporal validation (separate from the cohort used to build the model) was then conducted in 217 CRC patients. The final model was converted to an easy-to-use nomogram. The developed radiomics nomogram that integrated the radiomics signature and CEA level showed good calibration and discrimination performance [Harrell's concordance index (c-index): 0.817; 95% confidence interval (95% CI): 0.811-0.823]. Application of the nomogram in validation cohort gave a comparable calibration and discrimination (c-index: 0.803; 95% CI: 0.794-0.812). Integrating the radiomics signature and CEA level into a radiomics prediction model enables easy and effective risk assessment of PNI in CRC. This stratification of patients according to their PNI status may provide a basis for individualized auxiliary treatment.

  17. The Comparison of Mental Rotation Performance in Team and Individual Sports of Students

    Directory of Open Access Journals (Sweden)

    Fatemeh Pasand

    2015-01-01

    Full Text Available As a practical and causal-comparative study, the present study was aimed at comparing the mental rotation performance in team and individual sports among students. The statistical population included all of the female and male athletes (N=1500 from different districts of Shiraz, Iran who participated in the sport clubs. The participants of this study included 240 students between 12-14 years old (120 girls and 120 boys who were selected randomly from four sport fields (Volleyball, Basketball, Karate, and Gymnastics. Finally, 30 athletes were selected from each field. The Mentrat Program, a kind of software for the Mental Rotation Test was used as an evaluation tool. Analyses of variance (ANOVA with repeated measures were conducted to analysis of data. The results indicated that the impact of the rotational angle was significant in both team and individual groups (p0.05. It was also observed that there was a significant difference between the mental rotation scores of the males in the individual groups contrary to the ones in the team groups (p<0.05. As a whole, it seems that as the rotational angle increases, the ability of the mental rotation in the individual fields of sport (males will be higher compared to the team groups. Keywords: Mental Rotation, Rotational Angle, Team and Individual Sports, Students

  18. External supports improve knee performance in anterior cruciate ligament reconstructed individuals with higher kinesiophobia levels.

    Science.gov (United States)

    Harput, Gulcan; Ulusoy, Burak; Ozer, Hamza; Baltaci, Gul; Richards, Jim

    2016-10-01

    The objectives of this study were to investigate the effects of knee brace (KB) and kinesiotaping (KT) on functional performance and self-reported function in individuals six months post-ACLR who desired to return to their pre-injury activity levels but felt unable to do so due to kinesiophobia. This was a cross-sectional study involving 30 individuals six months post-ACLR with Tampa Kinesiophobia Scores >37. Individuals were tested under three conditions: no intervention, KB and KT in a randomized order. Isokinetic concentric quadriceps and hamstring strength tests, one leg hop test, star excursion balance test and global rating scale were assessed under the three conditions. The involved side showed that KT and KB significantly increased the hop distance (P=0.01, P=0.04) and improved balance (P=0.01, P=0.04), respectively, but only KB was found to increase the quadriceps and hamstring peak torques compared to no intervention (P<0.05). Individuals reported having better knee function with KB when compared to no intervention (P<0.001) and KT (P=0.03). Both KB and KT have positive effects in individuals post-ACLR which may assist in reducing kinesiophobia when returning to their pre-injury activity levels, with the KB appearing to offer the participants better knee function compared to KT. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. [Influence of Nurses' Self-leadership on Individual and Team Members' Work Role Performance].

    Science.gov (United States)

    Kim, Se Young; Kim, Eun Kyung; Kim, Byungsoo; Lee, Eunpyo

    2016-06-01

    The purpose of this study was to examine correlations between nurses' self-leadership and individual work role performance and correlations between self-leadership in nursing units and team members' work role performance. Participants were 202 conveniently selected general nurses from 5 general hospitals in Korea. The study was carried out on 35 nursing units. Data were collected during February 2015 with self-report questionnaires. For factors affecting individual work role performance, self-expectation, self-goal setting, constructive thought, clinical career in the present nursing unit and marital status accounted for 44.0% of proficiency, while self-expectation, self-goal setting, constructive thought, and marital status accounted for 42.3% of adaptivity. Self-expectation, self-goal setting, constructive thought, self-reward, clinical career in the present nursing unit and position accounted for 26.4% of proactivity. In terms of team members' work role performance, self-reward and self-expectation in nursing units explained 29.0% of team members' proficiency. Self-reward and self-expectation in nursing units explained 31.6% of team members' adaptivity, and self-reward in nursing units explained 16.8% of team members' proactivity. The results confirm that nurses' self-leadership affects not only individual self-leadership but also team members' work role performance. Accordingly, to improve nurses' work role performance in nursing units of nursing organizations, improvement in nursing environment based on self-leadership education is necessary and nurses' tasks rearranged so they can appreciate work-autonomy and challenges of work.

  20. Iowa calibration of MEPDG performance prediction models.

    Science.gov (United States)

    2013-06-01

    This study aims to improve the accuracy of AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG) pavement : performance predictions for Iowa pavement systems through local calibration of MEPDG prediction models. A total of 130 : representative p...

  1. Cortical Brain Atrophy and Intra-Individual Variability in Neuropsychological Test Performance in HIV Disease

    Science.gov (United States)

    HINES, Lindsay J.; MILLER, Eric N.; HINKIN, Charles H.; ALGER, Jeffery R.; BARKER, Peter; GOODKIN, Karl; MARTIN, Eileen M.; MARUCA, Victoria; RAGIN, Ann; SACKTOR, Ned; SANDERS, Joanne; SELNES, Ola; BECKER, James T.

    2015-01-01

    Objective To characterize the relationship between dispersion-based intra-individual variability (IIVd) in neuropsychological test performance and brain volume among HIV seropositive and seronegative men and to determine the effects of cardiovascular risk and HIV infection on this relationship. Methods Magnetic Resonance Imaging (MRI) was used to acquire high-resolution neuroanatomic data from 147 men age 50 and over, including 80 HIV seropositive (HIV+) and 67 seronegative controls (HIV−) in this cross-sectional cohort study. Voxel Based Morphometry was used to derive volumetric measurements at the level of the individual voxel. These brain structure maps were analyzed using Statistical Parametric Mapping (SPM2). IIVd was measured by computing intra-individual standard deviations (ISD’s) from the standardized performance scores of five neuropsychological tests: Wechsler Memory Scale-III Visual Reproduction I and II, Logical Memory I and II, Wechsler Adult Intelligence Scale-III Letter Number Sequencing. Results Total gray matter (GM) volume was inversely associated with IIVd. Among all subjects, IIVd -related GM atrophy was observed primarily in: 1) the inferior frontal gyrus bilaterally, the left inferior temporal gyrus extending to the supramarginal gyrus, spanning the lateral sulcus; 2) the right superior parietal lobule and intraparietal sulcus; and, 3) dorsal/ventral regions of the posterior section of the transverse temporal gyrus. HIV status, biological, and cardiovascular disease (CVD) variables were not linked to IIVd -related GM atrophy. Conclusions IIVd in neuropsychological test performance may be a sensitive marker of cortical integrity in older adults, regardless of HIV infection status or CVD risk factors, and degree of intra-individual variability links with volume loss in specific cortical regions; independent of mean-level performance on neuropsychological tests. PMID:26303224

  2. The Relationship of Some Personality and Individual Characteristics with an Individual's Commitment to an Ideal Vision for Performance Improvement.

    Science.gov (United States)

    Watkins, Ryan

    2001-01-01

    Examined the relationship among specified personality and individual characteristics of university students with their level of commitment to a measurable, results-focused statement of an ideal vision. Discusses locus of control, generativity, self-efficacy, values, and risk taking in the use of an ideal vision for strategic planning, needs…

  3. Touch Screen Performance by Individuals With and Without Motor Control Disabilities

    Science.gov (United States)

    Chen, Karen B.; Savage, Anne B.; Chourasia, Amrish O.; Wiegmann, Douglas A.; Sesto, Mary E.

    2012-01-01

    Touch technology is becoming more prevalent as functionality improves and cost decreases. Therefore, it is important that this technology is accessible to users with diverse abilities. The objective of this study was to investigate the effects of button and gap size on performance by individuals with varied motor abilities. Participants with (n=38) and without (n=15) a motor control disability completed a digit entry task. Button size ranged from 10 to 30 mm and gap size was either 1 or 3 mm. Results indicated that as button size increased, there was a decrease in misses, errors, and time to complete tasks. Performance for the non-disabled group plateaued at button size 20mm, with minimal, if any gains observed with larger button sizes. In comparison, the disabled group’s performance continued to improve as button size increased. Gap size did not affect user performance. These results may help to improve accessibility of touch technology. PMID:23021630

  4. Portraying the Contribution of Individual Behaviors to Team Cohesion and Performance

    Science.gov (United States)

    Parke, Bonny; Orasanu, Judith

    2012-01-01

    Behaviors of individuals in teams both contribute to and are molded by team dynamics. How they do so has been the subject of much research. A method of portraying individuals' behaviors in teams, the Team Diagramming Method (TDM) is presented. Behaviors are rated by other team members on three important dimensions: positivity/negativity, dominant/submissive, and task-orientedness/expressiveness. A study of 5-person teams engaging in a 3-day moon simulation task demonstrated that measures of these perceived behaviors as well as the variances of these behaviors correlated with cohesion measures and performance. The method shows strengths and weaknesses of particular teams and, by comparison with high-performing teams, suggests interventions based on individual as well as team behaviors. The primary goal of this study was to determine the extent to which these team level variables, derived from all team members' rated behaviors, were associated with previous methods of measuring cohesion and with performance. A secondary goal was to determine the stability of TDM measures over time by comparing team level variables based on ratings early and later in the team s work together.

  5. Effects of Sleep Deprivation on Brain Bioenergetics, Sleep, and Cognitive Performance in Cocaine-Dependent Individuals

    Science.gov (United States)

    Trksak, George H.; Bracken, Bethany K.; Jensen, J. Eric; Plante, David T.; Penetar, David M.; Tartarini, Wendy L.; Maywalt, Melissa A.; Dorsey, Cynthia M.; Renshaw, Perry F.; Lukas, Scott E.

    2013-01-01

    In cocaine-dependent individuals, sleep is disturbed during cocaine use and abstinence, highlighting the importance of examining the behavioral and homeostatic response to acute sleep loss in these individuals. The current study was designed to identify a differential effect of sleep deprivation on brain bioenergetics, cognitive performance, and sleep between cocaine-dependent and healthy control participants. 14 healthy control and 8 cocaine-dependent participants experienced consecutive nights of baseline, total sleep deprivation, and recovery sleep in the research laboratory. Participants underwent [31]P magnetic resonance spectroscopy (MRS) brain imaging, polysomnography, Continuous Performance Task, and Digit Symbol Substitution Task. Following recovery sleep, [31]P MRS scans revealed that cocaine-dependent participants exhibited elevated global brain β-NTP (direct measure of adenosine triphosphate), α-NTP, and total NTP levels compared to those of healthy controls. Cocaine-dependent participants performed worse on the Continuous Performance Task and Digit Symbol Substitution Task at baseline compared to healthy control participants, but sleep deprivation did not worsen cognitive performance in either group. Enhancements of brain ATP levels in cocaine dependent participants following recovery sleep may reflect a greater impact of sleep deprivation on sleep homeostasis, which may highlight the importance of monitoring sleep during abstinence and the potential influence of sleep loss in drug relapse. PMID:24250276

  6. Team Performance and Error Management in Chinese and American Simulated Flight Crews: The Role of Cultural and Individual Differences

    Science.gov (United States)

    Davis, Donald D.; Bryant, Janet L.; Tedrow, Lara; Liu, Ying; Selgrade, Katherine A.; Downey, Heather J.

    2005-01-01

    This report describes results of a study conducted for NASA-Langley Research Center. This study is part of a program of research conducted for NASA-LARC that has focused on identifying the influence of national culture on the performance of flight crews. We first reviewed the literature devoted to models of teamwork and team performance, crew resource management, error management, and cross-cultural psychology. Davis (1999) reported the results of this review and presented a model that depicted how national culture could influence teamwork and performance in flight crews. The second study in this research program examined accident investigations of foreign airlines in the United States conducted by the National Transportation Safety Board (NTSB). The ability of cross-cultural values to explain national differences in flight outcomes was examined. Cultural values were found to covary in a predicted way with national differences, but the absence of necessary data in the NTSB reports and limitations in the research method that was used prevented a clear understanding of the causal impact of cultural values. Moreover, individual differences such as personality traits were not examined in this study. Davis and Kuang (2001) report results of this second study. The research summarized in the current report extends this previous research by directly assessing cultural and individual differences among students from the United States and China who were trained to fly in a flight simulator using desktop computer workstations. The research design used in this study allowed delineation of the impact of national origin, cultural values, personality traits, cognitive style, shared mental model, and task workload on teamwork, error management and flight outcomes. We briefly review the literature that documents the importance of teamwork and error management and its impact on flight crew performance. We next examine teamwork and crew resource management training designed to improve

  7. A method to assess the influence of individual player performance distribution on match outcome in team sports.

    Science.gov (United States)

    Robertson, Sam; Gupta, Ritu; McIntosh, Sam

    2016-10-01

    This study developed a method to determine whether the distribution of individual player performances can be modelled to explain match outcome in team sports, using Australian Rules football as an example. Player-recorded values (converted to a percentage of team total) in 11 commonly reported performance indicators were obtained for all regular season matches played during the 2014 Australian Football League season, with team totals also recorded. Multiple features relating to heuristically determined percentiles for each performance indicator were then extracted for each team and match, along with the outcome (win/loss). A generalised estimating equation model comprising eight key features was developed, explaining match outcome at a median accuracy of 63.9% under 10-fold cross-validation. Lower 75th, 90th and 95th percentile values for team goals and higher 25th and 50th percentile values for disposals were linked with winning. Lower 95th and higher 25th percentile values for Inside 50s and Marks, respectively, were also important contributors. These results provide evidence supporting team strategies which aim to obtain an even spread of goal scorers in Australian Rules football. The method developed in this investigation could be used to quantify the importance of individual contributions to overall team performance in team sports.

  8. Callosotomy affects performance IQ: A meta-analysis of individual participant data.

    Science.gov (United States)

    Westerhausen, René; Karud, Celine M R

    2018-02-05

    Morphometric neuroimaging studies on healthy adult individuals regularly report a positive association between intelligence test performance (IQ) and structural properties of the corpus callosum (CC). At the same time, studies examining the effect of callosotomy on epilepsy patients report only negligible changes in IQ as result of the surgery, partially contradicting the findings of the morphometry studies. Objective of the present meta-analysis of individual participant data (IPD) of 87 cases from 16 reports was to re-investigate the effect of callosotomy on full scale IQ as well as on the verbal and performance subscale under special consideration of two possible moderating factors: pre-surgical IQ levels and the extent of the surgery (complete vs. anterior transsection). The main finding was that callosotomy selectively affects performance IQ, whereby the effect is modulated by the pre-surgical level of performance. Patients with an above-median pre-surgery performance IQ level show a significant average decrease of -5.44 (CI 95% : - 8.33 to - 2.56) IQ points following the surgery, while the below-median group does not reveal a significant change in IQ (mean change: 1.01 IQ points; CI 95% : -1.83 to 3.86). Thus, the present analyses support the notion that callosotomy has a negative effect on the patients' performance IQ, but only in those patients, who at least have an average performance levels before the surgery. This observation also lends support to the findings of previous morphometry studies, indicating that the frequently observed CC-IQ correlation might indeed reflect a functional contribution of callosal interhemispheric connectivity to intelligence-test performance. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  9. Cost and Performance Model for Photovoltaic Systems

    Science.gov (United States)

    Borden, C. S.; Smith, J. H.; Davisson, M. C.; Reiter, L. J.

    1986-01-01

    Lifetime cost and performance (LCP) model assists in assessment of design options for photovoltaic systems. LCP is simulation of performance, cost, and revenue streams associated with photovoltaic power systems connected to electric-utility grid. LCP provides user with substantial flexibility in specifying technical and economic environment of application.

  10. Hybrid Modelling of Individual Movement and Collective Behaviour

    KAUST Repository

    Franz, Benjamin; Erban, Radek

    2013-01-01

    Mathematical models of dispersal in biological systems are often written in terms of partial differential equations (PDEs) which describe the time evolution of population-level variables (concentrations, densities). A more detailed modelling

  11. Assessing Ecosystem Model Performance in Semiarid Systems

    Science.gov (United States)

    Thomas, A.; Dietze, M.; Scott, R. L.; Biederman, J. A.

    2017-12-01

    In ecosystem process modelling, comparing outputs to benchmark datasets observed in the field is an important way to validate models, allowing the modelling community to track model performance over time and compare models at specific sites. Multi-model comparison projects as well as models themselves have largely been focused on temperate forests and similar biomes. Semiarid regions, on the other hand, are underrepresented in land surface and ecosystem modelling efforts, and yet will be disproportionately impacted by disturbances such as climate change due to their sensitivity to changes in the water balance. Benchmarking models at semiarid sites is an important step in assessing and improving models' suitability for predicting the impact of disturbance on semiarid ecosystems. In this study, several ecosystem models were compared at a semiarid grassland in southwestern Arizona using PEcAn, or the Predictive Ecosystem Analyzer, an open-source eco-informatics toolbox ideal for creating the repeatable model workflows necessary for benchmarking. Models included SIPNET, DALEC, JULES, ED2, GDAY, LPJ-GUESS, MAESPA, CLM, CABLE, and FATES. Comparison between model output and benchmarks such as net ecosystem exchange (NEE) tended to produce high root mean square error and low correlation coefficients, reflecting poor simulation of seasonality and the tendency for models to create much higher carbon sources than observed. These results indicate that ecosystem models do not currently adequately represent semiarid ecosystem processes.

  12. My IEP: A Student-Directed Individualized Education Program Model

    Science.gov (United States)

    Royer, David J.

    2017-01-01

    Students with disabilities need to be more involved in planning and presenting individualized education program (IEP) meetings, and teachers need an effective, efficient curriculum to teach students how. "My IEP" curriculum uses folding graphic organizers to teach students to self-direct IEP meetings, targeting self-advocacy and…

  13. Therapeutic Enactment: Integrating Individual and Group Counseling Models for Change

    Science.gov (United States)

    Westwood, Marvin J.; Keats, Patrice A.; Wilensky, Patricia

    2003-01-01

    The purpose of this article is to introduce the reader to a group-based therapy model known as therapeutic enactment. A description of this multimodal change model is provided by outlining the relevant background information, key concepts related to specific change processes, and the differences in this model compared to earlier psychodrama…

  14. Building aggregate timber supply models from individual harvest choice

    Science.gov (United States)

    Maksym Polyakov; David N. Wear; Robert Huggett

    2009-01-01

    Timber supply has traditionally been modelled using aggregate data. In this paper, we build aggregate supply models for four roundwood products for the US state of North Carolina from a stand-level harvest choice model applied to detailed forest inventory. The simulated elasticities of pulpwood supply are much lower than reported by previous studies. Cross price...

  15. Driver Performance Model: 1. Conceptual Framework

    National Research Council Canada - National Science Library

    Heimerl, Joseph

    2001-01-01

    ...'. At the present time, no such comprehensive model exists. This report discusses a conceptual framework designed to encompass the relationships, conditions, and constraints related to direct, indirect, and remote modes of driving and thus provides a guide or 'road map' for the construction and creation of a comprehensive driver performance model.

  16. Performance engineering in the community atmosphere model

    International Nuclear Information System (INIS)

    Worley, P; Mirin, A; Drake, J; Sawyer, W

    2006-01-01

    The Community Atmosphere Model (CAM) is the atmospheric component of the Community Climate System Model (CCSM) and is the primary consumer of computer resources in typical CCSM simulations. Performance engineering has been an important aspect of CAM development throughout its existence. This paper briefly summarizes these efforts and their impacts over the past five years

  17. Performance of hedging strategies in interval models

    NARCIS (Netherlands)

    Roorda, Berend; Engwerda, Jacob; Schumacher, J.M.

    2005-01-01

    For a proper assessment of risks associated with the trading of derivatives, the performance of hedging strategies should be evaluated not only in the context of the idealized model that has served as the basis of strategy development, but also in the context of other models. In this paper we

  18. Innovations in individual feature history management - The significance of feature-based temporal model

    Science.gov (United States)

    Choi, J.; Seong, J.C.; Kim, B.; Usery, E.L.

    2008-01-01

    A feature relies on three dimensions (space, theme, and time) for its representation. Even though spatiotemporal models have been proposed, they have principally focused on the spatial changes of a feature. In this paper, a feature-based temporal model is proposed to represent the changes of both space and theme independently. The proposed model modifies the ISO's temporal schema and adds new explicit temporal relationship structure that stores temporal topological relationship with the ISO's temporal primitives of a feature in order to keep track feature history. The explicit temporal relationship can enhance query performance on feature history by removing topological comparison during query process. Further, a prototype system has been developed to test a proposed feature-based temporal model by querying land parcel history in Athens, Georgia. The result of temporal query on individual feature history shows the efficiency of the explicit temporal relationship structure. ?? Springer Science+Business Media, LLC 2007.

  19. An individual-based model for biofilm formation at liquid surfaces.

    Science.gov (United States)

    Ardré, Maxime; Henry, Hervé; Douarche, Carine; Plapp, Mathis

    2015-12-10

    The bacterium Bacillus subtilis frequently forms biofilms at the interface between the culture medium and the air. We present a mathematical model that couples a description of bacteria as individual discrete objects to the standard advection-diffusion equations for the environment. The model takes into account two different bacterial phenotypes. In the motile state, bacteria swim and perform a run-and-tumble motion that is biased toward regions of high oxygen concentration (aerotaxis). In the matrix-producer state they excrete extracellular polymers, which allows them to connect to other bacteria and to form a biofilm. Bacteria are also advected by the fluid, and can trigger bioconvection. Numerical simulations of the model reproduce all the stages of biofilm formation observed in laboratory experiments. Finally, we study the influence of various model parameters on the dynamics and morphology of biofilms.

  20. Performability assessment by model checking of Markov reward models

    NARCIS (Netherlands)

    Baier, Christel; Cloth, L.; Haverkort, Boudewijn R.H.M.; Hermanns, H.; Katoen, Joost P.

    2010-01-01

    This paper describes efficient procedures for model checking Markov reward models, that allow us to evaluate, among others, the performability of computer-communication systems. We present the logic CSRL (Continuous Stochastic Reward Logic) to specify performability measures. It provides flexibility

  1. Analysing the temporal dynamics of model performance for hydrological models

    NARCIS (Netherlands)

    Reusser, D.E.; Blume, T.; Schaefli, B.; Zehe, E.

    2009-01-01

    The temporal dynamics of hydrological model performance gives insights into errors that cannot be obtained from global performance measures assigning a single number to the fit of a simulated time series to an observed reference series. These errors can include errors in data, model parameters, or

  2. Analytical performance modeling for computer systems

    CERN Document Server

    Tay, Y C

    2013-01-01

    This book is an introduction to analytical performance modeling for computer systems, i.e., writing equations to describe their performance behavior. It is accessible to readers who have taken college-level courses in calculus and probability, networking and operating systems. This is not a training manual for becoming an expert performance analyst. Rather, the objective is to help the reader construct simple models for analyzing and understanding the systems that they are interested in.Describing a complicated system abstractly with mathematical equations requires a careful choice of assumpti

  3. 20 CFR 410.686b - Fee for services performed for an individual before the Social Security Administration.

    Science.gov (United States)

    2010-04-01

    ... Representation of Parties § 410.686b Fee for services performed for an individual before the Social Security... person or in writing; (ii) There was a death or serious illness in the individual's family; (iii...

  4. Performance modeling, loss networks, and statistical multiplexing

    CERN Document Server

    Mazumdar, Ravi

    2009-01-01

    This monograph presents a concise mathematical approach for modeling and analyzing the performance of communication networks with the aim of understanding the phenomenon of statistical multiplexing. The novelty of the monograph is the fresh approach and insights provided by a sample-path methodology for queueing models that highlights the important ideas of Palm distributions associated with traffic models and their role in performance measures. Also presented are recent ideas of large buffer, and many sources asymptotics that play an important role in understanding statistical multiplexing. I

  5. Cognitive control over memory - individual differences in memory performance for emotional and neutral material.

    Science.gov (United States)

    Wierzba, M; Riegel, M; Wypych, M; Jednoróg, K; Grabowska, A; Marchewka, A

    2018-02-28

    It is widely accepted that people differ in memory performance. The ability to control one's memory depends on multiple factors, including the emotional properties of the memorized material. While it was widely demonstrated that emotion can facilitate memory, it is unclear how emotion modifies our ability to suppress memory. One of the reasons for the lack of consensus among researchers is that individual differences in memory performance were largely neglected in previous studies. We used the directed forgetting paradigm in an fMRI study, in which subjects viewed neutral and emotional words, which they were instructed to remember or to forget. Subsequently, subjects' memory of these words was tested. Finally, they assessed the words on scales of valence, arousal, sadness and fear. We found that memory performance depended on instruction as reflected in the engagement of the lateral prefrontal cortex (lateral PFC), irrespective of emotional properties of words. While the lateral PFC engagement did not differ between neutral and emotional conditions, it correlated with behavioural performance when emotional - as opposed to neutral - words were presented. A deeper understanding of the underlying brain mechanisms is likely to require a study of individual differences in cognitive abilities to suppress memory.

  6. Performance of Brazilian Companies: Year Effects, Line of Business and Individual Firms

    Directory of Open Access Journals (Sweden)

    Luiz Artur Ledur Brito

    2004-07-01

    Full Text Available Performance varies. This simple statement conceals many intricacies of strategic management. Because performance varies among individual firms, researchers can explore factors that differentiate these firms and explain why some firms are consistently outperforming others. Because performance varies among industries, researchers can explore structural characteristics of different branches of accounting as a source of explanation. Because performance varies with time, researchers can explore environmental and internal dynamic elements that drive strategic decision-making. In reality,measuring and analyzing performance is a very complicated issue when performance varies simultaneously from firm to firm, from industry to industry and from year to year. The theoretical discussion behind this question is the relative importance of the industrial organization derived approach to strategy versus the resource-based view. This paper analyzes the composition of performance variance of a set of Brazilian firms from 1998 to 2001. The results demonstrate that firm effects are still dominant, with year and industry effects being lower, as previous studies with North American firms have indicated.

  7. Shock circle model for ejector performance evaluation

    International Nuclear Information System (INIS)

    Zhu, Yinhai; Cai, Wenjian; Wen, Changyun; Li, Yanzhong

    2007-01-01

    In this paper, a novel shock circle model for the prediction of ejector performance at the critical mode operation is proposed. By introducing the 'shock circle' at the entrance of the constant area chamber, a 2D exponential expression for velocity distribution is adopted to approximate the viscosity flow near the ejector inner wall. The advantage of the 'shock circle' analysis is that the calculation of ejector performance is independent of the flows in the constant area chamber and diffuser. Consequently, the calculation is even simpler than many 1D modeling methods and can predict the performance of critical mode operation ejectors much more accurately. The effectiveness of the method is validated by two experimental results reported earlier. The proposed modeling method using two coefficients is shown to produce entrainment ratio, efficiency and coefficient of performance (COP) accurately and much closer to experimental results than those of 1D analysis methods

  8. Advances in HTGR fuel performance models

    International Nuclear Information System (INIS)

    Stansfield, O.M.; Goodin, D.T.; Hanson, D.L.; Turner, R.F.

    1985-01-01

    Advances in HTGR fuel performance models have improved the agreement between observed and predicted performance and contributed to an enhanced position of the HTGR with regard to investment risk and passive safety. Heavy metal contamination is the source of about 55% of the circulating activity in the HTGR during normal operation, and the remainder comes primarily from particles which failed because of defective or missing buffer coatings. These failed particles make up about 5 x 10 -4 fraction of the total core inventory. In addition to prediction of fuel performance during normal operation, the models are used to determine fuel failure and fission product release during core heat-up accident conditions. The mechanistic nature of the models, which incorporate all important failure modes, permits the prediction of performance from the relatively modest accident temperatures of a passively safe HTGR to the much more severe accident conditions of the larger 2240-MW/t HTGR. (author)

  9. Performance Evaluation Model for Application Layer Firewalls.

    Science.gov (United States)

    Xuan, Shichang; Yang, Wu; Dong, Hui; Zhang, Jiangchuan

    2016-01-01

    Application layer firewalls protect the trusted area network against information security risks. However, firewall performance may affect user experience. Therefore, performance analysis plays a significant role in the evaluation of application layer firewalls. This paper presents an analytic model of the application layer firewall, based on a system analysis to evaluate the capability of the firewall. In order to enable users to improve the performance of the application layer firewall with limited resources, resource allocation was evaluated to obtain the optimal resource allocation scheme in terms of throughput, delay, and packet loss rate. The proposed model employs the Erlangian queuing model to analyze the performance parameters of the system with regard to the three layers (network, transport, and application layers). Then, the analysis results of all the layers are combined to obtain the overall system performance indicators. A discrete event simulation method was used to evaluate the proposed model. Finally, limited service desk resources were allocated to obtain the values of the performance indicators under different resource allocation scenarios in order to determine the optimal allocation scheme. Under limited resource allocation, this scheme enables users to maximize the performance of the application layer firewall.

  10. Performance Evaluation Model for Application Layer Firewalls.

    Directory of Open Access Journals (Sweden)

    Shichang Xuan

    Full Text Available Application layer firewalls protect the trusted area network against information security risks. However, firewall performance may affect user experience. Therefore, performance analysis plays a significant role in the evaluation of application layer firewalls. This paper presents an analytic model of the application layer firewall, based on a system analysis to evaluate the capability of the firewall. In order to enable users to improve the performance of the application layer firewall with limited resources, resource allocation was evaluated to obtain the optimal resource allocation scheme in terms of throughput, delay, and packet loss rate. The proposed model employs the Erlangian queuing model to analyze the performance parameters of the system with regard to the three layers (network, transport, and application layers. Then, the analysis results of all the layers are combined to obtain the overall system performance indicators. A discrete event simulation method was used to evaluate the proposed model. Finally, limited service desk resources were allocated to obtain the values of the performance indicators under different resource allocation scenarios in order to determine the optimal allocation scheme. Under limited resource allocation, this scheme enables users to maximize the performance of the application layer firewall.

  11. Tailored model abstraction in performance assessments

    International Nuclear Information System (INIS)

    Kessler, J.H.

    1995-01-01

    Total System Performance Assessments (TSPAs) are likely to be one of the most significant parts of making safety cases for the continued development and licensing of geologic repositories for the disposal of spent fuel and HLW. Thus, it is critical that the TSPA model capture the 'essence' of the physical processes relevant to demonstrating the appropriate regulation is met. But how much detail about the physical processes must be modeled and understood before there is enough confidence that the appropriate essence has been captured? In this summary the level of model abstraction that is required is discussed. Approaches for subsystem and total system performance analyses are outlined, and the role of best estimate models is examined. It is concluded that a conservative approach for repository performance, based on limited amount of field and laboratory data, can provide sufficient confidence for a regulatory decision

  12. Departure time choice: Modelling individual preferences, intention and constraints

    DEFF Research Database (Denmark)

    Thorhauge, Mikkel

    by nearly all studies within departure time. More importantly it shows that the underlying psychological processes are more complex than simply accounting for attitudes and perceptions which are typically used in other areas. The work in this PhD thesis accounts for the full Theory of Planned Behaviour......, but can also be perceived by the individuals as barriers towards participating in activities. Perceived constraints affect the departure time choice through the individual intention of being on time. This PhD thesis also contributes to the departure time literature by discussing the problem of collecting...... whether they are constrained. The thesis also provides empirical evidences of the policy implication of not accounting for other activities and their constraints. Thirdly, the thesis shows that the departure time choice can be partly explained by psychological factors, which have previously been neglected...

  13. Job crafting: Towards a new model of individual job redesign

    Directory of Open Access Journals (Sweden)

    Maria Tims

    2010-12-01

    Research purpose: The purpose of the study was to fit job crafting in job design theory. Motivation for the study: The study was an attempt to shed more light on the types of proactive behaviours of individual employees at work. Moreover, we explored the concept of job crafting and its antecedents and consequences. Research design, approach and method: A literature study was conducted in which the focus was first on proactive behaviour of the employee and then on job crafting. Main findings: Job crafting can be seen as a specific form of proactive behaviour in which the employee initiates changes in the level of job demands and job resources. Job crafting may be facilitated by job and individual characteristics and may enable employees to fit their jobs to their personal knowledge, skills and abilities on the one hand and to their preferences and needs on the other hand. Practical/managerial implications: Job crafting may be a good way for employees to improve their work motivation and other positive work outcomes. Employees could be encouraged to exert more influence on their job characteristics. Contribution/value-add: This article describes a relatively new perspective on active job redesign by the individual, called job crafting, which has important implications for job design theories.

  14. Effect of upper body plyometric training on physical performance in healthy individuals: A systematic review.

    Science.gov (United States)

    Singla, Deepika; Hussain, M Ejaz; Moiz, Jamal Ali

    2018-01-01

    To determine the impact of upper body plyometric training (UBPT) on physical performance parameters such as strength, ball throwing speed, ball throw distance and power in healthy individuals. PubMed, Scopus, ResearchGate and ERIC databases were searched up to August 2017. Selection of articles was done if they described the outcomes of an upper body plyometric exercise intervention; included measures of strength, ball throwing speed, ball throw distance, or power; included healthy individuals; used a randomized control trial; and had full text available in English language. The exclusion criteria were unpublished research work and clubbing of UBPT with some other type(s) of training apart from routine sports training. PEDro scale was used to rate the quality of studies eligible for this review. Initially 264 records were identified and out of them only 11 articles met the eligibility criteria and were selected (PEDro score = 4 to 6). Though large to very small effects observed in improving ball throwing velocity, ball throwing distance, power and strength of upper limb muscles after UBPT, the results should be implemented with caution. Inconclusive results obtained preclude any strong conclusion regarding the efficacy of UBPT on physical performance in healthy individuals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Impact of a poka-yoke device on job performance of individuals with cognitive impairments.

    Science.gov (United States)

    Erlandson, R F; Noblett, M J; Phelps, J A

    1998-09-01

    Job performance and production related issues are important not only to successful vocational training and ultimate job placement for individuals with cognitive disabilities, but also for their ability to have expanded vocational options. This study hypothesized that the application of Kaizen philosophy, and poka-yoke techniques in particular, could create job opportunities and improve productivity of individuals with cognitive disabilities. Poka-yoke or error-proofing techniques are part of the collection of Kaizen techniques. Kaizen refers to continuous improvement in performance, cost/effectiveness, and quality. Kaizen strives to empower the worker, increase worker satisfaction, facilitate a sense of accomplishment, and thereby create pride-of-work. These techniques typically reduce the physical and cognitive demands of a task and thereby render the task more accessible. The job was a fuel clamp assembly. A redesigned assembly fixture was the poka-yoke intervention. Consistent with poka-yoke principles, the intervention improved the productivity of everyone attempting the assembly. In particular, the workers in this study showed an 80% increase in productivity and an average percent error drop from 52% to about 1% after the process redesign. Furthermore, the workers showed improved morale, self-esteem, and pride-of-work. Prior to the process redesign, only the higher functioning workers could successfully perform the assembly. After the redesign a greater number of workers could successfully perform the assembly. These results not only validated the study hypothesis, but demonstrated that the success facilitated by applying Kaizen techniques had similar results with individuals with cognitive disabilities as with nondisabled workers.

  16. [Electronic and structural properties of individual nanometer-size supported metallic clusters]. Final performance report

    Energy Technology Data Exchange (ETDEWEB)

    Reifenberger, R.

    1993-09-01

    This report summarizes the work performed under contract DOE-FCO2-84ER45162. During the past ten years, our study of electron emission from laser-illuminated field emission tips has taken on a broader scope by addressing problems of direct interest to those concerned with the unique physical and chemical properties of nanometer-size clusters. The work performed has demonstrated that much needed data can be obtained on individual nanometer-size clusters supported on a wide-variety of different substrates. The work was performed in collaboration with R.P. Andres in the School of Chemical Engineering at Purdue University. The Multiple Expansion Cluster Source developed by Andres and his students was essential for producing the nanometer-size clusters studied. The following report features a discussion of these results. This report provides a motivation for studying the properties of nanometer-size clusters and summarizes the results obtained.

  17. Speed and lateral inhibition of stimulus processing contribute to individual differences in Stroop-task performance

    Directory of Open Access Journals (Sweden)

    Marnix eNaber

    2016-06-01

    Full Text Available The Stroop task is a popular neuropsychological test that measures executive control. Strong Stroop interference is commonly interpreted in neuropsychology as a diagnostic marker of an impairment in executive control, possibly reflecting executive dysfunction. However, popular models of the Stroop task indicate that several other aspects of colour and word processing may also account for individual differences in the Stroop task, independent of executive control. Here we use new approaches to investigate the degree to which individual differences in Stroop interference correlate with the relative processing speed of word and colour stimuli, and the lateral inhibition between visual stimuli. We conducted an electrophysiological and behavioural experiment to measure (1 how quickly an individual’s brain processes words and colours presented in isolation (P3 latency, and (2 the strength of an individual’s lateral inhibition between visual representations with a visual illusion. Both measures explained at least 40% of the variance in Stroop interference across individuals. As these measures were obtained in contexts not requiring any executive control, we conclude that the Stroop effect also measures an individual’s pre-set way of processing visual features such as words and colours. This study highlights the important contributions of stimulus processing speed and lateral inhibition to individual differences in Stroop interference, and challenges the general view that the Stroop task primarily assesses executive control.

  18. Global precedence effects account for individual differences in both face and object recognition performance.

    Science.gov (United States)

    Gerlach, Christian; Starrfelt, Randi

    2018-03-20

    There has been an increase in studies adopting an individual difference approach to examine visual cognition and in particular in studies trying to relate face recognition performance with measures of holistic processing (the face composite effect and the part-whole effect). In the present study we examine whether global precedence effects, measured by means of non-face stimuli in Navon's paradigm, can also account for individual differences in face recognition and, if so, whether the effect is of similar magnitude for faces and objects. We find evidence that global precedence effects facilitate both face and object recognition, and to a similar extent. Our results suggest that both face and object recognition are characterized by a coarse-to-fine temporal dynamic, where global shape information is derived prior to local shape information, and that the efficiency of face and object recognition is related to the magnitude of the global precedence effect.

  19. Critical review of glass performance modeling

    International Nuclear Information System (INIS)

    Bourcier, W.L.

    1994-07-01

    Borosilicate glass is to be used for permanent disposal of high-level nuclear waste in a geologic repository. Mechanistic chemical models are used to predict the rate at which radionuclides will be released from the glass under repository conditions. The most successful and useful of these models link reaction path geochemical modeling programs with a glass dissolution rate law that is consistent with transition state theory. These models have been used to simulate several types of short-term laboratory tests of glass dissolution and to predict the long-term performance of the glass in a repository. Although mechanistically based, the current models are limited by a lack of unambiguous experimental support for some of their assumptions. The most severe problem of this type is the lack of an existing validated mechanism that controls long-term glass dissolution rates. Current models can be improved by performing carefully designed experiments and using the experimental results to validate the rate-controlling mechanisms implicit in the models. These models should be supported with long-term experiments to be used for model validation. The mechanistic basis of the models should be explored by using modern molecular simulations such as molecular orbital and molecular dynamics to investigate both the glass structure and its dissolution process

  20. Critical review of glass performance modeling

    Energy Technology Data Exchange (ETDEWEB)

    Bourcier, W.L. [Lawrence Livermore National Lab., CA (United States)

    1994-07-01

    Borosilicate glass is to be used for permanent disposal of high-level nuclear waste in a geologic repository. Mechanistic chemical models are used to predict the rate at which radionuclides will be released from the glass under repository conditions. The most successful and useful of these models link reaction path geochemical modeling programs with a glass dissolution rate law that is consistent with transition state theory. These models have been used to simulate several types of short-term laboratory tests of glass dissolution and to predict the long-term performance of the glass in a repository. Although mechanistically based, the current models are limited by a lack of unambiguous experimental support for some of their assumptions. The most severe problem of this type is the lack of an existing validated mechanism that controls long-term glass dissolution rates. Current models can be improved by performing carefully designed experiments and using the experimental results to validate the rate-controlling mechanisms implicit in the models. These models should be supported with long-term experiments to be used for model validation. The mechanistic basis of the models should be explored by using modern molecular simulations such as molecular orbital and molecular dynamics to investigate both the glass structure and its dissolution process.

  1. A model to assess the emission of individual isoprenoids emitted from Italian ecosystems

    Science.gov (United States)

    Kemper Pacheco, C. J.; Fares, S.; Loreto, F.; Ciccioli, P.

    2012-04-01

    The aim of this work was to develop a GIS-based model to estimate the emissions from the Italian forest ecosystems. The model was aimed at generating a species-specific emission inventory for isoprene and individual monoterpenes that could have been validated with experimental data collected in selected sites of the CARBOITALY network. The model was develop for the year 2006. At a resolution of 1 km2 with a daily time resolution. By using the emission rates of individual components obtained through several laboratory and field experiments carried out on different vegetation species of the Mediterranean basin, maps of individual isoprenoids were generated for the Italian ecosystems. The spatial distribution and fractional contents of vegetation species present in the Italian forest ecosystems was obtained by combining the CORINE IV land cover map with National Forest Inventory based on ground observations performed at local levels by individual Italian regions (22) in which the country is divided. In general, basal emission rates for individual isoprenoids was reported by Steinbrecher et al. 1997 and Karl et al. 2009 were used. In this case, classes were further subdivided into T and L+T emitters as functions of the active pool. In many instances, however they were revised based on the results obtained in our Institute through determinations performed at leaf, branch (cuvette method) or ecosystem level (REA and the gradient method). In the latter case, studies performed in Italy and/or Mediterranean countries were used. An empirical light extinction function as a function of the canopy type and structure was introduced. The algorithms proposed by (Guenther et al. 1993) were used, but, they were often adapted to fit with the experimental observations made in the Mediterranean Areas. They were corrected for a seasonality factor (Steinbrecher et al. 2009) taking into account a time lag in leaf sprouting due to the plant elevation. A simple parameterization with LAI was

  2. Individual plant examination program: Perspectives on reactor safety and plant performance. Part 6, appendices A, B, and C

    International Nuclear Information System (INIS)

    1997-12-01

    This report provides perspectives gained by reviewing 75 Individual Plant Examination (IPE) submittals pertaining to 108 nuclear power plant units. IPEs are probabilistic analyses that estimate the core damage frequency (CDF) and containment performance for accidents initiated by internal events (including internal flooding, but excluding internal fire). The U.S. Nuclear Regulatory Commission (NRC), Office of Nuclear Regulatory Research, reviewed the WE submittals with the objective of gaining perspectives in three major areas: (1) improvements made to individual plants as a result of their IPEs and the collective results of the IPE program, (2) plant-specific design and operational features and modeling assumptions that significantly affect the estimates of CDF and containment performance, and (3) strengths and weaknesses of the models and methods used in the IPEs. These perspectives are gained by assessing the core damage and containment performance results, including overall CDF, accident sequences, dominant contributions to component failure and human error, and containment failure modes. In particular, these results are assessed in relation to the design and operational characteristics of the various reactor and containment types, and by comparing the IPEs to probabilistic risk assessment characteristics. Methods, data, boundary conditions, and assumptions used in the IPEs are considered in understanding the differences and similarities observed among the various types of plants

  3. Age and individual sleep characteristics affect cognitive performance in anesthesiology residents after a 24-hour shift.

    Science.gov (United States)

    Tadinac, Meri; Sekulić, Ante; Hromatko, Ivana; Mazul-Sunko, Branka; Ivancić, Romina

    2014-03-01

    Previous research has shown that both shift work and sleep deprivation have an adverse influence on various aspects of human cognitive performance. The aim of this study was to explore changes in cognitive functioning and subjective sleepiness of anesthesiology residents after a 24-hour shift. Twenty-six anesthesiology residents completed a set of psychological instruments at the beginning and at the end of the shift, as well as a questionnaire regarding information about the shift, Stanford Sleepiness Scale, and Circadian Type Questionnaire. There was a significant decline in cognitive performance measured by the Auditory Verbal Learning Test after the shift. The effect was stronger in older participants and in those with high scores on rigidity of sleep scale and low scores on the ability to overcome sleepiness scale. There were no differences in the digits forward test (a measure of concentration), while digits backward test (a measure of working memory) even showed an improved performance after the shift. Although participants reported being significantly sleepier after the shift, the subjective sleepiness did not correlate with any of the objective measures of cognitive performance. In conclusion, the performance in short tasks involving concentration and working memory was not impaired, while performance in long-term and monotone tasks declined after sleep deprivation, and the magnitude of this decline depended on the specific individual characteristics of sleep and on age Surprisingly, age seemed to have an important impact on cognitive functions after shift work even in the relatively age-homogeneous population of young anesthesiology residents.

  4. Evaluating physician performance at individualizing care: a pilot study tracking contextual errors in medical decision making.

    Science.gov (United States)

    Weiner, Saul J; Schwartz, Alan; Yudkowsky, Rachel; Schiff, Gordon D; Weaver, Frances M; Goldberg, Julie; Weiss, Kevin B

    2007-01-01

    Clinical decision making requires 2 distinct cognitive skills: the ability to classify patients' conditions into diagnostic and management categories that permit the application of research evidence and the ability to individualize or-more specifically-to contextualize care for patients whose circumstances and needs require variation from the standard approach to care. The purpose of this study was to develop and test a methodology for measuring physicians' performance at contextualizing care and compare it to their performance at planning biomedically appropriate care. First, the authors drafted 3 cases, each with 4 variations, 3 of which are embedded with biomedical and/or contextual information that is essential to planning care. Once the cases were validated as instruments for assessing physician performance, 54 internal medicine residents were then presented with opportunities to make these preidentified biomedical or contextual errors, and data were collected on information elicitation and error making. The case validation process was successful in that, in the final iteration, the physicians who received the contextual variant of cases proposed an alternate plan of care to those who received the baseline variant 100% of the time. The subsequent piloting of these validated cases unmasked previously unmeasured differences in physician performance at contextualizing care. The findings, which reflect the performance characteristics of the study population, are presented. This pilot study demonstrates a methodology for measuring physician performance at contextualizing care and illustrates the contribution of such information to an overall assessment of physician practice.

  5. How motivation affects academic performance: a structural equation modelling analysis.

    Science.gov (United States)

    Kusurkar, R A; Ten Cate, Th J; Vos, C M P; Westers, P; Croiset, G

    2013-03-01

    Few studies in medical education have studied effect of quality of motivation on performance. Self-Determination Theory based on quality of motivation differentiates between Autonomous Motivation (AM) that originates within an individual and Controlled Motivation (CM) that originates from external sources. To determine whether Relative Autonomous Motivation (RAM, a measure of the balance between AM and CM) affects academic performance through good study strategy and higher study effort and compare this model between subgroups: males and females; students selected via two different systems namely qualitative and weighted lottery selection. Data on motivation, study strategy and effort was collected from 383 medical students of VU University Medical Center Amsterdam and their academic performance results were obtained from the student administration. Structural Equation Modelling analysis technique was used to test a hypothesized model in which high RAM would positively affect Good Study Strategy (GSS) and study effort, which in turn would positively affect academic performance in the form of grade point averages. This model fit well with the data, Chi square = 1.095, df = 3, p = 0.778, RMSEA model fit = 0.000. This model also fitted well for all tested subgroups of students. Differences were found in the strength of relationships between the variables for the different subgroups as expected. In conclusion, RAM positively correlated with academic performance through deep strategy towards study and higher study effort. This model seems valid in medical education in subgroups such as males, females, students selected by qualitative and weighted lottery selection.

  6. Models used to assess the performance of photovoltaic systems.

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Joshua S.; Klise, Geoffrey T.

    2009-12-01

    This report documents the various photovoltaic (PV) performance models and software developed and utilized by researchers at Sandia National Laboratories (SNL) in support of the Photovoltaics and Grid Integration Department. In addition to PV performance models, hybrid system and battery storage models are discussed. A hybrid system using other distributed sources and energy storage can help reduce the variability inherent in PV generation, and due to the complexity of combining multiple generation sources and system loads, these models are invaluable for system design and optimization. Energy storage plays an important role in reducing PV intermittency and battery storage models are used to understand the best configurations and technologies to store PV generated electricity. Other researcher's models used by SNL are discussed including some widely known models that incorporate algorithms developed at SNL. There are other models included in the discussion that are not used by or were not adopted from SNL research but may provide some benefit to researchers working on PV array performance, hybrid system models and energy storage. The paper is organized into three sections to describe the different software models as applied to photovoltaic performance, hybrid systems, and battery storage. For each model, there is a description which includes where to find the model, whether it is currently maintained and any references that may be available. Modeling improvements underway at SNL include quantifying the uncertainty of individual system components, the overall uncertainty in modeled vs. measured results and modeling large PV systems. SNL is also conducting research into the overall reliability of PV systems.

  7. Performance modeling, stochastic networks, and statistical multiplexing

    CERN Document Server

    Mazumdar, Ravi R

    2013-01-01

    This monograph presents a concise mathematical approach for modeling and analyzing the performance of communication networks with the aim of introducing an appropriate mathematical framework for modeling and analysis as well as understanding the phenomenon of statistical multiplexing. The models, techniques, and results presented form the core of traffic engineering methods used to design, control and allocate resources in communication networks.The novelty of the monograph is the fresh approach and insights provided by a sample-path methodology for queueing models that highlights the importan

  8. A statistical model for predicting muscle performance

    Science.gov (United States)

    Byerly, Diane Leslie De Caix

    The objective of these studies was to develop a capability for predicting muscle performance and fatigue to be utilized for both space- and ground-based applications. To develop this predictive model, healthy test subjects performed a defined, repetitive dynamic exercise to failure using a Lordex spinal machine. Throughout the exercise, surface electromyography (SEMG) data were collected from the erector spinae using a Mega Electronics ME3000 muscle tester and surface electrodes placed on both sides of the back muscle. These data were analyzed using a 5th order Autoregressive (AR) model and statistical regression analysis. It was determined that an AR derived parameter, the mean average magnitude of AR poles, significantly correlated with the maximum number of repetitions (designated Rmax) that a test subject was able to perform. Using the mean average magnitude of AR poles, a test subject's performance to failure could be predicted as early as the sixth repetition of the exercise. This predictive model has the potential to provide a basis for improving post-space flight recovery, monitoring muscle atrophy in astronauts and assessing the effectiveness of countermeasures, monitoring astronaut performance and fatigue during Extravehicular Activity (EVA) operations, providing pre-flight assessment of the ability of an EVA crewmember to perform a given task, improving the design of training protocols and simulations for strenuous International Space Station assembly EVA, and enabling EVA work task sequences to be planned enhancing astronaut performance and safety. Potential ground-based, medical applications of the predictive model include monitoring muscle deterioration and performance resulting from illness, establishing safety guidelines in the industry for repetitive tasks, monitoring the stages of rehabilitation for muscle-related injuries sustained in sports and accidents, and enhancing athletic performance through improved training protocols while reducing

  9. Dynamic working memory performance in individuals with single-domain amnestic mild cognitive impairment.

    Science.gov (United States)

    Guild, Emma B; Vasquez, Brandon P; Maione, Andrea M; Mah, Linda; Ween, Jon; Anderson, Nicole D

    2014-01-01

    Previous studies have observed poorer working memory performance in individuals with amnestic mild cognitive impairment than in healthy older adults. It is unclear, however, whether these difficulties are true only of the multiple-domain clinical subtype in whom poorer executive functioning is common. The current study examined working memory, as measured by the self-ordered pointing task (SOPT) and an n-back task, in healthy older adults and adults with single-domain amnestic mild cognitive impairment (aMCI). Individuals with single-domain aMCI committed more errors and required longer to develop an organizational strategy on the SOPT. The single-domain aMCI group did not differ from healthy older adults on the 1-back or 2-back, but had poorer discrimination on the 3-back task. This is, to our knowledge, the first characterization of dynamic working memory performance in a single-domain aMCI group. These results lend support for the idea that clinical amnestic MCI subtypes may reflect different stages on a continuum of progression to dementia and question whether standardized measures of working memory (span tasks) are sensitive enough to capture subtle changes in performance.

  10. Subjective overachievement: individual differences in self-doubt and concern with performance.

    Science.gov (United States)

    Oleson, K C; Poehlmann, K M; Yost, J H; Lynch, M E; Arkin, R M

    2000-06-01

    We discuss the construct of doubt about one's competence and suggest that doubt can have myriad consequences (e.g., self-handicapping, defensive pessimism). We focus on the effect of self-doubt when it is combined with a concern with performance and assert that this combination leads to the phenomenon of subjective overachievement. In two studies, we present a new 17-item Subjective Overachievement Scale (SOS), which includes two independent subscales measuring individual differences in self-doubt and concern with performance. The first study, consisting of two large samples (Ns = 2,311 and 1,703), provides evidence that the scale has high internal consistency and a clear two-factor structure. Additionally, the subscales have adequate test-retest reliability (Ns = 67 and 115). A second study reveals that the SOS has good convergent and discriminant validity. Both subscales are unrelated to social desirability but exhibit the predicted patterns of associations with other related constructs. The Concern with Performance Subscale is correlated with achievement motivation, whereas the Self-Doubt Subscale is correlated with scales assessing negative affectivity (e.g., self-esteem, social anxiety) and other self-related strategies associated with concerns about one's competence (e.g., self-handicapping, defensive pessimism, impostor phenomenon). The SOS, which combines the two subscales, appears to tap a unique strategy that individuals may use to deal with doubts about their own competence.

  11. Relationship between touch sensation of the affected hand and performance of valued activities in individuals with chronic stroke.

    Science.gov (United States)

    Hill, Valerie A; Fisher, Thomas; Schmid, Arlene A; Crabtree, Jeffrey; Page, Stephen J

    2014-01-01

    To investigate the association between touch sensation of the affected hand and performance and satisfaction with performance of valued activities in individuals with chronic stroke. Using a cross-sectional study design, this study correlated factors related to hand sensation and activity performance in individuals with chronic stroke. The Touch Test Evaluators and Canadian Occupational Performance Measure (COPM) were used. Correlations were used to determine the relationships between touch sensation of the affected hand and individuals' performance and satisfaction with performance of valued activities. There was a good to excellent relationship between sensation and performance and satisfaction with performance of valued activities for individuals with intact touch sensation of the affected hand who scored higher on the COPM. There was little to no relationship between touch sensation of the affected hand and performance of valued activities for individuals with impaired sensation. This is the first study to relate touch sensation of the affected hand and performance and satisfaction with performance of valued activities in individuals with stroke. The findings suggest that rehabilitation therapists need to continue to address sensory function in evaluation and intervention as it relates to performance in valued activities. This study serves as a foundation for future research in sensation and performance of valued activities in individuals with chronic stroke.

  12. Computational Models of Individual Differences in Working Memory Capacity

    National Research Council Canada - National Science Library

    Frankel, Gerald

    2002-01-01

    ...) because the attack in Al alloys seems to transition into IGC as it grows. A statistical model to describe the effect of microstructure on the IG path length and thus penetration rate was developed...

  13. Development and Validation of a Prediction Model to Estimate Individual Risk of Pancreatic Cancer.

    Science.gov (United States)

    Yu, Ami; Woo, Sang Myung; Joo, Jungnam; Yang, Hye-Ryung; Lee, Woo Jin; Park, Sang-Jae; Nam, Byung-Ho

    2016-01-01

    There is no reliable screening tool to identify people with high risk of developing pancreatic cancer even though pancreatic cancer represents the fifth-leading cause of cancer-related death in Korea. The goal of this study was to develop an individualized risk prediction model that can be used to screen for asymptomatic pancreatic cancer in Korean men and women. Gender-specific risk prediction models for pancreatic cancer were developed using the Cox proportional hazards model based on an 8-year follow-up of a cohort study of 1,289,933 men and 557,701 women in Korea who had biennial examinations in 1996-1997. The performance of the models was evaluated with respect to their discrimination and calibration ability based on the C-statistic and Hosmer-Lemeshow type χ2 statistic. A total of 1,634 (0.13%) men and 561 (0.10%) women were newly diagnosed with pancreatic cancer. Age, height, BMI, fasting glucose, urine glucose, smoking, and age at smoking initiation were included in the risk prediction model for men. Height, BMI, fasting glucose, urine glucose, smoking, and drinking habit were included in the risk prediction model for women. Smoking was the most significant risk factor for developing pancreatic cancer in both men and women. The risk prediction model exhibited good discrimination and calibration ability, and in external validation it had excellent prediction ability. Gender-specific risk prediction models for pancreatic cancer were developed and validated for the first time. The prediction models will be a useful tool for detecting high-risk individuals who may benefit from increased surveillance for pancreatic cancer.

  14. Aircraft Anomaly Detection Using Performance Models Trained on Fleet Data

    Science.gov (United States)

    Gorinevsky, Dimitry; Matthews, Bryan L.; Martin, Rodney

    2012-01-01

    This paper describes an application of data mining technology called Distributed Fleet Monitoring (DFM) to Flight Operational Quality Assurance (FOQA) data collected from a fleet of commercial aircraft. DFM transforms the data into aircraft performance models, flight-to-flight trends, and individual flight anomalies by fitting a multi-level regression model to the data. The model represents aircraft flight performance and takes into account fixed effects: flight-to-flight and vehicle-to-vehicle variability. The regression parameters include aerodynamic coefficients and other aircraft performance parameters that are usually identified by aircraft manufacturers in flight tests. Using DFM, the multi-terabyte FOQA data set with half-million flights was processed in a few hours. The anomalies found include wrong values of competed variables, (e.g., aircraft weight), sensor failures and baises, failures, biases, and trends in flight actuators. These anomalies were missed by the existing airline monitoring of FOQA data exceedances.

  15. The Influence of Proactive Socialization Behaviors and Team Socialization on Individual Performance in the Team

    Science.gov (United States)

    Pennaforte, Antoine

    2016-01-01

    On the basis of the role and the social exchange theories, this research investigated the direct and indirect antecedents of three dimensions of team performance (proficiency, adaptivity, proactivity) developed through cooperative education. The theoretical model examined how proactive socialization behaviors led to team socialization and team…

  16. Wave and Wind Model Performance Metrics Tools

    Science.gov (United States)

    Choi, J. K.; Wang, D. W.

    2016-02-01

    Continual improvements and upgrades of Navy ocean wave and wind models are essential to the assurance of battlespace environment predictability of ocean surface wave and surf conditions in support of Naval global operations. Thus, constant verification and validation of model performance is equally essential to assure the progress of model developments and maintain confidence in the predictions. Global and regional scale model evaluations may require large areas and long periods of time. For observational data to compare against, altimeter winds and waves along the tracks from past and current operational satellites as well as moored/drifting buoys can be used for global and regional coverage. Using data and model runs in previous trials such as the planned experiment, the Dynamics of the Adriatic in Real Time (DART), we demonstrated the use of accumulated altimeter wind and wave data over several years to obtain an objective evaluation of the performance the SWAN (Simulating Waves Nearshore) model running in the Adriatic Sea. The assessment provided detailed performance of wind and wave models by using cell-averaged statistical variables maps with spatial statistics including slope, correlation, and scatter index to summarize model performance. Such a methodology is easily generalized to other regions and at global scales. Operational technology currently used by subject matter experts evaluating the Navy Coastal Ocean Model and the Hybrid Coordinate Ocean Model can be expanded to evaluate wave and wind models using tools developed for ArcMAP, a GIS application developed by ESRI. Recent inclusion of altimeter and buoy data into a format through the Naval Oceanographic Office's (NAVOCEANO) quality control system and the netCDF standards applicable to all model output makes it possible for the fusion of these data and direct model verification. Also, procedures were developed for the accumulation of match-ups of modelled and observed parameters to form a data base

  17. Generating Performance Models for Irregular Applications

    Energy Technology Data Exchange (ETDEWEB)

    Friese, Ryan D.; Tallent, Nathan R.; Vishnu, Abhinav; Kerbyson, Darren J.; Hoisie, Adolfy

    2017-05-30

    Many applications have irregular behavior --- non-uniform input data, input-dependent solvers, irregular memory accesses, unbiased branches --- that cannot be captured using today's automated performance modeling techniques. We describe new hierarchical critical path analyses for the \\Palm model generation tool. To create a model's structure, we capture tasks along representative MPI critical paths. We create a histogram of critical tasks with parameterized task arguments and instance counts. To model each task, we identify hot instruction-level sub-paths and model each sub-path based on data flow, instruction scheduling, and data locality. We describe application models that generate accurate predictions for strong scaling when varying CPU speed, cache speed, memory speed, and architecture. We present results for the Sweep3D neutron transport benchmark; Page Rank on multiple graphs; Support Vector Machine with pruning; and PFLOTRAN's reactive flow/transport solver with domain-induced load imbalance.

  18. Measurement-based reliability/performability models

    Science.gov (United States)

    Hsueh, Mei-Chen

    1987-01-01

    Measurement-based models based on real error-data collected on a multiprocessor system are described. Model development from the raw error-data to the estimation of cumulative reward is also described. A workload/reliability model is developed based on low-level error and resource usage data collected on an IBM 3081 system during its normal operation in order to evaluate the resource usage/error/recovery process in a large mainframe system. Thus, both normal and erroneous behavior of the system are modeled. The results provide an understanding of the different types of errors and recovery processes. The measured data show that the holding times in key operational and error states are not simple exponentials and that a semi-Markov process is necessary to model the system behavior. A sensitivity analysis is performed to investigate the significance of using a semi-Markov process, as opposed to a Markov process, to model the measured system.

  19. Individual plant examination program: Perspectives on reactor safety and plant performance. Parts 2--5: Final report; Volume 2

    International Nuclear Information System (INIS)

    1997-12-01

    This report provides perspectives gained by reviewing 75 Individual Plant Examination (IPE) submittals pertaining to 108 nuclear power plant units. IPEs are probabilistic analyses that estimate the core damage frequency (CDF) and containment performance for accidents initiated by internal events. The US Nuclear Regulatory Commission (NRC) reviewed the IPE submittals with the objective of gaining perspectives in three major areas: (1) improvements made to individual plants as a result of their IPEs and the collective results of the IPE program, (2) plant-specific design and operational features and modeling assumptions that significantly affect the estimates of CDF and containment performance, and (3) strengths and weaknesses of the models and methods used in the IPEs. These perspectives are gained by assessing the core damage and containment performance results, including overall CDF, accident sequences, dominant contributions to component failure and human error, and containment failure modes. Methods, data, boundary conditions, and assumptions used in the IPEs are considered in understanding the differences and similarities observed among the various types of plants. This report is divided into three volumes containing six parts. Part 1 is a summary report of the key perspectives gained in each of the areas identified above, with a discussion of the NRC's overall conclusions and observations. Part 2 discusses key perspectives regarding the impact of the IPE Program on reactor safety. Part 3 discusses perspectives gained from the IPE results regarding CDF, containment performance, and human actions. Part 4 discusses perspectives regarding the IPE models and methods. Part 5 discusses additional IPE perspectives. Part 6 contains Appendices A, B and C which provide the references of the information from the IPEs, updated PRA results, and public comments on draft NUREG-1560 respectively

  20. Individual plant examination program: Perspectives on reactor safety and plant performance. Part 1: Final summary report; Volume 1

    International Nuclear Information System (INIS)

    1997-12-01

    This report provides perspectives gained by reviewing 75 Individual Plant Examination (IPE) submittals pertaining to 108 nuclear power plant units. IPEs are probabilistic analyses that estimate the core damage frequency (CDF) and containment performance for accidents initiated by internal events. The US Nuclear Regulatory Commission (NRC) reviewed the IPE submittals with the objective of gaining perspectives in three major areas: (1) improvements made to individual plants as a result of their IPEs and the collective results of the IPE program, (2) plant-specific design and operational features and modeling assumptions that significantly affect the estimates of CDF and containment performance, and (3) strengths and weaknesses of the models and methods used in the IPEs. These perspectives are gained by assessing the core damage and containment performance results, including overall CDF, accident sequences, dominant contributions to component failure and human error, and containment failure modes. Methods, data, boundary conditions, and assumptions used in the IPEs are considered in understanding the differences and similarities observed among the various types of plants. This report is divided into three volumes containing six parts. Part 1 is a summary report of the key perspectives gained in each of the areas identified above, with a discussion of the NRC's overall conclusions and observations. Part 2 discusses key perspectives regarding the impact of the IPE Program on reactor safety. Part 3 discusses perspectives gained from the IPE results regarding CDF, containment performance, and human actions. Part 4 discusses perspectives regarding the IPE models and methods. Part 5 discusses additional IPE perspectives. Part 6 contains Appendices A, B and C which provide the references of the information from the IPEs, updated PRA results, and public comments on draft NUREG-1560 respectively

  1. Individual plant examination program: Perspectives on reactor safety and plant performance. Parts 2--5: Final report; Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-01

    This report provides perspectives gained by reviewing 75 Individual Plant Examination (IPE) submittals pertaining to 108 nuclear power plant units. IPEs are probabilistic analyses that estimate the core damage frequency (CDF) and containment performance for accidents initiated by internal events. The US Nuclear Regulatory Commission (NRC) reviewed the IPE submittals with the objective of gaining perspectives in three major areas: (1) improvements made to individual plants as a result of their IPEs and the collective results of the IPE program, (2) plant-specific design and operational features and modeling assumptions that significantly affect the estimates of CDF and containment performance, and (3) strengths and weaknesses of the models and methods used in the IPEs. These perspectives are gained by assessing the core damage and containment performance results, including overall CDF, accident sequences, dominant contributions to component failure and human error, and containment failure modes. Methods, data, boundary conditions, and assumptions used in the IPEs are considered in understanding the differences and similarities observed among the various types of plants. This report is divided into three volumes containing six parts. Part 1 is a summary report of the key perspectives gained in each of the areas identified above, with a discussion of the NRC`s overall conclusions and observations. Part 2 discusses key perspectives regarding the impact of the IPE Program on reactor safety. Part 3 discusses perspectives gained from the IPE results regarding CDF, containment performance, and human actions. Part 4 discusses perspectives regarding the IPE models and methods. Part 5 discusses additional IPE perspectives. Part 6 contains Appendices A, B and C which provide the references of the information from the IPEs, updated PRA results, and public comments on draft NUREG-1560 respectively.

  2. Individual discriminative face recognition models based on subsets of features

    DEFF Research Database (Denmark)

    Clemmensen, Line Katrine Harder; Gomez, David Delgado; Ersbøll, Bjarne Kjær

    2007-01-01

    The accuracy of data classification methods depends considerably on the data representation and on the selected features. In this work, the elastic net model selection is used to identify meaningful and important features in face recognition. Modelling the characteristics which distinguish one...... person from another using only subsets of features will both decrease the computational cost and increase the generalization capacity of the face recognition algorithm. Moreover, identifying which are the features that better discriminate between persons will also provide a deeper understanding...... of the face recognition problem. The elastic net model is able to select a subset of features with low computational effort compared to other state-of-the-art feature selection methods. Furthermore, the fact that the number of features usually is larger than the number of images in the data base makes feature...

  3. Developing population models with data from marked individuals

    Science.gov (United States)

    Hae Yeong Ryu,; Kevin T. Shoemaker,; Eva Kneip,; Anna Pidgeon,; Patricia Heglund,; Brooke Bateman,; Thogmartin, Wayne E.; Reşit Akçakaya,

    2016-01-01

    Population viability analysis (PVA) is a powerful tool for biodiversity assessments, but its use has been limited because of the requirements for fully specified population models such as demographic structure, density-dependence, environmental stochasticity, and specification of uncertainties. Developing a fully specified population model from commonly available data sources – notably, mark–recapture studies – remains complicated due to lack of practical methods for estimating fecundity, true survival (as opposed to apparent survival), natural temporal variability in both survival and fecundity, density-dependence in the demographic parameters, and uncertainty in model parameters. We present a general method that estimates all the key parameters required to specify a stochastic, matrix-based population model, constructed using a long-term mark–recapture dataset. Unlike standard mark–recapture analyses, our approach provides estimates of true survival rates and fecundities, their respective natural temporal variabilities, and density-dependence functions, making it possible to construct a population model for long-term projection of population dynamics. Furthermore, our method includes a formal quantification of parameter uncertainty for global (multivariate) sensitivity analysis. We apply this approach to 9 bird species and demonstrate the feasibility of using data from the Monitoring Avian Productivity and Survivorship (MAPS) program. Bias-correction factors for raw estimates of survival and fecundity derived from mark–recapture data (apparent survival and juvenile:adult ratio, respectively) were non-negligible, and corrected parameters were generally more biologically reasonable than their uncorrected counterparts. Our method allows the development of fully specified stochastic population models using a single, widely available data source, substantially reducing the barriers that have until now limited the widespread application of PVA. This method

  4. Performance Measurement Model A TarBase model with ...

    Indian Academy of Sciences (India)

    rohit

    Model A 8.0 2.0 94.52% 88.46% 76 108 12 12 0.86 0.91 0.78 0.94. Model B 2.0 2.0 93.18% 89.33% 64 95 10 9 0.88 0.90 0.75 0.98. The above results for TEST – 1 show details for our two models (Model A and Model B).Performance of Model A after adding of 32 negative dataset of MiRTif on our testing set(MiRecords) ...

  5. A Procurement Performance Model for Construction Frameworks

    Directory of Open Access Journals (Sweden)

    Terence Y M Lam

    2015-07-01

    Full Text Available Collaborative construction frameworks have been developed in the United Kingdom (UK to create longer term relationships between clients and suppliers in order to improve project outcomes. Research undertaken into highways maintenance set within a major county council has confirmed that such collaborative procurement methods can improve time, cost and quality of construction projects. Building upon this and examining the same single case, this research aims to develop a performance model through identification of performance drivers in the whole project delivery process including pre and post contract phases. A priori performance model based on operational and sociological constructs was proposed and then checked by a pilot study. Factor analysis and central tendency statistics from the questionnaires as well as content analysis from the interview transcripts were conducted. It was confirmed that long term relationships, financial and non-financial incentives and stronger communication are the sociological behaviour factors driving performance. The interviews also established that key performance indicators (KPIs can be used as an operational measure to improve performance. With the posteriori performance model, client project managers can effectively collaboratively manage contractor performance through procurement measures including use of longer term and KPIs for the contract so that the expected project outcomes can be achieved. The findings also make significant contribution to construction framework procurement theory by identifying the interrelated sociological and operational performance drivers. This study is set predominantly in the field of highways civil engineering. It is suggested that building based projects or other projects that share characteristics are grouped together and used for further research of the phenomena discovered.

  6. Models for Automated Tube Performance Calculations

    International Nuclear Information System (INIS)

    Brunkhorst, C.

    2002-01-01

    High power radio-frequency systems, as typically used in fusion research devices, utilize vacuum tubes. Evaluation of vacuum tube performance involves data taken from tube operating curves. The acquisition of data from such graphical sources is a tedious process. A simple modeling method is presented that will provide values of tube currents for a given set of element voltages. These models may be used as subroutines in iterative solutions of amplifier operating conditions for a specific loading impedance

  7. Improved reading performance using individualized compensation filters for observers with losses in central vision

    Science.gov (United States)

    Lawton, Teri B.

    1989-01-01

    A method to improve the reading performance of subjects with losses in central vision is proposed in which the amplitudes of the intermediate spatial frequencies are boosted relative to the lower spatial frequencies. In the method, words are filtered using an image enhancement function which is based on a subject's losses in visual function relative to a normal subject. It was found that 30-70 percent less magnification was necessary, and that reading rates were improved 2-3 times, using the method. The individualized compensation filters improved the clarity and visibility of words. The shape of the enhancement function was shown to be important in determining the optimum compensation filter for improving reading performance.

  8. Performance Evaluation and Modelling of Container Terminals

    Science.gov (United States)

    Venkatasubbaiah, K.; Rao, K. Narayana; Rao, M. Malleswara; Challa, Suresh

    2018-02-01

    The present paper evaluates and analyzes the performance of 28 container terminals of south East Asia through data envelopment analysis (DEA), principal component analysis (PCA) and hybrid method of DEA-PCA. DEA technique is utilized to identify efficient decision making unit (DMU)s and to rank DMUs in a peer appraisal mode. PCA is a multivariate statistical method to evaluate the performance of container terminals. In hybrid method, DEA is integrated with PCA to arrive the ranking of container terminals. Based on the composite ranking, performance modelling and optimization of container terminals is carried out through response surface methodology (RSM).

  9. Potential contributions of training intensity on locomotor performance in individuals with chronic stroke.

    Science.gov (United States)

    Holleran, Carey L; Rodriguez, Kelly S; Echauz, Anthony; Leech, Kristan A; Hornby, T George

    2015-04-01

    Many interventions can improve walking ability of individuals with stroke, although the training parameters that maximize recovery are not clear. For example, the contribution of training intensity has not been well established and may contribute to the efficacy of many locomotor interventions. The purpose of this preliminary study was to evaluate the effects of locomotor training intensity on walking outcomes in individuals with gait deficits poststroke. Using a randomized cross-over design, 12 participants with chronic stroke (>6-month duration) performed either high-intensity (70%-80% of heart rate reserve; n = 6) or low-intensity (30%-40% heart rate reserve; n = 6) locomotor training for 12 or fewer sessions over 4 to 5 weeks. Four weeks following completion, the alternate training intervention was performed. Training intensity was manipulated by adding loads or applying resistance during walking, with similar speeds, durations, and amount of stepping practice between conditions. Greater increases in 6-Minute Walk Test performance were observed following high-intensity training compared with low-intensity training. A significant interaction of intensity and order was also observed for 6-Minute Walk Test and peak treadmill speed, with the largest changes in those who performed high-intensity training first. Moderate correlations were observed between locomotor outcomes and measures of training intensity. This study provides the first evidence that the intensity of locomotor practice may be an important independent determinant of walking outcomes poststroke. In the clinical setting, the intensity of locomotor training can be manipulated in many ways, although this represents only 1 parameter to consider.Video Abstract available for more insights from the authors (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A90).

  10. Individualized Human CAD Models: Anthropmetric Morphing and Body Tissue Layering

    Science.gov (United States)

    2014-07-31

    fat thickness may not be uniform and an estimation of this inhomogeneity is integrated into the sub-assemblies of the CAD model. For example, the...Xu X, Endrusick T, Santee W and Kokla M. Simulation of toe thermal responses to cold exposure while wearing protective footwear . SAE 2005

  11. Markovian Building Blocks for Individual-Based Modelling

    DEFF Research Database (Denmark)

    Nilsson, Lars Anders Fredrik

    2007-01-01

    previous exposure to Markov chains in continuous time (see e.g. Grimmett and Stirzaker, 2001)). Markovian arrival processes are very general point processes that are relatively easy to analyse. They have, so far, been largely unknown to the ecological modelling community. The article C deals...

  12. Individualized computer-aided education in mammography based on user modeling: concept and preliminary experiments.

    Science.gov (United States)

    Mazurowski, Maciej A; Baker, Jay A; Barnhart, Huiman X; Tourassi, Georgia D

    2010-03-01

    The authors propose the framework for an individualized adaptive computer-aided educational system in mammography that is based on user modeling. The underlying hypothesis is that user models can be developed to capture the individual error making patterns of radiologists-in-training. In this pilot study, the authors test the above hypothesis for the task of breast cancer diagnosis in mammograms. The concept of a user model was formalized as the function that relates image features to the likelihood/extent of the diagnostic error made by a radiologist-in-training and therefore to the level of difficulty that a case will pose to the radiologist-in-training (or "user"). Then, machine learning algorithms were implemented to build such user models. Specifically, the authors explored k-nearest neighbor, artificial neural networks, and multiple regression for the task of building the model using observer data collected from ten Radiology residents at Duke University Medical Center for the problem of breast mass diagnosis in mammograms. For each resident, a user-specific model was constructed that predicts the user's expected level of difficulty for each presented case based on two BI-RADS image features. In the experiments, leave-one-out data handling scheme was applied to assign each case to a low-predicted-difficulty or a high-predicted-difficulty group for each resident based on each of the three user models. To evaluate whether the user model is useful in predicting difficulty, the authors performed statistical tests using the generalized estimating equations approach to determine whether the mean actual error is the same or not between the low-predicted-difficulty group and the high-predicted-difficulty group. When the results for all observers were pulled together, the actual errors made by residents were statistically significantly higher for cases in the high-predicted-difficulty group than for cases in the low-predicted-difficulty group for all modeling

  13. Modeling Feedbacks Between Individual Human Decisions and Hydrology Using Interconnected Physical and Social Models

    Science.gov (United States)

    Murphy, J.; Lammers, R. B.; Proussevitch, A. A.; Ozik, J.; Altaweel, M.; Collier, N. T.; Alessa, L.; Kliskey, A. D.

    2014-12-01

    The global hydrological cycle intersects with human decision making at multiple scales, from dams and irrigation works to the taps in individuals' homes. Residential water consumers are commonly encouraged to conserve; these messages are heard against a background of individual values and conceptions about water quality, uses, and availability. The degree to which these values impact the larger-hydrological dynamics, the way that changes in those values have impacts on the hydrological cycle through time, and the feedbacks by which water availability and quality in turn shape those values, are not well explored. To investigate this domain we employ a global-scale water balance model (WBM) coupled with a social-science-grounded agent-based model (ABM). The integration of a hydrological model with an agent-based model allows us to explore driving factors in the dynamics in coupled human-natural systems. From the perspective of the physical hydrologist, the ABM offers a richer means of incorporating the human decisions that drive the hydrological system; from the view of the social scientist, a physically-based hydrological model allows the decisions of the agents to play out against constraints faithful to the real world. We apply the interconnected models to a study of Tucson, Arizona, USA, and its role in the larger Colorado River system. Our core concept is Technology-Induced Environmental Distancing (TIED), which posits that layers of technology can insulate consumers from direct knowledge of a resource. In Tucson, multiple infrastructure and institutional layers have arguably increased the conceptual distance between individuals and their water supply, offering a test case of the TIED framework. Our coupled simulation allows us to show how the larger system transforms a resource with high temporal and spatial variability into a consumer constant, and the effects of this transformation on the regional system. We use this to explore how pricing, messaging, and

  14. Sensitivity analysis of an individual-based model for simulation of influenza epidemics.

    Directory of Open Access Journals (Sweden)

    Elaine O Nsoesie

    Full Text Available Individual-based epidemiology models are increasingly used in the study of influenza epidemics. Several studies on influenza dynamics and evaluation of intervention measures have used the same incubation and infectious period distribution parameters based on the natural history of influenza. A sensitivity analysis evaluating the influence of slight changes to these parameters (in addition to the transmissibility would be useful for future studies and real-time modeling during an influenza pandemic.In this study, we examined individual and joint effects of parameters and ranked parameters based on their influence on the dynamics of simulated epidemics. We also compared the sensitivity of the model across synthetic social networks for Montgomery County in Virginia and New York City (and surrounding metropolitan regions with demographic and rural-urban differences. In addition, we studied the effects of changing the mean infectious period on age-specific epidemics. The research was performed from a public health standpoint using three relevant measures: time to peak, peak infected proportion and total attack rate. We also used statistical methods in the design and analysis of the experiments. The results showed that: (i minute changes in the transmissibility and mean infectious period significantly influenced the attack rate; (ii the mean of the incubation period distribution appeared to be sufficient for determining its effects on the dynamics of epidemics; (iii the infectious period distribution had the strongest influence on the structure of the epidemic curves; (iv the sensitivity of the individual-based model was consistent across social networks investigated in this study and (v age-specific epidemics were sensitive to changes in the mean infectious period irrespective of the susceptibility of the other age groups. These findings suggest that small changes in some of the disease model parameters can significantly influence the uncertainty

  15. The effect of additional joint mobilization on neuromuscular performance in individuals with functional ankle instability.

    Science.gov (United States)

    Shih, Yi-Fen; Yu, Hsiang-Ting; Chen, Wen-Yin; Liao, Kwong-Kum; Lin, Hsiu-Chen; Yang, Yea-Ru

    2018-03-01

    To examine the effects of joint mobilization and exercise training on neuromuscular performance in individuals with functional ankle instability (FAI). A cross-sectional study. Forty five subjects with FAI were randomized into three groups: control (CG, n = 15, 27.9 ± 6.6yr), training (TG, n = 15, 26.9 ± 5.8yr) and mobilization with training group (MTG, n = 15, 26.5 ± 4.8yr). Four weeks of neuromuscular training for TG; neuromuscular training and joint mobilization for MTG. Electromyography of the peroneus longus (PL), tibialis anterior (TA), and soleus (SOL) and the reaching distance of the Y balance test (YBT), dorsiflexion range of motion (DFROM), Cumberland ankle instability tool (CAIT), and global rating scale (GRS). Two-way repeated measures MANOVA were used with the significance level p Joint mobilization resulted in additional benefits on self-reported ankle instability severity, dorsiflexion mobility, and posterolateral balance performance in individuals with FAI, but its effects on general improvement, muscle activation, and other balance tasks remained uncertain. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Utilities for high performance dispersion model PHYSIC

    International Nuclear Information System (INIS)

    Yamazawa, Hiromi

    1992-09-01

    The description and usage of the utilities for the dispersion calculation model PHYSIC were summarized. The model was developed in the study of developing high performance SPEEDI with the purpose of introducing meteorological forecast function into the environmental emergency response system. The procedure of PHYSIC calculation consists of three steps; preparation of relevant files, creation and submission of JCL, and graphic output of results. A user can carry out the above procedure with the help of the Geographical Data Processing Utility, the Model Control Utility, and the Graphic Output Utility. (author)

  17. Effect of respiratory muscle training on exercise performance in healthy individuals: a systematic review and meta-analysis.

    Science.gov (United States)

    Illi, Sabine K; Held, Ulrike; Frank, Irène; Spengler, Christina M

    2012-08-01

    Two distinct types of specific respiratory muscle training (RMT), i.e. respiratory muscle strength (resistive/threshold) and endurance (hyperpnoea) training, have been established to improve the endurance performance of healthy individuals. We performed a systematic review and meta-analysis in order to determine the factors that affect the change in endurance performance after RMT in healthy subjects. A computerized search was performed without language restriction in MEDLINE, EMBASE and CINAHL and references of original studies and reviews were searched for further relevant studies. RMT studies with healthy individuals assessing changes in endurance exercise performance by maximal tests (constant load, time trial, intermittent incremental, conventional [non-intermittent] incremental) were screened and abstracted by two independent investigators. A multiple linear regression model was used to identify effects of subjects' fitness, type of RMT (inspiratory or combined inspiratory/expiratory muscle strength training, respiratory muscle endurance training), type of exercise test, test duration and type of sport (rowing, running, swimming, cycling) on changes in performance after RMT. In addition, a meta-analysis was performed to determine the effect of RMT on endurance performance in those studies providing the necessary data. The multiple linear regression analysis including 46 original studies revealed that less fit subjects benefit more from RMT than highly trained athletes (6.0% per 10 mL · kg⁻¹ · min⁻¹ decrease in maximal oxygen uptake, 95% confidence interval [CI] 1.8, 10.2%; p = 0.005) and that improvements do not differ significantly between inspiratory muscle strength and respiratory muscle endurance training (p = 0.208), while combined inspiratory and expiratory muscle strength training seems to be superior in improving performance, although based on only 6 studies (+12.8% compared with inspiratory muscle strength training, 95% CI 3

  18. A practical model for sustainable operational performance

    International Nuclear Information System (INIS)

    Vlek, C.A.J.; Steg, E.M.; Feenstra, D.; Gerbens-Leenis, W.; Lindenberg, S.; Moll, H.; Schoot Uiterkamp, A.; Sijtsma, F.; Van Witteloostuijn, A.

    2002-01-01

    By means of a concrete model for sustainable operational performance enterprises can report uniformly on the sustainability of their contributions to the economy, welfare and the environment. The development and design of a three-dimensional monitoring system is presented and discussed [nl

  19. Intercomparison of performance characteristics of OSLDs and TLDs used for individual monitoring

    International Nuclear Information System (INIS)

    Meye, Phillipe Ondo

    2016-07-01

    This research work performed an intercomparison on some important performance characteristics of optically stimulated luminescence (OSL) and thermoluminescence (TL) dosimetry systems used by dosimetry services in Gabon and Ghana, respectively. The study verified the status of the selected performance indicators and propose ways to improve the performances of individual monitoring services of Ghana and Gabon if found necessary. The performance indicators assessed included the zero - dose, the minimum detectability and some important reader performance characteristics. These tests were performed using statistical and experimental methods. The overall uncertainty in measurement of the dosimetry systems of Ghana and Gabon for Hp(10) was determined using the IEC technical report TR 62461, and comparisons were carried out with IAEA 99, PTB 99, IEC 1066 and IEC1283 series performance standards. The IEC 62387 standard was used to assess the linearity dependence of the response and the coefficient of variation of the two dosimetry systems. For the Harshaw TLD 6600 system of the dosimetry service of Ghana, the Reference light QC test meets the requirement given in the user manual. For the OSL system microStar of the dosimetry system of Gabon, the three QC tests, DRK count, CAL count and LED count, meet the user manual requirements. However all these tests failed the statistical test that is part of counting statistics. This led to the conclusion that there may be some abnormalities in the counting system, and that the statistical abnormalities suspected have apparently no impact on the results of the reading. It was also concluded that since the DRK count and the CAL count failed the Chi - squared test by very small margin, a Gaussian distribution could still be considered as an approximation of the experimental data distributions of these two QC measurements. The zero dose for the Harshaw 6600 and the microStar system were found to be 0.026 mSv and 0.08 mSv respectively

  20. Data Model Performance in Data Warehousing

    Science.gov (United States)

    Rorimpandey, G. C.; Sangkop, F. I.; Rantung, V. P.; Zwart, J. P.; Liando, O. E. S.; Mewengkang, A.

    2018-02-01

    Data Warehouses have increasingly become important in organizations that have large amount of data. It is not a product but a part of a solution for the decision support system in those organizations. Data model is the starting point for designing and developing of data warehouses architectures. Thus, the data model needs stable interfaces and consistent for a longer period of time. The aim of this research is to know which data model in data warehousing has the best performance. The research method is descriptive analysis, which has 3 main tasks, such as data collection and organization, analysis of data and interpretation of data. The result of this research is discussed in a statistic analysis method, represents that there is no statistical difference among data models used in data warehousing. The organization can utilize four data model proposed when designing and developing data warehouse.

  1. Acceleration performance of individual European sea bass Dicentrarchus labrax measured with a sprint performance chamber: comparison with high-speed cinematography and correlates with ecological performance.

    Science.gov (United States)

    Vandamm, Joshua P; Marras, Stefano; Claireaux, Guy; Handelsman, Corey A; Nelson, Jay A

    2012-01-01

    Locomotor performance can influence the ecological and evolutionary success of a species. For fish, favorable outcomes of predator-prey encounters are often presumably due to robust acceleration ability. Although escape-response or "fast-start" studies utilizing high-speed cinematography are prevalent, little is known about the contribution of relative acceleration performance to ecological or evolutionary success in a species. This dearth of knowledge may be due to the time-consuming nature of analyzing film, which imposes a practical limit on sample sizes. Herein, we present a high-throughput potential alternative for measuring fish acceleration performance using a sprint performance chamber (SPC). The acceleration performance of a large number of juvenile European sea bass (Dicentrarchus labrax) from two populations was analyzed. Animals from both hatchery and natural ontogenies were assessed, and animals of known acceleration ability had their ecological performance measured in a mesocosm environment. Individuals from one population also had their acceleration performance assessed by both high-speed cinematography and an SPC. Acceleration performance measured in an SPC was lower than that measured by classical high-speed video techniques. However, short-term repeatability and interindividual variation of acceleration performance were similar between the two techniques, and the SPC recorded higher sprint swimming velocities. Wild fish were quicker to accelerate in an SPC and had significantly greater accelerations than all groups of hatchery-raised fish. Acceleration performance had no significant effect on ecological performance (as assessed through animal growth and survival in the mesocosms). However, it is worth noting that wild animals did survive predation in the mesocosm better than farmed ones. Moreover, the hatchery-originated fish that survived the mesocosm experiment, when no predators were present, displayed significantly increased acceleration

  2. Comparison of Simple Versus Performance-Based Fall Prediction Models

    Directory of Open Access Journals (Sweden)

    Shekhar K. Gadkaree BS

    2015-05-01

    Full Text Available Objective: To compare the predictive ability of standard falls prediction models based on physical performance assessments with more parsimonious prediction models based on self-reported data. Design: We developed a series of fall prediction models progressing in complexity and compared area under the receiver operating characteristic curve (AUC across models. Setting: National Health and Aging Trends Study (NHATS, which surveyed a nationally representative sample of Medicare enrollees (age ≥65 at baseline (Round 1: 2011-2012 and 1-year follow-up (Round 2: 2012-2013. Participants: In all, 6,056 community-dwelling individuals participated in Rounds 1 and 2 of NHATS. Measurements: Primary outcomes were 1-year incidence of “ any fall ” and “ recurrent falls .” Prediction models were compared and validated in development and validation sets, respectively. Results: A prediction model that included demographic information, self-reported problems with balance and coordination, and previous fall history was the most parsimonious model that optimized AUC for both any fall (AUC = 0.69, 95% confidence interval [CI] = [0.67, 0.71] and recurrent falls (AUC = 0.77, 95% CI = [0.74, 0.79] in the development set. Physical performance testing provided a marginal additional predictive value. Conclusion: A simple clinical prediction model that does not include physical performance testing could facilitate routine, widespread falls risk screening in the ambulatory care setting.

  3. Performance model for a CCTV-MTI

    International Nuclear Information System (INIS)

    Dunn, D.R.; Dunbar, D.L.

    1978-01-01

    CCTV-MTI (closed circuit television--moving target indicator) monitors represent typical components of access control systems, as for example in a material control and accounting (MC and A) safeguards system. This report describes a performance model for a CCTV-MTI monitor. The performance of a human in an MTI role is a separate problem and is not addressed here. This work was done in conjunction with the NRC sponsored LLL assessment procedure for MC and A systems which is presently under development. We develop a noise model for a generic camera system and a model for the detection mechanism for a postulated MTI design. These models are then translated into an overall performance model. Measures of performance are probabilities of detection and false alarm as a function of intruder-induced grey level changes in the protected area. Sensor responsivity, lens F-number, source illumination and spectral response were treated as design parameters. Some specific results are illustrated for a postulated design employing a camera with a Si-target vidicon. Reflectance or light level changes in excess of 10% due to an intruder will be detected with a very high probability for the portion of the visible spectrum with wavelengths above 500 nm. The resulting false alarm rate was less than one per year. We did not address sources of nuisance alarms due to adverse environments, reliability, resistance to tampering, nor did we examine the effects of the spatial frequency response of the optics. All of these are important and will influence overall system detection performance

  4. Profit-Based Model Selection for Customer Retention Using Individual Customer Lifetime Values.

    Science.gov (United States)

    Óskarsdóttir, María; Baesens, Bart; Vanthienen, Jan

    2018-03-01

    The goal of customer retention campaigns, by design, is to add value and enhance the operational efficiency of businesses. For organizations that strive to retain their customers in saturated, and sometimes fast moving, markets such as the telecommunication and banking industries, implementing customer churn prediction models that perform well and in accordance with the business goals is vital. The expected maximum profit (EMP) measure is tailored toward this problem by taking into account the costs and benefits of a retention campaign and estimating its worth for the organization. Unfortunately, the measure assumes fixed and equal customer lifetime value (CLV) for all customers, which has been shown to not correspond well with reality. In this article, we extend the EMP measure to take into account the variability in the lifetime values of customers, thereby basing it on individual characteristics. We demonstrate how to incorporate the heterogeneity of CLVs when CLVs are known, when their prior distribution is known, and when neither is known. By taking into account individual CLVs, our proposed approach of measuring model performance gives novel insights when deciding on a customer retention campaign. The method is dependent on the characteristics of the customer base as is compliant with modern business analytics and accommodates the data-driven culture that has manifested itself within organizations.

  5. Variation in Primary Cesarean Delivery Rates by Individual Physician within a Single Hospital Laborist Model

    Science.gov (United States)

    METZ, Torri D.; ALLSHOUSE, Amanda A.; GILBERT, Sara A Babcock; DOYLE, Reina; TONG, Angie; CAREY, J. Christopher

    2016-01-01

    Background Laborist practice models are associated with lower cesarean delivery rates than individual private practice models in several studies; however, this effect is not uniform. Further exploration of laborist models may help us better understand the observed reduction in cesarean delivery rates in some hospitals with implementation of a laborist model. Objective Our objective was to evaluate the degree of variation in primary cesarean delivery rates by individual laborists within a single institution employing a laborist model. In addition, we sought to evaluate whether differences in cesarean delivery rates resulted in different maternal or short-term neonatal outcomes. Study Design At this teaching institution, one laborist (either a generalist or maternal-fetal medicine attending physician) is directly responsible for labor and delivery management during each shift. No patients are followed in a private practice model nor are physicians incentivized to perform deliveries. We retrospectively identified all laborists who delivered nulliparous, term women with cephalic singletons at this institution from 2007-14. Overall and individual primary cesarean delivery rates were reported as percentages with exact Pearson 95% CI. Laborists were grouped by tertile as having low, medium or high cesarean delivery rates. Characteristics of the women delivered, indications for cesarean delivery, and short-term neonatal outcomes were compared between these groups. A binomial regression model of cesarean delivery was estimated, where the relative rates of each laborist compared to the lowest-unadjusted laborist rate were calculated; a second model was estimated to adjust for patient-level maternal characteristics. Results Twenty laborists delivered 2,224 nulliparous, term women with cephalic singletons. The overall cesarean delivery rate was 24.1% (95% CI 21.4-26.8). In an unadjusted binomial model, the overall effect of individual laborist was significant (pcesarean

  6. Effects of caffeine ingestion on endurance performance in mentally fatigued individuals.

    Science.gov (United States)

    Azevedo, Rafael; Silva-Cavalcante, Marcos David; Gualano, Bruno; Lima-Silva, Adriano E; Bertuzzi, Romulo

    2016-12-01

    To examine the effects of caffeine ingestion on physiological and perceptual responses in mentally fatigued individuals. Eight male physically active subjects completed four cycling constant-workload tests in four experimental conditions at 80 % of maximal power output: control (C), mental fatigue (MF), mental fatigue plus caffeine ingestion (5 mg/kg) (MF-CAF), and mental fatigue plus placebo (MF-PLA). The mental fatigue was induced by a continuous performance task A-X version (AX-CPT). Before and after the AX-CPT, the profile of mood state (POMS) and blood samples for lactate measurement were collected. Oxygen consumption ([Formula: see text]), rating of perceived exertion (RPE), and electromyography (EMG) activity were measured during the cycling test. The time to exhaustion in C, MF, MF-PLA, and MF-CAF were 251 ± 30, 222 ± 23, 248 ± 28, and 285 ± 42 s, respectively. Delta values (corrected by C condition) were higher in MF-CAF than MF (P = 0.031). MF-CAF reported higher Vigor scores when compared with C (P = 0.046) and MF (P = 0.020). RPE at the first minute was significantly higher in MF-PLA than in C (P = 0.050); at the second minute, RPE was higher in MF-PLA than in C (P = 0.049) and MF-CAF (P = 0.048). EMG activity was not different between the conditions. Caffeine ingestion increased approximately 14 % endurance performance after the induction of mental fatigue. This effect was accompanied by a tendency to improvement in mood state (i.e., vigor). Therefore, caffeine ingestion can promote a beneficial effect on endurance performance in mentally fatigued individuals.

  7. Modelling the effects of environmental and individual variability when measuring the costs of first reproduction

    Directory of Open Access Journals (Sweden)

    Barbraud, C.

    2004-06-01

    higher recapture probabilities (0.528 ± 0.033 than inexperienced breeders (0.364 ± 0.019. First–time breeders had the lowest mean survival probabilities (0.775 ± 0.035, and experienced breeders had the highest mean survival probabilities (0.882 ± 0.035. Inexperienced and experienced nonbreeders had intermediate mean survival probabilities, indicating a cost of first reproduction for first time breeders. First–time breeders had a lower probability of breeding in the following year than experienced breeders, and nonbreeders had a lower probability of breeding in the following year than breeders. Among nonbreeders, inexperienced nonbreeders had a lower probability of breeding in the following year than experienced nonbreeders. A model where state survival probabilities were a function of sea surface height had the lowest QAICc. Survival of inexperienced individuals (both breeders and nonbreeders was negatively affected by poor oceanographic conditions, whereas experienced birds seem to be only weakly affected by similar conditions. The costs of reproduction for first–time breeders were particularly marked during harsh climatic conditions. Body condition of experienced breeders was higher than the body condition of first–time and nonbreeders. Body condition of individuals seen only once was lower than body condition of those seen at least twice. At the individual level, there was no clear evidence for an increase in body condition across years. These results can be interpreted in the light of the selection hypothesis (Curio, 1983; Forslund & Pärt, 1995. The inferiority of inexperienced breeders may be linked to a higher proportion of lower–quality individuals in younger age classes. First reproduction may act as a filter selecting individuals of higher quality/body mass. The improvement of performance within individuals may contribute marginally to the observed patterns at the population level. Environmental stochasticity, and more particularly the variation

  8. Modeling auditory perception of individual hearing-impaired listeners

    DEFF Research Database (Denmark)

    Jepsen, Morten Løve; Dau, Torsten

    showed that, in most cases, the reduced or absent cochlear compression, associated with outer hair-cell loss, quantitatively accounts for broadened auditory filters, while a combination of reduced compression and reduced inner hair-cell function accounts for decreased sensitivity and slower recovery from...... selectivity. Three groups of listeners were considered: (a) normal hearing listeners; (b) listeners with a mild-to-moderate sensorineural hearing loss; and (c) listeners with a severe sensorineural hearing loss. A fixed set of model parameters were derived for each hearing-impaired listener. The simulations...

  9. It Is Not Only Mentoring: The Combined Influences of Individual-Level and Team-Level Support on Job Performance

    Science.gov (United States)

    van Emmerik, I. J. Hetty

    2008-01-01

    Purpose: The paper aims to follow social exchange theory and group social capital theory, to predict positive relationships between (informal) mentoring and various support resources for two types of performance (i.e. perceptions of individual and team performance). Design/methodology/approach: The associations of individual-level mentoring and…

  10. THE USE OF NEURAL NETWORK TECHNOLOGY TO MODEL SWIMMING PERFORMANCE

    Directory of Open Access Journals (Sweden)

    António José Silva

    2007-03-01

    Full Text Available The aims of the present study were: to identify the factors which are able to explain the performance in the 200 meters individual medley and 400 meters front crawl events in young swimmers, to model the performance in those events using non-linear mathematic methods through artificial neural networks (multi-layer perceptrons and to assess the neural network models precision to predict the performance. A sample of 138 young swimmers (65 males and 73 females of national level was submitted to a test battery comprising four different domains: kinanthropometric evaluation, dry land functional evaluation (strength and flexibility, swimming functional evaluation (hydrodynamics, hydrostatic and bioenergetics characteristics and swimming technique evaluation. To establish a profile of the young swimmer non-linear combinations between preponderant variables for each gender and swim performance in the 200 meters medley and 400 meters font crawl events were developed. For this purpose a feed forward neural network was used (Multilayer Perceptron with three neurons in a single hidden layer. The prognosis precision of the model (error lower than 0.8% between true and estimated performances is supported by recent evidence. Therefore, we consider that the neural network tool can be a good approach in the resolution of complex problems such as performance modeling and the talent identification in swimming and, possibly, in a wide variety of sports

  11. Assessing The Performance of Hydrological Models

    Science.gov (United States)

    van der Knijff, Johan

    The performance of hydrological models is often characterized using the coefficient of efficiency, E. The sensitivity of E to extreme streamflow values, and the difficulty of deciding what value of E should be used as a threshold to identify 'good' models or model parameterizations, have proven to be serious shortcomings of this index. This paper reviews some alternative performance indices that have appeared in the litera- ture. Legates and McCabe (1999) suggested a more generalized form of E, E'(j,B). Here, j is a parameter that controls how much emphasis is put on extreme streamflow values, and B defines a benchmark or 'null hypothesis' against which the results of the model are tested. E'(j,B) was used to evaluate a large number of parameterizations of a conceptual rainfall-runoff model, using 6 different combinations of j and B. First, the effect of j and B is explained. Second, it is demonstrated how the index can be used to explicitly test hypotheses about the model and the data. This approach appears to be particularly attractive if the index is used as a likelihood measure within a GLUE-type analysis.

  12. Model-Based Individualized Treatment of Chemotherapeutics: Bayesian Population Modeling and Dose Optimization.

    Directory of Open Access Journals (Sweden)

    Devaraj Jayachandran

    Full Text Available 6-Mercaptopurine (6-MP is one of the key drugs in the treatment of many pediatric cancers, auto immune diseases and inflammatory bowel disease. 6-MP is a prodrug, converted to an active metabolite 6-thioguanine nucleotide (6-TGN through enzymatic reaction involving thiopurine methyltransferase (TPMT. Pharmacogenomic variation observed in the TPMT enzyme produces a significant variation in drug response among the patient population. Despite 6-MP's widespread use and observed variation in treatment response, efforts at quantitative optimization of dose regimens for individual patients are limited. In addition, research efforts devoted on pharmacogenomics to predict clinical responses are proving far from ideal. In this work, we present a Bayesian population modeling approach to develop a pharmacological model for 6-MP metabolism in humans. In the face of scarcity of data in clinical settings, a global sensitivity analysis based model reduction approach is used to minimize the parameter space. For accurate estimation of sensitive parameters, robust optimal experimental design based on D-optimality criteria was exploited. With the patient-specific model, a model predictive control algorithm is used to optimize the dose scheduling with the objective of maintaining the 6-TGN concentration within its therapeutic window. More importantly, for the first time, we show how the incorporation of information from different levels of biological chain-of response (i.e. gene expression-enzyme phenotype-drug phenotype plays a critical role in determining the uncertainty in predicting therapeutic target. The model and the control approach can be utilized in the clinical setting to individualize 6-MP dosing based on the patient's ability to metabolize the drug instead of the traditional standard-dose-for-all approach.

  13. Model-Based Individualized Treatment of Chemotherapeutics: Bayesian Population Modeling and Dose Optimization

    Science.gov (United States)

    Jayachandran, Devaraj; Laínez-Aguirre, José; Rundell, Ann; Vik, Terry; Hannemann, Robert; Reklaitis, Gintaras; Ramkrishna, Doraiswami

    2015-01-01

    6-Mercaptopurine (6-MP) is one of the key drugs in the treatment of many pediatric cancers, auto immune diseases and inflammatory bowel disease. 6-MP is a prodrug, converted to an active metabolite 6-thioguanine nucleotide (6-TGN) through enzymatic reaction involving thiopurine methyltransferase (TPMT). Pharmacogenomic variation observed in the TPMT enzyme produces a significant variation in drug response among the patient population. Despite 6-MP’s widespread use and observed variation in treatment response, efforts at quantitative optimization of dose regimens for individual patients are limited. In addition, research efforts devoted on pharmacogenomics to predict clinical responses are proving far from ideal. In this work, we present a Bayesian population modeling approach to develop a pharmacological model for 6-MP metabolism in humans. In the face of scarcity of data in clinical settings, a global sensitivity analysis based model reduction approach is used to minimize the parameter space. For accurate estimation of sensitive parameters, robust optimal experimental design based on D-optimality criteria was exploited. With the patient-specific model, a model predictive control algorithm is used to optimize the dose scheduling with the objective of maintaining the 6-TGN concentration within its therapeutic window. More importantly, for the first time, we show how the incorporation of information from different levels of biological chain-of response (i.e. gene expression-enzyme phenotype-drug phenotype) plays a critical role in determining the uncertainty in predicting therapeutic target. The model and the control approach can be utilized in the clinical setting to individualize 6-MP dosing based on the patient’s ability to metabolize the drug instead of the traditional standard-dose-for-all approach. PMID:26226448

  14. Individual recognition of social rank and social memory performance depends on a functional circadian system.

    Science.gov (United States)

    Müller, L; Weinert, D

    2016-11-01

    In a natural environment, social abilities of an animal are important for its survival. Particularly, it must recognize its own social rank and the social rank of a conspecific and have a good social memory. While the role of the circadian system for object and spatial recognition and memory is well known, the impact of the social rank and circadian disruptions on social recognition and memory were not investigated so far. In the present study, individual recognition of social rank and social memory performance of Djungarian hamsters revealing different circadian phenotypes were investigated. Wild type (WT) animals show a clear and well-synchronized daily activity rhythm, whereas in arrhythmic (AR) hamsters, the suprachiasmatic nuclei (SCN) do not generate a circadian signal. The aim of the study was to investigate putative consequences of these deteriorations in the circadian system for animalś cognitive abilities. Hamsters were bred and kept under standardized housing conditions with food and water ad libitum and a 14l/10 D lighting regimen. Experimental animals were assigned to different groups (WT and AR) according to their activity pattern obtained by means of infrared motion sensors. Before the experiments, the animals were given to develop a dominant-subordinate relationship in a dyadic encounter. Experiment 1 dealt with individual recognition of social rank. Subordinate and dominant hamsters were tested in an open arena for their behavioral responses towards a familiar (known from the agonistic encounters) or an unfamiliar hamster (from another agonistic encounter) which had the same or an opposite social rank. The investigation time depended on the social rank of the WT subject hamster and its familiarity with the stimulus animal. Both subordinate and dominant WT hamsters preferred an unfamiliar subordinate stimulus animal. In contrast, neither subordinate nor dominant AR hamsters preferred any of the stimulus animals. Thus, disruptions in circadian

  15. System Advisor Model: Flat Plate Photovoltaic Performance Modeling Validation Report

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, Janine [National Renewable Energy Lab. (NREL), Golden, CO (United States); Whitmore, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kaffine, Leah [National Renewable Energy Lab. (NREL), Golden, CO (United States); Blair, Nate [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dobos, Aron P. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-12-01

    The System Advisor Model (SAM) is a free software tool that performs detailed analysis of both system performance and system financing for a variety of renewable energy technologies. This report provides detailed validation of the SAM flat plate photovoltaic performance model by comparing SAM-modeled PV system generation data to actual measured production data for nine PV systems ranging from 75 kW to greater than 25 MW in size. The results show strong agreement between SAM predictions and field data, with annualized prediction error below 3% for all fixed tilt cases and below 8% for all one axis tracked cases. The analysis concludes that snow cover and system outages are the primary sources of disagreement, and other deviations resulting from seasonal biases in the irradiation models and one axis tracking issues are discussed in detail.

  16. Individual performance evaluation of the Brazilian Nuclear Energy Commission (CNEN): a meta-evaluative study

    International Nuclear Information System (INIS)

    Bezerra, Leonardo Ferreira

    2017-01-01

    The present study is a summative meta-evaluation that had as objective to evaluate the quality of the process of evaluation of individual performance of the servers of the National Commission of Nuclear Energy, being guided by the scientific curiosity to know to what extent the evaluation of performance the National Commission for Nuclear Energy meets the quality standards disseminated by the Joint Committee on Standards for Educational Evaluation. The methodology chosen to be used was based on the management approach and had as a guiding principle of the study the elaboration of a framework of criteria considering the aforementioned standards. The criteria established in the criteria framework guided the preparation of the items of the questionnaire sent to the National Commission of Nuclear Energy servers. In addition to the questionnaire, the observation of this author was considered in the context where the phenomenon occurred, which allowed a better reflective analysis of the data collected by the questionnaire. Regarding the results, it can be inferred that the performance evaluation developed at the National Commission of Nuclear Energy can be considered of quality, highlighting the servers' trust for the data, the communication process of the program stages, the credibility of the evaluators, the process of negotiation of goals and adaptability of the instrument over the course of the cycle. However, there are some opportunities for improvement, considering the relevance of evaluation as a tool to improve the performance of the autarchy's servers. Among the points that need to be improved is that there is currently a lack of knowledge about the legal basis and justification of the process of evaluation process by the servers and the lack of clarity regarding the content of the final evaluation report. Among the recommendations of this study, one can consider as the most relevant the need to: disseminate the results of this meta-evaluation to the

  17. Quantifying individual performance in Cricket — A network analysis of batsmen and bowlers

    Science.gov (United States)

    Mukherjee, Satyam

    2014-01-01

    Quantifying individual performance in the game of Cricket is critical for team selection in International matches. The number of runs scored by batsmen and wickets taken by bowlers serves as a natural way of quantifying the performance of a cricketer. Traditionally the batsmen and bowlers are rated on their batting or bowling average respectively. However, in a game like Cricket it is always important the manner in which one scores the runs or claims a wicket. Scoring runs against a strong bowling line-up or delivering a brilliant performance against a team with a strong batting line-up deserves more credit. A player’s average is not able to capture this aspect of the game. In this paper we present a refined method to quantify the ‘quality’ of runs scored by a batsman or wickets taken by a bowler. We explore the application of Social Network Analysis (SNA) to rate the players in a team performance. We generate a directed and weighted network of batsmen-bowlers using the player-vs-player information available for Test cricket and ODI cricket. Additionally we generate a network of batsmen and bowlers based on the dismissal record of batsmen in the history of cricket-Test (1877-2011) and ODI (1971-2011). Our results show that M. Muralitharan is the most successful bowler in the history of Cricket. Our approach could potentially be applied in domestic matches to judge a player’s performance which in turn paves the way for a balanced team selection for International matches.

  18. Multiscale Modeling and Uncertainty Quantification for Nuclear Fuel Performance

    Energy Technology Data Exchange (ETDEWEB)

    Estep, Donald [Colorado State Univ., Fort Collins, CO (United States); El-Azab, Anter [Florida State Univ., Tallahassee, FL (United States); Pernice, Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Peterson, John W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Polyakov, Peter [Univ. of Wyoming, Laramie, WY (United States); Tavener, Simon [Colorado State Univ., Fort Collins, CO (United States); Xiu, Dongbin [Purdue Univ., West Lafayette, IN (United States); Univ. of Utah, Salt Lake City, UT (United States)

    2017-03-23

    In this project, we will address the challenges associated with constructing high fidelity multiscale models of nuclear fuel performance. We (*) propose a novel approach for coupling mesoscale and macroscale models, (*) devise efficient numerical methods for simulating the coupled system, and (*) devise and analyze effective numerical approaches for error and uncertainty quantification for the coupled multiscale system. As an integral part of the project, we will carry out analysis of the effects of upscaling and downscaling, investigate efficient methods for stochastic sensitivity analysis of the individual macroscale and mesoscale models, and carry out a posteriori error analysis for computed results. We will pursue development and implementation of solutions in software used at Idaho National Laboratories on models of interest to the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program.

  19. The immediate effects of foot orthoses on functional performance in individuals with patellofemoral pain syndrome.

    Science.gov (United States)

    Barton, C J; Menz, H B; Crossley, K M

    2011-03-01

    Patellofemoral pain syndrome (PFPS) often results in reduced functional performance. There is growing evidence for the use of foot orthoses to treat this multifactorial condition. In this study, the immediate effects of foot orthoses on functional performance and the association of foot posture and footwear with improvements in function were evaluated. Fifty-two individuals with PFPS (18-35 years) were prescribed prefabricated foot orthoses (Vasyli Pro; Vasyli International, Labrador, Australia). Functional outcome measures evaluated included the change in (1) pain and (2) ease of a single-leg squat on a five-point Likert scale, and change in the number of (3) pain-free step downs and (4) single-leg rises from sitting. The association of foot posture using the Foot Posture Index, navicular drop and calcaneal angle relative to subtalar joint neutral; and the footwear motion control properties scale score with improved function were evaluated using Spearman's ρ statistics. Prefabricated foot orthoses produced significant improvements (psquat and improvements in the number of pain-free single-leg rises from sitting when wearing foot orthoses. In addition, a more pronated foot type was also found to be associated with improved ease of completing a single-leg squat when wearing foot orthoses. Prefabricated foot orthoses provide immediate improvements in functional performance, and these improvements are associated with a more pronated foot type and poorer footwear motion control properties.

  20. The Metabolic Syndrome Predicts Longitudinal Changes in Clock Drawing Test Performance in Older Nondemented Hypertensive Individuals.

    Science.gov (United States)

    Viscogliosi, Giovanni; Chiriac, Iulia Maria; Andreozzi, Paola; Ettorre, Evaristo

    2016-05-01

    The present study evaluated the metabolic syndrome (MetS) as independent predictor of 1-year longitudinal changes in cognitive function. 104 stroke- and dementia-free older hypertensive subjects were studied. MetS was defined by NCEP ATP-III criteria. Cognitive function was assessed by the Clock Drawing Test (CDT); 1-year changes in cognitive function were expressed as annual changes in CDT performance. Brain magnetic resonance imaging studies (1.5T) were performed. Participants with MetS exhibited greater cognitive decline than those without (-1.78 ± 1.47 versus -0.74 ± 1.44 CDT points, t = 3.348, df = 102, p < 0.001). MetS predicted cognitive decline (β = -0.327, t = -3.059, df = 96, p = 0.003) independently of its components, age, baseline cognition, neuroimaging findings, blood pressure levels, and duration of hypertension. With the exception of systolic blood pressure, none of the individual components of MetS explained 1-year changes in CDT performance. MetS as an entity predicted accelerated 1-year decline in cognitive function, assessed by CDT, in a sample of older hypertensive subjects. Copyright © 2016 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.

  1. Individual differences in media multitasking and performance on the n-back.

    Science.gov (United States)

    Ralph, Brandon C W; Smilek, Daniel

    2017-02-01

    A number of studies have recently examined the link between individual differences in media multitasking (using the MMI) and performance on working memory paradigms. However, these studies have yielded mixed results. Here we examine the relation between media multitasking and one particular working memory paradigm-the n-back (2- and 3-back)-improving upon previous research by (a) treating media multitasking as a continuous variable and adopting a correlational approach as well as (b) using a large sample of participants. First, we found that higher scores on the MMI were associated with a greater proportion of omitted trials on both the 2-back and 3-back, indicating that heavier media multitaskers were more disengaged during the n-back. In line with such a claim, heavier media multitaskers were also more likely to confess to responding randomly during various portions of the experiment, and to report media multitasking during the experiment itself. Importantly, when controlling for the relation between MMI scores and omissions, higher scores on the MMI were associated with an increase in false alarms, but not with a change in hits. These findings refine the extant literature on media multitasking and working memory performance (specifically, performance on the n-back), and suggest that media multitasking may be related to the propensity to disengage from ongoing tasks.

  2. Study on the transverse chromatic aberration of the individual eye model after LASIK refractive surgery

    Science.gov (United States)

    Zhang, Mei; Wang, Zhao-Qi; Wang, Yan; Zuo, Tong

    2010-10-01

    The aim of this research is to study the properties of the transverse chromatic aberration (TCA) after the LASIK refractive surgery based on the individual eye model involving the angle between visual axis and optical axis. According to the measurements of the corneal surfaces, the optical axis lengths and the wavefront aberrations, the individual eye models before and after LASIK refractive surgery are constructed for 15 eyes by using ZEMAX optic design software, while the angle between the visual axis and optical axis is calculated from the data of the anterior corneal surface. The constructed eye models are then used to investigate the variation of the TCA after the surgery. The statistical distributions of the magnitude of the foveal TCA for 15 eyes over the visible spectrum are provided. Finally, we investigate the influence of the TCA on the visual quality and compare the results with previous research. The TCA is an indispensable criterion to evaluate the performance of the refractive surgery. This research is very meaningful for the studies of not only foveal vision but also the peripheral vision.

  3. Construction of Site Risk Model using Individual Unit Risk Model in a NPP Site

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Ho Gon; Han, Sang Hoon [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    Since Fukushima accident, strong needs to estimate site risk has been increased to identify the possibility of re-occurrence of such a tremendous disaster and prevent such a disaster. Especially, in a site which has large fleet of nuclear power plants, reliable site risk assessment is very emergent to confirm the safety. In Korea, there are several nuclear power plant site which have more than 6 NPPs. In general, risk model of a NPP in terms of PSA is very complicated and furthermore, it is expected that the site risk model is more complex than that. In this paper, the method for constructing site risk model is proposed by using individual unit risk model. Procedure for the development of site damage (risk) model was proposed in the present paper. Since the site damage model is complicated in the sense of the scale of the system and dependency of the components of the system, conventional method may not be applicable in many side of the problem.

  4. Performance modeling of network data services

    Energy Technology Data Exchange (ETDEWEB)

    Haynes, R.A.; Pierson, L.G.

    1997-01-01

    Networks at major computational organizations are becoming increasingly complex. The introduction of large massively parallel computers and supercomputers with gigabyte memories are requiring greater and greater bandwidth for network data transfers to widely dispersed clients. For networks to provide adequate data transfer services to high performance computers and remote users connected to them, the networking components must be optimized from a combination of internal and external performance criteria. This paper describes research done at Sandia National Laboratories to model network data services and to visualize the flow of data from source to sink when using the data services.

  5. Effects of lighting illuminance levels on stair negotiation performance in individuals with visual impairment.

    Science.gov (United States)

    Shaheen, Aliah F; Sourlas, Alexandros; Horton, Khim; McLean, Christopher; Ewins, David; Gould, David; Ghoussayni, Salim

    2018-04-01

    Stair-related falls of older people cause a substantial financial and social burden. Deterioration of the visual system amongst other factors put older people at a high risk of falling. Improved lighting is often recommended. The aim of this study was to investigate the effect of lighting illuminance on stair negotiation performance in older individuals with visual impairment. Eleven participants aged 60 or over with a vision of 6/18 or worse ascended and descended a staircase under: 50 lx, 100 lx, 200 lx, 300 lx and distributed 200 lx lighting. A motion capture system was used to measure movements of the lower limb. Clearance, clearance variability, temporal and spatial parameters and joint/segment kinematics were computed. There was no effect on clearance or clearance variability. Participants had lower speed, cadence, increased cycle time and stance time in the 50 lx compared to 300 lx and distributed 200 lx lighting in descent. The minimum hip angle in ascent was increased in the 200 lx lighting. Clearance was found to be moderately correlated with balance scores. Individuals with visual impairment adopt precautionary gait in dim lighting conditions. This does not always result in improvements in the parameters associated with risk of falling (e.g. clearance). Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Citation analysis as a measure of article quality, journal influence and individual researcher performance

    International Nuclear Information System (INIS)

    Nightingale, Julie M.; Marshall, Gill

    2012-01-01

    The research-related performance of universities, as well as that of individual researchers, is increasingly evaluated through the use of objective measures, or metrics, which seek to support or in some cases even replace more traditional methods of peer review. In particular there is a growing awareness in research communities, government organisations and funding bodies around the concept of using evaluation metrics to analyse research citations. The tools available for ‘citation analysis’ are many and varied, enabling a quantification of scientific quality, academic impact and prestige. However there is increasing concern regarding the potential misuse of such tools, which have limitations in certain research disciplines. This article uses ‘real world’ examples from radiography research and scholarship to illustrate the range of currently available citation analysis tools. It explores the academic debate surrounding their strengths and limitations, and identifies the potential impact of citation analysis on the radiography research community. The article concludes that citation analysis is a valuable tool for researchers to use for personal reflection and research planning, yet there are inherent dangers if it is used inappropriately. Whilst citation analysis can give objective information regarding an individual, research group, journal or higher education institution, it should not be used as a total substitute for traditional qualitative review and peer assessment.

  7. Reprint of "Citation analysis as a measure of article quality, journal influence and individual researcher performance".

    Science.gov (United States)

    Nightingale, Julie M; Marshall, Gill

    2013-09-01

    The research-related performance of universities, as well as that of individual researchers, is increasingly evaluated through the use of objective measures, or metrics, which seek to support or in some cases even replace more traditional methods of peer review. In particular there is a growing awareness in research communities, government organisations and funding bodies around the concept of using evaluation metrics to analyse research citations. The tools available for 'citation analysis' are many and varied, enabling a quantification of scientific quality, academic impact and prestige. However there is increasing concern regarding the potential misuse of such tools, which have limitations in certain research disciplines.This article uses 'real world' examples from radiography research and scholarship to illustrate the range of currently available citation analysis tools. It explores the academic debate surrounding their strengths and limitations, and identifies the potential impact of citation analysis on the radiography research community.The article concludes that citation analysis is a valuable tool for researchers to use for personal reflection and research planning, yet there are inherent dangers if it is used inappropriately. Whilst citation analysis can give objective information regarding an individual, research group, journal or higher education institution, it should not be used as a total substitute for traditional qualitative review and peer assessment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Probabilistic Radiological Performance Assessment Modeling and Uncertainty

    Science.gov (United States)

    Tauxe, J.

    2004-12-01

    A generic probabilistic radiological Performance Assessment (PA) model is presented. The model, built using the GoldSim systems simulation software platform, concerns contaminant transport and dose estimation in support of decision making with uncertainty. Both the U.S. Nuclear Regulatory Commission (NRC) and the U.S. Department of Energy (DOE) require assessments of potential future risk to human receptors of disposal of LLW. Commercially operated LLW disposal facilities are licensed by the NRC (or agreement states), and the DOE operates such facilities for disposal of DOE-generated LLW. The type of PA model presented is probabilistic in nature, and hence reflects the current state of knowledge about the site by using probability distributions to capture what is expected (central tendency or average) and the uncertainty (e.g., standard deviation) associated with input parameters, and propagating through the model to arrive at output distributions that reflect expected performance and the overall uncertainty in the system. Estimates of contaminant release rates, concentrations in environmental media, and resulting doses to human receptors well into the future are made by running the model in Monte Carlo fashion, with each realization representing a possible combination of input parameter values. Statistical summaries of the results can be compared to regulatory performance objectives, and decision makers are better informed of the inherently uncertain aspects of the model which supports their decision-making. While this information may make some regulators uncomfortable, they must realize that uncertainties which were hidden in a deterministic analysis are revealed in a probabilistic analysis, and the chance of making a correct decision is now known rather than hoped for. The model includes many typical features and processes that would be part of a PA, but is entirely fictitious. This does not represent any particular site and is meant to be a generic example. A

  9. Key demands and characteristics of occupations performed by individuals with spinal cord injury living in Switzerland.

    Science.gov (United States)

    Nützi, M; Trezzini, B; Ronca, E; Schwegler, U

    2017-08-08

    Descriptive qualitative and quantitative study using cross-sectional data from the Swiss Spinal Cord Injury Cohort Study (SwiSCI). To determine the key demands and characteristics of occupations performed by individuals with spinal cord injury (SCI). Swiss community. Job titles indicated by SwiSCI participants were linked to occupational titles from the Occupational Information Network (O*NET) and then frequency-analyzed across sociodemographic and injury-related factors. Subsequently, average O*NET relevance values ranging from 0 to 100 were calculated for the occupations' demands and characteristics, both in general and stratified by injury-related factors. The 1549 study participants indicated a total of 717 job titles and were primarily employed in administrative and management occupations (22.1% and 16.4%, respectively). The participants' occupations predominantly required verbal abilities (average relevance [AR]=68.4) and complex problem solving skills (AR=55.8) and were characterized by conventional work tasks (AR=62.9) and social relationships (AR=58.6). Both the occupations' frequency distribution as well as the average relevance levels of their demands and characteristics differed by SCI severity. Individuals with SCI perform a broad range of occupations that are mainly characterized by cognitive and communicative demands, while physical demands are of minor importance. By informing the development of job matching profiles for vocational guidance, our study facilitates the determination of well-matching jobs for persons with SCI and may contribute to a more sustainable return to work of the affected persons.Spinal Cord advance online publication, 8 August 2017; doi:10.1038/sc.2017.84.

  10. Performance assessment modeling of pyrometallurgical process wasteforms

    International Nuclear Information System (INIS)

    Nutt, W.M.; Hill, R.N.; Bullen, D.B.

    1995-01-01

    Performance assessment analyses have been completed to estimate the behavior of high-level nuclear wasteforms generated from the pyrometallurgical processing of liquid metal reactor (LMR) and light water reactor (LWR) spent nuclear fuel. Waste emplaced in the proposed repository at Yucca Mountain is investigated as the basis for the study. The resulting cumulative actinide and fission product releases to the accessible environment within a 100,000 year period from the various pyrometallurgical process wasteforms are compared to those of directly disposed LWR spent fuel using the same total repository system model. The impact of differing radionuclide transport models on the overall release characteristics is investigated

  11. Some useful characteristics of performance models

    International Nuclear Information System (INIS)

    Worledge, D.H.

    1985-01-01

    This paper examines the demands placed upon models of human cognitive decision processes in application to Probabilistic Risk Assessment. Successful models, for this purpose, should, 1) be based on proven or plausible psychological knowledge, e.g., Rasmussen's mental schematic, 2) incorporate opportunities for slips, 3) take account of the recursive nature, in time, of corrections to mistaken actions, and 4) depend on the crew's predominant mental states that accompany such recursions. The latter is equivalent to an explicit coupling between input and output of Rasmussen's mental schematic. A family of such models is proposed with observable rate processes mediating the (conscious) mental states involved. It is expected that the cumulative probability distributions corresponding to the individual rate processes can be identified with probability-time correlations of the HCR Human Cognitive Reliability type discussed elsewhere in this session. The functional forms of the conditional rates are intuitively shown to have simple characteristics that lead to a strongly recursive stochastic process with significant predictive capability. Models of the type proposed have few parts and form a representation that is intentionally far short of a fully transparent exposition of the mental process in order to avoid making impossible demands on data

  12. Relationship between physical performance and self-reported function in healthy individuals across the lifespan.

    Science.gov (United States)

    Baldwin, Jennifer N; McKay, Marnee J; Hiller, Claire E; Moloney, Niamh; Nightingale, Elizabeth J; Burns, Joshua

    2017-08-01

    Functional outcome measures in clinical trials of musculoskeletal conditions need to be meaningful to individuals. To investigate the relationship between physical performance and self/proxy-reported function in 1000 healthy children and adults. Cross-sectional observational study (1000 Norms Project). One thousand males and females aged 3-101 years, healthy by self-report and without major physical disability, were recruited. Twelve performance-based tests were analysed: vertical and long jump, two hand dexterity tests, four balance tests, stepping reaction time, 30-second chair stand, timed up-and-down stairs, and six-minute walk. Self/proxy-reported function was assessed using the Infant-Toddler Quality of Life questionnaire, Child Health Questionnaire, Assessment of Quality of Life (AQoL)-6D Adolescent, AQoL-8D, International Physical Activity Questionnaire and work ability question. Bivariate and multivariate correlational analyses were constructed for infants (3-4y), children (5-10y), adolescents (11-17y), adults (18-59y) and older adults (60+). Socio-demographic characteristics were similar to the Australian population. Among infants/children, greater jump and sit-to-stand performance correlated with higher proxy-reported function (p  0.05). Greater jump, dexterity, balance, reaction time, sit-to-stand, stair-climbing and six-minute walk performance correlated with higher self-reported function in adults (r = -0.097 to.231; p physical measures which could form the basis of age-appropriate functional scales for clinical trials of musculoskeletal conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. General intelligence in another primate: individual differences across cognitive task performance in a New World monkey (Saguinus oedipus.

    Directory of Open Access Journals (Sweden)

    Konika Banerjee

    Full Text Available BACKGROUND: Individual differences in human cognitive abilities show consistently positive correlations across diverse domains, providing the basis for the trait of "general intelligence" (g. At present, little is known about the evolution of g, in part because most comparative studies focus on rodents or on differences across higher-level taxa. What is needed, therefore, are experiments targeting nonhuman primates, focusing on individual differences within a single species, using a broad battery of tasks. To this end, we administered a large battery of tasks, representing a broad range of cognitive domains, to a population of captive cotton-top tamarin monkeys (Saguinus oedipus. METHODOLOGY AND RESULTS: Using a Bayesian latent variable model, we show that the pattern of correlations among tasks is consistent with the existence of a general factor accounting for a small but significant proportion of the variance in each task (the lower bounds of 95% Bayesian credibility intervals for correlations between g and task performance all exceed 0.12. CONCLUSION: Individual differences in cognitive abilities within at least one other primate species can be characterized by a general intelligence factor, supporting the hypothesis that important aspects of human cognitive function most likely evolved from ancient neural substrates.

  14. Predictor Relationships between Values Held by Married Individuals, Resilience and Conflict Resolution Styles: A Model Suggestion

    Science.gov (United States)

    Tosun, Fatma; Dilmac, Bulent

    2015-01-01

    The aim of the present research is to reveal the predictor relationships between the values held by married individuals, resilience and conflict resolution styles. The research adopts a relational screening model that is a sub-type of the general screening model. The sample of the research consists of 375 married individuals, of which 173 are…

  15. An individual-based simulation model for mottled sculpin (Cottus bairdi) in a southern Appalachian stream

    Science.gov (United States)

    Brenda Rashleigh; Gary D. Grossman

    2005-01-01

    We describe and analyze a spatially explicit, individual-based model for the local population dynamics of mottled sculpin (Cottus bairdi). The model simulated daily growth, mortality, movement and spawning of individuals within a reach of stream. Juvenile and adult growth was based on consumption bioenergetics of benthic macroinvertebrate prey;...

  16. Video Self-Modeling as an Intervention Strategy for Individuals with Autism Spectrum Disorders

    Science.gov (United States)

    Gelbar, Nicholas W.; Anderson, Candace; McCarthy, Scott; Buggey, Tom

    2012-01-01

    Video self-modeling demonstrates promise as an intervention strategy to improve outcomes in individuals with autism spectrum disorders. This article summarizes the empirical evidence supporting the use of video self-modeling with individuals with autism spectrum disorders to increase language and communication, increase social skills, modify…

  17. Model description and evaluation of model performance: DOSDIM model

    International Nuclear Information System (INIS)

    Lewyckyj, N.; Zeevaert, T.

    1996-01-01

    DOSDIM was developed to assess the impact to man from routine and accidental atmospheric releases. It is a compartmental, deterministic, radiological model. For an accidental release, dynamic transfer are used in opposition to a routine release for which equilibrium transfer factors are used. Parameters values were chosen to be conservative. Transfer between compartments are described by first-order differential equations. 2 figs

  18. Modelling and evaluation of surgical performance using hidden Markov models.

    Science.gov (United States)

    Megali, Giuseppe; Sinigaglia, Stefano; Tonet, Oliver; Dario, Paolo

    2006-10-01

    Minimally invasive surgery has become very widespread in the last ten years. Since surgeons experience difficulties in learning and mastering minimally invasive techniques, the development of training methods is of great importance. While the introduction of virtual reality-based simulators has introduced a new paradigm in surgical training, skill evaluation methods are far from being objective. This paper proposes a method for defining a model of surgical expertise and an objective metric to evaluate performance in laparoscopic surgery. Our approach is based on the processing of kinematic data describing movements of surgical instruments. We use hidden Markov model theory to define an expert model that describes expert surgical gesture. The model is trained on kinematic data related to exercises performed on a surgical simulator by experienced surgeons. Subsequently, we use this expert model as a reference model in the definition of an objective metric to evaluate performance of surgeons with different abilities. Preliminary results show that, using different topologies for the expert model, the method can be efficiently used both for the discrimination between experienced and novice surgeons, and for the quantitative assessment of surgical ability.

  19. Hybrid Modeling Improves Health and Performance Monitoring

    Science.gov (United States)

    2007-01-01

    Scientific Monitoring Inc. was awarded a Phase I Small Business Innovation Research (SBIR) project by NASA's Dryden Flight Research Center to create a new, simplified health-monitoring approach for flight vehicles and flight equipment. The project developed a hybrid physical model concept that provided a structured approach to simplifying complex design models for use in health monitoring, allowing the output or performance of the equipment to be compared to what the design models predicted, so that deterioration or impending failure could be detected before there would be an impact on the equipment's operational capability. Based on the original modeling technology, Scientific Monitoring released I-Trend, a commercial health- and performance-monitoring software product named for its intelligent trending, diagnostics, and prognostics capabilities, as part of the company's complete ICEMS (Intelligent Condition-based Equipment Management System) suite of monitoring and advanced alerting software. I-Trend uses the hybrid physical model to better characterize the nature of health or performance alarms that result in "no fault found" false alarms. Additionally, the use of physical principles helps I-Trend identify problems sooner. I-Trend technology is currently in use in several commercial aviation programs, and the U.S. Air Force recently tapped Scientific Monitoring to develop next-generation engine health-management software for monitoring its fleet of jet engines. Scientific Monitoring has continued the original NASA work, this time under a Phase III SBIR contract with a joint NASA-Pratt & Whitney aviation security program on propulsion-controlled aircraft under missile-damaged aircraft conditions.

  20. A Note on the Use of Mixture Models for Individual Prediction.

    Science.gov (United States)

    Cole, Veronica T; Bauer, Daniel J

    Mixture models capture heterogeneity in data by decomposing the population into latent subgroups, each of which is governed by its own subgroup-specific set of parameters. Despite the flexibility and widespread use of these models, most applications have focused solely on making inferences for whole or sub-populations, rather than individual cases. The current article presents a general framework for computing marginal and conditional predicted values for individuals using mixture model results. These predicted values can be used to characterize covariate effects, examine the fit of the model for specific individuals, or forecast future observations from previous ones. Two empirical examples are provided to demonstrate the usefulness of individual predicted values in applications of mixture models. The first example examines the relative timing of initiation of substance use using a multiple event process survival mixture model whereas the second example evaluates changes in depressive symptoms over adolescence using a growth mixture model.

  1. Proficient brain for optimal performance: the MAP model perspective.

    Science.gov (United States)

    Bertollo, Maurizio; di Fronso, Selenia; Filho, Edson; Conforto, Silvia; Schmid, Maurizio; Bortoli, Laura; Comani, Silvia; Robazza, Claudio

    2016-01-01

    Background. The main goal of the present study was to explore theta and alpha event-related desynchronization/synchronization (ERD/ERS) activity during shooting performance. We adopted the idiosyncratic framework of the multi-action plan (MAP) model to investigate different processing modes underpinning four types of performance. In particular, we were interested in examining the neural activity associated with optimal-automated (Type 1) and optimal-controlled (Type 2) performances. Methods. Ten elite shooters (6 male and 4 female) with extensive international experience participated in the study. ERD/ERS analysis was used to investigate cortical dynamics during performance. A 4 × 3 (performance types × time) repeated measures analysis of variance was performed to test the differences among the four types of performance during the three seconds preceding the shots for theta, low alpha, and high alpha frequency bands. The dependent variables were the ERD/ERS percentages in each frequency band (i.e., theta, low alpha, high alpha) for each electrode site across the scalp. This analysis was conducted on 120 shots for each participant in three different frequency bands and the individual data were then averaged. Results. We found ERS to be mainly associated with optimal-automatic performance, in agreement with the "neural efficiency hypothesis." We also observed more ERD as related to optimal-controlled performance in conditions of "neural adaptability" and proficient use of cortical resources. Discussion. These findings are congruent with the MAP conceptualization of four performance states, in which unique psychophysiological states underlie distinct performance-related experiences. From an applied point of view, our findings suggest that the MAP model can be used as a framework to develop performance enhancement strategies based on cognitive and neurofeedback techniques.

  2. Proficient brain for optimal performance: the MAP model perspective

    Directory of Open Access Journals (Sweden)

    Maurizio Bertollo

    2016-05-01

    Full Text Available Background. The main goal of the present study was to explore theta and alpha event-related desynchronization/synchronization (ERD/ERS activity during shooting performance. We adopted the idiosyncratic framework of the multi-action plan (MAP model to investigate different processing modes underpinning four types of performance. In particular, we were interested in examining the neural activity associated with optimal-automated (Type 1 and optimal-controlled (Type 2 performances. Methods. Ten elite shooters (6 male and 4 female with extensive international experience participated in the study. ERD/ERS analysis was used to investigate cortical dynamics during performance. A 4 × 3 (performance types × time repeated measures analysis of variance was performed to test the differences among the four types of performance during the three seconds preceding the shots for theta, low alpha, and high alpha frequency bands. The dependent variables were the ERD/ERS percentages in each frequency band (i.e., theta, low alpha, high alpha for each electrode site across the scalp. This analysis was conducted on 120 shots for each participant in three different frequency bands and the individual data were then averaged. Results. We found ERS to be mainly associated with optimal-automatic performance, in agreement with the “neural efficiency hypothesis.” We also observed more ERD as related to optimal-controlled performance in conditions of “neural adaptability” and proficient use of cortical resources. Discussion. These findings are congruent with the MAP conceptualization of four performance states, in which unique psychophysiological states underlie distinct performance-related experiences. From an applied point of view, our findings suggest that the MAP model can be used as a framework to develop performance enhancement strategies based on cognitive and neurofeedback techniques.

  3. A scoring model for predicting advanced colorectal neoplasia in a screened population of asymptomatic Japanese individuals.

    Science.gov (United States)

    Sekiguchi, Masau; Kakugawa, Yasuo; Matsumoto, Minori; Matsuda, Takahisa

    2018-01-22

    Risk stratification of screened populations could help improve colorectal cancer (CRC) screening. Use of the modified Asia-Pacific Colorectal Screening (APCS) score has been proposed in the Asia-Pacific region. This study was performed to build a new useful scoring model for CRC screening. Data were reviewed from 5218 asymptomatic Japanese individuals who underwent their first screening colonoscopy. Multivariate logistic regression was used to investigate risk factors for advanced colorectal neoplasia (ACN), and a new scoring model for the prediction of ACN was developed based on the results. The discriminatory capability of the new model and the modified APCS score were assessed and compared. Internal validation was also performed. ACN was detected in 225 participants. An 8-point scoring model for the prediction of ACN was developed using five independent risk factors for ACN (male sex, higher age, presence of two or more first-degree relatives with CRC, body mass index of > 22.5 kg/m 2 , and smoking history of > 18.5 pack-years). The prevalence of ACN was 1.6% (34/2172), 5.3% (127/2419), and 10.2% (64/627) in participants with scores of statistic of the scoring model was 0.70 (95% confidence interval, 0.67-0.73) in both the development and internal validation sets, and this value was higher than that of the modified APCS score [0.68 (95% confidence interval, 0.65-0.71), P = 0.03]. We built a new simple scoring model for prediction of ACN in a Japanese population that could stratify the screened population into low-, moderate-, and high-risk groups.

  4. Linear mixed-effects models to describe individual tree crown width for China-fir in Fujian Province, southeast China.

    Science.gov (United States)

    Hao, Xu; Yujun, Sun; Xinjie, Wang; Jin, Wang; Yao, Fu

    2015-01-01

    A multiple linear model was developed for individual tree crown width of Cunninghamia lanceolata (Lamb.) Hook in Fujian province, southeast China. Data were obtained from 55 sample plots of pure China-fir plantation stands. An Ordinary Linear Least Squares (OLS) regression was used to establish the crown width model. To adjust for correlations between observations from the same sample plots, we developed one level linear mixed-effects (LME) models based on the multiple linear model, which take into account the random effects of plots. The best random effects combinations for the LME models were determined by the Akaike's information criterion, the Bayesian information criterion and the -2logarithm likelihood. Heteroscedasticity was reduced by three residual variance functions: the power function, the exponential function and the constant plus power function. The spatial correlation was modeled by three correlation structures: the first-order autoregressive structure [AR(1)], a combination of first-order autoregressive and moving average structures [ARMA(1,1)], and the compound symmetry structure (CS). Then, the LME model was compared to the multiple linear model using the absolute mean residual (AMR), the root mean square error (RMSE), and the adjusted coefficient of determination (adj-R2). For individual tree crown width models, the one level LME model showed the best performance. An independent dataset was used to test the performance of the models and to demonstrate the advantage of calibrating LME models.

  5. Peer-based control in self-managing teams: linking rational and normative influence with individual and group performance.

    Science.gov (United States)

    Stewart, Greg L; Courtright, Stephen H; Barrick, Murray R

    2012-03-01

    The authors use a multilevel framework to introduce peer-based control as a motivational state that emerges in self-managing teams. The authors specifically describe how peer-based rational control, which is defined as team members perceiving the distribution of economic rewards as dependent on input from teammates, extends and interacts with the more commonly studied normative control force of group cohesion to explain both individual and collective performance in teams. On the basis of data from 587 factory workers in 45 self-managing teams at 3 organizations, peer-based rational control corresponded with higher performance for both individuals and collective teams. Results further demonstrated that the rational and normative mechanism of peer-based control interacted to explain performance at both the individual and team levels. Increased peer-based rational control corresponded with higher individual and collective performance in teams with low cohesion, but the positive effects on performance were attenuated in cohesive teams.

  6. Staying on the job: The relationship between work performance and cognition in individuals diagnosed with multiple sclerosis.

    Science.gov (United States)

    Baughman, Brandon C; Basso, Michael R; Sinclair, Robert R; Combs, Dennis R; Roper, Brad L

    2015-01-01

    People with multiple sclerosis (MS) are apt to become unemployed as the disease progresses, and most research implies that this is due to diminishing mobility. Some studies have shown that presence of cognitive impairment also predicts employment status. Yet, no studies have examined how neuropsychological factors predict vocational performance among individuals with MS who remain employed. We assessed employer- and self-rated work performance, mobility status, and neuropsychological function in a sample of 44 individuals diagnosed with MS. Results suggest that cognitive impairment is common in these employed individuals, despite largely intact mobility status. Moreover, a significant interaction emerged, such that cognitively impaired individuals' work performance was rated more poorly by supervisors. In contrast, self-ratings of work performance were higher in cognitively impaired than in unimpaired participants. These novel findings suggest that cognitive impairment may influence work performance, even in patients whose physical disability status is relatively intact.

  7. Multilevel Modeling of the Performance Variance

    Directory of Open Access Journals (Sweden)

    Alexandre Teixeira Dias

    2012-12-01

    Full Text Available Focusing on the identification of the role played by Industry on the relations between Corporate Strategic Factors and Performance, the hierarchical multilevel modeling method was adopted when measuring and analyzing the relations between the variables that comprise each level of analysis. The adequacy of the multilevel perspective to the study of the proposed relations was identified and the relative importance analysis point out to the lower relevance of industry as a moderator of the effects of corporate strategic factors on performance, when the latter was measured by means of return on assets, and that industry don‟t moderates the relations between corporate strategic factors and Tobin‟s Q. The main conclusions of the research are that the organizations choices in terms of corporate strategy presents a considerable influence and plays a key role on the determination of performance level, but that industry should be considered when analyzing the performance variation despite its role as a moderator or not of the relations between corporate strategic factors and performance.

  8. Individual differences in airline captains' personalities, communication strategies, and crew performance

    Science.gov (United States)

    Orasanu, Judith

    1991-01-01

    Aircrew effectiveness in coping with emergencies has been linked to captain's personality profile. The present study analyzed cockpit communication during simulated flight to examine the relation between captains' discourse strategies, personality profiles, and crew performance. Positive Instrumental/Expressive captains and Instrumental-Negative captains used very similar communication strategies and their crews made few errors. Their talk was distinguished by high levels of planning and strategizing, gathering information, predicting/alerting, and explaining, especially during the emergency flight phase. Negative-Expressive captains talked less overall, and engaged in little problem solving talk, even during emergencies. Their crews made many errors. Findings support the theory that high crew performance results when captains use language to build shared mental models for problem situations.

  9. A false sense of security: safety behaviors erode objective speech performance in individuals with social anxiety disorder.

    Science.gov (United States)

    Rowa, Karen; Paulitzki, Jeffrey R; Ierullo, Maria D; Chiang, Brenda; Antony, Martin M; McCabe, Randi E; Moscovitch, David A

    2015-05-01

    In the current study, 55 participants with a diagnosis of generalized social anxiety disorder (SAD), 23 participants with a diagnosis of an anxiety disorder other than SAD with no comorbid SAD, and 50 healthy controls completed a speech task as well as self-reported measures of safety behavior use. Speeches were videotaped and coded for global and specific indicators of performance by two raters who were blind to participants' diagnostic status. Results suggested that the objective performance of people with SAD was poorer than that of both control groups, who did not differ from each other. Moreover, self-reported use of safety behaviors during the speech strongly mediated the relationship between diagnostic group and observers' performance ratings. These results are consistent with contemporary cognitive-behavioral and interpersonal models of SAD and suggest that socially anxious individuals' performance skills may be undermined by the use of safety behaviors. These data provide further support for recommendations from previous studies that the elimination of safety behaviors ought to be a priority in cognitive behavioral therapy for SAD. Copyright © 2014. Published by Elsevier Ltd.

  10. Modelling fuel cell performance using artificial intelligence

    Science.gov (United States)

    Ogaji, S. O. T.; Singh, R.; Pilidis, P.; Diacakis, M.

    Over the last few years, fuel cell technology has been increasing promisingly its share in the generation of stationary power. Numerous pilot projects are operating worldwide, continuously increasing the amount of operating hours either as stand-alone devices or as part of gas turbine combined cycles. An essential tool for the adequate and dynamic analysis of such systems is a software model that enables the user to assess a large number of alternative options in the least possible time. On the other hand, the sphere of application of artificial neural networks has widened covering such endeavours of life such as medicine, finance and unsurprisingly engineering (diagnostics of faults in machines). Artificial neural networks have been described as diagrammatic representation of a mathematical equation that receives values (inputs) and gives out results (outputs). Artificial neural networks systems have the capacity to recognise and associate patterns and because of their inherent design features, they can be applied to linear and non-linear problem domains. In this paper, the performance of the fuel cell is modelled using artificial neural networks. The inputs to the network are variables that are critical to the performance of the fuel cell while the outputs are the result of changes in any one or all of the fuel cell design variables, on its performance. Critical parameters for the cell include the geometrical configuration as well as the operating conditions. For the neural network, various network design parameters such as the network size, training algorithm, activation functions and their causes on the effectiveness of the performance modelling are discussed. Results from the analysis as well as the limitations of the approach are presented and discussed.

  11. Modelling fuel cell performance using artificial intelligence

    Energy Technology Data Exchange (ETDEWEB)

    Ogaji, S.O.T.; Singh, R.; Pilidis, P.; Diacakis, M. [Power Propulsion and Aerospace Engineering Department, Centre for Diagnostics and Life Cycle Costs, Cranfield University (United Kingdom)

    2006-03-09

    Over the last few years, fuel cell technology has been increasing promisingly its share in the generation of stationary power. Numerous pilot projects are operating worldwide, continuously increasing the amount of operating hours either as stand-alone devices or as part of gas turbine combined cycles. An essential tool for the adequate and dynamic analysis of such systems is a software model that enables the user to assess a large number of alternative options in the least possible time. On the other hand, the sphere of application of artificial neural networks has widened covering such endeavours of life such as medicine, finance and unsurprisingly engineering (diagnostics of faults in machines). Artificial neural networks have been described as diagrammatic representation of a mathematical equation that receives values (inputs) and gives out results (outputs). Artificial neural networks systems have the capacity to recognise and associate patterns and because of their inherent design features, they can be applied to linear and non-linear problem domains. In this paper, the performance of the fuel cell is modelled using artificial neural networks. The inputs to the network are variables that are critical to the performance of the fuel cell while the outputs are the result of changes in any one or all of the fuel cell design variables, on its performance. Critical parameters for the cell include the geometrical configuration as well as the operating conditions. For the neural network, various network design parameters such as the network size, training algorithm, activation functions and their causes on the effectiveness of the performance modelling are discussed. Results from the analysis as well as the limitations of the approach are presented and discussed. (author)

  12. Correlations among measures of knee stiffness, gait performance and complaints in individuals with knee osteoarthritis.

    Science.gov (United States)

    Oatis, Carol A; Wolff, Edward F; Lockard, Margery A; Michener, Lori A; Robbins, Steven J

    2013-03-01

    Stiffness is a common complaint in individuals with knee osteoarthritis and is a component of the osteoarthritis diagnosis. Yet the relationship between stiffness and function is poorly understood and methods to quantify stiffness are limited. Using a cross-sectional observational design with 66 subjects with knee osteoarthritis, stiffness and damping coefficients were calculated from a relaxed knee oscillation procedure. Gait parameters were measured using an electronic walkway. Self-reported pain, stiffness, and function were measured with the Western Ontario and McMaster Osteoarthritis Index. Correlation and Alexander's normalized-t approximation analyses were used to assess associations among the variables. Subset analysis was performed on subjects with and without tibiofemoral joint crepitus. Slight to moderate correlations existed between stiffness and damping coefficients and most gait parameters ((| r |=0.30-0.56; PMcMaster Osteoarthritis Index scores and all gait parameters (| r |=0.35-0.62; Pcoefficient was only slightly associated with patient-rated Western Ontario and McMaster Osteoarthritis Index stiffness subscale scores. Subset analysis revealed significant correlations that differed between those with and without crepitus. These findings suggest that laboratory measured stiffness and damping coefficients, Western Ontario and McMaster Osteoarthritis Index scores and gait-related measurements assess different aspects related to movement in individuals with knee osteoarthritis. Stiffness and damping coefficients may offer the ability to explain gait changes in the knee that are independent of a person's perceptions particularly in the early stages of the disease. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. CONCEPTUAL APRROACH OF LEADERSHIP AND EMPLOYEES’ INDIVIDUAL PERFORMANCE RELATIONSHIP

    Directory of Open Access Journals (Sweden)

    Ispas Andreia

    2012-07-01

    Full Text Available There is a need for more leadership research in the hotel industry. A reason is the better understanding of the effects and influences that manager-employee relationship can have. Further, this can improve employee performance at their work and clients would be more satisfied. Due to the emergent stage of this field of research, the leadership and employee performance relationship has a lot of potential for being investigated in the context of hotel industry. There are many types of leadership styles recommended to be used in managers’ daily hotels’ activities. The most suggested is transformational leadership. Hotel industry is part of hospitality industry and is providing different services such as accommodation, food nbeverage, entertainment. This makes hotel industry very specific and the hotel products, services unique for each of client. That’s why high standards of organizational performance, a good manager-employee relationship and a high perceived employee performance by the clients are the keys for a long and sustainable business. Leadership is important in getting people to do the right things at their job. More, it helps employee to work better, to be motivated, to strive for excellence and perform beyond expectations. The first objective of this paper is to analyze the main approaches of leadership styles applied in the context of hotel industry studies. The second objective is to explore, from a theoretical point of view, the direct and indirect relationship between leadership style and employee performance based on two mediator factors: job satisfaction and organizational commitment. These two mediators are the most used in organizational researches and have a high degree of validity. The methodology applied is based on documentary study review and critic analysis of the concepts used by the literature. The results of the conceptual paper are: the construction of the conceptual model of scientific research

  14. Modelling the predictive performance of credit scoring

    Directory of Open Access Journals (Sweden)

    Shi-Wei Shen

    2013-07-01

    Research purpose: The purpose of this empirical paper was to examine the predictive performance of credit scoring systems in Taiwan. Motivation for the study: Corporate lending remains a major business line for financial institutions. However, in light of the recent global financial crises, it has become extremely important for financial institutions to implement rigorous means of assessing clients seeking access to credit facilities. Research design, approach and method: Using a data sample of 10 349 observations drawn between 1992 and 2010, logistic regression models were utilised to examine the predictive performance of credit scoring systems. Main findings: A test of Goodness of fit demonstrated that credit scoring models that incorporated the Taiwan Corporate Credit Risk Index (TCRI, micro- and also macroeconomic variables possessed greater predictive power. This suggests that macroeconomic variables do have explanatory power for default credit risk. Practical/managerial implications: The originality in the study was that three models were developed to predict corporate firms’ defaults based on different microeconomic and macroeconomic factors such as the TCRI, asset growth rates, stock index and gross domestic product. Contribution/value-add: The study utilises different goodness of fits and receiver operator characteristics during the examination of the robustness of the predictive power of these factors.

  15. Removal of Negative Feedback Enhances WCST Performance for Individuals with ASD

    Science.gov (United States)

    Broadbent, Jaclyn; Stokes, Mark A.

    2013-01-01

    Negative feedback was explored as a potential mechanism that may exacerbate perseverative behaviours in individuals with Asperger's syndrome (AS). The current study compared 50 individuals with AS and 50 typically developing (TD) individuals for their abilities to successfully complete the Wisconsin Card Sorting Task (WCST) in the presence or…

  16. ASD Is Not DLI: Individuals With Autism and Individuals With Syntactic DLI Show Similar Performance Level in Syntactic Tasks, but Different Error Patterns.

    Science.gov (United States)

    Sukenik, Nufar; Friedmann, Naama

    2018-01-01

    Do individuals with autism have a developmental syntactic impairment, DLI (formerly known as SLI)? In this study we directly compared the performance of 18 individuals with Autism Spectrum Disorder (ASD) aged 9;0-18;0 years with that of 93 individuals with Syntactic-Developmental Language Impairment (SyDLI) aged 8;8-14;6 (and with 166 typically-developing children aged 5;2-18;1). We tested them using three syntactic tests assessing the comprehension and production of syntactic structures that are known to be sensitive to syntactic impairment: elicitation of subject and object relative clauses, reading and paraphrasing of object relatives, and repetition of complex syntactic structures including Wh questions, relative clauses, topicalized sentences, sentences with verb movement, sentences with A-movement, and embedded sentences. The results were consistent across the three tasks: the overall rate of correct performance on the syntactic tasks is similar for the children with ASD and those with SyDLI. However, once we look closer, they are very different. The types of errors of the ASD group differ from those of the SyDLI group-the children with ASD provide various types of pragmatically infelicitous responses that are not evinced in the SyDLI or in the age equivalent typically-developing groups. The two groups (ASD and SyDLI) also differ in the pattern of performance-the children with SyDLI show a syntactically-principled pattern of impairment, with selective difficulty in specific sentence types (such as sentences derived by movement of the object across the subject), and normal performance on other structures (such as simple sentences). In contrast, the ASD participants showed generalized low performance on the various sentence structures. Syntactic performance was far from consistent within the ASD group. Whereas all ASD participants had errors that can originate in pragmatic/discourse difficulties, seven of them had completely normal syntax in the structures we

  17. WWER reactor fuel performance, modelling and experimental support. Proceedings

    International Nuclear Information System (INIS)

    Stefanova, S.; Chantoin, P.; Kolev, I.

    1994-01-01

    This publication is a compilation of 36 papers presented at the International Seminar on WWER Reactor Fuel Performance, Modelling and Experimental Support, organised by the Institute for Nuclear Research and Nuclear Energy (BG), in cooperation with the International Atomic Energy Agency. The Seminar was attended by 76 participants from 16 countries, including representatives of all major Russian plants and institutions responsible for WWER reactor fuel manufacturing, design and research. The reports are grouped in four chapters: 1) WWER Fuel Performance and Economics: Status and Improvement Prospects: 2) WWER Fuel Behaviour Modelling and Experimental Support; 3) Licensing of WWER Fuel and Fuel Analysis Codes; 4) Spent Fuel of WWER Plants. The reports from the corresponding four panel discussion sessions are also included. All individual papers are recorded in INIS as separate items

  18. WWER reactor fuel performance, modelling and experimental support. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Stefanova, S; Chantoin, P; Kolev, I [eds.

    1994-12-31

    This publication is a compilation of 36 papers presented at the International Seminar on WWER Reactor Fuel Performance, Modelling and Experimental Support, organised by the Institute for Nuclear Research and Nuclear Energy (BG), in cooperation with the International Atomic Energy Agency. The Seminar was attended by 76 participants from 16 countries, including representatives of all major Russian plants and institutions responsible for WWER reactor fuel manufacturing, design and research. The reports are grouped in four chapters: (1) WWER Fuel Performance and Economics: Status and Improvement Prospects: (2) WWER Fuel Behaviour Modelling and Experimental Support; (3) Licensing of WWER Fuel and Fuel Analysis Codes; (4) Spent Fuel of WWER Plants. The reports from the corresponding four panel discussion sessions are also included. All individual papers are recorded in INIS as separate items.

  19. Modelling Individual Evacuation Decisions during Natural Disasters: A Case Study of Volcanic Crisis in Merapi, Indonesia

    Directory of Open Access Journals (Sweden)

    Jumadi

    2018-05-01

    Full Text Available As the size of human populations increases, so does the severity of the impacts of natural disasters. This is partly because more people are now occupying areas which are susceptible to hazardous natural events, hence, evacuation is needed when such events occur. Evacuation can be the most important action to minimise the impact of any disaster, but in many cases there are always people who are reluctant to leave. This paper describes an agent-based model (ABM of evacuation decisions, focusing on the emergence of reluctant people in times of crisis and using Merapi, Indonesia as a case study. The individual evacuation decision model is influenced by several factors formulated from a literature review and survey. We categorised the factors influencing evacuation decisions into two opposing forces, namely, the driving factors to leave (evacuate versus those to stay, to formulate the model. The evacuation decision (to stay/leave of an agent is based on an evaluation of the strength of these driving factors using threshold-based rules. This ABM was utilised with a synthetic population from census microdata, in which everyone is characterised by the decision rule. Three scenarios with varying parameters are examined to calibrate the model. Validations were conducted using a retrodictive approach by performing spatial and temporal comparisons between the outputs of simulation and the real data. We present the results of the simulations and discuss the outcomes to conclude with the most plausible scenario.

  20. Individual taper models for natural cedar and Taurus fir mixed stands of Bucak Region, Turkey

    Directory of Open Access Journals (Sweden)

    Ramazan Özçelik

    2017-11-01

    Full Text Available In this study, we assessed the performance of different types of taper equations for predicting tree diameters at specific heights and total stem volumes for mixed stands of Taurus cedar (Cedrus libani A. Rich. and Taurus fir (Abies cilicica Carr.. We used data from mixed stands containing a total of 131 cedar and 124 Taurus fir trees. We evaluated six commonly used and well-known forestry taper functions developed by a variety of researchers (Biging (1984, Zakrzewski (1999, Muhairwe (1999, Fang et al. (2000, Kozak (2004, and Sharma and Zhang (2004. To address problems related to autocorrelation and multicollinearity in the hierarchical data associated with the construction of taper models, we used appropriate statistical procedures for the model fitting. We compared model performances based on the analysis of three goodness-of-fit statistics and found the compatible segmented model of Fang et al. (2000 to be superior in describing the stem profile and stem volume of both tree species in mixed stands. The equation used by Zakrzewski (1999 exhibited the poorest fitting results of the three taper equations. In general, we found segmented taper equations to provide more accurate predictions than variable-form models for both tree species. Results from the non-linear extra sum of squares method indicate that stem tapers differ among tree species in mixed stands. Therefore, a different taper function should be used for each tree species in mixed stands in the Bucak district. Using individual-specific taper equations yields more robust estimations and, therefore, will enhance the prediction accuracy of diameters at different heights and volumes in mixed stands.

  1. Childhood conditions and current physical performance among non-institutionalized individuals aged 50+ in Israel.

    Science.gov (United States)

    Weinstein, Galit

    2016-12-01

    Adverse socioeconomic conditions in childhood have been previously linked with high risk of various health conditions. However, the association with future physical function has been less studied. Hand grip strength and chair-rising time are objective measures of physical capability indicating current and future health outcomes. The aim of this study was to test the hypothesis that perceived socio-economic status in childhood is related to current measures of physical function, among Israeli participants of the Survey of Health, Ageing and Retirement in Europe project. The study included 2300 participants aged 50 years or older (mean age 68 ± 10; 56 % women). Generalized linear regression models were used to examine the associations of childhood wealth and number of books in residence with grip strength and time to complete five rises from a chair. Logistic regression models were used to assess the relationships between the early life conditions and the ability to perform the physical tests. Adjustment was made for current income or household wealth, and for demographic, anthropometric, health, and life-style measures. Being wealthy and having a large number of books at home in childhood was associated with a stronger hand grip and a better chair-rise test performance. These associations were more robust in women compared to men, and persisted after adjustment for potential covariates. In addition, childhood wealth and number of books were associated with lower risk of being unable to perform the tests. Thus, early-life programming may contribute to physical function indicators in mid- and late-life.

  2. CASTOR detector. Model, objectives and simulated performance

    International Nuclear Information System (INIS)

    Angelis, A. L. S.; Mavromanolakis, G.; Panagiotou, A. D.; Aslanoglou, X.; Nicolis, N.; Lobanov, M.; Erine, S.; Kharlov, Y. V.; Bogolyubsky, M. Y.; Kurepin, A. B.; Chileev, K.; Wlodarczyk, Z.

    2001-01-01

    It is presented a phenomenological model describing the formation and evolution of a Centauro fireball in the baryon-rich region in nucleus-nucleus interactions in the upper atmosphere and at the LHC. The small particle multiplicity and imbalance of electromagnetic and hadronic content characterizing a Centauro event and also the strongly penetrating particles (assumed to be strangelets) frequently accompanying them can be naturally explained. It is described the CASTOR calorimeter, a sub detector of the ALICE experiment dedicated to the search for Centauro in the very forward, baryon-rich region of central Pb+Pb collisions at the LHC. The basic characteristics and simulated performance of the calorimeter are presented

  3. The Relationship of Individual Difference and Group Process Variables with Self-Managed Team Performance: A Field Investigation

    National Research Council Canada - National Science Library

    Jordan, Mark

    2001-01-01

    The efficacy of dispositional individual difference team composition and group process variables in explaining team performance was examined for 1,030 military officers working in 92 teams over a 5-week period...

  4. Simulation of Drought-induced Tree Mortality Using a New Individual and Hydraulic Trait-based Model (S-TEDy)

    Science.gov (United States)

    Sinha, T.; Gangodagamage, C.; Ale, S.; Frazier, A. G.; Giambelluca, T. W.; Kumagai, T.; Nakai, T.; Sato, H.

    2017-12-01

    Drought-related tree mortality at a regional scale causes drastic shifts in carbon and water cycling in Southeast Asian tropical rainforests, where severe droughts are projected to occur more frequently, especially under El Niño conditions. To provide a useful tool for projecting the tropical rainforest dynamics under climate change conditions, we developed the Spatially Explicit Individual-Based (SEIB) Dynamic Global Vegetation Model (DGVM) applicable to simulating mechanistic tree mortality induced by the climatic impacts via individual-tree-scale ecophysiology such as hydraulic failure and carbon starvation. In this study, we present the new model, SEIB-originated Terrestrial Ecosystem Dynamics (S-TEDy) model, and the computation results were compared with observations collected at a field site in a Bornean tropical rainforest. Furthermore, after validating the model's performance, numerical experiments addressing a future of the tropical rainforest were conducted using some global climate model (GCM) simulation outputs.

  5. ASD Is Not DLI: Individuals With Autism and Individuals With Syntactic DLI Show Similar Performance Level in Syntactic Tasks, but Different Error Patterns

    Directory of Open Access Journals (Sweden)

    Nufar Sukenik

    2018-04-01

    Full Text Available Do individuals with autism have a developmental syntactic impairment, DLI (formerly known as SLI? In this study we directly compared the performance of 18 individuals with Autism Spectrum Disorder (ASD aged 9;0–18;0 years with that of 93 individuals with Syntactic-Developmental Language Impairment (SyDLI aged 8;8–14;6 (and with 166 typically-developing children aged 5;2–18;1. We tested them using three syntactic tests assessing the comprehension and production of syntactic structures that are known to be sensitive to syntactic impairment: elicitation of subject and object relative clauses, reading and paraphrasing of object relatives, and repetition of complex syntactic structures including Wh questions, relative clauses, topicalized sentences, sentences with verb movement, sentences with A-movement, and embedded sentences. The results were consistent across the three tasks: the overall rate of correct performance on the syntactic tasks is similar for the children with ASD and those with SyDLI. However, once we look closer, they are very different. The types of errors of the ASD group differ from those of the SyDLI group—the children with ASD provide various types of pragmatically infelicitous responses that are not evinced in the SyDLI or in the age equivalent typically-developing groups. The two groups (ASD and SyDLI also differ in the pattern of performance—the children with SyDLI show a syntactically-principled pattern of impairment, with selective difficulty in specific sentence types (such as sentences derived by movement of the object across the subject, and normal performance on other structures (such as simple sentences. In contrast, the ASD participants showed generalized low performance on the various sentence structures. Syntactic performance was far from consistent within the ASD group. Whereas all ASD participants had errors that can originate in pragmatic/discourse difficulties, seven of them had completely normal syntax

  6. Minimal detectable change of the Personal and Social Performance scale in individuals with schizophrenia.

    Science.gov (United States)

    Lee, Shu-Chun; Tang, Shih-Fen; Lu, Wen-Shian; Huang, Sheau-Ling; Deng, Nai-Yu; Lue, Wen-Chyn; Hsieh, Ching-Lin

    2016-12-30

    The minimal detectable change (MDC) of the Personal and Social Performance scale (PSP) has not yet been investigated, limiting its utility in data interpretation. The purpose of this study was to determine the MDCs of the PSP administered by the same rater or different raters in individuals with schizophrenia. Participants with schizophrenia were recruited from two psychiatric community rehabilitation centers to complete the PSP assessments twice, 2 weeks apart, by the same rater or 2 different raters. MDC values were calculated from the coefficients of intra- and inter-rater reliability (i.e., intraclass correlation coefficients). Forty patients (mean age 36.9 years, SD 9.7) from one center participated in the intra-rater reliability study. Another 40 patients (mean age 44.3 years, SD 11.1) from the other center participated in the inter-rater study. The MDCs (MDC%) of the PSP were 10.7 (17.1%) for the same rater and 16.2 (24.1%) for different raters. The MDCs of the PSP appeared appropriate for clinical trials aiming to determine whether a real change in social functioning has occurred in people with schizophrenia. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  7. Stepwise latent class models for explaining group-level putcomes using discrete individual-level predictors

    NARCIS (Netherlands)

    Bennink, Margot; Croon, M.A.; Vermunt, J.K.

    2015-01-01

    Explaining group-level outcomes from individual-level predictors requires aggregating the individual-level scores to the group level and correcting the group-level estimates for measurement errors in the aggregated scores. However, for discrete variables it is not clear how to perform the

  8. Assessing Individual Weather Risk-Taking and Its Role in Modeling Likelihood of Hurricane Evacuation

    Science.gov (United States)

    Stewart, A. E.

    2017-12-01

    This research focuses upon measuring an individual's level of perceived risk of different severe and extreme weather conditions using a new self-report measure, the Weather Risk-Taking Scale (WRTS). For 32 severe and extreme situations in which people could perform an unsafe behavior (e. g., remaining outside with lightning striking close by, driving over roadways covered with water, not evacuating ahead of an approaching hurricane, etc.), people rated: 1.their likelihood of performing the behavior, 2. The perceived risk of performing the behavior, 3. the expected benefits of performing the behavior, and 4. whether the behavior has actually been performed in the past. Initial development research with the measure using 246 undergraduate students examined its psychometric properties and found that it was internally consistent (Cronbach's a ranged from .87 to .93 for the four scales) and that the scales possessed good temporal (test-retest) reliability (r's ranged from .84 to .91). A second regression study involving 86 undergraduate students found that taking weather risks was associated with having taken similar risks in one's past and with the personality trait of sensation-seeking. Being more attentive to the weather and perceiving its risks when it became extreme was associated with lower likelihoods of taking weather risks (overall regression model, R2adj = 0.60). A third study involving 334 people examined the contributions of weather risk perceptions and risk-taking in modeling the self-reported likelihood of complying with a recommended evacuation ahead of a hurricane. Here, higher perceptions of hurricane risks and lower perceived benefits of risk-taking along with fear of severe weather and hurricane personal self-efficacy ratings were all statistically significant contributors to the likelihood of evacuating ahead of a hurricane. Psychological rootedness and attachment to one's home also tend to predict lack of evacuation. This research highlights the

  9. Impact of individual resilience and safety climate on safety performance and psychological stress of construction workers: A case study of the Ontario construction industry.

    Science.gov (United States)

    Chen, Yuting; McCabe, Brenda; Hyatt, Douglas

    2017-06-01

    The construction industry has hit a plateau in terms of safety performance. Safety climate is regarded as a leading indicator of safety performance; however, relatively little safety climate research has been done in the Canadian construction industry. Safety climate may be geographically sensitive, thus it is necessary to examine how the construct of safety climate is defined and used to improve safety performance in different regions. On the other hand, more and more attention has been paid to job related stress in the construction industry. Previous research proposed that individual resilience may be associated with a better safety performance and may help employees manage stress. Unfortunately, few empirical research studies have examined this hypothesis. This paper aims to examine the role of safety climate and individual resilience in safety performance and job stress in the Canadian construction industry. The research was based on 837 surveys collected in Ontario between June 2015 and June 2016. Structural equation modeling (SEM) techniques were used to explore the impact of individual resilience and safety climate on physical safety outcomes and on psychological stress among construction workers. The results show that safety climate not only affected construction workers' safety performance but also indirectly affected their psychological stress. In addition, it was found that individual resilience had a direct negative impact on psychological stress but had no impact on physical safety outcomes. These findings highlight the roles of both organizational and individual factors in individual safety performance and in psychological well-being. Construction organizations need to not only monitor employees' safety performance, but also to assess their employees' psychological well-being. Promoting a positive safety climate together with developing training programs focusing on improving employees' psychological health - especially post-trauma psychological

  10. Nonlinear joint models for individual dynamic prediction of risk of death using Hamiltonian Monte Carlo: application to metastatic prostate cancer

    Directory of Open Access Journals (Sweden)

    Solène Desmée

    2017-07-01

    Full Text Available Abstract Background Joint models of longitudinal and time-to-event data are increasingly used to perform individual dynamic prediction of a risk of event. However the difficulty to perform inference in nonlinear models and to calculate the distribution of individual parameters has long limited this approach to linear mixed-effect models for the longitudinal part. Here we use a Bayesian algorithm and a nonlinear joint model to calculate individual dynamic predictions. We apply this approach to predict the risk of death in metastatic castration-resistant prostate cancer (mCRPC patients with frequent Prostate-Specific Antigen (PSA measurements. Methods A joint model is built using a large population of 400 mCRPC patients where PSA kinetics is described by a biexponential function and the hazard function is a PSA-dependent function. Using Hamiltonian Monte Carlo algorithm implemented in Stan software and the estimated population parameters in this population as priors, the a posteriori distribution of the hazard function is computed for a new patient knowing his PSA measurements until a given landmark time. Time-dependent area under the ROC curve (AUC and Brier score are derived to assess discrimination and calibration of the model predictions, first on 200 simulated patients and then on 196 real patients that are not included to build the model. Results Satisfying coverage probabilities of Monte Carlo prediction intervals are obtained for longitudinal and hazard functions. Individual dynamic predictions provide good predictive performances for landmark times larger than 12 months and horizon time of up to 18 months for both simulated and real data. Conclusions As nonlinear joint models can characterize the kinetics of biomarkers and their link with a time-to-event, this approach could be useful to improve patient’s follow-up and the early detection of most at risk patients.

  11. A rational inference approach to group and individual-level sentence comprehension performance in aphasia.

    Science.gov (United States)

    Warren, Tessa; Dickey, Michael Walsh; Liburd, Teljer L

    2017-07-01

    The rational inference, or noisy channel, account of language comprehension predicts that comprehenders are sensitive to the probabilities of different interpretations for a given sentence and adapt as these probabilities change (Gibson, Bergen & Piantadosi, 2013). This account provides an important new perspective on aphasic sentence comprehension: aphasia may increase the likelihood of sentence distortion, leading people with aphasia (PWA) to rely more on the prior probability of an interpretation and less on the form or structure of the sentence (Gibson, Sandberg, Fedorenko, Bergen & Kiran, 2015). We report the results of a sentence-picture matching experiment that tested the predictions of the rational inference account and other current models of aphasic sentence comprehension across a variety of sentence structures. Consistent with the rational inference account, PWA showed similar sensitivity to the probability of particular kinds of form distortions as age-matched controls, yet overall their interpretations relied more on prior probability and less on sentence form. As predicted by rational inference, but not by other models of sentence comprehension in aphasia, PWA's interpretations were more faithful to the form for active and passive sentences than for direct object and prepositional object sentences. However contra rational inference, there was no evidence that individual PWA's severity of syntactic or semantic impairment predicted their sensitivity to form versus the prior probability of a sentence, as cued by semantics. These findings confirm and extend previous findings that suggest the rational inference account holds promise for explaining aphasic and neurotypical comprehension, but they also raise new challenges for the account. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. The Effect of Cerebellar Transcranial Direct Current Stimulation on A Throwing Task Depends on Individual Level of Task Performance.

    Science.gov (United States)

    Mizuguchi, Nobuaki; Katayama, Takashi; Kanosue, Kazuyuki

    2018-02-10

    The effect of cerebellar transcranial direct current stimulation (tDCS) on motor performance remains controversial. Some studies suggest that the effect of tDCS depends upon task-difficulty and individual level of task performance. Here, we investigated whether the effect of cerebellar tDCS on the motor performance depends upon the individual's level of performance. Twenty-four naïve participants practiced dart throwing while receiving a 2-mA cerebellar tDCS for 20 min under three stimulus conditions (anodal-, cathodal-, and sham-tDCS) on separate days with a double-blind, counter-balanced cross-over design. Task performance was assessed by measuring the distance between the center of the bull's eye and the dart's position. Although task performance tended to improve throughout the practice under all stimulus conditions, improvement within a given day was not significant as compared to the first no-stimulus block. In addition, improvement did not differ among stimulation conditions. However, the magnitude of improvement was associated with an individual's level of task performance only under cathodal tDCS condition (p performance improvement only for the sub-group of participants with lower performance levels as compared to that with sham-tDCS (p task performance. Thus, cerebellar tDCS would facilitate learning of a complex motor skill task only in a subset of individuals. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  13. A model to decompose the performance of supplementary private health insurance markets.

    Science.gov (United States)

    Leidl, Reiner

    2008-09-01

    For an individual insurance firm offering supplementary private health insurance, a model is developed to decompose market performance in terms of insurer profits. For the individual contract, the model specifies the conditions under which adverse selection, cream skimming, and moral hazard occur, shows the impact of information on contracting, and the profit contribution. Contracts are determined by comparing willingness to pay for insurance with the individual's risk position, and information on both sides of the market. Finally, performance is aggregated up to the total market. The model provides a framework to explain the attractiveness of supplementary markets to insurers.

  14. The Moderating Effect of Psychological Empowerment on the Relationship between Network Centrality and Individual Job Performance

    Science.gov (United States)

    2012-03-22

    analysis, KMO equaled .75, which is above the acceptable limit of 0.5 (Kaiser, 1974). The KMO values for the individual items were greater than .61...factor loadings for PE after rotation. For OCB, the overall KMO equaled .81 and the KMO for the individual items were greater than .57, both above the...after rotation. For CWB, the overall KMO equaled .75; however, one of the individual factors was less than .50 (CWB4) and had to be removed from the

  15. The COD Model: Simulating Workgroup Performance

    Science.gov (United States)

    Biggiero, Lucio; Sevi, Enrico

    Though the question of the determinants of workgroup performance is one of the most central in organization science, precise theoretical frameworks and formal demonstrations are still missing. In order to fill in this gap the COD agent-based simulation model is here presented and used to study the effects of task interdependence and bounded rationality on workgroup performance. The first relevant finding is an algorithmic demonstration of the ordering of interdependencies in terms of complexity, showing that the parallel mode is the most simplex, followed by the sequential and then by the reciprocal. This result is far from being new in organization science, but what is remarkable is that now it has the strength of an algorithmic demonstration instead of being based on the authoritativeness of some scholar or on some episodic empirical finding. The second important result is that the progressive introduction of realistic limits to agents' rationality dramatically reduces workgroup performance and addresses to a rather interesting result: when agents' rationality is severely bounded simple norms work better than complex norms. The third main finding is that when the complexity of interdependence is high, then the appropriate coordination mechanism is agents' direct and active collaboration, which means teamwork.

  16. Predicting Longitudinal Change in Language Production and Comprehension in Individuals with Down Syndrome: Hierarchical Linear Modeling.

    Science.gov (United States)

    Chapman, Robin S.; Hesketh, Linda J.; Kistler, Doris J.

    2002-01-01

    Longitudinal change in syntax comprehension and production skill, measured over six years, was modeled in 31 individuals (ages 5-20) with Down syndrome. The best fitting Hierarchical Linear Modeling model of comprehension uses age and visual and auditory short-term memory as predictors of initial status, and age for growth trajectory. (Contains…

  17. Effects of uncertainty in model predictions of individual tree volume on large area volume estimates

    Science.gov (United States)

    Ronald E. McRoberts; James A. Westfall

    2014-01-01

    Forest inventory estimates of tree volume for large areas are typically calculated by adding model predictions of volumes for individual trees. However, the uncertainty in the model predictions is generally ignored with the result that the precision of the large area volume estimates is overestimated. The primary study objective was to estimate the effects of model...

  18. Career Planning: Towards a More Inclusive Model for Women and Diverse Individuals

    Science.gov (United States)

    Banks, Claretha H.

    2006-01-01

    Since the 1953 introduction of Super's model of career development, many publications regarding career development and career planning have been developed. However, career planning models for women and diverse individuals are not prevalent. This paper contains a literature review of various well-known models that have few specific applications for…

  19. Understanding Customer Attrition at an Individual Level: a New Model in Grocery Retail Context

    OpenAIRE

    Gautrais , Clément; Cellier , Peggy; Guyet , Thomas; Quiniou , René; Termier , Alexandre

    2016-01-01

    International audience; This paper presents a new model to detect and explain customer defection in a grocery retail context. This new model analyzes the evolution of each customer basket content. It therefore provides actionable knowledge for the retailer at an individual scale. In addition, this model is able to identify customers that are likely to defect in the future months.

  20. Do comprehensive performance measurement systems help or hinder managers' mental model development?

    OpenAIRE

    Matthew Hall

    2011-01-01

    This study examines whether and how the process of updating and changing mental models (learning) helps to explain how performance measurement systems (PMS) affect individual performance. Although prior studies (e.g., Hall, 2008; Burney and Widener, 2007; Burney et al., 2009) highlight the important role of particular cognitive and motivational mechanisms, such as role clarity and organizational justice, they do not consider how PMS can improve performance by helping individuals to update the...

  1. lme4qtl: linear mixed models with flexible covariance structure for genetic studies of related individuals.

    Science.gov (United States)

    Ziyatdinov, Andrey; Vázquez-Santiago, Miquel; Brunel, Helena; Martinez-Perez, Angel; Aschard, Hugues; Soria, Jose Manuel

    2018-02-27

    Quantitative trait locus (QTL) mapping in genetic data often involves analysis of correlated observations, which need to be accounted for to avoid false association signals. This is commonly performed by modeling such correlations as random effects in linear mixed models (LMMs). The R package lme4 is a well-established tool that implements major LMM features using sparse matrix methods; however, it is not fully adapted for QTL mapping association and linkage studies. In particular, two LMM features are lacking in the base version of lme4: the definition of random effects by custom covariance matrices; and parameter constraints, which are essential in advanced QTL models. Apart from applications in linkage studies of related individuals, such functionalities are of high interest for association studies in situations where multiple covariance matrices need to be modeled, a scenario not covered by many genome-wide association study (GWAS) software. To address the aforementioned limitations, we developed a new R package lme4qtl as an extension of lme4. First, lme4qtl contributes new models for genetic studies within a single tool integrated with lme4 and its companion packages. Second, lme4qtl offers a flexible framework for scenarios with multiple levels of relatedness and becomes efficient when covariance matrices are sparse. We showed the value of our package using real family-based data in the Genetic Analysis of Idiopathic Thrombophilia 2 (GAIT2) project. Our software lme4qtl enables QTL mapping models with a versatile structure of random effects and efficient computation for sparse covariances. lme4qtl is available at https://github.com/variani/lme4qtl .

  2. Micro-macro multilevel latent class models with multiple discrete individual-level variables

    NARCIS (Netherlands)

    Bennink, M.; Croon, M.A.; Kroon, B.; Vermunt, J.K.

    2016-01-01

    An existing micro-macro method for a single individual-level variable is extended to the multivariate situation by presenting two multilevel latent class models in which multiple discrete individual-level variables are used to explain a group-level outcome. As in the univariate case, the

  3. Additive gamma frailty models with applications to competing risks in related individuals

    DEFF Research Database (Denmark)

    Eriksson, Frank; Scheike, Thomas

    2015-01-01

    Epidemiological studies of related individuals are often complicated by the fact that follow-up on the event type of interest is incomplete due to the occurrence of other events. We suggest a class of frailty models with cause-specific hazards for correlated competing events in related individual...

  4. Analysis of habitat-selection rules using an individual-based model

    Science.gov (United States)

    Steven F. Railsback; Bret C. Harvey

    2002-01-01

    Abstract - Despite their promise for simulating natural complexity,individual-based models (IBMs) are rarely used for ecological research or resource management. Few IBMs have been shown to reproduce realistic patterns of behavior by individual organisms.To test our IBM of stream salmonids and draw conclusions about foraging theory,we analyzed the IBM ’s ability to...

  5. Functional form comparison between the population and the individual Poisson based TCP models

    International Nuclear Information System (INIS)

    Schinkel, C.; Stavreva, N.; Stavrev, P.; Carlone, M.; Fallone, B.G.

    2007-01-01

    In this work, the functional form similarity between the individual and fundamental population TCP models is investigated. Using the fact that both models can be expressed in terms of the geometric parameters γ 50 and D 50 , we show that they have almost identical functional form for values of γ 50 ≥1. The conceptual inadequacy of applying an individual model to clinical data is also discussed. A general individual response TCP expression is given, parameterized by D f and γ f - the dose corresponding to a control level of f, and the normalized slope at that point. It is shown that the dose-response may be interpreted as an individual response only if γ 50 is sufficiently high. Based on the functional form equivalency between the individual and the population TCP models, we discuss the possibility of applying the individual TCP model for the case of heterogeneous irradiations. Due to the fact that the fundamental population TCP model is derived for homogeneous irradiations only, we propose the use of the EUD, given by the generalized mean dose, when the fundamental population TCP model is used to fit clinical data. (author)

  6. Discovering the Power of Individual-Based Modelling in Teaching and Learning: The Study of a Predator-Prey System

    Science.gov (United States)

    Ginovart, Marta

    2014-08-01

    The general aim is to promote the use of individual-based models (biological agent-based models) in teaching and learning contexts in life sciences and to make their progressive incorporation into academic curricula easier, complementing other existing modelling strategies more frequently used in the classroom. Modelling activities for the study of a predator-prey system for a mathematics classroom in the first year of an undergraduate program in biosystems engineering have been designed and implemented. These activities were designed to put two modelling approaches side by side, an individual-based model and a set of ordinary differential equations. In order to organize and display this, a system with wolves and sheep in a confined domain was considered and studied. With the teaching material elaborated and a computer to perform the numerical resolutions involved and the corresponding individual-based simulations, the students answered questions and completed exercises to achieve the learning goals set. Students' responses regarding the modelling of biological systems and these two distinct methodologies applied to the study of a predator-prey system were collected via questionnaires, open-ended queries and face-to-face dialogues. Taking into account the positive responses of the students when they were doing these activities, it was clear that using a discrete individual-based model to deal with a predator-prey system jointly with a set of ordinary differential equations enriches the understanding of the modelling process, adds new insights and opens novel perspectives of what can be done with computational models versus other models. The complementary views given by the two modelling approaches were very well assessed by students.

  7. Using GAMM to examine inter-individual heterogeneity in thermal performance curves for Natrix natrix indicates bet hedging strategy by mothers.

    Science.gov (United States)

    Vickers, Mathew J; Aubret, Fabien; Coulon, Aurélie

    2017-01-01

    The thermal performance curve (TPC) illustrates the dependence on body- and therefore environmental- temperature of many fitness-related aspects of ectotherm ecology and biology including foraging, growth, predator avoidance, and reproduction. The typical thermal performance curve model is linear in its parameters despite the well-known, strong, non-linearity of the response of performance to temperature. In addition, it is usual to consider a single model based on few individuals as descriptive of a species-level response to temperature. To overcome these issues, we used generalized additive mixed modeling (GAMM) to estimate thermal performance curves for 73 individual hatchling Natrix natrix grass snakes from seven clutches, taking advantage of the structure of GAMM to demonstrate that almost 16% of the deviance in thermal performance curves is attributed to inter-individual variation, while only 1.3% is attributable to variation amongst clutches. GAMM allows precise estimation of curve characteristics, which we used to test hypotheses on tradeoffs thought to constrain the thermal performance curve: hotter is better, the specialist-generalist trade off, and resource allocation/acquisition. We observed a negative relationship between maximum performance and performance breadth, indicating a specialist-generalist tradeoff, and a positive relationship between thermal optimum and maximum performance, suggesting "hotter is better". There was a significant difference among matrilines in the relationship between Area Under the Curve and maximum performance - relationship that is an indicator of evenness in acquisition or allocation of resources. As we used unfed hatchlings, the observed matriline effect indicates divergent breeding strategies among mothers, with some mothers provisioning eggs unequally resulting in some offspring being better than others, while other mothers provisioned the eggs more evenly, resulting in even performance throughout the clutch. This

  8. Predicting Individual Physiological Responses During Marksmanship Field Training Using an Updated SCENARIO-J Model

    National Research Council Canada - National Science Library

    Yokota, Miyo

    2004-01-01

    ...)) for individual variation and a metabolic rate (M) correction during downhill movements. This study evaluated the updated version of the model incorporating these new features, using a dataset collected during U.S. Marine Corps (USMC...

  9. Teachers’ individual action theories about competence-based education: the value of the cognitive apprenticeship model

    NARCIS (Netherlands)

    Seezink, Audrey; Poell, Rob; Kirschner, Paul A.

    2009-01-01

    Seezink, A., Poell, R. F., & Kirschner, P. A. (2009). Teachers' individual action theories about competence-based education: The value of the cognitive apprenticeship model. Journal of Vocational Education & Training, 61, 203-215.

  10. A conceptual model to improve performance in virtual teams

    Directory of Open Access Journals (Sweden)

    Shopee Dube

    2016-09-01

    Full Text Available Background: The vast improvement in communication technologies and sophisticated project management tools, methods and techniques has allowed geographically and culturally diverse groups to operate and function in a virtual environment. To succeed in this virtual environment where time and space are becoming increasingly irrelevant, organisations must define new ways of implementing initiatives. This virtual environment phenomenon has brought about the formation of virtual project teams that allow organisations to harness the skills and knowhow of the best resources, irrespective of their location. Objectives: The aim of this article was to investigate performance criteria and develop a conceptual model which can be applied to enhance the success of virtual project teams. There are no clear guidelines of the performance criteria in managing virtual project teams. Method: A qualitative research methodology was used in this article. The purpose of content analysis was to explore the literature to understand the concept of performance in virtual project teams and to summarise the findings of the literature reviewed. Results: The research identified a set of performance criteria for the virtual project teams as follows: leadership, trust, communication, team cooperation, reliability, motivation, comfort and social interaction. These were used to conceptualise the model. Conclusion: The conceptual model can be used in a holistic way to determine the overall performance of the virtual project team, but each factor can be analysed individually to determine the impact on the overall performance. The knowledge of performance criteria for virtual project teams could aid project managers in enhancing the success of these teams and taking a different approach to better manage and coordinate them.

  11. Individualizing Services, Individualizing Responsibility

    DEFF Research Database (Denmark)

    Garsten, Christina; Hollertz, Katarina; Jacobsson, Kerstin

    possibilities for individual voice, autonomy and self-determination in the local delivery of activation policy? What barriers do specific organisational models and practices imply for clients to choose, determine and access tailor-made programmes and services? What policy technologies are at work in governing......-oriented, and the normative demands placed on individuals appear increasingly totalizing, concerning the whole individual rather than the job-related aspects only. The paper is based on 23 in-depth interviews with individual clients as well as individual caseworkers and other professionals engaged in client-related work...

  12. Assessing the Effects of Organizational Culture, Rewards, and Individual Creativity on Technical Workgroup Performance

    Science.gov (United States)

    Navaresse, Daniel O.; Yauch, Charlene A.; Goff, Kathy; Fonseca, Daniel J.

    2014-01-01

    This study used an experimental approach to investigate the conditions under which creative outcomes should be expected from the interplay of individual creativity, the innovation orientation of the organizational culture, and the rewards distribution rules. The results of this study suggest that the individual creativity of technically educated…

  13. The effects of environmental and individual quality on reproductive performance : A case study on blue tits

    NARCIS (Netherlands)

    Amininasab, Seyed Mehdi

    2016-01-01

    Birds have specific energetic requirements which likely depend on the habitat type they inhabit and on specific individual traits. Here, I investigated the effects of environmental quality (habitat quality and ambient temperature) and individual quality (age and/or lifespan) on features of

  14. Model for measuring complex performance in an aviation environment

    International Nuclear Information System (INIS)

    Hahn, H.A.

    1988-01-01

    An experiment was conducted to identify models of pilot performance through the attainment and analysis of concurrent verbal protocols. Sixteen models were identified. Novice and expert pilots differed with respect to the models they used. Models were correlated to performance, particularly in the case of expert subjects. Models were not correlated to performance shaping factors (i.e. workload). 3 refs., 1 tab

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

    NARCIS (Netherlands)

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

    2016-01-01

    This study examines inter-individual differences in how presentation modality affects verbal learning performance. Children aged 5 to 16 performed a verbal learning test within one of three presentation modalities: pictorial, auditory, or textual. The results indicated that a beneficial effect of

  16. Numerical modeling capabilities to predict repository performance

    International Nuclear Information System (INIS)

    1979-09-01

    This report presents a summary of current numerical modeling capabilities that are applicable to the design and performance evaluation of underground repositories for the storage of nuclear waste. The report includes codes that are available in-house, within Golder Associates and Lawrence Livermore Laboratories; as well as those that are generally available within the industry and universities. The first listing of programs are in-house codes in the subject areas of hydrology, solute transport, thermal and mechanical stress analysis, and structural geology. The second listing of programs are divided by subject into the following categories: site selection, structural geology, mine structural design, mine ventilation, hydrology, and mine design/construction/operation. These programs are not specifically designed for use in the design and evaluation of an underground repository for nuclear waste; but several or most of them may be so used

  17. Individual Feedback Propensities and Their Effects on Motivation, Training Success, and Performance

    National Research Council Canada - National Science Library

    Herols, David

    1997-01-01

    .... These propensities, if identified and measured, would be related to skill acquisition, performance improvement, self regulatory processes, performance maintenance, as well as a variety of affective...

  18. Modelling saline intrusion for repository performance assessment

    International Nuclear Information System (INIS)

    Jackson, C.P.

    1989-04-01

    UK Nirex Ltd are currently considering the possibility of disposal of radioactive waste by burial in deep underground repositories. The natural pathway for radionuclides from such a repository to return to Man's immediate environment (the biosphere) is via groundwater. Thus analyses of the groundwater flow in the neighbourhood of a possible repository, and consequent radionuclide transport form an important part of a performance assessment for a repository. Some of the areas in the UK that might be considered as possible locations for a repository are near the coast. If a repository is located in a coastal region seawater may intrude into the groundwater flow system. As seawater is denser than fresh water buoyancy forces acting on the intruding saline water may have significant effects on the groundwater flow system, and consequently on the time for radionuclides to return to the biosphere. Further, the chemistry of the repository near-field may be strongly influenced by the salinity of the groundwater. It is therefore important for Nirex to have a capability for reliably modelling saline intrusion to an appropriate degree of accuracy in order to make performance assessments for a repository in a coastal region. This report describes work undertaken in the Nirex Research programme to provide such a capability. (author)

  19. The Use of the Performance Diagnostic Checklist-Human Services to Assess and Improve the Job Performance of Individuals with Intellectual Disabilities.

    Science.gov (United States)

    Smith, Madison; Wilder, David A

    2018-06-01

    The Performance Diagnostic Checklist-Human Services (PDC-HS) is an informant-based tool designed to identify the variables responsible for performance problems. To date, the PDC-HS has not been examined with individuals with intellectual disabilities. In the current study, two supervisors with intellectual disabilities completed the PDC-HS to assess the productivity of two supervisees with disabilities who performed a pricing task in a thrift store. The PDC-HS suggested that performance deficits were due to a lack of training; a PDC-HS-indicated intervention was effective to increase accurate pricing. • The PDC-HS is an informant-based tool designed to identify the variables responsible for employee performance problems in human service settings. • The PDC-HS can be completed by some individuals with intellectual disabilities in a supervisory position to identify the variables responsible for problematic job performance among their supervisees. • A PDC-HS indicated intervention was demonstrated to be effective to improve the job performance of individuals with disabilities. • The PDC-HS may be a useful tool to support performance improvement and job maintenance among individuals with intellectual disabilities.

  20. Annual individual hygienic assessment of natural exposure doses of the Altai territory model areas population

    Directory of Open Access Journals (Sweden)

    N. Yu. Potseluev

    2016-01-01

    Full Text Available The goal is to determine ionizing radiation natural sources exposure regularities of Altai Territory model areas population. The materials and methods. 11376 radon measurements, 1247 gamma radiation meas-urements in an open area and in residential and office buildings were performed, selection of 189 drinking water tests was carried out. Results. Complex radiation and hygienic examination of the region with the most large municipalities number with model areas allocation was conducted. The assessment of the Altai Territory population’s individual annual radiation doses from natural radionuclides has revealed a number of the regularities depending on the terrain’s ecological and geographical type. Following the research results, ranging the region territories taking into account of annual effective doses of the population from natural sources for 2009-2015 was carried out. The annual individual effective dose of the Altai Territory upland areas population presented by the highest values and ranges from 7.36 mSv / year to 8.19 mSv / year. Foothill regions of Altai and in Salair ridge are characterized by increased population exposure from natural sources. Here the dose ranges from 5.09 mSv / year to 6.22 mSv / year. Steppe and forest-steppe territories are characterized by the lowest level of the natural radiation which is ranging from 3.23 mSv / year to 4.11 mSv / year, that doesn’t exceed the all-Russian levels. Most of the hygienic radon equivalent equilibrium volume activity standards exceedances were registered in mountain and foothill areas buildings. A number of radon anomalies is revealed also in steppe areas. Med exceedances ranged from 203 ± 17.8 Bq / m3 to 480 ± 37.9 Bq / m3. Given the fact that most of these buildings belong to the administrative or educational institutions with an eight-hour working day, the dose of radiation for people there can be up to 10 mSv / year. Conclusion. Spreading of individual annual effective

  1. Towards Linking 3D SAR and Lidar Models with a Spatially Explicit Individual Based Forest Model

    Science.gov (United States)

    Osmanoglu, B.; Ranson, J.; Sun, G.; Armstrong, A. H.; Fischer, R.; Huth, A.

    2017-12-01

    In this study, we present a parameterization of the FORMIND individual-based gap model (IBGM)for old growth Atlantic lowland rainforest in La Selva, Costa Rica for the purpose of informing multisensor remote sensing techniques for above ground biomass techniques. The model was successfully parameterized and calibrated for the study site; results show that the simulated forest reproduces the structural complexity of Costa Rican rainforest based on comparisons with CARBONO inventory plot data. Though the simulated stem numbers (378) slightly underestimated the plot data (418), particularly for canopy dominant intermediate shade tolerant trees and shade tolerant understory trees, overall there was a 9.7% difference. Aboveground biomass (kg/ha) showed a 0.1% difference between the simulated forest and inventory plot dataset. The Costa Rica FORMIND simulation was then used to parameterize a spatially explicit (3D) SAR and lidar backscatter models. The simulated forest stands were used to generate a Look Up Table as a tractable means to estimate aboveground forest biomass for these complex forests. Various combinations of lidar and radar variables were evaluated in the LUT inversion. To test the capability of future data for estimation of forest height and biomass, we considered data of 1) L- (or P-) band polarimetric data (backscattering coefficients of HH, HV and VV); 2) L-band dual-pol repeat-pass InSAR data (HH/HV backscattering coefficients and coherences, height of scattering phase center at HH and HV using DEM or surface height from lidar data as reference); 3) P-band polarimetric InSAR data (canopy height from inversion of PolInSAR data or use the coherences and height of scattering phase center at HH, HV and VV); 4) various height indices from waveform lidar data); and 5) surface and canopy top height from photon-counting lidar data. The methods for parameterizing the remote sensing models with the IBGM and developing Look Up Tables will be discussed. Results

  2. High-performance phase-field modeling

    KAUST Repository

    Vignal, Philippe

    2015-04-27

    Many processes in engineering and sciences involve the evolution of interfaces. Among the mathematical frameworks developed to model these types of problems, the phase-field method has emerged as a possible solution. Phase-fields nonetheless lead to complex nonlinear, high-order partial differential equations, whose solution poses mathematical and computational challenges. Guaranteeing some of the physical properties of the equations has lead to the development of efficient algorithms and discretizations capable of recovering said properties by construction [2, 5]. This work builds-up on these ideas, and proposes novel discretization strategies that guarantee numerical energy dissipation for both conserved and non-conserved phase-field models. The temporal discretization is based on a novel method which relies on Taylor series and ensures strong energy stability. It is second-order accurate, and can also be rendered linear to speed-up the solution process [4]. The spatial discretization relies on Isogeometric Analysis, a finite element method that possesses the k-refinement technology and enables the generation of high-order, high-continuity basis functions. These basis functions are well suited to handle the high-order operators present in phase-field models. Two-dimensional and three dimensional results of the Allen-Cahn, Cahn-Hilliard, Swift-Hohenberg and phase-field crystal equation will be presented, which corroborate the theoretical findings, and illustrate the robustness of the method. Results related to more challenging examples, namely the Navier-Stokes Cahn-Hilliard and a diusion-reaction Cahn-Hilliard system, will also be presented. The implementation was done in PetIGA and PetIGA-MF, high-performance Isogeometric Analysis frameworks [1, 3], designed to handle non-linear, time-dependent problems.

  3. Changes in speed distribution: Applying aggregated safety effect models to individual vehicle speeds.

    Science.gov (United States)

    Vadeby, Anna; Forsman, Åsa

    2017-06-01

    This study investigated the effect of applying two aggregated models (the Power model and the Exponential model) to individual vehicle speeds instead of mean speeds. This is of particular interest when the measure introduced affects different parts of the speed distribution differently. The aim was to examine how the estimated overall risk was affected when assuming the models are valid on an individual vehicle level. Speed data from two applications of speed measurements were used in the study: an evaluation of movable speed cameras and a national evaluation of new speed limits in Sweden. The results showed that when applied on individual vehicle speed level compared with aggregated level, there was essentially no difference between these for the Power model in the case of injury accidents. However, for fatalities the difference was greater, especially for roads with new cameras where those driving fastest reduced their speed the most. For the case with new speed limits, the individual approach estimated a somewhat smaller effect, reflecting that changes in the 15th percentile (P15) were somewhat larger than changes in P85 in this case. For the Exponential model there was also a clear, although small, difference between applying the model to mean speed changes and individual vehicle speed changes when speed cameras were used. This applied both for injury accidents and fatalities. There were also larger effects for the Exponential model than for the Power model, especially for injury accidents. In conclusion, applying the Power or Exponential model to individual vehicle speeds is an alternative that provides reasonable results in relation to the original Power and Exponential models, but more research is needed to clarify the shape of the individual risk curve. It is not surprising that the impact on severe traffic crashes was larger in situations where those driving fastest reduced their speed the most. Further investigations on use of the Power and/or the

  4. Performance modelling for product development of advanced window systems

    DEFF Research Database (Denmark)

    Appelfeld, David

    properties (chapter 5) of CFSs. The last chapter concludes the thesis and the individual investigations. It is complicated to holistically evaluate the performance of a prototyped system, since simulation programs evaluate standardised products such as aluminium venetian blinds. State-of-the-art tools......The research presented in this doctoral thesis shows how the product development (PD) of Complex Fenestration Systems (CFSs) can be facilitated by computer-based analysis to improve the energy efficiency of fenestration systems as well as to improve the indoor environment. The first chapter defines...... the hypothesis and objectives of the thesis, which is followed by an extended introduction and background. The third chapter briefly suggests the PD framework which is suitable for CFSs. The fourth and fifth chapter refer to the detailed performance modelling of thermal properties (chapter 4) and optical...

  5. Developing an agent-based model on how different individuals solve complex problems

    Directory of Open Access Journals (Sweden)

    Ipek Bozkurt

    2015-01-01

    Full Text Available Purpose: Research that focuses on the emotional, mental, behavioral and cognitive capabilities of individuals has been abundant within disciplines such as psychology, sociology, and anthropology, among others. However, when facing complex problems, a new perspective to understand individuals is necessary. The main purpose of this paper is to develop an agent-based model and simulation to gain understanding on the decision-making and problem-solving abilities of individuals. Design/Methodology/approach: The micro-level analysis modeling and simulation paradigm Agent-Based Modeling Through the use of Agent-Based Modeling, insight is gained on how different individuals with different profiles deal with complex problems. Using previous literature from different bodies of knowledge, established theories and certain assumptions as input parameters, a model is built and executed through a computer simulation. Findings: The results indicate that individuals with certain profiles have better capabilities to deal with complex problems. Moderate profiles could solve the entire complex problem, whereas profiles within extreme conditions could not. This indicates that having a strong predisposition is not the ideal way when approaching complex problems, and there should always be a component from the other perspective. The probability that an individual may use these capabilities provided by the opposite predisposition provides to be a useful option. Originality/value: The originality of the present research stems from how individuals are profiled, and the model and simulation that is built to understand how they solve complex problems. The development of the agent-based model adds value to the existing body of knowledge within both social sciences, and modeling and simulation.

  6. Individual Skills Based Volunteerism and Life Satisfaction among Healthcare Volunteers in Malaysia: Role of Employer Encouragement, Self-Esteem and Job Performance, A Cross-Sectional Study

    Science.gov (United States)

    Veerasamy, Chanthiran; Sambasivan, Murali; Kumar, Naresh

    2013-01-01

    The purpose of this paper is to analyze two important outcomes of individual skills-based volunteerism (ISB-V) among healthcare volunteers in Malaysia. The outcomes are: job performance and life satisfaction. This study has empirically tested the impact of individual dimensions of ISB-V along with their inter-relationships in explaining the life satisfaction and job performance. Besides, the effects of employer encouragement to the volunteers, demographic characteristics of volunteers, and self-esteem of volunteers on job performance and life satisfaction have been studied. The data were collected through a questionnaire distributed to 1000 volunteers of St. John Ambulance in Malaysia. Three hundred and sixty six volunteers responded by giving their feedback. The model was tested using Structural Equation Modeling (SEM). The main results of this study are: (1) Volunteer duration and nature of contact affects life satisfaction, (2) volunteer frequency has impact on volunteer duration, (3) self-esteem of volunteers has significant relationships with volunteer frequency, job performance and life satisfaction, (4) job performance of volunteers affect their life satisfaction and (5) current employment level has significant relationships with duration of volunteering, self esteem, employer encouragement and job performance of volunteers. The model in this study has been able to explain 39% of the variance in life satisfaction and 45% of the variance in job performance. The current study adds significantly to the body of knowledge on healthcare volunteerism. PMID:24194894

  7. Individual skills based volunteerism and life satisfaction among healthcare volunteers in Malaysia: role of employer encouragement, self-esteem and job performance, a cross-sectional study.

    Science.gov (United States)

    Veerasamy, Chanthiran; Sambasivan, Murali; Kumar, Naresh

    2013-01-01

    The purpose of this paper is to analyze two important outcomes of individual skills-based volunteerism (ISB-V) among healthcare volunteers in Malaysia. The outcomes are: job performance and life satisfaction. This study has empirically tested the impact of individual dimensions of ISB-V along with their inter-relationships in explaining the life satisfaction and job performance. Besides, the effects of employer encouragement to the volunteers, demographic characteristics of volunteers, and self-esteem of volunteers on job performance and life satisfaction have been studied. The data were collected through a questionnaire distributed to 1000 volunteers of St. John Ambulance in Malaysia. Three hundred and sixty six volunteers responded by giving their feedback. The model was tested using Structural Equation Modeling (SEM). The main results of this study are: (1) Volunteer duration and nature of contact affects life satisfaction, (2) volunteer frequency has impact on volunteer duration, (3) self-esteem of volunteers has significant relationships with volunteer frequency, job performance and life satisfaction, (4) job performance of volunteers affect their life satisfaction and (5) current employment level has significant relationships with duration of volunteering, self esteem, employer encouragement and job performance of volunteers. The model in this study has been able to explain 39% of the variance in life satisfaction and 45% of the variance in job performance. The current study adds significantly to the body of knowledge on healthcare volunteerism.

  8. Individual skills based volunteerism and life satisfaction among healthcare volunteers in Malaysia: role of employer encouragement, self-esteem and job performance, a cross-sectional study.

    Directory of Open Access Journals (Sweden)

    Chanthiran Veerasamy

    Full Text Available The purpose of this paper is to analyze two important outcomes of individual skills-based volunteerism (ISB-V among healthcare volunteers in Malaysia. The outcomes are: job performance and life satisfaction. This study has empirically tested the impact of individual dimensions of ISB-V along with their inter-relationships in explaining the life satisfaction and job performance. Besides, the effects of employer encouragement to the volunteers, demographic characteristics of volunteers, and self-esteem of volunteers on job performance and life satisfaction have been studied. The data were collected through a questionnaire distributed to 1000 volunteers of St. John Ambulance in Malaysia. Three hundred and sixty six volunteers responded by giving their feedback. The model was tested using Structural Equation Modeling (SEM. The main results of this study are: (1 Volunteer duration and nature of contact affects life satisfaction, (2 volunteer frequency has impact on volunteer duration, (3 self-esteem of volunteers has significant relationships with volunteer frequency, job performance and life satisfaction, (4 job performance of volunteers affect their life satisfaction and (5 current employment level has significant relationships with duration of volunteering, self esteem, employer encouragement and job performance of volunteers. The model in this study has been able to explain 39% of the variance in life satisfaction and 45% of the variance in job performance. The current study adds significantly to the body of knowledge on healthcare volunteerism.

  9. Stochastic Individual-Based Modeling of Bacterial Growth and Division Using Flow Cytometry

    Directory of Open Access Journals (Sweden)

    Míriam R. García

    2018-01-01

    Full Text Available A realistic description of the variability in bacterial growth and division is critical to produce reliable predictions of safety risks along the food chain. Individual-based modeling of bacteria provides the theoretical framework to deal with this variability, but it requires information about the individual behavior of bacteria inside populations. In this work, we overcome this problem by estimating the individual behavior of bacteria from population statistics obtained with flow cytometry. For this objective, a stochastic individual-based modeling framework is defined based on standard assumptions during division and exponential growth. The unknown single-cell parameters required for running the individual-based modeling simulations, such as cell size growth rate, are estimated from the flow cytometry data. Instead of using directly the individual-based model, we make use of a modified Fokker-Plank equation. This only equation simulates the population statistics in function of the unknown single-cell parameters. We test the validity of the approach by modeling the growth and division of Pediococcus acidilactici within the exponential phase. Estimations reveal the statistics of cell growth and division using only data from flow cytometry at a given time. From the relationship between the mother and daughter volumes, we also predict that P. acidilactici divide into two successive parallel planes.

  10. Analysis of the Effect of Individual Characteristics, Employees’ Competency and Organizational Climate on Job Satisfaction and Employees’ Performance at a State-Owned Trading Company in Indonesia

    Directory of Open Access Journals (Sweden)

    SYAIFUDDIN

    2017-08-01

    Full Text Available Job satisfaction and employees’ performance are important for the organization to improve the company's competitive value. This research aims to know the influence of individual characteristic, employees’ competency and organizational climate toward job satisfaction and its implication on employees’ performance. The research method used in this research is cross sectional survey. The population of this research was from 4 cities with a total sample of 51 employees. Moreover, this research applied structural equation modeling with Partial Least Square approach for analyzing the data. The results showed that individual characteristics do not effect on job satisfaction, while employees’ competency and organizational climate have a significant effect on job satisfaction. Then, job satisfaction has a significant effect on employees’ performance. It is necessary to conduct training and education programs along with flexible structural support and adequate rewards for the employees to improve the job satisfaction. Those aspects are expected to improve the employees’ performance.

  11. Structure and sensitivity analysis of individual-based predator–prey models

    International Nuclear Information System (INIS)

    Imron, Muhammad Ali; Gergs, Andre; Berger, Uta

    2012-01-01

    The expensive computational cost of sensitivity analyses has hampered the use of these techniques for analysing individual-based models in ecology. A relatively cheap computational cost, referred to as the Morris method, was chosen to assess the relative effects of all parameters on the model’s outputs and to gain insights into predator–prey systems. Structure and results of the sensitivity analysis of the Sumatran tiger model – the Panthera Population Persistence (PPP) and the Notonecta foraging model (NFM) – were compared. Both models are based on a general predation cycle and designed to understand the mechanisms behind the predator–prey interaction being considered. However, the models differ significantly in their complexity and the details of the processes involved. In the sensitivity analysis, parameters that directly contribute to the number of prey items killed were found to be most influential. These were the growth rate of prey and the hunting radius of tigers in the PPP model as well as attack rate parameters and encounter distance of backswimmers in the NFM model. Analysis of distances in both of the models revealed further similarities in the sensitivity of the two individual-based models. The findings highlight the applicability and importance of sensitivity analyses in general, and screening design methods in particular, during early development of ecological individual-based models. Comparison of model structures and sensitivity analyses provides a first step for the derivation of general rules in the design of predator–prey models for both practical conservation and conceptual understanding. - Highlights: ► Structure of predation processes is similar in tiger and backswimmer model. ► The two individual-based models (IBM) differ in space formulations. ► In both models foraging distance is among the sensitive parameters. ► Morris method is applicable for the sensitivity analysis even of complex IBMs.

  12. Performance and process in collective and individual memory: the role of social decision schemes and memory bias in collective memory.

    Science.gov (United States)

    Van Swol, Lyn M

    2008-04-01

    To assess performance and processes in collective and individual memory, participants watched two job candidates on video. Beforehand, half the participants were told they would be tested on their memory of the interviews, and the other half were asked to make a decision to hire one of the candidates. Afterwards, participants completed a recognition memory task in either a group or individual condition. Groups had better recognition memory than individuals. Individuals made more false positives than false negatives and groups exaggerated this. Post-hoc analysis found that groups only exaggerated the tendency towards false positives on items that reflected negatively on the job candidate. There was no significant difference between instruction conditions. When reaching consensus on the recognition task, groups tended to choose the correct answer if at least two members had the correct answer. This method of consensus is discussed as a factor in groups' superior memory performance.

  13. Probabilistic Inference: Task Dependency and Individual Differences of Probability Weighting Revealed by Hierarchical Bayesian Modeling.

    Science.gov (United States)

    Boos, Moritz; Seer, Caroline; Lange, Florian; Kopp, Bruno

    2016-01-01

    Cognitive determinants of probabilistic inference were examined using hierarchical Bayesian modeling techniques. A classic urn-ball paradigm served as experimental strategy, involving a factorial two (prior probabilities) by two (likelihoods) design. Five computational models of cognitive processes were compared with the observed behavior. Parameter-free Bayesian posterior probabilities and parameter-free base rate neglect provided inadequate models of probabilistic inference. The introduction of distorted subjective probabilities yielded more robust and generalizable results. A general class of (inverted) S-shaped probability weighting functions had been proposed; however, the possibility of large differences in probability distortions not only across experimental conditions, but also across individuals, seems critical for the model's success. It also seems advantageous to consider individual differences in parameters of probability weighting as being sampled from weakly informative prior distributions of individual parameter values. Thus, the results from hierarchical Bayesian modeling converge with previous results in revealing that probability weighting parameters show considerable task dependency and individual differences. Methodologically, this work exemplifies the usefulness of hierarchical Bayesian modeling techniques for cognitive psychology. Theoretically, human probabilistic inference might be best described as the application of individualized strategic policies for Bayesian belief revision.

  14. Driving-forces model on individual behavior in scenarios considering moving threat agents

    Science.gov (United States)

    Li, Shuying; Zhuang, Jun; Shen, Shifei; Wang, Jia

    2017-09-01

    The individual behavior model is a contributory factor to improve the accuracy of agent-based simulation in different scenarios. However, few studies have considered moving threat agents, which often occur in terrorist attacks caused by attackers with close-range weapons (e.g., sword, stick). At the same time, many existing behavior models lack validation from cases or experiments. This paper builds a new individual behavior model based on seven behavioral hypotheses. The driving-forces model is an extension of the classical social force model considering scenarios including moving threat agents. An experiment was conducted to validate the key components of the model. Then the model is compared with an advanced Elliptical Specification II social force model, by calculating the fitting errors between the simulated and experimental trajectories, and being applied to simulate a specific circumstance. Our results show that the driving-forces model reduced the fitting error by an average of 33.9% and the standard deviation by an average of 44.5%, which indicates the accuracy and stability of the model in the studied situation. The new driving-forces model could be used to simulate individual behavior when analyzing the risk of specific scenarios using agent-based simulation methods, such as risk analysis of close-range terrorist attacks in public places.

  15. Why Are Some More Peer Than Others? Evidence from a Longitudinal Study of Social Networks and Individual Academic Performance

    OpenAIRE

    Lomi, Alessandro; Snijders, Tom A.B.; Steglich, Christian E.G.; Torlo, Vanina Jasmine

    2011-01-01

    Studies of peer effects in educational settings confront two main problems. The first is the presence of endogenous sorting which confounds the effects of social influence and social selection on individual attainment. The second is how to account for the local network dependencies through which peer effects influence individual behavior. We empirically address these problems using longitudinal data on academic performance, friendship, and advice seeking relations among stud...

  16. Influence of Erroneous Patient Records on Population Pharmacokinetic Modeling and Individual Bayesian Estimation

    NARCIS (Netherlands)

    van der Meer, Aize Franciscus; Touw, Daniel J.; Marcus, Marco A. E.; Neef, Cornelis; Proost, Johannes H.

    2012-01-01

    Background: Observational data sets can be used for population pharmacokinetic (PK) modeling. However, these data sets are generally less precisely recorded than experimental data sets. This article aims to investigate the influence of erroneous records on population PK modeling and individual

  17. An individual-based model of Zebrafish population dynamics accounting for energy dynamics

    DEFF Research Database (Denmark)

    Beaudouin, Remy; Goussen, Benoit; Piccini, Benjamin

    2015-01-01

    Developing population dynamics models for zebrafish is crucial in order to extrapolate from toxicity data measured at the organism level to biological levels relevant to support and enhance ecological risk assessment. To achieve this, a dynamic energy budget for individual zebrafish (DEB model...

  18. The influence of societal individualism on a century of tobacco use: modelling the prevalence of smoking.

    Science.gov (United States)

    Lang, John C; Abrams, Daniel M; De Sterck, Hans

    2015-12-22

    Smoking of tobacco is estimated to have caused approximately six million deaths worldwide in 2014. Responding effectively to this epidemic requires a thorough understanding of how smoking behaviour is transmitted and modified. We present a new mathematical model of the social dynamics that cause cigarette smoking to spread in a population, incorporating aspects of individual and social utility. Model predictions are tested against two independent data sets spanning 25 countries: a newly compiled century-long composite data set on smoking prevalence, and Hofstede's individualism/collectivism measure (IDV). The general model prediction that more individualistic societies will show faster adoption and cessation of smoking is supported by the full 25 country smoking prevalence data set. Calibration of the model to the available smoking prevalence data is possible in a subset of 7 countries. Consistency of fitted model parameters with an additional, independent, data set further supports our model: the fitted value of the country-specific model parameter that determines the relative importance of social and individual factors in the decision of whether or not to smoke, is found to be significantly correlated with Hofstede's IDV for the 25 countries in our data set. Our model in conjunction with extensive data on smoking prevalence provides evidence for the hypothesis that individualism/collectivism may have an important influence on the dynamics of smoking prevalence at the aggregate, population level. Significant implications for public health interventions are discussed.

  19. The Limit Behavior of a Stochastic Logistic Model with Individual Time-Dependent Rates

    Directory of Open Access Journals (Sweden)

    Yilun Shang

    2013-01-01

    Full Text Available We investigate a variant of the stochastic logistic model that allows individual variation and time-dependent infection and recovery rates. The model is described as a heterogeneous density dependent Markov chain. We show that the process can be approximated by a deterministic process defined by an integral equation as the population size grows.

  20. Effect of hypoxia and hyperoxia on exercise performance in healthy individuals and in patients with pulmonary hypertension: a systematic review.

    Science.gov (United States)

    Ulrich, Silvia; Schneider, Simon R; Bloch, Konrad E

    2017-12-01

    Exercise performance is determined by oxygen supply to working muscles and vital organs. In healthy individuals, exercise performance is limited in the hypoxic environment at altitude, when oxygen delivery is diminished due to the reduced alveolar and arterial oxygen partial pressures. In patients with pulmonary hypertension (PH), exercise performance is already reduced near sea level due to impairments of the pulmonary circulation and gas exchange, and, presumably, these limitations are more pronounced at altitude. In studies performed near sea level in healthy subjects, as well as in patients with PH, maximal performance during progressive ramp exercise and endurance of submaximal constant-load exercise were substantially enhanced by breathing oxygen-enriched air. Both in healthy individuals and in PH patients, these improvements were mediated by a better arterial, muscular, and cerebral oxygenation, along with a reduced sympathetic excitation, as suggested by the reduced heart rate and alveolar ventilation at submaximal isoloads, and an improved pulmonary gas exchange efficiency, especially in patients with PH. In summary, in healthy individuals and in patients with PH, alterations in the inspiratory Po 2 by exposure to hypobaric hypoxia or normobaric hyperoxia reduce or enhance exercise performance, respectively, by modifying oxygen delivery to the muscles and the brain, by effects on cardiovascular and respiratory control, and by alterations in pulmonary gas exchange. The understanding of these physiological mechanisms helps in counselling individuals planning altitude or air travel and prescribing oxygen therapy to patients with PH.

  1. Understanding Individual Resilience in the Workplace: The International Collaboration of Workforce Resilience (ICWR) Model

    OpenAIRE

    Clare Samantha Rees; Lauren J Breen; Lynette eCusack; Desley eHegney

    2015-01-01

    When not managed effectively, high levels of workplace stress can lead to several negative personal and performance outcomes. Some professional groups work in highly stressful settings and are therefore particularly at risk of conditions such as anxiety, depression, secondary traumatic stress and burnout. However, some individuals are less affected by workplace stress and the associated negative outcomes. Such individuals have been described as ‘resilient’. A number of studies have found rela...

  2. Understanding individual resilience in the workplace: the international collaboration of workforce resilience model

    OpenAIRE

    Rees, Clare S.; Breen, Lauren J.; Cusack, Lynette; Hegney, Desley

    2015-01-01

    When not managed effectively, high levels of workplace stress can lead to several negative personal and performance outcomes. Some professional groups work in highly stressful settings and are therefore particularly at risk of conditions such as anxiety, depression, secondary traumatic stress, and burnout. However, some individuals are less affected by workplace stress and the associated negative outcomes. Such individuals have been described as “resilient.” A number of studies have found rel...

  3. Benefits of spatiotemporal modeling for short-term wind power forecasting at both individual and aggregated levels

    DEFF Research Database (Denmark)

    Lenzi, Amanda; Steinsland, Ingelin; Pinson, Pierre

    2018-01-01

    The share of wind energy in total installed power capacity has grown rapidly in recent years. Producing accurate and reliable forecasts of wind power production, together with a quantification of the uncertainty, is essential to optimally integrate wind energy into power systems. We build...... spatiotemporal models for wind power generation and obtain full probabilistic forecasts from 15 min to 5 h ahead. Detailed analyses of forecast performances on individual wind farms and aggregated wind power are provided. The predictions from our models are evaluated on a data set from wind farms in western...... Denmark using a sliding window approach, for which estimation is performed using only the last available measurements. The case study shows that it is important to have a spatiotemporal model instead of a temporal one to achieve calibrated aggregated forecasts. Furthermore, spatiotemporal models have...

  4. Investigating pianists' individuality in the performance of five timbral nuances through patterns of articulation, touch, dynamics and pedalling

    Directory of Open Access Journals (Sweden)

    Michel eBernays

    2014-03-01

    Full Text Available Timbre is an essential expressive feature in piano performance. Concert pianists use a vast palette of timbral nuances to colour their performances at the microstructural level. Although timbre is generally envisioned in the pianistic community as an abstract concept carried through an imaged vocabulary, performers may share some common strategies of timbral expression in piano performance. Yet there may remain further leeway for idiosyncratic processes in the production of piano timbre nuances. In this study, we examined the patterns of timbral expression in performances by four expert pianists. Each pianist performed four short pieces, each with five different timbral intentions (bright, dark, dry, round, and velvety. The performances were recorded with the high-accuracy Bösendorfer CEUS system. Fine-grained performance features of dynamics, touch, articulation and pedalling were extracted. Reduced PCA performance spaces and descriptive performance portraits confirmed that pianists exhibited unique, specific profiles for different timbral intentions, derived from underlying traits of general individuality, while sharing some broad commonalities of dynamics and articulation for each timbral intention. These results confirm that pianists’ abstract notions of timbre correspond to reliable patterns of performance technique. Furthermore, these effects suggest that pianists can express individual styles while complying with specific timbral intentions.

  5. An individual-based model of skipjack tuna (Katsuwonus pelamis) movement in the tropical Pacific ocean

    Science.gov (United States)

    Scutt Phillips, Joe; Sen Gupta, Alex; Senina, Inna; van Sebille, Erik; Lange, Michael; Lehodey, Patrick; Hampton, John; Nicol, Simon

    2018-05-01

    The distribution of marine species is often modeled using Eulerian approaches, in which changes to population density or abundance are calculated at fixed locations in space. Conversely, Lagrangian, or individual-based, models simulate the movement of individual particles moving in continuous space, with broader-scale patterns such as distribution being an emergent property of many, potentially adaptive, individuals. These models offer advantages in examining dynamics across spatiotemporal scales and making comparisons with observations from individual-scale data. Here, we introduce and describe such a model, the Individual-based Kinesis, Advection and Movement of Ocean ANimAls model (Ikamoana), which we use to replicate the movement processes of an existing Eulerian model for marine predators (the Spatial Ecosystem and Population Dynamics Model, SEAPODYM). Ikamoana simulates the movement of either individual or groups of animals by physical ocean currents, habitat-dependent stochastic movements (kinesis), and taxis movements representing active searching behaviours. Applying our model to Pacific skipjack tuna (Katsuwonus pelamis), we show that it accurately replicates the evolution of density distribution simulated by SEAPODYM with low time-mean error and a spatial correlation of density that exceeds 0.96 at all times. We demonstrate how the Lagrangian approach permits easy tracking of individuals' trajectories for examining connectivity between different regions, and show how the model can provide independent estimates of transfer rates between commonly used assessment regions. In particular, we find that retention rates in most assessment regions are considerably smaller (up to a factor of 2) than those estimated by this population of skipjack's primary assessment model. Moreover, these rates are sensitive to ocean state (e.g. El Nino vs La Nina) and so assuming fixed transfer rates between regions may lead to spurious stock estimates. A novel feature of the

  6. Meningkatkan Prestasi Belajar IPS Materi Interaksi Sosial Melalui Penggunaan Model Pembelajaran Team Assisted Individualization (TAI

    Directory of Open Access Journals (Sweden)

    Juliastuti .

    2017-01-01

    is to implement cooperative learning model type TAI (Team Asissted Individualization. The purpose of this study was to describe the use of cooperative learning TAI to increase the percentage of the average: (1 each type of student activity; (2 The students' mastery of the material from cycle to cycle. This research is a class act who performed three cycles. Data of this study consisted of qualitative data, ie data on the activity of the student task derived from the observation sheets, as well as quantitative data such as the value of social interaction mastery of the material obtained through formative tests. The results of this study indicate that the use of cooperative learning model has a positive impact in improving student achievement marked by increased mastery learning students in each cycle, ie 65.63% the first cycle, the second cycle of 100% Keywords: Team Assisted Individualization (TAI, Achievement, IPS

  7. Baking oven improvement by performance modelling

    Energy Technology Data Exchange (ETDEWEB)

    1994-04-01

    The first phase of the project included both the derivation of an oven model and the development of a portable, rapid-response heat-flux sensor. Heat flux (defined as the instantaneous rate of heat flow per unit at the surface of the baking biscuit and expressed in W/cm[sup 2]) has been shown to be a more useful measure of oven performance than temperature alone. Fixed-point heat-flux sensors have already been developed and marketed, but a need was expressed at the start of this project for a travelling sensor which could be used to construct a more detailed picture of heat-flux variation in an oven. The travelling monitor developed can be used to measure variations in the heat flux experienced at the surface of products being baked in a travelling oven, both when oven conditions are fixed and when they are varied. It can also be used to identify the optimum locations within an oven for fixed heat-flux probes. It has been used effectively throughout the project for both purposes. Fuel savings of 18% and 21%, respectively, were achieved with two ovens. (author)

  8. Modelling and modal properties of the railway vehicle bogie with two individual wheelset drives

    Directory of Open Access Journals (Sweden)

    Zeman V.

    2007-10-01

    Full Text Available The paper deals with mathematical modelling of vibration and modal analysis of two-axled bogie of a railway vehicle. In comparison with recent publications introducing mathematical models of an individual wheelset drive, this paper is focused on modelling of complex bogie vibration. The bogie frame is linked by primary suspension to the two wheelset drives with hollow shafts and by secondary suspension to the car body. The method is based on the system decomposition into three subsystems – two individual wheelset drives including the mass of the rail and the bogie frame coupled with a half of the car body – and on modelling of couplings among subsystems. The eigenvalues of a linearized autonomous model and stability conditions are investigated in dependence on longitudinal creepage and forward velocity of the railway vehicle. The nonlinear model will be used for investigating the dynamic loading of bogie components caused by different types of excitation.

  9. Probabilistic inference: Task dependency and individual differences of probability weighting revealed by hierarchical Bayesian modelling

    Directory of Open Access Journals (Sweden)

    Moritz eBoos

    2016-05-01

    Full Text Available Cognitive determinants of probabilistic inference were examined using hierarchical Bayesian modelling techniques. A classic urn-ball paradigm served as experimental strategy, involving a factorial two (prior probabilities by two (likelihoods design. Five computational models of cognitive processes were compared with the observed behaviour. Parameter-free Bayesian posterior probabilities and parameter-free base rate neglect provided inadequate models of probabilistic inference. The introduction of distorted subjective probabilities yielded more robust and generalizable results. A general class of (inverted S-shaped probability weighting functions had been proposed; however, the possibility of large differences in probability distortions not only across experimental conditions, but also across individuals, seems critical for the model’s success. It also seems advantageous to consider individual differences in parameters of probability weighting as being sampled from weakly informative prior distributions of individual parameter values. Thus, the results from hierarchical Bayesian modelling converge with previous results in revealing that probability weighting parameters show considerable task dependency and individual differences. Methodologically, this work exemplifies the usefulness of hierarchical Bayesian modelling techniques for cognitive psychology. Theoretically, human probabilistic inference might be best described as the application of individualized strategic policies for Bayesian belief revision.

  10. Discrete-time moment closure models for epidemic spreading in populations of interacting individuals.

    Science.gov (United States)

    Frasca, Mattia; Sharkey, Kieran J

    2016-06-21

    Understanding the dynamics of spread of infectious diseases between individuals is essential for forecasting the evolution of an epidemic outbreak or for defining intervention policies. The problem is addressed by many approaches including stochastic and deterministic models formulated at diverse scales (individuals, populations) and different levels of detail. Here we consider discrete-time SIR (susceptible-infectious-removed) dynamics propagated on contact networks. We derive a novel set of 'discrete-time moment equations' for the probability of the system states at the level of individual nodes and pairs of nodes. These equations form a set which we close by introducing appropriate approximations of the joint probabilities appearing in them. For the example case of SIR processes, we formulate two types of model, one assuming statistical independence at the level of individuals and one at the level of pairs. From the pair-based model we then derive a model at the level of the population which captures the behavior of epidemics on homogeneous random networks. With respect to their continuous-time counterparts, the models include a larger number of possible transitions from one state to another and joint probabilities with a larger number of individuals. The approach is validated through numerical simulation over different network topologies. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. A Nonlinear Mixed Effects Model for the Prediction of Natural Gas Consumption by Individual Customers

    Czech Academy of Sciences Publication Activity Database

    Brabec, Marek; Konár, Ondřej; Pelikán, Emil; Malý, Marek

    2008-01-01

    Roč. 24, č. 4 (2008), s. 659-678 ISSN 0169-2070 R&D Projects: GA AV ČR 1ET400300513 Institutional research plan: CEZ:AV0Z10300504 Keywords : individual gas consumption * nonlinear mixed effects model * ARIMAX * ARX * generalized linear mixed model * conditional modeling Subject RIV: JE - Non-nuclear Energetics, Energy Consumption ; Use Impact factor: 1.685, year: 2008

  12. Exact solution of gyration radius of individual's trajectory for a simplified human mobility model

    OpenAIRE

    Yan, Xiao-Yong; Han, Xiao-Pu; Zhou, Tao; Wang, Bing-Hong

    2010-01-01

    Gyration radius of individual's trajectory plays a key role in quantifying human mobility patterns. Of particular interests, empirical analyses suggest that the growth of gyration radius is slow versus time except the very early stage and may eventually arrive to a steady value. However, up to now, the underlying mechanism leading to such a possibly steady value has not been well understood. In this Letter, we propose a simplified human mobility model to simulate individual's daily travel wit...

  13. Individual Travel Behavior Modeling of Public Transport Passenger Based on Graph Construction

    OpenAIRE

    Quan Liang; Jiancheng Weng; Wei Zhou; Selene Baez Santamaria; Jianming Ma; Jian Rong

    2018-01-01

    This paper presents a novel method for mining the individual travel behavior regularity of different public transport passengers through constructing travel behavior graph based model. The individual travel behavior graph is developed to represent spatial positions, time distributions, and travel routes and further forecasts the public transport passenger’s behavior choice. The proposed travel behavior graph is composed of macronodes, arcs, and transfer probability. Each macronode corresponds...

  14. Strong persistent growth differences govern individual performance and population dynamics in a tropical forest understorey palm

    NARCIS (Netherlands)

    Jansen, M.; Zuidema, P.A.; Anten, N.P.R.; Martínez-Ramos, M.

    2012-01-01

    1. Persistent variation in growth rate between individual plants can have strong effects on population dynamics as fast growers reach the reproductive size at an earlier age and thus potentially contribute more to population growth than slow growers. In tropical forests, such persistent growth

  15. Quantitative Approach to Collaborative Learning: Performance Prediction, Individual Assessment, and Group Composition

    Science.gov (United States)

    Cen, Ling; Ruta, Dymitr; Powell, Leigh; Hirsch, Benjamin; Ng, Jason

    2016-01-01

    The benefits of collaborative learning, although widely reported, lack the quantitative rigor and detailed insight into the dynamics of interactions within the group, while individual contributions and their impacts on group members and their collaborative work remain hidden behind joint group assessment. To bridge this gap we intend to address…

  16. The Effect of Group Composition on Individual Student Performance in an Introductory Economics Course

    Science.gov (United States)

    Moore, Robert L.

    2011-01-01

    What is the best way to allocate students to small teams in those economics courses that rely on small group work to enhance individual student learning? While experts in collaborative learning provide many suggestions, little empirical work has been done. This article begins to fill the gap. It examines whether a variety of characteristics of the…

  17. THE DYNAMIC MODEL FOR CONTROL OF STUDENT’S LEARNING INDIVIDUAL TRAJECTORY

    Directory of Open Access Journals (Sweden)

    A. A. Mitsel

    2015-01-01

    Full Text Available In connection with the transition of the educational system to a competence-oriented approach, the problem of learning outcomes assessment and creating an individual learning trajectory of a student has become relevant. Its solution requires the application of modern information technologies. The third generation of Federal state educational standards of higher professional education (FSES HPE defines the requirements for the results of Mastering the basic educational programs (BEP. According to FSES HPE up to 50% of subjects have a variable character, i.e. depend on the choice of a student. It significantly influences on the results of developing various competencies. The problem of forming student’s learning trajectory is analyzed in general and the choice of an individual direction was studied in details. Various methods, models and algorithms of the student’s individual learning trajectory formation were described. The analysis of the model of educational process organization in terms of individual approach makes it possible to develop a decision support system (DSS. DSS is a set of interrelated programs and data used for analysis of situation, development of alternative solutions and selection of the most acceptable alternative. DSSs are often used when building individual learning path, because this task can be considered as a discrete multi-criteria problem, creating a significant burden on the decision maker. A new method of controlling the learning trajectory has been developed. The article discusses problem statement and solution of determining student’s optimal individual educational trajectory as a dynamic model of learning trajectory control, which uses score assessment to construct a sequence of studied subjects. A new model of management learning trajectory is based on dynamic models for tracking the reference trajectory. The task can be converted to an equivalent model of linear programming, for which a reliable solution

  18. Integrating Biodiversity into Biosphere-Atmosphere Interactions Using Individual-Based Models (IBM)

    Science.gov (United States)

    Wang, B.; Shugart, H. H., Jr.; Lerdau, M.

    2017-12-01

    A key component regulating complex, nonlinear, and dynamic biosphere-atmosphere interactions is the inherent diversity of biological systems. The model frameworks currently widely used, i.e., Plant Functional Type models) do not even begin to capture the metabolic and taxonomic diversity found in many terrestrial systems. We propose that a transition from PFT-based to individual-based modeling approaches (hereafter referred to as IBM) is essential for integrating biodiversity into research on biosphere-atmosphere interactions. The proposal emerges from our studying the interactions of forests with atmospheric processes in the context of climate change using an individual-based forest volatile organic compounds model, UVAFME-VOC. This individual-based model can explicitly simulate VOC emissions based on an explicit modelling of forest dynamics by computing the growth, death, and regeneration of each individual tree of different species and their competition for light, moisture, and nutrient, from which system-level VOC emissions are simulated by explicitly computing and summing up each individual's emissions. We found that elevated O3 significantly altered the forest dynamics by favoring species that are O3-resistant, which, meanwhile, are producers of isoprene. Such compositional changes, on the one hand, resulted in unsuppressed forest productivity and carbon stock because of the compensation by O3-resistant species. On the other hand, with more isoprene produced arising from increased producers, a possible positive feedback loop between tropospheric O3 and forest thereby emerged. We also found that climate warming will not always stimulate isoprene emissions because warming simultaneously reduces isoprene emissions by causing a decline in the abundance of isoprene-emitting species. These results suggest that species diversity is of great significance and that individual-based modelling strategies should be applied in studying biosphere-atmosphere interactions.

  19. Understanding the structure of skill through a detailed analysis of Individuals' performance on the Space Fortress game.

    Science.gov (United States)

    Towne, Tyler J; Boot, Walter R; Ericsson, K Anders

    2016-09-01

    In this paper we describe a novel approach to the study of individual differences in acquired skilled performance in complex laboratory tasks based on an extension of the methodology of the expert-performance approach (Ericsson & Smith, 1991) to shorter periods of training and practice. In contrast to more traditional approaches that study the average performance of groups of participants, we explored detailed behavioral changes for individual participants across their development on the Space Fortress game. We focused on dramatic individual differences in learning and skill acquisition at the individual level by analyzing the archival game data of several interesting players to uncover the specific structure of their acquired skill. Our analysis revealed that even after maximal values for game-generated subscores were reached, the most skilled participant's behaviors such as his flight path, missile firing, and mine handling continued to be refined and improved (Participant 17 from Boot et al., 2010). We contrasted this participant's behavior with the behavior of several other participants and found striking differences in the structure of their performance, which calls into question the appropriateness of averaging their data. For example, some participants engaged in different control strategies such as "world wrapping" or maintaining a finely-tuned circular flight path around the fortress (in contrast to Participant 17's angular flight path). In light of these differences, we raise fundamental questions about how skill acquisition for individual participants should be studied and described. Our data suggest that a detailed analysis of individuals' data is an essential step for generating a general theory of skill acquisition that explains improvement at the group and individual levels. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Characteristics and Diffusion Model of the Individual Knowledge in the WeChat Mode

    Directory of Open Access Journals (Sweden)

    Zhang Lingzhi

    2017-12-01

    Full Text Available [Purpose/significance] According to the model of the individual knowledge diffusion, we conduct a behavior research and analyze the characteristics of that based on WeChat which is the most popular communication platform in China.[Method/process] By analyzing the methods of the diffusion on WeChat, we analyzed the characteristics of the individual knowledge diffusion. [Result/conclusion]The characteristics of the individual knowledge diffusion include real-time, short-term, speciality, friendship and transmission.