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Sample records for task based exposure

  1. Field evaluation of measuring indoor noise exposure in workplace with task-based active RFID technology.

    PubMed

    Huang, Fu-Chuan; Shih, Tung-Sheng; Lee, Jiunn-Fwu; Wang, Te-Shun; Wang, Peng-Yau

    2010-03-01

    This paper describes the research using RFEMS (Radio Frequency Identification Exposure Monitoring System), which is designed by applying the task-based active RFID (radio frequency identification) technology, to measure the indoor noise exposure dose in a workplace. The RFEMS and sound level meter are mounted on the vests of eight workers to carry out on-site field test by monitoring the time activity pattern (TAP), and the noise dose level exposed by the workers. The data are recorded and instantaneously transmitted to a computer to be saved in the server and later compared to those obtained using the standard method. The results that have a 0.909 correlation coefficient (R(2)), and 1.64% average measure error confirm the accuracy of using RFEMS for monitoring TAP. Additionally, the combined use of RFEMS and sound level meter leads to the development of a semi noise dosimetry (SND), a real-time electronic indirect noise dosimetry (REIND), and an equivalent electronic recording indirect noise dosimetry (EEIND). The results obtained using these three devices are well correlated with the results monitored by using a PND (personal noise dosimetry) with correlation coefficients (R(2)) of 0.915, 0.779 and 0.873, respectively. The errors of noise dose expressed in TWA (time weight average) for these three methods are 0.81, 1.57 and 1.23 dBA, respectively; they are well within the general errors of the average dosimetries. These observations indicate that the RFEMS developed in this research is applicable for conducting task-based measurements of indoor noise. It uses a relatively inexpensive sound level meter to measure the noise exposure doses that are comparable to those obtained with a standard dosimetry in addition to monitoring the worker's time activity pattern. The findings will assist in studying the source of long-term noise exposed by workers, and hence this devise is a valuable tool for tracing and monitoring long-term noise exposure with reduced manpower

  2. Task based exposure assessment in ergonomic epidemiology: a study of upper arm elevation in the jobs of machinists, car mechanics, and house painters

    PubMed Central

    Svendsen, S; Mathiassen, S; Bonde, J

    2005-01-01

    Aims: To explore the precision of task based estimates of upper arm elevation in three occupational groups, compared to direct measurements of job exposure. Methods: Male machinists (n = 26), car mechanics (n = 23), and house painters (n = 23) were studied. Whole day recordings of upper arm elevation were obtained for four consecutive working days, and associated task information was collected in diaries. For each individual, task based estimates of job exposure were calculated by weighting task exposures from a collective database by task proportions according to the diaries. These estimates were validated against directly measured job exposures using linear regression. The performance of the task based approach was expressed through the gain in precision of occupational group mean exposures that could be obtained by adding subjects with task based estimates to a group of subjects with measured job exposures in a "validation" design. Results: In all three occupations, tasks differed in mean exposure, and task proportions varied between individuals. Task based estimation proved inefficient, with squared correlation coefficients only occasionally exceeding 0.2 for the relation between task based and measured job exposures. Consequently, it was not possible to substantially improve the precision of an estimated group mean by including subjects whose job exposures were based on task information. Conclusions: Task based estimates of mechanical job exposure can be very imprecise, and only marginally better than estimates based on occupation. It is recommended that investigators in ergonomic epidemiology consider the prospects of task based exposure assessment carefully before placing resources at obtaining task information. Strategies disregarding tasks may be preferable in many cases. PMID:15613604

  3. Task-based assessment of occupational vibration and noise exposures in forestry workers.

    PubMed

    Neitzel, Richard; Yost, Michael

    2002-01-01

    Forty-two noise exposures and 164 whole-body (WBV) and hand-arm (HAV) vibration exposures were collected from 43 forestry workers in six trades employed by two forestry companies. Data were collected on 10 days over 8 weeks during various felling, logging, and log handling operations. Up to 5 volunteers were monitored for noise and vibration daily using datalogging noise dosimeters, which provided daily time-weighted averages (TWAs) and 1-min averages; and a precision sound level meter equipped to measure human vibration, which provided triaxial HAV and WBV event-weighted averages (AEQS). Workers completed a short questionnaire throughout the workday detailing the timing and number of tasks performed and equipment used. Substantial overexposures to noise and vibration were seen; for example, 60% of Occupational Safety and Health Administration (OSHA) TWAs and 83% of National Institute for Occupational Safety and Health (NIOSH) noise TWAs exceeded 85 dBA, 33-53% of the axis-specific HAV AEQS exceeded the 8-hour American Conference of Governmental Industrial Hygienists' HAV threshold limit value, and 34% of all summary weighted WBV AEQS exceeded the Commission of the European Communities' 8-hour exposure limit. The mean for 99 WBV summary weighted AEQ was 3.53 +/- 7.12 m/sec2, whereas the mean for 65 HAV summary weighted AEQ was 5.45 +/- 5.25 m/sec2. The mean OSHA TWA was 86.1 +/- 6.2 dBA, whereas the mean NIOSH TWA was 90.2 +/- 5.1 dBA. The task and tool with the highest exposure levels were unbelling chokers on landings and chain saws (noise), log processing and frontend loaders (WBV), and notching stumps and chain saws (HAV). An internal validation substudy indicated excellent agreement between worker-reported and researcher-documented tasks and tools.

  4. Task exposures in an office environment: a comparison of methods.

    PubMed

    Van Eerd, Dwayne; Hogg-Johnson, Sheilah; Mazumder, Anjali; Cole, Donald; Wells, Richard; Moore, Anne

    2009-10-01

    Task-related factors such as frequency and duration are associated with musculoskeletal disorders in office settings. The primary objective was to compare various task recording methods as measures of exposure in an office workplace. A total of 41 workers from different jobs were recruited from a large urban newspaper (71% female, mean age 41 years SD 9.6). Questionnaire, task diaries, direct observation and video methods were used to record tasks. A common set of task codes was used across methods. Different estimates of task duration, number of tasks and task transitions arose from the different methods. Self-report methods did not consistently result in longer task duration estimates. Methodological issues could explain some of the differences in estimates seen between methods observed. It was concluded that different task recording methods result in different estimates of exposure likely due to different exposure constructs. This work addresses issues of exposure measurement in office environments. It is of relevance to ergonomists/researchers interested in how to best assess the risk of injury among office workers. The paper discusses the trade-offs between precision, accuracy and burden in the collection of computer task-based exposure measures and different underlying constructs captures in each method.

  5. PRN 2000-7: Non-Dietary Exposure Task Force

    EPA Pesticide Factsheets

    This PR Notice announces an industry-wide task force to jointly develop residential indoor exposure data for pesticides containing one or more of the active ingredients synthetic pyrethroids, pyrethrum and synergists.

  6. Hexavalent chromium exposure and control in welding tasks.

    PubMed

    Meeker, John D; Susi, Pam; Flynn, Michael R

    2010-11-01

    Studies of exposure to the lung carcinogen hexavalent chromium (CrVI) from welding tasks are limited, especially within the construction industry where overexposure may be common. In addition, despite the OSHA requirement that the use of engineering controls such as local exhaust ventilation (LEV) first be considered before relying on other strategies to reduce worker exposure to CrVI, data on the effectiveness of LEV to reduce CrVI exposures from welding are lacking. The goal of the present study was to characterize breathing zone air concentrations of CrVI during welding tasks and primary contributing factors in four datasets: (1) OSHA compliance data; (2) a publicly available database from The Welding Institute (TWI); (3) field survey data of construction welders collected by the Center for Construction Research and Training (CPWR); and (4) controlled welding trials conducted by CPWR to assess the effectiveness of a portable LEV unit to reduce CrVI exposure. In the OSHA (n = 181) and TWI (n = 124) datasets, which included very few samples from the construction industry, the OSHA permissible exposure level (PEL) for CrVI (5 μg/m(3)) was exceeded in 9% and 13% of samples, respectively. CrVI concentrations measured in the CPWR field surveys (n = 43) were considerably higher, and 25% of samples exceeded the PEL. In the TWI and CPWR datasets, base metal, welding process, and LEV use were important predictors of CrVI concentrations. Only weak-to-moderate correlations were found between total particulate matter and CrVI, suggesting that total particulate matter concentrations are not a good surrogate for CrVI exposure in retrospective studies. Finally, in the controlled welding trials, LEV reduced median CrVI concentrations by 68% (p = 0.02). In conclusion, overexposure to CrVI in stainless steel welding is likely widespread, especially in certain operations such as shielded metal arc welding, which is commonly used in construction. However, exposure could be

  7. Benefits of Stimulus Exposure: Developmental Learning Independent of Task Performance

    PubMed Central

    Green, David B.; Ohlemacher, Jocelyn; Rosen, Merri J.

    2016-01-01

    Perceptual learning (training-induced performance improvement) can be elicited by task-irrelevant stimulus exposure in humans. In contrast, task-irrelevant stimulus exposure in animals typically disrupts perception in juveniles while causing little to no effect in adults. This may be due to the extent of exposure, which is brief in humans while chronic in animals. Here we assessed the effects of short bouts of passive stimulus exposure on learning during development in gerbils, compared with non-passive stimulus exposure (i.e., during testing). We used prepulse inhibition of the acoustic startle response, a method that can be applied at any age, to measure gap detection thresholds across four age groups, spanning development. First, we showed that both gap detection thresholds and gap detection learning across sessions displayed a long developmental trajectory, improving throughout the juvenile period. Additionally, we demonstrated larger within- and across-animal performance variability in younger animals. These results are generally consistent with results in humans, where there are extended developmental trajectories for both the perception of temporally-varying signals, and the effects of perceptual training, as well as increased variability and poorer performance consistency in children. We then chose an age (mid-juveniles) that displayed clear learning over sessions in order to assess effects of brief passive stimulus exposure on this learning. We compared learning in mid-juveniles exposed to either gap detection testing (gaps paired with startles) or equivalent gap exposure without testing (gaps alone) for three sessions. Learning was equivalent in both these groups and better than both naïve age-matched animals and controls receiving no gap exposure but only startle testing. Thus, short bouts of exposure to gaps independent of task performance is sufficient to induce learning at this age, and is as effective as gap detection testing. PMID:27378837

  8. Combined analysis of job and task benzene air exposures among workers at four US refinery operations.

    PubMed

    Burns, Amanda; Shin, Jennifer Mi; Unice, Ken M; Gaffney, Shannon H; Kreider, Marisa L; Gelatt, Richard H; Panko, Julie M

    2017-03-01

    Workplace air samples analyzed for benzene at four US refineries from 1976 to 2007 were pooled into a single dataset to characterize similarities and differences between job titles, tasks and refineries, and to provide a robust dataset for exposure reconstruction. Approximately 12,000 non-task (>180 min) personal samples associated with 50 job titles and 4000 task (<180 min) samples characterizing 24 tasks were evaluated. Personal air sample data from four individual refineries were pooled based on a number of factors including (1) the consistent sampling approach used by refinery industrial hygienists over time, (2) the use of similar exposure controls, (3) the comparability of benzene content of process streams and end products, (4) the ability to assign uniform job titles and task codes across all four refineries, and (5) our analysis of variance (ANOVA) of the distribution of benzene air concentrations for select jobs/tasks across all four refineries. The jobs and tasks most frequently sampled included those with highest potential contact with refinery product streams containing benzene, which reflected the targeted sampling approach utilized by the facility industrial hygienists. Task and non-task data were analyzed to identify and account for significant differences within job-area, task-job, and task-area categories. This analysis demonstrated that in general, areas with benzene containing process streams were associated with greater benzene air concentrations compared to areas with process streams containing little to no benzene. For several job titles and tasks analyzed, there was a statistically significant decrease in benzene air concentration after 1990. This study provides a job and task-focused analysis of occupational exposure to benzene during refinery operations, and it should be useful for reconstructing refinery workers' exposures to benzene over the past 30 years.

  9. Task-Based Writing Instruction

    ERIC Educational Resources Information Center

    Bantis, Alexandros

    2010-01-01

    The purpose of this study was to investigate the impact of task-based writing instruction, a communicative language-teaching method, on second language acquisition and differentiation of instruction for English language learners during the independent work time instructional component of the Open Court Reading program. Through student-teacher…

  10. Mentalization of complex emotions in borderline personality disorder: The impact of parenting and exposure to trauma on the performance in a novel cartoon-based task.

    PubMed

    Brüne, Martin; Walden, Sarah; Edel, Marc-Andreas; Dimaggio, Giancarlo

    2016-01-01

    Borderline personality disorder (BPD) is characterized by a range of interpersonal difficulties, which are, in part, related to adverse experiences during childhood. Unresponsive parenting and traumatization may cause functional impairment of mentalization, i.e. the ability to reflect upon own and others' mental states. However, the relationship of poor parenting, trauma and mentalization in BPD has not exhaustively been studied. Thirty patients diagnosed with BPD and 30 matched control subjects were asked to sequence a novel cartoon-based mentalization task involving complex emotions such as jealousy, shame, guilt etc. In addition, they were required to reason about cognitive and affective mental states of the cartoon characters. The quality of parental care was assessed using a self-report measure for recalled parental rearing style, and childhood trauma was measured in retrospect using the Childhood Trauma Questionnaire. Patients with BPD performed more poorly in all aspects of the cartoon task. Mentalizing skills, particularly relating to affective mental states, were uniquely associated with the quality of recalled parental care and childhood trauma. Together, the quality of parental care and the experience of childhood trauma negatively impact on mentalization in BPD, even in an experimental "offline" task.

  11. Pilot task-based assessment of noise levels among firefighters

    PubMed Central

    Neitzel, RL; Hong, O; Quinlan, P; Hulea, R

    2012-01-01

    PURPOSE Over one million American firefighters are routinely exposed to various occupational hazards agents. While efforts have been made to identify and reduce some causes of injuries and illnesses among firefighters, relatively little has been done to evaluate and understand occupational noise exposures in this group. The purpose of this pilot study was to apply a task-based noise exposure assessment methodology to firefighting operations to evaluate potential noise exposure sources, and to use collected task-based noise levels to create noise exposure estimates for evaluation of risk of noise-induced hearing loss by comparison to the 8-hr and 24-hr recommended exposure limits (RELs) for noise of 85 and 80.3 dBA, respectively. METHODS Task-based noise exposures (n=100 measurements) were measured in three different fire departments (a rural department in Southeast Michigan and suburban and urban departments in Northern California). These levels were then combined with time-at-task information collected from firefighters to estimate 8-hr noise exposures for the rural and suburban fire departments (n=6 estimates for each department). Data from 24-hr dosimetry measurements and crude self-reported activity categories from the urban fire department (n=4 measurements) were used to create 24-hr exposure estimates to evaluate the bias associated with the task-based estimates. RESULTS Task-based noise levels were found to range from 82–109 dBA, with the highest levels resulting from use of saws and pneumatic chisels. Some short (e.g., 30 min) sequences of common tasks were found to result in nearly an entire allowable daily exposure. The majority of estimated 8-hr and 24-hr exposures exceeded the relevant recommended exposure limit. Predicted 24-hr exposures showed substantial imprecision in some cases, suggesting the need for increased task specificity. CONCLUSIONS The results indicate potential for overexposure to noise from a variety of firefighting tasks and

  12. PRN 2007-3: The Agricultural Handlers Exposure Task Force, L.L.C

    EPA Pesticide Factsheets

    This PR Notice discusses the Agricultural Handlers Exposure Task Force, an industry-wide task force formed to develop mixer, loader, and applicator exposure data for pesticides used in agricultural settings. It includes contacts for more information.

  13. Cosmetology: Task Analyses. Competency-Based Education.

    ERIC Educational Resources Information Center

    Henrico County Public Schools, Glen Allen, VA. Virginia Vocational Curriculum Center.

    These task analyses are designed to be used in combination with the "Trade and Industrial Education Service Area Resource" in order to implement competency-based education in the cosmetology program in Virginia. The task analysis document contains the task inventory, suggested task sequence lists, and content outlines for the secondary…

  14. In-Session Exposure Tasks and Therapeutic Alliance across the Treatment of Childhood Anxiety Disorders

    ERIC Educational Resources Information Center

    Kendall, Philip C.; Comer, Jonathan S.; Marker, Craig D.; Creed, Torrey A.; Puliafico, Anthony C.; Hughes, Alicia A.; Martin, Erin D.; Suveg, Cynthia; Hudson, Jennifer

    2009-01-01

    The study examined the shape of therapeutic alliance using latent growth curve modeling and data from multiple informants (therapist, child, mother, father). Children (n = 86) with anxiety disorders were randomized to family-based cognitive-behavioral treatment (FCBT; N = 47) with exposure tasks or to family education, support, and attention…

  15. PRN 94-9: Announcing the Formation of Two Industry-Wide Task Forces: Agricultural Reentry Task Force and Outdoor Residential Exposure Task Force

    EPA Pesticide Factsheets

    This Notice announces two industry-wide Task Forces being formed in response to generic exposure data requirements. It contains EPA's policy on a registrant's options for, and responsibilities when joining Task Force as a way to satisfy data requirements.

  16. Task-Based Instruction Using the Internet.

    ERIC Educational Resources Information Center

    Tumposky, Nancy Rennau

    This paper describes the design and implementation of an English as a Foreign Language (EFL) task-based module consistent with Skehan's information processing model of second language acquisition (1998) and with the framework for task design elaborated by Willis (1996), using the Internet as a primary source of language input. In settings where…

  17. Safety-Seeking and Coping Behavior during Exposure Tasks with Anxious Youth

    ERIC Educational Resources Information Center

    Hedtke, Kristina A.; Kendall, Philip C.; Tiwari, Shilpee

    2009-01-01

    This study examined child behavior during exposure tasks and characteristics of the exposure tasks as related to outcomes when treating anxious youth. Participants (aged 7-13) were 87 anxiety-disordered children (37 girls; 50 boys) and their parents (84 mothers; 70 fathers) who completed a 16-session cognitive-behavioral therapy. Videotapes of…

  18. Dose optimization for different medical imaging tasks from exposure index, exposure control factor, and MAS in digital radiography.

    PubMed

    Zhang, Menglong; Zhao, Bin; Wang, Yaying; Chen, Weixia; Hou, Lixia

    2012-09-01

    In radiographic examination, not all medical imaging tasks require the same level of image quality or diagnostic information. Criteria should be established for different imaging tasks to avoid excessive doses where there is no clear net benefit in the diagnosis or the image quality. An exposure index provided by manufacturers would be a useful tool for this purpose. This study aims to establish an optimum exposure index to be used as a guideline for clinical imaging tasks to minimize radiation exposure for chest digital radiography. A three-level classification of image quality (high, medium, and low) for chest imaging tasks was carried out. An anthropomorphic phantom was employed to establish minimum exposure index and exposure (mAs) for clinical imaging task type I (corresponding to high image quality). The exposures of medium and low quality images derived from it. Thirty patients were exposed consecutively with these optimized exposure factors, and clinical tasks were considered, while another 30 patients were exposed with the exposure factors routinely used in practice. Image quality was assessed objectively by a consensus panel. The optimized exposure provided a significant reduction of the mean exposure index from 1,556 to 1,207 (p < 0.0001) and mean patient's entrance surface dose from 0.168 mGy to 0.092 mGy (p < 0.0001). The results show that a clinical-task-determined radiographic procedure is more conducive to radiation protection of patients. In this study, the posteroanterior chest imaging examination was chosen as an example. This procedure can also apply to other body parts and views.

  19. Task based synthesis of serial manipulators

    PubMed Central

    Patel, Sarosh; Sobh, Tarek

    2015-01-01

    Computing the optimal geometric structure of manipulators is one of the most intricate problems in contemporary robot kinematics. Robotic manipulators are designed and built to perform certain predetermined tasks. There is a very close relationship between the structure of the manipulator and its kinematic performance. It is therefore important to incorporate such task requirements during the design and synthesis of the robotic manipulators. Such task requirements and performance constraints can be specified in terms of the required end-effector positions, orientations and velocities along the task trajectory. In this work, we present a comprehensive method to develop the optimal geometric structure (DH parameters) of a non-redundant six degree of freedom serial manipulator from task descriptions. In this work we define, develop and test a methodology to design optimal manipulator configurations based on task descriptions. This methodology is devised to investigate all possible manipulator configurations that can satisfy the task performance requirements under imposed joint constraints. Out of all the possible structures, the structures that can reach all the task points with the required orientations are selected. Next, these candidate structures are tested to see whether they can attain end-effector velocities in arbitrary directions within the user defined joint constraints, so that they can deliver the best kinematic performance. Additionally least power consuming configurations are also identified. PMID:26257946

  20. TASK 2.5.5 NATURAL EXPOSURE TESTING IN CALIFORNIA

    SciTech Connect

    Miller, William A; Cheng, Mengdawn; New, Joshua Ryan; Ronnen, Levinson; Akbari, Hashem; Berhahl, Paul

    2010-03-01

    membranes and the roof coatings. Airborne contaminants and biomass were also detected on the painted metal roofs; however, the loss of solar reflectance was less than 5% for the painted metal roofs. The chemistry of the PVDF paint resin system uses similar organic film bonding to that responsible for Teflon , making it extremely chemical resistant and dirt shedding. Miller and Rudolph (2003) found the PVDF painted metals maintained solar reflectance even after 30 years of climatic exposure. Therefore the reduction of roof reflectance is closely related to the composition of the roof and to the chemical profile of the contaminants soiling the roof. Contaminants collected from samples of roof products exposed at seven California weathering sites were analyzed for elements and carbons to characterize the chemical profile of the particles soiling each roof sample and to identify those elements that degrade or enhance solar reflectance. The losses in solar reflectance varied from site to site and also varied at a give site based on the color of the coupon. The least drop in reflectance was observed in the alpine climate of McArthur while the largest drop occurred in sites near urban development. Light color samples were soiled after just one year of exposure. The darker color coupons did not show the same seasonal variations in solar reflectance as observed for the lighter colors. However, after an additional year of exposure the samples at all sites regained most of their solar reflectance due to rain and/or wind washing. The loss of reflectance appears cyclical with the onset of seasons having more rainfall. Solar reflectance of the cool pigmented coupons always exceeded that of the conventional pigmented coupons. Climatic soiling did not cause the cool pigmented roof coupons to lose any more solar reflectance than their conventional pigmented counterparts. The effect of roof slope appears to have more of an effect on lighter color roofs whose solar reflectance exceeds at

  1. Task Based Language Teaching: Development of CALL

    ERIC Educational Resources Information Center

    Anwar, Khoirul; Arifani, Yudhi

    2016-01-01

    The dominant complexities of English teaching in Indonesia are about limited development of teaching methods and materials which still cannot optimally reflect students' needs (in particular of how to acquire knowledge and select the most effective learning models). This research is to develop materials with complete task-based activities by using…

  2. Tool and Task Analysis Guide for Vocational Welding (150 Tasks). Performance Based Vocational Education.

    ERIC Educational Resources Information Center

    John H. Hinds Area Vocational School, Elwood, IN.

    This book contains a task inventory, a task analysis of 150 tasks from that inventory, and a tool list for performance-based welding courses in the state of Indiana. The task inventory and tool list reflect 28 job titles found in Indiana. In the first part of the guide, tasks are listed by these domains: carbon-arc, electron beam, G.M.A.W., gas…

  3. Acute effects of 50 Hz magnetic field exposure on human visual task and cardiovascular performance

    SciTech Connect

    Whittington, C.J.; Podd, J.V.; Rapley, B.R.

    1996-05-01

    One hundred subjects, males and females with ages ranging between 18 and 48 years, were studied under both field-exposed and sham-exposed conditions. A 50 Hz, 100 {micro}T magnetic field (MF) was used. To examine the effect of field exposure on performance, a two-alternative, forced-choice, duration-discrimination task with three levels of difficulty was used. The subject`s task was to decide which of two sequentially presented light flashes had the longer duration. The standard duration was 50 ms, and the alternative durations were 65, 100, or 125 ms. Both reaction time and percentage of correct responses were recorded for each subject. MF and sham exposure were for 9 min each. Blood pressure and heart rate were also measured before and following MF exposure and sham-exposure trials. The study was performed double blind, with the exposure order counterbalanced. Compared to sham exposure, MF exposure significantly decreased reaction time on the hardest level of the performance task. MF exposure did not reliably affect percentage correct or cardiovascular performance. It was demonstrated that a relatively high level of statistical power was the basis for the observed MF effect, and the need to pay closer attention to power levels in future research is discussed.

  4. Binding Task-Based Language Teaching and Task-Based Language Testing: A Survey into EFL Teachers and Learners' Views of Task-Based Approach

    ERIC Educational Resources Information Center

    Panahi, Ali

    2012-01-01

    In most settings, task-based language teaching and testing have been dissociated from each other. That is why this study came to rethink of the learners' views towards awareness and implementation of task-based language teaching through IELTS listening tasks. To these objectives, after sketching instrumentation, the learners were divided into…

  5. Perceptual learning of basic visual features remains task specific with Training-Plus-Exposure (TPE) training.

    PubMed

    Cong, Lin-Juan; Wang, Ru-Jie; Yu, Cong; Zhang, Jun-Yun

    2016-01-01

    Visual perceptual learning is known to be specific to the trained retinal location, feature, and task. However, location and feature specificity can be eliminated by double-training or TPE training protocols, in which observers receive additional exposure to the transfer location or feature dimension via an irrelevant task besides the primary learning task Here we tested whether these new training protocols could even make learning transfer across different tasks involving discrimination of basic visual features (e.g., orientation and contrast). Observers practiced a near-threshold orientation (or contrast) discrimination task. Following a TPE training protocol, they also received exposure to the transfer task via performing suprathreshold contrast (or orientation) discrimination in alternating blocks of trials in the same sessions. The results showed no evidence for significant learning transfer to the untrained near-threshold contrast (or orientation) discrimination task after discounting the pretest effects and the suprathreshold practice effects. These results thus do not support a hypothetical task-independent component in perceptual learning of basic visual features. They also set the boundary of the new training protocols in their capability to enable learning transfer.

  6. Sex Differences in Task Distribution and Task Exposures among Danish House Painters: An Observational Study Combining Questionnaire Data with Biomechanical Measurements

    PubMed Central

    Heilskov-Hansen, Thomas; Wulff Svendsen, Susanne; Frølund Thomsen, Jane; Mikkelsen, Sigurd; Hansson, Gert-Åke

    2014-01-01

    Objectives Sex differences in occupational biomechanical exposures may be part of the explanation why musculoskeletal complaints and disorders tend to be more common among women than among men. We aimed to determine possible sex differences in task distribution and task-specific postures and movements of the upper extremities among Danish house painters, and to establish sex-specific task exposure matrices. Methods To obtain task distributions, we sent out a questionnaire to all members of the Painters' Union in Denmark (N = 9364), of whom 53% responded. Respondents reported their task distributions in a typical week. To obtain task exposures, postures and movements were measured in 25 male and 25 female house painters for one whole working day per person. We used goniometers on the wrists, and inclinometers on the forehead and the upper arms. Participants filled in a logbook allowing task-specific exposures to be identified. Percentiles and % time with non-neutral postures were used to characterise postures. Velocity, range of motion, repetitiveness, and variation were used as measures of movement. Cochran-Mantel-Haenszel statistics and unpaired double-sided t-tests with post-hoc Bonferroni correction were used to evaluate sex differences. Results Statistically significant (p<0.05) sex differences were revealed in task proportions, but the proportions differed by less than 4%. For task exposures, no statistically significant sex differences were found. Conclusions Only minor sex differences were found in task distribution and task exposures regarding postures and movements among Danish house painters. Sex-specific task exposure matrices were established. PMID:25365301

  7. Characterizing Task-Based OpenMP Programs

    PubMed Central

    Muddukrishna, Ananya; Jonsson, Peter A.; Brorsson, Mats

    2015-01-01

    Programmers struggle to understand performance of task-based OpenMP programs since profiling tools only report thread-based performance. Performance tuning also requires task-based performance in order to balance per-task memory hierarchy utilization against exposed task parallelism. We provide a cost-effective method to extract detailed task-based performance information from OpenMP programs. We demonstrate the utility of our method by quickly diagnosing performance problems and characterizing exposed task parallelism and per-task instruction profiles of benchmarks in the widely-used Barcelona OpenMP Tasks Suite. Programmers can tune performance faster and understand performance tradeoffs more effectively than existing tools by using our method to characterize task-based performance. PMID:25860023

  8. Bilingual Children's Acquisition of English Verb Morphology: Effects of Language Exposure, Structure Complexity, and Task Type

    ERIC Educational Resources Information Center

    Paradis, Johanne

    2010-01-01

    This study investigated whether bilingual-monolingual differences would be apparent in school-age children's use and knowledge of English verb morphology and whether differences would be influenced by amount of exposure to English, complexity of the morphological structure, or the type of task given. French-English bilinguals (mean age = 6;10)…

  9. Developing a driving simulator based functional object detection task.

    PubMed

    Goodenough, Richard R; Brooks, Johnell O; Crisler, Matthew C; Rosopa, Patrick J

    2012-10-01

    The purpose of this study was to validate a driving simulator-based tool for assessing functional visual scanning while driving (Goodenough, 2010) by replicating a previous study and assessing whether the results of the task are moderated by strategic decisions regarding task prioritization. Participants completed a functional object detection task that includes a peripheral target detection task and a central braking response task. Results indicated that the simulator task can identify differences in older and younger participants' abilities to functionally scan the driving environment and these differences appear unaffected by prioritizing either the scanning or braking task. Implications are discussed.

  10. Integration of Task-Based Approaches in a TESOL Course

    ERIC Educational Resources Information Center

    Chien, Chin-Wen

    2014-01-01

    Under task-based language teaching (TBLT), language learners engage in purposeful, problem-oriented, and outcome-driven tasks that are comparable to real-world activities. This qualitative case study discusses the integration of a task-based approach into a TESOL course in a language teacher education program in Taiwan with regard to 39…

  11. A Blended Learning Study on Implementing Video Recorded Speaking Tasks in Task-Based Classroom Instruction

    ERIC Educational Resources Information Center

    Kirkgoz, Yasemin

    2011-01-01

    This study investigates designing and implementing a speaking course in which face-to-face instruction informed by the principles of Task-Based Learning is blended with the use of technology, the video, for the first-year student teachers of English in Turkish higher education. The study consisted of three hours of task-based classroom…

  12. Building tasks from verbal instructions: an EEG study on practice trial exposure and task structure complexity during novel sequences of behavior.

    PubMed

    Roberts, Gareth; Jones, Timothy W; Davis, Elizabeth A; Ly, Trang T; Anderson, Mike

    2014-12-01

    Configuring the mind to perform a novel task is an effortful process and one that is related to differences in general intelligence. Previous research has suggested that when participants are given instructions for a future task, representations of the rules contained in the instructions can influence subsequent behavior, even when the rules are not necessary to perform the upcoming task. One hypothesis for the continued activation of rule representations suggests that the practice trials participants perform before the experimental trials may instantiate the unnecessary task rules into participants' mental model of the task (i.e., the task space). To test this hypothesis, EEGs were recorded as participants (N = 66) completed a multirule task designed to contrast the effects of increasing task structure complexity and practice trial exposure. The results showed that, as was predicted, performance is significantly poorer when more task rules are specified in the task instructions. Practice trials with the extra rule did not affect task performance, indicating that an unacted verbal instruction is sufficient to incorporate the rule into participants' mental model of the task. The EEG results showed that instruction complexity was linked to a phasic increase in frontal theta synchronization but reduced posterior alpha and beta desynchronization. These changes in synchronization occurred during a time period of low intertrial phase coherence and suggest that participants were "checking the task rules" amidst a trial. This transient neural activity may reflect compensatory mechanisms for dealing with increased mind-wandering that is more likely to occur in complex tasks.

  13. The influence of task and location on solvent exposures in a printing plant.

    PubMed

    Hansen, D J; Whitehead, L W

    1988-05-01

    A work measurement technique was used to monitor the activities of seven printing press operators. Repeated observations were made to learn workers' tasks and workers' locations in the plant, and a photoionization detector was used to measure the instantaneous solvent concentration in each worker's breathing zone. Location data, analyzed using a computer aided design system, did not show any indication that there were high or low exposure areas. Regression, however, showed that a significant amount of variability in a worker's exposures was accounted for by the number of times the worker performed a certain "hazardous task" (r2 = 0.57). The results indicate that it may be possible to simplify industrial hygiene sampling strategies by using work measurement data, such as time study or work sampling, to identify maximum risk employees.

  14. Agricultural Production: Task Analyses. Competency-Based Education.

    ERIC Educational Resources Information Center

    Henrico County Public Schools, Glen Allen, VA. Virginia Vocational Curriculum Center.

    This task analysis guide is intended to help teachers and administrators develop instructional materials and implement competency-based education in the agricultural production program. Section 1 contains a validated task inventory for agricultural production. Tasks are divided into 10 duty areas: orienting the student to agricultural production,…

  15. Dental Aide: Task Analyses. Competency-Based Education.

    ERIC Educational Resources Information Center

    Newport News Public Schools, VA.

    This task analysis guide is intended to help teachers and administrators develop instructional materials and implement competency-based education in the dental aide program. Section 1 contains a validated task inventory for dental aide. For each task, applicable information pertaining to performance and enabling objectives, criterion-referenced…

  16. Using Goal Setting and Task Analysis to Enhance Task-Based Language Learning and Teaching

    ERIC Educational Resources Information Center

    Rubin, Joan

    2015-01-01

    Task-Based Language Learning and Teaching has received sustained attention from teachers and researchers for over thirty years. It is a well-established pedagogy that includes the following characteristics: major focus on authentic and real-world tasks, choice of linguistic resources by learners, and a clearly defined non-linguistic outcome. This…

  17. Critical working tasks and determinants of exposure to bioaerosols and MVOC at composting facilities.

    PubMed

    Persoons, Renaud; Parat, Sylvie; Stoklov, Muriel; Perdrix, Alain; Maitre, Anne

    2010-09-01

    Airborne bioaerosols and Microbial Volatile Organic Compounds (MVOC) concentrations were simultaneously monitored at a composting facility and the main determinants of atmospheric concentrations were characterised, in order to help protect workers from potential adverse health effects. Microorganisms and MVOC were sampled during various process stages and working tasks, both on site at the two units (green waste and biowaste), and at the border of the composting facility. Ambient monitorings were performed at sampling points deemed representative of occupational exposures for critical working tasks, and additional individual samplings were done on workers for MVOC. A linear regression model was used to estimate the determinants explaining exposure variability to bioaerosols and volatile compounds. Bioaerosol concentrations ranging from 10(2) to 1.8x10(5)cfu/m(3) were observed, with peak exposures in the shredding and waste sieving phases. Shredder and siever adjustments, cleaning and maintenance of aeration systems/composting containers were associated with the highest bioaerosols ambient concentrations. MVOC concentration profiles were highly variable depending on the composting unit. Shredding/rotting phases were associated with the highest levels at respectively green waste/biowaste units. Terpenoids and alcohols were the most predominant compounds, and total MVOC levels reached up to 40mg/m(3). Individual and ambient MVOC concentrations did not show significant differences. "Season", "waste turning", "process stage" and "sampling location" were the main determinants of bioaerosols and MVOC concentrations variability. Moderate or no correlation was found between microorganisms and volatile organic compounds concentrations. The high bioaerosol and MVOC levels observed as well as the potential of additive irritative effects resulting from these exposures justify the wearing of personal protective equipments for the associated working tasks. On the other hand, low

  18. Applications of Task-Based Learning in TESOL

    ERIC Educational Resources Information Center

    Shehadeh, Ali, Ed.; Coombe, Christine, Ed.

    2010-01-01

    Why are many teachers around the world moving toward task-based learning (TBL)? This shift is based on the strong belief that TBL facilitates second language acquisition and makes second language learning and teaching more principled and effective. Based on insights gained from using tasks as research tools, this volume shows how teachers can use…

  19. Abuse pattern of gestational toluene exposure alters behavior in rats in a "waiting-for-reward" task.

    PubMed

    Bowen, Scott E; Hannigan, John H; Cooper, Patrick B

    2009-01-01

    Toluene abuse during pregnancy is a world-wide public health concern although the neurobehavioral teratogenic effects of toluene at the high concentrations and binge-like exposure patterns typical of abuse remain understudied. We assessed the effects of binge prenatal toluene exposure on behavior reflective of impulsivity in rat offspring using a "waiting-for-reward" operant task. Timed-pregnant Sprague-Dawley rats were exposed for 15 min, twice daily, from gestational day (GD) 8 through GD20 to either air, 8000 ppm, 12,000 ppm or 16,000 ppm toluene in a static exposure system. At postnatal day 60, male and female offspring were trained to stable lever pressing in a standard fixed-ratio 50 (FR50) paradigm. A wait requirement was then introduced such that after each FR completion, a "free" pellet was delivered at increasing time intervals (2 s, 4 s, 6 s, etc.) until the rat pressed another lever which reinstated the FR50 component ("FR Reset"). A pattern of increased FR Resets and fewer total pellets received overall and during the wait component is interpretable as "impulsivity." The "wait" component assessment was repeated after the rats had been injected with varying doses of amphetamine. Consistent with our hypotheses, repeated binge prenatal toluene exposure appeared to increase impulsivity based upon decreases in the total number of free pellets received and mean waiting time. However, a toluene dose-dependent decrease in the number of FR Resets and in response rates under all conditions indicated there was a general impairment in performance in rats exposed prenatally to higher doses of toluene. Also, prenatal exposure to 12,000 ppm and 16,000 ppm toluene resulted in a hyposensitivity to the stimulatory effects of the amphetamine challenge in male rats. For female rats, amphetamine further interfered with performance on the task. These results suggest that acute binge prenatal toluene exposure alters performance in this task but the results are not consistent

  20. Variability in mechanical exposure within and between individuals performing a highly constrained industrial work task.

    PubMed

    Mathiassen, Svend Erik; Möller, Therése; Forsman, Mikael

    2003-06-20

    Data on exposure variability is an important remedy for designing and interpreting studies of occupational ergonomics. The present study aimed at retrieving the within- and between-subjects variance of several mechanical exposure parameters in a repeated, short-cycle task. Seven experienced operators repeatedly secured joints using two types of hand-held nutrunners. The joints were placed in three different locations on a rack, simulating automotive assembly. Bilateral muscle activity from the upper trapezius and the lower arm extensors, as well as head and upper arm inclination was continuously monitored. Exposure levels and their variance components were assessed in several data subsets using ANOVA. The results were interpreted in terms of statistical precision and power, and discussed as markers of important ergonomic qualities. A substantial exposure variability was found within and between subjects in all joint locations and for both tools. For mixed work across tools and locations, the necessary number of subjects to arrive at a group mean exposure with 95% confidence limits corresponding to +/- 10% of the mean ranged between 8 and 158, with posture recordings tending to require smaller populations than muscle activity recordings. Within-subject variance increased 2- to 37-fold, depending on exposure parameter, when work was 'enlarged' from securings with a specified location and tool to a mix of all locations and tools. Systematic differences between subjects in variability and responsiveness to 'work enlargement' indicated individualized motor control strategies. The results illustrate the importance of exposure variability data to the design of proper measurement strategies. They also suggest that the sizes of exposure variability per se can be interpreted as operational indices of what is thought to be important ergonomic risk indicators, such as the 'sameness' of repeated operations and the allowance for flexible working techniques.

  1. Ordering design tasks based on coupling strengths

    NASA Technical Reports Server (NTRS)

    Rogers, James L., Jr.; Bloebaum, Christina L.

    1994-01-01

    The design process associated with large engineering systems requires an initial decomposition of the complex system into modules of design tasks which are coupled through the transference of output data. In analyzing or optimizing such a coupled system, it is essential to be able to determine which interactions figure prominently enough to significantly affect the accuracy of the system solution. Many decomposition approaches assume the capability is available to determine what design tasks and interactions exist and what order of execution will be imposed during the analysis process. Unfortunately, this is often a complex problem and beyond the capabilities of a human design manager. A new feature for DeMAID (Design Manager's Aid for Intelligent Decomposition) will allow the design manager to use coupling strength information to find a proper sequence for ordering the design tasks. In addition, these coupling strengths aid in deciding if certain tasks or couplings could be removed (or temporarily suspended) from consideration to achieve computational savings without a significant loss of system accuracy. New rules are presented and two small test cases are used to show the effects of using coupling strengths in this manner.

  2. Ordering Design Tasks Based on Coupling Strengths

    NASA Technical Reports Server (NTRS)

    Rogers, J. L.; Bloebaum, C. L.

    1994-01-01

    The design process associated with large engineering systems requires an initial decomposition of the complex system into modules of design tasks which are coupled through the transference of output data. In analyzing or optimizing such a coupled system, it is essential to be able to determine which interactions figure prominently enough to significantly affect the accuracy of the system solution. Many decomposition approaches assume the capability is available to determine what design tasks and interactions exist and what order of execution will be imposed during the analysis process. Unfortunately, this is often a complex problem and beyond the capabilities of a human design manager. A new feature for DeMAID (Design Manager's Aid for Intelligent Decomposition) will allow the design manager to use coupling strength information to find a proper sequence for ordering the design tasks. In addition, these coupling strengths aid in deciding if certain tasks or couplings could be removed (or temporarily suspended) from consideration to achieve computational savings without a significant loss of system accuracy. New rules are presented and two small test cases are used to show the effects of using coupling strengths in this manner.

  3. Exploring the effects of seated whole body vibration exposure on repetitive asymmetric lifting tasks.

    PubMed

    Mehta, Jay P; Lavender, Steven A; Jagacinski, Richard J; Sommerich, Carolyn M

    2015-01-01

    This study investigated changes in the physiological and behavioral responses to repetitive asymmetric lifting activity after exposure to whole body vibrations. Seventeen healthy volunteers repeatedly lifted a box (15% of lifter's capacity) positioned in front of them at ankle level to a location on their left side at waist level at the rate of 10 lifts/min for a period of 60 minutes. Prior to lifting, participants were seated on a vibrating platform for 60 minutes; in one of the two sessions the platform did not vibrate. Overall, the physiological responses assessed using near-infrared spectroscopy signals for the erector spinae muscles decreased significantly over time during the seating and the lifting tasks (p < 0.001). During repetitive asymmetric lifting, behavioral changes included increases in peak forward bending motion, twisting movement, and three-dimensional movement velocities of the spine. The lateral bending movement of the spine and the duration of each lift decreased significantly over the 60 minutes of repetitive lifting. With exposure to whole body vibration, participants twisted farther (p = 0.046) and twisted faster (p = 0.025). These behavioral changes would suggest an increase in back injury risk when repetitive lifting tasks are preceded by whole body vibration exposure.

  4. Task-Based Variability in Children's Singing Accuracy

    ERIC Educational Resources Information Center

    Nichols, Bryan E.

    2013-01-01

    The purpose of this study was to explore task-based variability in children's singing accuracy performance. The research questions were: Does children's singing accuracy vary based on the nature of the singing assessment employed? Is there a hierarchy of difficulty and discrimination ability among singing assessment tasks? What is the…

  5. An Agent-Based Cockpit Task Management System

    NASA Technical Reports Server (NTRS)

    Funk, Ken

    1997-01-01

    An agent-based program to facilitate Cockpit Task Management (CTM) in commercial transport aircraft is developed and evaluated. The agent-based program called the AgendaManager (AMgr) is described and evaluated in a part-task simulator study using airline pilots.

  6. The ability of non-computer tasks to increase biomechanical exposure variability in computer-intensive office work.

    PubMed

    Barbieri, Dechristian França; Srinivasan, Divya; Mathiassen, Svend Erik; Nogueira, Helen Cristina; Oliveira, Ana Beatriz

    2015-01-01

    Postures and muscle activity in the upper body were recorded from 50 academics office workers during 2 hours of normal work, categorised by observation into computer work (CW) and three non-computer (NC) tasks (NC seated work, NC standing/walking work and breaks). NC tasks differed significantly in exposures from CW, with standing/walking NC tasks representing the largest contrasts for most of the exposure variables. For the majority of workers, exposure variability was larger in their present job than in CW alone, as measured by the job variance ratio (JVR), i.e. the ratio between min-min variabilities in the job and in CW. Calculations of JVRs for simulated jobs containing different proportions of CW showed that variability could, indeed, be increased by redistributing available tasks, but that substantial increases could only be achieved by introducing more vigorous tasks in the job, in casu illustrated by cleaning.

  7. Pesticide exposure and sprayer's task goals: comparison between vineyards and greenhouses.

    PubMed

    Lambert, Mandy; Richardson, James; Grimbuhler, Sonia

    2012-01-01

    Plant protection products are used in agriculture to improve yields, but this use can cause contamination of the environment and is also likely to have adverse short and long term effects on agricultural workers. The field study took place in greenhouses and vineyards where operators are involved in high levels of pesticide spraying. The objective of this intervention was to identify factors explaining the influence of task factors on the exposure of greenhouse growers and vineyard workers. Thirteen operators were selected for detailed observations during one session of spraying. Video recordings provide counts of physical contacts between the operator and all the surrounding surfaces during the spraying operation. Both in vineyards and in greenhouses, physical and temporal constraints are the predominant factors in establishing a specific spraying procedure. Every action taken by the operator is a result of a compromise between safety, task performance and quality.

  8. Examination of computer task exposures in radiologists: a work systems approach.

    PubMed

    Robertson, Michelle M; Boiselle, Philip; Eisenberg, Ronald; Siegal, Dainel; Chang, Che-Hsu Joe; Dainoff, Marvin; Garabet, Angela; Garza, Jennifer Bruno; Dennerlein, Jack

    2012-01-01

    Radiologists are intensive computer users as they review and interpret radiological examinations using the Picture Archiving and Communication Systems (PACS). Since their computer tasks require the prolonged use of pointing devices, a high prevalence of Musculoskeletal Disorders (MSDs) is reported. The first phase of this study involved conducting a Cognitive Work Analysis in conjunction with a Participatory Ergonomics approach to perform a total work system analysis. We also conducted an ergonomic survey as well as collected computer use data, specifically for the mouse and keyboard. The goal of the study was to reduce the physical exposures for radiologists. This paper presents Phase I results describing the analyses and redesign process of the radiologists tasks, training design, computer use, and selected survey results.

  9. Enhancing speech learning by combining task practice with periods of stimulus exposure without practice.

    PubMed

    Wright, Beverly A; Baese-Berk, Melissa M; Marrone, Nicole; Bradlow, Ann R

    2015-08-01

    Language acquisition typically involves periods when the learner speaks and listens to the new language, and others when the learner is exposed to the language without consciously speaking or listening to it. Adaptation to variants of a native language occurs under similar conditions. Here, speech learning by adults was assessed following a training regimen that mimicked this common situation of language immersion without continuous active language processing. Experiment 1 focused on the acquisition of a novel phonetic category along the voice-onset-time continuum, while Experiment 2 focused on adaptation to foreign-accented speech. The critical training regimens of each experiment involved alternation between periods of practice with the task of phonetic classification (Experiment 1) or sentence recognition (Experiment 2) and periods of stimulus exposure without practice. These practice and exposure periods yielded little to no improvement separately, but alternation between them generated as much or more improvement as did practicing during every period. Practice appears to serve as a catalyst that enables stimulus exposures encountered both during and outside of the practice periods to contribute to quite distinct cases of speech learning. It follows that practice-plus-exposure combinations may tap a general learning mechanism that facilitates language acquisition and speech processing.

  10. Enhancing speech learning by combining task practice with periods of stimulus exposure without practice

    PubMed Central

    Wright, Beverly A.; Baese-Berk, Melissa M.; Marrone, Nicole; Bradlow, Ann R.

    2015-01-01

    Language acquisition typically involves periods when the learner speaks and listens to the new language, and others when the learner is exposed to the language without consciously speaking or listening to it. Adaptation to variants of a native language occurs under similar conditions. Here, speech learning by adults was assessed following a training regimen that mimicked this common situation of language immersion without continuous active language processing. Experiment 1 focused on the acquisition of a novel phonetic category along the voice-onset-time continuum, while Experiment 2 focused on adaptation to foreign-accented speech. The critical training regimens of each experiment involved alternation between periods of practice with the task of phonetic classification (Experiment 1) or sentence recognition (Experiment 2) and periods of stimulus exposure without practice. These practice and exposure periods yielded little to no improvement separately, but alternation between them generated as much or more improvement as did practicing during every period. Practice appears to serve as a catalyst that enables stimulus exposures encountered both during and outside of the practice periods to contribute to quite distinct cases of speech learning. It follows that practice-plus-exposure combinations may tap a general learning mechanism that facilitates language acquisition and speech processing. PMID:26328708

  11. Instruction-based task-rule congruency effects.

    PubMed

    Liefooghe, Baptist; Wenke, Dorit; De Houwer, Jan

    2012-09-01

    In the present study, we investigated the functional characteristics of task sets that were never applied before and were formed only on the basis of instructions. We tested if such task sets could elicit a task-rule congruency effect, which implies the automatic activation of responses in the context of another task. To this end, a novel procedure was developed that revealed instruction-based task-rule congruency effects in 2 experiments. Although the effect seems quite general (Experiment 1), it still necessitates the formation of a task set, as it cannot be induced by the mere maintenance of instructions in declarative working memory (Experiment 2). We conclude that a task set representing only key features of an upcoming task can be formed on the basis of instructions alone to such a degree that it can automatically trigger a response tendency in another task. Implications of our results for the impact of instructions on performance in general and for the occurrence of task-rule congruency effects in particular are discussed.

  12. Maintenance Task Data Base for Buildings: Plumbing Systems.

    DTIC Science & Technology

    1991-05-01

    COVERED May 199: Final 4. TITLE AND SUBTITLE 5 . FUNDING NUMBERS Maintenance Task Data for Buildings: Plumbing Systems RDTE dated 1980 6. AUTHOR(S) REIMB...Director. 2 CONTENTS Page SF298 1 FOREWORD 2 INTRODUCTION 5 ...................................................... Background Research Performed and Reports...Tables 4 DATA BASE APPLICATION EXAMPLES ................................... 15 5 PROCEDURES FOR DEVELOPING TASKS ................................. 16

  13. The Video-Based Short Comment Writing Task

    ERIC Educational Resources Information Center

    Pino-Silva, Juan

    2007-01-01

    Composing from sources may no longer be the exclusive domain of reading-to-write activities. The ever-increasing presence of video technology and broadcasting in academic settings could place listening-to-write tasks on a similar footing. This article describes a listening-to-write task, the video-based short comment, which (1) uses video as…

  14. Designing Digital Problem Based Learning Tasks that Motivate Students

    ERIC Educational Resources Information Center

    van Loon, Anne-Marieke; Ros, Anje; Martens, Rob

    2013-01-01

    This study examines whether teachers are able to apply the principles of autonomy support and structure support in designing digital problem based learning (PBL) tasks. We examine whether these tasks are more autonomy- and structure-supportive and whether primary and secondary school students experience greater autonomy, competence, and motivation…

  15. A Guide to Task Analysis for Competency Based Education. Health Occupations. Task Linkage Project Publication No. 4.

    ERIC Educational Resources Information Center

    Georgia State Univ., Atlanta. School of Education.

    Developed through synthesis and review of existing task analysis literature, this guide lists tasks expected to be performed by workers in ten health occupations and presents information for incorporating these tasks into articulated secondary and postsecondary competency based educational programs. Task listings are presented for the following…

  16. Instruction-based response activation depends on task preparation.

    PubMed

    Liefooghe, Baptist; De Houwer, Jan; Wenke, Dorit

    2013-06-01

    An increasing number of studies have demonstrated that a response in one task can be activated automatically on the basis merely of instructed stimulus-response (S-R) mappings belonging to another task. Such instruction-based response activations are considered to be evidence for the formation of S-R associations on the basis of the S-R mappings for an upcoming, but not yet executed, task. A crucial but somewhat neglected assumption is that instructed S-R associations are formed only under conditions that impose a sufficient degree of task preparation. Accordingly, in the present study we investigated the relation between task preparation and the instruction-based task-rule congruency effect, which is an index of response activation on the basis of instructions. The results from two experiments demonstrated that merely instructed S-R mappings of a particular task only elicit instruction-based response activations when that task is prepared for to a sufficient degree. Implications are discussed for the representation of instructed S-R mappings in working memory.

  17. Task-Based Language Teaching: An Empirical Study of Task Transfer

    ERIC Educational Resources Information Center

    Benson, Susan D.

    2016-01-01

    Since the 1980s, task-based language teaching (TBLT) has enjoyed considerable interest from researchers of second language acquisition (SLA), resulting in a growing body of empirical evidence to support how and to what extent this approach can promote language learning. Although transferability and generalizability are critical assumptions for…

  18. Tinkering with Tasks Knows No Bounds: ESL Teachers' Adaptations of Task-Based Language-Teaching

    ERIC Educational Resources Information Center

    Plews, John L.; Zhao, Kangxian

    2010-01-01

    Research on implementing task-based language-teaching (TBLT) shows that adapting TBLT in ways that are inconsistent with its principles is common among nonnative-speaker English-as-a-foreign-language teachers. Our study of Canadian native-speaker English-as-a-second language teachers reveals how they also adapt TBLT in ways that are incongruent…

  19. Microevaluating Learners' Task-Specific Motivation in a Task-Based Business Spanish Course

    ERIC Educational Resources Information Center

    Torres, Julio; Serafini, Ellen J.

    2016-01-01

    Scholars of task-based language teaching (TBLT) advocate for the identification of learners' communicative needs to inform syllabus design, particularly in language for specific purposes contexts (e.g., Long 2015). However, little research has applied TBLT principles in designing Spanish for specific purposes curricula. Moreover, despite the…

  20. Task-Based Flocking Algorithm for Mobile Robot Cooperation

    NASA Astrophysics Data System (ADS)

    He, Hongsheng; Ge, Shuzhi Sam; Tong, Guofeng

    In this paper, one task-based flocking algorithm that coordinates a swarm of robots is presented and evaluated based on the standard simulation platform. Task-based flocking algorithm(TFA) is an effective framework for mobile robots cooperation. Flocking behaviors are integrated into the cooperation of the multi-robot system to organize a robot team to achieve a common goal. The goal of the whole team is obtained through the collaboration of the individual robot’s task. The flocking model is presented, and the flocking energy function is defined based on that model to analyze the stability of the flocking and the task switching criterion. The simulation study is conducted in a five-versus-five soccer game, where the each robot dynamically selects its task in accordance with status and the whole robot team behaves as a flocking. Through simulation results and experiments, it is proved that the task-based flocking algorithm can effectively coordinate and control the robot flock to achieve the goal.

  1. Exposure to Blue Light Increases Subsequent Functional Activation of the Prefrontal Cortex During Performance of a Working Memory Task

    PubMed Central

    Alkozei, Anna; Smith, Ryan; Pisner, Derek A.; Vanuk, John R.; Berryhill, Sarah M.; Fridman, Andrew; Shane, Bradley R.; Knight, Sara A.; Killgore, William D.S.

    2016-01-01

    Study Objectives: Prolonged exposure to blue wavelength light has been shown to have an alerting effect, and enhances performance on cognitive tasks. A small number of studies have also shown that relatively short exposure to blue light leads to changes in functional brain responses during the period of exposure. The extent to which blue light continues to affect brain functioning during a cognitively challenging task after cessation of longer periods of exposure (i.e., roughly 30 minutes or longer), however, has not been fully investigated. Methods: A total of 35 healthy participants (18 female) were exposed to either blue (469 nm) (n = 17) or amber (578 nm) (n = 18) wavelength light for 30 minutes in a darkened room, followed immediately by functional magnetic resonance imaging (fMRI) while undergoing a working memory task (N-back task). Results: Participants in the blue light condition were faster in their responses on the N-back task and showed increased activation in the dorsolateral (DLPFC) and ventrolateral (VLPFC) prefrontal cortex compared to those in the amber control light condition. Furthermore, greater activation within the VLPFC was correlated with faster N-back response times. Conclusions: This is the first study to suggest that a relatively brief, single exposure to blue light has a subsequent beneficial effect on working memory performance, even after cessation of exposure, and leads to temporarily persisting functional brain changes within prefrontal brain regions associated with executive functions. These findings may have broader implication for using blue-enriched light in a variety of work settings where alertness and quick decision-making are important. Citation: Alkozei A, Smith R, Pisner DA, Vanuk JR, Berryhill SM, Fridman A, Shane BR, Knight SA, Killgore WD. Exposure to blue light increases subsequent functional activation of the prefrontal cortex during performance of a working memory task. SLEEP 2016;39(9):1671–1680. PMID:27253770

  2. An exposure indicator for digital radiography: AAPM Task Group 116 (Executive Summary)

    SciTech Connect

    Shepard, S. Jeff; Wang Jihong; Flynn, Michael; and others

    2009-07-15

    Digital radiographic imaging systems, such as those using photostimulable storage phosphor, amorphous selenium, amorphous silicon, CCD, and MOSFET technology, can produce adequate image quality over a much broader range of exposure levels than that of screen/film imaging systems. In screen/film imaging, the final image brightness and contrast are indicative of over- and underexposure. In digital imaging, brightness and contrast are often determined entirely by digital postprocessing of the acquired image data. Overexposure and underexposures are not readily recognizable. As a result, patient dose has a tendency to gradually increase over time after a department converts from screen/film-based imaging to digital radiographic imaging. The purpose of this report is to recommend a standard indicator which reflects the radiation exposure that is incident on a detector after every exposure event and that reflects the noise levels present in the image data. The intent is to facilitate the production of consistent, high quality digital radiographic images at acceptable patient doses. This should be based not on image optical density or brightness but on feedback regarding the detector exposure provided and actively monitored by the imaging system. A standard beam calibration condition is recommended that is based on RQA5 but uses filtration materials that are commonly available and simple to use. Recommendations on clinical implementation of the indices to control image quality and patient dose are derived from historical tolerance limits and presented as guidelines.

  3. Early Childhood Household Smoke Exposure Predicts Less Task-Oriented Classroom Behavior at Age 10.

    PubMed

    Pagani, Linda S; Fitzpatrick, Caroline

    2016-10-01

    Secondhand tobacco smoke is considered a developmental neurotoxicant especially given underdeveloped vital systems in young children. An ecological test of its negative influence on brain development can be made by examining the prospective association between early childhood household smoke exposure and later classroom behavior. Using a longitudinal birth cohort, we examined the unique contribution of household tobacco smoke exposure to children's subsequent classroom engagement at age 10. From child ages 1.5 to 7 years, parents of 2,055 participants from the Quebec Longitudinal Study of Child Development reported on household smoking by themselves and other home occupants. At age 10, fourth-grade teachers reported on the child's classroom engagement. In terms of prevalence, 58% of parents reported that their children were never exposed to smoke in the home, while 34% and 8% of children were exposed to transient and continuous household smoke, respectively. Compared with never exposed children, those who were exposed to transient and continuous household smoke scored 13% and 9% of a standard deviation lower on classroom engagement in fourth grade, standardized B = -.128 (95% confidence interval = -.186, -.069) and standardized B = -.093 (95% confidence interval = -.144, -.043), respectively. Compared with their never exposed peers, children exposed to transient and continuous early childhood household smoke showed proportionately less classroom engagement, which reflects task-orientation, following directions, and working well autonomously and with others. This predisposition poses risks for high school dropout, which from a population health perspective is closely linked with at-risk lifestyle habits and unhealthy outcomes.

  4. The nature of impulsivity: visual exposure to natural environments decreases impulsive decision-making in a delay discounting task.

    PubMed

    Berry, Meredith S; Sweeney, Mary M; Morath, Justice; Odum, Amy L; Jordan, Kerry E

    2014-01-01

    The benefits of visual exposure to natural environments for human well-being in areas of stress reduction, mood improvement, and attention restoration are well documented, but the effects of natural environments on impulsive decision-making remain unknown. Impulsive decision-making in delay discounting offers generality, predictive validity, and insight into decision-making related to unhealthy behaviors. The present experiment evaluated differences in such decision-making in humans experiencing visual exposure to one of the following conditions: natural (e.g., mountains), built (e.g., buildings), or control (e.g., triangles) using a delay discounting task that required participants to choose between immediate and delayed hypothetical monetary outcomes. Participants viewed the images before and during the delay discounting task. Participants were less impulsive in the condition providing visual exposure to natural scenes compared to built and geometric scenes. Results suggest that exposure to natural environments results in decreased impulsive decision-making relative to built environments.

  5. EFL Reading Instruction: Communicative Task-Based Approach

    ERIC Educational Resources Information Center

    Sidek, Harison Mohd

    2012-01-01

    The purpose of this study was to examine the overarching framework of EFL (English as a Foreign Language) reading instructional approach reflected in an EFL secondary school curriculum in Malaysia. Based on such analysis, a comparison was made if Communicative Task-Based Language is the overarching instructional approach for the Malaysian EFL…

  6. Reward-based learning of a redundant task.

    PubMed

    Tamagnone, Irene; Casadio, Maura; Sanguineti, Vittorio

    2013-06-01

    Motor skill learning has different components. When we acquire a new motor skill we have both to learn a reliable action-value map to select a highly rewarded action (task model) and to develop an internal representation of the novel dynamics of the task environment, in order to execute properly the action previously selected (internal model). Here we focus on a 'pure' motor skill learning task, in which adaptation to a novel dynamical environment is negligible and the problem is reduced to the acquisition of an action-value map, only based on knowledge of results. Subjects performed point-to-point movement, in which start and target positions were fixed and visible, but the score provided at the end of the movement depended on the distance of the trajectory from a hidden viapoint. Subjects did not have clues on the correct movement other than the score value. The task is highly redundant, as infinite trajectories are compatible with the maximum score. Our aim was to capture the strategies subjects use in the exploration of the task space and in the exploitation of the task redundancy during learning. The main findings were that (i) subjects did not converge to a unique solution; rather, their final trajectories are determined by subject-specific history of exploration. (ii) with learning, subjects reduced the trajectory's overall variability, but the point of minimum variability gradually shifted toward the portion of the trajectory closer to the hidden via-point.

  7. Performance on a strategy set shifting task in rats following adult or adolescent cocaine exposure

    PubMed Central

    Kantak, Kathleen M.; Barlow, Nicole; Tassin, David H.; Brisotti, Madeline F.; Jordan, Chloe J

    2014-01-01

    Rationale Neuropsychological testing is widespread in adult cocaine abusers, but lacking in teens. Animal models may provide insight into age-related neuropsychological consequences of cocaine exposure. Objectives Determine whether developmental plasticity protects or hinders behavioral flexibility after cocaine exposure in adolescent vs. adult rats. Methods Using a yoked-triad design, one rat controlled cocaine delivery and the other two passively received cocaine or saline. Rats controlling cocaine delivery (1.0 mg/kg) self-administered for 18 sessions (starting P37 or P77), followed by 18 drug-free days. Rats next were tested in a strategy set shifting task, lasting 11–13 sessions. Results Cocaine self-administration did not differ between age groups. During initial set formation, adolescent-onset groups required more trials to reach criterion and made more errors than adult-onset groups. During the set shift phase, rats with adult-onset cocaine self-administration experience had higher proportions of correct trials and fewer perseverative + regressive errors than age-matched yoked-controls or rats with adolescent-onset cocaine self-administration experience. During reversal learning, rats with adult-onset cocaine experience (self-administered or passive) required fewer trials to reach criterion and the self-administering rats made fewer perseverative + regressive errors than yoked-saline rats. Rats receiving adolescent-onset yoked-cocaine had more trial omissions and longer lever press reaction times than age-matched rats self-administering cocaine or receiving yoked-saline. Conclusions Prior cocaine self-administration may impair memory to reduce proactive interference during set shifting and reversal learning in adult-onset but not adolescent-onset rats (developmental plasticity protective). Passive cocaine may disrupt aspects of executive function in adolescent-onset but not adult-onset rats (developmental plasticity hinders). PMID:24800898

  8. Task-Based Language Teaching and Expansive Learning Theory

    ERIC Educational Resources Information Center

    Robertson, Margaret

    2014-01-01

    Task-Based Language Teaching (TBLT) has become increasingly recognized as an effective pedagogy, but its location in generalized sociocultural theories of learning has led to misunderstandings and criticism. The purpose of this article is to explain the congruence between TBLT and Expansive Learning Theory and the benefits of doing so. The merit…

  9. Technology and Task-Based Language Teaching: A Critical Review

    ERIC Educational Resources Information Center

    Lai, Chun; Li, Guofang

    2011-01-01

    Task-based language teaching (TBLT) has been drawing researchers' and practitioners' attention since its onset in the 1980s. The rich and still expanding literature on TBLT is helping to mature both its theoretical conceptualization and practical implementation in foreign and second language education. Technology has played and will continue to…

  10. "New Tricks": Teachers Talk about Task-Based Language Teaching

    ERIC Educational Resources Information Center

    Erlam, Rosemary

    2014-01-01

    Over the past 20 years task-based language teaching (TBLT) has become a dominant approach to teaching in many contexts, including schools in New Zealand and the Flemish speaking region of Belgium (East, 2012; Van den Branden, 2006), but there are challenges for teachers in adapting their teaching to this approach. This paper reports on a study…

  11. Mother Tongue Use in Task-Based Language Teaching Model

    ERIC Educational Resources Information Center

    Hung, Nguyen Viet

    2012-01-01

    Researches of English language teaching (ELT) have focused on using mother tongue (L1) for years. The proliferation of task-based language teaching (TBLT) has been also occurred. Considerable findings have been made in the existing literature of the two fields; however, no mentions have been made in the combination of these two ELT aspects, i.e.,…

  12. Partners in Learning: A Task-based Advanced Speaking Course.

    ERIC Educational Resources Information Center

    O'Brien, Maureen

    This report describes a semester of teaching a group of non-native English-speaking students, aged 17 to 40 years and how the instructor identified three elements that appeared to be necessary for a task-based, advanced English speaking class. The three elements were: (1) ongoing needs assessment; (2) collaboration between instructor and students…

  13. Web-Based Elicitation Tasks in SLA Research.

    ERIC Educational Resources Information Center

    Ayoun, Dalila

    2000-01-01

    Studied second language acquisition (SLA) designed with Web-based elicitation tasks to obtain greater internal and external validity. Tested the acquisition of the properties subsumed under the verb movement parameter and the null subject parameter by English native speakers enrolled in college French. (Author/VWL)

  14. Task-based Learning (TBL) in Undergraduate Medical Education.

    ERIC Educational Resources Information Center

    Virjo, Irma; Holmberg-Marttila, Doris; Mattila, Kari

    2001-01-01

    Describes task-based learning (TBL), a study module for fourth-year medical students (n=85), and experiences with implementing it at the University of Tampere in Finland. Indicates that this method works and that it leads to learning. Students evaluate their skills connected with a general practitioner's work in health center hospitals as better…

  15. Positive versus Negative Communication Strategies in Task-Based Learning

    ERIC Educational Resources Information Center

    Rohani, Siti

    2013-01-01

    This study aimed at describing how the implementation of Task-Based Learning (TBL) would shape or change students' use of oral communication strategies. Students' problems and strategies to solve the problems during the implementation of TBL were also explored. The study was a mixed method, employing both quantitative and qualitative analysis…

  16. The Campus-Based Formula. NASFAA Task Force Report

    ERIC Educational Resources Information Center

    National Association of Student Financial Aid Administrators, 2014

    2014-01-01

    The primary purpose of the National Association of Student Financial Aid Administrators (NASFAA) Campus-Based Aid Allocation Task Force was to examine the formula by which congressional appropriations for the Federal Supplemental Educational Opportunity Grant (FSEOG), Federal Work-Study (FWS), and Perkins Loan programs are distributed to schools,…

  17. Collaborative Tasks in Wiki-Based Environment in EFL Learning

    ERIC Educational Resources Information Center

    Zou, Bin; Wang, Dongshuo; Xing, Minjie

    2016-01-01

    Wikis provide users with opportunities to post and edit messages to collaborate in the language learning process. Many studies have offered findings to show positive impact of Wiki-based language learning for learners. This paper explores the effect of collaborative task in error correction for English as a Foreign Language learning in an online…

  18. Strategy Training in a Task-Based Language Classroom

    ERIC Educational Resources Information Center

    Lai, Chun; Lin, Xiaolin

    2015-01-01

    Recent literature that examines the implementation of task-based language teaching (TBLT) in classroom settings has reported various challenges related to educational cultures, classroom management, teacher cognition and learner perceptions. To facilitate the smooth transition of TBLT from laboratory settings to classroom contexts, measures need…

  19. Effect of continuous gamma-ray exposure on performance of learned tasks and effect of subsequent fractionated exposures on blood-forming tissue

    NASA Technical Reports Server (NTRS)

    Spalding, J. F.; Holland, L. M.; Prine, J. R.; Farrer, D. N.; Braun, R. G.

    1972-01-01

    Sixteen monkeys trained to perform continuous and discrete-avoidance and fixed-ratio tasks with visual and auditory cues were performance-tested before, during, and after 10-day gamma-ray exposures totaling 0, 500, 750, and 1000 rads. Approximately 14 months after the performance-test exposures, surviving animals were exposed to 100-rad gamma-ray fractions at 56-day intervals to observe injury and recovery patterns of blood-forming tissues. The fixed-ratio, food-reward task performance showed a transient decline in all dose groups within 24 hours of the start of gamma-ray exposure, followed by recovery to normal food-consumption levels within 48 to 72 hours. Avoidance tasks were performed successfully by all groups during the 10-day exposure, but reaction times of the two higher dose-rate groups in which animals received 3 and 4 rads per hour or total doses of 750 and 1000 rads, respectively, were somewhat slower.

  20. EEG based topography analysis in string recognition task

    NASA Astrophysics Data System (ADS)

    Ma, Xiaofei; Huang, Xiaolin; Shen, Yuxiaotong; Qin, Zike; Ge, Yun; Chen, Ying; Ning, Xinbao

    2017-03-01

    Vision perception and recognition is a complex process, during which different parts of brain are involved depending on the specific modality of the vision target, e.g. face, character, or word. In this study, brain activities in string recognition task compared with idle control state are analyzed through topographies based on multiple measurements, i.e. sample entropy, symbolic sample entropy and normalized rhythm power, extracted from simultaneously collected scalp EEG. Our analyses show that, for most subjects, both symbolic sample entropy and normalized gamma power in string recognition task are significantly higher than those in idle state, especially at locations of P4, O2, T6 and C4. It implies that these regions are highly involved in string recognition task. Since symbolic sample entropy measures complexity, from the perspective of new information generation, and normalized rhythm power reveals the power distributions in frequency domain, complementary information about the underlying dynamics can be provided through the two types of indices.

  1. Worker lead exposures during renovation of homes with lead-based paint

    SciTech Connect

    Sussell, A.; Gittleman, J.; Singal, M.

    1998-11-01

    The authors evaluated lead exposures among full-time home renovators and part-time volunteers working primarily in pre-1960 homes with lead-based paint. Potentially hazardous lead exposures were measured during two tasks: exterior dry scraping and wet scraping. Maximum exposures were 120 and 63 {micro}g/m{sup 3}, respectively. Exposures during other tasks, including general repair, weatherization, exterior scraping/painting, window replacement, demolition, and plumbing, were low, as were all 13 full-shift personal exposures. Blood lead levels for full-time workers ranged up to 17.5 {micro}g/dl, with a GM of 5.2 {micro}g/dl; the GM for volunteers was 3.2 {micro}g/dl. All of the paint samples collected from work surfaces had detectable amounts of lead, with 65% of the work surfaces tested having an average lead concentration of >0.5%.

  2. Task-based optimization of image reconstruction in breast CT

    NASA Astrophysics Data System (ADS)

    Sanchez, Adrian A.; Sidky, Emil Y.; Pan, Xiaochuan

    2014-03-01

    We demonstrate a task-based assessment of image quality in dedicated breast CT in order to optimize the number of projection views acquired. The methodology we employ is based on the Hotelling Observer (HO) and its associated metrics. We consider two tasks: the Rayleigh task of discerning between two resolvable objects and a single larger object, and the signal detection task of classifying an image as belonging to either a signalpresent or signal-absent hypothesis. HO SNR values are computed for 50, 100, 200, 500, and 1000 projection view images, with the total imaging radiation dose held constant. We use the conventional fan-beam FBP algorithm and investigate the effect of varying the width of a Hanning window used in the reconstruction, since this affects both the noise properties of the image and the under-sampling artifacts which can arise in the case of sparse-view acquisitions. Our results demonstrate that fewer projection views should be used in order to increase HO performance, which in this case constitutes an upper-bound on human observer performance. However, the impact on HO SNR of using fewer projection views, each with a higher dose, is not as significant as the impact of employing regularization in the FBP reconstruction through a Hanning filter.

  3. The Task Is Not Enough: Processing Approaches to Task-Based Performance

    ERIC Educational Resources Information Center

    Skehan, Peter; Xiaoyue, Bei; Qian, Li; Wang, Zhan

    2012-01-01

    This article reports on three research studies, all of which concern second language task performance. The first focuses on planning, and compares on-line and strategic planning as well as task repetition. The second study examines the role of familiarity on task performance, and compares this with conventional strategic planning. The third study…

  4. Promoting Task-Based Pragmatics Instruction in EFL Classroom Contexts: The Role of Task Complexity

    ERIC Educational Resources Information Center

    Kim, Youjin; Taguchi, Naoko

    2015-01-01

    Robinson's (2001) Cognition Hypothesis claims that more complex tasks promote interaction and language development. This study examined the effect of task complexity in the learning of request-making expressions. Task complexity was operationalized as [+/- reasoning] following Robinson's framework. The study employed a pretest-posttest research…

  5. Prototype Videodisk-Based Part-Task Thermal Imaging Trainer

    NASA Technical Reports Server (NTRS)

    Brickner, Michael S.; Foyle, David C.; Sridhar, Banavar (Technical Monitor)

    1995-01-01

    Thermal images, or infrared images, are representations of the world based on heat, instead of visible light. Research has shown that the resulting thermal image results in perceptual differences leading to difficulties in interpretation (e.g., the determination of slope angle, concavity/convexity), or increased identification latencies. A joint research project between the United States (NASA and U.S. Army) and Israel (Ministry of Defense and Israel Air Force) has resulted in the development of a prototype part-task trainer for the acquisition of perceptual skills associated with thermal imaging usage. This prototype system is videodisk-based under computer control, using recordings of thermal images. A lesson section introduces declarative knowledge, in which the basic physics and heuristics of thermal imagery are taught. An exercise section teaches procedural knowledge, with the user viewing dynamic, actual imagery, with an interactive detection/location determination task. The general philosophy and design of the trainer will be demonstrated.

  6. The Effects of Multimedia Task-Based Language Teaching on EFL Learners' Oral L2 Production

    ERIC Educational Resources Information Center

    BavaHarji, Madhubala; Gheitanchian, Mehrnaz; Letchumanan, Krishnaveni

    2014-01-01

    This study examined the effects of tasks, with varying levels of complexity, i.e. simple, + complex and ++ complex tasks on EFL learners' oral production in a multimedia task-based language teaching environment. 57 EFL adult learners carried out a total of 12 tasks, in sets of four tasks within three different themes and different levels of…

  7. Adolescent exposure to methylphenidate impairs serial pattern learning in the serial multiple choice (SMC) task in adult rats.

    PubMed

    Rowan, James D; McCarty, Madison K; Kundey, Shannon M A; Osburn, Crystal D; Renaud, Samantha M; Kelley, Brian M; Matoushek, Amanda Willey; Fountain, Stephen B

    2015-01-01

    The long-term effects of adolescent exposure to methylphenidate (MPD) on adult cognitive capacity are largely unknown. We utilized a serial multiple choice (SMC) task, which is a sequential learning paradigm for studying complex learning, to observe the effects of methylphenidate exposure during adolescence on later serial pattern acquisition during adulthood. Following 20.0mg/kg/day MPD or saline exposure for 5 days/week for 5 weeks during adolescence, male rats were trained to produce a highly structured serial response pattern in an octagonal operant chamber for water reinforcement as adults. During a transfer phase, a violation to the previously-learned pattern structure was introduced as the last element of the sequential pattern. Results indicated that while rats in both groups were able to learn the training and transfer patterns, adolescent exposure to MPD impaired learning for some aspects of pattern learning in the training phase which are learned using discrimination learning or serial position learning. In contrast adolescent exposure to MPD had no effect on other aspects of pattern learning which have been shown to tap into rule learning mechanisms. Additionally, adolescent MPD exposure impaired learning for the violation element in the transfer phase. This indicates a deficit in multi-item learning previously shown to be responsible for violation element learning. Thus, these results clearly show that adolescent MPD produced multiple cognitive impairments in male rats that persisted into adulthood long after MPD exposure ended.

  8. Teachers' Teaching Practices and Beliefs Regarding Context-Based Tasks and Their Relation with Students' Difficulties in Solving These Tasks

    ERIC Educational Resources Information Center

    Wijaya, Ariyadi; van den Heuvel-Panhuizen, Marja; Doorman, Michiel

    2015-01-01

    In this study, we investigated teachers' teaching practices and their underlying beliefs regarding context-based tasks to find a possible explanation for students' difficulties with these tasks. The research started by surveying 27 Junior High School teachers from seven schools in Indonesia through a written questionnaire. Then, to further examine…

  9. The Relationship between Amygdala Activation and Passive Exposure Time to an Aversive Cue during a Continuous Performance Task

    PubMed Central

    Strigo, Irina A.; Simmons, Alan N.; Matthews, Scott C.; Craig, Arthur D. (Bud)

    2010-01-01

    The allocation of attention modulates negative emotional processing in the amygdala. However, the role of passive exposure time to emotional signals in the modulation of amygdala activity during active task performance has not been examined. In two functional Magnetic Resonance Imaging (fMRI) experiments conducted in two different groups of healthy human subjects, we examined activation in the amygdala due to cued anticipation of painful stimuli while subjects performed a simple continuous performance task (CPT) with either a fixed or a parametrically varied trial duration. In the first experiment (N = 16), engagement in the CPT during a task with fixed trial duration produced the expected attenuation of amygdala activation, but close analysis suggested that the attenuation occurred during the period of active engagement in CPT, and that amygdala activity increased proportionately during the remainder of each trial, when subjects were passively exposed to the pain cue. In the second experiment (N = 12), the duration of each trial was parametrically varied, and we found that amygdala activation was linearly related to the time of passive exposure to the anticipatory cue. We suggest that amygdala activation during negative anticipatory processing depends directly on the passive exposure time to the negative cue. PMID:21124739

  10. A touchscreen based global motion perception task for mice.

    PubMed

    Stirman, Jeffrey N; Townsend, Leah B; Smith, Spencer L

    2016-10-01

    Global motion perception is a function of higher, or extrastriate, visual system circuitry. These circuits can be engaged in visually driven navigation, a behavior at which mice are adept. However, the properties of global motion perception in mice are unclear. Therefore, we developed a touchscreen-based, two-alternative forced choice (2AFC) task to explore global motion detection in mice using random dot kinematograms (RDK). Performance data was used to compute coherence thresholds for global motion perception. The touchscreen-based task allowed for parallel training and testing with multiple chambers and minimal experimenter intervention with mice performing hundreds of trials per session. Parameters of the random dot kinematograms, including dot size, lifetime, and speed, were tested. Mice learned to discriminate kinematograms whose median motion direction differed by 90 degrees in 7-24days after a 10-14day pre-training period. The average coherence threshold (measured at 70% correct) in mice for this task was 22±5%, with a dot diameter of 3.88mm and speed of 58.2mm/s. Our results confirm the ability of mice to perform global motion discriminations, and the touchscreen assay provides a flexible, automated, and relatively high throughput method with which to probe complex visual function in mice.

  11. The Nature of Impulsivity: Visual Exposure to Natural Environments Decreases Impulsive Decision-Making in a Delay Discounting Task

    PubMed Central

    Berry, Meredith S.; Sweeney, Mary M.; Morath, Justice; Odum, Amy L.; Jordan, Kerry E.

    2014-01-01

    The benefits of visual exposure to natural environments for human well-being in areas of stress reduction, mood improvement, and attention restoration are well documented, but the effects of natural environments on impulsive decision-making remain unknown. Impulsive decision-making in delay discounting offers generality, predictive validity, and insight into decision-making related to unhealthy behaviors. The present experiment evaluated differences in such decision-making in humans experiencing visual exposure to one of the following conditions: natural (e.g., mountains), built (e.g., buildings), or control (e.g., triangles) using a delay discounting task that required participants to choose between immediate and delayed hypothetical monetary outcomes. Participants viewed the images before and during the delay discounting task. Participants were less impulsive in the condition providing visual exposure to natural scenes compared to built and geometric scenes. Results suggest that exposure to natural environments results in decreased impulsive decision-making relative to built environments. PMID:24841421

  12. Effects of sitting and standing on upper extremity physical exposures in materials handling tasks.

    PubMed

    Cudlip, Alan C; Callaghan, Jack P; Dickerson, Clark R

    2015-01-01

    Sitting or standing work configurations modulate musculoskeletal risk. Most existing investigations of these configurations have either studied them separately or lacked focus on the upper extremity, particularly during manual materials handling (MMH) tasks. To address this gap, upper extremity loading in 20 male and 20 females were assessed in 4 MMH tasks in sitting and standing. Differences in electromyographic (EMG) activity, local joint moments and body discomfort between configurations were examined. Interactions between task and sit/stand configuration resulted in increases of up to 500% in joint moments, 94% in EMG activity and 880% in discomfort when tasks were completed while sitting (p < 0.01). Future MMH task designers should consider placing workers in standing postures when feasible to reduce upper extremity loading, but workers should not remain in either configuration for extended periods of time as the negative effects of both workspace geometries can instigate future musculoskeletal disorders. Practitioner Summary: Sitting and standing modify occupational musculoskeletal risk. We examined how performing identical tasks while sitting or standing altered upper extremity and low back loading. In general, sitting increased muscle activity and discomfort, while standing increased local joint moments. The benefits of standing outweighed those of sitting across the range of tasks.

  13. Task-based lens design with application to digital mammography.

    PubMed

    Chen, Liying; Barrett, Harrison H

    2005-01-01

    Recent advances in model observers that predict human perceptual performance now make it possible to optimize medical imaging systems for human task performance. We illustrate the procedure by considering the design of a lens for use in an optically coupled digital mammography system. The channelized Hotelling observer is used to model human performance, and the channels chosen are differences of Gaussians. The task performed by the model observer is detection of a lesion at a random but known location in a clustered lumpy background mimicking breast tissue. The entire system is simulated with a Monte Carlo application according to physics principles, and the main system component under study is the imaging lens that couples a fluorescent screen to a CCD detector. The signal-to-noise ratio (SNR) of the channelized Hotelling observer is used to quantify this detectability of the simulated lesion (signal) on the simulated mammographic background. Plots of channelized Hotelling SNR versus signal location for various lens apertures, various working distances, and various focusing places are presented. These plots thus illustrate the trade-off between coupling efficiency and blur in a task-based manner. In this way, the channelized Hotelling SNR is used as a merit function for lens design.

  14. Task-based lens design with application to digital mammography

    PubMed Central

    Chen, Liying; Barrett, Harrison H.

    2006-01-01

    Recent advances in model observers that predict human perceptual performance now make it possible to optimize medical imaging systems for human task performance. We illustrate the procedure by considering the design of a lens for use in an optically coupled digital mammography system. The channelized Hotelling observer is used to model human performance, and the channels chosen are differences of Gaussians. The task performed by the model observer is detection of a lesion at a random but known location in a clustered lumpy background mimicking breast tissue. The entire system is simulated with a Monte Carlo application according to physics principles, and the main system component under study is the imaging lens that couples a fluorescent screen to a CCD detector. The signal-to-noise ratio (SNR) of the channelized Hotelling observer is used to quantify this detectability of the simulated lesion (signal) on the simulated mammographic background. Plots of channelized Hotelling SNR versus signal location for various lens apertures, various working distances, and various focusing places are presented. These plots thus illustrate the trade-off between coupling efficiency and blur in a task-based manner. In this way, the channelized Hotelling SNR is used as a merit function for lens design. PMID:15669625

  15. Task-based lens design with application to digital mammography

    NASA Astrophysics Data System (ADS)

    Chen, Liying; Barrett, Harrison H.

    2005-01-01

    Recent advances in model observers that predict human perceptual performance now make it possible to optimize medical imaging systems for human task performance. We illustrate the procedure by considering the design of a lens for use in an optically coupled digital mammography system. The channelized Hotelling observer is used to model human performance, and the channels chosen are differences of Gaussians. The task performed by the model observer is detection of a lesion at a random but known location in a clustered lumpy background mimicking breast tissue. The entire system is simulated with a Monte Carlo application according to physics principles, and the main system component under study is the imaging lens that couples a fluorescent screen to a CCD detector. The signal-to-noise ratio (SNR) of the channelized Hotelling observer is used to quantify this detectability of the simulated lesion (signal) on the simulated mammographic background. Plots of channelized Hotelling SNR versus signal location for various lens apertures, various working distances, and various focusing places are presented. These plots thus illustrate the trade-off between coupling efficiency and blur in a task-based manner. In this way, the channelized Hotelling SNR is used as a merit function for lens design.

  16. Task Selection, Task Switching and Multitasking during Computer-Based Independent Study

    ERIC Educational Resources Information Center

    Judd, Terry

    2015-01-01

    Detailed logs of students' computer use, during independent study sessions, were captured in an open-access computer laboratory. Each log consisted of a chronological sequence of tasks representing either the application or the Internet domain displayed in the workstation's active window. Each task was classified using a three-tier schema…

  17. Paradoxical effects of injection stress and nicotine exposure experienced during adolescence on learning in a serial multiple choice (SMC) task in adult female rats.

    PubMed

    Renaud, Samantha M; Pickens, Laura R G; Fountain, Stephen B

    2015-01-01

    Nicotine exposure in adolescent rats has been shown to cause learning impairments that persist into adulthood long after nicotine exposure has ended. This study was designed to assess the extent to which the effects of adolescent nicotine exposure on learning in adulthood can be accounted for by adolescent injection stress experienced concurrently with adolescent nicotine exposure. Female rats received either 0.033 mg/h nicotine (expressed as the weight of the free base) or bacteriostatic water vehicle by osmotic pump infusion on postnatal days 25-53 (P25-53). Half of the nicotine-exposed rats and half of the vehicle rats also received twice-daily injection stress consisting of intraperitoneal saline injections on P26-53. Together these procedures produced 4 groups: No Nicotine/No Stress, Nicotine/No Stress, No Nicotine/Stress, and Nicotine/Stress. On P65-99, rats were trained to perform a structurally complex 24-element serial pattern of responses in the serial multiple choice (SMC) task. Four general results were obtained in the current study. First, learning for within-chunk elements was not affected by either adolescent nicotine exposure, consistent with past work (Pickens, Rowan, Bevins, and Fountain, 2013), or adolescent injection stress. Thus, there were no effects of adolescent nicotine exposure or injection stress on adult within-chunk learning typically attributed to rule learning in the SMC task. Second, adolescent injection stress alone (i.e., without concurrent nicotine exposure) caused transient but significant facilitation of adult learning restricted to a single element of the 24-element pattern, namely, the "violation element," that was the only element of the pattern that was inconsistent with pattern structure. Thus, adolescent injection stress alone facilitated violation element acquisition in adulthood. Third, also consistent with past work (Pickens et al., 2013), adolescent nicotine exposure, in this case both with and without adolescent

  18. The behavioral avoidance task using imaginal exposure (BATIE): a paper-and-pencil version of traditional in vivo behavioral avoidance tasks.

    PubMed

    Davis, Thompson E; Reuther, Erin T; May, Anna C; Rudy, Brittany M; Munson, Melissa S; Jenkins, Whitney S; Whiting, Sara E

    2013-12-01

    Behavioral avoidance tasks (BATs) have been used for decades in the assessment of specific phobias, but they also involve a number of prohibitive difficulties. This study investigated a new imaginal/self-report instrument, the Behavioral Avoidance Task Using Imaginal Exposure (BATIE), and evaluated whether it was an efficient paper-and-pencil alternative. Forty-nine adults diagnosed with specific phobias were matched to 49 participants without those particular phobias who served as control participants. The participants were 89.8% female and 79.6% Caucasian and had a mean age of 20.81 years (SD = 3.62). Diagnosis was determined using the Anxiety Disorders Interview Schedule (Brown, DiNardo, & Barlow, 1994). Participants completed a BAT following a BATIE. Results indicated BATIE ratings significantly correlated with BAT performance and ratings. Significant differences were also found between the phobic and control groups on all BATIE ratings (all differences indicated poorer performance or more fear in those with specific phobias). Also, the BATIE scores demonstrated good evidence of convergent and discriminant validity compared to other self-reports, significantly predicted BAT performance even when controlling for those measures of fear and anxiety, and significantly predicted diagnostic severity ratings. Overall, results indicated that the BATIE may be a reasonable alternative to in vivo BATs in certain situations (e.g., clinical practice, unavailability of BAT stimuli).

  19. The Task-Based Teaching of Writing to Big Classes in Chinese EFL Setting

    ERIC Educational Resources Information Center

    Hai-yan, Miao

    2014-01-01

    This paper explores how to teach English writing to big classes in China from the task-based perspective. Based on a comparison between the traditional 3Ps approach and the tasked-based approach, the paper proposes a practical linear procedure as to how to teach English writing in the task-based classroom to big classes. An empirical study is…

  20. Analysis of radiation exposure, Task Force RAZOR. Exercise Desert Rock VI, Operation Teapot. Technical report

    SciTech Connect

    Edwards, R.; Goetz, J.; Klemm, J.

    1983-07-15

    The radiation dose to Task Force RAZOR personnel participating in Shot Apple II of Operation Teapot, Exercise Desert Rock VI, is reconstructed. Task force personnel were exposed to initial radiation while in their vehicles or in trenches at the time of Apple II detonation. They were also exposed to residual radiation during their subsequent manuever and during an inspection of the equipment display area. The calculated total gamma doses to fully-participating Task Force RAZOR personnel range from about 0.8 rem to 1.8 rem. The highest dose was received by personnel of the armored infantry platoon on right flank nearest ground zero. Internal radiation dose commitments to maximally exposed personnel inside vehicles are estimated to be about 0.4 rem to the thyroid, 0.003 rem to the whole body, and 0.002 rem to the bone.

  1. The Time on Task Effect in Reading and Problem Solving Is Moderated by Task Difficulty and Skill: Insights from a Computer-Based Large-Scale Assessment

    ERIC Educational Resources Information Center

    Goldhammer, Frank; Naumann, Johannes; Stelter, Annette; Tóth, Krisztina; Rölke, Heiko; Klieme, Eckhard

    2014-01-01

    Computer-based assessment can provide new insights into behavioral processes of task completion that cannot be uncovered by paper-based instruments. Time presents a major characteristic of the task completion process. Psychologically, time on task has 2 different interpretations, suggesting opposing associations with task outcome: Spending more…

  2. [The application of the concise exposure index to repetitive movement tasks of the upper limbs in various production settings: preliminary experience and validation].

    PubMed

    Colombini, D; Occhipinti, E

    1996-01-01

    A summary of eight investigations is presented, which were carried out using standardised methods, for the purpose of quantifying exposure to tasks involving repetitive movements of the upper limbs, as well as quantifying the prevalence of Work Related Musculo Skeletal Disorders of the upper limbs in groups of exposed workers. A total of 462 exposed workers were examined, and the study also took into account the data pertaining to a matched control group comprising 749 workers not exposed to any specific occupational risk. Regarding the quantification of exposure to increased risk, use was made of a Concise Index (OCRA), proposed by the Authors in a previous publication. The data resulting from the eight investigations were used for the study of measurements and models of association among the exposure variables (mainly represented by the OCRA index), as well as the effect variables represented by the prevalence of the various WMSDs of the upper limbs taken both individually and jointly. Significant associations were reported between the OCRA index and an effect indicator represented by the prevalence of all the WSMDs of the upper limbs, calculated on the number of upper limbs at risk. When a logarithmic conversion of the relative exposure (OCRA) and injury indices was carried out, a simple linear regression model resulted which seems to provide a satisfactory predictive performance of the risk of WMSDs of the upper limbs, based on the exposure index. The study confirmed the efficacy of various other models designed to predict effects based on multiple linear regression functions, in which the independent variables are represented by both the OCRA exposure index and by parameters relative to the breakdown by sex and age of the groups of exposed workers.

  3. An equation to predict maximum acceptable loads for repetitive tasks based on duty cycle: evaluation with lifting and lowering tasks.

    PubMed

    Potvin, Jim R

    2012-01-01

    Recently, an equation was developed to predict maximal acceptable effort (MAE) for repetitive tasks based on the product of task frequency and effort duration (ie. duty cycle). This equation has been shown to closely match data from psychophysical studies of the upper extremities. In the current paper, the applicability of this equation was tested on lifting and lowering data from Snook and Ciriello (1991) and was found to fit closely, even at very low duty cycles.

  4. Local search to improve coordinate-based task mapping

    DOE PAGES

    Balzuweit, Evan; Bunde, David P.; Leung, Vitus J.; ...

    2015-10-31

    We present a local search strategy to improve the coordinate-based mapping of a parallel job’s tasks to the MPI ranks of its parallel allocation in order to reduce network congestion and the job’s communication time. The goal is to reduce the number of network hops between communicating pairs of ranks. Our target is applications with a nearest-neighbor stencil communication pattern running on mesh systems with non-contiguous processor allocation, such as Cray XE and XK Systems. Utilizing the miniGhost mini-app, which models the shock physics application CTH, we demonstrate that our strategy reduces application running time while also reducing the runtimemore » variability. Furthermore, we further show that mapping quality can vary based on the selected allocation algorithm, even between allocation algorithms of similar apparent quality.« less

  5. Local search to improve coordinate-based task mapping

    SciTech Connect

    Balzuweit, Evan; Bunde, David P.; Leung, Vitus J.; Finley, Austin; Lee, Alan C. S.

    2015-10-31

    We present a local search strategy to improve the coordinate-based mapping of a parallel job’s tasks to the MPI ranks of its parallel allocation in order to reduce network congestion and the job’s communication time. The goal is to reduce the number of network hops between communicating pairs of ranks. Our target is applications with a nearest-neighbor stencil communication pattern running on mesh systems with non-contiguous processor allocation, such as Cray XE and XK Systems. Utilizing the miniGhost mini-app, which models the shock physics application CTH, we demonstrate that our strategy reduces application running time while also reducing the runtime variability. Furthermore, we further show that mapping quality can vary based on the selected allocation algorithm, even between allocation algorithms of similar apparent quality.

  6. Repeating Input-Based Tasks with Young Beginner Learners

    ERIC Educational Resources Information Center

    Shintani, Natsuko

    2012-01-01

    The study reported in this article investigated task-repetition with young Japanese children. Fifteen children with no prior knowledge of English completed a communicative listening task that was designed to introduce new vocabulary. The same task was repeated nine times over five weeks. In line with Allwright's (1984) claim that "interaction…

  7. The Task-Based Approach: Some Questions and Suggestions

    ERIC Educational Resources Information Center

    Littlewood, William

    2004-01-01

    This article first addresses the question of what tasks are. It suggests that rather than accept the common "communicative" definition, we should return to a broader definition and then focus on key dimensions that distinguish (from the learner's perspective) different types of task, notably degrees of task involvement and degrees of focus on form…

  8. Enabling task-based information prioritization via semantic web encodings

    NASA Astrophysics Data System (ADS)

    Michaelis, James R.

    2016-05-01

    Modern Soldiers rely upon accurate and actionable information technology to achieve mission objectives. While increasingly rich sensor networks for Areas of Operation (AO) can offer many directions for aiding Soldiers, limitations are imposed by current tactical edge systems on the rate that content can be transmitted. Furthermore, mission tasks will often require very specific sets of information which may easily be drowned out by other content sources. Prior research on Quality and Value of Information (QoI/VoI) has aimed to define ways to prioritize information objects based on their intrinsic attributes (QoI) and perceived value to a consumer (VoI). As part of this effort, established ranking approaches for obtaining Subject Matter Expert (SME) recommendations, such as the Analytic Hierarchy Process (AHP) have been considered. However, limited work has been done to tie Soldier context - such as descriptions of their mission and tasks - back to intrinsic attributes of information objects. As a first step toward addressing the above challenges, this work introduces an ontology-backed approach - rooted in Semantic Web publication practices - for expressing both AHP decision hierarchies and corresponding SME feedback. Following a short discussion on related QoI/VoI research, an ontology-based data structure is introduced for supporting evaluation of Information Objects, using AHP rankings designed to facilitate information object prioritization. Consistent with alternate AHP approaches, prioritization in this approach is based on pairwise comparisons between Information Objects with respect to established criteria, as well as on pairwise comparison of the criteria to assess their relative importance. The paper concludes with a discussion of both ongoing and future work.

  9. Language Tasks Using Touch Screen and Mobile Technologies: Reconceptualizing Task-Based CALL for Young Language Learners

    ERIC Educational Resources Information Center

    Pellerin, Martine

    2014-01-01

    This article examines how the use of mobile technologies (iPods and tablets) in language classrooms contributes to redesigning task-based approaches for young language learners. The article is based on a collaborative action research (CAR) project in Early French Immersion classrooms in the province of Alberta, Canada. The data collection included…

  10. Task- and Time-Dependent Weighting Factors in a Retrospective Exposure Assessment of Chemical Laboratory Workers

    SciTech Connect

    Scott A. Henn, David F. Utterback, Kathleen M. Waters, Andrea M. Markey, William G. Tankersley

    2007-02-01

    Results are reported from a chemical exposure assessment that was conducted for a cohort mortality study of 6157 chemical laboratory workers employed between 1943 and 1998 at four Department of Energy sites in Oak Ridge, Tenn., and Aiken, S.C.

  11. Early Childhood Household Smoke Exposure Predicts Less Task-Oriented Classroom Behavior at Age 10

    ERIC Educational Resources Information Center

    Pagani, Linda S.; Fitzpatrick, Caroline

    2016-01-01

    Secondhand tobacco smoke is considered a developmental neurotoxicant especially given underdeveloped vital systems in young children. An ecological test of its negative influence on brain development can be made by examining the prospective association between early childhood household smoke exposure and later classroom behavior. Using a…

  12. Teachers' and Learners' Reactions to a Task-Based EFL Course in Thailand

    ERIC Educational Resources Information Center

    McDonough, Kim; Chaikitmongkol, Wanpen

    2007-01-01

    Although many studies have described the L2 learning opportunities created by individual tasks, considerably less research has investigated task-based syllabi and courses (Bruton, 2002; Candlin, 2001; Ellis, 2003; Skehan, 2003). This case study investigated teachers' and learners' reactions to a task-based EFL course at a Thai university. A team…

  13. Internalizing versus Externalizing Control: Different Ways to Perform a Time-Based Prospective Memory Task

    ERIC Educational Resources Information Center

    Huang, Tracy; Loft, Shayne; Humphreys, Michael S.

    2014-01-01

    "Time-based prospective memory" (PM) refers to performing intended actions at a future time. Participants with time-based PM tasks can be slower to perform ongoing tasks (costs) than participants without PM tasks because internal control is required to maintain the PM intention or to make prospective-timing estimates. However, external…

  14. Creative Disruption: A Task-Based Approach to Engaging With Original Works of Art

    ERIC Educational Resources Information Center

    Walker, Keith; Smith, Liz

    2004-01-01

    This paper examines the value of a task-based approach to engaging with original works of art and focuses in particular upon the experiences of a group of PGCE Art and Design trainees when they visited an exhibition entitled, Air Guitar: Art Reconsidering Rock Music, to carry out given tasks. The extent to which a task-based approach might…

  15. Task Complexity, Focus on L2 Constructions, and Individual Differences: A Classroom-Based Study

    ERIC Educational Resources Information Center

    Revesz, Andrea

    2011-01-01

    Motivated by cognitive-interactionist frameworks for task-based learning, this study explores whether task complexity affects the extent to which learners focus on form-meaning connections during task-based work in a classroom setting, and whether this relationship is modulated by 3 individual difference factors--linguistic self-confidence,…

  16. Young Foreign Language Learners' Interactions during Task-Based Paired Assessments

    ERIC Educational Resources Information Center

    Butler, Yuko Goto; Zeng, Wei

    2014-01-01

    Despite the popularity of task-based language teaching (TBLT) in foreign language (FL) education at elementary school, it remains unclear how young learners' FL abilities can best be evaluated with tasks. The present study seeks to understand developmental differences in interactions among elementary-school students during task-based language…

  17. Solution of the Applied Task to Determine Total Exposure for Mechanical Engineering Workers

    NASA Astrophysics Data System (ADS)

    Medvedeva, O. V.; Orlova, K. N.; Borovikov, I. F.

    2016-08-01

    In everyday life, people repeatedly exposed to ionizing radiation. Radiation sources is as natural background radiation due to the natural radioactivity of the earth, cosmic and solar radiation and artificial emitters in enterprise engineering. Therefore, the determination of the total human exposure in engineering industry will consist of a variety of factors will be strictly defined for a specific person, and undoubtedly true. Neural network technology can completely resolve this problem, follow neyroalgoritm presented in this paper.

  18. Task-Based Design of Fluence Field Modulation in CT for Model-Based Iterative Reconstruction.

    PubMed

    Gang, Grace J; Siewerdsen, Jeffrey H; Stayman, J Webster

    2016-07-01

    A task-driven imaging framework for prospective fluence field modulation (FFM) is developed in this paper. The design approach uses a system model that includes a parameterized FFM acquisition and model-based iterative reconstruction (MBIR) for image formation. Using prior anatomical knowledge (e.g. from a low-dose 3D scout image), accurate predictions of spatial resolution and noise as a function of FFM are integrated into a task-based objective function. Specifically, detectability index (d'), a common metric for task-based image quality assessment, is computed for a specific formulation of the imaging task. To optimize imaging performance in across an image volume, a maximin objective function was adopted to maximize the minimum detectability index for many locations sampled throughout the volume. To reduce the dimensionality, FFM patterns were represented using wavelet bases, the coefficients of which were optimized using the covariance matrix adaptation evolutionary strategy (CMA-ES) algorithm. The optimization was performed for a mid-frequency discrimination task involving a cluster of micro-calcifications in an abdomen phantom. The task-driven design yielded FFM patterns that were significantly different from traditional strategies proposed for FBP reconstruction. In addition to a higher minimum d' consistent with the objective function, the task-driven approach also improved d' to a greater extent over a larger area of the phantom. Results from this work suggests that FFM strategies suitable for FBP reconstruction need to be reevaluated in the context of MBIR and that a task-driven imaging framework provides a promising approach for such optimization.

  19. Personal exposure assessment to particulate metals using a paper-based analytical device

    NASA Astrophysics Data System (ADS)

    Cate, David; Volckens, John; Henry, Charles

    2013-03-01

    The development of a paper-based analytical device (PAD) for assessing personal exposure to particulate metals will be presented. Human exposure to metal aerosols, such as those that occur in the mining, construction, and manufacturing industries, has a significant impact on the health of our workforce, costing an estimated $10B in the U.S and causing approximately 425,000 premature deaths world-wide each year. Occupational exposure to particulate metals affects millions of individuals in manufacturing, construction (welding, cutting, blasting), and transportation (combustion, utility maintenance, and repair services) industries. Despite these effects, individual workers are rarely assessed for their exposure to particulate metals, due mainly to the high cost and effort associated with personal exposure measurement. Current exposure assessment methods for particulate metals call for an 8-hour filter sample, after which time, the filter sample is transported to a laboratory and analyzed by inductively-coupled plasma (ICP). The time from sample collection to reporting is typically weeks and costs several hundred dollars per sample. To exacerbate the issue, method detection limits suffer because of sample dilution during digestion. The lack of sensitivity hampers task-based exposure assessment, for which sampling times may be tens of minutes. To address these problems, and as a first step towards using microfluidics for personal exposure assessment, we have developed PADs for measurement of Pb, Cd, Cr, Fe, Ni, and Cu in aerosolized particulate matter.

  20. The measurement and facilitation of cooperative task performance. [reactions of humans to stress exposure

    NASA Technical Reports Server (NTRS)

    Hutchinson, R. R.

    1975-01-01

    Experiments were conducted to determine under what conditions jaw clenching will occur in humans as a response to stress exposure. The method for measuring reactions to stress involves a series of electrical recordings of the masseter and temporalis muscles. A high fixed-ratio response requirement in the first series of experiments shows that jaw clenching in humans occurs in situations analogous to those which produce biting in infrahuman subjects. In the second series, reduction in the amounts of money recieved by subjects is shown to cause increases in the jaw clench response and other negative effect motor behaviors. The third series demonstrates that perception of more favorable conditions existing for another person can increase anger and hostility in the subject.

  1. Boys, not girls, are negatively affected on cognitive tasks by lead exposure: a pilot study.

    PubMed

    Khanna, Maya M

    2015-01-01

    The study described in this article provides behavioral evidence that boys experience the deleterious cognitive effects of lead more than girls do. In fact, girls with elevated blood lead levels (BLLs - 10 μg/dL) performed as well as girls without elevated BLLs on behavioral measures of cognition. This was shown by testing executive function and reading readiness skills of 40 young children (aged three to six years; 23 with elevated blood lead levels, 17 without) residing within a U.S. Environmental Protection Agency-designated lead Superfund site. The results also indicate that elevated BLLs are related to a more pronounced negative impact on executive function than on reading readiness. These findings support recent research on adults indicating that lead exposure is related to atrophy within the prefrontal cortex and other work suggesting that estrogen and estradiol may act as neuroprotectants against the negative impact of neurotoxins.

  2. A task-based quality control metric for digital mammography

    NASA Astrophysics Data System (ADS)

    Maki Bloomquist, A. K.; Mainprize, J. G.; Mawdsley, G. E.; Yaffe, M. J.

    2014-11-01

    A reader study was conducted to tune the parameters of an observer model used to predict the detectability index (dʹ ) of test objects as a task-based quality control (QC) metric for digital mammography. A simple test phantom was imaged to measure the model parameters, namely, noise power spectrum, modulation transfer function and test-object contrast. These are then used in a non-prewhitening observer model, incorporating an eye-filter and internal noise, to predict dʹ. The model was tuned by measuring dʹ of discs in a four-alternative forced choice reader study. For each disc diameter, dʹ was used to estimate the threshold thicknesses for detectability. Data were obtained for six types of digital mammography systems using varying detector technologies and x-ray spectra. A strong correlation was found between measured and modeled values of dʹ, with Pearson correlation coefficient of 0.96. Repeated measurements from separate images of the test phantom show an average coefficient of variation in dʹ for different systems between 0.07 and 0.10. Standard deviations in the threshold thickness ranged between 0.001 and 0.017 mm. The model is robust and the results are relatively system independent, suggesting that observer model dʹ shows promise as a cross platform QC metric for digital mammography.

  3. A Task-Based Language Teaching Approach to the Police Traffic Stop

    ERIC Educational Resources Information Center

    O'Connell, Stephen P.

    2014-01-01

    One possible hurdle to implementing the Task-Based Language Teaching (TBLT) approach is uncertainty about how to turn target tasks into materials that can be used in the classroom. This article discusses the steps taken to create materials for one target task (communicating with a police officer during a traffic stop) in a manner that provides a…

  4. Agricultural Production: Task Analysis for Livestock Production. Competency-Based Education.

    ERIC Educational Resources Information Center

    Henrico County Public Schools, Glen Allen, VA. Virginia Vocational Curriculum Center.

    This task analysis guide is intended to help teachers and administrators develop instructional materials and implement competency-based education in the agricultural production program. Section 1 contains a validated task inventory for the livestock production portion of agricultural production IV and V. Tasks are divided into six duty areas:…

  5. Objective Motion Cueing Criteria Investigation Based on Three Flight Tasks

    NASA Technical Reports Server (NTRS)

    Zaal, Petrus M. T.; Schroeder, Jeffery A.; Chung, William W.

    2015-01-01

    This paper intends to help establish fidelity criteria to accompany the simulator motion system diagnostic test specified by the International Civil Aviation Organization. Twelve air- line transport pilots flew three tasks in the NASA Vertical Motion Simulator under four different motion conditions. The experiment used three different hexapod motion configurations, each with a different tradeoff between motion filter gain and break frequency, and one large motion configuration that utilized as much of the simulator's motion space as possible. The motion condition significantly affected: 1) pilot motion fidelity ratings, and sink rate and lateral deviation at touchdown for the approach and landing task, 2) pilot motion fidelity ratings, roll deviations, maximum pitch rate, and number of stick shaker activations in the stall task, and 3) heading deviation after an engine failure in the takeoff task. Significant differences in pilot-vehicle performance were used to define initial objective motion cueing criteria boundaries. These initial fidelity boundaries show promise but need refinement.

  6. Asthma and exposure to cleaning products - a European Academy of Allergy and Clinical Immunology task force consensus statement.

    PubMed

    Siracusa, A; De Blay, F; Folletti, I; Moscato, G; Olivieri, M; Quirce, S; Raulf-Heimsoth, M; Sastre, J; Tarlo, S M; Walusiak-Skorupa, J; Zock, J-P

    2013-12-01

    Professional and domestic cleaning is associated with work-related asthma (WRA). This position paper reviews the literature linking exposure to cleaning products and the risk of asthma and focuses on prevention. Increased risk of asthma has been shown in many epidemiological and surveillance studies, and several case reports describe the relationship between exposure to one or more cleaning agents and WRA. Cleaning sprays, bleach, ammonia, disinfectants, mixing products, and specific job tasks have been identified as specific causes and/or triggers of asthma. Because research conclusions and policy suggestions have remained unheeded by manufactures, vendors, and commercial cleaning companies, it is time for a multifaceted intervention. Possible preventive measures encompass the following: substitution of cleaning sprays, bleach, and ammonia; minimizing the use of disinfectants; avoidance of mixing products; use of respiratory protective devices; and worker education. Moreover, we suggest the education of unions, consumer, and public interest groups to encourage safer products. In addition, information activities for the general population with the purpose of improving the knowledge of professional and domestic cleaners regarding risks and available preventive measures and to promote strict collaboration between scientific communities and safety and health agencies are urgently needed.

  7. Embedding Task-Based Neural Models into a Connectome-Based Model of the Cerebral Cortex

    PubMed Central

    Ulloa, Antonio; Horwitz, Barry

    2016-01-01

    A number of recent efforts have used large-scale, biologically realistic, neural models to help understand the neural basis for the patterns of activity observed in both resting state and task-related functional neural imaging data. An example of the former is The Virtual Brain (TVB) software platform, which allows one to apply large-scale neural modeling in a whole brain framework. TVB provides a set of structural connectomes of the human cerebral cortex, a collection of neural processing units for each connectome node, and various forward models that can convert simulated neural activity into a variety of functional brain imaging signals. In this paper, we demonstrate how to embed a previously or newly constructed task-based large-scale neural model into the TVB platform. We tested our method on a previously constructed large-scale neural model (LSNM) of visual object processing that consisted of interconnected neural populations that represent, primary and secondary visual, inferotemporal, and prefrontal cortex. Some neural elements in the original model were “non-task-specific” (NS) neurons that served as noise generators to “task-specific” neurons that processed shapes during a delayed match-to-sample (DMS) task. We replaced the NS neurons with an anatomical TVB connectome model of the cerebral cortex comprising 998 regions of interest interconnected by white matter fiber tract weights. We embedded our LSNM of visual object processing into corresponding nodes within the TVB connectome. Reciprocal connections between TVB nodes and our task-based modules were included in this framework. We ran visual object processing simulations and showed that the TVB simulator successfully replaced the noise generation originally provided by NS neurons; i.e., the DMS tasks performed with the hybrid LSNM/TVB simulator generated equivalent neural and fMRI activity to that of the original task-based models. Additionally, we found partial agreement between the functional

  8. Embedding Task-Based Neural Models into a Connectome-Based Model of the Cerebral Cortex.

    PubMed

    Ulloa, Antonio; Horwitz, Barry

    2016-01-01

    A number of recent efforts have used large-scale, biologically realistic, neural models to help understand the neural basis for the patterns of activity observed in both resting state and task-related functional neural imaging data. An example of the former is The Virtual Brain (TVB) software platform, which allows one to apply large-scale neural modeling in a whole brain framework. TVB provides a set of structural connectomes of the human cerebral cortex, a collection of neural processing units for each connectome node, and various forward models that can convert simulated neural activity into a variety of functional brain imaging signals. In this paper, we demonstrate how to embed a previously or newly constructed task-based large-scale neural model into the TVB platform. We tested our method on a previously constructed large-scale neural model (LSNM) of visual object processing that consisted of interconnected neural populations that represent, primary and secondary visual, inferotemporal, and prefrontal cortex. Some neural elements in the original model were "non-task-specific" (NS) neurons that served as noise generators to "task-specific" neurons that processed shapes during a delayed match-to-sample (DMS) task. We replaced the NS neurons with an anatomical TVB connectome model of the cerebral cortex comprising 998 regions of interest interconnected by white matter fiber tract weights. We embedded our LSNM of visual object processing into corresponding nodes within the TVB connectome. Reciprocal connections between TVB nodes and our task-based modules were included in this framework. We ran visual object processing simulations and showed that the TVB simulator successfully replaced the noise generation originally provided by NS neurons; i.e., the DMS tasks performed with the hybrid LSNM/TVB simulator generated equivalent neural and fMRI activity to that of the original task-based models. Additionally, we found partial agreement between the functional

  9. SKE/BKE task-based methodology for calculating Hotelling observer SNR in mammography

    NASA Astrophysics Data System (ADS)

    Liu, Haimo; Kyprianou, Iacovos S.; Badano, Aldo; Myers, Kyle J.; Jennings, Robert J.; Park, Subok; Kaczmarek, Richard V.; Chakrabarti, Kish

    2009-02-01

    A common method for evaluating projection mammography is Contrast-Detail (CD) curves derived from the CD phantom for Mammography (CDMAM). The CD curves are derived either by human observers, or by automated readings. Both methods have drawbacks which limit their reliability. The human based reading is significantly affected by reader variability, reduced precision and bias. On the other hand, the automated methods suffer from limited statistics. The purpose of this paper is to develop a simple and reliable methodology for the evaluation of mammographic imaging systems using the Signal Known Exactly/Background Known Exactly (SKE/BKE) detection task for signals relevant to mammography. In this paper, we used the spatial definition of the ideal, linear (Hotelling) observer to calculate the task-specific SNR for mammography and discussed the results. The noise covariance matrix as well as the detector response H matrix of the imaging system were estimated and used to calculate the SNRSKEBKE for the simulated discs of the CDMAM. The SNR as a function of exposure, disc diameter and thickness were calculated.

  10. Regular Exercise Enhances Task-Based Industriousness in Laboratory Rats

    PubMed Central

    Laurence, Nicholas C.; Labuschagne, Lisa G.; Lura, Brent G.; Hillman, Kristin L.

    2015-01-01

    Individuals vary greatly in their willingness to select and persist in effortful tasks, even when high-effort will knowingly result in high-reward. Individuals who select and successively complete effortful, goal-directed tasks can be described as industrious. Trying to increase one’s industriousness is desirable from a productivity standpoint, yet intrinsically challenging given that effort expenditure is generally aversive. Here we show that in laboratory rats, a basic physical exercise regimen (20 min/day, five days/week) is sufficient to increase industriousness across a battery of subsequent testing tasks. Exercised rats outperformed their non-exercised counterparts in tasks designed to tax effort expenditure, strategic decision-making, problem solving and persistence. These increases in performance led to quicker reward obtainment and greater reward gain over time, and could not be accounted for simply by increased locomotor activity. Our results suggest that a basic exercise regimen can enhance effortful goal-directed behaviour in goal-directed tasks, which highlights a potential productivity benefit of staying physically active. PMID:26083255

  11. Opportunity-to-Learn Context-Based Tasks Provided by Mathematics Textbooks

    ERIC Educational Resources Information Center

    Wijaya, Ariyadi; van den Heuvel-Panhuizen, Marja; Doorman, Michiel

    2015-01-01

    Based on the findings of an error analysis revealing that Indonesian ninth- and tenth-graders had difficulties in solving context-based tasks, we investigated the opportunity-to-learn offered by Indonesian textbooks for solving context-based mathematics tasks and the relation of this opportunity-to-learn to students' difficulties in solving these…

  12. The evaluation and quantification of respirable coal and silica dust concentrations: a task-based approach.

    PubMed

    Grové, T; Van Dyk, T; Franken, A; Du Plessis, J

    2014-01-01

    Silicosis and coal worker's pneumoconiosis are serious occupational respiratory diseases associated with the coal mining industry and the inhalation of respirable dusts containing crystalline silica. The purpose of this study (funded by the Mine Health and Safety Council of South Africa) was to evaluate the individual contributions of underground coal mining tasks to the respirable dust and respirable silica dust concentrations in an underground section by sampling the respirable dust concentrations at the intake and return of each task. The identified tasks were continuous miner (CM) cutting, construction, transfer of coal, tipping, and roof bolting. The respirable dust-generating hierarchy of the tasks from highest to lowest was: transfer of coal > CM right cutting > CM left cutting > CM face cutting > construction > roof bolting > tipping; and for respirable silica dust: CM left cutting > construction > transfer of coal > CM right cutting. Personal exposure levels were determined by sampling the exposures of workers performing tasks in the section. Respirable dust concentrations and low concentrations of respirable silica dust were found at the intake air side of the section, indicating that air entering the section is already contaminated. The hierarchy for personal respirable dust exposures was as follows, from highest to lowest: CM operator > cable handler > miner > roof bolt operator > shuttle car operator, and for respirable silica dust: shuttle car operator > CM operator > cable handler > roof bolt operator > miner. Dust control methods to lower exposures should include revision of the position of workers with regard to the task performed, positioning of the tasks with regard to the CM cutting, and proper use of the line curtains to direct ventilation appropriately. The correct use of respiratory protection should also be encouraged.

  13. Design and Analysis in Task-Based Language Assessment.

    ERIC Educational Resources Information Center

    Mislevy, Robert J.; Steinberg, Linda S.; Almond, Russell G.

    2002-01-01

    Introduces a framework for systematizing the design of language performance assessments and explicating the role of tasks within them. Their design outlines fundamental components that must be rationalized and operationalized in order for performance assessment to produce coherent evidence of examinees' abilities. (Author/VWL)

  14. Enhancing Automaticity through Task-Based Language Learning

    ERIC Educational Resources Information Center

    De Ridder, Isabelle; Vangehuchten, Lieve; Gomez, Marta Sesena

    2007-01-01

    In general terms automaticity could be defined as the subconscious condition wherein "we perform a complex series of tasks very quickly and efficiently, without having to think about the various components and subcomponents of action involved" (DeKeyser 2001: 125). For language learning, Segalowitz (2003) characterised automaticity as a…

  15. Human exposure to carbon-based fibrous nanomaterials: A review.

    PubMed

    Guseva Canu, Irina; Bateson, Thomas F; Bouvard, Veronique; Debia, Maximilien; Dion, Chantal; Savolainen, Kai; Yu, Il-Je

    2016-03-01

    In an emerging field of nanotechnologies, assessment of exposure to carbon nanotubes (CNT) and carbon nanofibers (CNF) is an integral component of occupational and environmental epidemiology, risk assessment and management, as well as regulatory actions. The current state of knowledge on exposure to carbon-based fibrous nanomaterials among workers, consumers and general population was studied in frame of the International Agency for Research on Cancer (IARC) Monographs-Volume 111 "Some Nanomaterials and Some Fibres". Completeness and reliability of available exposure data for use in epidemiology and risk assessment were assessed. Occupational exposure to CNT/CNF may be of concern at all stages of the material life-cycle from research through manufacture to use and disposal. Consumer and environmental exposures are only estimated by modeled data. The available information of the final steps of the life-cycle of these materials remains incomplete so far regarding amounts of handled materials and levels of exposure. The quality and amount of information available on the uses and applications of CNT/CNF should be improved to enable quantitative assessment of human exposure to these materials. For that, coordinated effort in producing surveys and exposure inventories based on harmonized strategy of material test, exposure measurement and reporting results is strongly encouraged.

  16. Performance-based workload assessment: Allocation strategy and added task sensitivity

    NASA Technical Reports Server (NTRS)

    Vidulich, Michael A.

    1990-01-01

    The preliminary results of a research program investigating the use of added tasks to evaluate mental workload are reviewed. The focus of the first studies was a reappraisal of the traditional secondary task logic that encouraged the use of low-priority instructions for the added task. It was believed that such low-priority tasks would encourage subjects to split their available resources among the two tasks. The primary task would be assigned all the resources it needed, and any remaining reserve capacity would be assigned to the secondary task. If the model were correct, this approach was expected to combine sensitivity to primary task difficulty with unintrusiveness to primary task performance. The first studies of the current project demonstrated that a high-priority added task, although intrusive, could be more sensitive than the traditional low-priority secondary task. These results suggested that a more appropriate model of the attentional effects associated with added task performance might be based on capacity switching, rather than the traditional optimal allocation model.

  17. Comparison of modeling approaches to prioritize chemicals based on estimates of exposure and exposure potential

    PubMed Central

    Mitchell, Jade; Arnot, Jon A.; Jolliet, Olivier; Georgopoulos, Panos G.; Isukapalli, Sastry; Dasgupta, Surajit; Pandian, Muhilan; Wambaugh, John; Egeghy, Peter; Cohen Hubal, Elaine A.; Vallero, Daniel A.

    2014-01-01

    While only limited data are available to characterize the potential toxicity of over 8 million commercially available chemical substances, there is even less information available on the exposure and use-scenarios that are required to link potential toxicity to human and ecological health outcomes. Recent improvements and advances such as high throughput data gathering, high performance computational capabilities, and predictive chemical inherency methodology make this an opportune time to develop an exposure-based prioritization approach that can systematically utilize and link the asymmetrical bodies of knowledge for hazard and exposure. In response to the US EPA’s need to develop novel approaches and tools for rapidly prioritizing chemicals, a “Challenge” was issued to several exposure model developers to aid the understanding of current systems in a broader sense and to assist the US EPA’s effort to develop an approach comparable to other international efforts. A common set of chemicals were prioritized under each current approach. The results are presented herein along with a comparative analysis of the rankings of the chemicals based on metrics of exposure potential or actual exposure estimates. The analysis illustrates the similarities and differences across the domains of information incorporated in each modeling approach. The overall findings indicate a need to reconcile exposures from diffuse, indirect sources (far-field) with exposures from directly, applied chemicals in consumer products or resulting from the presence of a chemical in a microenvironment like a home or vehicle. Additionally, the exposure scenario, including the mode of entry into the environment (i.e. through air, water or sediment) appears to be an important determinant of the level of agreement between modeling approaches. PMID:23707726

  18. Learner Use of Holistic Language Units in Multimodal, Task-Based Synchronous Computer-Mediated Communication

    ERIC Educational Resources Information Center

    Collentine, Karina

    2009-01-01

    Second language acquisition (SLA) researchers strive to understand the language and exchanges that learners generate in synchronous computer-mediated communication (SCMC). Doughty and Long (2003) advocate replacing open-ended SCMC with task-based language teaching (TBLT) design principles. Since most task-based SCMC (TB-SCMC) research addresses an…

  19. Development and Validation of an Instrument for Evaluating Inquiry-Based Tasks in Science Textbooks

    ERIC Educational Resources Information Center

    Yang, Wenyuan; Liu, Enshan

    2016-01-01

    This article describes the development and validation of an instrument that can be used for content analysis of inquiry-based tasks. According to the theories of educational evaluation and qualities of inquiry, four essential functions that inquiry-based tasks should serve are defined: (1) assisting in the construction of understandings about…

  20. Enhancing Reading Comprehension through Task-Based Writing Activities: An Experimental Study

    ERIC Educational Resources Information Center

    Tilfarlioglu, Filiz Yalcin; Basaran, Suleyman

    2007-01-01

    Task-based learning is a popular topic in ELT/EFL circles nowadays. It is accepted by its proponents as a flourishing method that may replace Communicative Language Learning. However, it can also be seen as an adventure just because there are almost no experimental studies to tackle questions concerning applicability of Task-based Learning. In…

  1. Perceptions of Task-Based Language Teaching: A Study of Iranian EFL Learners

    ERIC Educational Resources Information Center

    Hadi, Atefeh

    2013-01-01

    This paper explored perceptions of Task-Based Language Teaching (TBLT) among a group of Iranian female learners. A sample of 88 English as a Foreign Language (EFL) learners participated in the study. A task-based questionnaire was developed to examine the perceptions of the participants. The results suggested a high level of understanding of TBLT…

  2. An EEG-based mental workload estimator trained on working memory task can work well under simulated multi-attribute task

    PubMed Central

    Ke, Yufeng; Qi, Hongzhi; He, Feng; Liu, Shuang; Zhao, Xin; Zhou, Peng; Zhang, Lixin; Ming, Dong

    2014-01-01

    Mental workload (MW)-based adaptive system has been found to be an effective approach to enhance the performance of human-machine interaction and to avoid human error caused by overload. However, MW estimated from the spontaneously generated electroencephalogram (EEG) was found to be task-specific. In existing studies, EEG-based MW classifier can work well under the task used to train the classifier (within-task) but crash completely when used to classify MW of a task that is similar to but not included in the training data (cross-task). The possible causes have been considered to be the task-specific EEG patterns, the mismatched workload across tasks and the temporal effects. In this study, cross-task performance-based feature selection (FS) and regression model were tried to cope with these challenges, in order to make EEG-based MW estimator trained on working memory tasks work well under a complex simulated multi-attribute task (MAT). The results show that the performance of regression model trained on working memory task and tested on multi-attribute task with the feature subset picked-out were significantly improved (correlation coefficient (COR): 0.740 ± 0.147 and 0.598 ± 0.161 for FS data and validation data respectively) when compared to the performance in the same condition with all features (chance level). It can be inferred that there do exist some MW-related EEG features can be picked out and there are something in common between MW of a relatively simple task and a complex task. This study provides a promising approach to measure MW across tasks. PMID:25249967

  3. An EEG-based mental workload estimator trained on working memory task can work well under simulated multi-attribute task.

    PubMed

    Ke, Yufeng; Qi, Hongzhi; He, Feng; Liu, Shuang; Zhao, Xin; Zhou, Peng; Zhang, Lixin; Ming, Dong

    2014-01-01

    Mental workload (MW)-based adaptive system has been found to be an effective approach to enhance the performance of human-machine interaction and to avoid human error caused by overload. However, MW estimated from the spontaneously generated electroencephalogram (EEG) was found to be task-specific. In existing studies, EEG-based MW classifier can work well under the task used to train the classifier (within-task) but crash completely when used to classify MW of a task that is similar to but not included in the training data (cross-task). The possible causes have been considered to be the task-specific EEG patterns, the mismatched workload across tasks and the temporal effects. In this study, cross-task performance-based feature selection (FS) and regression model were tried to cope with these challenges, in order to make EEG-based MW estimator trained on working memory tasks work well under a complex simulated multi-attribute task (MAT). The results show that the performance of regression model trained on working memory task and tested on multi-attribute task with the feature subset picked-out were significantly improved (correlation coefficient (COR): 0.740 ± 0.147 and 0.598 ± 0.161 for FS data and validation data respectively) when compared to the performance in the same condition with all features (chance level). It can be inferred that there do exist some MW-related EEG features can be picked out and there are something in common between MW of a relatively simple task and a complex task. This study provides a promising approach to measure MW across tasks.

  4. Exposure-Based Cat Modeling, Available data, Advantages, & Limitations

    NASA Astrophysics Data System (ADS)

    Michel, Gero; Hosoe, Taro; Schrah, Mike; Saito, Keiko

    2010-05-01

    This paper discusses the advantages and disadvantages of exposure data for cat-modeling and considers concepts of scale as well as the completeness of data and data scoring using field/model examples. Catastrophe modeling based on exposure data has been considered the panacea for insurance-related cat modeling since the late 1980's. Reasons for this include: • The ability to extend risk modeling to consider data beyond historical losses, • Usability across many relevant scales, • Flexibility in addressing complex structures and policy conditions, and • Ability to assess dependence of risk results on exposure-attributes and exposure-modifiers, such as lines of business, occupancy types, and mitigation features, at any given scale. In order to calculate related risk, monetary exposure is correlated to vulnerabilities that have been calibrated with historical results, plausibility concepts, and/or physical modeling. While exposure based modeling is widely adopted, we also need to be aware of its limitations which include: • Boundaries in our understanding of the distribution of exposure, • Spatial interdependence of exposure patterns and the time-dependence of exposure, • Incomplete availability of loss information to calibrate relevant exposure attributes/structure with related vulnerabilities and losses, • The scale-dependence of vulnerability, • Potential for missing or incomplete communication of assumptions made during model calibration, • Inefficiencies in the aggregation or disaggregation of vulnerabilities, and • Factors which can influence losses other than exposure, vulnerability, and hazard. Although we might assume that the higher the resolution the better, regional model calibration is often limited to lower than street level resolution with higher resolution being achieved by disaggregating results using topographic/roughness features with often loosely constrained and/or varying effects on losses. This suggests that higher accuracy

  5. A Task-Based Design Guide for Command and Control

    DTIC Science & Technology

    2012-06-01

    Decisions & Focal Tasks Cognitive Notional Paper Prototype Walkthrough Cognitive Walkthroughs & Usability Analyses UCD is an HFE best practice...reduce the current burden of user cognition and recall. This approach will enhance the usability of command and control systems, reduce the life cycle...COCOM). With usability issues becoming widespread in the C2 community, there is now an even greater need for UI standardization, which is advanced by

  6. Reliability and validity of self-reported assessment of exposure and outcome variables for manual lifting tasks: a preliminary investigation.

    PubMed

    Yeung, Simon S; Genaidy, Ash M; Karwowski, Waldemar; Leung, P C

    2002-09-01

    The reliability and validity of self-reported assessment of exposure and outcome variables were examined for manual lifting activities among ten physiotherapists. In this study, the participants evaluated the effects of five lifting variables on perceived effort, twice separated by a one-week period. One hundred and sixty-two lifting conditions were evaluated by each subject. The exposure and outcome lifting variables were described in linguistic terms. Intra-class correlation coefficient (ICC(1,1)) analysis revealed a mean value of 0.62 for all lifting activities. The self-reported assessment was cross-validated with the NIOSH lifting index by mapping the linguistic variables into numerical ranges. Moderate correlations (r = 0.54 and 0.53, p<0.01) were obtained between perceived physical exertion/perceived risk and lifting index. The findings of this study provide preliminary indications that human-based methodologies may be further explored on experienced workers.

  7. Evidence-based Sensor Tasking for Space Domain Awareness

    NASA Astrophysics Data System (ADS)

    Jaunzemis, A.; Holzinger, M.; Jah, M.

    2016-09-01

    Space Domain Awareness (SDA) is the actionable knowledge required to predict, avoid, deter, operate through, recover from, and/or attribute cause to the loss and/or degradation of space capabilities and services. A main purpose for SDA is to provide decision-making processes with a quantifiable and timely body of evidence of behavior(s) attributable to specific space threats and/or hazards. To fulfill the promise of SDA, it is necessary for decision makers and analysts to pose specific hypotheses that may be supported or refuted by evidence, some of which may only be collected using sensor networks. While Bayesian inference may support some of these decision making needs, it does not adequately capture ambiguity in supporting evidence; i.e., it struggles to rigorously quantify 'known unknowns' for decision makers. Over the past 40 years, evidential reasoning approaches such as Dempster Shafer theory have been developed to address problems with ambiguous bodies of evidence. This paper applies mathematical theories of evidence using Dempster Shafer expert systems to address the following critical issues: 1) How decision makers can pose critical decision criteria as rigorous, testable hypotheses, 2) How to interrogate these hypotheses to reduce ambiguity, and 3) How to task a network of sensors to gather evidence for multiple competing hypotheses. This theory is tested using a simulated sensor tasking scenario balancing search versus track responsibilities.

  8. A statistical framework for the validation of a population exposure model based on personal exposure data

    NASA Astrophysics Data System (ADS)

    Rodriguez, Delphy; Valari, Myrto; Markakis, Konstantinos; Payan, Sébastien

    2016-04-01

    Currently, ambient pollutant concentrations at monitoring sites are routinely measured by local networks, such as AIRPARIF in Paris, France. Pollutant concentration fields are also simulated with regional-scale chemistry transport models such as CHIMERE (http://www.lmd.polytechnique.fr/chimere) under air-quality forecasting platforms (e.g. Prev'Air http://www.prevair.org) or research projects. These data may be combined with more or less sophisticated techniques to provide a fairly good representation of pollutant concentration spatial gradients over urban areas. Here we focus on human exposure to atmospheric contaminants. Based on census data on population dynamics and demographics, modeled outdoor concentrations and infiltration of outdoor air-pollution indoors we have developed a population exposure model for ozone and PM2.5. A critical challenge in the field of population exposure modeling is model validation since personal exposure data are expensive and therefore, rare. However, recent research has made low cost mobile sensors fairly common and therefore personal exposure data should become more and more accessible. In view of planned cohort field-campaigns where such data will be available over the Paris region, we propose in the present study a statistical framework that makes the comparison between modeled and measured exposures meaningful. Our ultimate goal is to evaluate the exposure model by comparing modeled exposures to monitor data. The scientific question we address here is how to downscale modeled data that are estimated on the county population scale at the individual scale which is appropriate to the available measurements. To assess this question we developed a Bayesian hierarchical framework that assimilates actual individual data into population statistics and updates the probability estimate.

  9. A Decision Analytic Approach to Exposure-Based Chemical ...

    EPA Pesticide Factsheets

    The manufacture of novel synthetic chemicals has increased in volume and variety, but often the environmental and health risks are not fully understood in terms of toxicity and, in particular, exposure. While efforts to assess risks have generally been effective when sufficient data are available, the hazard and exposure data necessary to assess risks adequately are unavailable for the vast majority of chemicals in commerce. The US Environmental Protection Agency has initiated the ExpoCast Program to develop tools for rapid chemical evaluation based on potential for exposure. In this context, a model is presented in which chemicals are evaluated based on inherent chemical properties and behaviorally-based usage characteristics over the chemical’s life cycle. These criteria are assessed and integrated within a decision analytic framework, facilitating rapid assessment and prioritization for future targeted testing and systems modeling. A case study outlines the prioritization process using 51 chemicals. The results show a preliminary relative ranking of chemicals based on exposure potential. The strength of this approach is the ability to integrate relevant statistical and mechanistic data with expert judgment, allowing for an initial tier assessment that can further inform targeted testing and risk management strategies. The National Exposure Research Laboratory′s (NERL′s) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in suppor

  10. Where is it? How deaf adolescents complete fact-based internet search tasks.

    PubMed

    Smith, Chad E

    An exploratory study was designed to describe Internet search behaviors of deaf adolescents who used Internet search engines to complete fact-based search tasks. The study examined search behaviors of deaf high school students such as query formation, query modification, Web site identification, and Web site selection. Consisting of two fact-based search tasks, the study was done in four regional day school programs for the deaf. As students conducted two search tasks, they completed task analyses of the selected Web sites and gave reasons for their selections. The research also identified the processes used by deaf students to compensate for limited English reading abilities while navigating search engines results that were typically written well above deaf students' average reading level. The results demonstrated that deaf adolescents were unable to initiate, conduct, analyze, or validate effective Internet searches in response to fact-based search tasks.

  11. Antimicrobial Exposure Assessment Task Force II (AEATF II) Volume 5: Governing Document for a Multi-Year Antimicrobial Chemical Exposure Monitoring Program (interim draft document with changes)

    EPA Pesticide Factsheets

    This document describes the overall scope of the AEATF II program, demonstrates the need for additional human exposure monitoring data and explains the proposed methodology for the exposure monitoring studies proposed for conduct by the AEATF II.

  12. Antimicrobial Exposure Assessment Task Force II (AEATF II) Volume 5: Governing Document for a Multi-Year Antimicrobial Chemical Exposure Monitoring Program (interim draft document)

    EPA Pesticide Factsheets

    Describes the overall scope of the AEATF II program, demonstrates the need for additional human exposure monitoring data and explains the proposed methodology for the exposure monitoring studies proposed for conduct by the AEATF II.

  13. Maintenance Task Data Base for Buildings: Architectural Systems

    DTIC Science & Technology

    1991-05-01

    Unit Description Hours Units I PWU-3-X Remove asphalt shingles 0.65795 100 sq ft 2 PWU-3-I Install one layer 30# felt on wood desk 0.20499 100 sq ft...3 PWU-3-II Install asphalt shingles with adhesive on wood deck, 1.28871 100 sq ft shingles 12 in. x 36 in. with 5 in. exposure *CT-416: Shingles ...new construction, renovate existing facilities). During design, M&R requirements for various types of components, such as built-up or shingle roofs

  14. School-Based Collaborative Teams: An Exploratory Study of Tasks and Activities

    ERIC Educational Resources Information Center

    Phillippo, Kate; Stone, Susan

    2006-01-01

    This study reports findings from a content analysis of the activities and tasks of a school-based problem-solving team. Analyses of observational data collected over the course of five months found that team tasks and activities fell into the following five clusters: (1) needs identification, program development, and planning; (2) intrateam…

  15. Case-Based Tasks in Mathematics Teacher Preparation: What Is Appropriate?

    ERIC Educational Resources Information Center

    Manouchehri, Azita; Almohalwas, Akram

    2008-01-01

    This article describes a framework for selecting and designing case-based tasks suitable for professional development of mathematics teachers in order for such tasks to lead to substantial learning. The authors share an example they designed and used in content courses and give an account of the impact on their work and on students' learning.…

  16. Task-Based Language Teaching: For the State Secondary FL Classroom?

    ERIC Educational Resources Information Center

    Bruton, Anthony

    2005-01-01

    The purpose of this article is to evaluate the applicability of task-based language teaching (TBLT) to state secondary foreign language classes. After discussion of method in general, TBLT is defined and its particularities described. Tasks are assessed as the basis for syllabus and then as the basis for method. In both cases, the proposals are…

  17. Using Heuristic Task Analysis to Create Web-Based Instructional Design Theory

    ERIC Educational Resources Information Center

    Fiester, Herbert R.

    2010-01-01

    The first purpose of this study was to identify procedural and heuristic knowledge used when creating web-based instruction. The second purpose of this study was to develop suggestions for improving the Heuristic Task Analysis process, a technique for eliciting, analyzing, and representing expertise in cognitively complex tasks. Three expert…

  18. Measurement and Evidence of Computer-Based Task Switching and Multitasking by "Net Generation" Students

    ERIC Educational Resources Information Center

    Judd, Terry; Kennedy, Gregor

    2011-01-01

    Logs of on-campus computer and Internet usage were used to conduct a study of computer-based task switching and multitasking by undergraduate medical students. A detailed analysis of over 6000 individual sessions revealed that while a majority of students engaged in both task switching and multitasking behaviours, they did so less frequently than…

  19. "Storyline": A Task-Based Approach for the Young Learner Classroom

    ERIC Educational Resources Information Center

    Ahlquist, Sharon

    2013-01-01

    The Storyline approach is little known in language teaching contexts although it has much in common with task-based education. Learners play the parts of characters in an unfolding narrative, collaborating on tasks in small groups, a method which combines the use of language skills with practical work. A word often used by participants in a…

  20. Task-Based Learning and Language Proficiency in a Business University

    ERIC Educational Resources Information Center

    Newsom-Ray, Amelia Chloe Caroline; Rutter, Sarah Jane

    2016-01-01

    This project adds to the growing body of empirical research focusing on the effects of task-based learning (TBL) on second language acquisition. Through the design and implementation of two business English case studies, in which learning was scaffolded through a sequence of tasks, the authors argue that a TBL approach to language teaching more…

  1. Using Web-Based Exploratory Tasks to Develop Intercultural Competence in a Homogeneous Cultural Environment

    ERIC Educational Resources Information Center

    Stockwell, Esther

    2016-01-01

    This study adapted web-based exploratory tasks using WebQuests as a means of enabling students to understand and reflect on both the target and their own culture. Learners actively used various authentic resources selected to meet their linguistic and cognitive needs to complete the tasks. The aim of this study was to help Japanese university…

  2. Industrial Arts Instructional Tasks/Competencies for Energy and Power. Competency-Based Education.

    ERIC Educational Resources Information Center

    George Mason Univ., Fairfax, VA.

    This instructional task/competency package is designed to help teachers and administrators in developing competency-based instructional materials for an energy and power course. Part 1 contains a description of the industrial arts program and a course description, instructional task/competency list, and content outline for energy and power. The…

  3. Interactive Computer Based Assessment Tasks: How Problem-Solving Process Data Can Inform Instruction

    ERIC Educational Resources Information Center

    Zoanetti, Nathan

    2010-01-01

    This article presents key steps in the design and analysis of a computer based problem-solving assessment featuring interactive tasks. The purpose of the assessment is to support targeted instruction for students by diagnosing strengths and weaknesses at different stages of problem-solving. The first focus of this article is the task piloting…

  4. Balancing Classroom Management with Mathematical Learning: Using Practice-Based Task Design in Mathematics Teacher Education

    ERIC Educational Resources Information Center

    Biza, Irene; Nardi, Elena; Joel, Gareth

    2015-01-01

    In this paper we present the results from a study in which 21 mathematics trainee teachers engage with two practice-based tasks in which classroom management interferes with mathematical learning. We investigate the trainees' considerations when they make decisions in classroom situations and how these tasks can trigger their reflections on the…

  5. Technical Adequacy of the Maze Task for Curriculum-based Measurement of Reading Growth.

    ERIC Educational Resources Information Center

    Shin, Jongho; Deno, Stanley L.; Espin, Christine

    2000-01-01

    A study examined the technical adequacy of curriculum-based measurement for assessing growth in 43 second-graders whose reading performance was measured monthly over the school year with the maze task. Results showed that the maze task had good alternate-form reliability, sensitively reflected improvement of student performance, and revealed…

  6. Frontal Lobe Involvement in a Task of Time-Based Prospective Memory

    ERIC Educational Resources Information Center

    McFarland, Craig P.; Glisky, Elizabeth L.

    2009-01-01

    Time-based prospective memory (PM) has been found to be negatively affected by aging, possibly as a result of declining frontal lobe (FL) function. Despite a clear retrospective component to PM tasks, the medial temporal lobes (MTL) are thought to play only a secondary role in successful task completion. The present study investigated the role of…

  7. Input-Based Tasks and the Acquisition of Vocabulary and Grammar: A Process-Product Study

    ERIC Educational Resources Information Center

    Shintani, Natsuko

    2012-01-01

    The study reported in this article investigated the use of input-based tasks with young, beginner learners of English as a second language by examining both learning outcomes (i.e. acquisition) and the interactions that resulted from implementing the tasks. The participants were 15 learners, aged six, with no experience of second language (L2)…

  8. Autonomous Learning through Task-Based Instruction in Fully Online Language Courses

    ERIC Educational Resources Information Center

    Lee, Lina

    2016-01-01

    This study investigated the affordances for autonomous learning in a fully online learning environment involving the implementation of task-based instruction in conjunction with Web 2.0 technologies. To that end, four-skill-integrated tasks and digital tools were incorporated into the coursework. Data were collected using midterm reflections,…

  9. Attitudes toward Task-Based Language Learning: A Study of College Korean Language Learners

    ERIC Educational Resources Information Center

    Pyun, Danielle Ooyoung

    2013-01-01

    This study explores second/foreign language (L2) learners' attitudes toward task-based language learning (TBLL) and how these attitudes relate to selected learner variables, namely anxiety, integrated motivation, instrumental motivation, and self-efficacy. Ninety-one college students of Korean as a foreign language, who received task-based…

  10. Validation of a novel cognitive bias task based on difference in quantity of reinforcement for assessing environmental enrichment.

    PubMed

    Keen, Heidi A; Nelson, O Lynne; Robbins, Charles T; Evans, Marc; Shepherdson, David J; Newberry, Ruth C

    2014-05-01

    Cognitive bias tasks purport to assess affective states via responses to ambiguous stimuli. We hypothesized that a novel cognitive bias task based on positive reinforcement using quantity differences would detect changes in affect in captive grizzly bears (Ursus arctos horribilis). We trained bears (n = 8) to respond differently (nose or paw touch) to two stimuli (light or dark gray cue cards), with responses counterbalanced across bears. The two cues signaled a small or large food reward, respectively. Responses to ambiguous probe stimuli (i.e., shades of gray) intermediate to the trained stimuli were classified as either 'optimistic,' appropriate for the larger reward, or 'pessimistic,' appropriate for the smaller reward. In Experiment 1, we explored the contrast in reward size necessary to detect a change in response across probe stimuli (large reward, 3 or 6 apple slices: small reward, 1 slice). We observed a change in response across probe stimuli, with no difference in response between reward-value groups, indicating that a contrast of 3:1 apple slices was sufficient to affect responses. In Experiment 2, we investigated cognitive bias after 2.1 h of exposure to enrichment items varying in attractiveness. Results were unaffected by enrichment type or time spent interacting with enrichments, indicating that the task failed to demonstrate criterion validity for comparing mood following exposure to different enrichment items. However, greater time spent pacing prior to testing was associated with 'optimistic' judgments. The data provide some support for use of cognitive bias tasks based on quantity differences in animal welfare assessments involving captive wildlife.

  11. A task-based comparison of two reconstruction algorithms for digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Mahadevan, Ravi; Ikejimba, Lynda C.; Lin, Yuan; Samei, Ehsan; Lo, Joseph Y.

    2014-03-01

    Digital breast tomosynthesis (DBT) generates 3-D reconstructions of the breast by taking X-Ray projections at various angles around the breast. DBT improves cancer detection as it minimizes tissue overlap that is present in traditional 2-D mammography. In this work, two methods of reconstruction, filtered backprojection (FBP) and the Newton-Raphson iterative reconstruction were used to create 3-D reconstructions from phantom images acquired on a breast tomosynthesis system. The task based image analysis method was used to compare the performance of each reconstruction technique. The task simulated a 10mm lesion within the breast containing iodine concentrations between 0.0mg/ml and 8.6mg/ml. The TTF was calculated using the reconstruction of an edge phantom, and the NPS was measured with a structured breast phantom (CIRS 020) over different exposure levels. The detectability index d' was calculated to assess image quality of the reconstructed phantom images. Image quality was assessed for both conventional, single energy and dual energy subtracted reconstructions. Dose allocation between the high and low energy scans was also examined. Over the full range of dose allocations, the iterative reconstruction yielded a higher detectability index than the FBP for single energy reconstructions. For dual energy subtraction, detectability index was maximized when most of the dose was allocated to the high energy image. With that dose allocation, the performance trend for reconstruction algorithms reversed; FBP performed better than the corresponding iterative reconstruction. However, FBP performance varied very erratically with changing dose allocation. Therefore, iterative reconstruction is preferred for both imaging modalities despite underperforming dual energy FBP, as it provides stable results.

  12. Uranium internal exposure evaluation based on urine assay data

    SciTech Connect

    Lawrence, J.N.P.

    1984-09-01

    The difficulties in assessing internal exposures to uranium from urine assay data are described. A simplified application of the ICRP-30 and ICRP Lung Model concepts to the estimation of uranium intake is presented. A discussion follows on the development of a computer code utilizing the ICRP-30-based uranium elimination model with the existing urine assay information. The calculated uranium exposures from 1949 through 1983 are discussed. 13 references, 1 table.

  13. Curriculum-Based Measures for Secondary Students: Utility and Task Specificity of Text-Based Reading and Vocabulary Measures for Predicting Performance on Content-Area Tasks.

    ERIC Educational Resources Information Center

    Espin, Christine A.; Deno, Stanley L.

    1995-01-01

    This study of 121 10th-grade students investigated the criterion-related validity of 2 potential curriculum-based measurements, reading from text and identifying vocabulary meaning, for predicting student performance on content-area study tasks. Correlational and multiple regression techniques found the vocabulary measure to be the stronger…

  14. Drone based measurement system for radiofrequency exposure assessment.

    PubMed

    Joseph, Wout; Aerts, Sam; Vandenbossche, Matthias; Thielens, Arno; Martens, Luc

    2016-03-10

    For the first time, a method to assess radiofrequency (RF) electromagnetic field (EMF) exposure of the general public in real environments with a true free-space antenna system is presented. Using lightweight electronics and multiple antennas placed on a drone, it is possible to perform exposure measurements. This technique will enable researchers to measure three-dimensional RF-EMF exposure patterns accurately in the future and at locations currently difficult to access. A measurement procedure and appropriate measurement settings have been developed. As an application, outdoor measurements are performed as a function of height up to 60 m for Global System for Mobile Communications (GSM) 900 MHz base station exposure. Bioelectromagnetics. © 2016 Wiley Periodicals, Inc.

  15. Distributions of personal VOC exposures: a population-based analysis.

    PubMed

    Jia, Chunrong; D'Souza, Jennifer; Batterman, Stuart

    2008-10-01

    Information regarding the distribution of volatile organic compound (VOC) concentrations and exposures is scarce, and there have been few, if any, studies using population-based samples from which representative estimates can be derived. This study characterizes distributions of personal exposures to ten different VOCs in the U.S. measured in the 1999--2000 National Health and Nutrition Examination Survey (NHANES). Personal VOC exposures were collected for 669 individuals over 2-3 days, and measurements were weighted to derive national-level statistics. Four common exposure sources were identified using factor analyses: gasoline vapor and vehicle exhaust, methyl tert-butyl ether (MBTE) as a gasoline additive, tap water disinfection products, and household cleaning products. Benzene, toluene, ethyl benzene, xylenes chloroform, and tetrachloroethene were fit to log-normal distributions with reasonably good agreement to observations. 1,4-Dichlorobenzene and trichloroethene were fit to Pareto distributions, and MTBE to Weibull distribution, but agreement was poor. However, distributions that attempt to match all of the VOC exposure data can lead to incorrect conclusions regarding the level and frequency of the higher exposures. Maximum Gumbel distributions gave generally good fits to extrema, however, they could not fully represent the highest exposures of the NHANES measurements. The analysis suggests that complete models for the distribution of VOC exposures require an approach that combines standard and extreme value distributions, and that carefully identifies outliers. This is the first study to provide national-level and representative statistics regarding the VOC exposures, and its results have important implications for risk assessment and probabilistic analyses.

  16. Influence of Planning on Students' Language Performance in Task-Based Language Teaching

    ERIC Educational Resources Information Center

    Wang, Yingli

    2008-01-01

    Task-based language teaching (TBLT) is an important second language teaching method. Planning is one of the significant factors in the studies of TBLT. This paper will mainly discuss the influence of planning on students' language performance in TBLT.

  17. Transfer in Rule-Based Category Learning Depends on the Training Task

    PubMed Central

    Kattner, Florian; Cox, Christopher R.; Green, C. Shawn

    2016-01-01

    While learning is often highly specific to the exact stimuli and tasks used during training, there are cases where training results in learning that generalizes more broadly. It has been previously argued that the degree of specificity can be predicted based upon the learning solution(s) dictated by the particular demands of the training task. Here we applied this logic in the domain of rule-based categorization learning. Participants were presented with stimuli corresponding to four different categories and were asked to perform either a category discrimination task (which permits learning specific rule to discriminate two categories) or a category identification task (which does not permit learning a specific discrimination rule). In a subsequent transfer stage, all participants were asked to discriminate stimuli belonging to two of the categories which they had seen, but had never directly discriminated before (i.e., this particular discrimination was omitted from training). As predicted, learning in the category-discrimination tasks tended to be specific, while the category-identification task produced learning that transferred to the transfer discrimination task. These results suggest that the discrimination and identification tasks fostered the acquisition of different category representations which were more or less generalizable. PMID:27764221

  18. Direct and indirect tasks on assessment of dose and time distributions and thresholds of acute radiation exposure.

    PubMed

    Osovets, S V; Azizova, T V; Day, R D; Wald, N; Moseeva, M B

    2012-02-01

    Mathematical methods were developed to construct dose and time distributions and their associated risks and threshold values for lethal and non-lethal effects of acute radiation exposure to include mortality and incidence, prodromal vomiting, and agranulocytosis. A new distribution (T-model) was obtained to describe time parameters of acute radiation syndrome such as the latency period, time to onset of vomiting, and time to initiation of agranulocytosis. Based on the dose and time distributions, the parameter translation method was defined using an orthogonal regression, which allows one to solve for these distributions in the case of acute radiation exposure. The assessment of threshold doses was performed for some effects of acute radiation syndrome: for the latency period, ∼6-8 Gy absorbed dose and ∼0.7-0.9 h time to onset of vomiting; and for incidence (agranulocytosis), ∼2-3 Gy absorbed dose and ∼2-3 h time to onset of vomiting. The obtained new formula for assessment of radiation risk is applicable to the time parameters of acute radiation syndrome.

  19. The fate of task-irrelevant visual motion: perceptual load versus feature-based attention.

    PubMed

    Taya, Shuichiro; Adams, Wendy J; Graf, Erich W; Lavie, Nilli

    2009-11-18

    We tested contrasting predictions derived from perceptual load theory and from recent feature-based selection accounts. Observers viewed moving, colored stimuli and performed low or high load tasks associated with one stimulus feature, either color or motion. The resultant motion aftereffect (MAE) was used to evaluate attentional allocation. We found that task-irrelevant visual features received less attention than co-localized task-relevant features of the same objects. Moreover, when color and motion features were co-localized yet perceived to belong to two distinct surfaces, feature-based selection was further increased at the expense of object-based co-selection. Load theory predicts that the MAE for task-irrelevant motion would be reduced with a higher load color task. However, this was not seen for co-localized features; perceptual load only modulated the MAE for task-irrelevant motion when this was spatially separated from the attended color location. Our results suggest that perceptual load effects are mediated by spatial selection and do not generalize to the feature domain. Feature-based selection operates to suppress processing of task-irrelevant, co-localized features, irrespective of perceptual load.

  20. Risk-based indicators of Canadians’ exposures to environmental carcinogens

    PubMed Central

    2013-01-01

    Background Tools for estimating population exposures to environmental carcinogens are required to support evidence-based policies to reduce chronic exposures and associated cancers. Our objective was to develop indicators of population exposure to selected environmental carcinogens that can be easily updated over time, and allow comparisons and prioritization between different carcinogens and exposure pathways. Methods We employed a risk assessment-based approach to produce screening-level estimates of lifetime excess cancer risk for selected substances listed as known carcinogens by the International Agency for Research on Cancer. Estimates of lifetime average daily intake were calculated using population characteristics combined with concentrations (circa 2006) in outdoor air, indoor air, dust, drinking water, and food and beverages from existing monitoring databases or comprehensive literature reviews. Intake estimates were then multiplied by cancer potency factors from Health Canada, the United States Environmental Protection Agency, and the California Office of Environmental Health Hazard Assessment to estimate lifetime excess cancer risks associated with each substance and exposure pathway. Lifetime excess cancer risks in excess of 1 per million people are identified as potential priorities for further attention. Results Based on data representing average conditions circa 2006, a total of 18 carcinogen-exposure pathways had potential lifetime excess cancer risks greater than 1 per million, based on varying data quality. Carcinogens with moderate to high data quality and lifetime excess cancer risk greater than 1 per million included benzene, 1,3-butadiene and radon in outdoor air; benzene and radon in indoor air; and arsenic and hexavalent chromium in drinking water. Important data gaps were identified for asbestos, hexavalent chromium and diesel exhaust in outdoor and indoor air, while little data were available to assess risk for substances in dust, food

  1. Lunar base surface mission operations. Lunar Base Systems Study (LBSS) task 4.1

    NASA Technical Reports Server (NTRS)

    1987-01-01

    The purpose was to perform an analysis of the surface operations associated with a human-tended lunar base. Specifically, the study defined surface elements and developed mission manifests for a selected base scenario, determined the nature of surface operations associated with this scenario, generated a preliminary crew extravehicular and intravehicular activity (EVA/IVA) time resource schedule for conducting the missions, and proposed concepts for utilizing remotely operated equipment to perform repetitious or hazardous surface tasks. The operations analysis was performed on a 6 year period of human-tended lunar base operation prior to permanent occupancy. The baseline scenario was derived from a modified version of the civil needs database (CNDB) scenario. This scenario emphasizes achievement of a limited set of science and exploration objectives while emplacing the minimum habitability elements required for a permanent base.

  2. Refining the Construct of Classroom-Based Writing-from-Readings Assessment: The Role of Task Representation

    ERIC Educational Resources Information Center

    Wolfersberger, Mark

    2013-01-01

    This article argues that task representation should be considered as part of the construct of classroom-based academic writing. Task representation is a process that writers move through when creating a unique mental model of the requirements for each new writing task they encounter. Writers' task representations evolve throughout the composing…

  3. Multi-robot task allocation based on two dimensional artificial fish swarm algorithm

    NASA Astrophysics Data System (ADS)

    Zheng, Taixiong; Li, Xueqin; Yang, Liangyi

    2007-12-01

    The problem of task allocation for multiple robots is to allocate more relative-tasks to less relative-robots so as to minimize the processing time of these tasks. In order to get optimal multi-robot task allocation scheme, a twodimensional artificial swarm algorithm based approach is proposed in this paper. In this approach, the normal artificial fish is extended to be two dimension artificial fish. In the two dimension artificial fish, each vector of primary artificial fish is extended to be an m-dimensional vector. Thus, each vector can express a group of tasks. By redefining the distance between artificial fish and the center of artificial fish, the behavior of two dimension fish is designed and the task allocation algorithm based on two dimension artificial swarm algorithm is put forward. At last, the proposed algorithm is applied to the problem of multi-robot task allocation and comparer with GA and SA based algorithm is done. Simulation and compare result shows the proposed algorithm is effective.

  4. Exposure-based validation list for developmental toxicity screening assays.

    PubMed

    Daston, George P; Beyer, Bruce K; Carney, Edward W; Chapin, Robert E; Friedman, Jan M; Piersma, Aldert H; Rogers, John M; Scialli, Anthony R

    2014-12-01

    Validation of alternative assays requires comparison of the responses to toxicants in the alternative assay with in vivo responses. Chemicals have been classified as "positive" or "negative" in vivo, despite the fact that developmental toxicity is conditional on magnitude of exposure. We developed a list of positive and negative developmental exposures, with exposure defined by toxicokinetic data, specifically maternal plasma Cmax . We selected a series of 20 chemicals that caused developmental toxicity and for which there were appropriate toxicokinetic data. Where possible, we used the same chemical for both positive and negative exposures, the positive being the Cmax at a dose level that produced significant teratogenicity or embryolethality, the negative being the Cmax at a dose level not causing developmental toxicity. It was not possible to find toxicokinetic data at the no-effect level for all positive compounds, and the negative exposure list contains Cmax values for some compounds that do not have developmental toxicity up to the highest dose level tested. This exposure-based reference list represents a fundamentally different approach to the evaluation of alternative tests and is proposed as a step toward application of alternative tests in quantitative risk assessment.

  5. The preliminary Long Duration Exposure Facility (LDEF) materials data base

    NASA Technical Reports Server (NTRS)

    Funk, Joan G.; Strickland, John W.; Davis, John M.

    1992-01-01

    A preliminary Long Duration Exposure Facility (LDEF) Materials Data Base was developed by the LDEF Materials Special Investigation Group (MSIG). The LDEF Materials Data Base is envisioned to eventually contain the wide variety and vast quantity of materials data generated for LDEF. The data is searchable by optical, thermal, and mechanical properties, exposure parameters (such as atomic oxygen flux), and author(s) or principal investigator(s). The LDEF Materials Data Base was incorporated into the Materials and Processes Technical Information System (MAPTIS). MAPTIS is a collection of materials data which was computerized and is available to engineers, designers, and researchers in the aerospace community involved in the design and development of spacecraft and related hardware. This paper describes the LDEF Materials Data Base and includes step-by-step example searches using the data base. Information on how to become an authorized user of the system is included.

  6. Establishing aerosol exposure predictive models based on vibration measurements.

    PubMed

    Soo, Jhy-Charm; Tsai, Perng-Jy; Lee, Shih-Chuan; Lu, Shih-Yi; Chang, Cheng-Ping; Liou, Yuh-When; Shih, Tung-Sheng

    2010-06-15

    This paper establishes particulate exposure predictive models based on vibration measurements under various concrete drilling conditions. The whole study was conducted in an exposure chamber using a full-scale mockup of concrete drilling simulator to simulate six drilling conditions. For each drilling condition, the vibration of the three orthogonal axes (i.e., a(x), a(y), and a(z)) was measured from the hand tool. Particulate exposure concentrations to the total suspended particulate (C(TSP)), PM(10) (C(PM10)), and PM(2.5) (C(PM2.5)) were measured at the downwind side of the drilling simulator. Empirical models for predicting C(TSP), C(PM10) and C(PM2.5) were done based on measured a(x), a(y), and a(z) using the generalized additive model. Good agreement between measured aerosol exposures and vibrations was found with R(2)>0.969. Our results also suggest that a(x) was mainly contributed by the abrasive wear. On the other hand, a(y) and a(z) were mainly contributed by both the impact wear and brittle fracture wear. The approach developed from the present study has the potential to provide a cheaper and convenient method for assessing aerosol exposures from various emission sources, particularly when conducting conventional personal aerosol samplings are not possible in the filed.

  7. Task Group on Assessing the Defense Industrial Base

    DTIC Science & Technology

    2010-01-01

    broader customer base (e.g. domestic agencies). Insourcing is considered by industry to be a “ wild card ” with inconsistent, often confusing guidance and...Much more difficult contracting environment – Also, budgets are under stress – Insourcing is a “ wild card ” that complicates the picture DoD guidance

  8. A Decision Analytic Approach to Exposure-Based Chemical Prioritization

    PubMed Central

    Mitchell, Jade; Pabon, Nicolas; Collier, Zachary A.; Egeghy, Peter P.; Cohen-Hubal, Elaine; Linkov, Igor; Vallero, Daniel A.

    2013-01-01

    The manufacture of novel synthetic chemicals has increased in volume and variety, but often the environmental and health risks are not fully understood in terms of toxicity and, in particular, exposure. While efforts to assess risks have generally been effective when sufficient data are available, the hazard and exposure data necessary to assess risks adequately are unavailable for the vast majority of chemicals in commerce. The US Environmental Protection Agency has initiated the ExpoCast Program to develop tools for rapid chemical evaluation based on potential for exposure. In this context, a model is presented in which chemicals are evaluated based on inherent chemical properties and behaviorally-based usage characteristics over the chemical’s life cycle. These criteria are assessed and integrated within a decision analytic framework, facilitating rapid assessment and prioritization for future targeted testing and systems modeling. A case study outlines the prioritization process using 51 chemicals. The results show a preliminary relative ranking of chemicals based on exposure potential. The strength of this approach is the ability to integrate relevant statistical and mechanistic data with expert judgment, allowing for an initial tier assessment that can further inform targeted testing and risk management strategies. PMID:23940664

  9. Low-level exposure to pulsed 900 MHz microwave radiation does not cause deficits in the performance of a spatial learning task in mice.

    PubMed

    Sienkiewicz, Z J; Blackwell, R P; Haylock, R G; Saunders, R D; Cobb, B L

    2000-04-01

    There is some concern that short-term memory loss or other cognitive effects may be associated with the use of mobile cellular telephones. In this experiment, the effect of repeated, acute exposure to a low intensity 900 MHz radiofrequency (RF) field pulsed at 217 Hz was explored using an appetitively-motivated spatial learning and working memory task. Adult male C57BL/6J mice were exposed under far field conditions in a GTEM cell for 45 min each day for 10 days at an average whole-body specific energy absorption rate (SAR) of 0.05 W/kg. Their performance in an 8-arm radial maze was compared to that of sham-exposed control animals. All behavioral assessments were performed without handlers having knowledge of the exposure status of the animals. Animals were tested in the maze immediately following exposure or after a delay of 15 or 30 min. No significant field-dependent effects on performance were observed in choice accuracy or in total times to complete the task across the experiment. These results suggest that exposure to RF radiation simulating a digital wireless telephone (GSM) signal under the conditions of this experiment does not affect the acquisition of the learned response. Further studies are planned to explore the effects of other SARs on learned behavior. Bioelectromagnetics 21:151-158, 2000. Published 2000 Wiley-Liss, Inc.

  10. Early-life exposure to noise reduces mPFC astrocyte numbers and T-maze alternation/discrimination task performance in adult male rats

    PubMed Central

    Ruvalcaba-Delgadillo, Yaveth; Luquín, Sonia; Ramos-Zúñiga, Rodrigo; Feria-Velasco, Alfredo; González-Castañeda, Rocío Elizabeth; Pérez-Vega, Maria Isabel; Jáuregui-Huerta, Fernando; García-Estrada, Joaquín

    2015-01-01

    In this experiment, we evaluated the long-term effects of noise by assessing both astrocyte changes in medial prefrontal cortex (mPFC) and mPFC-related alternation/discrimination tasks. Twenty-one-day-old male rats were exposed during a period of 15 days to a standardized rats’ audiogram-fitted adaptation of a human noisy environment. We measured serum corticosterone (CORT) levels at the end of the exposure and periodically registered body weight gain. In order to evaluate the long-term effects of this exposure, we assessed the rats’ performance on the T-maze apparatus 3 months later. Astrocyte numbers and proliferative changes in mPFC were also evaluated at this stage. We found that environmental noise (EN) exposure significantly increased serum CORT levels and negatively affected the body weight gain curve. Accordingly, enduring effects of noise were demonstrated on mPFC. The ability to solve alternation/discrimination tasks was reduced, as well as the number of astroglial cells. We also found reduced cytogenesis among the mPFC areas evaluated. Our results support the idea that early exposure to environmental stressors may have long-lasting consequences affecting complex cognitive processes. These results also suggest that glial changes may become an important element behind the cognitive and morphological alterations accompanying the PFC changes seen in some stress-related pathologies. PMID:26168952

  11. Research on multirobot pursuit task allocation algorithm based on emotional cooperation factor.

    PubMed

    Fang, Baofu; Chen, Lu; Wang, Hao; Dai, Shuanglu; Zhong, Qiubo

    2014-01-01

    Multirobot task allocation is a hot issue in the field of robot research. A new emotional model is used with the self-interested robot, which gives a new way to measure self-interested robots' individual cooperative willingness in the problem of multirobot task allocation. Emotional cooperation factor is introduced into self-interested robot; it is updated based on emotional attenuation and external stimuli. Then a multirobot pursuit task allocation algorithm is proposed, which is based on emotional cooperation factor. Combined with the two-step auction algorithm recruiting team leaders and team collaborators, set up pursuit teams, and finally use certain strategies to complete the pursuit task. In order to verify the effectiveness of this algorithm, some comparing experiments have been done with the instantaneous greedy optimal auction algorithm; the results of experiments show that the total pursuit time and total team revenue can be optimized by using this algorithm.

  12. Is Neural Activity Detected by ERP-Based Brain-Computer Interfaces Task Specific?

    PubMed Central

    Wenzel, Markus A.; Almeida, Inês; Blankertz, Benjamin

    2016-01-01

    Objective Brain-computer interfaces (BCIs) that are based on event-related potentials (ERPs) can estimate to which stimulus a user pays particular attention. In typical BCIs, the user silently counts the selected stimulus (which is repeatedly presented among other stimuli) in order to focus the attention. The stimulus of interest is then inferred from the electroencephalogram (EEG). Detecting attention allocation implicitly could be also beneficial for human-computer interaction (HCI), because it would allow software to adapt to the user’s interest. However, a counting task would be inappropriate for the envisaged implicit application in HCI. Therefore, the question was addressed if the detectable neural activity is specific for silent counting, or if it can be evoked also by other tasks that direct the attention to certain stimuli. Approach Thirteen people performed a silent counting, an arithmetic and a memory task. The tasks required the subjects to pay particular attention to target stimuli of a random color. The stimulus presentation was the same in all three tasks, which allowed a direct comparison of the experimental conditions. Results Classifiers that were trained to detect the targets in one task, according to patterns present in the EEG signal, could detect targets in all other tasks (irrespective of some task-related differences in the EEG). Significance The neural activity detected by the classifiers is not strictly task specific but can be generalized over tasks and is presumably a result of the attention allocation or of the augmented workload. The results may hold promise for the transfer of classification algorithms from BCI research to implicit relevance detection in HCI. PMID:27792781

  13. Generic Tasks for Knowledge-Based Problem Solving: Extension and New Directions

    DTIC Science & Technology

    1991-02-01

    will be described. The major results arise from projects that are continuations of the following areas of research: theory building for task...knowledge-based system to a model representing the "complete" domain theory . One approach for representing this knowiedge is to define a functional I...Appendix: A ii implementation not-. In Computational Models of Discovery and Theory Formation, 1990. ~161 P.R. Myers. J.F. Davis, and D. Herman. A task

  14. Behavior-based multi-robot collaboration for autonomous construction tasks

    NASA Technical Reports Server (NTRS)

    Stroupe, Ashley; Huntsberger, Terry; Okon, Avi; Aghazarian, Hrand; Robinson, Matthew

    2005-01-01

    The Robot Construction Crew (RCC) is a heterogeneous multi-robot system for autonomous construction of a structure through assembly of Long components. The two robot team demonstrates component placement into an existing structure in a realistic environment. The task requires component acquisition, cooperative transport, and cooperative precision manipulation. A behavior-based architecture provides adaptability. The RCC approach minimizes computation, power, communication, and sensing for applicability to space-related construction efforts, but the techniques are applicable to terrestrial construction tasks.

  15. Simplified Physics Based Models Research Topical Report on Task #2

    SciTech Connect

    Mishra, Srikanta; Ganesh, Priya

    2014-10-31

    We present a simplified-physics based approach, where only the most important physical processes are modeled, to develop and validate simplified predictive models of CO2 sequestration in deep saline formation. The system of interest is a single vertical well injecting supercritical CO2 into a 2-D layered reservoir-caprock system with variable layer permeabilities. We use a set of well-designed full-physics compositional simulations to understand key processes and parameters affecting pressure propagation and buoyant plume migration. Based on these simulations, we have developed correlations for dimensionless injectivity as a function of the slope of fractional-flow curve, variance of layer permeability values, and the nature of vertical permeability arrangement. The same variables, along with a modified gravity number, can be used to develop a correlation for the total storage efficiency within the CO2 plume footprint. Similar correlations are also developed to predict the average pressure within the injection reservoir, and the pressure buildup within the caprock.

  16. Enhancing exposure-based therapy from a translational research perspective.

    PubMed

    Hofmann, Stefan G

    2007-09-01

    Combining an effective psychological treatment with conventional anxiolytic medication is typically not more effective than unimodal therapy for treating anxiety disorders. However, recent advances in the neuroscience of fear reduction have led to novel approaches for combining psychological therapy and pharmacological agents. Exposure-based treatments in humans partly rely on extinction to reduce the fear response in anxiety disorders. Animal studies have shown that D-cycloserine (DCS), a partial agonist at the glycine recognition site of the glutamatergic N-methyl-D-aspartate receptor facilitates extinction learning. Similarly, recent human trials have shown that DCS enhances fear reduction during exposure therapy of some anxiety disorders. This article discusses the biological and psychological mechanisms of extinction learning and the therapeutic value of DCS as an augmentation strategy for exposure therapy. Areas of future research will be identified.

  17. Co-Constructional Task Analysis: Moving beyond Adult-Based Models to Assess Young Children's Task Performance

    ERIC Educational Resources Information Center

    Lee, Scott Weng Fai

    2013-01-01

    The assessment of young children's thinking competence in task performances has typically followed the novice-to-expert regimen involving models of strategies that adults use when engaged in cognitive tasks such as problem-solving and decision-making. Socio-constructivists argue for a balanced pedagogical approach between the adult and child that…

  18. TESS-based dose-response using pediatric clonidine exposures

    SciTech Connect

    Benson, Blaine E. . E-mail: jebenson@salud.unm.edu; Spyker, Daniel A.; Troutman, William G.; Watson, William A. . E-mail: http://www.aapcc.org/

    2006-06-01

    Objective: The toxic and lethal doses of clonidine in children are unclear. This study was designed to determine whether data from the American Association of Poison Control Centers Toxic Exposure Surveillance System (TESS) could be utilized to determine a dose-response relationship for pediatric clonidine exposure. Methods: 3458 single-substance clonidine exposures in children <6 years of age reported to TESS from January 2000 through December 2003 were examined. Dose ingested, age, and medical outcome were available for 1550 cases. Respiratory arrest cases (n = 8) were classified as the most severe of the medical outcome categories (Arrest, Major, Moderate, Mild, and No effect). Exposures reported as a 'taste or lick' (n = 51) were included as a dose of 1/10 of the dosage form involved. Dose ranged from 0.4 to 1980 (median 13) {mu}g/kg. Weight was imputed based on a quadratic estimate of weight for age. Dose certainty was coded as exact (26% of cases) or not exact (74%). Medical outcome (response) was examined via logistic regression using SAS JMP (release 5.1). Results: The logistic model describing medical outcome (P < 0.0001) included Log dose/kg (P 0.0000) and Certainty (P = 0.045). Conclusion: TESS data can provide the basis for a statistically sound description of dose-response for pediatric clonidine poisoning exposures.

  19. A task-oriented modular and agent-based collaborative design mechanism for distributed product development

    NASA Astrophysics Data System (ADS)

    Liu, Jinfei; Chen, Ming; Wang, Lei; Wu, Qidi

    2014-05-01

    The rapid expansion of enterprises makes product collaborative design (PCD) a critical issue under the distributed heterogeneous environment, but as the collaborative task of large-scale network becomes more complicated, neither unified task decomposition and allocation methodology nor Agent-based network management platform can satisfy the increasing demands. In this paper, to meet requirements of PCD for distributed product development, a collaborative design mechanism based on the thought of modularity and the Agent technology is presented. First, the top-down 4-tier process model based on task-oriented modular and Agent is constructed for PCD after analyzing the mapping relationships between requirements and functions in the collaborative design. Second, on basis of sub-task decomposition for PCD based on a mixed method, the mathematic model of task-oriented modular based on multi-objective optimization is established to maximize the module cohesion degree and minimize the module coupling degree, while considering the module executable degree as a restriction. The mathematic model is optimized and simulated by the modified PSO, and the decomposed modules are obtained. Finally, the Agent structure model for collaborative design is put forward, and the optimism matching Agents are selected by using similarity algorithm to implement different task-modules by the integrated reasoning and decision-making mechanism with the behavioral model of collaborative design Agents. With the results of experimental studies for automobile collaborative design, the feasibility and efficiency of this methodology of task-oriented modular and Agent-based collaborative design in the distributed heterogeneous environment are verified. On this basis, an integrative automobile collaborative R&D platform is developed. This research provides an effective platform for automobile manufacturing enterprises to achieve PCD, and helps to promote product numeralization collaborative R&D and

  20. The relationship between maximal lifting capacity and maximum acceptable lift in strength-based soldiering tasks.

    PubMed

    Savage, Robert J; Best, Stuart A; Carstairs, Greg L; Ham, Daniel J

    2012-07-01

    Psychophysical assessments, such as the maximum acceptable lift, have been used to establish worker capability and set safe load limits for manual handling tasks in occupational settings. However, in military settings, in which task demand is set and capable workers must be selected, subjective measurements are inadequate, and maximal capacity testing must be used to assess lifting capability. The aim of this study was to establish and compare the relationship between maximal lifting capacity and a self-determined tolerable lifting limit, maximum acceptable lift, across a range of military-relevant lifting tasks. Seventy male soldiers (age 23.7 ± 6.1 years) from the Australian Army performed 7 strength-based lifting tasks to determine their maximum lifting capacity and maximum acceptable lift. Comparisons were performed to identify maximum acceptable lift relative to maximum lifting capacity for each individual task. Linear regression was used to identify the relationship across all tasks when the data were pooled. Strong correlations existed between all 7 lifting tasks (rrange = 0.87-0.96, p < 0.05). No differences were found in maximum acceptable lift relative to maximum lifting capacity across all tasks (p = 0.46). When data were pooled, maximum acceptable lift was equal to 84 ± 8% of the maximum lifting capacity. This study is the first to illustrate the strong and consistent relationship between maximum lifting capacity and maximum acceptable lift for multiple single lifting tasks. The relationship developed between these indices may be used to help assess self-selected manual handling capability through occupationally relevant maximal performance tests.

  1. Supporting task-oriented collaboration in human-robot teams using semantic-based path planning

    NASA Astrophysics Data System (ADS)

    Yi, Daqing; Goodrich, Michael A.

    2014-06-01

    Improvements in robot autonomy are changing the human-robot interaction from low-level manipulation to high-level task-based collaboration. For a task-oriented collaboration, a human assigns sub-tasks to robot team members. In this paper, we consider task-oriented collaboration of humans and robots in a cordon and search problem. We focus on a path-planning framework with natural language input. By the semantic elements in a shared mental model, a natural language command can be converted into optimization objectives. We import multi-objective optimization to facilitate modeling the "adverb" elements in natural language commands. Finally, human interactions are involved in the optimization search process in order to guarantee that the found solution correctly reflects the human's intent.

  2. Workflow Modelling and Analysis Based on the Construction of Task Models

    PubMed Central

    Cravo, Glória

    2015-01-01

    We describe the structure of a workflow as a graph whose vertices represent tasks and the arcs are associated to workflow transitions in this paper. To each task an input/output logic operator is associated. Furthermore, we associate a Boolean term to each transition present in the workflow. We still identify the structure of workflows and describe their dynamism through the construction of new task models. This construction is very simple and intuitive since it is based on the analysis of all tasks present on the workflow that allows us to describe the dynamism of the workflow very easily. So, our approach has the advantage of being very intuitive, which is an important highlight of our work. We also introduce the concept of logical termination of workflows and provide conditions under which this property is valid. Finally, we provide a counter-example which shows that a conjecture presented in a previous article is false. PMID:25705713

  3. Genetic algorithm based task reordering to improve the performance of batch scheduled massively parallel scientific applications

    DOE PAGES

    Sankaran, Ramanan; Angel, Jordan; Brown, W. Michael

    2015-04-08

    The growth in size of networked high performance computers along with novel accelerator-based node architectures has further emphasized the importance of communication efficiency in high performance computing. The world's largest high performance computers are usually operated as shared user facilities due to the costs of acquisition and operation. Applications are scheduled for execution in a shared environment and are placed on nodes that are not necessarily contiguous on the interconnect. Furthermore, the placement of tasks on the nodes allocated by the scheduler is sub-optimal, leading to performance loss and variability. Here, we investigate the impact of task placement on themore » performance of two massively parallel application codes on the Titan supercomputer, a turbulent combustion flow solver (S3D) and a molecular dynamics code (LAMMPS). Benchmark studies show a significant deviation from ideal weak scaling and variability in performance. The inter-task communication distance was determined to be one of the significant contributors to the performance degradation and variability. A genetic algorithm-based parallel optimization technique was used to optimize the task ordering. This technique provides an improved placement of the tasks on the nodes, taking into account the application's communication topology and the system interconnect topology. As a result, application benchmarks after task reordering through genetic algorithm show a significant improvement in performance and reduction in variability, therefore enabling the applications to achieve better time to solution and scalability on Titan during production.« less

  4. Genetic algorithm based task reordering to improve the performance of batch scheduled massively parallel scientific applications

    SciTech Connect

    Sankaran, Ramanan; Angel, Jordan; Brown, W. Michael

    2015-04-08

    The growth in size of networked high performance computers along with novel accelerator-based node architectures has further emphasized the importance of communication efficiency in high performance computing. The world's largest high performance computers are usually operated as shared user facilities due to the costs of acquisition and operation. Applications are scheduled for execution in a shared environment and are placed on nodes that are not necessarily contiguous on the interconnect. Furthermore, the placement of tasks on the nodes allocated by the scheduler is sub-optimal, leading to performance loss and variability. Here, we investigate the impact of task placement on the performance of two massively parallel application codes on the Titan supercomputer, a turbulent combustion flow solver (S3D) and a molecular dynamics code (LAMMPS). Benchmark studies show a significant deviation from ideal weak scaling and variability in performance. The inter-task communication distance was determined to be one of the significant contributors to the performance degradation and variability. A genetic algorithm-based parallel optimization technique was used to optimize the task ordering. This technique provides an improved placement of the tasks on the nodes, taking into account the application's communication topology and the system interconnect topology. As a result, application benchmarks after task reordering through genetic algorithm show a significant improvement in performance and reduction in variability, therefore enabling the applications to achieve better time to solution and scalability on Titan during production.

  5. Conducting Task-Based Interviews with Pairs of Children: Consensus, Conflict, Knowledge Construction and Turn Taking

    ERIC Educational Resources Information Center

    Houssart, Jenny; Evens, Hilary

    2011-01-01

    This article explores theoretical and methodological issues associated with task-based interviews conducted with pairs of children. We explore different approaches to interviews from sociological, psychological and subject-based perspectives. Our interviews, concerning mathematical questions and carried out with pairs of 10 and 11-year-olds, are…

  6. Evaluating Tasks for Performance-Based Assessments: Advice for Music Teachers

    ERIC Educational Resources Information Center

    Scott, Sheila

    2004-01-01

    Performance-based assessments allow teachers to systematically observe skills used or demonstrated by students when they create a product, construct a response, or make a presentation (McMillan 2001). These assessments are grounded in performance-based tasks that elicit students' responses in relation to the outcomes of instruction. The criteria…

  7. Meaning-Based Scoring: A Systemic Functional Linguistics Model for Automated Test Tasks

    ERIC Educational Resources Information Center

    Gleason, Jesse

    2014-01-01

    Communicative approaches to language teaching that emphasize the importance of speaking (e.g., task-based language teaching) require innovative and evidence-based means of assessing oral language. Nonetheless, research has yet to produce an adequate assessment model for oral language (Chun 2006; Downey et al. 2008). Limited by automatic speech…

  8. Evaluating TBLT: The Case of a Task-Based Spanish Program

    ERIC Educational Resources Information Center

    González-Lloret, Marta; Nielson, Katharine B.

    2015-01-01

    The need for foreign language education in the US has increased in recent years, and teaching methods based on traditional textbooks are unlikely to meet the real-world needs of current learners. As a response, interest in Language for Specific Purposes programs has grown and so has Task-Based Language Teaching (TBLT) methodology. This article…

  9. Collaborative Scaffolding in Online Task-Based Voice Interactions between Advanced Learners

    ERIC Educational Resources Information Center

    Kenning, Marie-Madeleine

    2010-01-01

    This paper reports some of the findings of a distinctive innovative use of audio-conferencing involving a population (campus-based advanced learners) and a type of application (task-based language learning) that have received little attention to date: the use of Wimba Voice Tools to provide additional opportunities for spoken interactions between…

  10. Predictors of processing-based task performance in bilingual and monolingual children.

    PubMed

    Buac, Milijana; Gross, Megan; Kaushanskaya, Margarita

    2016-01-01

    In the present study we examined performance of bilingual Spanish-English-speaking and monolingual English-speaking school-age children on a range of processing-based measures within the framework of Baddeley's working memory model. The processing-based measures included measures of short-term memory, measures of working memory, and a novel word-learning task. Results revealed that monolinguals outperformed bilinguals on the short-term memory tasks but not the working memory and novel word-learning tasks. Further, children's vocabulary skills and socioeconomic status (SES) were more predictive of processing-based task performance in the bilingual group than the monolingual group. Together, these findings indicate that processing-based tasks that engage verbal working memory rather than short-term memory may be better-suited for diagnostic purposes with bilingual children. However, even verbal working memory measures are sensitive to bilingual children's language-specific knowledge and demographic characteristics, and therefore may have limited clinical utility.

  11. SNUMedinfo at TREC CDS Track 2014: Medical Case-based Retrieval Task

    DTIC Science & Technology

    2014-11-01

    at the TREC Clinical Decision Support track 2014. This task is about medical case- based retrieval. Case description is used as query text . Per each...knowledge-based query expan- sion method for the relevance ranking. Secondly, machine learning classifier based text categorization method is used for the...performance improvements. Keywords: Case-based retrieval, Query expansion, Text categorization, Infor- mation retrieval 1. Introduction In this

  12. Occupational exposure to electric and magnetic fields during tasks at ground or floor level at 110 kV substations in Finland

    PubMed Central

    Korpinen, Leena; Pääkkönen, Rauno

    2016-01-01

    The aim was to investigate occupational exposure to electric and magnetic fields during tasks at ground or floor level at 110 kV substations in Finland and to compare the measured values to Directive 2013/35/EU. Altogether, 347 electric field measurements and 100 magnetic field measurements were performed. The average value of all electric fields was 2.3 kV/m (maximum 6.4 kV/m) and that of magnetic fields was 5.8 µT (maximum 51.0 µT). It can be concluded that the electric and magnetic field exposure at ground or floor level is typically below the low action levels of Directive 2013/35/EU. The transposition of the directive will not create new needs to modify the work practice of the evaluated tasks, which can continue to be performed as before. However, for workers with medical implants, the exposure may be high enough to cause interference. PMID:27075421

  13. Task-based strategy for optimized contrast enhanced breast imaging: Analysis of six imaging techniques for mammography and tomosynthesis

    SciTech Connect

    Ikejimba, Lynda C.; Kiarashi, Nooshin; Ghate, Sujata V.; Samei, Ehsan; Lo, Joseph Y.

    2014-06-15

    Purpose: The use of contrast agents in breast imaging has the capability of enhancing nodule detectability and providing physiological information. Accordingly, there has been a growing trend toward using iodine as a contrast medium in digital mammography (DM) and digital breast tomosynthesis (DBT). Widespread use raises concerns about the best way to use iodine in DM and DBT, and thus a comparison is necessary to evaluate typical iodine-enhanced imaging methods. This study used a task-based observer model to determine the optimal imaging approach by analyzing six imaging paradigms in terms of their ability to resolve iodine at a given dose: unsubtracted mammography and tomosynthesis, temporal subtraction mammography and tomosynthesis, and dual energy subtraction mammography and tomosynthesis. Methods: Imaging performance was characterized using a detectability index d{sup ′}, derived from the system task transfer function (TTF), an imaging task, iodine signal difference, and the noise power spectrum (NPS). The task modeled a 10 mm diameter lesion containing iodine concentrations between 2.1 mg/cc and 8.6 mg/cc. TTF was obtained using an edge phantom, and the NPS was measured over several exposure levels, energies, and target-filter combinations. Using a structured CIRS phantom, d{sup ′} was generated as a function of dose and iodine concentration. Results: For all iodine concentrations and dose, temporal subtraction techniques for mammography and tomosynthesis yielded the highest d{sup ′}, while dual energy techniques for both modalities demonstrated the next best performance. Unsubtracted imaging resulted in the lowest d{sup ′} values for both modalities, with unsubtracted mammography performing the worst out of all six paradigms. Conclusions: At any dose, temporal subtraction imaging provides the greatest detectability, with temporally subtracted DBT performing the highest. The authors attribute the successful performance to excellent cancellation of

  14. Task-based strategy for optimized contrast enhanced breast imaging: Analysis of six imaging techniques for mammography and tomosynthesis

    PubMed Central

    Ikejimba, Lynda C.; Kiarashi, Nooshin; Ghate, Sujata V.; Samei, Ehsan; Lo, Joseph Y.

    2014-01-01

    Purpose: The use of contrast agents in breast imaging has the capability of enhancing nodule detectability and providing physiological information. Accordingly, there has been a growing trend toward using iodine as a contrast medium in digital mammography (DM) and digital breast tomosynthesis (DBT). Widespread use raises concerns about the best way to use iodine in DM and DBT, and thus a comparison is necessary to evaluate typical iodine-enhanced imaging methods. This study used a task-based observer model to determine the optimal imaging approach by analyzing six imaging paradigms in terms of their ability to resolve iodine at a given dose: unsubtracted mammography and tomosynthesis, temporal subtraction mammography and tomosynthesis, and dual energy subtraction mammography and tomosynthesis. Methods: Imaging performance was characterized using a detectability index d′, derived from the system task transfer function (TTF), an imaging task, iodine signal difference, and the noise power spectrum (NPS). The task modeled a 10 mm diameter lesion containing iodine concentrations between 2.1 mg/cc and 8.6 mg/cc. TTF was obtained using an edge phantom, and the NPS was measured over several exposure levels, energies, and target-filter combinations. Using a structured CIRS phantom, d′ was generated as a function of dose and iodine concentration. Results: For all iodine concentrations and dose, temporal subtraction techniques for mammography and tomosynthesis yielded the highest d′, while dual energy techniques for both modalities demonstrated the next best performance. Unsubtracted imaging resulted in the lowest d′ values for both modalities, with unsubtracted mammography performing the worst out of all six paradigms. Conclusions: At any dose, temporal subtraction imaging provides the greatest detectability, with temporally subtracted DBT performing the highest. The authors attribute the successful performance to excellent cancellation of inplane structures and

  15. A Bayesian formulation for auction-based task allocation in heterogeneous multi-agent teams

    NASA Astrophysics Data System (ADS)

    Pippin, Charles E.; Christensen, Henrik

    2011-06-01

    In distributed, heterogeneous, multi-agent teams, agents may have different capabilities and types of sensors. Agents in dynamic environments will need to cooperate in real-time to perform tasks with minimal costs. Some example scenarios include dynamic allocation of UAV and UGV robot teams to possible hurricane survivor locations, search and rescue and target detection. Auction based algorithms scale well because agents generally only need to communicate bid information. In addition, the agents are able to perform their computations in parallel and can operate on local information. Furthermore, it is easy to integrate humans and other vehicle types and sensor combinations into an auction framework. However, standard auction mechanisms do not explicitly consider sensors with varying reliability. The agents sensor qualities should be explicitly accounted. Consider a scenario with multiple agents, each carrying a single sensor. The tasks in this case are to simply visit a location and detect a target. The sensors are of varying quality, with some having a higher probability of target detection. The agents themselves may have different capabilities, as well. The agents use knowledge of their environment to submit cost-based bids for performing each task and an auction is used to perform the task allocation. This paper discusses techniques for including a Bayesian formulation of target detection likelihood into this auction based framework for performing task allocation across multi-agent heterogeneous teams. Analysis and results of experiments with multiple air systems performing distributed target detection are also included.

  16. Toward open sharing of task-based fMRI data: the OpenfMRI project

    PubMed Central

    Poldrack, Russell A.; Barch, Deanna M.; Mitchell, Jason P.; Wager, Tor D.; Wagner, Anthony D.; Devlin, Joseph T.; Cumba, Chad; Koyejo, Oluwasanmi; Milham, Michael P.

    2013-01-01

    The large-scale sharing of task-based functional neuroimaging data has the potential to allow novel insights into the organization of mental function in the brain, but the field of neuroimaging has lagged behind other areas of bioscience in the development of data sharing resources. This paper describes the OpenFMRI project (accessible online at http://www.openfmri.org), which aims to provide the neuroimaging community with a resource to support open sharing of task-based fMRI studies. We describe the motivation behind the project, focusing particularly on how this project addresses some of the well-known challenges to sharing of task-based fMRI data. Results from a preliminary analysis of the current database are presented, which demonstrate the ability to classify between task contrasts with high generalization accuracy across subjects, and the ability to identify individual subjects from their activation maps with moderately high accuracy. Clustering analyses show that the similarity relations between statistical maps have a somewhat orderly relation to the mental functions engaged by the relevant tasks. These results highlight the potential of the project to support large-scale multivariate analyses of the relation between mental processes and brain function. PMID:23847528

  17. Performance of the Rayleigh task based on the posterior probability of tomographic reconstructions

    SciTech Connect

    Hanson, K.M.

    1991-01-01

    We seek the best possible performance of the Rayleigh task in which one must decide whether a perceived object is a pair of Gaussian-blurred points or a blurred line. Two Bayesian reconstruction algorithms are used, the first based on a Gaussian prior-probability distribution with a nonnegativity constraint and the second based on an entropic prior. In both cases, the reconstructions are found that maximize the posterior probability. We compare the performance of the Rayleigh task obtained with two decision variables, the logarithm of the posterior probability ratio and the change in the mean-squared deviation from the reconstruction. The method of evaluation is based on the results of a numerical testing procedure in which the stated discrimination task is carried out on reconstructions of a randomly generated sequence of images. The ability to perform the Rayleigh task is summarized in terms of a discrimination index that is derived from the area under the receiver-operating characteristic (ROC) curve. We find that the use of the posterior probability does not result in better performance of the Rayleigh task than the mean-squared deviation from the reconstruction. 10 refs., 6 figs.

  18. Measuring pilot workload in a moving-base simulator. I Asynchronous secondary choice-reaction task

    NASA Technical Reports Server (NTRS)

    Kantowitz, B. H.; Hart, S. G.; Bortolussi, M. R.

    1983-01-01

    The de facto method for measuring airplane pilot workload is based upon subjective ratings. While researchers agree that such subjective data should be bolstered by using objective behavioral measures, results to date have been mixed. No clear objective technique has surfaced as the metric of choice. It is believed that this difficulty is in part due to neglect of theoretical work in psychology that predicts some of the difficulties that are inherent in a futile search for 'the one and only' best secondary task to measure workload. An initial study that used both subjective ratings and an asynchronous choice-reaction secondary task was conducted to determine if such a secondary task could indeed meet the methodological constraints imposed by current theories of attention. Two variants of a flight scenario were combined with two levels of the secondary task. Appropriate single-task control conditions were also included. Results give grounds for cautious optimism but indicate that future research should use synchronous secondary tasks where possible.

  19. Task fMRI data analysis based on supervised stochastic coordinate coding.

    PubMed

    Lv, Jinglei; Lin, Binbin; Li, Qingyang; Zhang, Wei; Zhao, Yu; Jiang, Xi; Guo, Lei; Han, Junwei; Hu, Xintao; Guo, Christine; Ye, Jieping; Liu, Tianming

    2017-02-20

    Task functional magnetic resonance imaging (fMRI) has been widely employed for brain activation detection and brain network analysis. Modeling rich information from spatially-organized collection of fMRI time series is challenging because of the intrinsic complexity. Hypothesis-driven methods, such as the general linear model (GLM), which regress exterior stimulus from voxel-wise functional brain activity, are limited due to overlooking the complexity of brain activities and the diversity of concurrent brain networks. Recently, sparse representation and dictionary learning methods have attracted increasing interests in task fMRI data analysis. The major advantage of this methodology is its promise in reconstructing concurrent brain networks systematically. However, this data-driven strategy is, to some extent, arbitrary and does not sufficiently utilize the prior information of task design and neuroscience knowledge. To bridge this gap, we here propose a novel supervised sparse representation and dictionary learning framework based on stochastic coordinate coding (SCC) algorithm for task fMRI data analysis, in which certain brain networks are learned with known information such as pre-defined temporal patterns and spatial network patterns, and at the same time other networks are learned automatically from data. Our proposed method has been applied to two independent task fMRI datasets, and qualitative and quantitative evaluations have shown that our method provides a new and effective framework for task fMRI data analysis.

  20. A Consensus-Based Grouping Algorithm for Multi-agent Cooperative Task Allocation with Complex Requirements.

    PubMed

    Hunt, Simon; Meng, Qinggang; Hinde, Chris; Huang, Tingwen

    2014-01-01

    This paper looks at consensus algorithms for agent cooperation with unmanned aerial vehicles. The foundation is the consensus-based bundle algorithm, which is extended to allow multi-agent tasks requiring agents to cooperate in completing individual tasks. Inspiration is taken from the cognitive behaviours of eusocial animals for cooperation and improved assignments. Using the behaviours observed in bees and ants inspires decentralised algorithms for groups of agents to adapt to changing task demand. Further extensions are provided to improve task complexity handling by the agents with added equipment requirements and task dependencies. We address the problems of handling these challenges and improve the efficiency of the algorithm for these requirements, whilst decreasing the communication cost with a new data structure. The proposed algorithm converges to a conflict-free, feasible solution of which previous algorithms are unable to account for. Furthermore, the algorithm takes into account heterogeneous agents, deadlocking and a method to store assignments for a dynamical environment. Simulation results demonstrate reduced data usage and communication time to come to a consensus on multi-agent tasks.

  1. Task-based measures of image quality and their relation to radiation dose and patient risk

    PubMed Central

    Barrett, Harrison H.; Myers, Kyle J.; Hoeschen, Christoph; Kupinski, Matthew A.; Little, Mark P.

    2015-01-01

    The theory of task-based assessment of image quality is reviewed in the context of imaging with ionizing radiation, and objective figures of merit (FOMs) for image quality are summarized. The variation of the FOMs with the task, the observer and especially with the mean number of photons recorded in the image is discussed. Then various standard methods for specifying radiation dose are reviewed and related to the mean number of photons in the image and hence to image quality. Current knowledge of the relation between local radiation dose and the risk of various adverse effects is summarized, and some graphical depictions of the tradeoffs between image quality and risk are introduced. Then various dose-reduction strategies are discussed in terms of their effect on task-based measures of image quality. PMID:25564960

  2. Task planning and action coordination in integrated sensor-based robots

    SciTech Connect

    Chen, C.; Trivedi, M.M.

    1995-04-01

    A System Architecture for Sensor-based Intelligent Robots (SASIR) is introduced. The system architecture consists of perception, motor, task planner, knowledge-base, user interface, and supervisor modules. SASIR is constructed using a frame data structure, which provides a suitable and flexible scheme for representation and manipulation of the world model, the sensor derived information, as well as for describing the actions required for the execution of a specific task. The experimental results show the basic validity of the general architecture as well as the robust and successful performance of two working systems: (1) the Autonomous Spill Cleaning (ASC) Robotic System, and (2) ROBOSIGHT, which is capable of a range of autonomous inspection and manipulation tasks. 45 refs.

  3. Knowledge-based load leveling and task allocation in human-machine systems

    NASA Technical Reports Server (NTRS)

    Chignell, M. H.; Hancock, P. A.

    1986-01-01

    Conventional human-machine systems use task allocation policies which are based on the premise of a flexible human operator. This individual is most often required to compensate for and augment the capabilities of the machine. The development of artificial intelligence and improved technologies have allowed for a wider range of task allocation strategies. In response to these issues a Knowledge Based Adaptive Mechanism (KBAM) is proposed for assigning tasks to human and machine in real time, using a load leveling policy. This mechanism employs an online workload assessment and compensation system which is responsive to variations in load through an intelligent interface. This interface consists of a loading strategy reasoner which has access to information about the current status of the human-machine system as well as a database of admissible human/machine loading strategies. Difficulties standing in the way of successful implementation of the load leveling strategy are examined.

  4. Adaptation of task difficulty in rehabilitation exercises based on the user's motor performance and physiological responses.

    PubMed

    Shirzad, Navid; Van der Loos, H F Machiel

    2013-06-01

    Although robot-assisted rehabilitation regimens are as effective, functionally, as conventional therapies, they still lack features to increase patients' engagement in the regimen. Providing rehabilitation tasks at a "desirable difficulty" is one of the ways to address this issue and increase the motivation of a patient to continue with the therapy program. Then the problem is to design a system that is capable of estimating the user's desirable difficulty, and ultimately, modifying the task based on this prediction. In this paper we compared the performance of three machine learning algorithms in predicting a user's desirable difficulty during a typical reaching motion rehabilitation task. Different levels of error amplification were used as different levels of task difficulty. We explored the usefulness of using participants' motor performance and physiological signals during the reaching task in prediction of their desirable difficulties. Results showed that a Neural Network approach gives higher prediction accuracy in comparison with models based on k-Nearest Neighbor and Discriminant Analysis methods.

  5. Reward-based training of recurrent neural networks for cognitive and value-based tasks

    PubMed Central

    Song, H Francis; Yang, Guangyu R; Wang, Xiao-Jing

    2017-01-01

    Trained neural network models, which exhibit features of neural activity recorded from behaving animals, may provide insights into the circuit mechanisms of cognitive functions through systematic analysis of network activity and connectivity. However, in contrast to the graded error signals commonly used to train networks through supervised learning, animals learn from reward feedback on definite actions through reinforcement learning. Reward maximization is particularly relevant when optimal behavior depends on an animal’s internal judgment of confidence or subjective preferences. Here, we implement reward-based training of recurrent neural networks in which a value network guides learning by using the activity of the decision network to predict future reward. We show that such models capture behavioral and electrophysiological findings from well-known experimental paradigms. Our work provides a unified framework for investigating diverse cognitive and value-based computations, and predicts a role for value representation that is essential for learning, but not executing, a task. DOI: http://dx.doi.org/10.7554/eLife.21492.001 PMID:28084991

  6. Nanotechnology-Based Electrochemical Sensors for Biomonitoring Chemical Exposures

    PubMed Central

    Barry, Richard C.; Lin, Yuehe; Wang, Jun; Liu, Guodong; Timchalk, Charles A.

    2009-01-01

    The coupling of dosimetry measurements and modeling represents a promising strategy for deciphering the relationship between chemical exposure and disease outcome. To support the development and implementation of biological monitoring programs, quantitative technologies for measuring xenobiotic exposure are needed. The development of portable nanotechnology-based electrochemical sensors has the potential to meet the needs for low cost, rapid, high-throughput and ultrasensitive detectors for biomonitoring an array of chemical markers. Highly selective electrochemical (EC) sensors capable of pM sensitivity, high-throughput and low sample requirements (<50uL) are discussed. These portable analytical systems have many advantages over currently available technologies, thus potentially representing the next-generation of biomonitoring analyzers. This manuscript highlights research focused on the development of field-deployable analytical instruments based on EC detection. Background information and a general overview of EC detection methods and integrated use of nanomaterials in the development of these sensors are provided. New developments in EC sensors using various types of screen-printed electrodes, integrated nanomaterials, and immunoassays are presented. Recent applications of EC sensors for assessing exposure to pesticides or detecting biomarkers of disease are highlighted to demonstrate the ability to monitor chemical metabolites, enzyme activity, or protein biomarkers of disease. In addition, future considerations and opportunities for advancing the use of EC platforms for dosimetric studies are discussed. PMID:19018275

  7. Exposure of baboons to combined 60 Hz electric and magnetic fields does not produce work stoppage or affect operant performance on a match-to-sample task

    SciTech Connect

    Orr, J.L.; Rogers, W.R.; Smith, H.D.

    1995-12-31

    The authors examined the effects of combined 60 Hz electric and magnetic field (EMF) exposure on performance of delayed match-to-sample (MTS) procedure involving the flash rate of a light as the stimulus. Six baboons (Papio cynocephalus) fully acquired the task; four others functioned accurately only when cued. All ten subjects were assigned to EMF-exposed or sham-exposed groups of five and were used to test for a work-stoppage effect that was previously observed with initial exposure to electric fields (EF) of 30 or 60 kV/m. Here, the authors report the results of two experiments, each consisting of 6 week preexposure, exposure, and postexposure periods. They found no evidence of work stoppage with fields of 6 kV/m and 50 {micro}T (0.5 G) or with 30 kV/m and 100 {micro}T (1.0 G). In neither experiment was there evidence of an adverse effect of 60 Hz EMF exposure on MTS performance.

  8. Task-based optimization of dedicated breast CT via Hotelling observer metrics

    PubMed Central

    Sanchez, Adrian A.; Sidky, Emil Y.; Pan, Xiaochuan

    2014-01-01

    Purpose: The purpose of this work is to develop and demonstrate a set of practical metrics for CT systems optimization. These metrics, based on the Hotelling observer (HO) figure of merit, are task-based. The authors therefore take the specific example of optimizing a dedicated breast CT system, including the reconstruction algorithm, for two relevant tasks, signal detection and Rayleigh discrimination. Methods: A dedicated breast CT system is simulated using specifications in the literature from an existing prototype. The authors optimize configuration and image reconstruction algorithm parameters for two tasks: the detection of simulated microcalcifications and the discrimination of two adjacent, high-contrast signals, known as the Rayleigh discrimination task. The effects on task performance of breast diameter, signal location, image grid size, projection view number, and reconstruction filter were all investigated. Two HO metrics were evaluated: the percentage of correct decisions in a two-alternative forced choice experiment (equivalent to area under the ROC curve or AUC), and the HO efficiency, defined as the squared ratio of HO signal-to-noise ratio (SNR) in the reconstructed image to HO SNR in the projection data. Results: The ease and efficiency of the HO metric computation allows a rapid high-resolution survey of many system parameters. Optimization of a range of system parameters using the HO results in images that subjectively appear optimal for the tasks investigated. Further, the results of assessment through the HO reproduce closely many existing results in the literature regarding the impact of parameter selection on image quality. Conclusions: This study demonstrates the utility of a task-based approach to system design, evaluation, and optimization. The methodology presented is equally applicable to determining the impact of a wide range of factors, including patient parameters, system and acquisition design, and the reconstruction algorithm. The

  9. Taking Teacher Education to Task: Exploring the Role of Teacher Education in Promoting the Utilization of Task-Based Language Teaching

    ERIC Educational Resources Information Center

    Ogilvie, Greg; Dunn, William

    2010-01-01

    Despite its theoretical appeal and research-based support, task-based language teaching (TBLT) continues to have a somewhat limited influence on actual second language teaching practices in many contexts. This study considers the relationship between teacher education and the broader use of TBLT. It investigates the effects of a…

  10. Teachers' Perceptions of Task-Based Language Teaching in English Classrooms in Taiwanese Junior High Schools

    ERIC Educational Resources Information Center

    Lin, Tzu-Bin; Wu, Chiao-Wen

    2012-01-01

    After introducing new curriculum guidelines during education reform, the Taiwan Ministry of Education has taken the lead in integrating a communicative approach into the new English language curriculum. Task-based language teaching (TBLT) is viewed as a realisation of communicative language teaching and is one of the most popular English language…

  11. Task-Based Language Teaching in Online Ab Initio Foreign Language Classrooms

    ERIC Educational Resources Information Center

    Lai, Chun; Zhao, Yong; Wang, Jiawen

    2011-01-01

    Task-based language teaching (TBLT) has been attracting the attention of researchers for more than 2 decades. Research on various aspects of TBLT has been accumulating, including the evaluation studies on the implementation of TBLT in classrooms. The evaluation studies on students' and teachers' reactions to TBLT in the online courses are starting…

  12. Situated Task-Based Language Teaching in Chinese Colleges: Teacher Education

    ERIC Educational Resources Information Center

    Liu, Yuying; Xiong, Tao

    2016-01-01

    This study investigated college EFL teachers' attitudes toward task-based language teaching (TBLT), regarding their familiarity with the idea of TBLT, their actual use of TBLT, and contextual factors that impede the implementation of TBLT in the higher education context in China. The study described here is a questionnaire survey with 26 valid…

  13. Defense Science Board Task Force on the Review of the Defense Nuclear Agency Technology Base Program

    DTIC Science & Technology

    1982-04-01

    LTNCusTA RIE1D DEFENSE SCIENCE BOARD TASK FORCE REPORT REVIEW OF THE DEFENSE NUCLEAR AGENCY TECHNOLGY BASE PROGRAM April 1982 Office of the Under Secretary...become a " sugar daddy" for service labs that are under funding pressure. Nonetheless, the fact remains that a necessary condition for the utilization of

  14. Implementation of Task-Based Language Teaching in Chinese as a Foreign Language: Benefits and Challenges

    ERIC Educational Resources Information Center

    Bao, Rui; Du, Xiangyun

    2015-01-01

    Task-based language teaching (TBLT) has been drawing increased attention from language teachers and researchers in the past decade. This paper focuses on the effects of TBLT on beginner learners of Chinese as a foreign language (CFL) in Denmark. Participatory observation and semi-structured interviews were carried out with 18 participants from two…

  15. Task-Based Learning and Teaching in China: Secondary School Teachers' Beliefs and Practices

    ERIC Educational Resources Information Center

    Zheng, Xinmin; Borg, Simon

    2014-01-01

    While much has been written about task-based language teaching (TBLT), research examining teachers' understandings of what TBLT means remains limited. This article explores the understandings of TBLT of three Chinese secondary school teachers of English and the implementation of TBLT in their lessons. Narrative accounts were constructed for each…

  16. Language Form, Task-Based Language Teaching, and the Classroom Context

    ERIC Educational Resources Information Center

    Batstone, Rob

    2012-01-01

    In this article, I examine some of the ideas about task-based language teaching (TBLT) which have emerged over the 17 years of the current editorship of ELTJ, focusing in particular on grammar and vocabulary, and enquiring to what degree these ideas take adequate account of classroom context. Over this period, TBLT scholars have built up a…

  17. Evaluating Gaze-Based Interface Tools to Facilitate Point-and-Select Tasks with Small Targets

    ERIC Educational Resources Information Center

    Skovsgaard, Henrik; Mateo, Julio C.; Hansen, John Paulin

    2011-01-01

    Gaze interaction affords hands-free control of computers. Pointing to and selecting small targets using gaze alone is difficult because of the limited accuracy of gaze pointing. This is the first experimental comparison of gaze-based interface tools for small-target (e.g. less than 12 x 12 pixels) point-and-select tasks. We conducted two…

  18. Investigating the Washback Effects of Task-Based Instruction on the Iranian EFL Learners' Vocabulary Learning

    ERIC Educational Resources Information Center

    Hamzeh, Alireza

    2016-01-01

    The current research was an attempt to explore the washback impact of task-based instruction (TBI) on EFL Iranian learners' vocabulary development. To this end, conducting an Oxford Placement Test (OPT), 30 out of 72 EFL Iranian learners studying in an English language institute, were randomly selected. Then, they were assigned to experimental (N…

  19. Design and Analysis in Task-Based Language Assessment. CSE Technical Report.

    ERIC Educational Resources Information Center

    Mislevy, Robert J.; Steinberg, Linda S.; Almond, Russell G.

    Task-based language assessment (TBLA) grows from the observation that mastering the grammar and lexicon of a language is not sufficient for using a language to achieve ends in social situations. In TBLA, language use is observed in settings that are more realistic and complex than in discrete skills assessment and that typically require the…

  20. ESL Students' Interaction in Second Life: Task-Based Synchronous Computer-Mediated Communication

    ERIC Educational Resources Information Center

    Jee, Min Jung

    2010-01-01

    The purpose of the present study was to explore ESL students' interactions in task-based synchronous computer-mediated communication (SCMC) in Second Life, a virtual environment by which users can interact through representational figures. I investigated Low-Intermediate and High-Intermediate ESL students' interaction patterns before, during, and…

  1. Web-Based Seamless Migration for Task-Oriented Mobile Distance Learning

    ERIC Educational Resources Information Center

    Zhang, Degan; Li, Yuan-chao; Zhang, Huaiyu; Zhang, Xinshang; Zeng, Guangping

    2006-01-01

    As a new kind of computing paradigm, pervasive computing will meet the requirements of human being that anybody maybe obtain services in anywhere and at anytime, task-oriented seamless migration is one of its applications. Apparently, the function of seamless mobility is suitable for mobile services, such as mobile Web-based learning. In this…

  2. The Impact of Task-Based Approach on Vocabulary Learning in ESP Courses

    ERIC Educational Resources Information Center

    Sarani, Abdullah; Sahebi, Leila Farzaneh

    2012-01-01

    This study investigates the teaching of vocabulary in ESP courses within the paradigm of task-based language teaching, concentrating on Persian literature students at Birjand University in Iran. Two homogenous groups of students who were taking their ESP courses participated in the study as a control and an experimental group. A teacher-made test…

  3. Multilingual and Multicultural Task-Based Learning Scenarios: A Pilot Study from the MAGICC Project

    ERIC Educational Resources Information Center

    Álvarez, Inma; Pérez-Cavana, María Luisa

    2015-01-01

    In this article we report on the results of a pilot study on the use of task-based multilingual and multicultural professional scenarios for higher education teachers and learners at BA and MA level. The scenarios reflect new learning outcomes and assessment criteria for the presently under-conceptualised domain of communication in multilingual…

  4. Efficacy of Task-Based Learning in a Chinese EFL Classroom: A Case Study

    ERIC Educational Resources Information Center

    Tang, Hersong; Chiou, Jer-Shiou; Jarsaillon, Oliver

    2015-01-01

    This study investigated how task-based learning (TBL) developed the verbal competence of Chinese learners of English as a foreign language (EFL) by employing qualitative and quantitative analyses. We compared the impromptu oral presentations on reading texts of 76 intermediate EFL learners given respectively in the beginning and the end of the…

  5. Cognitive Support for Learning Computer-Based Tasks Using Animated Demonstration

    ERIC Educational Resources Information Center

    Chen, Chun-Ying

    2016-01-01

    This study investigated the influence of cognitive support for learning computer-based tasks using animated demonstration (AD) on instructional efficiency. Cognitive support included (1) segmentation and learner control introducing interactive devices that allow content sequencing through a navigational menu, and content pacing through stop and…

  6. Samples of Students' Responses from the Grade 9 Science Performance-Based Assessment Tasks, June 1993.

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton. Student Evaluation Branch.

    The purpose of this document is to provide teachers, administrators, students, and parents with samples of students' performances that exemplify standards in relation to the 1993 Grade 9 Science Performance-Based Assessment Tasks for the province of Alberta, Canada. A sample of 698 randomly selected students from 31 schools did the…

  7. Where Is It? How Deaf Adolescents Complete Fact-Based Internet Search Tasks

    ERIC Educational Resources Information Center

    Smith, Chad E.

    2007-01-01

    An exploratory study was designed to describe Internet search behaviors of deaf adolescents who used Internet search engines to complete fact-based search tasks. The study examined search behaviors of deaf high school students such as query formation, query modification, Web site identification, and Web site selection. Consisting of two fact-based…

  8. Using Virtual Reality for Task-Based Exercises in Teaching Non-Traditional Students of German

    ERIC Educational Resources Information Center

    Libbon, Stephanie

    2004-01-01

    Using task-based exercises that required web searches and online activities, this course introduced non-traditional students to the sights and sounds of the German culture and language and simultaneously to computer technology. Through partner work that required negotiation of the net as well as of the language, these adult beginning German…

  9. Task-Based Language Teaching: Responses from Chinese Teachers of English

    ERIC Educational Resources Information Center

    Hu, Ran

    2013-01-01

    The Task-based Language Teaching (TBLT) method has been the proposed teaching method under the current national English curriculum since 2001. However, few studies have investigated in-service teachers' response to this proposed language teaching method. In this study, thirty public school English teachers were recruited in Beijing across school…

  10. Reflecting on the Japan-Chile Task-Based Telecollaboration Project for Beginner-Level Learners

    ERIC Educational Resources Information Center

    Dunne, B. Greg

    2014-01-01

    Using O'Dowd and Ritter's (2006) Inventory of Reasons for Failed Communication in Telecollaborative Projects as a barometer, this article details the considerations and procedures followed in a task-based, asynchronous email telecollaboration project between EFL (English as a Foreign Language) learners in Japan and Chile. In a climate where…

  11. Task-Based Oral Computer-Mediated Communication and L2 Vocabulary Acquisition

    ERIC Educational Resources Information Center

    Yanguas, Inigo

    2012-01-01

    The present study adds to the computer-mediated communication (CMC) literature by exploring oral learner-to-learner interaction using Skype, a free and widely used Internet software program. In particular, this task-based study has a two-fold goal. Firstly, it explores possible differences between two modes of oral CMC (audio and video) and…

  12. A Feasibility Study of Task-Based Teaching of College English Writing in Chinese EFL Context

    ERIC Educational Resources Information Center

    Cao, Linying

    2012-01-01

    In this study the author draws on Jane Willis' TBL framework and examines its effects on the improvement of EFL learners' writing competence when such a framework is applied to college writing classrooms in Chinese EFL settings, and thus tentatively explores the feasibility of the task-based approach to the teaching of EFL writing. Results of this…

  13. Learning New Grammatical Structures in Task-Based Language Learning: The Effects of Recasts and Prompts

    ERIC Educational Resources Information Center

    Van de Guchte, Marrit; Braaksma, Martine; Rijlaarsdam, Gert; Bimmel, Peter

    2015-01-01

    In the present study, we examine the effects of prompts and recasts on the acquisition of two new and different grammar structures in a task-based learning environment. Sixty-four 14-year-old 9th grade students (low intermediate) learning German as a foreign language were randomly assigned to three conditions: two experimental groups (one…

  14. Using Task Based Writing Instruction to Provide Differentiated Instruction for English Language Learners

    ERIC Educational Resources Information Center

    Bantis, Alexandros Merkouris

    2008-01-01

    The purpose of this study was to investigate the impact of task based writing instruction (TBwI) on English language acquisition and differentiated instruction for minority language students during the Independent Work Time instructional component of the Open Court Reading program. One teacher and 10 third grade students (8-9 years old)…

  15. Task-Based Learning and Content and Language Integrated Learning Materials Design: Process and Product

    ERIC Educational Resources Information Center

    Moore, Pat; Lorenzo, Francisco

    2015-01-01

    Content and language integrated learning (CLIL) represents an increasingly popular approach to bilingual education in Europe. In this article, we describe and discuss a project which, in response to teachers' pleas for materials, led to the production of a significant bank of task-based primary and secondary CLIL units for three L2s (English,…

  16. The Impact of "Role Play" on Fostering EFL Learners' Speaking Ability: A Task-Based Approach

    ERIC Educational Resources Information Center

    Aliakbari, Mohammad; Jamalvandi, Behroz

    2010-01-01

    Marking as one dramatic turnover in language teaching, task-based language teaching (TBLT) has proved itself beneficial and effective in bringing about real situations of language use to take place and in satisfying communicative needs of learners while the former methods were unable to meet actual demands of learners to communicate in the target…

  17. Pedagogical Values of Mobile-Assisted Task-Based Activities to Enhance Speaking Skill

    ERIC Educational Resources Information Center

    Mohammadi, Mojtaba; Safdari, Nastaran

    2015-01-01

    The purpose of the present study was to examine the impact of online mobile-assisted task-based activities on improving Iranian intermediate English as a Foreign Language (EFL) learners' speaking skills. To achieve the purpose of the study, 90 intermediate language learners were selected ranging between 13 to 16 years old and divided into three…

  18. Evaluating Integrated Task Based Activities and Computer Assisted Language Learning (CALL)

    ERIC Educational Resources Information Center

    Anwar, Khoirul; Husniah, Rohmy

    2016-01-01

    This study is to evaluate the implementation of Task Activities based on CALL which consist of observing, questioning, exploring, and communicating. The developed materials are nine chapters that had been implemented in two different classes of SMPN 1 Gresik and SMPM 4 Gresik in Indonesia. Of quesionnaires and interviews, the results indicate that…

  19. Phonological and Executive Working Memory in L2 Task-Based Speech Planning and Performance

    ERIC Educational Resources Information Center

    Wen, Zhisheng

    2016-01-01

    The present study sets out to explore the distinctive roles played by two working memory (WM) components in various aspects of L2 task-based speech planning and performance. A group of 40 post-intermediate proficiency level Chinese EFL learners took part in the empirical study. Following the tenets and basic principles of the…

  20. Negative Feedback and Positive Evidence in Task-Based Interaction: Differential Effects on L2 Development

    ERIC Educational Resources Information Center

    Iwashita, Noriko

    2003-01-01

    This study examines the role of task-based conversation in second language (L2) grammatical development, focusing on the short-term effects of both negative feedback and positive evidence on the acquisition of two Japanese structures. The data are drawn from 55 L2 learners of Japanese at a beginning level of proficiency in an Australian tertiary…

  1. Addressing the Intercultural via Task-Based Language Teaching: Possibility or Problem?

    ERIC Educational Resources Information Center

    East, Martin

    2012-01-01

    A frequent weakness of communicative approaches to foreign language teaching is a neglect of the intercultural dimension. Cultural knowledge is often treated as an addendum which focuses on learning facts about the target country. This article explores whether task-based language teaching (TBLT) can successfully address the intercultural…

  2. Discursive Leadership and Conceptual Fluency in Non-Native English Speakers' Online Task-Based Dialogues

    ERIC Educational Resources Information Center

    Boz, Umit

    2014-01-01

    Much research has examined how different patterns of social interaction shape language learners' interactional roles (e.g., collaborative, dominant, passive) in peer-to-peer conversations. However, little or no research has investigated the co-construction of such roles in multiparty, online task-based dialogues within the framework of discursive…

  3. Computer-Assisted Foreign Language Instruction: Task Based vs. Form Focused

    ERIC Educational Resources Information Center

    Arslanyilmaz, A.

    2013-01-01

    The purpose of this article is twofold: to describe a prototype for a computer-assisted task-based language instruction (CATBI) tool designed and developed for Turkish as a Foreign Language, and to report on the effectiveness of the CATBI tool. More specifically, this work discusses an experimental study that examined the role of teaching approach…

  4. Identifying and individuating cognitive systems: a task-based distributed cognition alternative to agent-based extended cognition.

    PubMed

    Davies, Jim; Michaelian, Kourken

    2016-08-01

    This article argues for a task-based approach to identifying and individuating cognitive systems. The agent-based extended cognition approach faces a problem of cognitive bloat and has difficulty accommodating both sub-individual cognitive systems ("scaling down") and some supra-individual cognitive systems ("scaling up"). The standard distributed cognition approach can accommodate a wider variety of supra-individual systems but likewise has difficulties with sub-individual systems and faces the problem of cognitive bloat. We develop a task-based variant of distributed cognition designed to scale up and down smoothly while providing a principled means of avoiding cognitive bloat. The advantages of the task-based approach are illustrated by means of two parallel case studies: re-representation in the human visual system and in a biomedical engineering laboratory.

  5. Personal exposure to JP-8 jet fuel vapors and exhaust at air force bases.

    PubMed Central

    Pleil, J D; Smith, L B; Zelnick, S D

    2000-01-01

    JP-8 jet fuel (similar to commercial/international jet A-1 fuel) is the standard military fuel for all types of vehicles, including the U.S. Air Force aircraft inventory. As such, JP-8 presents the most common chemical exposure in the Air Force, particularly for flight and ground crew personnel during preflight operations and for maintenance personnel performing routine tasks. Personal exposure at an Air Force base occurs through occupational exposure for personnel involved with fuel and aircraft handling and/or through incidental exposure, primarily through inhalation of ambient fuel vapors. Because JP-8 is less volatile than its predecessor fuel (JP-4), contact with liquid fuel on skin and clothing may result in prolonged exposure. The slowly evaporating JP-8 fuel tends to linger on exposed personnel during their interaction with their previously unexposed colleagues. To begin to assess the relative exposures, we made ambient air measurements and used recently developed methods for collecting exhaled breath in special containers. We then analyzed for certain volatile marker compounds for JP-8, as well as for some aromatic hydrocarbons (especially benzene) that are related to long-term health risks. Ambient samples were collected by using compact, battery-operated, personal whole-air samplers that have recently been developed as commercial products; breath samples were collected using our single-breath canister method that uses 1-L canisters fitted with valves and small disposable breathing tubes. We collected breath samples from various groups of Air Force personnel and found a demonstrable JP-8 exposure for all subjects, ranging from slight elevations as compared to a control cohort to > 100 [mutilpe] the control values. This work suggests that further studies should be performed on specific issues to obtain pertinent exposure data. The data can be applied to assessments of health outcomes and to recommendations for changes in the use of personal protective

  6. Analysing task design and students' responses to context-based problems through different analytical frameworks

    NASA Astrophysics Data System (ADS)

    Broman, Karolina; Bernholt, Sascha; Parchmann, Ilka

    2015-05-01

    Background:Context-based learning approaches are used to enhance students' interest in, and knowledge about, science. According to different empirical studies, students' interest is improved by applying these more non-conventional approaches, while effects on learning outcomes are less coherent. Hence, further insights are needed into the structure of context-based problems in comparison to traditional problems, and into students' problem-solving strategies. Therefore, a suitable framework is necessary, both for the analysis of tasks and strategies. Purpose:The aim of this paper is to explore traditional and context-based tasks as well as students' responses to exemplary tasks to identify a suitable framework for future design and analyses of context-based problems. The paper discusses different established frameworks and applies the Higher-Order Cognitive Skills/Lower-Order Cognitive Skills (HOCS/LOCS) taxonomy and the Model of Hierarchical Complexity in Chemistry (MHC-C) to analyse traditional tasks and students' responses. Sample:Upper secondary students (n=236) at the Natural Science Programme, i.e. possible future scientists, are investigated to explore learning outcomes when they solve chemistry tasks, both more conventional as well as context-based chemistry problems. Design and methods:A typical chemistry examination test has been analysed, first the test items in themselves (n=36), and thereafter 236 students' responses to one representative context-based problem. Content analysis using HOCS/LOCS and MHC-C frameworks has been applied to analyse both quantitative and qualitative data, allowing us to describe different problem-solving strategies. Results:The empirical results show that both frameworks are suitable to identify students' strategies, mainly focusing on recall of memorized facts when solving chemistry test items. Almost all test items were also assessing lower order thinking. The combination of frameworks with the chemistry syllabus has been

  7. Acute Exposure to Stress Improves Performance in Trace Eyeblink Conditioning and Spatial Learning Tasks in Healthy Men

    ERIC Educational Resources Information Center

    Duncko, Roman; Cornwell, Brian; Cui, Lihong; Merikangas, Kathleen R.; Grillon, Christian

    2007-01-01

    The present study investigated the effects of acute stress exposure on learning performance in humans using analogs of two paradigms frequently used in animals. Healthy male participants were exposed to the cold pressor test (CPT) procedure, i.e., insertion of the dominant hand into ice water for 60 sec. Following the CPT or the control procedure,…

  8. Effects of cycloheximide on extinction in an appetitively motivated operant conditioning task depend on re-exposure duration.

    PubMed

    Mierzejewski, Pawel; Olczak, Mieszko; Rogowski, Artur; Kostowski, Wojciech; Samochowiec, Jerzy; Filip, Malgorzata; Przegalinski, Edmund; Bienkowski, Przemyslaw

    2008-08-29

    Little is known about the role of new protein synthesis in extinction of operant responding for natural and chemical reinforcers. In the present study, the authors investigated whether the effects of a protein synthesis inhibitor, cycloheximide (CHX) on extinction of operant responding for sweet reward depended on the duration of re-exposure sessions. In addition, the authors investigated whether the effects of CHX on extinction could generalize to relapse of saccharin seeking induced by discrete cues. CHX injected after short re-exposure sessions (5min) accelerated extinction of non-reinforced responding. In contrast, the drug injected after long re-exposure sessions (30min) partially inhibited extinction. Reinstatement of saccharin seeking induced by the saccharin-paired discrete cues was not altered by the previous treatment with CHX. Concluding, the results of the present study indicate that: (i) the protein synthesis inhibitor, CHX can alter extinction of operant responding for sweet reward in rats; (ii) the effects of CHX on extinction critically depend on the duration of re-exposure/extinction sessions and do not generalize to relapse of saccharin seeking induced by discrete cues.

  9. Moving from Virtual Reality Exposure-Based Therapy to Augmented Reality Exposure-Based Therapy: A Review

    PubMed Central

    Baus, Oliver; Bouchard, Stéphane

    2014-01-01

    This paper reviews the move from virtual reality exposure-based therapy to augmented reality exposure-based therapy (ARET). Unlike virtual reality (VR), which entails a complete virtual environment (VE), augmented reality (AR) limits itself to producing certain virtual elements to then merge them into the view of the physical world. Although, the general public may only have become aware of AR in the last few years, AR type applications have been around since beginning of the twentieth century. Since, then, technological developments have enabled an ever increasing level of seamless integration of virtual and physical elements into one view. Like VR, AR allows the exposure to stimuli which, due to various reasons, may not be suitable for real-life scenarios. As such, AR has proven itself to be a medium through which individuals suffering from specific phobia can be exposed “safely” to the object(s) of their fear, without the costs associated with programing complete VEs. Thus, ARET can offer an efficacious alternative to some less advantageous exposure-based therapies. Above and beyond presenting what has been accomplished in ARET, this paper covers some less well-known aspects of the history of AR, raises some ARET related issues, and proposes potential avenues to be followed. These include the type of measures to be used to qualify the user’s experience in an augmented reality environment, the exclusion of certain AR-type functionalities from the definition of AR, as well as the potential use of ARET to treat non-small animal phobias, such as social phobia. PMID:24624073

  10. Moving from virtual reality exposure-based therapy to augmented reality exposure-based therapy: a review.

    PubMed

    Baus, Oliver; Bouchard, Stéphane

    2014-01-01

    This paper reviews the move from virtual reality exposure-based therapy to augmented reality exposure-based therapy (ARET). Unlike virtual reality (VR), which entails a complete virtual environment (VE), augmented reality (AR) limits itself to producing certain virtual elements to then merge them into the view of the physical world. Although, the general public may only have become aware of AR in the last few years, AR type applications have been around since beginning of the twentieth century. Since, then, technological developments have enabled an ever increasing level of seamless integration of virtual and physical elements into one view. Like VR, AR allows the exposure to stimuli which, due to various reasons, may not be suitable for real-life scenarios. As such, AR has proven itself to be a medium through which individuals suffering from specific phobia can be exposed "safely" to the object(s) of their fear, without the costs associated with programing complete VEs. Thus, ARET can offer an efficacious alternative to some less advantageous exposure-based therapies. Above and beyond presenting what has been accomplished in ARET, this paper covers some less well-known aspects of the history of AR, raises some ARET related issues, and proposes potential avenues to be followed. These include the type of measures to be used to qualify the user's experience in an augmented reality environment, the exclusion of certain AR-type functionalities from the definition of AR, as well as the potential use of ARET to treat non-small animal phobias, such as social phobia.

  11. Behavior-Based Multi-Robot Collaboration for Autonomous Construction Tasks

    NASA Technical Reports Server (NTRS)

    Stroupe, Ashley; Huntsberger, Terry; Okon, Avi; Aghazarian, Hrand; Robinson, Matthew

    2005-01-01

    We present a heterogeneous multi-robot system for autonomous construction of a structure through assembly of long components. Placement of a component within an existing structure in a realistic environment is demonstrated on a two-robot team. The task requires component acquisition, cooperative transport, and cooperative precision manipulation. Far adaptability, the system is designed as a behavior-based architecture. Far applicability to space-related construction efforts, computation, power, communication, and sensing are minimized, though the techniques developed are also applicable to terrestrial construction tasks.

  12. Improving multitasking assessment in healthy older adults using a prop-based version of the Breakfast task.

    PubMed

    Kosowicz, Maria; MacPherson, Sarah E

    2017-01-01

    Computerized cognitive assessment is becoming increasingly more common in clinical neuropsychological assessment and cognitive neuropsychological research. A number of computerized tasks now exist to assess multitasking abilities that are essential for everyday tasks such as cooking, shopping, or driving, but little is known about whether these tasks are appropriate for assessing older adults' multitasking. The present study directly compared age effects on multitasking when assessed using a computerized and a prop-based version of Craik and Bialystok's ( 2006 ) Breakfast task. Twenty participants aged 18 to 24 years and 20 participants aged 60 to 79 years were assessed on both versions of the Breakfast task. While age-related decrements in multitasking performance were found using the computerized task, significant age differences were not found on the majority of measures when the prop-based version was administered. The results suggest that age-related deficits in multitasking will be less when more contextualized, noncomputer based tasks are used.

  13. Task-based weights for photon counting spectral x-ray imaging

    SciTech Connect

    Bornefalk, Hans

    2011-11-15

    Purpose: To develop a framework for taking the spatial frequency composition of an imaging task into account when determining optimal bin weight factors for photon counting energy sensitive x-ray systems. A second purpose of the investigation is to evaluate the possible improvement compared to using pixel based weights. Methods: The Fourier based approach of imaging performance and detectability index d' is applied to pulse height discriminating photon counting systems. The dependency of d' on the bin weight factors is made explicit, taking into account both differences in signal and noise transfer characteristics across bins and the spatial frequency dependency of interbin correlations from reabsorbed scatter. Using a simplified model of a specific silicon detector, d' values for a high and a low frequency imaging task are determined for optimal weights and compared to pixel based weights. Results: The method successfully identifies bins where a large point spread function degrades detection of high spatial frequency targets. The method is also successful in determining how to downweigh highly correlated bins. Quantitative predictions for the simplified silicon detector model indicate that improvements in the detectability index when applying task-based weights instead of pixel based weights are small for high frequency targets, but could be in excess of 10% for low frequency tasks where scatter-induced correlation otherwise degrade detectability. Conclusions: The proposed method makes the spatial frequency dependency of complex correlation structures between bins and their effect on the system detective quantum efficiency easier to analyze and allows optimizing bin weights for given imaging tasks. A potential increase in detectability of double digit percents in silicon detector systems operated at typical CT energies (100 kVp) merits further evaluation on a real system. The method is noted to be of higher relevance for silicon detectors than for cadmium (zink

  14. Resting-State and Task-Based Functional Brain Connectivity in Developmental Dyslexia

    PubMed Central

    Schurz, Matthias; Wimmer, Heinz; Richlan, Fabio; Ludersdorfer, Philipp; Klackl, Johannes; Kronbichler, Martin

    2015-01-01

    Reading requires the interaction between multiple cognitive processes situated in distant brain areas. This makes the study of functional brain connectivity highly relevant for understanding developmental dyslexia. We used seed-voxel correlation mapping to analyse connectivity in a left-hemispheric network for task-based and resting-state fMRI data. Our main finding was reduced connectivity in dyslexic readers between left posterior temporal areas (fusiform, inferior temporal, middle temporal, superior temporal) and the left inferior frontal gyrus. Reduced connectivity in these networks was consistently present for 2 reading-related tasks and for the resting state, showing a permanent disruption which is also present in the absence of explicit task demands and potential group differences in performance. Furthermore, we found that connectivity between multiple reading-related areas and areas of the default mode network, in particular the precuneus, was stronger in dyslexic compared with nonimpaired readers. PMID:25169986

  15. Forecasting exposure to volcanic ash based on ash dispersion modeling

    NASA Astrophysics Data System (ADS)

    Peterson, Rorik A.; Dean, Ken G.

    2008-03-01

    A technique has been developed that uses Puff, a volcanic ash transport and dispersion (VATD) model, to forecast the relative exposure of aircraft and ground facilities to ash from a volcanic eruption. VATD models couple numerical weather prediction (NWP) data with physical descriptions of the initial eruptive plume, atmospheric dispersion, and settling of ash particles. Three distinct examples of variations on the technique are given using ERA-40 archived reanalysis NWP data. The Feb. 2000 NASA DC-8 event involving an eruption of Hekla volcano, Iceland is first used for analyzing a single flight. Results corroborate previous analyses that conclude the aircraft did encounter a diffuse cloud of volcanic origin, and indicate exposure within a factor of 10 compared to measurements made on the flight. The sensitivity of the technique to dispersion physics is demonstrated. The Feb. 2001 eruption of Mt. Cleveland, Alaska is used as a second example to demonstrate how this technique can be utilized to quickly assess the potential exposure of a multitude of aircraft during and soon after an event. Using flight tracking data from over 40,000 routes over three days, several flights that may have encountered low concentrations of ash were identified, and the exposure calculated. Relative changes in the quantity of exposure when the eruption duration is varied are discussed, and no clear trend is evident as the exposure increased for some flights and decreased for others. A third application of this technique is demonstrated by forecasting the near-surface airborne concentrations of ash that the cities of Yakima Washington, Boise Idaho, and Kelowna British Columbia might have experienced from an eruption of Mt. St. Helens anytime during the year 2000. Results indicate that proximity to the source does not accurately determine the potential hazard. Although an eruption did not occur during this time, the results serve as a demonstration of how existing cities or potential

  16. Professional Task-Based Curriculum Development for Distance Education Practitioners at Master's Level: A Design-Based Research

    ERIC Educational Resources Information Center

    Feng, Xiaoying; Lu, Guangxin; Yao, Zhihong

    2015-01-01

    Curriculum development for distance education (DE) practitioners is more and more focusing on practical requirements and competence development. Delphi and DACUM methods have been used at some universities. However, in the competency-based development area, these methods have been taken over by professional-task-based development in the last…

  17. TBDQ: A Pragmatic Task-Based Method to Data Quality Assessment and Improvement

    PubMed Central

    Vaziri, Reza; Mohsenzadeh, Mehran; Habibi, Jafar

    2016-01-01

    Organizations are increasingly accepting data quality (DQ) as a major key to their success. In order to assess and improve DQ, methods have been devised. Many of these methods attempt to raise DQ by directly manipulating low quality data. Such methods operate reactively and are suitable for organizations with highly developed integrated systems. However, there is a lack of a proactive DQ method for businesses with weak IT infrastructure where data quality is largely affected by tasks that are performed by human agents. This study aims to develop and evaluate a new method for structured data, which is simple and practical so that it can easily be applied to real world situations. The new method detects the potentially risky tasks within a process, and adds new improving tasks to counter them. To achieve continuous improvement, an award system is also developed to help with the better selection of the proposed improving tasks. The task-based DQ method (TBDQ) is most appropriate for small and medium organizations, and simplicity in implementation is one of its most prominent features. TBDQ is case studied in an international trade company. The case study shows that TBDQ is effective in selecting optimal activities for DQ improvement in terms of cost and improvement. PMID:27192547

  18. Task Allocation of Wasps Governed by Common Stomach: A Model Based on Electric Circuits

    PubMed Central

    2016-01-01

    Simple regulatory mechanisms based on the idea of the saturable ‘common stomach’ can control the regulation of construction behavior and colony-level responses to environmental perturbations in Metapolybia wasp societies. We mapped the different task groups to mutual inductance electrical circuits and used Kirchoff’s basic voltage laws to build a model that uses master equations from physics, yet is able to provide strong predictions for this complex biological phenomenon. Similar to real colonies, independently of the initial conditions, the system shortly sets into an equilibrium, which provides optimal task allocation for a steady construction, depending on the influx of accessible water. The system is very flexible and in the case of perturbations, it reallocates its workforce and adapts to the new situation with different equilibrium levels. Similar to the finding of field studies, decreasing any task groups caused decrease of construction; increasing or decreasing water inflow stimulated or reduced the work of other task groups while triggering compensatory behavior in water foragers. We also showed that only well connected circuits are able to produce adequate construction and this agrees with the finding that this type of task partitioning only exists in larger colonies. Studying the buffer properties of the common stomach and its effect on the foragers revealed that it provides stronger negative feedback to the water foragers, while the connection between the pulp foragers and the common stomach has a strong fixed-point attractor, as evidenced by the dissipative trajectory. PMID:27861633

  19. Task Allocation of Wasps Governed by Common Stomach: A Model Based on Electric Circuits.

    PubMed

    Hilbun, Allison; Karsai, Istvan

    2016-01-01

    Simple regulatory mechanisms based on the idea of the saturable 'common stomach' can control the regulation of construction behavior and colony-level responses to environmental perturbations in Metapolybia wasp societies. We mapped the different task groups to mutual inductance electrical circuits and used Kirchoff's basic voltage laws to build a model that uses master equations from physics, yet is able to provide strong predictions for this complex biological phenomenon. Similar to real colonies, independently of the initial conditions, the system shortly sets into an equilibrium, which provides optimal task allocation for a steady construction, depending on the influx of accessible water. The system is very flexible and in the case of perturbations, it reallocates its workforce and adapts to the new situation with different equilibrium levels. Similar to the finding of field studies, decreasing any task groups caused decrease of construction; increasing or decreasing water inflow stimulated or reduced the work of other task groups while triggering compensatory behavior in water foragers. We also showed that only well connected circuits are able to produce adequate construction and this agrees with the finding that this type of task partitioning only exists in larger colonies. Studying the buffer properties of the common stomach and its effect on the foragers revealed that it provides stronger negative feedback to the water foragers, while the connection between the pulp foragers and the common stomach has a strong fixed-point attractor, as evidenced by the dissipative trajectory.

  20. Work-In-Progress Peer Consult on EPA's Multimedia Exposure Analysis to Inform a Public Health-Based Value for Lead in Drinking Water

    EPA Science Inventory

    This document is a compilation of responses from four external peer reviewers on EPA's "Multimedia Exposure Analysis to Inform a Public Health-Based Value for Lead in Drinking Water." It was delivered by Versar, Inc. under contract number EP-C-12-045 Task Order 91.

  1. Attentional Demand of a Virtual Reality-Based Reaching Task in Nondisabled Older Adults

    PubMed Central

    Chen, Yi-An; Chung, Yu-Chen; Proffitt, Rachel; Wade, Eric; Winstein, Carolee

    2015-01-01

    Attention during exercise is known to affect performance; however, the attentional demand inherent to virtual reality (VR)-based exercise is not well understood. We used a dual-task paradigm to compare the attentional demands of VR-based and non-VR-based (conventional, real-world) exercise: 22 non-disabled older adults performed a primary reaching task to virtual and real targets in a counterbalanced block order while verbally responding to an unanticipated auditory tone in one third of the trials. The attentional demand of the primary reaching task was inferred from the voice response time (VRT) to the auditory tone. Participants' engagement level and task experience were also obtained using questionnaires. The virtual target condition was more attention demanding (significantly longer VRT) than the real target condition. Secondary analyses revealed a significant interaction between engagement level and target condition on attentional demand. For participants who were highly engaged, attentional demand was high and independent of target condition. However, for those who were less engaged, attentional demand was low and depended on target condition (i.e., virtual > real). These findings add important knowledge to the growing body of research pertaining to the development and application of technology-enhanced exercise for elders and for rehabilitation purposes. PMID:27004233

  2. Attentional Demand of a Virtual Reality-Based Reaching Task in Nondisabled Older Adults.

    PubMed

    Chen, Yi-An; Chung, Yu-Chen; Proffitt, Rachel; Wade, Eric; Winstein, Carolee

    2015-12-01

    Attention during exercise is known to affect performance; however, the attentional demand inherent to virtual reality (VR)-based exercise is not well understood. We used a dual-task paradigm to compare the attentional demands of VR-based and non-VR-based (conventional, real-world) exercise: 22 non-disabled older adults performed a primary reaching task to virtual and real targets in a counterbalanced block order while verbally responding to an unanticipated auditory tone in one third of the trials. The attentional demand of the primary reaching task was inferred from the voice response time (VRT) to the auditory tone. Participants' engagement level and task experience were also obtained using questionnaires. The virtual target condition was more attention demanding (significantly longer VRT) than the real target condition. Secondary analyses revealed a significant interaction between engagement level and target condition on attentional demand. For participants who were highly engaged, attentional demand was high and independent of target condition. However, for those who were less engaged, attentional demand was low and depended on target condition (i.e., virtual > real). These findings add important knowledge to the growing body of research pertaining to the development and application of technology-enhanced exercise for elders and for rehabilitation purposes.

  3. Task-based evaluation of practical lens designs for lens-coupled digital mammography systems

    NASA Astrophysics Data System (ADS)

    Chen, Liying; Foo, Leslie D.; Cortesi, Rebecca L.; Thompson, Kevin P.; Barrett, Harrison H.

    2007-03-01

    Recent developments in low-noise, large-area CCD detectors have renewed interest in radiographic systems that use a lens to couple light from a scintillation screen to a detector. The lenses for this application must have very large numerical apertures and high spatial resolution over a FOV. This paper expands on our earlier work by applying the principles of task-based assessment of image quality to development of meaningful figures of merit for the lenses. The task considered in this study is detection of a lesion in a mammogram, and the figure of merit used is the lesion detectability, expressed as a task-based signal-to-noise ratio (SNR), for a channelized Hotelling observer (CHO). As in the previous work, the statistical model accounts for the random structure in the breast, the statistical properties of the scintillation screen, the random coupling of light to the CCD, the detailed structure of the shift-variant lens point spread function (PSF), and Poisson noise of the X-ray flux. The lenses considered range from F/0.9 to F/1.2. All yield nominally the same spot size at a given field. Among the F/0.9 lenses, some of them were designed by conventional means for high resolution and some for high contrast, and the shapes of the PSF differ considerably. The results show that excessively large lens numerical apertures do not improve the task-based SNR but dramatically increase the optics fabrication cost. Contrary to common wisdom, high-contrast designs have higher task-based SNRs than high-resolution designs when the signal is small. Additionally, we constructed a merit function to successfully tune the lenses to perform equally well anywhere in the FOV.

  4. Relating UMLS semantic types and task-based ontology to computer-interpretable clinical practice guidelines.

    PubMed

    Kumar, Anand; Ciccarese, Paolo; Quaglini, Silvana; Stefanelli, Mario; Caffi, Ezio; Boiocchi, Lorenzo

    2003-01-01

    Medical knowledge in clinical practice guideline (GL) texts is the source of task-based computer-interpretable clinical guideline models (CIGMs). We have used Unified Medical Language System (UMLS) semantic types (STs) to understand the percentage of GL text which belongs to a particular ST. We also use UMLS semantic network together with the CIGM-specific ontology to derive a semantic meaning behind the GL text. In order to achieve this objective, we took nine GL texts from the National Guideline Clearinghouse (NGC) and marked up the text dealing with a particular ST. The STs we took into consideration were restricted taking into account the requirements of a task-based CIGM. We used DARPA Agent Markup Language and Ontology Inference Layer (DAML + OIL) to create the UMLS and CIGM specific semantic network. For the latter, as a bench test, we used the 1999 WHO-International Society of Hypertension Guidelines for the Management of Hypertension. We took into consideration the UMLS STs closest to the clinical tasks. The percentage of the GL text dealing with the ST "Health Care Activity" and subtypes "Laboratory Procedure", "Diagnostic Procedure" and "Therapeutic or Preventive Procedure" were measured. The parts of text belonging to other STs or comments were separated. A mapping of terms belonging to other STs was done to the STs under "HCA" for representation in DAML + OIL. As a result, we found that the three STs under "HCA" were the predominant STs present in the GL text. In cases where the terms of related STs existed, they were mapped into one of the three STs. The DAML + OIL representation was able to describe the hierarchy in task-based CIGMs. To conclude, we understood that the three STs could be used to represent the semantic network of the task-bases CIGMs. We identified some mapping operators which could be used for the mapping of other STs into these.

  5. Nanotechnology-Based Electrochemical Sensors for Biomonitoring Chemical Exposures

    SciTech Connect

    Barry, Richard C.; Lin, Yuehe; Wang, Jun; Liu, Guodong; Timchalk, Charles

    2009-01-01

    This manuscript highlights research focused on the development of field-deployable analytical instruments based on EC detection. Background information and a general overview of EC detection methods and integrated use of nanomaterials in the development of these sensors are provided. New developments in EC sensors using various types of screen-printed electrodes, integrated nanomaterials, and immunoassays are discussed. Recent applications of EC sensors for assessing exposure to pesticides or detecting biomarkers of disease are highlighted to demonstrate the ability to monitor chemical metabolites, enzyme activity, or protein biomarkers of disease. In addition, future considerations and opportunities for advancing the use of EC platforms for dosimetric studies are covered.

  6. Evaluation of noise pollution level based upon community exposure and response data

    NASA Technical Reports Server (NTRS)

    Edmiston, R. D.

    1972-01-01

    The results and procedures are reported from an evaluation of noise pollution level as a predictor of annoyance, based on aircraft noise exposure and community response data. The measures of noise exposure presented include composite noise rating, noise exposure forecast, noise and number index. A proposed measure as a universal noise exposure measure for noise pollution level (L sub NP) is discussed.

  7. A latent discriminative model-based approach for classification of imaginary motor tasks from EEG data

    NASA Astrophysics Data System (ADS)

    Delgado Saa, Jaime F.; Çetin, Müjdat

    2012-04-01

    We consider the problem of classification of imaginary motor tasks from electroencephalography (EEG) data for brain-computer interfaces (BCIs) and propose a new approach based on hidden conditional random fields (HCRFs). HCRFs are discriminative graphical models that are attractive for this problem because they (1) exploit the temporal structure of EEG; (2) include latent variables that can be used to model different brain states in the signal; and (3) involve learned statistical models matched to the classification task, avoiding some of the limitations of generative models. Our approach involves spatial filtering of the EEG signals and estimation of power spectra based on autoregressive modeling of temporal segments of the EEG signals. Given this time-frequency representation, we select certain frequency bands that are known to be associated with execution of motor tasks. These selected features constitute the data that are fed to the HCRF, parameters of which are learned from training data. Inference algorithms on the HCRFs are used for the classification of motor tasks. We experimentally compare this approach to the best performing methods in BCI competition IV as well as a number of more recent methods and observe that our proposed method yields better classification accuracy.

  8. Comparing features extractors in EEG-based cognitive fatigue detection of demanding computer tasks.

    PubMed

    Rifai Chai; Smith, Mitchell R; Nguyen, Tuan N; Sai Ho Ling; Coutts, Aaron J; Nguyen, Hung T

    2015-01-01

    An electroencephalography (EEG)-based classification system could be used as a tool for detecting cognitive fatigue from demanding computer tasks. The most widely used feature extractor in EEG-based fatigue classification is power spectral density (PSD). This paper investigates PSD and three alternative feature extraction methods, in order to find the best feature extractor for the classification of cognitive fatigue during cognitively demanding tasks. These compared methods are power spectral entropy (PSE), wavelet, and autoregressive (AR). Bayesian neural network was selected as the classifier in this study. The results showed that the use of PSD and PSE methods provide an average accuracy of 60% for each computer task. This finding is slightly improved using the wavelet method which has an average accuracy of 61%. The AR method is the best feature extractor compared with the PSD, PSE and wavelet in this study with accuracy of 75.95% in AX-continuous performance test (AX-CPT), 75.23% in psychomotor vigilance test (PVT) and 76.02% in Stroop task (p-value <; 0.05).

  9. Production Task Queue Optimization Based on Multi-Attribute Evaluation for Complex Product Assembly Workshop

    PubMed Central

    Li, Lian-hui; Mo, Rong

    2015-01-01

    The production task queue has a great significance for manufacturing resource allocation and scheduling decision. Man-made qualitative queue optimization method has a poor effect and makes the application difficult. A production task queue optimization method is proposed based on multi-attribute evaluation. According to the task attributes, the hierarchical multi-attribute model is established and the indicator quantization methods are given. To calculate the objective indicator weight, criteria importance through intercriteria correlation (CRITIC) is selected from three usual methods. To calculate the subjective indicator weight, BP neural network is used to determine the judge importance degree, and then the trapezoid fuzzy scale-rough AHP considering the judge importance degree is put forward. The balanced weight, which integrates the objective weight and the subjective weight, is calculated base on multi-weight contribution balance model. The technique for order preference by similarity to an ideal solution (TOPSIS) improved by replacing Euclidean distance with relative entropy distance is used to sequence the tasks and optimize the queue by the weighted indicator value. A case study is given to illustrate its correctness and feasibility. PMID:26414758

  10. A situated reasoning architecture for space-based repair and replace tasks

    NASA Technical Reports Server (NTRS)

    Bloom, Ben; Mcgrath, Debra; Sanborn, Jim

    1989-01-01

    Space-based robots need low level control for collision detection and avoidance, short-term load management, fine-grained motion, and other physical tasks. In addition, higher level control is required to focus strategic decision making as missions are assigned and carried out. Reasoning and control must be responsive to ongoing changes in the environment. Research aimed at bridging the gap between high level artificial intelligence (AI) planning techniques and task-level robot programming for telerobotic systems is described. Situated reasoning is incorporated into AI and Robotics systems in order to coordinate a robot's activity within its environment. An integrated system under development in a component maintenance domain is described. It is geared towards replacing worn and/or failed Orbital Replacement Units (ORUs) designed for use aboard NASA's Space Station Freedom based on the collection of components available at a given time. High level control reasons in component space in order to maximize the number operational component-cells over time, while the task-level controls sensors and effectors, detects collisions, and carries out pick and place tasks in physical space. Situated reasoning is used throughout the system to cope with component failures, imperfect information, and unexpected events.

  11. Space transportation nodes assumptions and requirements: Lunar base systems study task 2.1

    NASA Technical Reports Server (NTRS)

    Kahn, Taher Ali; Simonds, Charles H.; Stump, William R.

    1988-01-01

    The Space Transportation Nodes Assumptions and Requirements task was performed as part of the Advanced Space Transportation Support Contract, a NASA Johnson Space Center (JSC) study intended to provide planning for a Lunar Base near the year 2000. The original task statement has been revised to satisfy the following queries: (1) What vehicles are to be processed at the transportation node; (2) What is the flow of activities involved in a vehicle passing through the node; and (3) What node support resources are necessary to support a lunar scenario traffic model composed of a mix of vehicles in an active flight schedule. The Lunar Base Systems Study is concentrating on the initial years of the Phase 2 Lunar Base Scenario. The study will develop the first five years of that phase in order to define the transportation and surface systems (including mass, volumes, power requirements, and designs).

  12. Exposure-response relationships between occupational exposures and chronic respiratory illness: a community-based study.

    PubMed

    Xu, X; Christiani, D C; Dockery, D W; Wang, L

    1992-08-01

    Data from a random sample of 3,606 adults 40 to 69 yr of age residing in Beijing, China, were analyzed to investigate the association of reported occupational exposures to dusts and gases/fumes with the prevalence of chronic respiratory symptoms and level of pulmonary function. The prevalence of occupational dust exposure was 32%, and gas or fume exposure, 19%. After we adjusted for age, sex, area of residence, smoking status, coal stove heating, and education, an increased prevalence of chronic phlegm and breathlessness was significantly related to both types of exposures. Chronic cough was significantly related only to dust exposure, and persistent wheeze only to fume exposure. The global estimates of the relative odds of the four symptoms were 1.30 (95% CI [confidence interval] 1.09 to 1.48) and 1.27 (95% CI 1.09 to 1.48), respectively, for dusts and for gases/fumes. These two occupational exposures are associated with chronic respiratory symptoms independent of smoking, gender, and each other. There was an increasing prevalence of each symptom with increasing dust and fume exposure, represented by the index of cumulative exposure duration and exposure intensity. Linear trends for increased prevalence of chronic bronchitis and breathlessness were significant for both exposures, while the linear trend for wheeze was only significant for gases/fumes. Among subjects who did not report using coal stove heating, dust exposure was a significant predictor for FEV1, FEV1/FVC, FEF25-75, and peak expiratory flow rate (PEFR). There was also a significant decrease for FEV1 and FVC with increase of gas/fume exposure levels. Both current and former smokers appeared to be more susceptible to the effect of dusts than the never smokers.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Setting evidence-based occupational exposure limits for manganese.

    PubMed

    Bevan, Ruth; Ashdown, Lini; McGough, Doreen; Huici-Montagud, Alicia; Levy, Leonard

    2017-01-01

    In 2004, a review by the Institute of Environment and Health (IEH) made recommendations on occupational exposure limits (OELs) for manganese and its inorganic compounds for inhalable and respirable fractions respectively. These OELs were based on a detailed comprehensive evaluation of all the scientific data available at that time. Since then, more published studies have become available and a number of occupational standard-setting committees (EU SCOEL, US ACGIH-TLV, and German MAK) have proposed OEL's for manganese and its inorganic compounds that are somewhat lower that those proposed in the 2004 review. Based on current understanding, the key toxicological and human health issues that are likely to influence a health-based recommendation relate to: neurotoxicology; reproductive and developmental toxicology; and mutagenicity/carcinogenicity. Of these, it is generally considered that neurotoxicity presents the most sensitive endpoint. As such, many of the studies that have been reported since the IEH review have sought to use those neurofunctional tests that appear to be particularly sensitive at identifying the subtle neurological changes thought to associate with manganese toxicity. These recent studies have, however, continued to be limited to a significant extent by reliance on cross-sectional designs and also by use of unreliable exposure estimation methods. Consequently the strength of the potential association between manganese exposure and these subtle subclinical cognitive or neuromotor changes is still poorly characterised and the relevance of these minor differences in terms of either their clinical or quality of life consequences remains unknown. Based upon the overall evidence, it is concluded that the 8-h time weighted averages (TWA) for respirable (0.05mg/m(3) as Mn) and inhalable (0.2mg/m(3) as Mn) fractions as recommended by the SCOEL in 2011 are the most methodologically-sound, as they are based on the best available studies, most suited to the

  14. Patient-based radiographic exposure factor selection: a systematic review

    SciTech Connect

    Ching, William; Robinson, John; McEntee, Mark

    2014-09-15

    Digital technology has wider exposure latitude and post-processing algorithms which can mask the evidence of underexposure and overexposure. Underexposure produces noisy, grainy images which can impede diagnosis and overexposure results in a greater radiation dose to the patient. These exposure errors can result from inaccurate adjustment of exposure factors in response to changes in patient thickness. This study aims to identify all published radiographic exposure adaptation systems which have been, or are being, used in general radiography and discuss their applicability to digital systems. Studies in EMBASE, MEDLINE, CINAHL and SCOPUS were systematically reviewed. Some of the search terms used were exposure adaptation, exposure selection, exposure technique, 25% rule, 15% rule, DuPont™ Bit System and radiography. A manual journal-specific search was also conducted in The Radiographer and Radiologic Technology. Studies were included if they demonstrated a system of altering exposure factors to compensate for variations in patients for general radiography. Studies were excluded if they focused on finding optimal exposures for an ‘average’ patient or focused on the relationship between exposure factors and dose. The database search uncovered 11 articles and the journal-specific search uncovered 13 articles discussing systems of exposure adaptation. They can be categorised as simple one-step guidelines, comprehensive charts and computer programs. Only two papers assessed the efficacy of exposure adjustment systems. No literature compares the efficacy of exposure adaptations system for film/screen radiography with digital radiography technology nor is there literature on a digital specific exposure adaptation system.

  15. Electric Vehicle Preparedness: Task 1, Assessment of Fleet Inventory for Marine Corps Base Camp Lejeune

    SciTech Connect

    Schey, Stephen; Francfort, Jim

    2015-01-01

    Several U.S. Department of Defense-based studies were conducted to identify potential U.S. Department of Defense transportation systems that are strong candidates for introduction or expansion of plug-in electric vehicles (PEVs). Task 1 included a survey of the inventory of non-tactical fleet vehicles at the Marine Corps Base Camp Lejeune (MCBCL) to characterize the fleet. This information and characterization will be used to select vehicles for monitoring that takes place during Task 2. This monitoring involves data logging of vehicle operation in order to identify the vehicle’s mission and travel requirements. Individual observations of these selected vehicles provide the basis for recommendations related to PEV adoption. It also identifies whether a battery electric vehicle or plug-in hybrid electric vehicle (collectively referred to as PEVs) can fulfill the mission requirements and provides observations related to placement of PEV charging infrastructure.

  16. A swarm intelligence based memetic algorithm for task allocation in distributed systems

    NASA Astrophysics Data System (ADS)

    Sarvizadeh, Raheleh; Haghi Kashani, Mostafa

    2012-01-01

    This paper proposes a Swarm Intelligence based Memetic algorithm for Task Allocation and scheduling in distributed systems. The tasks scheduling in distributed systems is known as an NP-complete problem. Hence, many genetic algorithms have been proposed for searching optimal solutions from entire solution space. However, these existing approaches are going to scan the entire solution space without considering the techniques that can reduce the complexity of the optimization. Spending too much time for doing scheduling is considered the main shortcoming of these approaches. Therefore, in this paper memetic algorithm has been used to cope with this shortcoming. With regard to load balancing efficiently, Bee Colony Optimization (BCO) has been applied as local search in the proposed memetic algorithm. Extended experimental results demonstrated that the proposed method outperformed the existing GA-based method in terms of CPU utilization.

  17. A swarm intelligence based memetic algorithm for task allocation in distributed systems

    NASA Astrophysics Data System (ADS)

    Sarvizadeh, Raheleh; Haghi Kashani, Mostafa

    2011-12-01

    This paper proposes a Swarm Intelligence based Memetic algorithm for Task Allocation and scheduling in distributed systems. The tasks scheduling in distributed systems is known as an NP-complete problem. Hence, many genetic algorithms have been proposed for searching optimal solutions from entire solution space. However, these existing approaches are going to scan the entire solution space without considering the techniques that can reduce the complexity of the optimization. Spending too much time for doing scheduling is considered the main shortcoming of these approaches. Therefore, in this paper memetic algorithm has been used to cope with this shortcoming. With regard to load balancing efficiently, Bee Colony Optimization (BCO) has been applied as local search in the proposed memetic algorithm. Extended experimental results demonstrated that the proposed method outperformed the existing GA-based method in terms of CPU utilization.

  18. Evaluation of various mental task combinations for near-infrared spectroscopy-based brain-computer interfaces.

    PubMed

    Hwang, Han-Jeong; Lim, Jeong-Hwan; Kim, Do-Won; Im, Chang-Hwan

    2014-01-01

    A number of recent studies have demonstrated that near-infrared spectroscopy (NIRS) is a promisingneuroimaging modality for brain-computer interfaces (BCIs). So far, most NIRS-based BCI studies have focusedon enhancing the accuracy of the classification of different mental tasks. In the present study, we evaluated theperformances of a variety of mental task combinations in order to determine the mental task pairs that are bestsuited for customized NIRS-based BCIs. To this end, we recorded event-related hemodynamic responses whileseven participants performed eight different mental tasks. Classification accuracies were then estimated for allpossible pairs of the eight mental tasks (8C2 = 28). Based on this analysis, mental task combinations with relatively high classification accuracies frequently included the following three mental tasks: “mental multiplication,” “mental rotation,” and “right-hand motor imagery.” Specifically, mental task combinations consisting of two of these three mental tasks showed the highest mean classification accuracies. It is expected that our results will be a useful reference to reduce the time needed for preliminary tests when discovering individual-specific mental task combinations.

  19. A Project to Develop Performance Based Instruction through Task Analysis and In-Service Programs. Final Report.

    ERIC Educational Resources Information Center

    Ledoux, Clarence E.

    The primary purposes of this project were to develop catalogs of performance objectives and performance guides based upon validated tasks performed by incumbent workers and to disseminate and diffuse catalogs through inservice activities. The five catalogs developed were based upon tasks performed in the occupations of banking clerk, diesel…

  20. The Relationship between Working Memory Capacity and L2 Oral Performance under Task-Based Careful Online Planning Condition

    ERIC Educational Resources Information Center

    Ahmadian, Mohammad Javad

    2012-01-01

    The study reported in this article aimed to investigate the way working memory capacity (WMC) interacts with careful online planning--a task-based implementation variable--to affect second language (L2) speech production. This issue is important to teachers, because it delves into one of the possible task-based implementation variables and thus…

  1. Gaining Proficiency through Task-Based Activities in the Portuguese Classroom (Beginning and Intermediate Year Case Studies)

    ERIC Educational Resources Information Center

    Jones-Kellogg, Rebecca

    2015-01-01

    This paper describes a task-based activity used at the United States Military Academy, in their first- through third-semester Portuguese language sequence "Proficiencies" (Proficiências). The stand-alone task-based activity can be an effective tool in gaining foreign-language proficiency at even the lowest levels of classroom instruction…

  2. Task-based detectability in CT image reconstruction by filtered backprojection and penalized likelihood estimation

    SciTech Connect

    Gang, Grace J.; Stayman, J. Webster; Zbijewski, Wojciech; Siewerdsen, Jeffrey H.

    2014-08-15

    Purpose: Nonstationarity is an important aspect of imaging performance in CT and cone-beam CT (CBCT), especially for systems employing iterative reconstruction. This work presents a theoretical framework for both filtered-backprojection (FBP) and penalized-likelihood (PL) reconstruction that includes explicit descriptions of nonstationary noise, spatial resolution, and task-based detectability index. Potential utility of the model was demonstrated in the optimal selection of regularization parameters in PL reconstruction. Methods: Analytical models for local modulation transfer function (MTF) and noise-power spectrum (NPS) were investigated for both FBP and PL reconstruction, including explicit dependence on the object and spatial location. For FBP, a cascaded systems analysis framework was adapted to account for nonstationarity by separately calculating fluence and system gains for each ray passing through any given voxel. For PL, the point-spread function and covariance were derived using the implicit function theorem and first-order Taylor expansion according toFessler [“Mean and variance of implicitly defined biased estimators (such as penalized maximum likelihood): Applications to tomography,” IEEE Trans. Image Process. 5(3), 493–506 (1996)]. Detectability index was calculated for a variety of simple tasks. The model for PL was used in selecting the regularization strength parameter to optimize task-based performance, with both a constant and a spatially varying regularization map. Results: Theoretical models of FBP and PL were validated in 2D simulated fan-beam data and found to yield accurate predictions of local MTF and NPS as a function of the object and the spatial location. The NPS for both FBP and PL exhibit similar anisotropic nature depending on the pathlength (and therefore, the object and spatial location within the object) traversed by each ray, with the PL NPS experiencing greater smoothing along directions with higher noise. The MTF of FBP

  3. Evidence-based practices for thromboembolism prevention: summary of the ASPS Venous Thromboembolism Task Force Report.

    PubMed

    Murphy, Robert X; Alderman, Amy; Gutowski, Karol; Kerrigan, Carolyn; Rosolowski, Karie; Schechter, Loren; Schmitz, Delaine; Wilkins, Edwin

    2012-07-01

    In July of 2011, the American Society of Plastic Surgeons Executive Committee approved the Venous Thromboembolism Task Force Report. The report includes a summary of the scientific literature relevant to venous thromboembolism and plastic surgery along with five evidence-based recommendations. The recommendations are divided into two sections: risk stratification and prevention. The risk stratification recommendations are based on the 2005 Caprini Risk Assessment Module, which has been validated in the scientific literature as an effective tool for risk-stratifying plastic and reconstructive surgery patients based on individual risk factors for 60-day venous thromboembolism. The three prophylaxis recommendations are dependent on an individual patient's 2005 Caprini Risk Assessment Module score.

  4. Analyzing Process Data from Game/Scenario-Based Tasks: An Edit Distance Approach

    ERIC Educational Resources Information Center

    Hao, Jiangang; Shu, Zhan; von Davier, Alina

    2015-01-01

    Students' activities in game/scenario-based tasks (G/SBTs) can be characterized by a sequence of time-stamped actions of different types with different attributes. For a subset of G/SBTs in which only the order of the actions is of great interest, the process data can be well characterized as a string of characters (i.e., action string) if we…

  5. Comparing Alternative Computer-Based Methods for Preventing Job Task Instructions

    DTIC Science & Technology

    1988-02-01

    NAME OF MONITORING ORGANIZATION U.S. Army Research Institute, PERI-MB ^ c ADDRESS (Ofy, State, and ZIP Code) San Diego, CA 92152-6800 7b...COMPARING ALTERNATIVE COMPUTER-BASED METHODS FOR PRESENTING 30B TASK INSTRUCTIONS William A. Nugent Approved by Richard C . Sorenson Released by B. E...RELATED SUPPORT EQUIPMENT B-0 APPENDIX C -EXAMPLE OF A PERFORMANCE OBSERVATION FORM C -0 APPENDIX D-EXAMINEE WORKSHEET FORM D-0 APPENDIX E

  6. A novel task-oriented optimal design for P300-based brain-computer interfaces.

    PubMed

    Zhou, Zongtan; Yin, Erwei; Liu, Yang; Jiang, Jun; Hu, Dewen

    2014-10-01

    Objective. The number of items of a P300-based brain-computer interface (BCI) should be adjustable in accordance with the requirements of the specific tasks. To address this issue, we propose a novel task-oriented optimal approach aimed at increasing the performance of general P300 BCIs with different numbers of items. Approach. First, we proposed a stimulus presentation with variable dimensions (VD) paradigm as a generalization of the conventional single-character (SC) and row-column (RC) stimulus paradigms. Furthermore, an embedding design approach was employed for any given number of items. Finally, based on the score-P model of each subject, the VD flash pattern was selected by a linear interpolation approach for a certain task. Main results. The results indicate that the optimal BCI design consistently outperforms the conventional approaches, i.e., the SC and RC paradigms. Specifically, there is significant improvement in the practical information transfer rate for a large number of items. Significance. The results suggest that the proposed optimal approach would provide useful guidance in the practical design of general P300-based BCIs.

  7. SpECTRE: A task-based discontinuous Galerkin code for relativistic astrophysics

    NASA Astrophysics Data System (ADS)

    Kidder, Lawrence E.; Field, Scott E.; Foucart, Francois; Schnetter, Erik; Teukolsky, Saul A.; Bohn, Andy; Deppe, Nils; Diener, Peter; Hébert, François; Lippuner, Jonas; Miller, Jonah; Ott, Christian D.; Scheel, Mark A.; Vincent, Trevor

    2017-04-01

    We introduce a new relativistic astrophysics code, SpECTRE, that combines a discontinuous Galerkin method with a task-based parallelism model. SpECTRE's goal is to achieve more accurate solutions for challenging relativistic astrophysics problems such as core-collapse supernovae and binary neutron star mergers. The robustness of the discontinuous Galerkin method allows for the use of high-resolution shock capturing methods in regions where (relativistic) shocks are found, while exploiting high-order accuracy in smooth regions. A task-based parallelism model allows efficient use of the largest supercomputers for problems with a heterogeneous workload over disparate spatial and temporal scales. We argue that the locality and algorithmic structure of discontinuous Galerkin methods will exhibit good scalability within a task-based parallelism framework. We demonstrate the code on a wide variety of challenging benchmark problems in (non)-relativistic (magneto)-hydrodynamics. We demonstrate the code's scalability including its strong scaling on the NCSA Blue Waters supercomputer up to the machine's full capacity of 22 , 380 nodes using 671 , 400 threads.

  8. Population-Based Assessment of Exposure to Risk Behaviors in Motion Pictures.

    PubMed

    Sargent, James D; Worth, Keilah A; Beach, Michael; Gerrard, Meg; Heatherton, Todd F

    2008-01-01

    The aim of most population-based studies of media is to relate a specific exposure to an outcome of interest. A research program has been developed that evaluates exposure to different components of movies in an attempt of assess the association of such exposure with the adoption of substance use during adolescence. To assess exposure to movie substance use, one must measure both viewing time and content. In developing the exposure measure, the study team was interested in circumventing a common problem in exposure measurement, where measures often conflate exposure to media with attention to media. Our aim in this paper is to present a validated measure of exposure to entertainment media, the Beach method, which combines recognition of a movie title with content analysis of the movie for substance use, to generate population based measures of exposure to substance use in this form of entertainment.

  9. Report of the Defense Science Board Task Force on Defense Science and Technology Base for the 21st Century

    DTIC Science & Technology

    2016-06-07

    Reference directed that the Task Force make recommendations on these issues: - The proper funding level for the Science and Technology program - The...REPORT OF THE DEFENSE SCIENCE BOARD TASK FORCE ON DEFENSE SCIENCE AND TECHNOLOGY BASE FOR THE 21ST CENTURY June 1998 OFFICE OF THE UNDER...number. 1. REPORT DATE 30 JUN 1998 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Report of the Defense Science Board Task

  10. Feasibility of performing space surveillance tasks with a proposed space-based optical architecture

    NASA Astrophysics Data System (ADS)

    Flohrer, T.; Krag, H.; Klinkrad, H.; Schildknecht, T.

    2011-03-01

    Under ESA contract an industrial consortium including Aboa Space Research Oy (ASRO), the Astronomical Institute of the University of Bern (AIUB), and the Dutch National Aerospace Laboratory (NLR), proposed the observation concept, developed a suitable sensor architecture, and assessed the performance of a space-based optical (SBO) telescope in 2005. The goal of the SBO study was to analyse how the existing knowledge gap in the space debris population in the millimetre and centimetre regime may be closed by means of a passive optical instrument. The SBO instrument was requested to provide statistical information on the space debris population in terms of number of objects and size distribution. The SBO instrument was considered to be a cost-efficient with 20 cm aperture and 6° field-of-view and having flexible integration requirements. It should be possible to integrate the SBO instrument easily as a secondary payload on satellites launched into low-Earth orbits (LEO), or into geostationary orbit (GEO). Thus the selected mission concept only allowed for fix-mounted telescopes, and the pointing direction could be requested freely. Since 2007 ESA focuses space surveillance and tracking activities in the Space Situational Awareness (SSA) preparatory program. Ground-based radars and optical telescopes are studied for the build-up and maintenance of a catalogue of objects. In this paper we analyse how the proposed SBO architecture could contribute to the space surveillance tasks survey and tracking. We assume that the SBO instrumentation is placed into a circular sun-synchronous orbit at 800 km altitude. We discuss the observation conditions of objects at higher altitude, and select an orbit close to the terminator plane. A pointing of the sensor orthogonal to the orbital plane with optimal elevation slightly in positive direction (0° and +5°) is found optimal for accessing the entire GEO regime within one day, implying a very good coverage of controlled objects in

  11. Fast Gaussian kernel learning for classification tasks based on specially structured global optimization.

    PubMed

    Zhong, Shangping; Chen, Tianshun; He, Fengying; Niu, Yuzhen

    2014-09-01

    For a practical pattern classification task solved by kernel methods, the computing time is mainly spent on kernel learning (or training). However, the current kernel learning approaches are based on local optimization techniques, and hard to have good time performances, especially for large datasets. Thus the existing algorithms cannot be easily extended to large-scale tasks. In this paper, we present a fast Gaussian kernel learning method by solving a specially structured global optimization (SSGO) problem. We optimize the Gaussian kernel function by using the formulated kernel target alignment criterion, which is a difference of increasing (d.i.) functions. Through using a power-transformation based convexification method, the objective criterion can be represented as a difference of convex (d.c.) functions with a fixed power-transformation parameter. And the objective programming problem can then be converted to a SSGO problem: globally minimizing a concave function over a convex set. The SSGO problem is classical and has good solvability. Thus, to find the global optimal solution efficiently, we can adopt the improved Hoffman's outer approximation method, which need not repeat the searching procedure with different starting points to locate the best local minimum. Also, the proposed method can be proven to converge to the global solution for any classification task. We evaluate the proposed method on twenty benchmark datasets, and compare it with four other Gaussian kernel learning methods. Experimental results show that the proposed method stably achieves both good time-efficiency performance and good classification performance.

  12. Extraversion differentiates between model-based and model-free strategies in a reinforcement learning task.

    PubMed

    Skatova, Anya; Chan, Patricia A; Daw, Nathaniel D

    2013-01-01

    Prominent computational models describe a neural mechanism for learning from reward prediction errors, and it has been suggested that variations in this mechanism are reflected in personality factors such as trait extraversion. However, although trait extraversion has been linked to improved reward learning, it is not yet known whether this relationship is selective for the particular computational strategy associated with error-driven learning, known as model-free reinforcement learning, vs. another strategy, model-based learning, which the brain is also known to employ. In the present study we test this relationship by examining whether humans' scores on an extraversion scale predict individual differences in the balance between model-based and model-free learning strategies in a sequentially structured decision task designed to distinguish between them. In previous studies with this task, participants have shown a combination of both types of learning, but with substantial individual variation in the balance between them. In the current study, extraversion predicted worse behavior across both sorts of learning. However, the hypothesis that extraverts would be selectively better at model-free reinforcement learning held up among a subset of the more engaged participants, and overall, higher task engagement was associated with a more selective pattern by which extraversion predicted better model-free learning. The findings indicate a relationship between a broad personality orientation and detailed computational learning mechanisms. Results like those in the present study suggest an intriguing and rich relationship between core neuro-computational mechanisms and broader life orientations and outcomes.

  13. Autonomy, competence, and social relatedness in task interest within project-based education.

    PubMed

    Minnaert, Alexander; Boekaerts, Monique; de Brabander, Cornelis

    2007-10-01

    To prepare students for instructive collaboration, it is necessary to have insight into students' psychological needs and interest development. The framework of self-determination theory was used to conduct a field experiment involving 114 students in vocational education. These students followed a practical business course which required they work in small learning groups. During the course, students were asked to complete the Quality of Working in Groups Instrument, an online measure of how strong autonomy, competence, social relatedness, and task interest are fulfilled. SEM showed that students' psychological needs were jointly and uniquely related to task interest over time. The significance of this on-line test for the assessment of interest within project-based education is discussed.

  14. Spatial learning in a virtual reality-based task is altered in very preterm children.

    PubMed

    Cimadevilla, José M; Roldán, Lola; París, María; Arnedo, Marisa; Roldán, Susana

    2014-01-01

    Very preterm births prevent a complete development of the nervous system. The hippocampus is especially vulnerable in this population since the perinatal period is critical for its growth and development. Learning and memory abilities, like spatial memory, depend on the hippocampal integrity. In this study we applied virtual-reality-based tasks to assess spatial memory in a sample of 20 very preterm children of 7 and 8 years of age. Two different conditions of difficulty were used. Very preterm children performed poorly in the task in comparison with the control group. They committed more errors than controls searching for the rewarded positions. However, no significant differences were observed in the mean speed, an index of the motor abilities and joystick handling. These results suggest that the hippocampal function is affected in this sample. Nevertheless, other variables to consider are discussed.

  15. Age differences in strategic behavior during a computation-based skill acquisition task.

    PubMed

    Touron, Dayna R; Hertzog, Christopher

    2009-09-01

    The authors evaluated mechanistic and metacognitive accounts of age differences in strategy transitions during skill acquisition. Old and young participants were trained on a task involving a shift from performing a novel arithmetic algorithm to responding via associative recognition of equation-solution pairings. The strategy shift was manipulated by task instructions that either (a) equally focused on speed and accuracy, (b) encouraged retrieval use as a method toward fast responding, or (c) offered monetary incentives for fast retrieval-based performance. Monetary incentives produced a more rapid shift to retrieval relative to standard instructions; older adults showed a greater incentives effect on retrieval use than younger adults. Monetary incentives encouraged retrieval use and response time improvements despite accuracy costs (a speed-accuracy tradeoff). The pattern of results suggested a role of metacognitive and volitional factors in retrieval shift, indicating that an associative learning deficit cannot fully account for older adults' delayed strategy shift.

  16. Structural foundations of resting-state and task-based functional connectivity in the human brain.

    PubMed

    Hermundstad, Ann M; Bassett, Danielle S; Brown, Kevin S; Aminoff, Elissa M; Clewett, David; Freeman, Scott; Frithsen, Amy; Johnson, Arianne; Tipper, Christine M; Miller, Michael B; Grafton, Scott T; Carlson, Jean M

    2013-04-09

    Magnetic resonance imaging enables the noninvasive mapping of both anatomical white matter connectivity and dynamic patterns of neural activity in the human brain. We examine the relationship between the structural properties of white matter streamlines (structural connectivity) and the functional properties of correlations in neural activity (functional connectivity) within 84 healthy human subjects both at rest and during the performance of attention- and memory-demanding tasks. We show that structural properties, including the length, number, and spatial location of white matter streamlines, are indicative of and can be inferred from the strength of resting-state and task-based functional correlations between brain regions. These results, which are both representative of the entire set of subjects and consistently observed within individual subjects, uncover robust links between structural and functional connectivity in the human brain.

  17. Multiple ocular diseases detection based on joint sparse multi-task learning.

    PubMed

    Chen, Xiangyu; Xu, Yanwu; Yin, Fengshou; Zhang, Zhuo; Wong, Damon Wing Kee; Wong, Tien Yin; Liu, Jiang

    2015-01-01

    In this paper, we present a multiple ocular diseases detection scheme based on joint sparse multi-task learning. Glaucoma, Pathological Myopia (PM), and Age-related Macular Degeneration (AMD) are three major causes of vision impairment and blindness worldwide. The proposed joint sparse multitask learning framework aims to reconstruct a test fundus image with multiple features from as few training subjects as possible. The linear version of this problem could be casted into a multi-task joint covariate selection model, which can be very efficiently optimized via kernelizable accelerated proximal gradient method. Extensive experiments are conducted in order to validate the proposed framework on the SiMES dataset. From the Area Under Curve (AUC) results in multiple ocular diseases classification, our method is shown to outperform the state-of-the-art algorithms.

  18. Utilization Assessment of Target Electrification Vehicles at Marine Corps Base Camp Lejeune. Task 3

    SciTech Connect

    Schey, Stephen; Francfort, Jim

    2015-11-01

    Battelle Energy Alliance, LLC, managing and operating contractor for the U.S. Department of Energy’s Idaho National Laboratory, is the lead laboratory for U.S. Department of Energy Advanced Vehicle Testing. Battelle Energy Alliance, LLC contracted with Intertek Testing Services, North America (Intertek) to conduct several U.S. Department of Defense base studies to identify potential U.S. Department of Defense transportation systems that are strong candidates for introduction or expansion of plug-in electric vehicles (PEVs). Task 1 consisted of a survey of the non-tactical fleet of vehicles at MCBCL to begin the review of vehicle mission assignments and types of vehicles in service. Task 2 involved identifying daily operational characteristics of select vehicles and initiating data logging of vehicle movements in order to characterize the vehicle’s mission. Individual observations of these selected vehicles provide the basis for recommendations related to PEV adoption and whether a battery electric vehicle or plug-in hybrid electric vehicle (collectively referred to as PEVs) can fulfill the mission requirements and provide observations related to placement of PEV charging infrastructure. This report provides the results of the data analysis and observations related to replacement of current vehicles with PEVs. This fulfills part of the Task 3 requirements. Task 3 also includes an assessment of the charging infrastructure required to support this replacement, which is the subject of a separate report. Intertek acknowledges the support of Idaho National Laboratory, Marine Corps headquarters, and Marine Corps Base Camp Lejeune Fleet management and personnel for participation in this study. Intertek is pleased to provide this report and is encouraged by enthusiasm and support from MCBCL personnel.

  19. Development of saliva-based exposure assays for detecting exposure to waterborne pathogens

    EPA Pesticide Factsheets

    Identifying which pathogens we are exposed to can be challenging because many types of pathogens can be found in water and many pathogens have similar symptoms. EPA scientists have developed a simple way to measure human exposure to waterborne pathogens.

  20. Chemical process based reconstruction of exposures for an epidemiological study. III. Analysis of industrial hygiene samples.

    PubMed

    Hall, Thomas A; Esmen, Nurtan A; Jones, Elizabeth P; Basara, Heather; Phillips, Margaret L; Marsh, Gary M; Youk, Ada O; Buchanich, Jeanine M; Leonard, Robin C

    2007-03-20

    As part of an historical cohort study to investigate the mortality experience of industrial workers exposed to chloroprene (beta-CD) and other substances, all available industrial hygiene exposure monitoring data were collected and summarized. From discussions with on-site industrial hygiene personnel, it was apparent that these data were not collected for epidemiological purposes and, therefore, their use in characterization of exposures was problematic as the data mostly pertained to samples collected to investigate the performance of specific tasks. These data were, however, informative for validating the exposure modeling process used to estimate historical exposures. The data summarized below clearly indicate that exposures to beta-CD were lowered across the time period of this study. Typically, the exposures recorded were less than the occupational exposure limits of the periods in which the exposures were recorded. Additionally, exposure measurements recorded in the recent past do not represent the exposure actually experienced by the worker as a strict personal protective equipment use program has been in place for the facilities studied since the mid-1980s.

  1. The interacting role of media violence exposure and aggressive-disruptive behavior in adolescent brain activation during an emotional Stroop task.

    PubMed

    Kalnin, Andrew J; Edwards, Chad R; Wang, Yang; Kronenberger, William G; Hummer, Tom A; Mosier, Kristine M; Dunn, David W; Mathews, Vincent P

    2011-04-30

    Only recently have investigations of the relationship between media violence exposure (MVE) and aggressive behavior focused on brain functioning. In this study, we examined the relationship between brain activation and history of media violence exposure in adolescents, using functional magnetic resonance imaging (fMRI). Samples of adolescents with no psychiatric diagnosis or with disruptive behavior disorder (DBD) with aggression were compared to investigate whether the association of MVE history and brain activation is moderated by aggressive behavior/personality. Twenty-two adolescents with a history of aggressive behavior and diagnosis of either conduct disorder or oppositional-defiant disorder (DBD sample) and 22 controls completed an emotional Stroop task during fMRI. Primary imaging results indicated that controls with a history of low MVE demonstrated greater activity in the right inferior frontal gyrus and rostral anterior cingulate during the violent word condition. In contrast, in adolescents with DBD, those with high MVE exhibited decreased activation in the right amygdala, compared with those with low MVE. These findings are consistent with research demonstrating the importance of fronto-limbic structures for processing emotional stimuli, and with research suggesting that media violence may affect individuals in different ways depending on the presence of aggressive traits.

  2. Feature-based attentional modulation increases with stimulus separation in divided-attention tasks.

    PubMed

    Sally, Sharon L; Vidnyánsky, Zoltán; Papathomas, Thomas V

    2009-01-01

    Attention modifies our visual experience by selecting certain aspects of a scene for further processing. It is therefore important to understand factors that govern the deployment of selective attention over the visual field. Both location and feature-specific mechanisms of attention have been identified and their modulatory effects can interact at a neural level (Treue and Martinez-Trujillo, 1999). The effects of spatial parameters on feature-based attentional modulation were examined for the feature dimensions of orientation, motion and color using three divided-attention tasks. Subjects performed concurrent discriminations of two briefly presented targets (Gabor patches) to the left and right of a central fixation point at eccentricities of +/-2.5 degrees , 5 degrees , 10 degrees and 15 degrees in the horizontal plane. Gabors were size-scaled to maintain consistent single-task performance across eccentricities. For all feature dimensions, the data show a linear increase in the attentional effects with target separation. In a control experiment, Gabors were presented on an isoeccentric viewing arc at 10 degrees and 15 degrees at the closest spatial separation (+/-2.5 degrees ) of the main experiment. Under these conditions, the effects of feature-based attentional effects were largely eliminated. Our results are consistent with the hypothesis that feature-based attention prioritizes the processing of attended features. Feature-based attentional mechanisms may have helped direct the attentional focus to the appropriate target locations at greater separations, whereas similar assistance may not have been necessary at closer target spacings. The results of the present study specify conditions under which dual-task performance benefits from sharing similar target features and may therefore help elucidate the processes by which feature-based attention operates.

  3. The impact of cognitive control on children's goal monitoring in a time-based prospective memory task.

    PubMed

    Mahy, Caitlin E V; Voigt, Babett; Ballhausen, Nicola; Schnitzspahn, Katharina; Ellis, Judi; Kliegel, Matthias

    2015-01-01

    The present study investigated whether developmental changes in cognitive control may underlie improvements of time-based prospective memory. Five-, 7-, 9-, and 11-year-olds (N = 166) completed a driving simulation task (ongoing task) in which they had to refuel their vehicle at specific points in time (PM task). The availability of cognitive control resources was experimentally manipulated by imposing a secondary task that required divided attention. Children completed the driving simulation task both in a full-attention condition and a divided-attention condition where they had to carry out a secondary task. Results revealed that older children performed better than younger children on the ongoing task and PM task. Children performed worse on the ongoing and PM tasks in the divided-attention condition compared to the full-attention condition. With respect to time monitoring in the final interval prior to the PM target, divided attention interacted with age such that older children's time monitoring was more negatively affected by the secondary task compared to younger children. Results are discussed in terms of developmental shifts from reactive to proactive monitoring strategies.

  4. Comparing alternative computer-based methods for presenting job-task instructions. Interim report, May 1986-May 1987

    SciTech Connect

    Nugent, W.A.

    1988-02-01

    This study compared the effects of previous task training/experience and alternative methods for presenting procedural instructions on job-task performance. Six computer-based methods were examined by having oscilloscope operators perform four equipment-related tasks. The presentation methods were text-only, audio-only, text-audio, text-graphics, audio-training and experience in operating oscilloscopes. The most-efficient and effective task performances were obtained through a combination of audio and graphic presentations, an effect which can be further enhanced by the addition of redundant textual instructions. The practical applications and theoretical implications of these findings are discussed.

  5. Complexity Measures, Task Type, and Analytic Evaluations of Speaking Proficiency in a School-Based Assessment Context

    ERIC Educational Resources Information Center

    Gan, Zhengdong

    2012-01-01

    This study, which is part of a large-scale study of using objective measures to validate assessment rating scales and assessment tasks in a high-profile school-based assessment initiative in Hong Kong, examined how grammatical complexity measures relate to task type and analytic evaluations of students' speaking proficiency in a classroom-based…

  6. A Tentative Study on the Task-Based Teaching of Writing to English Majors in Chinese Settings

    ERIC Educational Resources Information Center

    Zhaochun, Sun

    2015-01-01

    Under task-based learning (TBL) framework, language learners engage in purposeful, problem-oriented, and outcome-driven tasks that are comparable to traditional teaching methods which focus only on the correctness of grammar. In this study, the author employs Jane Willis' TBL framework and examines its effects on the improvement of EFL learners'…

  7. Web-Based Undergraduate Chemistry Problem-Solving: The Interplay of Task Performance, Domain Knowledge and Web-Searching Strategies

    ERIC Educational Resources Information Center

    She, Hsiao-Ching; Cheng, Meng-Tzu; Li, Ta-Wei; Wang, Chia-Yu; Chiu, Hsin-Tien; Lee, Pei-Zon; Chou, Wen-Chi; Chuang, Ming-Hua

    2012-01-01

    This study investigates the effect of Web-based Chemistry Problem-Solving, with the attributes of Web-searching and problem-solving scaffolds, on undergraduate students' problem-solving task performance. In addition, the nature and extent of Web-searching strategies students used and its correlation with task performance and domain knowledge also…

  8. The Impact of Task-Based Instruction Program on Fostering ESL Learners' Speaking Ability: A Cognitive Approach

    ERIC Educational Resources Information Center

    Mohammadipour, Mohammad; Rashid, Sabariah Md.

    2015-01-01

    Adopting a direct approach to contrive sufficient focus on form (accuracy) would facilitate interlanguage development without decreasing the naturalness of communication that communicative tasks can generate. This study aimed to determine the effectiveness of a proposed task-based instruction programme within a cognitive approach in fostering…

  9. An Online Task-Based Language Learning Environment: Is It Better for Advanced- or Intermediate-Level Second Language Learners?

    ERIC Educational Resources Information Center

    Arslanyilmaz, Abdurrahman

    2012-01-01

    This study investigates the relationship of language proficiency to language production and negotiation of meaning that non-native speakers (NNSs) produced in an online task-based language learning (TBLL) environment. Fourteen NNS-NNS dyads collaboratively completed four communicative tasks, using an online TBLL environment specifically designed…

  10. Task-based modeling and optimization of a cone-beam CT scanner for musculoskeletal imaging

    SciTech Connect

    Prakash, P.; Zbijewski, W.; Gang, G. J.; Ding, Y.; Stayman, J. W.; Yorkston, J.; Carrino, J. A.; Siewerdsen, J. H.

    2011-10-15

    Purpose: This work applies a cascaded systems model for cone-beam CT imaging performance to the design and optimization of a system for musculoskeletal extremity imaging. The model provides a quantitative guide to the selection of system geometry, source and detector components, acquisition techniques, and reconstruction parameters. Methods: The model is based on cascaded systems analysis of the 3D noise-power spectrum (NPS) and noise-equivalent quanta (NEQ) combined with factors of system geometry (magnification, focal spot size, and scatter-to-primary ratio) and anatomical background clutter. The model was extended to task-based analysis of detectability index (d') for tasks ranging in contrast and frequency content, and d' was computed as a function of system magnification, detector pixel size, focal spot size, kVp, dose, electronic noise, voxel size, and reconstruction filter to examine trade-offs and optima among such factors in multivariate analysis. The model was tested quantitatively versus the measured NPS and qualitatively in cadaver images as a function of kVp, dose, pixel size, and reconstruction filter under conditions corresponding to the proposed scanner. Results: The analysis quantified trade-offs among factors of spatial resolution, noise, and dose. System magnification (M) was a critical design parameter with strong effect on spatial resolution, dose, and x-ray scatter, and a fairly robust optimum was identified at M {approx} 1.3 for the imaging tasks considered. The results suggested kVp selection in the range of {approx}65-90 kVp, the lower end (65 kVp) maximizing subject contrast and the upper end maximizing NEQ (90 kVp). The analysis quantified fairly intuitive results--e.g., {approx}0.1-0.2 mm pixel size (and a sharp reconstruction filter) optimal for high-frequency tasks (bone detail) compared to {approx}0.4 mm pixel size (and a smooth reconstruction filter) for low-frequency (soft-tissue) tasks. This result suggests a specific protocol for

  11. Paired-Associate and Feedback-Based Weather Prediction Tasks Support Multiple Category Learning Systems

    PubMed Central

    Li, Kaiyun; Fu, Qiufang; Sun, Xunwei; Zhou, Xiaoyan; Fu, Xiaolan

    2016-01-01

    It remains unclear whether probabilistic category learning in the feedback-based weather prediction task (FB-WPT) can be mediated by a non-declarative or procedural learning system. To address this issue, we compared the effects of training time and verbal working memory, which influence the declarative learning system but not the non-declarative learning system, in the FB and paired-associate (PA) WPTs, as the PA task recruits a declarative learning system. The results of Experiment 1 showed that the optimal accuracy in the PA condition was significantly decreased when the training time was reduced from 7 to 3 s, but this did not occur in the FB condition, although shortened training time impaired the acquisition of explicit knowledge in both conditions. The results of Experiment 2 showed that the concurrent working memory task impaired the optimal accuracy and the acquisition of explicit knowledge in the PA condition but did not influence the optimal accuracy or the acquisition of self-insight knowledge in the FB condition. The apparent dissociation results between the FB and PA conditions suggested that a non-declarative or procedural learning system is involved in the FB-WPT and provided new evidence for the multiple-systems theory of human category learning. PMID:27445958

  12. Creating Task-Centered Instruction for Web-Based Instruction: Obstacles and Solutions

    ERIC Educational Resources Information Center

    Gardner, Joel; Jeon, Tae

    2010-01-01

    Merrill proposes First Principles of Instruction, including a problem- or task-centered strategy for designing instruction. However, when the tasks or problems are ill-defined or complex, task-centered instruction can be difficult to design. We describe an online task-centered training at a land-grant university designed to train employees to use…

  13. Development of the town data base: Estimates of exposure rates and times of fallout arrival near the Nevada Test Site

    SciTech Connect

    Thompson, C.B.; McArthur, R.D.; Hutchinson, S.W.

    1994-09-01

    As part of the U.S. Department of Energy`s Off-Site Radiation Exposure Review Project, the time of fallout arrival and the H+12 exposure rate were estimated for populated locations in Arizona, California, Nevada, and Utah that were affected by fallout from one or more nuclear tests at the Nevada Test Site. Estimates of exposure rate were derived from measured values recorded before and after each test by fallout monitors in the field. The estimate for a given location was obtained by retrieving from a data base all measurements made in the vicinity, decay-correcting them to H+12, and calculating an average. Estimates were also derived from maps produced after most events that show isopleths of exposure rate and time of fallout arrival. Both sets of isopleths on these maps were digitized, and kriging was used to interpolate values at the nodes of a 10-km grid covering the pattern. The values at any location within the grid were then estimated from the values at the surrounding grid nodes. Estimates of dispersion (standard deviation) were also calculated. The Town Data Base contains the estimates for all combinations of location and nuclear event for which the estimated mean H+12 exposure rate was greater than three times background. A listing of the data base is included as an appendix. The information was used by other project task groups to estimate the radiation dose that off-site populations and individuals may have received as a result of exposure to fallout from Nevada nuclear tests.

  14. A Neurophysiological examination of quality of learning in a feedback-based learning task.

    PubMed

    Arbel, Yael; Wu, Hao

    2016-12-01

    The efficiency with which one processes external feedback contributes to the speed and quality of one's learning. Previous findings that the feedback related negativity (FRN) event related potential (ERP) is modulated by learning outcomes suggested that this ERP reflects the extent to which feedback is used by the learner to improve performance. To further test this suggestion, we measured whether the FRN and the fronto-central positivity (FCP) that follows it are modulated by learning slopes, and as a function of individual differences in learning outcomes. Participants were tasked with learning names (non-words) of 42 novel objects in a two-choice feedback-based visual learning task. The items were divided into three sets of 14 items, each presented in five learning blocks and a sixth test block. Individual learning slopes based on performance on the task, as well as FRN and FCP slopes based on positive and negative feedback related activation in each block were created for 53 participants. Our data pointed to an interaction between slopes of the FRN elicited by negative feedback and learning slopes, such that a sharper decrease in the amplitude of the FRN to negative feedback was associated with sharper learning slopes. We further examined the predictive power of the FRN and FCP elicited in the training blocks on the learning outcomes as measured by performance on the test blocks. We found that small FRN to negative feedback, large FRN to positive feedback, and large FCP to negative feedback in the first training block predicted better learning outcomes. These results add to the growing evidence that the processes giving rise to the FRN and FCP are sensitive to individual differences in the extent to which feedback is used for learning.

  15. Implementation Approach for Electric Vehicles at Marine Corps Base Camp Lejeune. Task 4

    SciTech Connect

    Schey, Stephen; Francfort, Jim

    2015-11-01

    Battelle Energy Alliance, LLC, managing and operating contractor for the U.S. Department of Energy’s Idaho National Laboratory, is the lead laboratory for U.S. Department of Energy Advanced Vehicle Testing. Battelle Energy Alliance, LLC contracted with Intertek Testing Services, North America (Intertek) to conduct several U.S. Department of Defense base studies to identify potential U.S. Department of Defense transportation systems that are strong candidates for introduction or expansion of plug-in electric vehicles (PEVs). This study is focused on the Marine Corps Base Camp Lejeune (MCBCL) located in North Carolina. Task 1 consisted of a survey of the non-tactical fleet of vehicles at MCBCL to begin the review of vehicle mission assignments and types of vehicles in service. In Task 2, daily operational characteristics of vehicles were identified to select vehicles for further monitoring and attachment of data loggers. Task 3 recorded vehicle movements in order to characterize the vehicles’ missions. The results of the data analysis and observations were provided. Individual observations of the selected vehicles provided the basis for recommendations related to PEV adoption, i.e., whether a battery electric vehicle (BEV) or plug-in hybrid electric vehicle (PHEV) (collectively PEVs) can fulfill the mission requirements. It also provided the basis for recommendations related to placement of PEV charging infrastructure. This report focuses on an implementation plan for the near-term adoption of PEVs into the MCBCL fleet. Intertek acknowledges the support of Idaho National Laboratory, Marine Corps headquarters, and Marine Corps Base Camp Lejeune fleet management and personnel for participation in this study. Intertek is pleased to provide this report and is encouraged by enthusiasm and support from MCBCL personnel.

  16. A graphical workstation based part-task flight simulator for preliminary rapid evaluation of advanced displays

    NASA Technical Reports Server (NTRS)

    Wanke, Craig; Kuchar, James; Hahn, Edward; Pritchett, Amy; Hansman, R. J.

    1992-01-01

    Advances in avionics and display technology are significantly changing the cockpit environment in current transport aircraft. The MIT Aeronautical Systems Lab (ASL) has developed a part-task flight simulator specifically to study the effects of these new technologies on flight crew situational awareness and performance. The simulator is based on a commercially-available graphics workstation, and can be rapidly reconfigured to meet the varying demands of experimental studies. The simulator has been successfully used to evaluate graphical microburst alerting displays, electronic instrument approach plates, terrain awareness and alerting displays, and ATC routing amendment delivery through digital datalinks.

  17. A graphical workstation based part-task flight simulator for preliminary rapid evaluation of advanced displays

    NASA Technical Reports Server (NTRS)

    Wanke, Craig; Kuchar, James; Hahn, Edward; Pritchett, A.; Hansman, R. John

    1994-01-01

    Advances in avionics and display technology are significantly changing the cockpit environment in current transport aircraft. The MIT Aeronautical Systems Lab (ASL) developed a part-task flight simulator specifically to study the effects of these new technologies on flight crew situational awareness and performance. The simulator is based on a commercially-available graphics workstation, and can be rapidly reconfigured to meet the varying demands of experimental studies. The simulator was successfully used to evaluate graphical microbursts alerting displays, electronic instrument approach plates, terrain awareness and alerting displays, and ATC routing amendment delivery through digital datalinks.

  18. Figure of merit for task-based assessment of frequency-domain diffusive imaging.

    PubMed

    Kang, DongYel; Kupinski, Matthew A

    2013-01-15

    A figure of merit (FOM) for frequency-domain diffusive imaging (FDDI) is theoretically developed adapting the concept of Hotelling observer signal-to-noise ratio. Different from conventionally used FOMs for FDDI, the newly developed FOM considers diffused intensities, modulation amplitudes, and phases in combination. The FOM applied to Monte Carlo simulations of signal- and background-known-exactly problems shows unique characteristics that are in agreement with findings in the literature. We believe that a task based assessment using the FOM improves the characterization of FDDI systems and allows for complete system optimization.

  19. Task-specific noise exposure during manual concrete surface grinding in enclosed areas-influence of operation variables and dust control methods.

    PubMed

    Akbar-Khanzadeh, Farhang; Ames, April L; Milz, Sheryl A; Akbar-Khanzadeh, Mahboubeh

    2013-01-01

    Noise exposure is a distinct hazard during hand-held concrete grinding activities, and its assessment is challenging because of the many variables involved. Noise dosimeters were used to examine the extent of personal noise exposure while concrete grinding was performed with a variety of grinder sizes, types, accessories, and available dust control methods. Noise monitoring was conducted in an enclosed area covering 52 task-specific grinding sessions lasting from 6 to 72 minutes. Noise levels, either in minute average noise level (Lavg, dBA) or in minute peak (dBC), during concrete grinding were significantly (P < 0.01) correlated with general ventilation (GV: on, off), dust control methods (uncontrolled, wet, Shop-Vac, HEPA, HEPA-Cyclone), grinding cup wheel (blade) sizes of 4-inch (100 mm), 5-inch (125 mm) and 6-inch (150 mm), and surface orientation (horizontal, inclined). Overall, minute Lavg during grinding was 97.0 ± 3.3 (mean ± SD), ranging from 87.9 to 113. The levels of minute Lavg during uncontrolled grinding (98.9 ± 5.2) or wet-grinding (98.5 ± 2.7) were significantly higher than those during local exhaust ventilation (LEV) grinding (96.2 ± 2.8). A 6-inch grinding cup wheel generated significantly higher noise levels (98.7 ± 2.8) than 5-inch (96.3 ± 3.2) or 4-inch (95.3 ± 3.5) cup wheels. The minute peak noise levels (dBC) during grinding was 113 ± 5.2 ranging from 104 to 153. The minute peak noise levels during uncontrolled grinding (119 ± 10.2) were significantly higher than those during wet-grinding (115 ± 4.5) and LEV-grinding (112 ± 3.4). A 6-inch grinding cup wheel generated significantly higher minute peak noise levels (115 ± 5.3) than 5-inch (112 ± 4.5) or 4-inch (111 ± 5.4) cup wheels. Assuming an 8-hour work shift, the results indicated that noise exposure levels during concrete grinding in enclosed areas exceeded the recommended permissible exposure limits and workers should be protected by engineering control methods, safe

  20. Population Based Exposure Assessment of Bioaccessible Arsenic in Carrots

    EPA Science Inventory

    The two predominant arsenic exposure routes are food and water. Estimating the risk from dietary exposures is complicated, owing to the chemical form dependent toxicity of arsenic and the diversity of arsenicals present in dietary matrices. Two aspects of assessing dietary expo...

  1. Ex Priori: Exposure-based Prioritization across Chemical Space

    EPA Science Inventory

    EPA's Exposure Prioritization (Ex Priori) is a simplified, quantitative visual dashboard that makes use of data from various inputs to provide rank-ordered internalized dose metric. This complements other high throughput screening by viewing exposures within all chemical space si...

  2. Using Agent-Based Approaches to Characterize Exposure Related Behavior

    EPA Science Inventory

    The Tox21 initiative is generating data on biological activity, toxicity, and chemical properties for over 8,000 substances. One of the goals for EPA’s National Exposure Research Lab (NERL) is to assess the magnitude and variability in the public’s exposures to these ...

  3. Adaptive Baseline Enhances EM-Based Policy Search: Validation in a View-Based Positioning Task of a Smartphone Balancer

    PubMed Central

    Wang, Jiexin; Uchibe, Eiji; Doya, Kenji

    2017-01-01

    EM-based policy search methods estimate a lower bound of the expected return from the histories of episodes and iteratively update the policy parameters using the maximum of a lower bound of expected return, which makes gradient calculation and learning rate tuning unnecessary. Previous algorithms like Policy learning by Weighting Exploration with the Returns, Fitness Expectation Maximization, and EM-based Policy Hyperparameter Exploration implemented the mechanisms to discard useless low-return episodes either implicitly or using a fixed baseline determined by the experimenter. In this paper, we propose an adaptive baseline method to discard worse samples from the reward history and examine different baselines, including the mean, and multiples of SDs from the mean. The simulation results of benchmark tasks of pendulum swing up and cart-pole balancing, and standing up and balancing of a two-wheeled smartphone robot showed improved performances. We further implemented the adaptive baseline with mean in our two-wheeled smartphone robot hardware to test its performance in the standing up and balancing task, and a view-based approaching task. Our results showed that with adaptive baseline, the method outperformed the previous algorithms and achieved faster, and more precise behaviors at a higher successful rate. PMID:28167910

  4. Is creative insight task-specific? A coordinate-based meta-analysis of neuroimaging studies on insightful problem solving.

    PubMed

    Shen, Wangbing; Yuan, Yuan; Liu, Chang; Zhang, Xiaojiang; Luo, Jing; Gong, Zhe

    2016-12-01

    The question of whether creative insight varies across problem types has recently come to the forefront of studies of creative cognition. In the present study, to address the nature of creative insight, the coordinate-based activation likelihood estimation (ALE) technique was utilized to individually conduct three quantitative meta-analyses of neuroimaging experiments that used the compound remote associate (CRA) task, the prototype heuristic (PH) task and the Chinese character chunk decomposition (CCD) task. These tasks were chosen because they are frequently used to uncover the neurocognitive correlates of insight. Our results demonstrated that creative insight reliably activates largely non-overlapping brain regions across task types, with the exception of some shared regions: the CRA task mainly relied on the right parahippocampal gyrus, the superior frontal gyrus and the inferior frontal gyrus; the PH task primarily depended on the right middle occipital gyrus (MOG), the bilateral superior parietal lobule/precuneus, the left inferior parietal lobule, the left lingual gyrus and the left middle frontal gyrus; and the CCD task activated a broad cerebral network consisting of most dorsolateral and medial prefrontal regions, frontoparietal regions and the right MOG. These results provide the first neural evidence of the task dependence of creative insight. The implications of these findings for resolving conflict surrounding the different theories of creative cognition and for defining insight as a set of heterogeneous processes are discussed.

  5. Factors affecting outdoor exposure in winter: population-based study

    NASA Astrophysics Data System (ADS)

    Mäkinen, Tiina M.; Raatikka, Veli-Pekka; Rytkönen, Mika; Jokelainen, Jari; Rintamäki, Hannu; Ruuhela, Reija; Näyhä, Simo; Hassi, Juhani

    2006-09-01

    The extent of outdoor exposure during winter and factors affecting it were examined in a cross-sectional population study in Finland. Men and women aged 25-74 years from the National FINRISK 2002 sub-study ( n=6,591) were queried about their average weekly occupational, leisure-time and total cold exposure during the past winter. The effects of gender, age, area of residence, occupation, ambient temperature, self-rated health, physical activity and education on cold exposure were analysed. The self-reported median total cold exposure time was 7 h/week (8 h men, 6 h women),<1 h/week (2 h men, 0 h women) at work, 4 h/week (5 h men, 4 h women) during leisure time and 1 h/week (1 h men, 1.5 h women) while commuting to work. Factors associated with increased occupational cold exposure among men were: being employed in agriculture, forestry and industry/mining/construction or related occupations, being less educated and being aged 55-64 years. Factors associated with increased leisure-time cold exposure among men were: employment in industry/mining/construction or related occupations, being a pensioner or unemployed, reporting at least average health, being physically active and having college or vocational education. Among women, being a housewife, pensioner or unemployed and engaged in physical activity increased leisure-time cold exposure, and young women were more exposed than older ones. Self-rated health was positively associated with leisure time cold exposure in men and only to a minor extent in women. In conclusion, the subjects reported spending 4% of their total time under cold exposure, most of it (71%) during leisure time. Both occupational and leisure-time cold exposure is greater among men than women.

  6. Proportional reasoning as a heuristic-based process: time constraint and dual task considerations.

    PubMed

    Gillard, Ellen; Van Dooren, Wim; Schaeken, Walter; Verschaffel, Lieven

    2009-01-01

    The present study interprets the overuse of proportional solution methods from a dual process framework. Dual process theories claim that analytic operations involve time-consuming executive processing, whereas heuristic operations are fast and automatic. In two experiments to test whether proportional reasoning is heuristic-based, the participants solved "proportional" problems, for which proportional solution methods provide correct answers, and "nonproportional" problems known to elicit incorrect answers based on the assumption of proportionality. In Experiment 1, the available solution time was restricted. In Experiment 2, the executive resources were burdened with a secondary task. Both manipulations induced an increase in proportional answers and a decrease in correct answers to nonproportional problems. These results support the hypothesis that the choice for proportional methods is heuristic-based.

  7. Comparison of Modeling Approaches to Prioritize Chemicals Based on Estimates of Exposure and Exposure Potential

    EPA Science Inventory

    While only limited data are available to characterize the potential toxicity of over 8 million commercially available chemical substances, there is even less information available on the exposure and use-scenarios that are required to link potential toxicity to human and ecologic...

  8. Extraversion differentiates between model-based and model-free strategies in a reinforcement learning task

    PubMed Central

    Skatova, Anya; Chan, Patricia A.; Daw, Nathaniel D.

    2013-01-01

    Prominent computational models describe a neural mechanism for learning from reward prediction errors, and it has been suggested that variations in this mechanism are reflected in personality factors such as trait extraversion. However, although trait extraversion has been linked to improved reward learning, it is not yet known whether this relationship is selective for the particular computational strategy associated with error-driven learning, known as model-free reinforcement learning, vs. another strategy, model-based learning, which the brain is also known to employ. In the present study we test this relationship by examining whether humans' scores on an extraversion scale predict individual differences in the balance between model-based and model-free learning strategies in a sequentially structured decision task designed to distinguish between them. In previous studies with this task, participants have shown a combination of both types of learning, but with substantial individual variation in the balance between them. In the current study, extraversion predicted worse behavior across both sorts of learning. However, the hypothesis that extraverts would be selectively better at model-free reinforcement learning held up among a subset of the more engaged participants, and overall, higher task engagement was associated with a more selective pattern by which extraversion predicted better model-free learning. The findings indicate a relationship between a broad personality orientation and detailed computational learning mechanisms. Results like those in the present study suggest an intriguing and rich relationship between core neuro-computational mechanisms and broader life orientations and outcomes. PMID:24027514

  9. Studying hemispheric lateralization during a Stroop task through near-infrared spectroscopy-based connectivity

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Sun, Jinyan; Sun, Bailei; Luo, Qingming; Gong, Hui

    2014-05-01

    Near-infrared spectroscopy (NIRS) is a developing and promising functional brain imaging technology. Developing data analysis methods to effectively extract meaningful information from collected data is the major bottleneck in popularizing this technology. In this study, we measured hemodynamic activity of the prefrontal cortex (PFC) during a color-word matching Stroop task using NIRS. Hemispheric lateralization was examined by employing traditional activation and novel NIRS-based connectivity analyses simultaneously. Wavelet transform coherence was used to assess intrahemispheric functional connectivity. Spearman correlation analysis was used to examine the relationship between behavioral performance and activation/functional connectivity, respectively. In agreement with activation analysis, functional connectivity analysis revealed leftward lateralization for the Stroop effect and correlation with behavioral performance. However, functional connectivity was more sensitive than activation for identifying hemispheric lateralization. Granger causality was used to evaluate the effective connectivity between hemispheres. The results showed increased information flow from the left to the right hemispheres for the incongruent versus the neutral task, indicating a leading role of the left PFC. This study demonstrates that the NIRS-based connectivity can reveal the functional architecture of the brain more comprehensively than traditional activation, helping to better utilize the advantages of NIRS.

  10. A Knowledge-Based Strategy for the Automated Support to Network Management Tasks

    NASA Astrophysics Data System (ADS)

    Abar, Sameera; Kinoshita, Tetsuo

    This paper presents a domain-ontology driven multi-agent based scheme for representing the knowledge of the communication network management system. In the proposed knowledge-intensive framework, the static domain-related concepts are articulated as the domain knowledge ontology. The experiential knowledge for managing the network is represented as the fault-case reasoning models, and it is explicitly encoded as the core knowledge of multi-agent middleware layer as heuristic production-type rules. These task-oriented management expertise manipulates the domain content and structure during the diagnostic sessions. The agents' rules along with the embedded generic java-based problem-solving algorithms and run-time log information, perform the automated management tasks. For the proof of concept, an experimental network system has been implemented in our laboratory, and the deployment of some test-bed scenarios is performed. Experimental results confirm a marked reduction in the management-overhead of the network administrator, as compared to the manual network management techniques, in terms of the time-taken and effort-done during a particular fault-diagnosis session. Validation of the reusability/modifiability aspects of our system, illustrates the flexible manipulation of the knowledge fragments within diverse application contexts. The proposed approach can be regarded as one of the pioneered steps towards representing the network knowledge via reusable domain ontology and intelligent agents for the automated network management support systems.

  11. Application of ensemble classifier in EEG-based motor imagery tasks

    NASA Astrophysics Data System (ADS)

    Liu, Bianhong; Hao, Hongwei

    2007-12-01

    Electroencephalogram (EEG) recorded during motor imagery tasks can be used to move a cursor to a target on a computer screen. Such an EEG-based brain-computer interface (BCI) can provide a new communication channel for the subjects with neuromuscular disorders. To achieve higher speed and more accuracy to enhance the practical applications of BCI in computer aid medical systems, the ensemble classifier is used for the single classification. The ERDs at the electrodes C3 and C4 are calculated and then stacked together into the feature vector for the ensemble classifier. The ensemble classifier is based on Linear Discriminant Analysis (LDA) and Nearest Neighbor (NN). Furthermore, it considers the feedback. This method is successfully used in the 2003 international data analysis competition on BCI-tasks (data set III). The results show that the ensemble classifier succeed with a recognition as 90%, on average, which is 5% and 3% higher than that of using the LDA and NN separately. Moreover, the ensemble classifier outperforms LDA and NN in the whole time course. With adequate recognition, ease of use and clearly understood, the ensemble classifier can meet the need of time-requires for single classification.

  12. Prometheus: Scalable and Accurate Emulation of Task-Based Applications on Many-Core Systems.

    SciTech Connect

    Kestor, Gokcen; Gioiosa, Roberto; Chavarría-Miranda, Daniel

    2015-03-01

    Modeling the performance of non-deterministic parallel applications on future many-core systems requires the development of novel simulation and emulation techniques and tools. We present “Prometheus”, a fast, accurate and modular emulation framework for task-based applications. By raising the level of abstraction and focusing on runtime synchronization, Prometheus can accurately predict applications’ performance on very large many-core systems. We validate our emulation framework against two real platforms (AMD Interlagos and Intel MIC) and report error rates generally below 4%. We, then, evaluate Prometheus’ performance and scalability: our results show that Prometheus can emulate a task-based application on a system with 512K cores in 11.5 hours. We present two test cases that show how Prometheus can be used to study the performance and behavior of systems that present some of the characteristics expected from exascale supercomputer nodes, such as active power management and processors with a high number of cores but reduced cache per core.

  13. Task-Based Regularization Design for Detection of Intracranial Hemorrhage in Cone-Beam CT

    PubMed Central

    Dang, H.; Stayman, J. W.; Xu, J.; Sisniega, A.; Zbijewski, W.; Wang, X.; Foos, D. H.; Aygun, N.; Koliatsos, V. E.; Siewerdsen, J. H.

    2016-01-01

    Prompt and reliable detection of acute intracranial hemorrhage (ICH) is critical to treatment of a number of neurological disorders. Cone-beam CT (CBCT) systems are potentially suitable for detecting ICH (contrast 40-80 HU, size down to 1 mm) at the point of care but face major challenges in image quality requirements. Statistical reconstruction demonstrates improved noise-resolution tradeoffs in CBCT head imaging, but its capability in improving image quality with respect to the task of ICH detection remains to be fully investigated. Moreover, statistical reconstruction typically exhibits nonuniform spatial resolution and noise characteristics, leading to spatially varying detectability of ICH for a conventional penalty. In this work, we propose a spatially varying penalty design that maximizes detectability of ICH at each location throughout the image. We leverage theoretical analysis of spatial resolution and noise for a penalized weighted least-squares (PWLS) estimator, and employ a task-based imaging performance descriptor in terms of detectability index using a nonprewhitening observer model. Performance prediction was validated using a 3D anthropomorphic head phantom. The proposed penalty achieved superior detectability throughout the head and improved detectability in regions adjacent to the skull base by ~10% compared to a conventional uniform penalty. PWLS reconstruction with the proposed penalty demonstrated excellent visualization of simulated ICH in different regions of the head and provides further support for development of dedicated CBCT head scanning at the point-of-care in the neuro ICU and OR.

  14. An integrated utility-based model of conflict evaluation and resolution in the Stroop task.

    PubMed

    Chuderski, Adam; Smolen, Tomasz

    2016-04-01

    Cognitive control allows humans to direct and coordinate their thoughts and actions in a flexible way, in order to reach internal goals regardless of interference and distraction. The hallmark test used to examine cognitive control is the Stroop task, which elicits both the weakly learned but goal-relevant and the strongly learned but goal-irrelevant response tendencies, and requires people to follow the former while ignoring the latter. After reviewing the existing computational models of cognitive control in the Stroop task, its novel, integrated utility-based model is proposed. The model uses 3 crucial control mechanisms: response utility reinforcement learning, utility-based conflict evaluation using the Festinger formula for assessing the conflict level, and top-down adaptation of response utility in service of conflict resolution. Their complex, dynamic interaction led to replication of 18 experimental effects, being the largest data set explained to date by 1 Stroop model. The simulations cover the basic congruency effects (including the response latency distributions), performance dynamics and adaptation (including EEG indices of conflict), as well as the effects resulting from manipulations applied to stimulation and responding, which are yielded by the extant Stroop literature.

  15. Prospective and Retrospective Time Estimates of Children: A Comparison Based on Ecological Tasks

    PubMed Central

    Bisson, Nicolas; Tobin, Simon; Grondin, Simon

    2012-01-01

    Children's time estimation literature lacks of studies comparing prospective and retrospective time estimates of long lasting ecological tasks, i.e. tasks reflecting children's daily activities. In the present study, children were asked to estimate prospectively or retrospectively how much time they played a video game or read a magazine. Regardless of the task, the results revealed that prospective time estimates were longer than the retrospective ones. Also, time estimates of the video game task were longer, less accurate and more variable than those of the reading task. The results are discussed in the light of the current literature about time estimation of long lasting ecological tasks. PMID:22412982

  16. Exposure estimates based on broadband ELF magnetic field measurements versus the ICNIRP multiple frequency rule.

    PubMed

    Paniagua, Jesús M; Rufo, Montaña; Jiménez, Antonio; Pachón, Fernando T; Carrero, Julián

    2015-02-01

    The evaluation of exposure to extremely low-frequency (ELF) magnetic fields using broadband measurement techniques gives satisfactory results when the field has essentially a single frequency. Nevertheless, magnetic fields are in most cases distorted by harmonic components. This work analyses the harmonic components of the ELF magnetic field in an outdoor urban context and compares the evaluation of the exposure based on broadband measurements with that based on spectral analysis. The multiple frequency rule of the International Commission on Non-ionizing Radiation Protection (ICNIRP) regulatory guidelines was applied. With the 1998 ICNIRP guideline, harmonics dominated the exposure with a 55% contribution. With the 2010 ICNIRP guideline, however, the primary frequency dominated the exposure with a 78% contribution. Values of the exposure based on spectral analysis were significantly higher than those based on broadband measurements. Hence, it is clearly necessary to determine the harmonic components of the ELF magnetic field to assess exposure in urban contexts.

  17. Estimating cognitive workload using wavelet entropy-based features during an arithmetic task.

    PubMed

    Zarjam, Pega; Epps, Julien; Chen, Fang; Lovell, Nigel H

    2013-12-01

    Electroencephalography (EEG) has shown promise as an indicator of cognitive workload; however, precise workload estimation is an ongoing research challenge. In this investigation, seven levels of workload were induced using an arithmetic task, and the entropy of wavelet coefficients extracted from EEG signals is shown to distinguish all seven levels. For a subject-independent multi-channel classification scheme, the entropy features achieved high accuracy, up to 98% for channels from the frontal lobes, in the delta frequency band. This suggests that a smaller number of EEG channels in only one frequency band can be deployed for an effective EEG-based workload classification system. Together with analysis based on phase locking between channels, these results consistently suggest increased synchronization of neural responses for higher load levels.

  18. Development and evaluation of a microprocessor-based ergonomic dosimeter for evaluating carpentry tasks.

    PubMed

    Bhattacharya, A; Warren, J; Teuschler, J; Dimov, M; Medvedovic, M; Lemasters, G

    1999-12-01

    This portable and self-contained lightweight microprocessor based Ergonomic Dosimeter is designed to collect continuously postural angles of the torso and the upper arm in the sagittal plane and the number of kneeling activities. Up to 4 h of task performance data can be stored in a non-volatile memory of the dosimeter, which can then be downloaded to a lap-top computer. The portable dosimeter was tested for test-retest reliability, compared with posture data obtained with a computer-based video analysis system and evaluated at a carpenter's apprentices school and at a construction site. The dosimeter was shown to be suitable for collecting posture and kneeling data for a prolonged period at construction sites.

  19. Metaheuristic Based Scheduling Meta-Tasks in Distributed Heterogeneous Computing Systems

    PubMed Central

    Izakian, Hesam; Abraham, Ajith; Snášel, Václav

    2009-01-01

    Scheduling is a key problem in distributed heterogeneous computing systems in order to benefit from the large computing capacity of such systems and is an NP-complete problem. In this paper, we present a metaheuristic technique, namely the Particle Swarm Optimization (PSO) algorithm, for this problem. PSO is a population-based search algorithm based on the simulation of the social behavior of bird flocking and fish schooling. Particles fly in problem search space to find optimal or near-optimal solutions. The scheduler aims at minimizing makespan, which is the time when finishes the latest task. Experimental studies show that the proposed method is more efficient and surpasses those of reported PSO and GA approaches for this problem. PMID:22346701

  20. Metaheuristic based scheduling meta-tasks in distributed heterogeneous computing systems.

    PubMed

    Izakian, Hesam; Abraham, Ajith; Snášel, Václav

    2009-01-01

    Scheduling is a key problem in distributed heterogeneous computing systems in order to benefit from the large computing capacity of such systems and is an NP-complete problem. In this paper, we present a metaheuristic technique, namely the Particle Swarm Optimization (PSO) algorithm, for this problem. PSO is a population-based search algorithm based on the simulation of the social behavior of bird flocking and fish schooling. Particles fly in problem search space to find optimal or near-optimal solutions. The scheduler aims at minimizing makespan, which is the time when finishes the latest task. Experimental studies show that the proposed method is more efficient and surpasses those of reported PSO and GA approaches for this problem.

  1. Imaging Tasks Scheduling for High-Altitude Airship in Emergency Condition Based on Energy-Aware Strategy

    PubMed Central

    Zhimeng, Li; Chuan, He; Dishan, Qiu; Jin, Liu; Manhao, Ma

    2013-01-01

    Aiming to the imaging tasks scheduling problem on high-altitude airship in emergency condition, the programming models are constructed by analyzing the main constraints, which take the maximum task benefit and the minimum energy consumption as two optimization objectives. Firstly, the hierarchy architecture is adopted to convert this scheduling problem into three subproblems, that is, the task ranking, value task detecting, and energy conservation optimization. Then, the algorithms are designed for the sub-problems, and the solving results are corresponding to feasible solution, efficient solution, and optimization solution of original problem, respectively. This paper makes detailed introduction to the energy-aware optimization strategy, which can rationally adjust airship's cruising speed based on the distribution of task's deadline, so as to decrease the total energy consumption caused by cruising activities. Finally, the application results and comparison analysis show that the proposed strategy and algorithm are effective and feasible. PMID:23864822

  2. Imaging tasks scheduling for high-altitude airship in emergency condition based on energy-aware strategy.

    PubMed

    Zhimeng, Li; Chuan, He; Dishan, Qiu; Jin, Liu; Manhao, Ma

    2013-01-01

    Aiming to the imaging tasks scheduling problem on high-altitude airship in emergency condition, the programming models are constructed by analyzing the main constraints, which take the maximum task benefit and the minimum energy consumption as two optimization objectives. Firstly, the hierarchy architecture is adopted to convert this scheduling problem into three subproblems, that is, the task ranking, value task detecting, and energy conservation optimization. Then, the algorithms are designed for the sub-problems, and the solving results are corresponding to feasible solution, efficient solution, and optimization solution of original problem, respectively. This paper makes detailed introduction to the energy-aware optimization strategy, which can rationally adjust airship's cruising speed based on the distribution of task's deadline, so as to decrease the total energy consumption caused by cruising activities. Finally, the application results and comparison analysis show that the proposed strategy and algorithm are effective and feasible.

  3. Articulating uncertainty as part of scientific argumentation during model-based exoplanet detection tasks

    NASA Astrophysics Data System (ADS)

    Lee, Hee-Sun; Pallant, Amy; Pryputniewicz, Sarah

    2015-08-01

    Teaching scientific argumentation has emerged as an important goal for K-12 science education. In scientific argumentation, students are actively involved in coordinating evidence with theory based on their understanding of the scientific content and thinking critically about the strengths and weaknesses of the cited evidence in the context of the investigation. We developed a one-week-long online curriculum module called "Is there life in space?" where students conduct a series of four model-based tasks to learn how scientists detect extrasolar planets through the “wobble” and transit methods. The simulation model allows students to manipulate various parameters of an imaginary star and planet system such as planet size, orbit size, planet-orbiting-plane angle, and sensitivity of telescope equipment, and to adjust the display settings for graphs illustrating the relative velocity and light intensity of the star. Students can use model-based evidence to formulate an argument on whether particular signals in the graphs guarantee the presence of a planet. Students' argumentation is facilitated by the four-part prompts consisting of multiple-choice claim, open-ended explanation, Likert-scale uncertainty rating, and open-ended uncertainty rationale. We analyzed 1,013 scientific arguments formulated by 302 high school student groups taught by 7 teachers. We coded these arguments in terms of the accuracy of their claim, the sophistication of explanation connecting evidence to the established knowledge base, the uncertainty rating, and the scientific validity of uncertainty. We found that (1) only 18% of the students' uncertainty rationale involved critical reflection on limitations inherent in data and concepts, (2) 35% of students' uncertainty rationale reflected their assessment of personal ability and knowledge, rather than scientific sources of uncertainty related to the evidence, and (3) the nature of task such as the use of noisy data or the framing of

  4. Effects of virtual reality-based training and task-oriented training on balance performance in stroke patients

    PubMed Central

    Lee, Hyung Young; Kim, You Lim; Lee, Suk Min

    2015-01-01

    [Purpose] This study aimed to investigate the clinical effects of virtual reality-based training and task-oriented training on balance performance in stroke patients. [Subjects and Methods] The subjects were randomly allocated to 2 groups: virtual reality-based training group (n = 12) and task-oriented training group (n = 12). The patients in the virtual reality-based training group used the Nintendo Wii Fit Plus, which provided visual and auditory feedback as well as the movements that enabled shifting of weight to the right and left sides, for 30 min/day, 3 times/week for 6 weeks. The patients in the task-oriented training group practiced additional task-oriented programs for 30 min/day, 3 times/week for 6 weeks. Patients in both groups also underwent conventional physical therapy for 60 min/day, 5 times/week for 6 weeks. [Results] Balance and functional reach test outcomes were examined in both groups. The results showed that the static balance and functional reach test outcomes were significantly higher in the virtual reality-based training group than in the task-oriented training group. [Conclusion] This study suggested that virtual reality-based training might be a more feasible and suitable therapeutic intervention for dynamic balance in stroke patients compared to task-oriented training. PMID:26180341

  5. Effects of virtual reality-based training and task-oriented training on balance performance in stroke patients.

    PubMed

    Lee, Hyung Young; Kim, You Lim; Lee, Suk Min

    2015-06-01

    [Purpose] This study aimed to investigate the clinical effects of virtual reality-based training and task-oriented training on balance performance in stroke patients. [Subjects and Methods] The subjects were randomly allocated to 2 groups: virtual reality-based training group (n = 12) and task-oriented training group (n = 12). The patients in the virtual reality-based training group used the Nintendo Wii Fit Plus, which provided visual and auditory feedback as well as the movements that enabled shifting of weight to the right and left sides, for 30 min/day, 3 times/week for 6 weeks. The patients in the task-oriented training group practiced additional task-oriented programs for 30 min/day, 3 times/week for 6 weeks. Patients in both groups also underwent conventional physical therapy for 60 min/day, 5 times/week for 6 weeks. [Results] Balance and functional reach test outcomes were examined in both groups. The results showed that the static balance and functional reach test outcomes were significantly higher in the virtual reality-based training group than in the task-oriented training group. [Conclusion] This study suggested that virtual reality-based training might be a more feasible and suitable therapeutic intervention for dynamic balance in stroke patients compared to task-oriented training.

  6. Adaptation of a clustered lumpy background model for task-based image quality assessment in x-ray phase-contrast mammography

    PubMed Central

    Zysk, Adam M.; Brankov, Jovan G.; Wernick, Miles N.; Anastasio, Mark A.

    2012-01-01

    Purpose: Since the introduction of clinical x-ray phase-contrast mammography (PCM), a technique that exploits refractive-index variations to create edge enhancement at tissue boundaries, a number of optimization studies employing physical image-quality metrics have been performed. Ideally, task-based assessment of PCM would have been conducted with human readers. These studies have been limited, however, in part due to the large parameter-space of PCM system configurations and the difficulty of employing expert readers for large-scale studies. It has been proposed that numerical observers can be used to approximate the statistical performance of human readers, thus enabling the study of task-based performance over a large parameter-space. Methods: Methods are presented for task-based image quality assessment of PCM images with a numerical observer, the most significant of which is an adapted lumpy background from the conventional mammography literature that accounts for the unique wavefield propagation physics of PCM image formation and will be used with a numerical observer to assess image quality. These methods are demonstrated by performing a PCM task-based image quality study using a numerical observer. This study employs a signal-known-exactly, background-known-statistically Bayesian ideal observer method to assess the detectability of a calcification object in PCM images when the anode spot size and calcification diameter are varied. Results: The first realistic model for the structured background in PCM images has been introduced. A numerical study demonstrating the use of this background model has compared PCM and conventional mammography detection of calcification objects. The study data confirm the strong PCM calcification detectability dependence on anode spot size. These data can be used to balance the trade-off between enhanced image quality and the potential for motion artifacts that comes with use of a reduced spot size and increased exposure time

  7. Tactile refreshable screen based on magneto-rheological fluids for map exploration and navigation tasks

    NASA Astrophysics Data System (ADS)

    Bolzmacher, C.; Changeon, G.; Plaud, V.; Roselier, S.; Lozada, J.; Hafez, M.

    2011-06-01

    Human-machine interfaces can convey information via visual, audio and/or haptic cues during a navigation task. The visual and audio technologies are mature, whereas research has to be focused on haptic technologies for mobile devices. In this work, a tactile refreshable screen is proposed which allows its user the exploration of maps and navigational tasks in an egocentric perspective. The proposed device consists of an array of actuators which can display various patterns. The actuation technology is based on a magneto-rheological fluid which is injected in a chamber with an elastomeric membrane using a micro pump. The fluid pressure deforms the membrane in order to display a pattern. The fluid properties are used to form a valve in each cell. A permanent magnet, a ferromagnetic core, and a coil form a closed magnetic circuit with a gap where the magneto-rheological fluid can flow; the magnetic field interacts with the fluid and prevents the filling or draining of the chamber. Applying a current to the coil counteracts the magnetic field generated by the magnet and the fluid can circulate freely in order to inflate or deflate the membrane. The design, fabrication and integration of the device in addition to the results of finite element simulations and experimental measurements are reported.

  8. Effect of donepezil on reversal learning in a touch screen-based operant task.

    PubMed

    Chen, Woei-Shin; Wong, Fong-Kuan; Chapman, Paul F; Pemberton, Darrel J

    2009-10-01

    Impairments in reversal learning, which are commonly observed in patients with psychiatric disorders, remain difficult to treat. There is still a debate over the beneficial effects of cholinergic enhancers on improving behavioural flexibility. The objective of this study was to investigate the effect of an acetylcholinesterase inhibitor, donepezil, on the performance of a rodent Probabilistic Reversal Learning task. Lister-Hooded rats were trained to retrieve food rewards by discriminating two computer-generated stimuli in an automated touch screen-based operant task. When a steady performance was achieved, the stimulus-reward rule was reversed. Each rat was given a 30-min training session daily for 24 days and donepezil was administered 30 min before each training session. Systemic treatment with donepezil had no effect on trial accuracy of the two-stimulus discrimination training. However, the donepezil group showed enhanced performance in the reversal learning. Our result showed that treatment with donepezil significantly enhanced Probabilistic Reversal Learning performance in healthy animals. On the basis of this finding, the inhibition of the central acetylcholinesterase would seem to be a potential therapeutic approach to treat behavioural inflexibility.

  9. Historical limitations of determinant based exposure groupings in the rubber manufacturing industry

    PubMed Central

    Vermeulen, R; Kromhout, H

    2005-01-01

    Aims: To study the validity of using a cross-sectional industry-wide exposure survey to develop exposure groupings for epidemiological purposes that extend beyond the time period in which the exposure data were collected. Methods: Exposure determinants were used to group workers into high, medium, and low exposure groups. The contrast of this grouping and other commonly used grouping schemes based on plant and department within this exposure survey and a previously conducted survey within the same industry (and factories) were estimated and compared. Results: Grouping of inhalable and dermal exposure based on exposure determinants resulted in the highest, but still modest, contrast (ε ∼ 0.3). Classifying subjects based on a combination of plant and department resulted in a slightly lower contrast (ε ∼ 0.2). If the determinant based grouping derived from the 1997 exposure survey was used to classify workers in the 1988 survey the average contrast decreased significantly for both exposures (ε ∼ 0.1). On the contrary, the exposure classification based on plant and department increased in contrast (from ε ∼ 0.2 to ε ∼ 0.3) and retained its relative ranking overtime. Conclusions: Although determinant based groupings seem to result in more efficient groupings within a cross-sectional survey, they have to be used with caution as they might result in significant less contrast beyond the studied population or time period. It is concluded that a classification based on plant and department might be more desirable for retrospective studies in the rubber manufacturing industry, as they seem to have more historical relevance and are most likely more accurately recorded historically than information on exposure determinants in a particular industry. PMID:16234406

  10. Advanced Exposure Metrics For Chemical Risk Analysis: Systems Biology and 'Omic-based Biomarkers for Exposure Reconstruction

    EPA Science Inventory

    Direct measurement of human exposure to environmental contaminants in real time (when the exposure is actually occurring) is rare and difficult to obtain. This frustrates both exposure assessments and investigations into the linkage between chemical exposure and human disease. ...

  11. Derivation of safe health-based exposure limits for potential consumer exposure to styrene migrating into food from food containers.

    PubMed

    Gelbke, Heinz-Peter; Banton, Marcy; Faes, Eric; Leibold, Edgar; Pemberton, Mark; Duhayon, Sophie

    2014-02-01

    Residual styrene present in polystyrene food packaging may migrate into food at low levels. To assure safe use, safe exposure levels are derived for consumers potentially exposed via food using No/Low Adverse Effect Levels from animal and human studies and assessment factors proposed by European organisations (EFSA, ECHA, ECETOC). Ototoxicity and developmental toxicity in rats and human ototoxicity and effects on colour discrimination have been identified as the most relevant toxicological properties for styrene health assessments. Safe exposure levels derived from animal studies with assessment factors of EFSA and ECHA were expectedly much lower than those using the ECETOC approach. Comparable safe exposure levels were obtained from human data with all sets of assessment factors while ototoxicity in rats led to major differences. The safe exposure levels finally selected based on criteria of science and health protection converged to the range of 90-120 mg/person/d. Assuming a consumption of 1 kg food/d for an adult, this translates to 90 mg styrene migration into 1 kg food as safe for consumers. This assessment supports a health based Specific Migration Limit of 90 ppm, a value somewhat higher than the current overall migration limit of 60 ppm in the European Union.

  12. Measuring novices' field mapping abilities using an in-class exercise based on expert task analysis

    NASA Astrophysics Data System (ADS)

    Caulkins, J. L.

    2010-12-01

    We are interested in developing a model of expert-like behavior for improving the teaching methods of undergraduate field geology. Our aim is to assist students in mastering the process of field mapping more efficiently and effectively and to improve their ability to think creatively in the field. To examine expert-mapping behavior, a cognitive task analysis was conducted with expert geologic mappers in an attempt to define the process of geologic mapping (i.e. to understand how experts carry out geological mapping). The task analysis indicates that expert mappers have a wealth of geologic scenarios at their disposal that they compare against examples seen in the field, experiences that most undergraduate mappers will not have had. While presenting students with many geological examples in class may increase their understanding of geologic processes, novices still struggle when presented with a novel field situation. Based on the task analysis, a short (45-minute) paper-map-based exercise was designed and tested with 14 pairs of 3rd year geology students. The exercise asks students to generate probable geologic models based on a series of four (4) data sets. Each data set represents a day’s worth of data; after the first “day,” new sheets simply include current and previously collected data (e.g. “Day 2” data set includes data from “Day 1” plus the new “Day 2” data). As the geologic complexity increases, students must adapt, reject or generate new geologic models in order to fit the growing data set. Preliminary results of the exercise indicate that students who produced more probable geologic models, and produced higher ratios of probable to improbable models, tended to go on to do better on the mapping exercises at the 3rd year field school. These results suggest that those students with more cognitively available geologic models may be more able to use these models in field settings than those who are unable to draw on these models for whatever

  13. Prioritization of pesticides based on daily dietary exposure potential as determined from the SHEDS model.

    PubMed

    Melnyk, Lisa Jo; Wang, Zhaohui; Li, Zhilin; Xue, Jianping

    2016-10-01

    A major pathway for exposure to many pesticides is through diet. The objectives were to rank pesticides by comparing their calculated daily dietary exposure as determined by EPA's Stochastic Human Exposure and Dose Simulation (SHEDS) to single pesticides for different age groups to acceptable daily intakes (ADI), characterize pesticide trends in exposures over different time periods, and determine commodities contributing to pesticide exposures. SHEDS was applied, using Pesticide Data Program (PDP) (1991-2011) and pesticide usage data on crops from USDA combined with NHANES dietary consumption data, to generate exposure estimates by age group. ADI data collected from EPA, WHO, and other sources were used to rank pesticides based on relativeness of the dietary exposure potential to ADI by age groups. Sensitivity analysis provided trends in pesticide exposures. Within SHEDS, commodities contributing the majority of pesticides with greatest exposure potential were determined. The results indicated that the highest ranking pesticides were methamidophos and diazinon which exceeded 100% of the ADI. Sensitivity analysis indicated that exposure to methamidophos, diazinon, malathion, ethion and formetanate hydrochloride had a marked decrease from 1991-1999 to 2000-2011. Contributions analysis indicated that apples, mushroom, carrots, and lettuce contributed to diazinon exposure. Beans and pepper contributed to methamidophos exposure.

  14. An Agent-Based Simulation for Investigating the Impact of Stereotypes on Task-Oriented Group Formation

    NASA Astrophysics Data System (ADS)

    Maghami, Mahsa; Sukthankar, Gita

    In this paper, we introduce an agent-based simulation for investigating the impact of social factors on the formation and evolution of task-oriented groups. Task-oriented groups are created explicitly to perform a task, and all members derive benefits from task completion. However, even in cases when all group members act in a way that is locally optimal for task completion, social forces that have mild effects on choice of associates can have a measurable impact on task completion performance. In this paper, we show how our simulation can be used to model the impact of stereotypes on group formation. In our simulation, stereotypes are based on observable features, learned from prior experience, and only affect an agent's link formation preferences. Even without assuming stereotypes affect the agents' willingness or ability to complete tasks, the long-term modifications that stereotypes have on the agents' social network impair the agents' ability to form groups with sufficient diversity of skills, as compared to agents who form links randomly. An interesting finding is that this effect holds even in cases where stereotype preference and skill existence are completely uncorrelated.

  15. A distributed computing environment with support for constraint-based task scheduling and scientific experimentation

    SciTech Connect

    Ahrens, J.P.; Shapiro, L.G.; Tanimoto, S.L.

    1997-04-01

    This paper describes a computing environment which supports computer-based scientific research work. Key features include support for automatic distributed scheduling and execution and computer-based scientific experimentation. A new flexible and extensible scheduling technique that is responsive to a user`s scheduling constraints, such as the ordering of program results and the specification of task assignments and processor utilization levels, is presented. An easy-to-use constraint language for specifying scheduling constraints, based on the relational database query language SQL, is described along with a search-based algorithm for fulfilling these constraints. A set of performance studies show that the environment can schedule and execute program graphs on a network of workstations as the user requests. A method for automatically generating computer-based scientific experiments is described. Experiments provide a concise method of specifying a large collection of parameterized program executions. The environment achieved significant speedups when executing experiments; for a large collection of scientific experiments an average speedup of 3.4 on an average of 5.5 scheduled processors was obtained.

  16. A model of task-deletion mechanism based on the priority queueing system of Barabási

    NASA Astrophysics Data System (ADS)

    Zhou, Bin; Xie, Jia-Rong; Yan, Xiao-Yong; Wang, Nianxin; Wang, Bing-Hong

    2017-01-01

    In this paper, we propose a model of task-deletion mechanism based on the priority queueing system of Barabási (2005) to deep research the pattern diversity of human behaviors. The analytical solution for our model with two tasks is presented. In different cases of the parameter of task-deletion, our model can produce rich statistical behavior patterns, which are consistent with lots of empirical studies. Therefore, the model can theoretically explain more human behavior phenomena than the model of Barabási. These results have important significance for understanding the mechanism of pattern diversity of human behaviors.

  17. Individual versus Interactive Task-Based Performance through Voice-Based Computer-Mediated Communication

    ERIC Educational Resources Information Center

    Granena, Gisela

    2016-01-01

    Interaction is a necessary condition for second language (L2) learning (Long, 1980, 1996). Research in computer-mediated communication has shown that interaction opportunities make learners pay attention to form in a variety of ways that promote L2 learning. This research has mostly investigated text-based rather than voice-based interaction. The…

  18. "Task" as Research Construct

    ERIC Educational Resources Information Center

    Seedhouse, Paul

    2005-01-01

    The article examines "task" as research construct as predominantly conceived in terms of task-as-workplan in the task-based learning/second language acquisition literature. It is suggested that "task" has weak construct validity and ontology in an overwhelmingly quantitative paradigm because the construct has a "split personality."…

  19. Lunar base applications of superconductivity: Lunar base systems study task 3.4

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The application of superconductor technology to several key aspects of an advanced-stage Lunar Base is described. Applications in magnetic energy storage, electromagnetic launching, and radiation shielding are discussed.

  20. Lunar base scenario cost estimates: Lunar base systems study task 6.1

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The projected development and production costs of each of the Lunar Base's systems are described and unit costs are estimated for transporting the systems to the lunar surface and for setting up the system.

  1. Lunar base applications of superconductivity: Lunar base systems study task 3. 4

    SciTech Connect

    Not Available

    1988-10-01

    The application of superconductor technology to several key aspects of an advanced-stage Lunar Base is described. Applications in magnetic energy storage, electromagnetic launching, and radiation shielding are discussed.

  2. MAX meets ADAM: a dosimetric comparison between a voxel-based and a mathematical model for external exposure to photons.

    PubMed

    Kramer, R; Vieira, J W; Khoury, H J; de Andrade Lima, F

    2004-03-21

    The International Commission on Radiological Protection intends to revise the organ and tissue equivalent dose conversion coefficients published in various reports. For this purpose the mathematical human medical internal radiation dose (MIRD) phantoms, actually in use, have to be replaced by recently developed voxel-based phantoms. This study investigates the dosimetric consequences, especially with respect to the effective male dose, if not only a MIRD phantom is replaced by a voxel phantom, but also if the tissue compositions and the radiation transport codes are changed. This task will be resolved by systematically replacing in the mathematical ADAM/GSF exposure model, first the radiation transport code, then the tissue composition and finally the phantom anatomy, in order to arrive at the voxel-based MAX/EGS4 exposure model. The results show that the combined effect of these replacements can decrease the effective male dose by up to 25% for external exposures to photons for incident energies above 30 keV for different field geometries, mainly because of increased shielding by a heterogeneous skeleton and by the overlying adipose and muscle tissue, and also because of the positions internal organs have in a realistically designed human body compared to their positions in the mathematically constructed phantom.

  3. Physiologically-based pharmacokinetic (PBPK) models in human exposure assessment

    SciTech Connect

    Krishnan, K.

    1995-12-31

    The potential dose received by an individual during defined exposure situations can be determined using personal dosimeters or estimated by combining information on exposure scenarios with the environmental concentration (C.) of chemicals. With the latter approach, not only the potential dose but also the internal dose (i.e., amount of chemical that has been absorbed and available for interaction with receptors) and biologically-effective dose (i.e., amount of chemical that actually reaches the cellular sites where interaction with macromolecules occur) can be estimated if C. is provided as an input to PBPK models. These models are mathematical representations of the interrelationships among the critical determinants of the absorption, distribution, metabolism and excretion of chemicals in biota. Since the compartments in this model correspond to biologically relevant tissues or tissue groups, the amount of chemical reaching specific target organ(s) can be estimated. Further, the PBPK models permit the use of biological monitoring data such as urinary levels of metabolites, hemoglobin adduct levels, and alveolar air concentrations, to reconstruct the exposure levels and scenarios for specific subgroups of populations. These models are also useful in providing estimates of target tissue dose in humans simultaneously exposed to chemicals in various media (air, water, soil, food) by different routes (oral, dermal, inhalation). Several examples of exposure assessment for volatile organic chemicals using PBPK models for mammals will be presented, and the strategies for development of these models for other classes of chemicals highlighted.

  4. A Decision Analytic Approach to Exposure-Based Chemical Prioritization

    EPA Science Inventory

    The manufacture of novel synthetic chemicals has increased in volume and variety, but often the environmental and health risks are not fully understood in terms of toxicity and, in particular, exposure. While efforts to assess risks have generally been effective when sufficient d...

  5. Worldwide flight and ground-based exposure of composite materials

    NASA Technical Reports Server (NTRS)

    Dexter, H. B.; Baker, D. J.

    1984-01-01

    The long-term durability of those advanced composite materials which are applicable to aircraft structures was discussed. The composite components of various military and commercial aircraft and helicopters were reviewed. Both ground exposure and flight service were assessed in terms of their impact upon composite structure durability. The ACEE Program is mentioned briefly.

  6. Performance impact of mutation operators of a subpopulation-based genetic algorithm for multi-robot task allocation problems.

    PubMed

    Liu, Chun; Kroll, Andreas

    2016-01-01

    Multi-robot task allocation determines the task sequence and distribution for a group of robots in multi-robot systems, which is one of constrained combinatorial optimization problems and more complex in case of cooperative tasks because they introduce additional spatial and temporal constraints. To solve multi-robot task allocation problems with cooperative tasks efficiently, a subpopulation-based genetic algorithm, a crossover-free genetic algorithm employing mutation operators and elitism selection in each subpopulation, is developed in this paper. Moreover, the impact of mutation operators (swap, insertion, inversion, displacement, and their various combinations) is analyzed when solving several industrial plant inspection problems. The experimental results show that: (1) the proposed genetic algorithm can obtain better solutions than the tested binary tournament genetic algorithm with partially mapped crossover; (2) inversion mutation performs better than other tested mutation operators when solving problems without cooperative tasks, and the swap-inversion combination performs better than other tested mutation operators/combinations when solving problems with cooperative tasks. As it is difficult to produce all desired effects with a single mutation operator, using multiple mutation operators (including both inversion and swap) is suggested when solving similar combinatorial optimization problems.

  7. Biology Based Lung Cancer Model for Chronic Low Radon Exposures

    NASA Astrophysics Data System (ADS)

    TruÅ£ǎ-Popa, Lucia-Adina; Hofmann, Werner; Fakir, Hatim; Cosma, Constantin

    2008-08-01

    Low dose effects of alpha particles at the tissue level are characterized by the interaction of single alpha particles, affecting only a small fraction of the cells within that tissue. Alpha particle intersections of bronchial target cells during a given exposure period were simulated by an initiation-promotion model, formulated in terms of cellular hits within the cycle time of the cell (dose-rate) and then integrated over the whole exposure period (dose). For a given average number of cellular hits during the lifetime of bronchial cells, the actual number of single and multiple hits was selected from a Poisson distribution. While oncogenic transformation is interpreted as the primary initiation step, stimulated mitosis by killing adjacent cells is assumed to be the primary radiological promotion event. Analytical initiation and promotion functions were derived from experimental in vitro data on oncogenic transformation and cellular survival. To investigate the shape of the lung cancer risk function at chronic, low level exposures in more detail, additional biological factors describing the tissue response and operating specifically at low doses were incorporated into the initiation-promotion model. These mechanisms modifying the initial response at the cellular level were: adaptive response, genomic instability, induction of apoptosis by surrounding cells, and detrimental as well as protective bystander mechanisms. To quantify the effects of these mechanisms as functions of dose, analytical functions were derived from the experimental evidence presently available. Predictions of lung cancer risk, including these mechanisms, exhibit a distinct sublinear dose-response relationship at low exposures, particularly for very low exposure rates.

  8. Non-linguistic learning and aphasia: Evidence from a paired associate and feedback-based task

    PubMed Central

    Vallila-Rohter, Sofia; Kiran, Swathi

    2013-01-01

    Though aphasia is primarily characterized by impairments in the comprehension and/or expression of language, research has shown that patients with aphasia also show deficits in cognitive-linguistic domains such as attention, executive function, concept knowledge and memory (Helm-Estabrooks, 2002 for review). Research in aphasia suggests that cognitive impairments can impact the online construction of language, new verbal learning, and transactional success (Freedman & Martin, 2001; Hula & McNeil, 2008; Ramsberger, 2005). In our research, we extend this hypothesis to suggest that general cognitive deficits influence progress with therapy. The aim of our study is to explore learning, a cognitive process that is integral to relearning language, yet underexplored in the field of aphasia rehabilitation. We examine non-linguistic category learning in patients with aphasia (n=19) and in healthy controls (n=12), comparing feedback and non-feedback based instruction. Participants complete two computer-based learning tasks that require them to categorize novel animals based on the percentage of features shared with one of two prototypes. As hypothesized, healthy controls showed successful category learning following both methods of instruction. In contrast, only 60% of our patient population demonstrated successful non-linguistic category learning. Patient performance was not predictable by standardized measures of cognitive ability. Results suggest that general learning is affected in aphasia and is a unique, important factor to consider in the field of aphasia rehabilitation. PMID:23127795

  9. Object-based task-level control: A hierarchical control architecture for remote operation of space robots

    NASA Technical Reports Server (NTRS)

    Stevens, H. D.; Miles, E. S.; Rock, S. J.; Cannon, R. H.

    1994-01-01

    Expanding man's presence in space requires capable, dexterous robots capable of being controlled from the Earth. Traditional 'hand-in-glove' control paradigms require the human operator to directly control virtually every aspect of the robot's operation. While the human provides excellent judgment and perception, human interaction is limited by low bandwidth, delayed communications. These delays make 'hand-in-glove' operation from Earth impractical. In order to alleviate many of the problems inherent to remote operation, Stanford University's Aerospace Robotics Laboratory (ARL) has developed the Object-Based Task-Level Control architecture. Object-Based Task-Level Control (OBTLC) removes the burden of teleoperation from the human operator and enables execution of tasks not possible with current techniques. OBTLC is a hierarchical approach to control where the human operator is able to specify high-level, object-related tasks through an intuitive graphical user interface. Infrequent task-level command replace constant joystick operations, eliminating communications bandwidth and time delay problems. The details of robot control and task execution are handled entirely by the robot and computer control system. The ARL has implemented the OBTLC architecture on a set of Free-Flying Space Robots. The capability of the OBTLC architecture has been demonstrated by controlling the ARL Free-Flying Space Robots from NASA Ames Research Center.

  10. Conceptual design of a lunar base solar power plant. Lunar base systems study task 3. 3

    SciTech Connect

    Not Available

    1988-08-01

    The best available concepts for a 100 kW Solar Lunar Power Plant based on static and dynamic conversion concepts have been examined. The two concepts which emerged for direct comparison yielded a difference in delivered mass of 35 MT, the mass equivalent of 1.4 lander payloads, in favor of the static concept. The technologies considered for the various elements are either state-of-the-art or near-term. Two photovoltaic cell concepts should receive high priority for development: i.e., amorphous silicon and indium phosphide cells. The amorphous silicon, because it can be made so light weight and rugged; and the indium phosphide, because it shows very high efficiency potential and is reportedly not degraded by radiation. Also the amorphous silicon cells may be mounted on flexible backing that may roll up much like a carpet for compact storage, delivery, and ease of deployment at the base. The fuel cell and electrolysis cell technology is quite well along for lunar base applications, and because both the Shuttle and the forthcoming Space Station incorporate these devices, the status quo will be maintained. Early development of emerging improvements should be implemented so that essential life verification test programs may commence.

  11. The Personality Trait of Intolerance to Uncertainty Affects Behavior in a Novel Computer-Based Conditioned Place Preference Task

    PubMed Central

    Radell, Milen L.; Myers, Catherine E.; Beck, Kevin D.; Moustafa, Ahmed A.; Allen, Michael Todd

    2016-01-01

    Recent work has found that personality factors that confer vulnerability to addiction can also affect learning and economic decision making. One personality trait which has been implicated in vulnerability to addiction is intolerance to uncertainty (IU), i.e., a preference for familiar over unknown (possibly better) options. In animals, the motivation to obtain drugs is often assessed through conditioned place preference (CPP), which compares preference for contexts where drug reward was previously received. It is an open question whether participants with high IU also show heightened preference for previously rewarded contexts. To address this question, we developed a novel computer-based CPP task for humans in which participants guide an avatar through a paradigm in which one room contains frequent reward (i.e., rich) and one contains less frequent reward (i.e., poor). Following exposure to both contexts, subjects are assessed for preference to enter the previously rich and previously poor room. Individuals with low IU showed little bias to enter the previously rich room first, and instead entered both rooms at about the same rate which may indicate a foraging behavior. By contrast, those with high IU showed a strong bias to enter the previously rich room first. This suggests an increased tendency to chase reward in the intolerant group, consistent with previously observed behavior in opioid-addicted individuals. Thus, the personality factor of high IU may produce a pre-existing cognitive bias that provides a mechanism to promote decision-making processes that increase vulnerability to addiction. PMID:27555829

  12. From PPP and CALL/MALL to a Praxis of Task-Based Teaching and Mobile Assisted Language Use

    ERIC Educational Resources Information Center

    Jarvis, Huw

    2015-01-01

    Two of the most significant trends in TESOL (Teachers of English to Speakers of Other Languages) over the last twenty years or so are the rise of task­-based language teaching (TBLT) and the growth of technology. With TBLT there is a challenging of more traditional structure-based models of delivery, and the increased capacity and mobility of…

  13. Using a Web-Based Course-Management System: An Evaluation of Management Tasks and Time Implications for the Instructor.

    ERIC Educational Resources Information Center

    Nijhuis, Gerard Gervedink; Collis, Betty

    2003-01-01

    Used data from a Web-based course management system in use at the Faculty of Educational Science and Technology, University of Twente, The Netherlands since 1998 to analyze tasks instructors must manage while using such a system. Results from 51 courses contribute to more efficient use of the Web-based course management system. (SLD)

  14. Metacognitive Awareness and the Fluency of Task-Based Oral Output across Planning Conditions: The Case of Iranian TEFL Students

    ERIC Educational Resources Information Center

    Seifoori, Zohreh

    2016-01-01

    The present inquiry inspected the impact of metacognitive awareness on the fluency of 114 Iranian TEFL learners' task-based oral output. The participants in six intact classes were selected from a population of 120 English sophomores based on their scores on proficiency pre-test. The classes were randomly assigned as two tripartite groups of…

  15. Comparison of Deck- and Trial-Based Approaches to Advantageous Decision Making on the Iowa Gambling Task

    ERIC Educational Resources Information Center

    Visagan, Ravindran; Xiang, Ally; Lamar, Melissa

    2012-01-01

    We compared the original deck-based model of advantageous decision making assessed with the Iowa Gambling Task (IGT) with a trial-based approach across behavioral and physiological outcomes in 33 younger adults (15 men, 18 women; 22.2 [plus or minus] 3.7 years of age). One administration of the IGT with simultaneous measurement of skin conductance…

  16. Sensorimotor feedback based on task-relevant error robustly predicts temporal recruitment and multidirectional tuning of muscle synergies

    PubMed Central

    Safavynia, Seyed A.

    2013-01-01

    We hypothesized that motor outputs are hierarchically organized such that descending temporal commands based on desired task-level goals flexibly recruit muscle synergies that specify the spatial patterns of muscle coordination that allow the task to be achieved. According to this hypothesis, it should be possible to predict the patterns of muscle synergy recruitment based on task-level goals. We demonstrated that the temporal recruitment of muscle synergies during standing balance control was robustly predicted across multiple perturbation directions based on delayed sensorimotor feedback of center of mass (CoM) kinematics (displacement, velocity, and acceleration). The modulation of a muscle synergy's recruitment amplitude across perturbation directions was predicted by the projection of CoM kinematic variables along the preferred tuning direction(s), generating cosine tuning functions. Moreover, these findings were robust in biphasic perturbations that initially imposed a perturbation in the sagittal plane and then, before sagittal balance was recovered, perturbed the body in multiple directions. Therefore, biphasic perturbations caused the initial state of the CoM to differ from the desired state, and muscle synergy recruitment was predicted based on the error between the actual and desired upright state of the CoM. These results demonstrate that that temporal motor commands to muscle synergies reflect task-relevant error as opposed to sensory inflow. The proposed hierarchical framework may represent a common principle of motor control across motor tasks and levels of the nervous system, allowing motor intentions to be transformed into motor actions. PMID:23100133

  17. Probabilistic estimation of residential air exchange rates for population-based human exposure modeling

    EPA Science Inventory

    Residential air exchange rates (AERs) are a key determinant in the infiltration of ambient air pollution indoors. Population-based human exposure models using probabilistic approaches to estimate personal exposure to air pollutants have relied on input distributions from AER meas...

  18. Using a physiologically based pharmacokinetic model to link urinary biomarker concentrations to dietary exposure of perchlorate

    EPA Science Inventory

    Exposure to perchlorate is widespread in the United States and many studies have attempted to character the perchlorate exposure by estimating the average daily intakes of perchlorate. These approaches provided population-based estimates, but did not provide individual-level exp...

  19. A Comparison of Exposure Control Procedures in CAT Systems Based on Different Measurement Models for Testlets

    ERIC Educational Resources Information Center

    Boyd, Aimee M.; Dodd, Barbara; Fitzpatrick, Steven

    2013-01-01

    This study compared several exposure control procedures for CAT systems based on the three-parameter logistic testlet response theory model (Wang, Bradlow, & Wainer, 2002) and Masters' (1982) partial credit model when applied to a pool consisting entirely of testlets. The exposure control procedures studied were the modified within 0.10 logits…

  20. Game-Based Approaches’ Pedagogical Principles: Exploring Task Constraints in Youth Soccer

    PubMed Central

    Serra-Olivares, Jaime; González-Víllora, Sixto; García-López, Luis Miguel; Araújo, Duarte

    2015-01-01

    This study tested the use of two pedagogical principles of Game-based approaches, representation and exaggeration, in the context of game performance of U10 soccer players. Twenty-one players participated in two 3 vs. 3 small-sided games. The first small-sided game was modified by representation. The second small-sided game was modified by enhancing the penetration of the defense tactical problem for invasion games. Decision-making and execution were assessed using the Game Performance Evaluation Tool. No significant differences were observed between games in the number of decision-making units related to keeping possession, nor in those related to penetrating the defense. No significant differences were observed in any execution ability (ball control, passing, dribbling and get free movements). The findings suggested that both games could provide similar degeneracy processes to the players for skill acquisition (specific and contextualized task constraints in which they could develop their game performance and the capability to achieve different outcomes in varying contexts). Probably both games had similar learner-environment dynamics leading players to develop their capabilities for adapting their behaviours to the changing performance situations. More research is necessary, from the ecological dynamics point of view, to determine how we should use small-sided games in Game-based approaches. PMID:26240668

  1. Game-Based Approaches' Pedagogical Principles: Exploring Task Constraints in Youth Soccer.

    PubMed

    Serra-Olivares, Jaime; González-Víllora, Sixto; García-López, Luis Miguel; Araújo, Duarte

    2015-06-27

    This study tested the use of two pedagogical principles of Game-based approaches, representation and exaggeration, in the context of game performance of U10 soccer players. Twenty-one players participated in two 3 vs. 3 small-sided games. The first small-sided game was modified by representation. The second small-sided game was modified by enhancing the penetration of the defense tactical problem for invasion games. Decision-making and execution were assessed using the Game Performance Evaluation Tool. No significant differences were observed between games in the number of decision-making units related to keeping possession, nor in those related to penetrating the defense. No significant differences were observed in any execution ability (ball control, passing, dribbling and get free movements). The findings suggested that both games could provide similar degeneracy processes to the players for skill acquisition (specific and contextualized task constraints in which they could develop their game performance and the capability to achieve different outcomes in varying contexts). Probably both games had similar learner-environment dynamics leading players to develop their capabilities for adapting their behaviours to the changing performance situations. More research is necessary, from the ecological dynamics point of view, to determine how we should use small-sided games in Game-based approaches.

  2. Task-based optimization of flip angle for texture analysis in MRI

    NASA Astrophysics Data System (ADS)

    Brand, Jonathan F.; Furenlid, Lars R.; Altbach, Maria I.; Galons, Jean-Phillippe; Bhattacharyya, Achyut; Sharma, Puneet; Bhattacharyya, Tulshi; Bilgin, Ali; Martin, Diego R.

    2016-03-01

    Chronic liver disease is a worldwide health problem, and hepatic fibrosis (HF) is one of the hallmarks of the disease. The current reference standard for diagnosing HF is biopsy followed by pathologist examination, however this is limited by sampling error and carries risk of complications. Pathology diagnosis of HF is based on textural change in the liver as a lobular collagen network that develops within portal triads. The scale of collagen lobules is characteristically on order of 1-5 mm, which approximates the resolution limit of in vivo gadolinium-enhanced magnetic resonance imaging in the delayed phase. We have shown that MRI of formalin fixed human ex vivo liver samples mimic the textural contrast of in vivo Gd-MRI and can be used as MRI phantoms. We have developed local texture analysis that is applied to phantom images, and the results are used to train model observers. The performance of the observer is assessed with the area-under-the-receiveroperator- characteristic curve (AUROC) as the figure of merit. To optimize the MRI pulse sequence, phantoms are scanned with multiple times at a range of flip angles. The flip angle that associated with the highest AUROC is chosen as optimal based on the task of detecting HF.

  3. Machine Learning Based Online Performance Prediction for Runtime Parallelization and Task Scheduling

    SciTech Connect

    Li, J; Ma, X; Singh, K; Schulz, M; de Supinski, B R; McKee, S A

    2008-10-09

    With the emerging many-core paradigm, parallel programming must extend beyond its traditional realm of scientific applications. Converting existing sequential applications as well as developing next-generation software requires assistance from hardware, compilers and runtime systems to exploit parallelism transparently within applications. These systems must decompose applications into tasks that can be executed in parallel and then schedule those tasks to minimize load imbalance. However, many systems lack a priori knowledge about the execution time of all tasks to perform effective load balancing with low scheduling overhead. In this paper, we approach this fundamental problem using machine learning techniques first to generate performance models for all tasks and then applying those models to perform automatic performance prediction across program executions. We also extend an existing scheduling algorithm to use generated task cost estimates for online task partitioning and scheduling. We implement the above techniques in the pR framework, which transparently parallelizes scripts in the popular R language, and evaluate their performance and overhead with both a real-world application and a large number of synthetic representative test scripts. Our experimental results show that our proposed approach significantly improves task partitioning and scheduling, with maximum improvements of 21.8%, 40.3% and 22.1% and average improvements of 15.9%, 16.9% and 4.2% for LMM (a real R application) and synthetic test cases with independent and dependent tasks, respectively.

  4. Task-Based Language Learning and Teaching: An Action-Research Study

    ERIC Educational Resources Information Center

    Calvert, Megan; Sheen, Younghee

    2015-01-01

    The creation, implementation, and evaluation of language learning tasks remain a challenge for many teachers, especially those with limited experience with using tasks in their teaching. This action-research study reports on one teacher's experience of developing, implementing, critically reflecting on, and modifying a language learning task…

  5. Lunar surface construction and assembly equipment study: Lunar Base Systems Study (LBSS) task 5.3

    NASA Technical Reports Server (NTRS)

    1988-01-01

    A set of construction and assembly tasks required on the lunar surface was developed, different concepts for equipment applicable to the tasks determined, and leading candidate systems identified for future conceptual design. Data on surface construction and assembly equipment systems are necessary to facilitate an integrated review of a complete lunar scenario.

  6. Evaluation of an Adaptive Automation Trigger Based on Task Performance, Priority, and Frequency

    DTIC Science & Technology

    2013-06-01

    the final trial, participants completed an additional post study questionnaire (Appendix A). Data Analysis SPSS 19 was employed to implement an...46 Data Analysis ................................................................................................................48 IV...each participant performed tasks during the trial, the data were subjected to near real-time analysis . Performance on five criterion task types was

  7. Learners' Perceptions of the Benefits of Voice Tool-Based Tasks on Their Spoken Performance

    ERIC Educational Resources Information Center

    Wilches, Astrid

    2014-01-01

    The purpose of this study is to investigate learners' perceptions of the benefits of tasks using voice tools to reinforce their oral skills. Additionally, this study seeks to determine what aspects of task design affected the students' perceptions. Beginner learners aged 18 to 36 with little or no experience in the use of technological tools for…

  8. Windowed correlation: a suitable tool for providing dynamic fMRI-based functional connectivity neurofeedback on task difficulty.

    PubMed

    Zilverstand, Anna; Sorger, Bettina; Zimmermann, Jan; Kaas, Amanda; Goebel, Rainer

    2014-01-01

    The goal of neurofeedback training is to provide participants with relevant information on their ongoing brain processes in order to enable them to change these processes in a meaningful way. Under the assumption of an intrinsic brain-behavior link, neurofeedback can be a tool to guide a participant towards a desired behavioral state, such as a healthier state in the case of patients. Current research in clinical neuroscience regarding the most robust indicators of pathological brain processes in psychiatric and neurological disorders indicates that fMRI-based functional connectivity measures may be among the most important biomarkers of disease. The present study therefore investigated the general potential of providing fMRI neurofeedback based on functional correlations, computed from short-window time course data at the level of single task periods. The ability to detect subtle changes in task performance with block-wise functional connectivity measures was evaluated based on imaging data from healthy participants performing a simple motor task, which was systematically varied along two task dimensions representing two different aspects of task difficulty. The results demonstrate that fMRI-based functional connectivity measures may provide a better indicator for an increase in overall (motor) task difficulty than activation level-based measures. Windowed functional correlations thus seem to provide relevant and unique information regarding ongoing brain processes, which is not captured equally well by standard activation level-based neurofeedback measures. Functional connectivity markers, therefore, may indeed provide a valuable tool to enhance and monitor learning within an fMRI neurofeedback setup.

  9. A computer-based interactive game to train persons with cognitive impairments to perform recycling tasks independently.

    PubMed

    Chang, Yao-Jen; Kang, Ya-Shu; Liu, Fang-Lin

    2014-12-01

    This study assessed the possibility of training three people with cognitive impairments using a computer-based interactive game. A game was designed to provide task prompts in recycling scenarios, identify incorrect task steps on the fly, and help users learn to make corrections. Based on a multiple baseline design, the data showed that the three participants considerably increased their target response, which improved their vocational job skills during the intervention phases and enabled them to maintain the acquired job skills after intervention. The practical and developmental implications of the results are discussed.

  10. Two Commentaries on Ron Sheen's "A Critical Analysis of the Advocacy of the Task-Based Syllabus." A Reader Reacts... [and] On the Advocacy of the Task-Based Syllabus [and] The Author Responds....

    ERIC Educational Resources Information Center

    Nunan, David; And Others

    1994-01-01

    An author, David Nunan, responds to a previous article that criticizes his advocacy of task-based syllabuses. Another author, Michael Long, points out inaccuracies in the criticism, and the author of the criticism, Ron Sheen, defends his earlier claim. (45 references) (JL)

  11. Task-driven optimization of CT tube current modulation and regularization in model-based iterative reconstruction.

    PubMed

    Gang, Grace Jianan; Siewerdsen, Jeffrey; Stayman, Joseph

    2017-03-31

    Tube current modulation (TCM) is routinely adopted on diagnostic CT scanners for dose reduction. Conventional TCM strategies are generally designed for filtered-backprojection (FBP) reconstruction to satisfy simple image quality requirements based on noise. This work investigates TCM designs for model-based iterative reconstruction (MBIR) to achieve optimal imaging performance as determined by a task-based image quality metric. Additionally, regularization is an important aspect of MBIR that is jointly optimized with TCM, and includes both the regularization strength that controls overall smoothness as well as directional weights that permits control of the isotropy/anisotropy of the local noise and resolution properties. Initial investigations focus on a known imaging task at a single location in the image volume. The framework adopts Fourier and analytical approximations for fast estimation of the local noise power spectrum (NPS) and modulation transfer function (MTF) - each carrying dependencies on TCM and regularization. For the single location optimization, the local detectability index (d') of the specific task was directly adopted as the objective function. A covariance matrix adaptation evolution strategy (CMA-ES) algorithm was employed to identify the optimal combination of imaging parameters. Evaluations of both conventional and task-driven approaches were performed in an abdomen phantom for a mid-frequency discrimination task in the kidney. Among the conventional strategies, the TCM pattern optimal for FBP using a minimum variance criterion yielded worse task-based performance compared to an unmodulated strategy when applied to MBIR. Moreover, task-driven TCM designs for MBIR were found to have the opposite behavior from conventional designs for FBP, with greater fluence assigned to the less attenuating views of the abdomen and less fluence to the more attenuating lateral views. Such TCM patterns exaggerate the intrinsic anisotropy of the MTF and NPS as

  12. Exposure to activity based anorexia impairs contextual learning in weight-restored rats without affecting spatial learning, taste, anxiety, or dietary-fat preference

    PubMed Central

    Boersma, Gretha J.; Treesukosol, Yada; Cordner, Zachary A.; Kastelein, Anneke; Choi, Pique; Moran, Timothy H.; Tamashiro, Kellie L.

    2016-01-01

    Relapse rates are high amongst cases of Anorexia Nervosa (AN) suggesting that some alterations induced by AN may remain after weight restoration. Objective To study the consequences of AN without confounds of environmental variability, a rodent model of activity based anorexia (ABA) can be employed. We hypothesized that exposure to ABA during adolescence may have long-term consequences in taste function, cognition, and anxiety-like behavior after weight restoration. Methods To test this hypothesis we exposed adolescent female rats to ABA (1.5 hrs food access, combined with voluntary running wheel access) and compared their behavior to that of control rats after weight restoration was achieved. The rats were tested for learning /memory, anxiety, food preference and taste in a set of behavioral tests performed during the light period. Results Our data show that ABA exposure leads to reduced performance during the novel object recognition task, a test for contextual learning, without altering performance in the novel place recognition task or the Barnes maze, both tasks that test spatial learning. Furthermore, we do not observe alterations in unconditioned lick responses to sucrose nor quinine (described by humans as “sweet” and “bitter” respectively). Nor did we find alterations in anxiety-like behavior during an elevated plus maze or an open field test. Finally, preference for a diet high in fat was not altered. Discussion Overall our data suggest that ABA exposure during adolescence impairs contextual learning in adulthood without altering spatial leaning, taste, anxiety, or fat preference. PMID:26711541

  13. Towards an effective cross-task mental workload recognition model using electroencephalography based on feature selection and support vector machine regression.

    PubMed

    Ke, Yufeng; Qi, Hongzhi; Zhang, Lixin; Chen, Shanguang; Jiao, Xuejun; Zhou, Peng; Zhao, Xin; Wan, Baikun; Ming, Dong

    2015-11-01

    Electroencephalographic (EEG) has been believed to be a potential psychophysiological measure of mental workload. There however remain a number of challenges in building a generalized mental workload recognition model, one of which includes the inability of an EEG-based workload classifier trained on a specific task to handle other tasks. The primary goal of the present study was to examine the possibility of addressing this challenge using feature selection and regression model. Support vector machine classifier and regression models were examined under within-task conditions (trained and tested on the same task) and cross-task conditions (trained on one task and tested on another task) for well-trained verbal and spatial n-back tasks. A specifically designed cross-task recursive feature elimination (RFE) based feature selection was used to handle the possible causes responsible for the deterioration of the performance of cross-task regression model. The within-task classification and regression performed fairly well. Cross-task classification and regression performance, however, deteriorated to unacceptable levels (around chance level). Trained and tested with the most robust feature subset selected by cross-task RFE, the performance of cross-task regression was significantly improved, and there were no significant changes in the performance of within-task regression. It can be inferred that workload-related features can be picked out from those which have been contaminated using RFE, and regression models rather than classifiers may be a wiser choice for cross-task conditions. These encouraging results suggest that the cross-task workload recognition model built in this study is much more generalizable across task when compared to the model built in traditional way.

  14. Noise properties and task-based evaluation of diffraction-enhanced imaging

    PubMed Central

    Brankov, Jovan G.; Saiz-Herranz, Alejandro; Wernick, Miles N.

    2014-01-01

    Abstract. Diffraction-enhanced imaging (DEI) is an emerging x-ray imaging method that simultaneously yields x-ray attenuation and refraction images and holds great promise for soft-tissue imaging. The DEI has been mainly studied using synchrotron sources, but efforts have been made to transition the technology to more practical implementations using conventional x-ray sources. The main technical challenge of this transition lies in the relatively lower x-ray flux obtained from conventional sources, leading to photon-limited data contaminated by Poisson noise. Several issues that must be understood in order to design and optimize DEI imaging systems with respect to noise performance are addressed. Specifically, we: (a) develop equations describing the noise properties of DEI images, (b) derive the conditions under which the DEI algorithm is statistically optimal, (c) characterize the imaging performance that can be obtained as measured by task-based metrics, and (d) consider image-processing steps that may be employed to mitigate noise effects. PMID:26158056

  15. Neural Bases of Unconscious Error Detection in a Chinese Anagram Solution Task: Evidence from ERP Study

    PubMed Central

    Yang, Junyi-; Li, Wei; Qiu, Jiang; Chen, Ying-yu

    2016-01-01

    In everyday life, error monitoring and processing are important for improving ongoing performance in response to a changing environment. However, detecting an error is not always a conscious process. The temporal activation patterns of brain areas related to cognitive control in the absence of conscious awareness of an error remain unknown. In the present study, event-related potentials (ERPs) in the brain were used to explore the neural bases of unconscious error detection when subjects solved a Chinese anagram task. Our ERP data showed that the unconscious error detection (UED) response elicited a more negative ERP component (N2) than did no error (NE) and detect error (DE) responses in the 300–400-ms time window, and the DE elicited a greater late positive component (LPC) than did the UED and NE in the 900–1200-ms time window after the onset of the anagram stimuli. Taken together with the results of dipole source analysis, the N2 (anterior cingulate cortex) might reflect unconscious/automatic conflict monitoring, and the LPC (superior/medial frontal gyrus) might reflect conscious error recognition. PMID:27149300

  16. Survey of RF exposure levels from mobile telephone base stations in Australia.

    PubMed

    Henderson, S I; Bangay, M J

    2006-01-01

    This paper reports the results of an exposure level survey of radiofrequency electromagnetic energy originating from mobile telephone base station antennas. Measurements of CDMA800, GSM900, GSM1800, and 3G(UMTS) signals were performed at distances ranging over 50 to 500 m from 60 base stations in five Australian cities. The exposure levels from these mobile telecommunications base stations were found to be well below the general public exposure limits of the ICNIRP guidelines and the Australian radiofrequency standard (ARPANSA RPS3). The highest recorded level from a single base station was 7.8 x 10(-3) W/m(2), which translates to 0.2% of the general public exposure limit.

  17. Antecedent Assessment and Assessment-Based Treatment of Off-Task Behavior in a Child Diagnosed with Attention Deficit-Hyperactivity Disorder (ADHD).

    ERIC Educational Resources Information Center

    Flood, William A.; Wilder, David A.

    2002-01-01

    Antecedent assessment and assessment-based intervention for off-task behavior by an 11-year-old with attention deficit hyperactivity disorder is reported. Assessment correlated off-task behavior with difficult academic tasks; intervention included functional communication training that focused on teaching the child to request assistance, as well…

  18. Exposure assessment of mobile phone base station radiation in an outdoor environment using sequential surrogate modeling.

    PubMed

    Aerts, Sam; Deschrijver, Dirk; Joseph, Wout; Verloock, Leen; Goeminne, Francis; Martens, Luc; Dhaene, Tom

    2013-05-01

    Human exposure to background radiofrequency electromagnetic fields (RF-EMF) has been increasing with the introduction of new technologies. There is a definite need for the quantification of RF-EMF exposure but a robust exposure assessment is not yet possible, mainly due to the lack of a fast and efficient measurement procedure. In this article, a new procedure is proposed for accurately mapping the exposure to base station radiation in an outdoor environment based on surrogate modeling and sequential design, an entirely new approach in the domain of dosimetry for human RF exposure. We tested our procedure in an urban area of about 0.04 km(2) for Global System for Mobile Communications (GSM) technology at 900 MHz (GSM900) using a personal exposimeter. Fifty measurement locations were sufficient to obtain a coarse street exposure map, locating regions of high and low exposure; 70 measurement locations were sufficient to characterize the electric field distribution in the area and build an accurate predictive interpolation model. Hence, accurate GSM900 downlink outdoor exposure maps (for use in, e.g., governmental risk communication and epidemiological studies) are developed by combining the proven efficiency of sequential design with the speed of exposimeter measurements and their ease of handling.

  19. Integrating English for Specific Purposes Courseware into Task-Based Learning in a Context of Preparing for International Trade Fairs

    ERIC Educational Resources Information Center

    Tsai, Shu-Chiao

    2013-01-01

    This study reports on integrating courseware for participating in international trade fairs into English for specific purposes (ESP) instruction at a technical university in Taiwan. An Information and Communication Technology (ICT) approach combining courseware integration with Task Based Learning (TBL), was adopted. Evaluation of implementing…

  20. Reflections on Speech Motor Control Based on Phonatory and DDK Tasks in Dysarthric Subjects with Lesions in Different Cerebellar Loci

    ERIC Educational Resources Information Center

    Vandana, V. P.

    2007-01-01

    There are very few acoustic studies reflecting on the localization of speech function within the different loci of the cerebellum. Task based performance profile of subjects with lesion in different cerebellar loci is not reported. Also, the findings on nonfocal cerebellar lesions cannot be generalized to lesions restricted to the cerebellum.…

  1. Implementing Task-Based Language Teaching to Integrate Language Skills in an EFL Program at a Colombian University

    ERIC Educational Resources Information Center

    Córdoba Zúñiga, Eulices

    2016-01-01

    This article reports the findings of a qualitative research study conducted with six first semester students of an English as a foreign language program in a public university in Colombia. The aim of the study was to implement task-based language teaching as a way to integrate language skills and help learners to improve their communicative…

  2. A colored petri nets based workload evaluation model and its validation through Multi-Attribute Task Battery-II.

    PubMed

    Wang, Peng; Fang, Weining; Guo, Beiyuan

    2017-04-01

    This paper proposed a colored petri nets based workload evaluation model. A formal interpretation of workload was firstly introduced based on the process that reflection of petri nets components to task. A petri net based description of Multiple Resources theory was given by comprehending it from a new angle. A new application of VACP rating scales named V/A-C-P unit, and the definition of colored transitions were proposed to build a model of task process. The calculation of workload mainly has the following four steps: determine token's initial position and values; calculate the weight of directed arcs on the basis of the rules proposed; calculate workload from different transitions, and correct the influence of repetitive behaviors. Verify experiments were carried out based on Multi-Attribute Task Battery-II software. Our results show that there is a strong correlation between the model values and NASA -Task Load Index scores (r=0.9513). In addition, this method can also distinguish behavior characteristics between different people.

  3. Active Tasks to Change the Use of Class Time within an Outcomes Based Approach to Curriculum Design

    ERIC Educational Resources Information Center

    Salter, Diane; Pang, Marco Y. C.; Sharma, Piyush

    2009-01-01

    This paper describes how new roles for instructors and learners can be integrated into course design and delivery by rethinking course design as part of a process-based staff development program. The goal of incorporating online learning tasks was to engage students with course resources prior to class time through active learning. The staff…

  4. The Role of Time on Task in Computer-Based Low-Stakes Assessment of Cross-Curricular Skills

    ERIC Educational Resources Information Center

    Kupiainen, Sirkku; Vainikainen, Mari-Pauliina; Marjanen, Jukka; Hautamäki, Jarkko

    2014-01-01

    The role of time on task (TOT) for students' attainment in a low-stakes assessment of cross-curricular skills was examined using the log data collected in the computer-based assessment (CBA). Two structural equation models were compared: Model 1, in which students' test scores were explained by grade point average (GPA) together with mastery and…

  5. Reading Guided by Automated Graphical Representations: How Model-Based Text Visualizations Facilitate Learning in Reading Comprehension Tasks

    ERIC Educational Resources Information Center

    Pirnay-Dummer, Pablo; Ifenthaler, Dirk

    2011-01-01

    Our study integrates automated natural language-oriented assessment and analysis methodologies into feasible reading comprehension tasks. With the newly developed T-MITOCAR toolset, prose text can be automatically converted into an association net which has similarities to a concept map. The "text to graph" feature of the software is based on…

  6. Approximating Implicit and Explicit Mentalizing with Two Naturalistic Video-Based Tasks in Typical Development and Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Rosenblau, Gabriela; Kliemann, Dorit; Heekeren, Hauke R.; Dziobek, Isabel

    2015-01-01

    Individuals with autism spectrum disorder (ASD) have been proposed to show greater impairments in implicit than explicit mentalizing. To test this proposition, we developed two comparable naturalistic tasks for a performance-based approximation of implicit and explicit mentalizing in 28 individuals with ASD and 23 matched typically developed (TD)…

  7. A learning scheme for reach to grasp movements: on EMG-based interfaces using task specific motion decoding models.

    PubMed

    Liarokapis, Minas V; Artemiadis, Panagiotis K; Kyriakopoulos, Kostas J; Manolakos, Elias S

    2013-09-01

    A learning scheme based on random forests is used to discriminate between different reach to grasp movements in 3-D space, based on the myoelectric activity of human muscles of the upper-arm and the forearm. Task specificity for motion decoding is introduced in two different levels: Subspace to move toward and object to be grasped. The discrimination between the different reach to grasp strategies is accomplished with machine learning techniques for classification. The classification decision is then used in order to trigger an EMG-based task-specific motion decoding model. Task specific models manage to outperform "general" models providing better estimation accuracy. Thus, the proposed scheme takes advantage of a framework incorporating both a classifier and a regressor that cooperate advantageously in order to split the task space. The proposed learning scheme can be easily used to a series of EMG-based interfaces that must operate in real time, providing data-driven capabilities for multiclass problems, that occur in everyday life complex environments.

  8. Thinking Together: Exploring Aspects of Shared Thinking between Young Children during a Computer-Based Literacy Task

    ERIC Educational Resources Information Center

    Wild, Mary

    2011-01-01

    This study considers in what ways sustained shared thinking between young children aged 5-6 years can be facilitated by working in dyads on a computer-based literacy task. The study considers 107 observational records of 44 children from 6 different schools, in Oxfordshire in the UK, collected over the course of a school year. The study raises…

  9. Improving 10th Graders' English Communicative Competence through the Implementation of the Task-Based Learning Approach

    ERIC Educational Resources Information Center

    Buitrago Campo, Ana Carolina

    2016-01-01

    This article reports the results of an action-research project focused on improving students' communicative competence in English through the task-based learning approach. This study was conducted in a co-educational public school in Medellín (Colombia) with thirty-four tenth graders. Actions implemented include the development of a series of…

  10. Focus-on-Form and EFL Learners' Language Development in Synchronous Computer-Mediated Communication: Task-Based Interactions

    ERIC Educational Resources Information Center

    Eslami, Zohreh R.; Kung, Wan-Tsai

    2016-01-01

    The purpose of this study was to explore the occurrence of incidental focus-on-form and its effect on subsequent second language (L2) production of learners of different dyads in an online task-based language learning context. The participants included Taiwanese learners of English as a foreign language at different proficiency levels, and native…

  11. Clarifying the role of target similarity, task relevance and feature-based suppression during sustained inattentional blindness.

    PubMed

    Drew, Trafton; Stohart, Cary

    2016-12-01

    How is feature-based attention distributed when engaged in a challenging attentional task? Thanks to formative electrophysiological and psychophysical work, we know a great deal about the spatial distribution of attention, but much less is known about how feature-based attention is allocated. In a large-scale online study, we investigated the distribution of attention to color space using a sustained inattentional blindness task. In order to query what parts of color space were being attended or inhibited, we varied the color of an unexpected stimulus on the final trial. Noticing rates for this stimulus indicate that when engaged in a difficult task that involves tracking items of one color and ignoring items of two different colors, observers attend the target color and inhibit the to-be ignored colors. Further, similarity to the target drives detection such that colors more similar to the target are more likely to be detected. Finally, our data suggest that when possible, observers inhibit regions of color space rather than individuating specific colors and adjusting the level of inhibition for a particular color accordingly. Together, our data support the notion of feature-based suppression for task relevant (to-be ignored) information, but we found no evidence of an inhibitory surround based on target color similarity.

  12. The Effect of Video-Based Tasks in Listening Comprehension of Iranian Pre-Intermediate EFL Learners

    ERIC Educational Resources Information Center

    Sarani, Abdullah; Behtash, Esmail Zare; Nezhad Arani, Saieed Moslemi

    2014-01-01

    This study aims at finding the effect of video-based tasks in improving the listening comprehension ability of Iranian pre-intermediate EFL (English Foreign Language) learners. After determining the level of learners, an experimental and control group, each of 20 participants, were nominated to contribute to the study. From the time the pre-test…

  13. Effects of Summary Writing on Oral Proficiency Performance within a Computer-Based Test for Integrated Listening-Speaking Tasks

    ERIC Educational Resources Information Center

    Lu, Zhihong; Wang, Yanfei

    2014-01-01

    The effective design of test items within a computer-based language test (CBLT) for developing English as a foreign language (EFL) learners' listening and speaking skills has become an increasingly challenging task for both test users and test designers compared with that of pencil-and-paper tests in the past. It needs to fit integrated oral…

  14. YouTube for Two: Online Video Resources in a Student-Centered, Task-Based ESL/EFL Environment

    ERIC Educational Resources Information Center

    Hamilton, Robert

    2010-01-01

    Online technology and streaming video have the potential to generate tremendous interest and motivation in ESL/EFL students. Unfortunately, as the basis for a task-based language teaching (TBLT) program, such technology often places students in a passive position and limits inter-student communication. This paper describes a successful TBLT course…

  15. Genre-Based Tasks in Foreign Language Writing: Developing Writers' Genre Awareness, Linguistic Knowledge, and Writing Competence

    ERIC Educational Resources Information Center

    Yasuda, Sachiko

    2011-01-01

    This study examines how novice foreign language (FL) writers develop their genre awareness, linguistic knowledge, and writing competence in a genre-based writing course that incorporates email-writing tasks. To define genre, the study draws on systemic functional linguistics (SFL) that sees language as a resource for making meaning in a particular…

  16. Virtual Task-Based Situated Language-Learning with "Second Life": Developing EFL Pragmatic Writing and Technological Self-Efficacy

    ERIC Educational Resources Information Center

    Abdallah, Mahmoud M. S.; Mansour, Marian M.

    2015-01-01

    This paper reports on an experimental research study that aimed at investigating the effectiveness of employing a virtual task-based situated language learning (TBSLL) environment mediated by Second Life (SL) in developing EFL student teachers' pragmatic writing skills and their technological self-efficacy. To reach this goal, a control-only…

  17. "Lo Cotidiano": The Effectiveness of Critical Task-Based Instruction in Teaching the Culture of Everyday Life

    ERIC Educational Resources Information Center

    García-Villada, Eduardo

    2014-01-01

    Teaching cultural competency in the language classroom can be a challenge. This study explores the effectiveness of task-based instruction (Lee, 2000) on the learning of culture by students in college-level Spanish language courses. Students were required to record oral presentations, write essays, and make comparisons between the culture and…

  18. Measuring cognitive load during simulation-based psychomotor skills training: sensitivity of secondary-task performance and subjective ratings.

    PubMed

    Haji, Faizal A; Khan, Rabia; Regehr, Glenn; Drake, James; de Ribaupierre, Sandrine; Dubrowski, Adam

    2015-12-01

    As interest in applying cognitive load theory (CLT) to the study and design of pedagogic and technological approaches in healthcare simulation grows, suitable measures of cognitive load (CL) are needed. Here, we report a two-phased study investigating the sensitivity of subjective ratings of mental effort (SRME) and secondary-task performance (signal detection rate, SDR and recognition reaction time, RRT) as measures of CL. In phase 1 of the study, novice learners and expert surgeons attempted a visual-monitoring task under two conditions: single-task (monitoring a virtual patient's heart-rate) and dual-task (tying surgical knots on a bench-top simulator while monitoring the virtual patient's heart-rate). Novices demonstrated higher mental effort and inferior secondary-task performance on the dual-task compared to experts (RRT 1.76 vs. 0.73, p = 0.012; SDR 0.27 vs. 0.97, p < 0.001; SRME 7.75 vs. 2.80, p < 0.001). Similarly, secondary task performance deteriorated from baseline to dual-task among novices (RRT 0.63 vs. 1.76 s, p < 0.006 and SDR 1.00 vs. 0.27, p < 0.001), but not experts (RRT 0.63 vs. 0.73 s, p = 0.124 and SDR 1.00 vs. 0.97, p = 0.178). In phase 2, novices practiced surgical knot-tying on the bench top simulator during consecutive dual-task trials. A significant increase in SDR (F(9,63) = 6.63, p < 0.001, f = 0.97) and decrease in SRME (F(9,63) = 9.39, p < 0.001, f = 1.04) was observed during simulation training, while RRT did not change significantly (F(9,63) = 1.18, p < 0.32, f = 0.41). The results suggest subjective ratings and dual-task performance can be used to track changes in CL among novices, particularly in early phases of simulation-based skills training. The implications for measuring CL in simulation instructional design research are discussed.

  19. The effects of type of interval, sensory modality, base duration, and psychophysical task on the discrimination of brief time intervals.

    PubMed

    Rammsayer, Thomas H

    2014-05-01

    The present study was designed to investigate the influences of type of psychophysical task (two-alternative forced-choice [2AFC] and reminder tasks), type of interval (filled vs. empty), sensory modality (auditory vs. visual), and base duration (ranging from 100 through 1,000 ms) on performance on duration discrimination. All of these factors were systematically varied in an experiment comprising 192 participants. This approach allowed for obtaining information not only on the general (main) effect of each factor alone, but also on the functional interplay and mutual interactions of some or all of these factors combined. Temporal sensitivity was markedly higher for auditory than for visual intervals, as well as for the reminder relative to the 2AFC task. With regard to base duration, discrimination performance deteriorated with decreasing base durations for intervals below 400 ms, whereas longer intervals were not affected. No indication emerged that overall performance on duration discrimination was influenced by the type of interval, and only two significant interactions were apparent: Base Duration × Type of Interval and Base Duration × Sensory Modality. With filled intervals, the deteriorating effect of base duration was limited to very brief base durations, not exceeding 100 ms, whereas with empty intervals, temporal discriminability was also affected for the 200-ms base duration. Similarly, the performance decrement observed with visual relative to auditory intervals increased with decreasing base durations. These findings suggest that type of task, sensory modality, and base duration represent largely independent sources of variance for performance on duration discrimination that can be accounted for by distinct nontemporal mechanisms.

  20. A Program Based on Task-Based Teaching Approach to Develop Creative Thinking Teaching Skills for Female Science Teachers in Kingdom of Saudi Arabia (KSA)

    ERIC Educational Resources Information Center

    Ibrahim, Manal Hassan Mohammed Bin

    2015-01-01

    This study aimed at developing creative thinking teaching skills for female science teachers in Kingdom of Saudi Arabia (KSA) through designing a program based on task-based teaching approach. The problem of the study was specified as the weakness of creative thinking teaching skills for science teachers in KSA and the need for programs based on…

  1. The Intersection of Task-Based Interaction, Task Complexity, and Working Memory: L2 Question Development through Recasts in a Laboratory Setting

    ERIC Educational Resources Information Center

    Kim, YouJin; Payant, Caroline; Pearson, Pamela

    2015-01-01

    The extent to which individual differences in cognitive abilities affect the relationship among task complexity, attention to form, and second language development has been addressed only minimally in the cognition hypothesis literature. The present study explores how reasoning demands in tasks and working memory (WM) capacity predict learners'…

  2. Implementation Approach for Plug-in Electric Vehicles at Joint Base Lewis McChord. Task 4

    SciTech Connect

    Schey, Stephen; Francfort, Jim

    2014-12-01

    This study focused on Joint Base Lewis McChord (JBLM), which is located in Washington State. Task 1 consisted of a survey of the non-tactical fleet of vehicles at JBLM to begin the review of vehicle mission assignments and the types of vehicles in service. In Task 2, daily operational characteristics of select vehicles were identified and vehicle movements were recorded in data loggers in order to characterize the vehicles’ missions. In Task 3, the results of the data analysis and observations were provided. Individual observations of the selected vehicles provided the basis for recommendations related to PEV adoption (i.e., whether a battery electric vehicle or plug-in hybrid electric vehicle [collectively referred to as PEVs] can fulfill the mission requirements0, as well as the basis for recommendations related to placement of PEV charging infrastructure. This report focuses on an implementation plan for the near-term adoption of PEVs into the JBLM fleet.

  3. Practising evidence-based medicine (EBM): a descriptive analysis of medical students' whole-task EBM assignments.

    PubMed

    Maggio, Lauren A; Capdarest-Arest, Nicole

    2017-04-01

    Researchers have suggested whole-task learning activities to practice and teach evidence-based medicine (EBM); however, limited description exists of their use in EBM curricula. This article describes medical students' execution of a whole-task EBM assignment and characterises themes emerging from assignment submissions. Between 2013 and 2015, Stanford University's paediatric clerkship students completed a whole-task EBM assignment based on a patient encounter. The assignment captured students' efforts to perform all EBM steps and describe their patient scenario and future knowledge needs strategies. Assignments were analysed using descriptive statistics and qualitative description. 123 students completed the assignment. Students formulated therapy (n=76), prognosis (n=18), diagnosis (n=15), harm (n=9) and aetiology (n=2) questions, and used a single (n=58) or multiple information resources (n=57). Based on evidence appraisal, 95 students indicated that the found evidence would inform future practice while 16 were sceptical of its conclusivity. 65 learners wanted to share evidence with colleagues; 33 with patients and families. To meet future knowledge needs, learners suggested using a structured approach (eg, PICO (patient, intervention, comparison and outcome); n=58), reading more primary literature (n=22) and creating question logs (n=21). This article provides a glimpse into students' EBM process and demonstrates the feasibility of whole-task activities for use in EBM training. Findings related to students' clinical uncertainty and information sharing raise questions about coverage of these topics in current EBM training and suggest that further investigation is warranted.

  4. Brain biomarkers based assessment of cognitive workload in pilots under various task demands.

    PubMed

    Gentili, Rodolphe J; Rietschel, Jeremy C; Jaquess, Kyle J; Lo, Li-Chuan; Prevost, Michael; Miller, Matt W; Mohler, Jessica M; Oh, Hyuk; Tan, Ying Ying; Hatfield, Bradley D

    2014-01-01

    Cognitive workload is an important element of cognitive-motor performance such as that exhibited during the piloting of an aircraft. Namely, an increase in task demands on the pilot can elevate cognitive information processing and, thus, the risk of human error. As such, there is a need to develop methods that reliably assess mental workload in pilots within operational settings. The present study contributes to this research goal by identifying physiological and brain biomarkers of cognitive workload and attentional reserve during a simulated aircraft piloting task under three progressive levels of challenge. A newly developed experimental method was employed by which electroencephalography (EEG) was acquired via a dry (i.e., gel-free sensors) system using few scalp sites. Self-reported responses to surveys and piloting performance indicators were analyzed. The findings revealed that as the challenge (task demands) increased, the perceived mental load increased, attentional reserve was attenuated, and task performance decreased. Such an increase in task demands was also reflected by changes in heart rate variability (HRV), as well as in the amplitude of the P300 component of event-related potentials to auditory probes, and in the spectral power of specific EEG frequency bands. This work provides a first step towards a long-term goal to develop a composite system of biomarkers for real-time cognitive workload assessment and state assessment of pilots in operational settings.

  5. Cooperative Scheduling of Imaging Observation Tasks for High-Altitude Airships Based on Propagation Algorithm

    PubMed Central

    Chuan, He; Dishan, Qiu; Jin, Liu

    2012-01-01

    The cooperative scheduling problem on high-altitude airships for imaging observation tasks is discussed. A constraint programming model is established by analyzing the main constraints, which takes the maximum task benefit and the minimum cruising distance as two optimization objectives. The cooperative scheduling problem of high-altitude airships is converted into a main problem and a subproblem by adopting hierarchy architecture. The solution to the main problem can construct the preliminary matching between tasks and observation resource in order to reduce the search space of the original problem. Furthermore, the solution to the sub-problem can detect the key nodes that each airship needs to fly through in sequence, so as to get the cruising path. Firstly, the task set is divided by using k-core neighborhood growth cluster algorithm (K-NGCA). Then, a novel swarm intelligence algorithm named propagation algorithm (PA) is combined with the key node search algorithm (KNSA) to optimize the cruising path of each airship and determine the execution time interval of each task. Meanwhile, this paper also provides the realization approach of the above algorithm and especially makes a detailed introduction on the encoding rules, search models, and propagation mechanism of the PA. Finally, the application results and comparison analysis show the proposed models and algorithms are effective and feasible. PMID:23365522

  6. Cooperative scheduling of imaging observation tasks for high-altitude airships based on propagation algorithm.

    PubMed

    Chuan, He; Dishan, Qiu; Jin, Liu

    2012-01-01

    The cooperative scheduling problem on high-altitude airships for imaging observation tasks is discussed. A constraint programming model is established by analyzing the main constraints, which takes the maximum task benefit and the minimum cruising distance as two optimization objectives. The cooperative scheduling problem of high-altitude airships is converted into a main problem and a subproblem by adopting hierarchy architecture. The solution to the main problem can construct the preliminary matching between tasks and observation resource in order to reduce the search space of the original problem. Furthermore, the solution to the sub-problem can detect the key nodes that each airship needs to fly through in sequence, so as to get the cruising path. Firstly, the task set is divided by using k-core neighborhood growth cluster algorithm (K-NGCA). Then, a novel swarm intelligence algorithm named propagation algorithm (PA) is combined with the key node search algorithm (KNSA) to optimize the cruising path of each airship and determine the execution time interval of each task. Meanwhile, this paper also provides the realization approach of the above algorithm and especially makes a detailed introduction on the encoding rules, search models, and propagation mechanism of the PA. Finally, the application results and comparison analysis show the proposed models and algorithms are effective and feasible.

  7. Public exposure to radio waves near GSM microcell and picocell base stations.

    PubMed

    Cooper, T G; Mann, S M; Khalid, M; Blackwell, R P

    2006-06-01

    Exposures of the general public to radio waves at locations near 20 randomly selected GSM microcell and picocell base stations in the UK have been assessed in the context of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. Compliance distances were calculated for the antennas of the base stations from their reported radiated powers. Under pessimistic assumptions that would maximise exposures, the minimum height at which the general public reference level could potentially be exceeded near any of the base station antennas was calculated to be 2.4 m above ground level. The power densities of the broadcast carriers transmitted by the base stations have been measured and scaled to include all other possible carriers. Exposures were generally in the range 0.002-2% of the ICNIRP general public reference level, and the greatest exposure quotient near any of the base stations was 8.6%. Exposures close to microcell base stations were found to be generally greater than those close to macrocell base stations.

  8. Korean Ministry of Environment's web-based visual consumer product exposure and risk assessment system (COPER).

    PubMed

    Lee, Hunjoo; Lee, Kiyoung; Park, Ji Young; Min, Sung-Gi

    2017-04-08

    With support from the Korean Ministry of the Environment (ME), our interdisciplinary research staff developed the COnsumer Product Exposure and Risk assessment system (COPER). This system includes various databases and features that enable the calculation of exposure and determination of risk caused by consumer products use. COPER is divided into three tiers: the integrated database layer (IDL), the domain specific service layer (DSSL), and the exposure and risk assessment layer (ERAL). IDL is organized by the form of the raw data (mostly non-aggregated data) and includes four sub-databases: a toxicity profile, an inventory of Korean consumer products, the weight fractions of chemical substances in the consumer products determined by chemical analysis and national representative exposure factors. DSSL provides web-based information services corresponding to each database within IDL. Finally, ERAL enables risk assessors to perform various exposure and risk assessments, including exposure scenario design via either inhalation or dermal contact by using or organizing each database in an intuitive manner. This paper outlines the overall architecture of the system and highlights some of the unique features of COPER based on visual and dynamic rendering engine for exposure assessment model on web.

  9. Feasibility of performing space surveillance tasks with a proposed space-based optical architecture

    NASA Astrophysics Data System (ADS)

    Flohrer, Tim; Krag, Holger; Klinkrad, Heiner; Schildknecht, Thomas

    Under ESA contract an industrial consortium including Aboa Space Research Oy (ASRO), the Astronomical Institute of the University of Bern (AIUB), and the Dutch National Aerospace Laboratory (NLR), proposed the observation concept, developed a suitable sensor architecture, and assessed the performance of a space-based optical (SBO) telescope in 2005. The goal of the SBO instrumentation was to analyse how the existing knowledge gap in the space debris population in the millimetre and centimetre regime may be closed by means of a passive op-tical instrument. SBO was requested to provide statistical information on the space debris population, in terms of number of objects and size distribution. The SBO was considered to be a cost-efficient instrumentation of 20 cm aperture and 6 deg field-of-view with flexible integration requirements. It should be possible to integrate the SBO easily as a secondary payload on satellites launched into low-Earth orbits (LEO), or into geostationary orbit (GEO). Thus the selected mission concept only allowed for fix-mounted telescopes, and the pointing direction could be requested freely. It was shown in the performance analysis that the statistical information on small-sized space debris can only be collected if the observation ranges are comparatively small. Two of the most promising concepts were to observe objects in LEO from a sensor placed into a sun-synchronous LEO, while objects in GEO should be observed from a GEO satellite. Since 2007 ESA focuses space surveillance and tracking activities in the Space Situational Awareness (SSA) preparatory program. Ground-based radars and optical telescopes are stud-ied for the build-up and to maintenance of a catalogue of objects. In this paper we analyse how the SBO architecture could contribute to the space surveillance tasks survey and tracking. We assume that the SBO instrumentation is placed into a circular sun-synchronous orbit at 800 km altitude. We discuss the observation conditions of

  10. fNIRS-based investigation of the Stroop task after TBI.

    PubMed

    Plenger, Patrick; Krishnan, Kamini; Cloud, Matthew; Bosworth, Chris; Qualls, Devin; Marquez de la Plata, Carlos

    2016-06-01

    To evaluate neural changes during a Stroop task among individuals with TBI using functional near-infrared spectroscopy (fNIRS). Thirteen healthy controls and 14 patients with moderate to severe TBI were included in this study. Oxygenated hemoglobin (HbO) was recorded every tenth of a second using a 52-channel fNIRS unit. Data were acquired using a block design during a Stroop task (i.e., Condition A = Dot Color Naming, Condition B = Incongruent Condition). Visual stimuli were presented on a computer monitor. Behaviorally, response accuracy was similar between groups for condition A, but the TBI group made more errors than the control group during condition B. During condition A, the patient group demonstrated significant increases in HbO within bilateral frontal regions compared to controls (p < 0.01). When examining the Stroop interference effect (B-A), controls showed increased HbO in bilateral frontal lobes and left inferior parietal region suggesting increased neural response to increased cognitive demand, whereas no differences were detected among the TBI group (p < 0.05). No between group differences in latency of HbO response was observed during either condition. While the TBI group performed as accurately as controls on the simpler dot color naming condition of the Stroop task, neural activity was greater within the frontal lobes during this relatively simple task among the TBI group suggesting neural inefficiency. Furthermore, the spatial distribution of neural activity related to the interference effect was not different among patients, suggesting the neural demand for the simpler task was comparable to that of the more cognitive demanding task among the TBI sample. The results suggest that fNIRS can identify frontal lobe inefficiency in TBI commonly observed with fMRI.

  11. Repeat Use of Post-exposure Prophylaxis for HIV Among Nairobi-Based Female Sex Workers Following Sexual Exposure.

    PubMed

    Izulla, Preston; McKinnon, Lyle R; Munyao, Julius; Ireri, Naomi; Nagelkerke, Nico; Gakii, Gloria; Gelmon, Lawrence; Nangami, Mabel; Kaul, Rupert; Kimani, Joshua

    2016-07-01

    As ART-based prevention becomes available, effectively targeting these interventions to key populations such as female sex workers (FSW) will be critical. In this study we analyze patterns of repeated post-exposure prophylaxis (PEP) access in the context of a large FSW program in Nairobi. During close to 6000 person-years of follow-up, 20 % of participants (n = 1119) requested PEP at least once and 3.7 % requested PEP more than once. Repeat PEP users were younger, had a higher casual partner volume, and were more likely to use condoms with casual and regular partners, have a regular partner, and test for HIV prior to enrolment. Barriers to PEP included stigma, side effects, and lack of knowledge, suggesting repeated promotion may be required for higher rates of uptake. A small subset of FSW, potentially those with heightened risk perception, showed a higher frequency of PEP use; these individuals may be most amenable to rollout of pre-exposure prophylaxis.

  12. Language mapping in children using resting-state functional connectivity: comparison with a task-based approach

    NASA Astrophysics Data System (ADS)

    Gallagher, Anne; Tremblay, Julie; Vannasing, Phetsamone

    2016-12-01

    Patients with brain tumor or refractory epilepsy may be candidates for neurosurgery. Presurgical evaluation often includes language investigation to prevent or reduce the risk of postsurgical language deficits. Current techniques involve significant limitations with pediatric populations. Recently, near-infrared spectroscopy (NIRS) has been shown to be a valuable neuroimaging technique for language localization in children. However, it typically requires the child to perform a task (task-based NIRS), which may constitute a significant limitation. Resting-state functional connectivity NIRS (fcNIRS) is an approach that can be used to identify language networks at rest. This study aims to assess the utility of fcNIRS in children by comparing fcNIRS to more conventional task-based NIRS for language mapping in 33 healthy participants: 25 children (ages 3 to 16) and 8 adults. Data were acquired at rest and during a language task. Results show very good concordance between both approaches for language localization (Dice similarity coefficient=0.81±0.13) and hemispheric language dominance (kappa=0.86, p<0.006). The fcNIRS technique may be a valuable tool for language mapping in clinical populations, including children and patients with cognitive and behavioral impairments.

  13. The perturbation paradigm modulates error-based learning in a highly automated task: outcomes in swallowing kinematics

    PubMed Central

    Anderson, C.; Macrae, P.; Taylor-Kamara, I.; Serel, S.; Vose, A.

    2015-01-01

    Traditional motor learning studies focus on highly goal-oriented, volitional tasks that often do not readily generalize to real-world movements. The goal of this study was to investigate how different perturbation paradigms alter error-based learning outcomes in a highly automated task. Swallowing was perturbed with neck surface electrical stimulation that opposes hyo-laryngeal elevation in 25 healthy adults (30 swallows: 10 preperturbation, 10 perturbation, and 10 postperturbation). The four study conditions were gradual-masked, gradual-unmasked, abrupt-masked, and abrupt-unmasked. Gradual perturbations increasingly intensified overtime, while abrupt perturbations were sustained at the same high intensity. The masked conditions reduced cues about the presence/absence of the perturbation (pre- and postperturbation periods had low stimulation), but unmasked conditions did not (pre- and postperturbation periods had no stimulation). Only hyo-laryngeal range of motion measures had significant outcomes; no timing measure demonstrated learning. Systematic-error reduction occurred only during the abrupt-masked and abrupt-unmasked perturbations. Only the abrupt-masked perturbation caused aftereffects. In this highly automated task, gradual perturbations did not induce learning similarly to findings of some volitional, goal-oriented adaptation task studies. Furthermore, our subtle and brief adjustment of the stimulation paradigm (masked vs. unmasked) determined whether aftereffects were present. This suggests that, in the unmasked group, sensory predictions of a motor plan were quickly and efficiently modified to disengage error-based learning behaviors. PMID:26023226

  14. Task-based evaluation of segmentation algorithms for diffusion-weighted MRI without using a gold standard.

    PubMed

    Jha, Abhinav K; Kupinski, Matthew A; Rodríguez, Jeffrey J; Stephen, Renu M; Stopeck, Alison T

    2012-07-07

    In many studies, the estimation of the apparent diffusion coefficient (ADC) of lesions in visceral organs in diffusion-weighted (DW) magnetic resonance images requires an accurate lesion-segmentation algorithm. To evaluate these lesion-segmentation algorithms, region-overlap measures are used currently. However, the end task from the DW images is accurate ADC estimation, and the region-overlap measures do not evaluate the segmentation algorithms on this task. Moreover, these measures rely on the existence of gold-standard segmentation of the lesion, which is typically unavailable. In this paper, we study the problem of task-based evaluation of segmentation algorithms in DW imaging in the absence of a gold standard. We first show that using manual segmentations instead of gold-standard segmentations for this task-based evaluation is unreliable. We then propose a method to compare the segmentation algorithms that does not require gold-standard or manual segmentation results. The no-gold-standard method estimates the bias and the variance of the error between the true ADC values and the ADC values estimated using the automated segmentation algorithm. The method can be used to rank the segmentation algorithms on the basis of both the ensemble mean square error and precision. We also propose consistency checks for this evaluation technique.

  15. Genocide Exposure and Subsequent Suicide Risk: A Population-Based Study

    PubMed Central

    Levine, Stephen Z.; Levav, Itzhak; Yoffe, Rinat; Becher, Yifat; Pugachova, Inna

    2016-01-01

    The association between periods of genocide-related exposures and suicide risk remains unknown. Our study tests that association using a national population-based study design. The source population comprised of all persons born during1922-1945 in Nazi-occupied or dominated European nations, that immigrated to Israel by 1965, were identified in the Population Register (N = 220,665), and followed up for suicide to 2014, totaling 16,953,602 person-years. The population was disaggregated to compare a trauma gradient among groups that immigrated before (indirect, n = 20,612, 9%); during (partial direct, n = 17,037, 8%); or after (full direct, n = 183,016, 83%) exposure to the Nazi era. Also, the direct exposure groups were examined regarding pre- or post-natal exposure periods. Cox regression models were used to compute Hazard Ratios (HR) of suicide risk to compare the exposure groups, adjusting for confounding by gender, residential SES and history of psychiatric hospitalization. In the total population, only the partial direct exposure subgroup was at greater risk compared to the indirect exposure group (HR = 1.73, 95% CI, 1.10, 2.73; P < .05). That effect replicated in six sensitivity analyses. In addition, sensitivity analyses showed that exposure at ages 13 plus among females, and follow-up by years since immigration were associated with a greater risk; whereas in utero exposure among persons with no psychiatric hospitalization and early postnatal exposure among males were at a reduced risk. Tentative mechanisms impute biopsychosocial vulnerability and natural selection during early critical periods among males, and feelings of guilt and entrapment or defeat among females. PMID:26901411

  16. Assessment of the dose reduction potential of a model-based iterative reconstruction algorithm using a task-based performance metrology

    SciTech Connect

    Samei, Ehsan; Richard, Samuel

    2015-01-15

    Purpose: Different computed tomography (CT) reconstruction techniques offer different image quality attributes of resolution and noise, challenging the ability to compare their dose reduction potential against each other. The purpose of this study was to evaluate and compare the task-based imaging performance of CT systems to enable the assessment of the dose performance of a model-based iterative reconstruction (MBIR) to that of an adaptive statistical iterative reconstruction (ASIR) and a filtered back projection (FBP) technique. Methods: The ACR CT phantom (model 464) was imaged across a wide range of mA setting on a 64-slice CT scanner (GE Discovery CT750 HD, Waukesha, WI). Based on previous work, the resolution was evaluated in terms of a task-based modulation transfer function (MTF) using a circular-edge technique and images from the contrast inserts located in the ACR phantom. Noise performance was assessed in terms of the noise-power spectrum (NPS) measured from the uniform section of the phantom. The task-based MTF and NPS were combined with a task function to yield a task-based estimate of imaging performance, the detectability index (d′). The detectability index was computed as a function of dose for two imaging tasks corresponding to the detection of a relatively small and a relatively large feature (1.5 and 25 mm, respectively). The performance of MBIR in terms of the d′ was compared with that of ASIR and FBP to assess its dose reduction potential. Results: Results indicated that MBIR exhibits a variability spatial resolution with respect to object contrast and noise while significantly reducing image noise. The NPS measurements for MBIR indicated a noise texture with a low-pass quality compared to the typical midpass noise found in FBP-based CT images. At comparable dose, the d′ for MBIR was higher than those of FBP and ASIR by at least 61% and 19% for the small feature and the large feature tasks, respectively. Compared to FBP and ASIR, MBIR

  17. Developing a job-exposure matrix with exposure uncertainty from expert elicitation and data modeling.

    PubMed

    Fischer, Heidi J; Vergara, Ximena P; Yost, Michael; Silva, Michael; Lombardi, David A; Kheifets, Leeka

    2017-01-01

    Job exposure matrices (JEMs) are tools used to classify exposures for job titles based on general job tasks in the absence of individual level data. However, exposure uncertainty due to variations in worker practices, job conditions, and the quality of data has never been quantified systematically in a JEM. We describe a methodology for creating a JEM which defines occupational exposures on a continuous scale and utilizes elicitation methods to quantify exposure uncertainty by assigning exposures probability distributions with parameters determined through expert involvement. Experts use their knowledge to develop mathematical models using related exposure surrogate data in the absence of available occupational level data and to adjust model output against other similar occupations. Formal expert elicitation methods provided a consistent, efficient process to incorporate expert judgment into a large, consensus-based JEM. A population-based electric shock JEM was created using these methods, allowing for transparent estimates of exposure.

  18. Learning Effects in the Block Design Task: A Stimulus Parameter-Based Approach

    ERIC Educational Resources Information Center

    Miller, Joseph C.; Ruthig, Joelle C.; Bradley, April R.; Wise, Richard A.; Pedersen, Heather A.; Ellison, Jo M.

    2009-01-01

    Learning effects were assessed for the block design (BD) task, on the basis of variation in 2 stimulus parameters: perceptual cohesiveness (PC) and set size uncertainty (U). Thirty-one nonclinical undergraduate students (19 female) each completed 3 designs for each of 4 varied sets of the stimulus parameters (high-PC/high-U, high-PC/low-U,…

  19. Text, Graphics, and Multimedia Materials Employed in Learning a Computer-Based Procedural Task

    ERIC Educational Resources Information Center

    Coffindaffer, Kari Christine Carlson

    2010-01-01

    The present research study investigated the interaction of graphic design students with different forms of software training materials. Four versions of the procedural task instructions were developed (A) Traditional Textbook with Still Images, (B) Modified Text with Integrated Still Images, (C) Onscreen Modified Text with Silent Onscreen Video…

  20. Nonoccurrence of Negotiation of Meaning in Task-Based Synchronous Computer-Mediated Communication

    ERIC Educational Resources Information Center

    Van Der Zwaard, Rose; Bannink, Anne

    2016-01-01

    This empirical study investigated the occurrence of meaning negotiation in an interactive synchronous computer-mediated second language (L2) environment. Sixteen dyads (N = 32) consisting of nonnative speakers (NNSs) and native speakers (NSs) of English performed 2 different tasks using videoconferencing and written chat. The data were coded and…

  1. A Task-Based Language Teaching Approach to Developing Metacognitive Strategies for Listening Comprehension

    ERIC Educational Resources Information Center

    Chou, Mu-Hsuan

    2017-01-01

    In second (L2) or foreign language (FL) learning, learning strategies help learners perform tasks, solve specific problems, and compensate for learning deficits. Of the strategy types, metacognitive strategies manage and regulate the construction of L2 or FL knowledge. Although learning strategies are frequently taught via teacher demonstration,…

  2. Temporal Effects of Alignment in Text-Based, Task-Oriented Discourse

    ERIC Educational Resources Information Center

    Foltz, Anouschka; Gaspers, Judith; Meyer, Carolin; Thiele, Kristina; Cimiano, Philipp; Stenneken, Prisca

    2015-01-01

    Communicative alignment refers to adaptation to one's communication partner. Temporal aspects of such alignment have been little explored. This article examines temporal aspects of lexical and syntactic alignment (i.e., tendencies to use the interlocutor's lexical items and syntactic structures) in task-oriented discourse. In particular, we…

  3. Performance-Based Task Assessment of Higher-Order Proficiencies in Redesigned STEM High Schools

    ERIC Educational Resources Information Center

    Ernst, Jeremy V.; Glennie, Elizabeth; Li, Songze

    2017-01-01

    This study explored student abilities in applying conceptual knowledge when presented with structured performance tasks. Specifically, the study gauged proficiency in higher-order applications of students enrolled in earth and environmental science or biology. The student sample was drawn from a Redesigned STEM high school model where a tested…

  4. Storyboarding: A Method for Bootstrapping the Design of Computer-Based Educational Tasks

    ERIC Educational Resources Information Center

    Jones, Ian

    2008-01-01

    There has been a recent call for the use of more systematic thought experiments when investigating learning. This paper presents a storyboarding method for capturing and sharing initial ideas and their evolution in the design of a mathematics learning task. The storyboards produced can be considered as "virtual data" created by thought experiments…

  5. Humans and Monkeys Exert Metacognitive Control Based on Learning Difficulty in a Perceptual Categorization Task

    ERIC Educational Resources Information Center

    Redford, Joshua S.

    2010-01-01

    Recently, Redford (2010) found that monkeys seemed to exert metacognitive control in a category-learning paradigm. Specifically, they selected more trials to view as the difficulty of the category-learning task increased. However, category-learning difficulty was determined by manipulating the family resemblance across the to-be-learned exemplars.…

  6. Developing Classroom Assessment Tasks Based on a Language Arts Curriculum: An In-service Approach.

    ERIC Educational Resources Information Center

    Patelis, Thanos; Singer, Judith

    The purpose of this study was twofold: to develop teachers' assessment skills and to enable teachers to apply this knowledge to the creation of assessment tasks for the language arts curriculum thereby linking curriculum to assessment. Using a newly developed language arts curriculum, 79 urban Connecticut teachers were asked to develop the…

  7. Classroom-Based Functional Analysis and Intervention for Disruptive and Off-Task Behaviors

    ERIC Educational Resources Information Center

    Shumate, Emily D.; Wills, Howard P.

    2010-01-01

    Although there is a growing body of literature on the use of functional analysis in schools, there is a need for more demonstrations of this technology being used during the course of typical instruction. In this study, we conducted functional analyses of disruptive and off-task behavior in a reading classroom setting for 3 participants of typical…

  8. Winning or Losing against an Opposite-Sex Peer on a Gender-Based Competitive Task.

    ERIC Educational Resources Information Center

    Gilbert, Stefanie; Thompson, J. Kevin

    1999-01-01

    Explored the effects on college students' mood and body image of a negative versus positive outcome in an opposite-sex, competitive peer interaction. Used one gender-neutral and one gender stereotypical task. There were no gender differences in reactions to winning or losing gender-neutral competitions, except marginally for depression. The…

  9. Designing Task-Based CALL To Promote Interaction: En busca de Esmeraldas.

    ERIC Educational Resources Information Center

    Gonzalez-Lloret, Marta

    2003-01-01

    Presents the necessary steps for designing an effective language learning tool to foster communication and negotiation, considering the importance of supporting integral education, using tasks, providing elaborated input and feedback, and promoting collaborative learning. Reports on a study conducted using such a tool to determine whether…

  10. Conflict tasks and the diffusion framework: Insight in model constraints based on psychological laws.

    PubMed

    Servant, Mathieu; Montagnini, Anna; Burle, Borís

    2014-07-01

    Formal models of decision-making have traditionally focused on simple, two-choice perceptual decisions. To date, one of the most influential account of this process is Ratcliff's drift diffusion model (DDM). However, the extension of the model to more complex decisions is not straightforward. In particular, conflicting situations, such as the Eriksen, Stroop, or Simon tasks, require control mechanisms that shield the cognitive system against distracting information. We adopted a novel strategy to constrain response time (RT) models by concurrently investigating two well-known empirical laws in conflict tasks, both at experimental and modeling levels. The two laws, predicted by the DDM, describe the relationship between mean RT and (i) target intensity (Piéron's law), (ii) standard deviation of RT (Wagenmakers-Brown's law). Pioneering work has shown that Piéron's law holds in the Stroop task, and has highlighted an additive relationship between target intensity and compatibility. We found similar results in both Eriksen and Simon tasks. Compatibility also violated Wagenmakers-Brown's law in a very similar and particular fashion in the two tasks, suggesting a common model framework. To investigate the nature of this commonality, predictions of two recent extensions of the DDM that incorporate selective attention mechanisms were simulated and compared to the experimental results. Both models predict Piéron's law and the violation of Wagenmakers-Brown's law by compatibility. Fits of the models to the RT distributions and accuracy data allowed us to further reveal their relative strengths and deficiencies. Combining experimental and computational results, this study sets the groundwork for a unified model of decision-making in conflicting environments.

  11. Calculation of lifetime lung cancer risks associated with radon exposure, based on various models and exposure scenarios.

    PubMed

    Hunter, Nezahat; Muirhead, Colin R; Bochicchio, Francesco; Haylock, Richard G E

    2015-09-01

    The risk of lung cancer mortality up to 75 years of age due to radon exposure has been estimated for both male and female continuing, ex- and never-smokers, based on various radon risk models and exposure scenarios. We used risk models derived from (i) the BEIR VI analysis of cohorts of radon-exposed miners, (ii) cohort and nested case-control analyses of a European cohort of uranium miners and (iii) the joint analysis of European residential radon case-control studies. Estimates of the lifetime lung cancer risk due to radon varied between these models by just over a factor of 2 and risk estimates based on models from analyses of European uranium miners exposed at comparatively low rates and of people exposed to radon in homes were broadly compatible. For a given smoking category, there was not much difference in lifetime lung cancer risk between males and females. The estimated lifetime risk of radon-induced lung cancer for exposure to a concentration of 200 Bq m(-3) was in the range 2.98-6.55% for male continuing smokers and 0.19-0.42% for male never-smokers, depending on the model used and assuming a multiplicative relationship for the joint effect of radon and smoking. Stopping smoking at age 50 years decreases the lifetime risk due to radon by around a half relative to continuing smoking, but the risk for ex-smokers remains about a factor of 5-7 higher than that for never-smokers. Under a sub-multiplicative model for the joint effect of radon and smoking, the lifetime risk of radon-induced lung cancer was still estimated to be substantially higher for continuing smokers than for never smokers. Radon mitigation-used to reduce radon concentrations at homes-can also have a substantial impact on lung cancer risk, even for persons in their 50 s; for each of continuing smokers, ex-smokers and never-smokers, radon mitigation at age 50 would lower the lifetime risk of radon-induced lung cancer by about one-third. To maximise risk reductions, smokers in high

  12. Studying permethrin exposure in flight attendants using a physiologically based pharmacokinetic model.

    PubMed

    Wei, Binnian; Isukapalli, Sastry S; Weisel, Clifford P

    2013-07-01

    Assessment of potential health risks to flight attendants from exposure to pyrethroid insecticides, used for aircraft disinsection, is limited because of (a) lack of information on exposures to these insecticides, and (b) lack of tools for linking these exposures to biomarker data. We developed and evaluated a physiologically based pharmacokinetic (PBPK) model to assess the exposure of flight attendants to the pyrethroid insecticide permethrin attributable to aircraft disinsection. The permethrin PBPK model was developed by adapting previous models for pyrethroids, and was parameterized using currently available metabolic parameters for permethrin. The human permethrin model was first evaluated with data from published human studies. Then, it was used to estimate urinary metabolite concentrations of permethrin in flight attendants who worked in aircrafts, which underwent residual and pre-flight spray treatments. The human model was also applied to analyze the toxicokinetics following permethrin exposures attributable to other aircraft disinsection scenarios. Predicted levels of urinary 3-phenoxybenzoic acid (3-PBA), a metabolite of permethrin, following residual disinsection treatment were comparable to the measurements made for flight attendants. Simulations showed that the median contributions of the dermal, oral and inhalation routes to permethrin exposure in flight attendants were 83.5%, 16.1% and 0.4% under residual treatment scenario, respectively, and were 5.3%, 5.0% and 89.7% under pre-flight spray scenario, respectively. The PBPK model provides the capability to simulate the toxicokinetic profiles of permethrin, and can be used in the studies on human exposure to permethrin.

  13. Comparative international analysis of radiofrequency exposure surveys of mobile communication radio base stations.

    PubMed

    Rowley, Jack T; Joyner, Ken H

    2012-01-01

    This paper presents analyses of data from surveys of radio base stations in 23 countries across five continents from the year 2000 onward and includes over 173,000 individual data points. The research compared the results of the national surveys, investigated chronological trends and compared exposures by technology. The key findings from this data are that irrespective of country, the year and cellular technology, exposures to radio signals at ground level were only a small fraction of the relevant human exposure standards. Importantly, there has been no significant increase in exposure levels since the widespread introduction of 3G mobile services, which should be reassuring for policy makers and negate the need for post-installation measurements at ground level for compliance purposes. There may be areas close to antennas where compliance levels could be exceeded. Future potential work includes extending the study to additional countries, development of cumulative exposure distributions and investigating the possibility of linking exposure measurements to population statistics to assess the distribution of exposure levels relative to population percentiles.

  14. Comparative international analysis of radiofrequency exposure surveys of mobile communication radio base stations

    PubMed Central

    Rowley, Jack T; Joyner, Ken H

    2012-01-01

    This paper presents analyses of data from surveys of radio base stations in 23 countries across five continents from the year 2000 onward and includes over 173,000 individual data points. The research compared the results of the national surveys, investigated chronological trends and compared exposures by technology. The key findings from this data are that irrespective of country, the year and cellular technology, exposures to radio signals at ground level were only a small fraction of the relevant human exposure standards. Importantly, there has been no significant increase in exposure levels since the widespread introduction of 3G mobile services, which should be reassuring for policy makers and negate the need for post-installation measurements at ground level for compliance purposes. There may be areas close to antennas where compliance levels could be exceeded. Future potential work includes extending the study to additional countries, development of cumulative exposure distributions and investigating the possibility of linking exposure measurements to population statistics to assess the distribution of exposure levels relative to population percentiles. PMID:22377680

  15. "Development of Model-Based Air Pollution Exposure Metrics for use in Epidemiologic Studies"

    EPA Science Inventory

    Population-based epidemiological studies of air pollution have traditionally relied upon imperfect surrogates of personal exposures, such as area-wide ambient air pollution levels based on readily available concentrations from central monitoring sites. U.S. EPA in collaboration w...

  16. DEVELOPMENT OF MODEL-BASED AIR POLLUTION EXPOSURE METRICS FOR USE IN EPIDEMIOLOGIC STUDIES

    EPA Science Inventory

    Population-based epidemiological studies of air pollution have traditionally relied upon imperfect surrogates of personal exposures, such as area-wide ambient air pollution levels based on readily available concentrations from central monitoring sites. U.S. EPA in collaboration w...

  17. A Community-Based Initiative to Reduce Children's Exposure to Toxics in Household Products

    ERIC Educational Resources Information Center

    Blackman, Anne Berlin; Luskin, Jack

    2006-01-01

    Purpose--The purpose of this paper is to explore the efficacy of a community-based outreach initiative, piloted in Worcester, Massachusetts, to reduce children's exposure to toxic chemicals in common household products by changing parental behavior regarding product purchase and use. Design/methodology/approach--The program model was based on the…

  18. The effect of additional exposure to the unique features in a perceptual learning task can be attributed to a location bias.

    PubMed

    Recio, Sergio A; Iliescu, Adela F; Bergés, Germán D; Gil, Marta; de Brugada, Isabel

    2016-04-01

    It has been suggested that human perceptual learning could be explained in terms of a better memory encoding of the unique features during intermixed exposure. However, it is possible that a location bias could play a relevant role in explaining previous results of perceptual learning studies using complex visual stimuli. If this were the case, the only relevant feature would be the location, rather than the content, of the unique features. To further explore this possibility, we attempted to replicate the results of Lavis, Kadib, Mitchell, and Hall (2011, Experiment 2), which showed that additional exposure to the unique elements resulted in better discrimination than simple intermixed exposure. We manipulated the location of the unique elements during the additional exposure. In one experiment, they were located in the same position as that when presented together with the common element. In another experiment, the unique elements were located in the center of the screen, regardless of where they were located together with the common element. Our results showed that additional exposure only improved discrimination when the unique elements were presented in the same position as when they were presented together with the common element. The results reported here do not provide support for the explanation of the effects of additional exposure of the unique elements in terms of a better memory encoding and instead suggest an explanation in terms of location bias.

  19. Assessment of Charging Infrastructure for Plug-in Electric Vehicles at Marine Corps Base Camp Lejeune. Task 3

    SciTech Connect

    Schey, Stephen; Francfort, Jim

    2015-11-01

    Battelle Energy Alliance, LLC, managing and operating contractor for the U.S. Department of Energy’s Idaho National Laboratory, is the lead laboratory for the U.S. Department of Energy’s advanced vehicle testing. Battelle Energy Alliance, LLC contracted with Intertek Testing Services, North America (Intertek) to conduct several U.S. Department of Defense-based studies to identify potential U.S. Department of Defense transportation systems that are strong candidates for introduction or expansion of plug-in electric vehicles (PEVs). Task 1 consisted of a survey of the non-tactical fleet of vehicles at Marine Corps Base Camp Lejeune to begin the review of vehicle mission assignments and types of vehicles in service. Task 2 selected vehicles for further monitoring and involved identifying daily operational characteristics of these select vehicles. Data logging of vehicle movements was initiated in order to characterize the vehicle’s mission. The Task 3 vehicle utilization report provided results of the data analysis and observations related to the replacement of current vehicles with PEVs. Finally, this report provides an assessment of charging infrastructure required to support the suggested PEV replacements. Intertek acknowledges the support of Idaho National Laboratory, Marine Corps headquarters, and Marine Corps Base Camp Lejeune Fleet management and personnel for participation in this study. Intertek is pleased to provide this report and is encouraged by enthusiasm and support from Marine Corps Base Camp Lejeune personnel.

  20. Towards a cognitive robotics methodology for reward-based decision-making: dynamical systems modelling of the Iowa Gambling Task

    NASA Astrophysics Data System (ADS)

    Lowe, Robert; Ziemke, Tom

    2010-09-01

    The somatic marker hypothesis (SMH) posits that the role of emotions and mental states in decision-making manifests through bodily responses to stimuli of import to the organism's welfare. The Iowa Gambling Task (IGT), proposed by Bechara and Damasio in the mid-1990s, has provided the major source of empirical validation to the role of somatic markers in the service of flexible and cost-effective decision-making in humans. In recent years the IGT has been the subject of much criticism concerning: (1) whether measures of somatic markers reveal that they are important for decision-making as opposed to behaviour preparation; (2) the underlying neural substrate posited as critical to decision-making of the type relevant to the task; and (3) aspects of the methodological approach used, particularly on the canonical version of the task. In this paper, a cognitive robotics methodology is proposed to explore a dynamical systems approach as it applies to the neural computation of reward-based learning and issues concerning embodiment. This approach is particularly relevant in light of a strongly emerging alternative hypothesis to the SMH, the reversal learning hypothesis, which links, behaviourally and neurocomputationally, a number of more or less complex reward-based decision-making tasks, including the 'A-not-B' task - already subject to dynamical systems investigations with a focus on neural activation dynamics. It is also suggested that the cognitive robotics methodology may be used to extend systematically the IGT benchmark to more naturalised, but nevertheless controlled, settings that might better explore the extent to which the SMH, and somatic states per se, impact on complex decision-making.

  1. Occupational exposure limits for 30 organophosphate pesticides based on inhibition of red blood cell acetylcholinesterase.

    PubMed

    Storm, J E; Rozman, K K; Doull, J

    2000-09-07

    Toxicity and other relevant data for 30 organophosphate pesticides were evaluated to suggest inhalation occupational exposure limits (OELs), and to support development of a risk assessment strategy for organophosphates in general. Specifically, the value of relative potency analysis and the predictability of inhalation OELs by acute toxicity measures and by repeated oral exposure NOELs was assessed. Suggested OELs are based on the prevention of red blood cell (RBC) acetylcholinesterase (AChE) inhibition and are derived using a weight-of-evidence risk assessment approach. Suggested OEL values range from 0.002 to 2 mg/m(3), and in most cases, are less than current permissible exposure levels (PELs) or threshold limit values(R) (TLVs(R)). The available data indicate that experimental data for most organophosphates evaluated are limited; most organophosphates are equally potent RBC AChE inhibitors in different mammalian species; NOELs from repeated exposure studies of variable duration are usually equivalent; and, no particular grouping based on organophosphate structure is consistently more potent than another. Further, relative potency analyses have limited usefulness in the risk assessment of organophosphates. The data also indicated that equivalent relative potency relationships do not exist across either exposure duration (acute vs. repeated) or exposure route (oral vs. inhalation). Consideration of all variable duration and exposure route studies are therefore usually desirable in the development of an OEL, especially when data are limited. Also, neither acute measures of toxicity nor repeated oral exposure NOELs are predictive of weight-of-evidence based inhalation OELs. These deviations from what is expected based on the common mechanism of action for organophosphates across exposure duration and route - AChE inhibition - is likely due to the lack of synchrony between the timing of target tissue effective dose and the experimental observation of equivalent

  2. Impact of Hospital-Based Environmental Exposures on Neurodevelopmental Outcomes of Preterm Infants

    PubMed Central

    Santos, Janelle; Pearce, Sarah E.; Stroustrup, Annemarie

    2015-01-01

    Purpose of review Over 300,000 infants are hospitalized in a neonatal intensive care unit (NICU) in the United States annually during a developmental period critical to later neurobehavioral function. Environmental exposures during the fetal period and infancy have been shown to impact long-term neurobehavioral outcomes. This review summarizes evidence linking NICU-based environmental exposures to neurodevelopmental outcomes of children born preterm, Recent findings Preterm infants experience multiple exposures important to neurodevelopment during the NICU hospitalization. The physical layout of the NICU, management of light and sound, social interactions with parents and NICU staff, and chemical exposures via medical equipment are important to long-term neurobehavioral outcomes in this highly vulnerable population. Summary Existing research documents NICU-based exposure to 1) neurotoxic chemicals, 2) aberrant light, 3) excess sound, and 4) restricted social interaction. In total, this creates an environment of co-existing excesses (chemicals, light, sound) and deprivation (touch, speech). The full impact of these co-exposures on the long-term neurodevelopment of preterm infants has not been adequately elucidated. Research into the importance of the NICU from an environmental health perspective is in its infancy, but could provide understanding about critical modifiable factors impacting the neurobehavioral health of hundreds of thousands of children each year. PMID:25635585

  3. An industrial radiography exposure device based on measurement of transmitted gamma-ray intensity

    NASA Astrophysics Data System (ADS)

    Polee, C.; Chankow, N.; Srisatit, S.; Thong-Aram, D.

    2015-05-01

    In film radiography, underexposure and overexposure may happen particularly when lacking information of specimen material and hollowness. This paper describes a method and a device for determining exposure in industrial gamma-ray radiography based on quick measurement of transmitted gamma-ray intensity with a small detector. Application software was developed for Android mobile phone to remotely control the device and to display counting data via Bluetooth communication. Prior to film exposure, the device is placed behind a specimen to measure transmitted intensity which is inversely proportional to the exposure. Unlike in using the conventional exposure curve, correction factors for source decay, source-to- film distance, specimen thickness and kind of material are not needed. The developed technique and device make radiographic process economic, convenient and more reliable.

  4. Exposure-Based Cognitive Behavior Therapy for Children with Abdominal Pain: A Pilot Trial

    PubMed Central

    Olén, Ola; Bonnert, Marianne; Hedman, Erik; Serlachius, Eva; Ljótsson, Brjánn

    2016-01-01

    Background Children with pain-related functional gastrointestinal disorders (P-FGIDs) have an increased risk for school absenteeism, depression, anxiety and low quality of life. Exposure-based cognitive behavior therapy (CBT) has shown large treatment effects in adults with irritable bowel syndrome, but has not been tested for children 8–12 years with P-FGIDs. Aim The aim of this trial was to test the feasibility, acceptability and potential efficacy of a newly developed exposure-based CBT for children with P-FGIDs. Method The children (n = 20) with a P-FGID, were referred by their treating physicians. The participants received 10 weekly sessions of exposure-based CBT and were assessed at pre-treatment, post-treatment and 6-month follow-up. Results Children improved significantly on the primary outcome measure pain intensity at post (Cohen’s d = 0.40, p = 0.049) and at 6-month follow-up (Cohen’s d = 0.85, p = 0.004). Improvements were also seen in pain frequency, gastrointestinal symptoms, quality of life, depression, anxiety, school absenteeism and somatic symptoms. Improvements were maintained or further increased at 6-month follow-up. The children engaged in the exposures and were satisfied with the treatment. Conclusions Exposure-based CBT for children with P-FGIDs is feasible, acceptable and potentially efficacious. PMID:27736943

  5. Response of Inconel 617 superalloy to combined ground-based and STS reentry exposure

    NASA Technical Reports Server (NTRS)

    Clark, R. K.; Unnam, J.

    1984-01-01

    Inconel 617 is a nickel-based superalloy which is being considered for heat-shield applications because of its high-temperature strength, good oxidation resistance and high emittance of oxidized surfaces. While the effects of simulated reentry conditions on emittance and oxidation of Inconel 617 have been studied, the combined effects of the ground-based environment with sea salt exposure and the reentry environment have not been evaluated. Experimental results are presented to show the effects of environmental simulation including ground-based and reentry exposure on the emittance and oxidation of Inconel 617. Specimens were exposed to simulated reentry at a surface temperature of 2000 F in the Langley Research Center Hypersonic Materials Environmental Test System (HYMETS) Facility with and without alternate exposures to an atmospheric seashore environment or a laboratory sea salt environment. This paper presents emittance, mass loss, oxide chemistry, and alloy composition data for the specimens.

  6. Study of behavioural and neural bases of visuo-spatial working memory with an fMRI paradigm based on an n-back task.

    PubMed

    Dores, Artemisa R; Barbosa, Fernando; Carvalho, Irene P; Almeida, Isabel; Guerreiro, Sandra; da Rocha, Benedita M; de Sousa, Liliana; Castro-Caldas, Alexandre

    2017-03-01

    The goal of this study was to propose a new functional magnetic resonance imaging (fMRI) paradigm using a language-free adaptation of a 2-back working memory task to avoid cultural and educational bias. We additionally provide an index of the validity of the proposed paradigm and test whether the experimental task discriminates the behavioural performances of healthy participants from those of individuals with working memory deficits. Ten healthy participants and nine patients presenting working memory (WM) deficits due to acquired brain injury (ABI) performed the developed task. To inspect whether the paradigm activates brain areas typically involved in visual working memory (VWM), brain activation of the healthy participants was assessed with fMRIs. To examine the task's capacity to discriminate behavioural data, performances of the healthy participants in the task were compared with those of ABI patients. Data were analysed with GLM-based random effects procedures and t-tests. We found an increase of the BOLD signal in the specialized areas of VWM. Concerning behavioural performances, healthy participants showed the predicted pattern of more hits, less omissions and a tendency for fewer false alarms, more self-corrected responses, and faster reaction times, when compared with subjects presenting WM impairments. The results suggest that this task activates brain areas involved in VWM and discriminates behavioural performances of clinical and non-clinical groups. It can thus be used as a research methodology for behavioural and neuroimaging studies of VWM in block-design paradigms.

  7. The association between health anxiety and disgust reactions in a contamination-based behavioral approach task.

    PubMed

    Goetz, Amy R; Lee, Han-Joo; Cougle, Jesse R

    2013-01-01

    Existing evidence suggests that disgust is an important affective process related to health anxiety. The present study sought to determine the contribution of health anxiety symptoms in the prediction of disgust and behavioral avoidance in a large, nonclinical sample (N=156). Regression analyses showed that overall health anxiety symptoms predicted disgust on a behavioral approach task independent of gender, negative affect, and fear of contamination. Particularly, health anxiety-related reassurance seeking was found to be uniquely associated with disgust and behavioral avoidance after controlling for the aforementioned covariates. In addition, the interaction between health anxiety and contamination fear was tested, and remained significant when controlling for gender and negative affect. These results suggest that heightened contamination fear is associated with elevated disgust reactions such that high levels of health anxiety leads even those low in contamination fear to be disgusted during a behavioral task. These results are in line with previous research on the role of disgust in health anxiety.

  8. Task Force on Energy Systems for Forward/Remote Operating Bases

    DTIC Science & Technology

    2016-08-01

    deployable, cost-effective, regulated, and secure small modular reactors with a modest output of electrical power (less than 10 megawatts) to improve ...addressing energy demands and alternatives to improve energy effectiveness of our troops. The Task Force concluded that there is an opportunity for...combat capability and improve deployed conditions for the Department of Defense. Furthermore, under the Terms of Reference, it was stipulated the

  9. Human Performance Task Batteries and Models: An Abilities-Based Directory

    DTIC Science & Technology

    1986-12-01

    Valerie McClain whose considerable efforts helped bring together the many divergent elements of this work, and to Dr. Eduardo Salas of the Naval...acoustic confusabil’y of certaTn^ . S’.; °o ^ ^^^enteen of the twenty-six letters of the alphabet are used in the task ^ m ?in n...a programmable timer module (California Computer Systems 7440 A). The IBM compatible version requires a 64K Corona portable computer with internal

  10. Exploring the Structure and Task Dynamics of Terrorist Organizations Using Agent Based Modeling

    DTIC Science & Technology

    2008-12-01

    such as the electric power grid) and biological (such as DNA ) (Newman, 2003). In order to understand terrorist networks, many analysts use the...such as the electric power grid) and biological networks (such as DNA ) (Newman, 2003). Network theory suggests three main categories of networks...e.g., as Machine Bureaucracy or Adhocracy (Mintzberg, 1980)) and the sequence of the tasks that have to be completed, affect overall organizational

  11. Joint Task Force East and Shared Military Basing in Romania and Bulgaria (Occasional Paper, Number 21)

    DTIC Science & Technology

    2009-08-01

    effectiveness in carrying out their full range of required tasks and missions. As expressed by Maj. Gen. Mircea Savu, Director of Operations at the...President Traian Basescu (who famously proposed a “Bucharest-London-Washington axis” in security policy) and Prime Minister Calin Tariceanu, both elected...on the key issues at stake. At the same time, the steadily-deteriorating relations between President Basescu and Prime Minister Tariceanu

  12. Effect of Exposure to an Authentic Pedagogical Task on Student Academic Performance, Student Perceptions of Pedagogical Authenticity and Higher Order Thinking

    ERIC Educational Resources Information Center

    Killen, Marlin

    2012-01-01

    The purpose of this study was to examine the effect of an authentic pedagogical (AP) task on measurements of student academic performance, student perceptions of pedagogical authenticity, and higher order thinking in undergraduate psychology courses. In this quasi-experimental design, comprehensive final exam scores, student ratings on the…

  13. Time location analysis for exposure assessment studies of indoor workers based on active RFID technology.

    PubMed

    Huang, Fu-Chuan; Shih, Tung-Sheng; Lee, Jiunn-Fwu; Chao, Huan-Ping; Wang, Peng-Yau

    2010-02-01

    In this article, we describe the development of a radio frequency identification exposure monitoring system (RFEMS) suitable for tracking and identifying workers' locations in indoor workplaces. Five workers in southern Taiwan wore the RFEMS integrated into their equipment vests. Location and exposure data were transferred to data analysis software for visualization and tabular analysis in real-time. Data were grouped into seven task activity location categories to determine the time spent and percentage reception in each location. The RFEMS could also synchronously indicate the surrounding conditions using various sensors. Additional experiments were focused on locating of boundaries and determining the instrument stability, power sustainability, and reception efficiency in typical environments. The RFEMS instruments provided adequate range for locating (typically ca. 6-45 m in each zone), allowing us to locate subjects within distinct microenvironments and to distinguish between the activities of a variety of workers, the average time activity pattern (TAP) recording deviation for both human observations and RFEMS was ca. 0.21-1.57%. Power consumption experiments revealed that the system could be sustained for more than 124 h. A pilot field test indicated that the RFEMS offers a new level of accuracy for direct quantification of time activity patterns in exposure assessments of indoor workers over long periods of time.

  14. Exposure Characteristics of Construction Painters to Organic Solvents

    PubMed Central

    Park, Hyunhee; Park, Hae Dong; Jang, Jae-Kil

    2015-01-01

    Background Construction painters have not been studied well in terms of their hazards exposure. The objective of this study was to evaluate the exposure levels of total volatile organic compounds (TVOCs) for painters in the construction industry. Methods Activity-specific personal air samplings were carried out in three waterproofing activities [polyurethane (PU), asphalt, and cement mortar] and three painting activities (epoxy, oil based, and water based) by using organic-vapor-monitor passive-sampling devices. Gas chromatograph with flame ionization detector could be used for identifying and quantifying individual organic chemicals. The levels of TVOCs, by summing up 15 targeted substances, were expressed in exposure-index (EI) values. Results As arithmetic means in the order of concentration levels, the EIs of TVOCs in waterproofing works were 10.77, 2.42, 1.78, 1.68, 0.47, 0.07, and none detected (ND) for indoor PU-primer task, outdoor PU-primer task, outdoor PU-resin task, indoor PU-resin task, asphalt-primer task, asphalt-adhesive task, and cement-mortar task, respectively. The highest EI for painting works was 5.61 for indoor epoxy-primer task, followed by indoor epoxy-resin task (2.03), outdoor oil-based-spray-paint task (1.65), outdoor water-based-paint task (0.66), and indoor oil-based-paint task (0.15). Assuming that the operations were carried out continuously for 8 hours without breaks and by using the arithmetic means of EIs for each of the 12 tasks in this study, 58.3% (7 out of 12) exceeded the exposure limit of 100% (EI > 1.0), while 8.3% (1 out of 12) was in 50–100% of exposure limit (0.5 > EI > 1.0), and 4 tasks out of 12 were located in less than 50% of the limit range (EI < 0.5). Conclusion From this study, we recognized that construction painters are exposed to various solvents, including carcinogens and reproductive toxins, and the levels of TVOC concentration in many of the painting tasks exceeded the exposure limits. Construction

  15. Development of risk-based nanomaterial groups for occupational exposure control

    PubMed Central

    Kuempel, E. D.; Castranova, V.; Geraci, C. L.; Schulte, P. A.

    2015-01-01

    Given the almost limitless variety of nanomaterials, it will be virtually impossible to assess the possible occupational health hazard of each nanomaterial individually. The development of science-based hazard and risk categories for nanomaterials is needed for decision-making about exposure control practices in the workplace. A possible strategy would be to select representative (benchmark) materials from various mode of action (MOA) classes, evaluate the hazard and develop risk estimates, and then apply a systematic comparison of new nanomaterials with the benchmark materials in the same MOA class. Poorly soluble particles are used here as an example to illustrate quantitative risk assessment methods for possible benchmark particles and occupational exposure control groups, given mode of action and relative toxicity. Linking such benchmark particles to specific exposure control bands would facilitate the translation of health hazard and quantitative risk information to the development of effective exposure control practices in the workplace. A key challenge is obtaining sufficient dose–response data, based on standard testing, to systematically evaluate the nanomaterials’ physical–chemical factors influencing their biological activity. Categorization processes involve both science-based analyses and default assumptions in the absence of substance-specific information. Utilizing data and information from related materials may facilitate initial determinations of exposure control systems for nanomaterials. PMID:26504427

  16. Assessment and comparison of total RF-EMF exposure in femtocell and macrocell base station scenarios.

    PubMed

    Aerts, Sam; Plets, David; Verloock, Leen; Martens, Luc; Joseph, Wout

    2014-12-01

    The indoor coverage of a mobile service can be drastically improved by deployment of an indoor femtocell base station (FBS). However, the impact of its proximity on the total exposure of the human body to radio-frequency (RF) electromagnetic fields (EMFs) is unknown. Using a framework designed for the combination of near-field and far-field exposure, the authors assessed and compared the RF-EMF exposure of a mobile-phone (MP) user that is either connected to an FBS or a conventional macrocell base station while in an office environment. It is found that, in average macrocell coverage and MP use-time conditions and for Universal Mobile Telecommunications System technology, the total exposure can be reduced by a factor of 20-40 by using an FBS, mostly due to the significant decrease in the output power of the MP. In general, the framework presented in this study can be used for any exposure scenario, featuring any number of technologies, base stations and/or access points, users and duration.

  17. Potential Occupational Exposures and Health Risks Associated with Biomass-Based Power Generation.

    PubMed

    Rohr, Annette C; Campleman, Sharan L; Long, Christopher M; Peterson, Michael K; Weatherstone, Susan; Quick, Will; Lewis, Ari

    2015-07-22

    Biomass is increasingly being used for power generation; however, assessment of potential occupational health and safety (OH&S) concerns related to usage of biomass fuels in combustion-based generation remains limited. We reviewed the available literature on known and potential OH&S issues associated with biomass-based fuel usage for electricity generation at the utility scale. We considered three potential exposure scenarios--pre-combustion exposure to material associated with the fuel, exposure to combustion products, and post-combustion exposure to ash and residues. Testing of dust, fungal and bacterial levels at two power stations was also undertaken. Results indicated that dust concentrations within biomass plants can be extremely variable, with peak levels in some areas exceeding occupational exposure limits for wood dust and general inhalable dust. Fungal spore types, identified as common environmental species, were higher than in outdoor air. Our review suggests that pre-combustion risks, including bioaerosols and biogenic organics, should be considered further. Combustion and post-combustion risks appear similar to current fossil-based combustion. In light of limited available information, additional studies at power plants utilizing a variety of technologies and biomass fuels are recommended.

  18. Potential Occupational Exposures and Health Risks Associated with Biomass-Based Power Generation

    PubMed Central

    Rohr, Annette C.; Campleman, Sharan L.; Long, Christopher M.; Peterson, Michael K.; Weatherstone, Susan; Quick, Will; Lewis, Ari

    2015-01-01

    Biomass is increasingly being used for power generation; however, assessment of potential occupational health and safety (OH&S) concerns related to usage of biomass fuels in combustion-based generation remains limited. We reviewed the available literature on known and potential OH&S issues associated with biomass-based fuel usage for electricity generation at the utility scale. We considered three potential exposure scenarios—pre-combustion exposure to material associated with the fuel, exposure to combustion products, and post-combustion exposure to ash and residues. Testing of dust, fungal and bacterial levels at two power stations was also undertaken. Results indicated that dust concentrations within biomass plants can be extremely variable, with peak levels in some areas exceeding occupational exposure limits for wood dust and general inhalable dust. Fungal spore types, identified as common environmental species, were higher than in outdoor air. Our review suggests that pre-combustion risks, including bioaerosols and biogenic organics, should be considered further. Combustion and post-combustion risks appear similar to current fossil-based combustion. In light of limited available information, additional studies at power plants utilizing a variety of technologies and biomass fuels are recommended. PMID:26206568

  19. Sun exposure behaviour among subgroups of the Danish population. Based on personal electronic UVR dosimetry and corresponding exposure diaries.

    PubMed

    Thieden, Elisabeth

    2008-02-01

    Solar ultraviolet radiation (UVR) is known to be the most important etiological factor in skin cancer development. The main objective of this thesis was to achieve an objective, basic knowledge of the individual UVR exposure dose pattern and to reveal the factors and with which power they influence on the UVR dose among the Danes. Eight open prospective, observational studies and one study analyzing the compliance and reliability of data were performed in healthy Danish volunteers with an age range of 4-68 years. The subjects were chosen to cover an age span group of children, adolescents, and indoor workers and in addition, groups with expected high UVR exposure, sun worshippers, golfers, and gardeners. We developed a personal, electronic UVR dosimeter in a wristwatch (SunSaver). The subjects wore the UVR dosimeter that measured time-stamped UVR doses in standard erythema doses (SED) and completed diaries with data on their sun exposure behaviour. This resulted in corresponding UVR dosimeter and diary data from 346 sun-years where one sun-year is one person participating in one summer half-year (median 119 days). The annual UVR doses were calculated based on the personal and ambient measured UVR doses. We found a huge variation in annual UVR exposure dose within the total population sample, median 173 SED (range, 17-980 SED). The inter-group variation in annual UVR dose was from median 132 SED among indoor workers to median 224 SED among gardeners. No significant correlation was found between annual UVR dose and age either within the total population or among the adults. But the subjects below 20 years of age had an increase in annual UVR dose of 5 SED per year. Young people before the age of 20 years did not get a higher proportion of the lifetime UVR dose than expected (25%) when assuming a life expectancy of 80 years. There was no significant difference in annual UVR dose between males and females in the total population sample. But, among children, girls

  20. Comparing response time, errors, and satisfaction between text-based and graphical user interfaces during nursing order tasks.

    PubMed

    Staggers, N; Kobus, D

    2000-01-01

    Despite the general adoption of graphical users interfaces (GUIs) in health care, few empirical data document the impact of this move on system users. This study compares two distinctly different user interfaces, a legacy text-based interface and a prototype graphical interface, for differences in nurses' response time (RT), errors, and satisfaction when the interfaces are used in the performance of computerized nursing order tasks. In a medical center on the East Coast of the United States, 98 randomly selected male and female nurses completed 40 tasks using each interface. Nurses completed four different types of order tasks (create, activate, modify, and discontinue). Using a repeated-measures and Latin square design, the study was counterbalanced for tasks, interface types, and blocks of trials. Overall, nurses had significantly faster response times (P < 0.0001) and fewer errors (P < 0.0001) using the prototype GUI than the text-based interface. The GUI was also rated significantly higher for satisfaction than the text system, and the GUI was faster to leam (P < 0.0001). Therefore, the results indicated that the use of a prototype GUI for nursing orders significantly enhances user performance and satisfaction. Consideration should be given to redesigning older user interfaces to create more modern ones by using human factors principles and input from user-centered focus groups. Future work should examine prospective nursing interfaces for highly complex interactions in computer-based patient records, detail the severity of errors made on line, and explore designs to optimize interactions in life-critical systems.