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1

Silica exposure during construction activities: statistical modeling of task-based measurements from the literature.  

PubMed

Many construction activities can put workers at risk of breathing silica containing dusts, and there is an important body of literature documenting exposure levels using a task-based strategy. In this study, statistical modeling was used to analyze a data set containing 1466 task-based, personal respirable crystalline silica (RCS) measurements gathered from 46 sources to estimate exposure levels during construction tasks and the effects of determinants of exposure. Monte-Carlo simulation was used to recreate individual exposures from summary parameters, and the statistical modeling involved multimodel inference with Tobit models containing combinations of the following exposure variables: sampling year, sampling duration, construction sector, project type, workspace, ventilation, and controls. Exposure levels by task were predicted based on the median reported duration by activity, the year 1998, absence of source control methods, and an equal distribution of the other determinants of exposure. The model containing all the variables explained 60% of the variability and was identified as the best approximating model. Of the 27 tasks contained in the data set, abrasive blasting, masonry chipping, scabbling concrete, tuck pointing, and tunnel boring had estimated geometric means above 0.1mg m(-3) based on the exposure scenario developed. Water-fed tools and local exhaust ventilation were associated with a reduction of 71 and 69% in exposure levels compared with no controls, respectively. The predictive model developed can be used to estimate RCS concentrations for many construction activities in a wide range of circumstances. PMID:23223272

Sauvé, Jean-François; Beaudry, Charles; Bégin, Denis; Dion, Chantal; Gérin, Michel; Lavoué, Jérôme

2013-05-01

2

Comparison of task-based exposure metrics for an epidemiologic study of isocyanate inhalation exposures among autobody shop workers.  

PubMed

Because many occupational epidemiologic studies use exposure surrogates rather than quantitative exposure metrics, the UMass Lowell and Yale study of autobody shop workers provided an opportunity to evaluate the relative utility of surrogates and quantitative exposure metrics in an exposure response analysis of cross-week change in respiratory function. A task-based exposure assessment was used to develop several metrics of inhalation exposure to isocyanates. The metrics included the surrogates, job title, counts of spray painting events during the day, counts of spray and bystander exposure events, and a quantitative exposure metric that incorporated exposure determinant models based on task sampling and a personal workplace protection factor for respirator use, combined with a daily task checklist. The result of the quantitative exposure algorithm was an estimate of the daily time-weighted average respirator-corrected total NCO exposure (microg/m(3)). In general, these four metrics were found to be variable in agreement using measures such as weighted kappa and Spearman correlation. A logistic model for 10% drop in FEV(1) from Monday morning to Thursday morning was used to evaluate the utility of each exposure metric. The quantitative exposure metric was the most favorable, producing the best model fit, as well as the greatest strength and magnitude of association. This finding supports the reports of others that reducing exposure misclassification can improve risk estimates that otherwise would be biased toward the null. Although detailed and quantitative exposure assessment can be more time consuming and costly, it can improve exposure-disease evaluations and is more useful for risk assessment purposes. The task-based exposure modeling method successfully produced estimates of daily time-weighted average exposures in the complex and changing autobody shop work environment. The ambient TWA exposures of all of the office workers and technicians and 57% of the painters were found to be below the current U.K. Health and Safety Executive occupational exposure limit (OEL) for total NCO of 20 microg/m(3). When respirator use was incorporated, all personal daily exposures were below the U.K. OEL. PMID:18615291

Woskie, Susan R; Bello, Dhimiter; Gore, Rebecca J; Stowe, Meredith H; Eisen, Ellen A; Liu, Youcheng; Sparer, Judy A; Redlich, Carrie A; Cullen, Mark R

2008-09-01

3

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

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

Svendsen, S; Mathiassen, S; Bonde, J

2005-01-01

4

The use of a task-based exposure assessment model (T-BEAM) for assessment of metal fume exposures during welding and thermal cutting.  

PubMed

Elevated disease rates have been documented among construction workers for cancer, pneumonoconiosis, asbestosis, and silicosis. However, methodologies for exposure assessment in construction are not well described in the U.S. literature. Working through a cooperative agreement with the National Institute for Occupational Safety and Health (NIOSH), the Center to Protect Workers' Rights--a research arm of the Building and Construction Trades Department, AFL-CIO--has developed and used a "Task-Based Exposure Assessment Model (T-BEAM)" for construction. The characteristic elements of T-BEAM are: (1) an emphasis on the identification, implementation, and evaluation of engineering and work practice controls; and (2) use of experienced, specially trained construction workers (construction safety and health specialists) in the exposure assessment process. A task-based approach was used because tasks, or specialized skills, form the single greatest thread of continuity in the dynamic environment of construction. Workers in the construction industry come from several crafts and are typically employed by a large number of contractors throughout their career. Project types (e.g., residential or industrial rehabilitation) are also highly variable and present unique health risks. Finally, because construction involves building, renovating, or dismantling physical surroundings, the work site is constantly changing. Between 1995 and 1996, T-BEAM was applied to the collection of approximately 200 personal exposure measurements associated with "hot work tasks"--welding and thermal cutting. Data were collected with the assistance of specially trained, journeyman ironworkers, pipe fitters, and boilermakers on nine construction sites located throughout the United States. Portable local exhaust ventilation was provided to participating contractors with the intent of measuring its impact on exposure. Results indicate that data collected in a standardized, systematic fashion from multiple work sites can be used to characterize exposures among sampled trades. Comparison of results to American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit values (TLVs) demonstrate a significant health hazard among sampled trades posed by welding and thermal cutting fume, manganese, nickel, and chromium VI. Direct estimates of the probability of exceeding the ACGIH TLV for respirable particulate suggests that boilermakers (100%) and ironworkers (71%) are at greatest risk. Other task variables evaluated with respect to exposure include task, whether work was performed indoors or outdoors, intermittency of work, and use of ventilation. Use of local or mechanical ventilation reduced mean exposures to fumes significantly. PMID:10660986

Susi, P; Goldberg, M; Barnes, P; Stafford, E

2000-01-01

5

Scenario-Based Tasks  

NSDL National Science Digital Library

This page from The Experiential Learning Center provides a number of scenario-based tasks for use in the classroom or for professional development training. The materials are freely available for download and use and would be applicable to learners in a variety of subjects including software development, faculty professional development, office system applications/ICT, biology/bioinformatics, environmental studies, Python programming, engineering, network security/MIS, computational thinking and English writing. Instructor guides and other classroom instructional materials are provided. The project requests that educators let them know when these materials are used in order to track dissemination of the work and in order to inform the community about upcoming workshops and presentations.

2012-10-09

6

Agricultural Task and Exposure to Organophosphate Pesticides Among Farmworkers  

Microsoft Academic Search

Little is known about pesticide exposure among farmworkers, and even less is known about the exposure associated with performing specific farm tasks. Using a random sample of 213 farm- workers in 24 communities and labor camps in eastern Washington State, we examined the associ- ation between occupational task and organophosphate (OP) pesticide residues in dust and OP metabolite concentrations in

Gloria D. Coronado; Beti Thompson; Larkin Strong; William C. Griffith; Ilda Islas

2003-01-01

7

Hexavalent chromium exposure and control in welding tasks.  

PubMed

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 ?g/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 substantially reduced with proper use of LEV. PMID:20845207

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

2010-11-01

8

Quantitative assessment of airborne exposures generated during common cleaning tasks: a pilot study  

PubMed Central

Background A growing body of epidemiologic evidence suggests an association between exposure to cleaning products with asthma and other respiratory disorders. Thus far, these studies have conducted only limited quantitative exposure assessments. Exposures from cleaning products are difficult to measure because they are complex mixtures of chemicals with a range of physicochemical properties, thus requiring multiple measurement techniques. We conducted a pilot exposure assessment study to identify methods for assessing short term, task-based airborne exposures and to quantitatively evaluate airborne exposures associated with cleaning tasks simulated under controlled work environment conditions. Methods Sink, mirror, and toilet bowl cleaning tasks were simulated in a large ventilated bathroom and a small unventilated bathroom using a general purpose, a glass, and a bathroom cleaner. All tasks were performed for 10 minutes. Airborne total volatile organic compounds (TVOC) generated during the tasks were measured using a direct reading instrument (DRI) with a photo ionization detector. Volatile organic ingredients of the cleaning mixtures were assessed utilizing an integrated sampling and analytic method, EPA TO-17. Ammonia air concentrations were also measured with an electrochemical sensor embedded in the DRI. Results Average TVOC concentrations calculated for 10 minute tasks ranged 0.02 - 6.49 ppm and the highest peak concentrations observed ranged 0.14-11 ppm. TVOC time concentration profiles indicated that exposures above background level remained present for about 20 minutes after cessation of the tasks. Among several targeted VOC compounds from cleaning mixtures, only 2-BE was detectable with the EPA method. The ten minute average 2- BE concentrations ranged 0.30 -21 ppm between tasks. The DRI underestimated 2-BE exposures compared to the results from the integrated method. The highest concentration of ammonia of 2.8 ppm occurred during mirror cleaning. Conclusions Our results indicate that airborne exposures from short-term cleaning tasks can remain in the air even after tasks' cessation, suggesting potential exposures to anyone entering the room shortly after cleaning. Additionally, 2-BE concentrations from cleaning could approach occupational exposure limits and warrant further investigation. Measurement methods applied in this study can be useful for workplace assessment of airborne exposures during cleaning, if the limitations identified here are addressed. PMID:21118559

2010-01-01

9

Accuracy of task recall for epidemiological exposure assessment to construction noise  

PubMed Central

Aims: To validate the accuracy of construction worker recall of task and environment based information; and to evaluate the effect of task recall on estimates of noise exposure. Methods: A cohort of 25 construction workers recorded tasks daily and had dosimetry measurements weekly for six weeks. Worker recall of tasks reported on the daily activity cards was validated with research observations and compared directly to task recall at a six month interview. Results: The mean LEQ noise exposure level (dBA) from dosimeter measurements was 89.9 (n = 61) and 83.3 (n = 47) for carpenters and electricians, respectively. The percentage time at tasks reported during the interview was compared to that calculated from daily activity cards; only 2/22 tasks were different at the nominal 5% significance level. The accuracy, based on bias and precision, of percentage time reported for tasks from the interview was 53–100% (median 91%). For carpenters, the difference in noise estimates derived from activity cards (mean 91.9 dBA) was not different from those derived from the questionnaire (mean 91.7 dBA). This trend held for electricians as well. For all subjects, noise estimates derived from the activity card and the questionnaire were strongly correlated with dosimetry measurements. The average difference between the noise estimate derived from the questionnaire and dosimetry measurements was 2.0 dBA, and was independent of the actual exposure level. Conclusions: Six months after tasks were performed, construction workers were able to accurately recall the percentage time they spent at various tasks. Estimates of noise exposure based on long term recall (questionnaire) were no different from estimates derived from daily activity cards and were strongly correlated with dosimetry measurements, overestimating the level on average by 2.0 dBA. PMID:14739379

Reeb-Whitaker, C; Seixas, N; Sheppard, L; Neitzel, R

2004-01-01

10

Cosmetology: Task Analyses. Competency-Based Education.  

ERIC Educational Resources Information 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 courses…

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

11

Cue-based preparation and stimulus-based priming of tasks in task switching  

Microsoft Academic Search

In this study, we investigated the interaction of three different sources of task activation in precued task switching. We\\u000a distinguished (1) intentional, cue-based task activation from two other, involuntary sources of activation: (2) persisting\\u000a activation from the preceding task and (3) stimulus-based task activation elicited by the task stimulus itself. We assumed\\u000a that cue-based task activation increases as a function

Iring Koch; Alan Allport

2006-01-01

12

Task-Based Information Searching.  

ERIC Educational Resources Information Center

Reviews studies on the relationship between task performance and information searching by end-users, focusing on information searching in electronic environments and information retrieval systems. Topics include task analysis; task characteristics; search goals; modeling information searching; modeling search goals; information seeking behavior;…

Vakkari, Pertti

2003-01-01

13

Agricultural task and exposure to organophosphate pesticides among farmworkers.  

PubMed Central

Little is known about pesticide exposure among farmworkers, and even less is known about the exposure associated with performing specific farm tasks. Using a random sample of 213 farmworkers in 24 communities and labor camps in eastern Washington State, we examined the association between occupational task and organophosphate (OP) pesticide residues in dust and OP metabolite concentrations in urine samples of adult farmworkers and their children. The data are from a larger study that sought to test a culturally appropriate intervention to break the take-home pathway of pesticide exposure. Commonly reported farm tasks were harvesting or picking (79.2%), thinning (64.2%), loading plants or produce (42.2%), planting or transplanting (37.6%), and pruning (37.2%). Mixing, loading, or applying pesticide formulations was reported by 20% of our sample. Workers who thinned were more likely than those who did not to have detectable levels of azinphos-methyl in their house dust (92.1% vs. 72.7%; p = 0.001) and vehicle dust (92.6% vs. 76.5%; p = 0.002). Thinning was associated with higher urinary pesticide metabolite concentrations in children (91.9% detectable vs. 81.3%; p = 0.02) but not in adults. Contrary to expectation, workers who reported mixing, loading, or applying pesticide formulations had lower detectable levels of pesticide residues in their house or vehicle dust, compared with those who did not perform these job tasks, though the differences were not significant. Future research should evaluate workplace protective practices of fieldworkers and the adequacy of reentry intervals for pesticides used during thinning. PMID:14754567

Coronado, Gloria D; Thompson, Beti; Strong, Larki; Griffith, William C; Islas, Ilda

2004-01-01

14

Stimulus-Based Priming of Task Choice during Voluntary Task Switching  

ERIC Educational Resources Information Center

Two voluntary task-switching experiments probed the influence of previous exposures to stimuli and categorizations of these stimuli on task choice during subsequent exposures to the same stimuli. Subjects performed origin and size judgments under standard voluntary task-switching instructions to perform the tasks equally often in a random order.…

Arrington, Catherine M.; Weaver, Starla M.; Pauker, Rachel L.

2010-01-01

15

TASK 2.5.5 NATURAL EXPOSURE TESTING IN CALIFORNIA  

SciTech Connect

Airborne particulate matter that settles on a roof can either reflect or absorb incoming solar radiation, dependent on the chemical content and size of the particles. These light scattering and absorption processes occur within a few microns of the surface, and can affect the solar reflectance of the roof. Wilkes et al. (2000) tested 24 different roof coatings on a low-slope test stand and observed about a 25% decrease in the solar reflectance of white-coated and aluminum-coated surfaces as the time of exposure increased; however, the decrease leveled off after 2 years. SPRI Inc. and its affiliates studied the effect of climatic exposure on the surface properties of white thermoplastic single-ply membranes and determined that membranes lose from 30 to 50% of their reflectance over 3 years (Miller et al. 2002). The CMRC and its affiliates AISI, NamZAC, MBMA, MCA and NCCA exposed unpainted and painted metal roofing on both steep- and low-slope test roofs and found that after 3 years, the painted polyvinylidene fluoride (PVDF) metal roofs lost less than 5% of their original reflectance (Miller et al. 2004). The results of the three different weathering studies are very interesting in terms of their solar reflectance after 3 years of exposure. The white thermoplastic membrane and white ceramic coating with white topcoat had original reflectance measures that were about 20 percentage points higher than the painted metal; however, after 3-years of field exposure the solar reflectance of the painted metal exceeds that of the thermoplastic membrane and equals that of the coating. The long-term loss of reflectance appears driven by the ability of the particulate matter to cling to the roof and resist being washed off by wind and or rain. Miller et al. (2002) discovered that aerosol deposition introduced biomass of complex microbial consortia onto the test roofs and the combination of contaminants and biomass accelerated the loss of solar reflectance for the thermoplastic 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 least 0.5 and visually shows the accumulation of airborne contaminants. The thermal emittance r

Miller, William A [ORNL; Cheng, Mengdawn [ORNL; New, Joshua Ryan [ORNL; Ronnen, Levinson [Lawrence Berkeley National Laboratory (LBNL); Akbari, Hashem [Lawrence Berkeley National Laboratory (LBNL); Berhahl, Paul [Lawrence Berkeley National Laboratory (LBNL)

2010-03-01

16

Characterization of occupational exposures to cleaning products used for common cleaning tasks-a pilot study of hospital cleaners  

PubMed Central

Background In recent years, cleaning has been identified as an occupational risk because of an increased incidence of reported respiratory effects, such as asthma and asthma-like symptoms among cleaning workers. Due to the lack of systematic occupational hygiene analyses and workplace exposure data, it is not clear which cleaning-related exposures induce or aggravate asthma and other respiratory effects. Currently, there is a need for systematic evaluation of cleaning products ingredients and their exposures in the workplace. The objectives of this work were to: a) identify cleaning products' ingredients of concern with respect to respiratory and skin irritation and sensitization; and b) assess the potential for inhalation and dermal exposures to these ingredients during common cleaning tasks. Methods We prioritized ingredients of concern in cleaning products commonly used in several hospitals in Massachusetts. Methods included workplace interviews, reviews of product Materials Safety Data Sheets and the scientific literature on adverse health effects to humans, reviews of physico-chemical properties of cleaning ingredients, and occupational hygiene observational analyses. Furthermore, the potential for exposure in the workplace was assessed by conducting qualitative assessment of airborne exposures and semi-quantitative assessment of dermal exposures. Results Cleaning products used for common cleaning tasks were mixtures of many chemicals, including respiratory and dermal irritants and sensitizers. Examples of ingredients of concern include quaternary ammonium compounds, 2-butoxyethanol, and ethanolamines. Cleaning workers are at risk of acute and chronic inhalation exposures to volatile organic compounds (VOC) vapors and aerosols generated from product spraying, and dermal exposures mostly through hands. Conclusion Cleaning products are mixtures of many chemical ingredients that may impact workers' health through air and dermal exposures. Because cleaning exposures are a function of product formulations and product application procedures, a combination of product evaluation with workplace exposure assessment is critical in developing strategies for protecting workers from cleaning hazards. Our task based assessment methods allowed classification of tasks in different exposure categories, a strategy that can be employed by epidemiological investigations related to cleaning. The methods presented here can be used by occupational and environmental health practitioners to identify intervention strategies. PMID:19327131

2009-01-01

17

Task-Based Profiles of the Dysarthrias  

Microsoft Academic Search

The dysarthrias are associated with a variety of motor disturbances distributed over several motor systems of speech production. The features of a given dysarthria often vary with the speaking task, and this task-dependency affords insights into the responsible neural lesion and its effects on the motor regulation of speech. Each task also is amenable to quantitative analyses with acoustic or

Raymond D. Kent; Jane Finley Kent

2000-01-01

18

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

SciTech Connect

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.

Whittington, C.J.; Podd, J.V.; Rapley, B.R. [Massey Univ., Palmerston North (New Zealand). Dept. of Psychology] [Massey Univ., Palmerston North (New Zealand). Dept. of Psychology

1996-05-01

19

Collaborative relevance assessment for task-based knowledge support  

Microsoft Academic Search

The operations and management activities of enterprises are mainly task-based and knowledge intensive. Accordingly, an important issue in deploying knowledge management systems is the provision of task-relevant information (codified knowledge) to meet the information needs of knowledge workers during the execution of a task. Codified knowledge extracted from previously executed tasks can provide valuable knowledge about conducting the task-at-hand (current

Duen-ren Liu; I-chin Wu

2008-01-01

20

Different computer tasks affect the exposure of the upper extremity to biomechanical risk factors  

Microsoft Academic Search

In order to determine differences in biomechanical risk factors across computer tasks, a repeated measures laboratory experiment was completed with 30 touch-typing adults (15 females and 15 males). The participants completed five different computer tasks: typing text, completing an html-based form with text fields, editing text within a document, sorting and resizing objects in a graphics task and browsing and

Jack T. Dennerlein; Peter W. Johnson

2006-01-01

21

Developing a driving simulator based functional object detection task.  

PubMed

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. PMID:23899199

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

2012-10-01

22

Task based weights for spectral computed tomography  

NASA Astrophysics Data System (ADS)

In photon counting multi-bin CT, both projection based weighting and image based weighting (designed to maximize the signal-difference-to-noise ratio SDNR) in the final image, are pixel based and do not account for any spatial frequency dependency of signal and noise among the bins. The same weighting scheme will be used when imaging objects with a large fraction of high spatial frequencies and those with predominantly low spatial frequency content. Any effect on the detectability of a certain target due to correlation between detector elements and bins that might arise in pulse height discriminating systems will not be captured using such an approach. We show how to take the spatial frequency dependency of signal and noise transfer for each bin, and the spatial frequency composition of a target, into account when determining optimal task based weights for photon-counting multi-bin CT imaging using the 2D slice detectability index by applying cascaded system analysis to a spectrally resolved photon counting CT detector system with multiple bins.

Yveborg, Moa; Danielsson, Mats; Bornefalk, Hans

2012-03-01

23

Exposure to Repetitive Tasks Induces Motor Changes Related to Skill Acquisition and Inflammation in Rats  

Microsoft Academic Search

The authors elucidate exposure-response relationships between repetitive tasks, inflammation, and motor changes with work-related musculoskeletal disorders. Using a rat model of reaching and handle pulling, they examined effects of performing a high-repetition, low-force (HRLF); low-repetition, high-force (LRHF); or high-repetition, high-force (HRHF) task (2 hr\\/day, 3 days\\/week, 12 weeks) on reach rate and force, percentage of successful reaches, duration of participation,

David M. Kietrys; Ann E. Barr; Mary F. Barbe

2011-01-01

24

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

PubMed Central

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

Heilskov-Hansen, Thomas; Wulff Svendsen, Susanne; Fr?lund Thomsen, Jane; Mikkelsen, Sigurd; Hansson, Gert-Ake

2014-01-01

25

Inhalable dust exposures, tasks, and use of ventilation in small woodworking shops: a pilot study.  

PubMed

Measures of workers' inhalable dust exposures, tasks, and ventilation use were made in five small woodworking shops prior to the start of an intervention effectiveness study aimed at lowering personal wood dust exposures. The data were used to (1) design a sampling protocol for an intervention success measure, (2) identify targets for intervention among the tasks and activities responsible for high dust levels, and (3) develop shop-level measures as tools for tailoring intervention activities. Geometric mean dust concentrations ranged from 1.6 to 9.9 mg/m3 in the five shops, with the highest levels occurring in a cabinet shop. All shops had centralized dust collection systems and workers generally used dust control on stationary tools (60-100% of the time) when it was available. Sanding with both stationary and handheld powered tools, cleaning with methods that can disperse dust (e.g., brushes, compressed air), and miscellaneous tasks were all responsible for significant personal exposures. The positive association between miscellaneous tasks and exposures probably reflects the high background levels generated by nearby processes. Sanding with both stationary tools and handheld powered tools represents the most significant influence on personal exposures in small woodworking shops. The authors conclude that pilot studies are useful tools for designing occupational health and safety intervention effectiveness studies. PMID:11434438

Brosseau, L M; Parker, D; Lazovich, D; Dugan, S; Milton, T; Pan, W

2001-01-01

26

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

ERIC Educational Resources Information Center

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…

Kirkgoz, Yasemin

2011-01-01

27

Task-based decomposition of factored POMDPs.  

PubMed

Recently, partially observable Markov decision processes (POMDP) solvers have shown the ability to scale up significantly using domain structure, such as factored representations. In many domains, the agent is required to complete a set of independent tasks. We propose to decompose a factored POMDP into a set of restricted POMDPs over subsets of task relevant state variables. We solve each such model independently, acquiring a value function. The combination of the value functions of the restricted POMDPs is then used to form a policy for the complete POMDP. We explain the process of identifying variables that correspond to tasks, and how to create a model restricted to a single task, or to a subset of tasks. We demonstrate our approach on a number of benchmarks from the factored POMDP literature, showing that our methods are applicable to models with more than 100 state variables. PMID:23757544

Shani, Guy

2014-02-01

28

Abuse Pattern of Toluene Exposure Alters Mouse Behavior in a Waiting-for-Reward Operant Task  

PubMed Central

Inhaling solvents for recreational purposes continues to be a world-wide public health concern. Toluene, a volatile solvent in many abused products, adversely affects the central nervous system. However, the long-term neurobehavioral effects of exposure to high-concentration, binge patterns typical of toluene abuse remain understudied. We studied the behavioral effects of repeated toluene exposure on cognitive function following binge toluene exposure on behavioral impulse control in Swiss Webster mice using a “wait-for-reward” operant task. Mice were trained on a fixed-ratio (FR) schedule using sweetened milk as a reward. Upon achieving FR15, a wait component was added which delivered free rewards in the absence of responses at increasing time intervals (2 sec, 4 sec, 6 sec, etc…). Mice continued to receive free rewards until they pressed a lever that reinstated the FR component (FR Reset). Once proficient in the FR-Wait task, mice were exposed to either 1,000 ppm, 3,600 ppm or 6,000 ppm toluene, or 0 ppm (air controls) for 30 min per day for 40 days. To avoid acute effects of toluene exposure, behavior was assessed 23 hours later. Repeated toluene exposure decreased response rates, the number of FR resets, and increased mean wait time, resulting in a higher response-to-reinforcer ratio than exhibited by controls. Mice receiving the higher exposure level (6,000 ppm) showed a dramatic decrease in the number of rewards received, which was reversed when toluene exposure ceased. Mice receiving the lower exposure level (1,000 ppm) showed little change in the number of rewards. These results indicate that repeated binge exposures to high concentrations of toluene can significantly interfere with performance as measured by a waiting-for-reward task, suggesting a significant impact on cognitive and/or psychomotor function. PMID:18832024

Bowen, Scott E.; McDonald, Phillip

2009-01-01

29

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

PubMed

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. PMID:24796598

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

2014-12-01

30

Designing Digital Problem Based Learning Tasks that Motivate Students  

ERIC Educational Resources Information Center

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…

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

2013-01-01

31

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

ERIC Educational Resources Information Center

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…

Georgia State Univ., Atlanta. School of Education.

32

A Task-Based Approach to Adaptive and Multimodality Imaging  

PubMed Central

Multimodality imaging is becoming increasingly important in medical imaging. Since the motivation for combining multiple imaging modalities is generally to improve diagnostic or prognostic accuracy, the benefits of multimodality imaging cannot be assessed through the display of example images. Instead, we must use objective, task-based measures of image quality to draw valid conclusions about system performance. In this paper, we will present a general framework for utilizing objective, task-based measures of image quality in assessing multimodality and adaptive imaging systems. We introduce a classification scheme for multimodality and adaptive imaging systems and provide a mathematical description of the imaging chain along with block diagrams to provide a visual illustration. We show that the task-based methodology developed for evaluating single-modality imaging can be applied, with minor modifications, to multimodality and adaptive imaging. We discuss strategies for practical implementing of task-based methods to assess and optimize multimodality imaging systems. PMID:19079563

Clarkson, Eric; Kupinski, Matthew A.; Barrett, Harrison H.; Furenlid, Lars

2008-01-01

33

Consensus-based auctions for decentralized task assignment  

E-print Network

This thesis addresses the decentralized task assignment problem in cooperative autonomous search and track missions by presenting the Consensus-Based class of assignment algorithms. These algorithm make use of information ...

Brunet, Luc (Luc P. V.)

2008-01-01

34

Age-Based Differences in Strategy Use in Choice Tasks  

PubMed Central

We incorporated behavioral and computational modeling techniques to examine age-based differences in strategy use in two four-choice decision-making tasks. Healthy older (aged 60–82?years) and younger adults (aged 18–23?years) performed one of two decision-making tasks that differed in the degree to which rewards for each option depended on the choices made on previous trials. In the choice-independent task rewards for each choice were not affected by the sequence of previous choices that had been made. In contrast, in the choice-dependent task rewards for each option were based on how often each option had been chosen in the past. We compared the fits of a model that assumes the use of a win-stay–lose-shift (WSLS) heuristic to make decisions, to the fits of a reinforcement-learning (RL) model that compared expected reward values for each option to make decisions. Younger adults were best fit by the RL model, while older adults showed significantly more evidence of being best fit by the WSLS heuristic model. This led older adults to perform worse than younger adults in the choice-independent task, but better in the choice-dependent task. These results coincide with previous work in our labs that also found better performance for older adults in choice-dependent tasks (Worthy et al., 2011), and the present results suggest that qualitative age-based differences in the strategies used in choice tasks may underlie older adults’ advantage in choice-dependent tasks. We discuss possible factors behind these differences such as neurobiological changes associated with aging, and increased use of heuristics by older adults. PMID:22232573

Worthy, Darrell A.; Maddox, W. Todd

2012-01-01

35

Enhanced multi-task compressive sensing using Laplace priors and MDL-based task classification  

NASA Astrophysics Data System (ADS)

In multi-task compressive sensing (MCS), the original signals of multiple compressive sensing (CS) tasks are assumed to be correlated. This is explored to recover signals in a joint manner to improve signal reconstruction performance. In this paper, we first develop an improved version of MCS that imposes sparseness over the original signals using Laplace priors. The newly proposed technique, termed as the Laplace prior-based MCS (LMCS), adopts a hierarchical prior model, and the MCS is shown analytically to be a special case of LMCS. This paper next considers the scenario where the CS tasks belong to different groups. In this case, the original signals from different task groups are not well correlated, which would degrade the signal recovery performance of both MCS and LMCS. We propose the use of the minimum description length (MDL) principle to enhance the MCS and LMCS techniques. New algorithms, referred to as MDL-MCS and MDL-LMCS, are developed. They first classify tasks into different groups and then reconstruct signals from each cluster jointly. Simulations demonstrate that the proposed algorithms have better performance over several state-of-art benchmark techniques.

Wang, Ying-Gui; Yang, Le; Tang, Liang; Liu, Zheng; Jiang, Wen-Li

2013-12-01

36

Towards continualized task-based resolution modeling in PET imaging  

NASA Astrophysics Data System (ADS)

We propose a generalized resolution modeling (RM) framework, including extensive task-based optimization, wherein we continualize the conventionally discrete framework of RM vs. no RM, to include varying degrees of RM. The proposed framework has the advantage of providing a trade-off between the enhanced contrast recovery by RM and the reduced inter-voxel correlations in the absence of RM, and to enable improved task performance. The investigated context was that of oncologic lung FDG PET imaging. Given a realistic blurring kernel of FWHM h (`true PSF'), we performed iterative EM including RM using a wide range of `modeled PSF' kernels with varying widths h. In our simulations, h = 6mm, while h varied from 0 (no RM) to 12mm, thus considering both underestimation and overestimation of the true PSF. Detection task performance was performed using prewhitened (PWMF) and nonprewhitened matched filter (NPWMF) observers. It was demonstrated that an underestimated resolution blur (h = 4mm) enhanced task performance, while slight over-estimation (h = 7mm) also achieved enhanced performance. The latter is ironically attributed to the presence of ringing artifacts. Nonetheless, in the case of the NPWMF, the increasing intervoxel correlations with increasing values of h degrade detection task performance, and underestimation of the true PSF provides the optimal task performance. The proposed framework also achieves significant improvement of reproducibility, which is critical in quantitative imaging tasks such as treatment response monitoring.

Ashrafinia, Saeed; Karakatsanis, Nicolas; Mohy-ud-Din, Hassan; Rahmim, Arman

2014-03-01

37

Effects on Automatic Attention Due to Exposure to Pictures of Emotional Faces while Performing Chinese Word Judgment Tasks  

PubMed Central

Two experiments were conducted to investigate the automatic processing of emotional facial expressions while performing low or high demand cognitive tasks under unattended conditions. In Experiment 1, 35 subjects performed low (judging the structure of Chinese words) and high (judging the tone of Chinese words) cognitive load tasks while exposed to unattended pictures of fearful, neutral, or happy faces. The results revealed that the reaction time was slower and the performance accuracy was higher while performing the low cognitive load task than while performing the high cognitive load task. Exposure to fearful faces resulted in significantly longer reaction times and lower accuracy than exposure to neutral faces on the low cognitive load task. In Experiment 2, 26 subjects performed the same word judgment tasks and their brain event-related potentials (ERPs) were measured for a period of 800 ms after the onset of the task stimulus. The amplitudes of the early component of ERP around 176 ms (P2) elicited by unattended fearful faces over frontal-central-parietal recording sites was significantly larger than those elicited by unattended neutral faces while performing the word structure judgment task. Together, the findings of the two experiments indicated that unattended fearful faces captured significantly more attention resources than unattended neutral faces on a low cognitive load task, but not on a high cognitive load task. It was concluded that fearful faces could automatically capture attention if residues of attention resources were available under the unattended condition. PMID:24124486

Junhong, Huang; Renlai, Zhou; Senqi, Hu

2013-01-01

38

Task- and time-dependent weighting factors in a retrospective exposure assessment of chemical laboratory workers.  

PubMed

A chemical exposure assessment 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, Tennessee, and Aiken, South Carolina. Previous studies of chemical laboratory workers have included members within professional societies where exposure assessment was either limited or not feasible, or chemical processing employees where laboratory and production workers were combined. Because sufficient industrial hygiene records were unavailable for all four sites, weighted duration of employment was used as a surrogate for the magnitude of exposure. Potential exposure indices were calculated for each worker using number of days employed and weighting factors for frequency of contact and year of employment. A total of 591 unique laboratory job titles indicative of a chemical laboratory worker were collapsed into 18 general job title categories. Through discussions with current and retired workers, along with examination of historical organizational charts and job descriptions, the percentage of time with activities involving the direct handling of chemicals in the laboratory was estimated for each job title category. Scaled weighting factors of 1, 0.6, 0.3, and 0.05 were assigned to the job title categories representing 100%, 60%, 30%, and 5% of daily activities handling chemicals, respectively. Based on limited industrial hygiene monitoring data, personal radiation monitoring records, and professional judgment, weighting factors that declined 4% annually were applied to each year to account for improvements in laboratory technique, advancements in instrumentation, improvement in engineering controls, and increased safety awareness through time. The study cohort was separated into three categories of chemical exposures based on department level information: (1) inorganic, (2) mixed inorganic and organic, and (3) unknown. Potential exposure indices ranged from 0.15 to 6824.5 with a median value of 377.5 and a mean equal to 884.2. This exposure assessment method is useful for epidemiologic analyses when quantitative exposure data are absent or insufficient. PMID:17175512

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

2007-02-01

39

Exposure levels of farmers and veterinarians to particulate matter and gases uring operational tasks in pig-fattening houses.  

PubMed

The main objective of the study was to assess particulate matter (PM) exposure levels for both the farmer and the veterinarian during different operational tasks in pig-fattening houses, and to estimate their exposure levels on a daily working basis (time-weighted average (TWA)). The measured PM fractions were: inhalable and respirable PM, PM10, PM2.5 and PM1. The effects of pig age, pen floor type (conventional or low emission surface) and cleaning of the pens on the personal PM exposure were also investigated. Indoor concentrations of NH3, CH4, and CO2 were additionally measured during some operational tasks. The results showed that personal exposure levels can become extremely high during some operational tasks performed by the farmer or veterinarian. The highest concentration levels were observed during feed shovelling and blood sampling, the lowest during the weighing of the pigs. For the farmer, the estimated TWA exposure levels of inhalable and respirable PM were 6.0 and 0.29 mg m (-3) , respectively. These exposure levels for the veterinarian were, respectively, 10.6 and 0.74 mg m (-3) . The PM concentration levels were mainly determined by the performed operational tasks. There was no significant effect of pig age, pen floor type, nor cleaning of the pens on the personal exposure levels. PMID:25292112

Van Ransbeeck, Nele; Van Langenhove, Herman; Michiels, Annelies; Sonck, Bart; Demeyer, Peter

2014-09-01

40

Verification duty policy for task-role-based workflow systems  

NASA Astrophysics Data System (ADS)

A broad literature review presents great interests about theoretical specification or various formalizations on the constraints of Separation of Duty (SoD) Policy, which can improve Role-Based Access Control (RBAC). To gain the flexible and specific access control of information exchange within the enterprise environment, the proposed verification algorithm can check whether or not the Task-Role-Based Access Control (TRBAC) state can be satisfied with an assigned type of SoD policy, according to different given role-task and user-role assignments.

Dong, Honglin; Liu, Yiliang; Huang, Qin; Yang, Tianyi; Ma, Fang

2009-12-01

41

Verification duty policy for task-role-based workflow systems  

NASA Astrophysics Data System (ADS)

A broad literature review presents great interests about theoretical specification or various formalizations on the constraints of Separation of Duty (SoD) Policy, which can improve Role-Based Access Control (RBAC). To gain the flexible and specific access control of information exchange within the enterprise environment, the proposed verification algorithm can check whether or not the Task-Role-Based Access Control (TRBAC) state can be satisfied with an assigned type of SoD policy, according to different given role-task and user-role assignments.

Dong, Honglin; Liu, Yiliang; Huang, Qin; Yang, Tianyi; Ma, Fang

2010-01-01

42

3Ps, Task-Based Learning, and the Japanese Learner.  

ERIC Educational Resources Information Center

Summarizes the findings of a work in progress that attempted to investigate to what extent task-based learning was more effective than the 3Ps approach in the teaching of Japanese as a foreign language in Thailand. (Author/VWL)

Tanasarnsanee, Mika

2002-01-01

43

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

PubMed Central

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. PMID:19673189

Shepard, S. Jeff; Wang, Jihong; Flynn, Michael; Gingold, Eric; Goldman, Lee; Krugh, Kerry; Leong, David L.; Mah, Eugene; Ogden, Kent; Peck, Donald; Samei, Ehsan; Wang, Jihong; Willis, Charles E.

2009-01-01

44

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

SciTech Connect

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.

Shepard, S. Jeff; Wang Jihong; Flynn, Michael [Imaging Physics Department 056, Division of Diagnostic Imaging, University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, Texas 77030 (United States); and others

2009-07-15

45

Evaluating the Semantic Web: A Task-Based Approach  

NASA Astrophysics Data System (ADS)

The increased availability of online knowledge has led to the design of several algorithms that solve a variety of tasks by harvesting the Semantic Web, i.e., by dynamically selecting and exploring a multitude of online ontologies. Our hypothesis is that the performance of such novel algorithms implicitly provides an insight into the quality of the used ontologies and thus opens the way to a task-based evaluation of the Semantic Web. We have investigated this hypothesis by studying the lessons learnt about online ontologies when used to solve three tasks: ontology matching, folksonomy enrichment, and word sense disambiguation. Our analysis leads to a suit of conclusions about the status of the Semantic Web, which highlight a number of strengths and weaknesses of the semantic information available online and complement the findings of other analysis of the Semantic Web landscape.

Sabou, Marta; Gracia, Jorge; Angeletou, Sofia; D'Aquin, Mathieu; Motta, Enrico

46

A task-based metric for telerobotic performance assessment  

NASA Technical Reports Server (NTRS)

A methodology is described for developing a task complexity index based on combining the six basic motion primitives (three translation, three orientation) with force control and accuracy requirements. The result of this development is a set of complexity values that can be assigned to the high-level task primitives derived from a relatively shallow top-down mission analysis. These values are then averaged to arrive at total average mission complexities, such as for the mission of exchanging the Hubble Space Telescope (HST) battery modules. Application of this metric to a candidate set of NASA Flight Telerobotic Servicer evaluation tasks is discussed using the HST battery module mission for an in-depth example.

Barnes, J. F.

1987-01-01

47

Component based interface to handle tasks during claim processing  

US Patent & Trademark Office Database

A computer program is provided for developing component based software capable of handling insurance-related tasks. The program includes a data component that stores, retrieves and manipulates data utilizing a plurality of functions. Also provided is a client component that includes an adapter component that transmits and receives data to/from the data component. The client component also includes a business component that serves as a data cache and includes logic for manipulating the data. A controller component is also included which is adapted to handle events generated by a user utilizing the business component to cache data and the adapter component to ultimately persist data to a data repository. In use, the client component is suitable for receiving a plurality of tasks that achieve an insurance-related goal upon completion, allowing users to add new tasks that achieve the goal upon completion, allowing the users to edit the tasks, and generating a historical record of the tasks that are completed.

2006-03-14

48

A physiological response (plasma cyclic amp) and a psychological response (STAI-A-state) to noise exposure and/or calculation task  

NASA Astrophysics Data System (ADS)

The effects of 90 dB(A) noise exposure and/or a calculation task on plasma cyclic AMP concentrations (physiological index) and STAI-A-State scores (psychological index) in normal subjects are compared. Neither the plasma cyclic AMP concentration nor the STAI-A-State scores showed any significant change in response to the calculation task. STAI-A-State scores increased significantly only in response to 90 dB(A) noise exposure, while both the indices showed significant increases under the effects of both noise exposure and the calculation task. The sensitivity of the rate of increase in plasma cyclic AMP caused by noise exposure plus the calculation task was higher than that of the rate of increase in scores on the A-State scale caused by this noise exposure/task combination. The physiological effect in human subjects of noise exposure became larger when a psychological stress (calculation task) was added.

Iwamoto, M.; Ishii, F.; Yoneda, J.; Morie, T.; Harada, N.

1995-10-01

49

'Stoffenmanager', a web-based control banding tool using an exposure process model.  

PubMed

In the scope of a Dutch programme to reinforce the working conditions policy on hazardous substances, an internet-based tool was developed to help small- and medium-sized companies to handle hazardous substances with more care. The heart of this tool, called the Stoffenmanager, is a risk banding scheme. It combines a hazard banding scheme similar to that of COSHH Essentials and an exposure banding scheme based on an exposure model originally presented by Cherrie et al. (1996) and further developed by Cherrie and Schneider (1999). The exposure model has been modified to allow non-expert users to understand and use the model. Exposure scores are calculated based on categorization of determinants of emission, transmission and immission. These exposure scores are assigned to exposure bands. The comparison of exposure bands and hazard bands leads to a risk band or priority band. Following the evaluation of the priority of tasks done with products, generic exposure control measures can be evaluated for their possibility to lower the risks. Relevant control measures can be put into an action plan and into workplace instruction cards. The tool has several other functionalities regarding registration and storage of products. The exposure model in the Stoffenmanager leads to exposure scores. These have been compared with measured exposure levels. The exposure scores correlated well with measured exposure levels. The development of the Stoffenmanager has facilitated a whole range of further developments of useful tools for small- and medium-sized enterprises. PMID:18587140

Marquart, Hans; Heussen, Henri; Le Feber, Maaike; Noy, Dook; Tielemans, Erik; Schinkel, Jody; West, John; Van Der Schaaf, Doeke

2008-08-01

50

Task-based assessment and optimization of digital breast tomosynthesis  

NASA Astrophysics Data System (ADS)

Digital breast tomosynthesis (DBT) is a new technology for breast cancer screening that promises to complement mammography or supersede it to become the standard for breast imaging. DBT involves taking multiple images in order to synthesize a new image that represents a slice through the breast volume---hence the term tomosynthesis. The primary advantage of this paradigm is that it can reduce the amount of overlapping anatomy in the data, leading to improved visualization of potentially-cancerous findings. The difficulty in DBT is quantifying the advantages of the technology and determining the optimal conditions for its clinical use. This dissertation describes a virtual trial framework for assessing and optimizing DBT technology for the specific task of detecting small, low-contrast masses in the breast. It addresses each component of the imaging chain to some degree, from the patients/phantoms to the imaging hardware to the model observers used to measure signal detectability. The main focus, however, is on quantifying tradeoffs between three key parameters that affect image quality: (1) scan angle, (2) number of projections, and (3) exposure. We show that in low-density breast phantoms, detectability generally increases with both scan angle and number of projections in the anatomical-variability-limited (high-exposure) regime. We also investigate how breast density affects the optimal DBT scan parameters. We show task-specific results that support using an adaptive paradigm in DBT, where the imaging system reconfigures itself in response to information about the patient's breast density. The virtual framework described in this dissertation provides a platform for further investigations of image quality in 3D breast imaging.

Young, Stefano

51

Automated Task-Based Synthesis and Optimization of Field Robots  

Microsoft Academic Search

We present Darwin2K, a widely-applicable, extensible software tool for synthesizing and optimizing robot configu- rations. The system uses an evolutionary optimization algo- rithm that is independent of task, metrics, and type of robot, enabling the system to address a wide range of synthesis problems. Darwin2K can synthesize fixed-base and mobile robots (including free-flying robots, mobile manipulators, modular robots, and multiple

Chris Leger; John Bares

1999-01-01

52

Interpersonal Attractiveness and Distribution of Task Relevant Information as Contributors to an Influence Base in Task Oriented Groups.  

ERIC Educational Resources Information Center

This study focused on the role played by two factors--interpersonal attractiveness of group members and pattern of distribution of task-relevant information--in forming an influence base in task-oriented discussion groups. For purposes of the study, members of discussion groups who were confederates in the study were assigned attitudinal…

Reinheimer, Robert Edward

53

Task-allocation algorithm for collaborative design based on negotiation mechanism  

Microsoft Academic Search

Aiming at the allocation problem of collaboration design task, an allocation algorithm of design tasks based on negotiation mechanism is proposed in this paper. Firstly, it presents the task bidding process based on negotiation mechanism. Tenders and bidders will complete design tasks allocation according to the negotiation to avoid some problems because of forcible assignment, such as excessive allocation, low-enthusiasm

Ying Wang; Yitai Xu; Xiaodong Zhang

2009-01-01

54

Task-based lens design, with application to digital mammography  

NASA Astrophysics Data System (ADS)

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 (DOGs). 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 the physics principles, and the main system component under study is the imaging lens that couples a fluorescent screen to a CCD detector. The SNR of the channelized Hotelling observer is used to quantify the detectability of the simulated lesion (signal) upon the simulated mammographic background. In this work, plots of channelized Hotelling SNR vs. signal location for various lens apertures, various working distances, and various focusing places are shown. 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.

Chen, Liying

55

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

PubMed

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. PMID:22316757

Potvin, Jim R

2012-01-01

56

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

PubMed Central

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

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

2014-01-01

57

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

ERIC Educational Resources Information Center

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…

McDonough, Kim; Chaikitmongkol, Wanpen

2007-01-01

58

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

ERIC Educational Resources Information Center

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,…

Revesz, Andrea

2011-01-01

59

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

ERIC Educational Resources Information Center

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…

Butler, Yuko Goto; Zeng, Wei

2014-01-01

60

A task-based quality control metric for digital mammography  

NASA Astrophysics Data System (ADS)

A reader study was conducted to tune the parameters of an observer model used to predict the detectability index (d??) 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 d?. The model was tuned by measuring d? of discs in a four-alternative forced choice reader study. For each disc diameter, d? 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 d?, with Pearson correlation coefficient of 0.96. Repeated measurements from separate images of the test phantom show an average coefficient of variation in d? 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 d? shows promise as a cross platform QC metric for digital mammography.

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

2014-11-01

61

Task-set switching under cue-based versus memory-based switching conditions in younger and older adults  

Microsoft Academic Search

Adult age differences in task switching and advance preparation were examined by comparing cue-based and memory-based switching conditions. Task switching was assessed by determining two types of costs that occur at the general (mixing costs) and specific (switching costs) level of switching. Advance preparation was investigated by varying the time interval until the next task (short, middle, very long). Results

Jutta Kray

2006-01-01

62

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

SciTech Connect

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.

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

2007-02-01

63

Occupational exposure to electric and magnetic fields during work tasks at 110 kV substations in the Tampere region.  

PubMed

The occupational exposure to electric and magnetic fields during various work tasks at seven 110 kV substations in Finland's Tampere region was studied. The aim was to investigate if the action values (10 kV/m for the E-field and 500 microT for the B-field) of the EU Directive 2004/40/EC were exceeded. Electric and magnetic fields were measured during the following work tasks: (1) walking or operating devices on the ground; (2) working from a service platform; (3) working around the power transformer on the ground or using a ladder; and (4) changing a bulb from a man hoist. In work task 2 "working from a service platform" the measured electric field (maximum value 16.6 kV/m) exceeded 10 kV/m in three cases. In the future it is important to study if the limit value (10 mA/m(2)) of Directive 2004/40/EC is exceeded at 110 kV substations. The occupational 500 microT action value of the magnetic flux density field (B-field) was not exceeded in any working situation. PMID:20077529

Korpinen, Leena H; Pääkkönen, Rauno J

2010-04-01

64

Occupational exposure to electric fields and induced currents associated with 400?kV substation tasks from different service platforms.  

PubMed

The aim of the study was to investigate the occupational exposure to electric fields, average current densities, and average total contact currents at 400?kV substation tasks from different service platforms (main transformer inspection, maintenance of operating device of disconnector, maintenance of operating device of circuit breaker). The average values are calculated over measured periods (about 2.5 min). In many work tasks, the maximum electric field strengths exceeded the action values proposed in the EU Directive 2004/40/EC, but the average electric fields (0.2-24.5 kV/m) were at least 40% lower than the maximum values. The average current densities were 0.1-2.3 mA/m² and the average total contact currents 2.0-143.2 µA, that is, clearly less than the limit values of the EU Directive. The average values of the currents in head and contact currents were 16-68% lower than the maximum values when we compared the average value from all cases in the same substation. In the future it is important to pay attention to the fact that the action and limit values of the EU Directive differ significantly. It is also important to take into account that generally, the workers' exposure to the electric fields, current densities, and total contact currents are obviously lower if we use the average values from a certain measured time period (e.g., 2.5 min) than in the case where exposure is defined with only the help of the maximum values. PMID:20925064

Korpinen, Leena H; Elovaara, Jarmo A; Kuisti, Harri A

2011-01-01

65

Effects of Acute or Chronic Ethanol Exposure during Adolescence on Behavioral Inhibition and Efficiency in a Modified Water Maze Task  

PubMed Central

Ethanol is well known to adversely affect frontal executive functioning, which continues to develop throughout adolescence and into young adulthood. This is also a developmental window in which ethanol is misused by a significant number of adolescents. We examined the effects of acute and chronic ethanol exposure during adolescence on behavioral inhibition and efficiency using a modified water maze task. During acquisition, rats were trained to find a stable visible platform onto which they could escape. During the test phase, the stable platform was converted to a visible floating platform (providing no escape) and a new hidden platform was added in the opposite quadrant. The hidden platform was the only means of escape during the test phase. In experiment 1, adolescent animals received ethanol (1.0g/kg) 30min before each session during the test phase. In experiment 2, adolescent animals received chronic intermittent ethanol (5.0g/kg) for 16 days (PND30 To PND46) prior to any training in the maze. At PND72, training was initiated in the same modified water maze task. Results from experiment 1 indicated that acute ethanol promoted behavioral disinhibition and inefficiency. Experiment 2 showed that chronic intermittent ethanol during adolescence appeared to have no lasting effect on behavioral disinhibition or new spatial learning during adulthood. However, chronic ethanol did promote behavioral inefficiency. In summary, results indicate that ethanol-induced promotion of perseverative behavior may contribute to the many adverse behavioral sequelae of alcohol intoxication in adolescents and young adults. Moreover, the long-term effect of adolescent chronic ethanol exposure on behavioral efficiency is similar to that observed after chronic exposure in humans. PMID:24147077

Acheson, Shawn K.; Bearison, Craig; Risher, M. Louise; Abdelwahab, Sabri H.; Wilson, Wilkie A.; Swartzwelder, H. Scott

2013-01-01

66

Early lead exposure effects on an auditory threshold task in the rhesus monkey (Macaca mulatta).  

PubMed

Behavioral thresholds to pure tones were obtained from adult rhesus monkeys that had been exposed to lead during early development and unexposed cohort controls. Thresholds were elevated (by 2-9 dB) for the previously lead exposed monkeys at all frequencies tested (125-8,000 Hz in octave steps). Although the magnitude and direction of the differences were similar to significant effects reported for children, the more difficult task and much smaller sample sizes in this study of monkeys may have precluded obtaining significant differences at the same magnitude of effects observed in children. Thresholds for one lead-exposed monkey were significantly elevated at midrange frequencies in agreement with electrophysiological results obtained in another study [Lasky, Maier, Snodgrass, Hecox, and Laughlin [1995] Neurotoxicology and Teratology, 17, 633-644]. Behavioral measurements during the threshold task indicated less engagement for lead exposed monkeys than for controls. In addition, the lead exposed monkeys completed testing at significantly fewer frequencies and were significantly more difficult to test than control monkeys by tester ratings. These results are consistent with reports concerning the behavior of lead exposed children. PMID:19145592

Laughlin, Nellie K; Luck, Melissa L; Lasky, Robert E

2009-04-01

67

Trayectorias: A New Model for Online Task-Based Learning  

ERIC Educational Resources Information Center

This paper discusses a framework for designing online tasks that capitalizes on the possibilities that the Internet and the Web offer for language learning. To present such a framework, we draw from constructivist theories (Brooks and Brooks, 1993) and their application to educational technology (Newby, Stepich, Lehman and Russell, 1996; Jonassen,…

Ros i Sole, Cristina; Mardomingo, Raquel

2004-01-01

68

Task Templates Based on Misconception Research. CSE Report 646.  

ERIC Educational Resources Information Center

Researchers spend much time and effort developing measures, including measures of students? conceptual knowledge. In an effort to make such assessments easier to design, the Principled Assessment Designs for Inquiry (PADI) project has developed a framework for designing tasks and to illustrate that its use has ?reverse engineered? several …

Cromley, Jennifer G.; Mislevy, Robert J.

2004-01-01

69

Enhancing Automaticity through Task-Based Language Learning  

ERIC Educational Resources Information Center

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 more…

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

2007-01-01

70

UMTS Base Station-like Exposure, Well-Being, and Cognitive Performance  

PubMed Central

Background Radio-frequency electromagnetic fields (RF EMF) of mobile communication systems are widespread in the living environment, yet their effects on humans are uncertain despite a growing body of literature. Objectives We investigated the influence of a Universal Mobile Telecommunications System (UMTS) base station-like signal on well-being and cognitive performance in subjects with and without self-reported sensitivity to RF EMF. Methods We performed a controlled exposure experiment (45 min at an electric field strength of 0, 1, or 10 V/m, incident with a polarization of 45° from the left back side of the subject, weekly intervals) in a randomized, double-blind crossover design. A total of 117 healthy subjects (33 self-reported sensitive, 84 nonsensitive subjects) participated in the study. We assessed well-being, perceived field strength, and cognitive performance with questionnaires and cognitive tasks and conducted statistical analyses using linear mixed models. Organ-specific and brain tissue–specific dosimetry including uncertainty and variation analysis was performed. Results In both groups, well-being and perceived field strength were not associated with actual exposure levels. We observed no consistent condition-induced changes in cognitive performance except for two marginal effects. At 10 V/m we observed a slight effect on speed in one of six tasks in the sensitive subjects and an effect on accuracy in another task in nonsensitive subjects. Both effects disappeared after multiple end point adjustment. Conclusions In contrast to a recent Dutch study, we could not confirm a short-term effect of UMTS base station-like exposure on well-being. The reported effects on brain functioning were marginal and may have occurred by chance. Peak spatial absorption in brain tissue was considerably smaller than during use of a mobile phone. No conclusions can be drawn regarding short-term effects of cell phone exposure or the effects of long-term base station-like exposure on human health. PMID:16882538

Regel, Sabine J.; Negovetic, Sonja; Roosli, Martin; Berdinas, Veronica; Schuderer, Jurgen; Huss, Anke; Lott, Urs; Kuster, Niels; Achermann, Peter

2006-01-01

71

Reduced Task-Resource Assignment Graph based Static scheduling for grid workflow application  

Microsoft Academic Search

The dynamic and heterogeneous nature of grid resources is a great challenge to static scheduling strategies of dependent tasks. Based on the full consideration of dynamics and heterogeneity of grid resources, this paper proposes a reduced task-resource assignment graph based scheduling model and a performance oriented (re)scheduling algorithm is implemented using immune genetic algorithm. The experimentation shows that compared with

Hao Xianwen; Dai Yu; Zhang Bin; Chen Tingwei

2008-01-01

72

Combination of Task Description Strategies and Case Base Properties for Meta-Learning  

E-print Network

Combination of Task Description Strategies and Case Base Properties for Meta-Learning Christian K, not only for meta- learning but also to gain insight in this learning task. The paper evaluates the performance of a recent method for assessing quality standards for case bases when used for a supervised meta-learning

Bohanec, Marko

73

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

ERIC Educational Resources Information Center

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

Pyun, Danielle Ooyoung

2013-01-01

74

FIREFIGHTING 1. Exposure Data 1.1 Activities and tasks of firefighters  

E-print Network

The terms ‘firefighting ’ and ‘firefighters ’ are broad and encompass several types of fire scenarios such as municipal, wildland, industrial, aviation, military, and oil wells. Some municipal firefighters may be permanently assigned to tasks other than fighting fires, including fire scene investigation (i.e. the investigation of suspected criminal fires started by arsonists), hazardous material response, building safety inspections, or technical and administrative support. These individuals may or may not have experience fighting fires, and may or may not be working for municipal fire departments. In addition, municipal firefighters are increasingly being called upon for emergency medical response. Finally, the term “firemen ” may refer either to firefighters or to individuals who operate and maintain equipment for power generation (e.g. steam boilers), heating, ventilation, humidity control, refrigeration, and air conditioning. Workers in this latter category are also referred to as “stationary engineers ” or “stationary firemen ” (Decoufle et al., 1977), and are not considered in this monograph. There are two more or less distinct phases in municipal structural firefighting: knockdown and overhaul. During knockdown, firefighters control and extinguish the fire.

unknown authors

75

FIREFIGHTING FIREFIGHTING 1. Exposure Data 1.1 Activities and tasks of firefighters  

E-print Network

The terms ‘firefighting ’ and ‘firefighters ’ are broad and encompass several types of fire scenarios such as municipal, wildland, industrial, aviation, military, and oil wells. Some municipal firefighters may be permanently assigned to tasks other than fighting fires, including fire scene investigation (i.e. the investigation of suspected criminal fires started by arsonists), hazardous material response, building safety inspections, or technical and administrative support. These individuals may or may not have experience fighting fires, and may or may not be working for municipal fire departments. In addition, municipal firefighters are increasingly being called upon for emergency medical response. Finally, the term “firemen ” may refer either to firefighters or to individuals who operate and maintain equipment for power generation (e.g. steam boilers), heating, ventilation, humidity control, refrigeration, and air conditioning. Workers in this latter category are also referred to as “stationary engineers ” or “stationary firemen ” (Decoufle et al., 1977), and are not considered in this monograph. There are two more or less distinct phases in municipal structural firefighting: knockdown and overhaul. During knockdown, firefighters control and extinguish the fire.

unknown authors

76

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

PubMed Central

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

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

2014-01-01

77

Establishing aerosol exposure predictive models based on vibration measurements  

Microsoft Academic Search

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., ax, ay, and az) was measured from the hand tool.

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

2010-01-01

78

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

PubMed

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. PMID:24131133

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

79

Linguistic characteristics of ESL writing in task-based e-mail activities  

Microsoft Academic Search

This study investigated the efficacy of integrating task-based e-mail activities into a process-oriented ESL writing class. In particular, it examined the linguistic characteristics of 132 pieces of e-mail writing by ESL students in tasks that differed in terms of purpose, audience interaction and task structure. The analysis focused on the linguistic features of the students' e-mail writing at different levels,

Yili Li

2000-01-01

80

Task-based Self-Organization in Large Smart Spaces: Issues and Challenges 1  

Microsoft Academic Search

Smart spaces of the future will consist of a large number of computing devices intelligently communicating with each other to perform various day-to-day tasks. Self- organization of these devices to form task-oriented clusters is a necessity as these devices grow in number. Given a rich collection of mobile tetherless smart-devices, it is important to investigate schemes for task-based self-organization so

P. Basu; T. D. C. Little

1999-01-01

81

Development of Prospective Memory: Tasks Based on the Prefrontal-Lobe Model  

Microsoft Academic Search

This study investigated the development of prospective memory using tasks based on the prefrontal-lobe model. Three groups each of 30 children, adolescents, and young adults were compared on prospective-memory performance using ongoing tasks with two levels of cognitive demand (low and high), and two levels of importance (unstressed and stressed) of remembering prospective cues. The Self-Ordered Pointing Task (SOPT), Stroop

Heather Ward; David Shum; Lynne McKinlay; Simone Baker-Tweney; Geoff Wallace

2005-01-01

82

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

NASA Astrophysics Data System (ADS)

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 might actually be achieved at resolutions lower than the maximum available in current exposure cat models and as yet undefined. Further, dominance of a few models, associated consensus results, and preeminence of exposure concepts can lead to the subjective interpretation of inaccuracies in exposure distribution/attribution that can result in biased model results. More extreme solutions have resulted in input exposure data being calibrated with model results in order to achieve pre-determined and self-fulfilling outcomes. These outcomes could be avoided by allowing realistic uncertainty ranges rather than restricting interpretation of risk results to misleading "consensus nutshell" numbers. The paper concludes by considering new concepts in the use of exposure models and describes potential scenarios for the future use of input data in cat models.

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

2010-05-01

83

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

PubMed Central

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

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

84

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

PubMed

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

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

2013-08-01

85

A General Information Quality Based Approach for Satisfying Sensor Constraints in Multirobot Tasks  

E-print Network

A General Information Quality Based Approach for Satisfying Sensor Constraints in Multirobot Tasks Yu Zhang and Lynne E. Parker Proc. of IEEE International Conference on Robotics and Automation-coupled multirobot tasks (MT) through coalitions of heterogeneous robots. However, several issues remain unad

Parker, Lynne E.

86

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

ERIC Educational Resources Information Center

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…

McFarland, Craig P.; Glisky, Elizabeth L.

2009-01-01

87

Performance of visually guided tasks using simulated prosthetic vision and saliency-based cues  

NASA Astrophysics Data System (ADS)

Objective. The objective of this paper is to evaluate the benefits provided by a saliency-based cueing algorithm to normally sighted volunteers performing mobility and search tasks using simulated prosthetic vision. Approach. Human subjects performed mobility and search tasks using simulated prosthetic vision. A saliency algorithm based on primate vision was used to detect regions of interest (ROI) in an image. Subjects were cued to look toward the directions of these ROI using visual cues superimposed on the simulated prosthetic vision. Mobility tasks required the subjects to navigate through a corridor, avoid obstacles and locate a target at the end of the course. Two search task experiments involved finding objects on a tabletop under different conditions. Subjects were required to perform tasks with and without any help from cues. Results. Head movements, time to task completion and number of errors were all significantly reduced in search tasks when subjects used the cueing algorithm. For the mobility task, head movements and number of contacts with objects were significantly reduced when subjects used cues, whereas time was significantly reduced when no cues were used. The most significant benefit from cues appears to be in search tasks and when navigating unfamiliar environments. Significance. The results from the study show that visually impaired people and retinal prosthesis implantees may benefit from computer vision algorithms that detect important objects in their environment, particularly when they are in a new environment.

Parikh, N.; Itti, L.; Humayun, M.; Weiland, J.

2013-04-01

88

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

PubMed

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. PMID:24045850

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

2014-05-01

89

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

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

90

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

NASA Astrophysics Data System (ADS)

Digital breast tomosynthesis (DBT) is a novel x-ray imaging technique that provides 3D structural information of the breast. In contrast to 2D mammography, DBT minimizes tissue overlap potentially improving cancer detection and reducing number of unnecessary recalls. The addition of a contrast agent to DBT and mammography for lesion enhancement has the benefit of providing functional information of a lesion, as lesion contrast uptake and washout patterns may help differentiate between benign and malignant tumors. This study used a task-based method to determine the optimal imaging approach by analyzing six imaging paradigms in terms of their ability to resolve iodine at a given dose: contrast enhanced mammography and tomosynthesis, temporal subtraction mammography and tomosynthesis, and dual energy subtraction mammography and tomosynthesis. Imaging performance was characterized using a detectability index d', derived from the system task transfer function (TTF), an imaging task, iodine contrast, and the noise power spectrum (NPS). The task modeled a 5 mm 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. In general, higher dose gave higher d', but for the lowest iodine concentration and lowest dose, dual energy subtraction tomosynthesis and temporal subtraction tomosynthesis demonstrated the highest performance.

Ikejimba, Lynda; Kiarashi, Nooshin; Lin, Yuan; Chen, Baiyu; Ghate, Sujata V.; Zerhouni, Moustafa; Samei, Ehsan; Lo, Joseph Y.

2012-03-01

91

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

NASA Technical Reports Server (NTRS)

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.

1987-01-01

92

A field-based versus a protocol-based approach for adaptive task assignment  

Microsoft Academic Search

Task assignment in multi-agent systems is a complex coordination problem, in particular in systems that are subject to dynamic and changing operating conditions. To enable agents to deal with dynamism and change, adaptive task assignment approaches are needed. In this paper, we study two approaches for adaptive task assignment that are characteristic for two classical families of task assignment approaches.

Danny Weyns; Nelis Boucké; Tom Holvoet

2008-01-01

93

Ecological Problem-Based Learning: An Environmental Consulting Task  

ERIC Educational Resources Information Center

Problem-based learning is becoming a popular and effective approach in Science, as it touted as an effective way to promote active learning and encourage students to develop life long learning skills. The problem-based learning could easily be adapted to the high school level and used as long-term project for a biology laboratory.

Tessier, Jack T.

2004-01-01

94

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

ERIC Educational Resources Information Center

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…

Wolfersberger, Mark

2013-01-01

95

Task Based Automatic Examination System for Sequenced Test  

Microsoft Academic Search

Computer greatly influences our educational environment. Over the last years, automatic computer examination systems have been widely used for computer-based tests. But these systems are based on traditional question-answer examination style which is not fit for the sequenced test. The sequenced test should consider the context of the examinee, e.g. the order of questions or the permissions of the examinee,

Song Luo; Jianbin Hu; Zhong Chen

2009-01-01

96

Efficient models for base station antennas for human exposure assessment  

Microsoft Academic Search

Two simple and accurate models for base-station (BS) panel antennas are proposed for human-exposure assessment. Panel antennas comprise an antenna array with low coupling between its unit cells. The proposed model is based on the superposition of shifted radiating field contributions in amplitude and phase of a unit cell of the panel antenna. In the first model, the electric field

Zwi Altman; Brigitte Begasse; Christian Dale; Andrzej Karwowski; Joe Wiart; Man-Fai Wong; Laroussi Gattoufi

2002-01-01

97

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

PubMed

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 equipment that optimize risk reduction without undue impact on a mission. PMID:10706522

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

2000-03-01

98

Characterising the Quality of Online Task-Based Application Tutorials  

E-print Network

previous work, I characterize the quality of text- and image-based Photoshop tutorials available to users . . . . . . . . . . . . . . . 5 2.1.1 Differences Between Media . . . . . . . . . . . . . . . . . . . . 6 2.1.2 Designing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 4 A Study of Online Photoshop Tutorial Quality 27 4.1 Tutorial Sources

99

Realization of the Table Tennis Task Based on Virtual Targets  

Microsoft Academic Search

This paper describes how a table tennis robot with a fiat paddle coordinates its movement in order to achieve efficient strokes for any given ball. We pro- pose a method of generating stroke movement based on virtual targets that means the point at which the ball should be struck and the paddle velocity just be- fore hitting the ball. These

Fumio Miyazaki; Takeuchi Michiya Matsushima; Michiya Matsushima; Takamichi Kusano; Takaaki Hashimoto

2002-01-01

100

Brief exposure to an enriched environment improves performance on the Morris water task and increases hippocampal cytosolic protein kinase C activity in young rats.  

PubMed

This study was designed to determine whether brief exposure to an enriched environment around the time of weaning would affect learning and memory processes in young rats. In addition, this study sought to determine if experience in an enriched environment would alter hippocampal protein kinase C (PKC) which is thought to be a possible neural substrate that underlies learning and memory processes. Animals were either reared in an enriched environment or standard laboratory cages starting at 15 days old. After 6 (21 days old) or 12 (27 days old) days subjects were either tested in the Morris water task, or had the hippocampus removed for biochemical analysis of PKC activity. Morris water task results showed that compared to laboratory reared controls, the performance of subjects reared in the enriched environment for 12 days, but not 6 days, was improved. In addition, 12 days of exposure to the enriched environment, but not 6 days, produced more cytosolic hippocampal PKC activity. The particulate fraction appeared not to be affected by rearing in the enriched environment. Brief exposure to an enriched environment around weaning, therefore, both improved Morris water task performance and increased hippocampal PKC activity. These outcomes suggest that performance in the Morris water task and hippocampal PKC may be functionally related. PMID:1472287

Paylor, R; Morrison, S K; Rudy, J W; Waltrip, L T; Wehner, J M

1992-11-30

101

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

PubMed

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. PMID:25152925

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

2014-01-01

102

Behavior-based multi-robot collaboration for autonomous construction tasks  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

103

Multiple Robots Tasks Allocation: An Auction-Based Approach Using Dynamic-Domain RRT  

NASA Astrophysics Data System (ADS)

Consider a 2D environment, in which multiple robots, initially at random configurations, can move. We propose an auction-based method for the allocation of tasks to these robots. We consider tasks as some points in the environment. The environment is occupied with static obstacles, but other moving robots can be considered as dynamic obstacles and may prevent a robot from reaching its goal. So rebidding may be necessary at definite times.

Nazif, Ali Nasri; Iranmanesh, Ehsan; Mohades, Ali

104

Accuracy-Based Phonological Awareness Tasks: Are They Reliable, Efficient, and Sensitive to Growth?  

Microsoft Academic Search

This two-experiment study examined the efficiency and sensitivity of five accuracy-based phonological awareness tasks (i.e., Rhyme-Providing, Sound-Providing, Blending, Segmentation, and Deletion) for monitoring the development of these skills in kindergarten and Grade 1 students. The first experiment examined responses to different numbers and types of items included in each phonological awareness task for their correspondence to responses obtained from a

Sandra M. Chafouleas; Brian K. Martens

2002-01-01

105

Reward-based transfer from bottom-up to top-down search tasks.  

PubMed

Recent evidence has suggested that reward modulates bottom-up and top-down attentional selection and that this effect persists within the same task even when reward is no longer offered. It remains unclear whether reward effects transfer across tasks, especially those engaging different modes of attention. We directly investigated whether reward-based contingency learned in a bottom-up search task was transferred to a subsequent top-down search task, and probed the nature of the transfer mechanism. Results showed that a reward-related benefit established in a pop-out-search task was transferred to a conjunction-search task, increasing participants' efficiency at searching for targets previously associated with a higher level of reward. Reward history influenced search efficiency by enhancing both target salience and distractor filtering, depending on whether the target and distractors shared a critical feature. These results provide evidence for reward-based transfer between different modes of attention and strongly suggest that an integrated priority map based on reward information guides both top-down and bottom-up attention. PMID:24335604

Lee, Jeongmi; Shomstein, Sarah

2014-02-01

106

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

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

107

Establishing aerosol exposure predictive models based on vibration measurements.  

PubMed

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. PMID:20153113

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

2010-06-15

108

Biomonitoring Hexamethylene Diisocyanate (HDI) Exposure Based on Serum Levels of HDI-Specific IgG  

PubMed Central

Objectives: Isocyanate chemicals essential for polyurethane production are widely used industrially, and are increasingly found in consumer products. Asthma and other adverse health effects of isocyanates are well-documented and exposure surveillance is crucial to disease prevention. Hexamethylene diisocyanate (HDI)-specific serum immunoglobulin G (IgG) was evaluated as an exposure biomarker among workers at a US Air Force Air Logistics Center, which includes a large aircraft maintenance facility. Methods: HDI-specific IgG (HDI-IgG) titers in serum samples (n = 74) were measured using an enzyme-linked immunosorbent assay based upon the biuret form of HDI conjugated to human albumin. Information on personal protective equipment (PPE), work location/tasks, smoking, asthma history, basic demographics, and HDI skin exposure was obtained through questionnaire. Results: HDI-specific serum IgG levels were elevated in n = 17 (23%) of the workers studied. The prevalence and/or end-titer of the HDI-IgG was significantly (P < 0.05) associated with specific job titles, self-reported skin exposure, night-shift work, and respirator use, but not atopy, asthma, or other demographic information. The highest titers were localized to specific worksites (C-130 painting), while other worksites (generator painting) had no or few workers with detectable HDI-IgG. Conclusions: HDI-specific immune responses (IgG) provide a practical biomarker to aid in exposure surveillance and ongoing industrial hygiene efforts. The strategy may supplement current air sampling approaches, which do not assess exposures via skin, or variability in PPE use or effectiveness. The approach may also be applicable to evaluating isocyanate exposures in other settings, and may extend to other chemical allergens. PMID:22449630

Wisnewski, Adam V.; Stowe, Meredith H.; Nerlinger, Abby; Opare-addo, Paul; Decamp, David; Kleinsmith, Christopher R.; Redlich, Carrie A.

2012-01-01

109

Study of Internal Exposure Based on the ICRP Publication 30.  

National Technical Information Service (NTIS)

A computer program to calculate an internal exposure has been developed. It is based on the ICRP Publication 30. The influences on the committed dose equivalent by the factors such as an activity median aerodynamic diameter(AMAD) of a radioactive aerosol,...

T. Matsunaga, A. Kasai

1983-01-01

110

A decision analytic approach to exposure-based chemical prioritization.  

PubMed

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

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

2013-01-01

111

A Decision Analytic Approach to Exposure-Based Chemical Prioritization  

PubMed Central

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

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

2013-01-01

112

Analyses of several realistic exposure scenarios near cellular base stations  

Microsoft Academic Search

This paper contains the results of computer simulations performed for several realistic scenarios of electromagnetic (EM) field evaluation near the cellular base station (CBS) and some analysis of obtained results. The motivation of this study is exposure assessment of EM energy on biological objects. There are scenarios of field distribution indoors, near the hill, obstacle like a wall and finally

R. Zaridze; D. Kakulia; G. Kajaia; D. Mazmanov; L. Manukyan; N. Jejelava; T. Gogua

2006-01-01

113

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

PubMed

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. PMID:22217591

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

2012-02-01

114

Performance Evaluation of Gesture-based 2D and 3D Pointing Tasks  

E-print Network

to comparatively evaluate the performance of gesture-based 2D and 3D pointing tasks. In both of them, a Wiimote trajectory. Keywords: Fitts' law, 3D pointing, Gesture User Interface, Wiimote, 1 Introduction Nowadays, low in the domain of device-based gesture user interaction. Nintendo's Wii Remote Control (known as Wiimote

Kouroupetroglou, Georgios

115

Clustering-Based Simultaneous Task and Voltage Scheduling for NoC Systems  

E-print Network

-efficiency improvement. In this work, we propose a simultaneous task and voltage scheduling algorithm for energy minimization in NoC based designs. The energy-latency tradeoff is handled by Lagrangian relaxation. The core algorithm is a clustering based approach which...

Yang, Yu

2011-08-08

116

Fast HDR Image Generation Technique Based on Exposure Blending  

Microsoft Academic Search

\\u000a In the proposed work a method for generating HDR images based on exposure blending is described. Using three differently exposed\\u000a images a single image with recovered details in shadows and highlights is generated. Input images are analyzed to locate over\\u000a and underexposed regions based on pixels intensity. Local contrast of input images is also considered in order to generate\\u000a the

Andrey Vavilin; Kaushik Deb; Kang-Hyun Jo

2010-01-01

117

Cumulative lead exposure in community-dwelling adults and fine motor function: comparing standard and novel tasks in the VA Normative Aging Study  

PubMed Central

Background and Aims Lead exposure in children and occupationally-exposed adults has been associated with reduced visuomotor and fine motor function. However, associations in environmentally-exposed adults remain relatively unexplored. To address this, we examined the association between cumulative lead exposure—as measured by lead in bone—and performance on the Grooved Pegboard (GP) manual dexterity task, as well as on handwriting tasks using a novel assessment approach, among men in the VA Normative Aging Study (NAS). Methods GP testing was done with 362 NAS participants, and handwriting assessment with 328, who also had tibia and patella lead measurements made with K-X-Ray Fluorescence (KXRF). GP scores were time (sec) to complete the task with the dominant hand. The handwriting assessment approach assessed the production of signature and cursive lowercase l and m letter samples. Signature and lm task scores reflect consistency in repeated trials. We used linear regression to estimate associations and 95% confidence intervals (CI) with adjustment for age, smoking, education, income and computer experience. A backward elimination algorithm was used in the subset with both GP and handwriting assessment to identify variables predictive of each outcome. Results The mean (SD) participant age was 69.1 (7.2) years; mean patella and tibia concentrations were 25.0 (20.7) ?g/g and 19.2 (14.6) ?g/g, respectively. In multivariable-adjusted analyses, GP performance was associated with tibia (? per 15 ?g/g bone = 4.66, 95% CI: 1.73, 7.58, p=0.002) and patella (? per 20 ?g/g = 3.93, 95% CI: 1.11, 6.76, p = 0.006). In multivariable adjusted models of handwriting production, only the lm-pattern task showed a significant association with tibia (? per 15 ?g/g bone = 1.27, 95% CI: 0.24, 2.29, p = 0.015), such that lm pattern production was more stable with increasing lead exposure. GP and handwriting scores were differentially sensitive to education, smoking, computer experience, financial stability, income and alcohol consumption. Conclusions Long-term cumulative environmental lead exposure was associated with deficits in GP performance, but not handwriting production. Higher lead appeared to be associated with greater consistency on the lm task. Lead sensitivity differences could suggest that lead affects neural processing speed rather than motor function per se, or could result from distinct brain areas involved in the execution of different motor tasks. PMID:23370289

Grashow, Rachel; Spiro, Avron; Taylor, Kathryn M.; Newton, Kimberly; Shrairman, Ruth; Landau, Alexander; Sparrow, David; Hu, Howard; Weisskopf, Marc

2013-01-01

118

Effects of acceptance-based coping on task performance and subjective stress.  

PubMed

This paper examines the interactive effects of acceptance-based coping and job control on task performance, subjective stress, and perceived control. Forty-eight undergraduate and graduate students first participated in brief educational programs based on either acceptance or control coping strategies. They then participated in a 30-min high workload task under either high or low job control conditions. The results demonstrated a significant interactive effect of acceptance-based coping and job control on perceived control and task performance. No such effect was found for subjective stress. We conclude that to improve employees' perceived control and job performance, there should be an increase not only in job control through work redesign, but also in psychological acceptance. PMID:21074000

Kishita, Naoko; Shimada, Hironori

2011-03-01

119

Chronic intermittent ethanol exposure during adolescence reduces the effect of ethanol challenge on hippocampal allopregnanolone levels and Morris water maze task performance  

Microsoft Academic Search

Chronic intermittent ethanol exposure (CIEE) in adolescent rats has been shown to produce long-lasting hypnotic, metabolic, and functional tolerance. Recently, it has been hypothesized that allopregnanolone mediates some effects of ethanol, including ethanol-induced impairments in the performance of the Morris Water Maze Task (MWMT). The current studies explore the relationship between cortical and hippocampal allopregnanolone levels and ethanol-induced impairments in

Janelle M. Silvers; Sayaka Tokunaga; Guy Mittleman; Todd O'Buckley; A. Leslie Morrow; Douglas B. Matthews

2006-01-01

120

An augmented reality (AR)-based vocational task prompting system for people with cognitive impairments.  

PubMed

This study assessed the possibility of training three people with cognitive impairments using an augmented reality (AR)-based task prompting system. Using AR technology, the system provided picture cues, identified incorrect task steps on the fly, and helped users 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. PMID:23880030

Chang, Yao-Jen; Kang, Ya-Shu; Huang, Po-Chiao

2013-10-01

121

Characterization of exposure-dependent eigenvalue drift using Monte Carlo based nuclear fuel management  

NASA Astrophysics Data System (ADS)

The ability to accurately predict the multiplication factor (keff) of a nuclear reactor core as a function of exposure continues to be an elusive task for core designers despite decades of advances in computational methods. The difference between a predicted eigenvalue (target) and the actual eigenvalue at critical reactor conditions is herein referred to as the "eigenvalue drift." This dissertation studies exposure-dependent eigenvalue drift using MCNP-based fuel management analysis of the ORNL High Flux Isotope Reactor core. Spatial-dependent burnup is evaluated using the MONTEBURNS and ALEPH codes to link MCNP to ORIGEN to help analyze the behavior of keff as a function of fuel exposure. Understanding the exposure-dependent eigenvalue drift of a nuclear reactor is of particular relevance when trying to predict the impact of major design changes upon fuel cycle behavior and length. In this research, the design of an advanced HFIR core with a fuel loading of 12 kg of 235U is contrasted against the current loading of 9.4 kg. The goal of applying exposure dependent eigenvalue characterization is to produce a more accurate prediction of the fuel cycle length than prior analysis techniques, and to improve our understanding of the reactivity behavior of the core throughout the cycle. This investigation predicted a fuel cycle length of 40 days, representing a 50% increase in the cycle length in response to a 25% increase in fuel loading. The average burnup increased by about 48 MWd/kg U and it was confirmed that the excess reactivity can be controlled with the present design and arrangement of control elements throughout the core's life. Another major design change studied was the effect of installing an internal beryllium reflector upon cycle length. Exposure dependent eigenvalue predictions indicate that the actual benefit could be twice as large as that originally assessed via beginning-of-life (BOL) analyses.

Xoubi, Ned

2005-12-01

122

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

PubMed

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. PMID:10723014

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

2000-04-01

123

What's special about task in dystonia? A voxel-based morphometry and diffusion weighted imaging study.  

PubMed

Numerous brain imaging studies have demonstrated structural changes in the basal ganglia, thalamus, sensorimotor cortex, and cerebellum across different forms of primary dystonia. However, our understanding of brain abnormalities contributing to the clinically well-described phenomenon of task specificity in dystonia remained limited. We used high-resolution magnetic resonance imaging (MRI) with voxel-based morphometry and diffusion weighted imaging with tract-based spatial statistics of fractional anisotropy to examine gray and white matter organization in two task-specific dystonia forms, writer's cramp and laryngeal dystonia, and two non-task-specific dystonia forms, cervical dystonia and blepharospasm. A direct comparison between both dystonia forms indicated that characteristic gray matter volumetric changes in task-specific dystonia involve the brain regions responsible for sensorimotor control during writing and speaking, such as primary somatosensory cortex, middle frontal gyrus, superior/inferior temporal gyrus, middle/posterior cingulate cortex, and occipital cortex as well as the striatum and cerebellum (lobules VI-VIIa). These gray matter changes were accompanied by white matter abnormalities in the premotor cortex, middle/inferior frontal gyrus, genu of the corpus callosum, anterior limb/genu of the internal capsule, and putamen. Conversely, gray matter volumetric changes in the non-task-specific group were limited to the left cerebellum (lobule VIIa) only, whereas white matter alterations were found to underlie the primary sensorimotor cortex, inferior parietal lobule, and middle cingulate gyrus. Distinct microstructural patterns in task-specific and non-task-specific dystonias may represent neuroimaging markers and provide evidence that these two dystonia subclasses likely follow divergent pathophysiological mechanisms precipitated by different triggers. PMID:24925463

Ramdhani, Ritesh A; Kumar, Veena; Velickovic, Miodrag; Frucht, Steven J; Tagliati, Michele; Simonyan, Kristina

2014-08-01

124

Memory in the Small: An Application to Provide Task-Based Organizational Memory for a Scientific Community  

E-print Network

Memory in the Small: An Application to Provide Task-Based Organizational Memory for a Scientific of organizational memory must exist embedded within the organizational processes and tasks. This paper argues that "memory-in-the small," memory utilized in the performance of an organizational task, can serve

Ackerman, Mark S.

125

Brain Computer Interface based robotic rehabilitation with online modification of task speed.  

PubMed

We present a systematic approach that enables online modification/adaptation of robot assisted rehabilitation exercises by continuously monitoring intention levels of patients utilizing an electroencephalogram (EEG) based Brain-Computer Interface (BCI). In particular, we use Linear Discriminant Analysis (LDA) to classify event-related synchronization (ERS) and desynchronization (ERD) patterns associated with motor imagery; however, instead of providing a binary classification output, we utilize posterior probabilities extracted from LDA classifier as the continuous-valued outputs to control a rehabilitation robot. Passive velocity field control (PVFC) is used as the underlying robot controller to map instantaneous levels of motor imagery during the movement to the speed of contour following tasks. In other words, PVFC changes the speed of contour following tasks with respect to intention levels of motor imagery. PVFC also allows decoupling of the task and the speed of the task from each other, and ensures coupled stability of the overall robot patient system. The proposed framework is implemented on AssistOn-Mobile--a series elastic actuator based on a holonomic mobile platform, and feasibility studies with healthy volunteers have been conducted test effectiveness of the proposed approach. Giving patients online control over the speed of the task, the proposed approach ensures active involvement of patients throughout exercise routines and has the potential to increase the efficacy of robot assisted therapies. PMID:24187241

Sarac, Mine; Koyas, Ela; Erdogan, Ahmetcan; Cetin, Mujdat; Patoglu, Volkan

2013-06-01

126

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

ERIC Educational Resources Information Center

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…

Jee, Min Jung

2010-01-01

127

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

ERIC Educational Resources Information Center

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…

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

128

Talking, Tuning in and Noticing: Exploring the Benefits of Output in Task-Based Peer Interaction  

ERIC Educational Resources Information Center

This study examines whether the process of interacting in a second language, versus observing others interact, may differentially affect learner's awareness of language. This study involved 26 university students of intermediate-level French. Two experimental groups, Interactors and Observers, engaged in three sessions of dyadic task-based

Philp, Jenefer; Iwashita, Noriko

2013-01-01

129

Fuzzy Logic as a Basis for Reusing Task-Based Specifications  

E-print Network

Fuzzy Logic as a Basis for Reusing Task-Based Specifications Lein F. Lai, Jonathan Lee match and fuzzy logic, and a paraphraser to serve as an explanation mechanism for the retrieval, and 3 reusing compo- nents that have been proven correct to enhance reliability and thus for ease

Lee, Jonathan

130

Energy-aware Scheduling for Frame-based Tasks on Heterogeneous Multiprocessor Platforms  

E-print Network

lead to high energy consumption. oDVFS allows processors to adjust othe supply voltage or othe balanced partition really result in less energy consumption? #12;Motivational Example 2012-9-13 9ICPP 2012Energy-aware Scheduling for Frame-based Tasks on Heterogeneous Multiprocessor Platforms Dawei Li

Wu, Jie

131

The Development and Implementation of Task-Based Writing Performance Assessment for Japanese Learners of English  

ERIC Educational Resources Information Center

The main purpose of this research is 1) to establish a framework for the test development and the constructs of writing performance test, 2) to implement a developed writing performance assessment, and 3) to examine the degree of reliability and validity of the assessment tasks and rating scales. Construct-based processing approach to testing…

Sugita, Yoshihito

2009-01-01

132

Accuracy-Based Learning Classier Systems: Models, Analysis and Applications to Classication Tasks  

Microsoft Academic Search

Recently, Learning Classier Systems (LCS) and particularly XCS have arisen as promising methods for classication tasks and data mining. This paper investigates two models of accuracy-based learning classier systems on different types of classi- cation problems. Departing from XCS, we analyze the evolution of a complete action map as a knowledge representation. We propose an alternative, UCS, which evolves a

Ester Bernad; Josep M. Garrell-Guiu

2003-01-01

133

Vision based behavior verification system of humanoid robot for daily environment tasks  

E-print Network

, there exist developmental learning approach without given models [1], it seems to take long time to develop it-okada@jsk.t.u-tokyo.ac.jp Abstract-- This paper describes integrated/intelligent hu- manoid robot system for daily-life environment tasks. We have realized complex behaviors of a humanoid robot in daily- life environment based on motion

Yamamoto, Hirosuke

134

RICE UNIVERSITY Visual Cues to Reduce Error in Computer-based Routine Procedural Tasks  

E-print Network

RICE UNIVERSITY Visual Cues to Reduce Error in Computer-based Routine Procedural Tasks by Phillip H David M. Lane, Associate Professor Psychology Kenneth R. Laughery, Emeritus Professor Psychology #12 chair and mentor, Mike Byrne. I am also thoroughly obliged to my other committee members David Lane

Byrne, Mike

135

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

ERIC Educational Resources Information Center

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…

Libbon, Stephanie

2004-01-01

136

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

ERIC Educational Resources Information Center

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…

East, Martin

2012-01-01

137

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

ERIC Educational Resources Information Center

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…

Batstone, Rob

2012-01-01

138

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

ERIC Educational Resources Information Center

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…

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

2011-01-01

139

Diverse-Rate Based Dual Energy Aware Efficiency Task Scheduling Scheme in WSNs  

Microsoft Academic Search

It is important to increase the wireless sensor networks (WSNs) lifetime and the ability of energy conservation, due to its limited energy resource, while meeting the constraints of applications. In this paper, we concern the protocol and OS task schedule perspective to enhance the performance of WSNs. Firstly we propose a diverse-rate based upon pre-schedule schedule to further decrease collisions

Wei Wei; Xiao-ying Wang; Bin Zhou; Ang Gao; He Xin

2009-01-01

140

Trust-based Multi-Objective Optimization for Node-to-Task Assignment in Coalition Networks  

E-print Network

to select members based on risk derived from trust assessment of nodes. We validate the performance of our networks in terms of potential risk, context- dependency, dynamicity, and reliability. In this work assignment algorithm for a scenario where tasks are dynamic, with different arrival times and deadlines. We

Chen, Ing-Ray

141

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

ERIC Educational Resources Information Center

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…

Hu, Ran

2013-01-01

142

Experimental Analysis of Task-based Energy Consumption in Cloud Computing Systems  

E-print Network

Experimental Analysis of Task-based Energy Consumption in Cloud Computing Systems Feifei Chen, John}@swin.edu.au ABSTRACT Cloud computing delivers IT solutions as a utility to users. One consequence of this model. We have developed an energy consumption model for cloud computing systems. To operationalise

Schneider, Jean-Guy

143

Negotiation over tasks in hybrid human-agent teams for simulation-based training  

Microsoft Academic Search

The effectiveness of simulation-based training for individual tasks -- such as piloting skills -- is well established, but its use for team training raises challenging technical issues. Ideally, human users could gain valuable leadership experience by interacting with synthetic teammates in realistic and potentially stressful scenarios. However, creating human-like teammates that can support flexible, natural interactions with humans and other

David R. Traum; Jeff Rickel; Jonathan Gratch; Stacy Marsella

2003-01-01

144

Exploring Adaptive Dialogue Based on a Robot's Awareness of Human Gaze and Task Progress  

E-print Network

and Principles]: User/Machine Systems ­ Human factors, Software psychology. H.5.2 [Information Interfaces, Experimentation, Human Factors, Theory. Keywords Human-robot interaction, human-robot dialogue, adaptive dialogueExploring Adaptive Dialogue Based on a Robot's Awareness of Human Gaze and Task Progress Cristen

Fussell, Susan R.

145

Retrospective Time Perception of a Long Task: Using Music to Distinguish between Attention-based and Memory-based Models  

Microsoft Academic Search

Attention-based models and memory-based models propose different outcomes of retrospective time perception of a long task. The effects of music on perceived time duration was used to determine which model best explained the results. In an independent design, 48 adults were randomly assigned to a silent condition or one of three music conditions. In all four conditions participants completed a

James Brooks

2012-01-01

146

Behavior-Based Multi-Robot Collaboration for Autonomous Construction Tasks  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

147

Algorithm Design of CPCI Backboard's Interrupts Management Based on VxWorks' Multi-Tasks  

NASA Astrophysics Data System (ADS)

This paper begins with a brief introduction of the embedded real-time operating system VxWorks and CompactPCI standard, then gives the programming interfaces of Peripheral Controller Interface (PCI) configuring, interrupts handling and multi-tasks programming interface under VxWorks, and then emphasis is placed on the software frameworks of CPCI interrupt management based on multi-tasks. This method is sound in design and easy to adapt, ensures that all possible interrupts are handled in time, which makes it suitable for data acquisition systems with multi-channels, a high data rate, and hard real-time high energy physics.

Cheng, Jingyuan; An, Qi; Yang, Junfeng

2006-09-01

148

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

SciTech Connect

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) telluride detectors.

Bornefalk, Hans [Department of Physics, Royal Institute of Technology, SE-106 91 Stockholm (Sweden)

2011-11-15

149

Performance Monitoring and Analysis of Task-Based OpenMP  

PubMed Central

OpenMP, a typical shared memory programming paradigm, has been extensively applied in high performance computing community due to the popularity of multicore architectures in recent years. The most significant feature of the OpenMP 3.0 specification is the introduction of the task constructs to express parallelism at a much finer level of detail. This feature, however, has posed new challenges for performance monitoring and analysis. In particular, task creation is separated from its execution, causing the traditional monitoring methods to be ineffective. This paper presents a mechanism to monitor task-based OpenMP programs with interposition and proposes two demonstration graphs for performance analysis as well. The results of two experiments are discussed to evaluate the overhead of monitoring mechanism and to verify the effects of demonstration graphs using the BOTS benchmarks. PMID:24204946

Ding, Yi; Hu, Kai; Wu, Kai; Zhao, Zhenlong

2013-01-01

150

Quadrotor UAV Control for Vision-based Moving Target Tracking Task  

NASA Astrophysics Data System (ADS)

The problem of stand-off tracking of a moving target using a quadrotor unmanned aerial vehicle (UAV) based on vision-sensing is investigated. A PID (Proportional-Integral-Derivative) controller is implemented for attitude stabilization of the quadrotor. An LQG-based (Linear-Quadratic-Gaussian) control law is designed and implemented for position control of the quadrotor for a moving target tracking task. A novel vision-based estimation algorithm is developed, enabling estimation of quadrotor's position, altitude and yaw relative to the target based on limited information about the target. Two image processing algorithms are implemented and compared for the task of feature detection and feature tracking in a series of images. Image processing algorithms are integrated with quadrotor control and experiments are performed to validate proposed control and estimation approaches.

Bohdanov, Denys

151

Statistical-Based Response-Time Analysis of Systems with Execution Dependencies between Tasks  

Microsoft Academic Search

This paper presents a novel statistical-based approach to Worst-Case Response-Time (WCRT) analysis of complex real-time system models. These system models have been tailored to capture intricate execution dependencies between tasks, inspired by real industrial control systems. The proposed WCRT estimation algorithm is based on Extreme Value Theory (EVT) and produces both WCRT estimates together with a probability of being exceeded.

Yue Lu; Thomas Nolte; Johan Kraft; Christer Norström

2010-01-01

152

Is direction position? Position and direction-based correspondence effects in tasks with moving stimuli  

Microsoft Academic Search

Five experiments were carried out to test whether (task-irrelevant) motion information provided by a stimulus changing its position over time would affect manual left–right responses. So far, some studies reported direction-based Simon effects whereas others did not. In Experiment 1a, a reliable direction-based effect occurred, which was not modulated by the response mode—that is, by whether participants responded by pressing

Simone Bosbach; Wolfgang Prinz; Dirk Kerzel

2005-01-01

153

Nanotechnology-Based Electrochemical Sensors for Biomonitoring Chemical Exposures  

PubMed Central

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

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

2009-01-01

154

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

NASA Technical Reports Server (NTRS)

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.

Bloom, Ben; Mcgrath, Debra; Sanborn, Jim

1989-01-01

155

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

PubMed Central

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

Baus, Oliver; Bouchard, Stephane

2014-01-01

156

Forecasting exposure to volcanic ash based on ash dispersion modeling  

NASA Astrophysics Data System (ADS)

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 locations of research facilities or military bases can be assessed for susceptibility to hazardous and unhealthy concentrations of ash and other volcanic gases.

Peterson, Rorik A.; Dean, Ken G.

2008-03-01

157

Object Retrieval in the 1st Year of Life: Learning Effects of Task Exposure and Box Transparency  

ERIC Educational Resources Information Center

Before 12 months of age, infants have difficulties coordinating and sequencing their movements to retrieve an object concealed in a box. This study examined (a) whether young infants can discover effective retrieval solutions and consolidate movement coordination earlier if exposed regularly to such a task and (b) whether different environments,…

Bojczyk, Kathryn E.; Corbetta, Daniela

2004-01-01

158

From task-based to competency-based : A typology and process supporting a critical HRM transition  

Microsoft Academic Search

Purpose – Organizational effectiveness today depends largely on the ability to activate, share and transform the intellectual capital of the company into sustainable and difficult-to-imitate competitive advantage. This paper seeks to develop a competency typology that integrates previous definitions and frameworks from the literature and to propose a methodology for identifying competencies to aid the transition from a task-based to

Klas Eric Soderquist; Alexandros Papalexandris; George Ioannou; Gregory Prastacos

2010-01-01

159

U.S. Department of Justice: Task Force for Faith-based & Community Initiatives  

NSDL National Science Digital Library

On January 29, 2001, President George W. Bush issued two executive orders related to faith-based and community organizations. The first established a base of operations within the White House for such initiatives, and the second established centers within various cabinet- level departments, including the Department of Justice (DOJ). As the latter's website notes, "The Task Force's purpose is to promote good works by neighbors, particularly in the areas of juvenile delinquency, prisoners and their families, victims of crime, domestic violence, and drug addiction/treatment/prevention." Visitors to the site can learn about funding opportunities administered by the DOJ and also read some of its publications, such as "Moving Beyond the Walls: Faith and Justice Partnerships Working for High Risk Youth". Interested parties may also want to look at the Task Force's FAQ section and sign up to receive email updates.

160

Fisher kernel based task boundary retrieval in laparoscopic database with single video query.  

PubMed

As minimally invasive surgery becomes increasingly popular, the volume of recorded laparoscopic videos will increase rapidly. Invaluable information for teaching, assistance during difficult cases, and quality evaluation can be accessed from these videos through a video search engine. Typically, video search engines give a list of the most relevant videos pertaining to a keyword. However, instead of a whole video, one is often only interested in a fraction of the video (e.g. intestine stitching in bypass surgeries). In addition, video search requires semantic tags, yet the large amount of data typically generated hinders the feasibility of manual annotation. To tackle these problems, we propose a coarse-to-fine video indexing approach that looks for the time boundaries of a task in a laparoscopic video based on a video snippet query. We combine our search approach with the Fisher kernel (FK) encoding and show that similarity measures on this encoding are better suited for this problem than traditional similarities, such as dynamic time warping (DTW). Despite visual challenges, such as the presence of smoke, motion blur, and lens impurity, our approach performs very well in finding 3 tasks in 49 bypass videos, 1 task in 23 hernia videos, and also 1 cross-surgery task between 49 bypass and 7 sleeve gastrectomy videos. PMID:25320826

Twinanda, Andru Putra; De Mathelin, Michel; Padoy, Nicolas

2014-01-01

161

A velocity observer design for tracking task-based motions of unicycle type mobile robots  

NASA Astrophysics Data System (ADS)

The paper presents a design of a nonlinear velocity observer and its application within a model-based tracking control strategy for tracking task-based motions of unicycle type mobile robots. The strategy is the model reference tracking control strategy for programmed motion and it enables switching between controllers employed in it to improve a tracking precision as well as switching between coordinates used for modeling based on a type of a nonholonomic system. The strategy benefits by adding the velocity observer to its architecture due to the reduction of a number of measurements needed for feedback tracking.

Jarzebowska, El?bieta

2011-05-01

162

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

ERIC Educational Resources Information Center

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

Gan, Zhengdong

2012-01-01

163

An Agent-Based Simulation for Investigating the Impact of Stereotypes on Task-Oriented Group Formation  

E-print Network

An Agent-Based Simulation for Investigating the Impact of Stereotypes on Task-Oriented Group of stereotypes on group formation. In our simulation, stereotypes are based on observable features, learned from stereotypes affect the agents' willingness or ability to complete tasks, the long-term modifications

Sukthankar, Gita Reese

164

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

ERIC Educational Resources Information Center

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…

Ahmadian, Mohammad Javad

2012-01-01

165

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

NASA Astrophysics Data System (ADS)

A number of recent studies have demonstrated that near-infrared spectroscopy (NIRS) is a promising neuroimaging modality for brain-computer interfaces (BCIs). So far, most NIRS-based BCI studies have focused on enhancing the accuracy of the classification of different mental tasks. In the present study, we evaluated the performances of a variety of mental task combinations in order to determine the mental task pairs that are best suited for customized NIRS-based BCIs. To this end, we recorded event-related hemodynamic responses while seven participants performed eight different mental tasks. Classification accuracies were then estimated for all possible pairs of the eight mental tasks (C=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.

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

2014-07-01

166

An approach to situational market segmentation on on-line newspapers based on current tasks  

Microsoft Academic Search

We discuss how a task-based situational market segmentation may be applied to on-line newspapers, distinguishing between fact finding, information gathering and browsing. During a period of four weeks we had 41 users keep a diary and recorded their surfing behavior on different on-line newspapers. The results of a Naive Bayes classification with feature selection indicate that content-related attributes such as

Anne Gutschmidt

2010-01-01

167

Intelligent Agents for Web-based Tasks: An Advice-Taking Approach  

Microsoft Academic Search

We present and evaluate an implemented system with which to rapidly and easily build intelli- gent software agents for Web-based tasks. Our design is centered around two basic functions: ScoreThisLink and ScoreThisPage .I f given highly accurate such functions, standard heuristic search would lead to ecient retrieval of useful information. Our approach allows users to tailor our system's behavior by

Jude Shavlik; Tina Eliassi-Rad

1998-01-01

168

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

Microsoft Academic Search

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

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

2008-01-01

169

Modelling framework for assessment of dietary exposure to added flavouring substances within the FACET (Flavours, Additives, and Food Contact Material Exposure Task) project.  

PubMed

This paper provides a model to assess dietary exposure to flavouring substances intentionally added to food. The purpose is to describe the approaches currently available and their scientific basis. The proposed exposure model for flavouring substances envisages three different levels of refinement: basic, intermediate and refined. At the two first levels, the model may be applied to all 2543 substances actually in use in Europe, while the refined level has been applied to 41 target flavouring substances selected within the FACET project. The refined level entails the use of the probability of addition of the flavouring substance added to the food and of correction factors related to losses owing to the processing of a food. PMID:23639587

Mistura, Lorenza; Sette, Stefania; O'Mahony, Cian; Engel, Karl-Heinz; Mehegan, John; Leclercq, Catherine

2013-08-01

170

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

171

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

PubMed

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. PMID:25080373

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

2014-10-01

172

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

Microsoft Academic Search

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

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

2008-01-01

173

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

ERIC Educational Resources Information Center

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,…

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

2007-01-01

174

Development of a personal computer-based secondary task procedure as a surrogate for a driving simulator  

E-print Network

-based study procedure (PCSP) with secondary task loading for use in human factors laboratory experiments in lieu of a driving simulator to test reading time and understanding of traffic control devices such as changeable message sign (CMS) messages. Using... Microsoft ? Visual C# ? , a PCSP was developed where subjects were shown CMS messages while simultaneously deactivating randomly displayed buttons in an on-screen control panel which served as a secondary loading task. The subject secondary task...

Schrock, Steven Dale

2009-05-15

175

Exploring Fine-Grained Task-based Execution on Multi-GPU Systems  

SciTech Connect

Many-core Graphics Processing Units (GPUs) have been utilized as the computation engine in many scientific fields due to the high peak performance, cost effectiveness, and the availability of user friendly programming environments, e.g., NVIDIA CUDA. However, the conventional data parallel GPU programming paradigm cannot satisfactorily address issues such as load balancing and GPU resource utilization due to the irregular and unbalanced workload patterns exhibited in some applications. In this paper, we explore the design space of task-based solutions for multi-GPU systems. By employing finer-grained tasks than what is supported in the current CUDA, and allowing task sharing, our solutions enable dynamic load balancing. We evaluate our solutions with a Molecular Dynamics application with different atom distributions (from uniform distribution to highly non-uniform distribution). Experimental results obtained on a 4-GPU system show that, for non-uniform distributed systems, our solutions achieve excellent speedup, and significant performance improvement over other solutions based on the standard CUDA APIs.

Chen, Long; Villa, Oreste; Gao, Guang R.

2011-09-25

176

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

PubMed

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. PMID:24929345

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

2014-09-01

177

Elementary Students' Learning of Materials Science Practices Through Instruction Based on Engineering Design Tasks  

NASA Astrophysics Data System (ADS)

Materials science, which entails the practices of selecting, testing, and characterizing materials, is an important discipline within the study of matter. This paper examines how third grade students' materials science performance changes over the course of instruction based on an engineering design challenge. We conducted a case study of nine students who participated in engineering design-based science instruction with the goal of constructing a stable, quiet, thermally comfortable model house. The learning outcome of materials science practices was assessed by clinical interviews conducted before and after the instruction, and the learning process was assessed by students' workbooks completed during the instruction. The interviews included two materials selection tasks for designing a sturdy stepstool and an insulated pet habitat. Results indicate that: (1) students significantly improved on both materials selection tasks, (2) their gains were significantly positively associated with the degree of completion of their workbooks, and (3) students who were highly engaged with the workbook's reflective record-keeping tasks showed the greatest improvement on the interviews. These findings suggest the important role workbooks can play in facilitating elementary students' learning of science through authentic activity such as engineering design.

Wendell, Kristen Bethke; Lee, Hee-Sun

2010-12-01

178

Development of lead source-specific exposure standards based on aggregate exposure assessment: Bayesian inversion from biomonitoring information to multipathway exposure.  

PubMed

Exposure of children to lead is of great concern, and the exposure standards for different media are important for protecting public safety. However, these media-specific standards often fail to ensure the safety of children even when environmental lead levels are lower than the quality standards since humans are often exposed to lead via multiple pathways. To establish exposure standards to protect children from hazards associated with exposure to lead, an analytical tool for assessing aggregate exposure to lead based on Bayesian hierarchical model was developed, and then was used to update the external lead exposure of diet, paint, soil, air and drinking water using the blood lead levels in Chinese children aged 1-6 years. On the basis of updated external exposure, the source allocations for diet, paint, soil, air, and drinking water in China were 65.80 ± 7.92%, 16.98 ± 7.88%, 13.65 ± 5.05%, 3.36 ± 1.75%, and 0.20 ± 0.14%, respectively. Based on the estimated source allocations, the exposure standards were evaluated to be 0.2 ?g/m(3), 24.25 mg/kg, 0.027 ?g/L, 0.051 ?g/mg, 0.042 ?g/mg, 38.02 ?g/mg for air, soil, water, grains, vegetables, and paint, respectively. Since the standards setting procedure was based on the multipathway aggregate exposure assessment of lead, the newly proposed exposure standards should ensure the safety of children. PMID:22142206

Dong, Zhaomin; Hu, Jianying

2012-01-17

179

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

PubMed Central

The present experiment 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 RT 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. PMID:19739913

Touron, Dayna R.; Hertzog, Christopher

2009-01-01

180

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

NASA Astrophysics Data System (ADS)

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 GEO, too. Simulations using ESA’s Program for Radar and Optical Observation Forecasting (PROOF) in the version 2005 and a GEO reference population extracted from DISCOS revealed that the proposed pointing scenario provides low phase angles together with low angular velocities of the objects crossing the field-of-view. Radiometric simulations show that the optimal exposure time is 1-2 s, and that spherical objects in GEO with a diameter of below 1 m can be detected. The GEO population can be covered under proper illumination nearly completely, but seasonal drops of the coverage are possible. Subsequent observations of objects are on average at least every 1.5 days, not exceeding 3 days at maximum. A single observation arc spans 3° to 5° on average. Using a simulation environment that connects PROOF to AIUB’s program system CelMech we verify the consistency of the initial orbit determination for five selected test objects on subsequent days as a function of realistic astrometric noise levels. The initial orbit determination is possible. We define requirements for a correlator process essential for catalogue build-up and maintenance. Each single observation should provide an astrometric accuracy of at least 1”-1.5” so that the initially determined orbits are consistent within a few hundred kilometres for the semi-major axis, 0.01 for the eccentricity, and 0.1° for the inclination.

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

2011-03-01

181

Effects of occupational exposure - is there a link between exposure based on an occupational questionnaire and semen quality?  

PubMed

Several studies have suggested that human semen quality has declined over past decades and some have associated decline with occupational exposures. Many studies have been conducted in occupational settings, where exposure to occupational pollutants is intense. Our objective was to examine the association between exposure to occupational factors based on an occupational exposure questionnaire, and semen quality parameters (sperm concentration, motility, sperm morphology) and sperm chromatin structure. The study population consisted of 336 men who were attending an infertility clinic for diagnostic purposes and who had a normal semen concentration of ?15?mln/ml according to WHO criteria. All participants were interviewed and provided a semen sample. Additionally, a detailed questionnaire about the exposure to occupational factors was performed among the study participants. The results of the study suggest that occupational factors may affect semen quality. The exposure to noise during work was associated with decreased motility and increased DNA damage (p?=?0.005 and p?=?0.02, respectively). Exposure to polyvinyl chloride (PVC) decreased sperm concentration and motility (p?=?0.02 and p?=?0.03, respectively). Whereas exposure to high temperatures and sitting for more than 6 hours during work was positively associated with DNA fragmentation index (DFI) (p?=?0.03 and p?=?0.001, respectively). After applying the correction for multiple comparisons only the exposure to noise and sitting ?6 hours during work was associated with poorer semen quality (decreased motility and increased DFI, respectively). This study showed associations between self-reported occupational exposures and impaired semen parameters. The occupational exposure questionnaire may be useful in clinical practice for patients and physicians to identify the work factors associated with poorer semen quality. PMID:24702586

Jurewicz, Joanna; Radwan, Micha?; Sobala, Wojciech; Radwan, Pawe?; Bochenek, Micha?; Hanke, Wojciech

2014-08-01

182

The Cruelest Cure? Ethical Issues in the Implementation of Exposure-Based Treatments  

ERIC Educational Resources Information Center

Numerous studies have provided supportive evidence for the efficacy of exposure-based treatments for many psychological disorders. However, surprisingly few therapists use exposure therapy in the clinical setting. Although the limited use of exposure-based treatments may be partially attributable to a shortage of suitably trained therapists,…

Olatunji, Bunmi O.; Deacon, Brett J.; Abramowitz, Jonathan S.

2009-01-01

183

A matrix modular neural network based on task decomposition with subspace division by adaptive affinity propagation clustering  

Microsoft Academic Search

In this paper, a matrix modular neural network (MMNN) based on task decomposition with subspace division by adaptive affinity propagation clustering is developed to solve classification tasks. First, we propose an adaptive version to affinity propagation clustering, which is adopted to divide each class subspace into several clusters. By these divisions of class spaces, a classification problem can be decomposed

Zhong-Qiu Zhao; Jun Gao; Herve Glotin; Xindong Wu

2010-01-01

184

ASET: a Multi-Agent Planning Language with Nondeterministic Durative Tasks for BDD-Based Fault Tolerant Planning  

E-print Network

language called ASynchronous Evolving Tasks (ASET). The main con- tribution of ASET is a novel explicit is to expose the representational power of the language by providing intuitive and explicit ways to stateASET: a Multi-Agent Planning Language with Nondeterministic Durative Tasks for BDD-Based Fault

Veloso, Manuela M.

185

On the Relationship Between Effort Toward an Ongoing Task and Cue Detection in Event-Based Prospective Memory  

Microsoft Academic Search

In recent theories of event-based prospective memory, researchers have debated what degree of resources are necessary to identify a cue as related to a previously established intention. In order to simulate natural variations in attention, the authors manipulated effort toward an ongoing cognitive task in which intention-related cues were embedded in 3 experiments. High effort toward the ongoing task resulted

Richard L. Marsh; Jason L. Hicks; Gabriel I. Cook

2005-01-01

186

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

PubMed Central

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???1.3 for the imaging tasks considered. The results suggested kVp selection in the range of ?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., ?0.1–0.2 mm pixel size (and a sharp reconstruction filter) optimal for high-frequency tasks (bone detail) compared to ?0.4 mm pixel size (and a smooth reconstruction filter) for low-frequency (soft-tissue) tasks. This result suggests a specific protocol for 1?×?1 (full-resolution) projection data acquisition followed by full-resolution reconstruction with a sharp filter for high-frequency tasks along with 2?×?2 binning reconstruction with a smooth filter for low-frequency tasks. The analysis guided selection of specific source and detector components implemented on the proposed scanner. The analysis also quantified the potential benefits and points of diminishing return in focal spot size, reduced electronic noise, finer detector pixels, and low-dose limits of detectability. Theoretical results agreed quantitatively with the measured NPS and qualitatively with evaluation of cadaver images by a musculoskeletal radiologist. Conclusions: A fairly comprehensive model for 3D imaging performance in cone-beam CT combines factors of quantum noise, system geometry, anatomical background, and imaging task. The analysis provided a valuable, quantitative guide to design, optimization, and technique selection for a musculoskeletal extremities imaging system under development. PMID:21992379

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

2011-01-01

187

Base-rate Respect by Intuition: Approximating Rational Choices in Base-rate Tasks with Multiple Cues  

Microsoft Academic Search

Although intuitive-automatic processes sometimes lead to systematic biases in judgment and choice, in many situations especially this kind of processes enables people to approximate rational choices. In complex base-rate tasks with repeated outcome feedback we observed choices which were in line with the Bayes’ solution in 86% of the cases and which were made within a relatively short time (i.e.,

Andreas Glöckner; Stephan Dickert

2008-01-01

188

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

ERIC Educational Resources Information Center

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…

Gardner, Joel; Jeon, Tae

2010-01-01

189

Patient-based radiographic exposure factor selection: a systematic review  

PubMed Central

Introduction 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. Methods 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. Results 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. Conclusion 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.

Ching, William; Robinson, John; McEntee, Mark

2014-01-01

190

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

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

191

Characterization of exposure-dependent eigenvalue drift using Monte Carlo based nuclear fuel management  

Microsoft Academic Search

The ability to accurately predict the multiplication factor (keff) of a nuclear reactor core as a function of exposure continues to be an elusive task for core designers despite decades of advances in computational methods. The difference between a predicted eigenvalue (target) and the actual eigenvalue at critical reactor conditions is herein referred to as the \\

Ned Xoubi

2005-01-01

192

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

PubMed Central

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

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

2013-01-01

193

Acute exposure to power-frequency magnetic fields has no effect on the acquisition of a spatial learning task by adult male mice  

SciTech Connect

A series of four experiments was performed to determine whether acute exposure to a range of 50 Hz magnetic fields had any effect on a learning task in adult male CD1 mice. A radial-arm maze placed within the bore of an electromagnetic was used to assess spatial discrimination learning for food reward. Subjects were reduced to 85% of their free-feeding weight and were placed in the maze for up to 15 minutes each day for 10 days. Performance of the task was measured by using maximum likelihood techniques to calculate the probability that an animal would not reenter any given arm of the maze. Experimental subjects were exposed to a vertical, 50 Hz sinusoidal magnetic field at 5 {micro}T, 50 {micro}T, 0.5 mT, or 5.0 mT (rms). Control subjects were exposed only to a background time-varying field of less than 50 nT and the ambient static field of about 40 {micro}T. The variation in the applied magnetic field was less than 5% except at the ends of the arms, where is approached 10%. It was found that all eight groups of subjects (n = 10 in all cases) showed similar increases in performance with testing, and the acquisition curve for each group of experimental subjects was not significantly different from that of their control group (P > 0.05 in all cases). It was concluded that exposure had no effect on learning at any flux density. This result is contrary to the findings of a number of preliminary studies, although other studies have reported that magnetic fields do not affect spatial learning in adult male rodents. It is possible that differences between experimental conditions might explain some of this apparent discrepancy.

Sienkiewicz, Z.J.; Haylock, R.G.E.; Saunders, R.D. [National Radiological Protection Board, Chilton (United Kingdom)] [National Radiological Protection Board, Chilton (United Kingdom)

1996-12-01

194

The effects of exposure to traumatic stressors on inhibitory control in police officers: a dense electrode array study using a Go/NoGo continuous performance task.  

PubMed

Exposure to psychologically stressful and traumatic experiences and the requirement of heightened attention to environmental stimuli are common in police work. Police officers are at increased risk for stress-related disorders such as Post-Traumatic Stress Disorder (PTSD). Traumatic experiences can result in changes to brain structure and function associated with attention and cognitive control processes (such as response inhibition). Despite the significance that these cognitive functions may have on job performance in police officers, few studies have examined the effects of exposure to traumatic events on top-down cognitive control functions in police. In the present study, a dense electrode array system was used to examined the N2 and P3 components of the event-related potential (ERP) during a Go/NoGo continuous performance task (Go/NoGo CPT) in trauma-exposed police officers who did not meet criteria for a current diagnosis of PTSD and in non-trauma exposed civilian controls. Amplitude and latency were obtained to Go, NoGo, and non-target trials. The major between-group findings were for P3 amplitude. There were no group effects for N2. Both groups had an enhanced fronto-central P3 amplitude to NoGo compared to Go trials. However, police had greater P3 amplitude compared to controls for all trial types (Go, NoGo, non-target). PTSD symptom scores in police officers were positively correlated with fronto-central NoGo P3 amplitude, but not with posterior NoGo amplitude. This study provides evidence of heightened attention and/or arousal in police officers as indicated by the generally greater P3 amplitude in police compared to controls during a task requiring sustained attention and inhibitory control. Greater PTSD symptom severity in trauma-exposed individuals may affect frontal cognitive control systems related to response inhibition. PMID:23528305

Covey, Thomas J; Shucard, Janet L; Violanti, John M; Lee, Jeff; Shucard, David W

2013-03-01

195

Studying hemispheric lateralization during a Stroop task through near-infrared spectroscopy-based connectivity.  

PubMed

ABSTRACT. 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. PMID:24862561

Zhang, Lei; Sun, Jinyan; Sun, Bailei; Luo, Qingming; Gong, Hui

2014-05-01

196

Studying hemispheric lateralization during a Stroop task through near-infrared spectroscopy-based connectivity  

NASA Astrophysics Data System (ADS)

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.

Zhang, Lei; Sun, Jinyan; Sun, Bailei; Luo, Qingming; Gong, Hui

2014-05-01

197

Prospective and retrospective time estimates of children: a comparison based on ecological tasks.  

PubMed

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

Bisson, Nicolas; Tobin, Simon; Grondin, Simon

2012-01-01

198

The software V&V tasks for a safety-critical software based protection system in nuclear power plants  

Microsoft Academic Search

This paper introduces the software life-cycle based V&V (verification and validation) tasks for the KNICS (Korea nuclear instrumentation and control system) project. The objectives of the V&V tasks are mainly to develop the programmable logic controller (PLQ for safety-critical instrumentation and control (I&C) systems, and then to apply the PLC to developing the prototype of the safety-critical software based digital

S. W. Cheon; G. Y. Park; K. H. Cha; J. S. Lee; K. C. Kwon

2005-01-01

199

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

Microsoft Academic Search

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 assessment context. An in-depth analysis of oral performance on two different

Zhengdong Gan

2012-01-01

200

Developing Respondent-Based MultiMedia Measures of Exposure to Sexual Content  

Microsoft Academic Search

Despite interest in media effects on sexual behavior, there is no single method for assessing exposure to sexual content in media. This paper discusses the development of sexual content exposure measures based on adolescent respondents' sexual content ratings of titles in television, music, magazines, and video games. We assessed the construct and criterion validity of these exposure measures by examining

Amy Bleakley; Martin Fishbein; Michal Hennessy; Amy Jordan; Ariel Chernin; Robin Stevens

2008-01-01

201

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...

202

Metaheuristic Based Scheduling Meta-Tasks in Distributed Heterogeneous Computing Systems  

PubMed Central

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

Izakian, Hesam; Abraham, Ajith; Snasel, Vaclav

2009-01-01

203

Imaging Tasks Scheduling for High-Altitude Airship in Emergency Condition Based on Energy-Aware Strategy  

PubMed Central

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

Zhimeng, Li; Chuan, He; Dishan, Qiu; Jin, Liu; Manhao, Ma

2013-01-01

204

Supernumerary Robotic Limbs : task planning, execution, and prediction-based coordination with the human wearer  

E-print Network

Full automation of repetitive and/or specialized tasks has become a preferred means to meet the needs of manufacturing industries. However, some tasks cannot be fully automated due to their complexity or the nature of the ...

Llorens-Bonilla, Baldin Adolfo

2013-01-01

205

Sequence learning under dual-task conditions: alternatives to a resource-based account  

Microsoft Academic Search

In two experiments with the serial reaction-time task, participants were presented with deterministic or probabilistic sequences under single- or dual-task conditions. Experiment 1 showed that learning of a probabilistic structure was not impaired over a first session by performing a counting task, but that such an interference arose over a second session, when the knowledge was tested under single-task conditions. In

Luis Jiménez; Gustavo A. Vázquez

2005-01-01

206

Complexity, Accuracy, Fluency and Lexis in Task-Based Performance: A Synthesis of the Ealing Research  

ERIC Educational Resources Information Center

This chapter will present a research synthesis of a series of studies, termed here the Ealing research. The studies use the same general framework to conceptualise tasks and task performance, enabling easier comparability. The different studies, although each is self-contained, build into a wider picture of task performance. The major point of…

Skehan, Peter; Foster, Pauline

2012-01-01

207

Classifying real and imaginary finger press tasks on a P300-based brain-computer interface.  

PubMed

Brain computer interfaces based on P300 and sensory-motor rhythms are widely studied and recent advances show some interest in the combination of the two. In this paper, typical P300 paradigm is modified by adding animation guide of the finger press as a stimulus and by using different response strategies (silent counting and actual/imaginary left or right index finger press following the animation). Both P300 potentials and sensory-motor rhythms are directly exploited and discussed. Classification results showed that even under very demanding conditions, which was, 200 ms inter-stimulus interval of the P300 stimuli and actual/imaginary finger press once per 1.6s, the paradigm can evoke both P300 potentials and sensory-motor rhythms simultaneously. Actual finger press increased single trial P300 selection accuracy of different subjects by 5-29.5% compared with silent counting; imaginary finger press did not increase the P300 selection accuracy apparently for most subjects except the two who were very poor at counting task. This showed by using different interface design and adopting certain mental response strategies, the 'BCI illiteracy' may be cured. Also imaginary task had good performance of left versus right classification (with the best subject reached 81.1% of accuracy), which is an additional information that can be used to improve system performance. PMID:22255792

Zhang, Jicai; Chen, Weidong; Gu, Yanlei; Wu, Bian; Qi, Yu; Zheng, Xiaoxiang

2011-01-01

208

Adaptation of a clustered lumpy background model for task-based image quality assessment in x-ray phase-contrast mammography  

PubMed Central

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. Conclusions: A method has been presented for the incorporation of structured breast background data into task-based numerical observer assessment of PCM images. The method adapts conventional background simulation techniques to the wavefield propagation physics necessary for PCM imaging. This method is demonstrated with a simple detection task. PMID:22320800

Zysk, Adam M.; Brankov, Jovan G.; Wernick, Miles N.; Anastasio, Mark A.

2012-01-01

209

A distributed computing environment with support for constraint-based task scheduling and scientific experimentation  

SciTech Connect

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.

Ahrens, J.P.; Shapiro, L.G.; Tanimoto, S.L. [Univ. of Washington, Seattle, WA (United States). Dept. of Computer Science and Engineering

1997-04-01

210

Lunar base scenario cost estimates: Lunar base systems study task 6.1  

NASA Technical Reports Server (NTRS)

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.

1988-01-01

211

Lunar base applications of superconductivity: Lunar base systems study task 3.4  

NASA Technical Reports Server (NTRS)

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.

1988-01-01

212

Abstract--Evidence-based medicine is a new direction in modern healthcare. Its task is to prevent, diagnose and medicate  

E-print Network

Abstract-- Evidence-based medicine is a new direction in modern healthcare. Its task is to prevent warehouse that facilitates evidence-based medicine is a reliable, powerful and user-friendly platform medicine. Keywords--data mining, data warehousing, decision-support systems, evidence-based medicine. I

213

Test of a vision-based autonomous space station robotic task  

NASA Astrophysics Data System (ADS)

An area of increasing interest in Al Robotics and Computer Vision is integrating techniques from these fields to the problem of controlling autonomous systems. Space-based systems such as NASA''s robotic assembly of Orbital Replacement Units (ORU''s) provide a complex realistic domain for this integration research. In this paper we report on current MITRE research in the use of situated control for autonomous robotic assembly of ORUs. A wrist-mounted camera is used to acquire the pose of ORU''s. An on-line control module uses the pose data to refine the on-going robot actions so that the planned task can be executed both safely and robustly. Experimental results on a Cincinnati Milacron T3 Industrial robot at Goddard Space Right Center (GSFC) Intelligent Robotic Laboratory will be included.

Castellano, Anthony R.; Hwang, Vincent S. S.; Stoney, William E.

1991-02-01

214

Subclass-based multi-task learning for Alzheimer's disease diagnosis.  

PubMed

In this work, we propose a novel subclass-based multi-task learning method for feature selection in computer-aided Alzheimer's Disease (AD) or Mild Cognitive Impairment (MCI) diagnosis. Unlike the previous methods that often assumed a unimodal data distribution, we take into account the underlying multipeak distribution of classes. The rationale for our approach is that it is highly likely for neuroimaging data to have multiple peaks or modes in distribution, e.g., mixture of Gaussians, due to the inter-subject variability. In this regard, we use a clustering method to discover the multipeak distributional characteristics and define subclasses based on the clustering results, in which each cluster covers a peak in the underlying multipeak distribution. Specifically, after performing clustering for each class, we encode the respective subclasses, i.e., clusters, with their unique codes. In encoding, we impose the subclasses of the same original class close to each other and those of different original classes distinct from each other. By setting the codes as new label vectors of our training samples, we formulate a multi-task learning problem in a ?2,1-penalized regression framework, through which we finally select features for classification. In our experimental results on the ADNI dataset, we validated the effectiveness of the proposed method by improving the classification accuracies by 1% (AD vs. Normal Control: NC), 3.25% (MCI vs. NC), 5.34% (AD vs. MCI), and 7.4% (MCI Converter: MCI-C vs. MCI Non-Converter: MCI-NC) compared to the competing single-task learning method. It is remarkable for the performance improvement in MCI-C vs. MCI-NC classification, which is the most important for early diagnosis and treatment. It is also noteworthy that with the strategy of modality-adaptive weights by means of a multi-kernel support vector machine, we maximally achieved the classification accuracies of 96.18% (AD vs. NC), 81.45% (MCI vs. NC), 73.21% (AD vs. MCI), and 74.04% (MCI-C vs. MCI-NC), respectively. PMID:25147522

Suk, Heung-Ii; Lee, Seong-Whan; Shen, Dinggang

2014-01-01

215

GLMdenoise: a fast, automated technique for denoising task-based fMRI data  

PubMed Central

In task-based functional magnetic resonance imaging (fMRI), researchers seek to measure fMRI signals related to a given task or condition. In many circumstances, measuring this signal of interest is limited by noise. In this study, we present GLMdenoise, a technique that improves signal-to-noise ratio (SNR) by entering noise regressors into a general linear model (GLM) analysis of fMRI data. The noise regressors are derived by conducting an initial model fit to determine voxels unrelated to the experimental paradigm, performing principal components analysis (PCA) on the time-series of these voxels, and using cross-validation to select the optimal number of principal components to use as noise regressors. Due to the use of data resampling, GLMdenoise requires and is best suited for datasets involving multiple runs (where conditions repeat across runs). We show that GLMdenoise consistently improves cross-validation accuracy of GLM estimates on a variety of event-related experimental datasets and is accompanied by substantial gains in SNR. To promote practical application of methods, we provide MATLAB code implementing GLMdenoise. Furthermore, to help compare GLMdenoise to other denoising methods, we present the Denoise Benchmark (DNB), a public database and architecture for evaluating denoising methods. The DNB consists of the datasets described in this paper, a code framework that enables automatic evaluation of a denoising method, and implementations of several denoising methods, including GLMdenoise, the use of motion parameters as noise regressors, ICA-based denoising, and RETROICOR/RVHRCOR. Using the DNB, we find that GLMdenoise performs best out of all of the denoising methods we tested. PMID:24381539

Kay, Kendrick N.; Rokem, Ariel; Winawer, Jonathan; Dougherty, Robert F.; Wandell, Brian A.

2013-01-01

216

The U.S. Preventive Services Task Force: An evidence-based prevention resource for nurse practitioners  

Microsoft Academic Search

Purpose: To describe the work of the U.S. Preventive Services Task Force and to encourage nurse practitioners (NPs) to use its evidence-based recommendations for clinical preventive services. Sources: Evidence reports, recommendation statements, and journal articles published under the auspices of the U.S. Preventive Services Task Force since its establishment in 1984. Conclusions: A core competency for NPs working in primary

Tricia Trinite; Carol Loveland-Cherry; Lucy Marion

2009-01-01

217

A tweaking principle for executive control: neuronal circuit mechanism for rule-based task switching and conflict resolution.  

PubMed

A hallmark of executive control is the brain's agility to shift between different tasks depending on the behavioral rule currently in play. In this work, we propose a "tweaking hypothesis" for task switching: a weak rule signal provides a small bias that is dramatically amplified by reverberating attractor dynamics in neural circuits for stimulus categorization and action selection, leading to an all-or-none reconfiguration of sensory-motor mapping. Based on this principle, we developed a biologically realistic model with multiple modules for task switching. We found that the model quantitatively accounts for complex task switching behavior: switch cost, congruency effect, and task-response interaction; as well as monkey's single-neuron activity associated with task switching. The model yields several testable predictions, in particular, that category-selective neurons play a key role in resolving sensory-motor conflict. This work represents a neural circuit model for task switching and sheds insights in the brain mechanism of a fundamental cognitive capability. PMID:24336717

Ardid, Salva; Wang, Xiao-Jing

2013-12-11

218

Do NIRS measures relate to subjective low back discomfort during sedentary tasks?  

Microsoft Academic Search

Sedentary tasks such as sitting or standing are often a required task components of industrial occupations. Due to automation, industrial job changes to more computer based tasks, and job ergonomic (re)design, the exposure to heavy lifting and awkward postures is being reduced and subsequently resulting in increased duration of work time spent in sedentary non-varying postures. Prolonged standing and seated

Jack P. Callaghan; Diane E. Gregory; Jennifer L. Durkin

2010-01-01

219

Object-based task-level control: A hierarchical control architecture for remote operation of space robots  

NASA Technical Reports Server (NTRS)

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.

Stevens, H. D.; Miles, E. S.; Rock, S. J.; Cannon, R. H.

1994-01-01

220

Task-Shifting in HIV Care: A Case Study of Nurse-Centered Community-Based Care in Rural Haiti  

PubMed Central

Introduction At least 36 countries are suffering from severe shortages of healthcare workers and this crisis of human resources in developing countries is a major obstacle to scale-up of HIV care. We performed a case study to evaluate a health service delivery model where a task-shifting approach to HIV care had been undertaken with tasks shifted from doctors to nurses and community health workers in rural Haiti. Methods Data were collected using mixed quantitative and qualitative methods at three clinics in rural Haiti. Distribution of tasks for HIV services delivery; types of tasks performed by different cadres of healthcare workers; HIV program outcomes; access to HIV care and acceptability of the model to staff were measured. Results A shift of tasks occurred from doctors to nurses and to community health workers compared to a traditional doctor-based model of care. Nurses performed most HIV-related tasks except initiation of TB therapy for smear-negative suspects with HIV. Community health workers were involved in over half of HIV-related tasks. HIV services were rapidly scaled-up in the areas served; loss to follow-up of patients living with HIV was less than 5% at 24 months and staff were satisfied with the model of care. Conclusion Task-shifting using a community-based, nurse-centered model of HIV care in rural Haiti is an effective model for scale-up of HIV services with good clinical and program outcomes. Community health workers can provide essential health services that are otherwise unavailable particularly in rural, poor areas. PMID:21573152

Ivers, Louise C.; Jerome, Jean-Gregory; Cullen, Kimberly A.; Lambert, Wesler; Celletti, Francesca; Samb, Badara

2011-01-01

221

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...

222

PHARMACOKINETICALLY BASED RISK ASSESSMENT OF WORKPLACE EXPOSURE OF BENZENE  

EPA Science Inventory

Cancer risk from exposure to benzene for a working lifetime was estimated from data obtained in studies with rodents. ancers of the Zymbal gland and the blood-forming system were selected as endpoints for the assessment because of their consistent occurrence. he combined metaboli...

223

Analogical-mapping-based comparison tasks as a scaffold for argumentation  

NASA Astrophysics Data System (ADS)

Given the centrality of the argumentation process to science and consequent importance to science education, inviting science students to engage in argumentation and scaffolding that argumentation in order that it lead to learning and not frustration is important. The present research invites small groups of science content learners (54 preservice elementary teachers at a large research university) to use analogical-mapping-based comparison tasks in service of argumentation to determine which of two possible analogues, in this case simple machines, is most closely related to a third. These activities and associated instruction scaffolded student small-groups' argumentation in four ways: (1) supporting new analogical correspondences on the heels of prior correspondences; (2) discerning definitions and descriptions for simple machine elements; (3) identifying and dealing with ambiguity in potential correspondences; and (4) making reflections on prior analogical correspondences in service of their final arguments. Analogical-mapping-based comparison activities scaffolded student small groups both in their argumentation and in content learning about simple machines. Implications, limitations, and directions for future related research are also discussed.

Emig, Brandon R.

224

MAX meets ADAM: a dosimetric comparison between a voxel-based and a mathematical model for external exposure to photons  

NASA Astrophysics Data System (ADS)

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.

Kramer, R.; Vieira, J. W.; Khoury, H. J.; Lima, F. de Andrade

2004-03-01

225

Biology Based Lung Cancer Model for Chronic Low Radon Exposures  

NASA Astrophysics Data System (ADS)

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.

Truţ?-Popa, Lucia-Adina; Hofmann, Werner; Fakir, Hatim; Cosma, Constantin

2008-08-01

226

Generating Politeness in Task Based Interaction: An Evaluation of the Effect of Linguistic Form and Culture  

E-print Network

and Culture Swati Gupta Department of Computer Science, University of Sheffield Regent Court, 211 Portobello), real estate sales (Cassell & Bickmore, 2003), and has also shown that the cross-cultural claims of B politeness strategies in task-oriented dialogues in a collaborative task domain of cooking, where #12;Figure

Romano, Daniela

227

The Impact of Planning Time on Children's Task-Based Interactions  

ERIC Educational Resources Information Center

Recently, tasks have been advocated for their role in promoting participation in L2 interaction and the provision and use of feedback by language learners (Bygate, M., Skehan, P., Swain, M. (Eds.), 2001. "Researching Pedagogical Tasks: Second Language Learning, Teaching and Testing." Pearson Education, Harlow). The relationship between various…

Philp, Jenefer; Oliver, Rhonda; Mackey, Alison

2006-01-01

228

Machine Learning Based Online Performance Prediction for Runtime Parallelization and Task Scheduling  

SciTech Connect

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.

Li, J; Ma, X; Singh, K; Schulz, M; de Supinski, B R; McKee, S A

2008-10-09

229

Rethinking Task-Based Language Learning: What We Can Learn from the Learners  

ERIC Educational Resources Information Center

To investigate the use, or otherwise, of conversational adjustments (CAs), in a normal instructional setting, the quality of speech generated during meaning negotiation, and learner perception of the task under study, a quantitative and a qualitative analysis was carried out of language produced in a dyadic set-up in a one-way information task, a…

Slimani-Rolls, Assia

2005-01-01

230

Lunar surface construction and assembly equipment study: Lunar Base Systems Study (LBSS) task 5.3  

NASA Technical Reports Server (NTRS)

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.

1988-01-01

231

Applying the task-technology fit model to WWW-based conceptualization and measurement  

Microsoft Academic Search

This research examines the application of the task-technology fit (TTF) model to World Wide Web (WWW) usage for electronic commerce (EC) purposes. Conducted from corporate buyers' perspective, this study assesses the extent to which Internet websites in general support the procurement process. The model suggests that a better fit between the tasks required during the procurement process and Internet Web

Younes Benslimane; Michel Plaisent; Prosper Bernard

2003-01-01

232

A task-based analysis of machinery entanglement injuries among Western Canadian farmers.  

PubMed

Machinery entanglements are a leading cause of hospitalized injury on Canadian farms. This study evaluates the role farm tasks play in the occurrence of machinery entanglement events. A retrospective case series of 41 entanglement injuries involving 35 farm-machinery types was assembled. Only a few limited tasks were implicated in the majority of entanglements. These tasks were as follows: (1) field adjustments of machinery; (2) product handling and conveyance; and (3) driveline attachments and servicing. Hazards inherent and common to these tasks affected the behavior of farmers, leading to entanglements. This study establishes a need to identify hazards and assess risks associated with different tasks involving the use of farm machinery under actual field situations. Systemic changes are required to improve existing machinery safety practices through engineering, work methods, and work practice modifications. In addition to design solutions, occupational health and safety strategies should consider activities associated with hazardous situations to inform the content of injury prevention efforts. PMID:21958400

Narasimhan, Gopinath; Crowe, Trever G; Peng, Yingwei; Hagel, Louise; Dosman, James; Pickett, William

2011-10-01

233

Sequential task predictability in task switching  

Microsoft Academic Search

Many studies of task switching have found that a prolonged preparation time reduces switch costs. An alternative manipulation\\u000a of task preparation is based on sequential task predictability, rather than preparation time. In Experiments 1 and 2 of the\\u000a present study, participants performed explicitly instructed task sequences (i.e., AABB) and were then transferred to a random\\u000a sequence. The observed benefit of

Iring Koch; Max Planck

2005-01-01

234

Community-based rehabilitation programme as a model for task-shifting.  

PubMed

This article explores some of the implications of a non-governmental organisation (NGO) initiated community-based rehabilitation (CBR) programme, for HIV-related task-shifting programmes which have been recommended by the World Health Organisation (WHO) as an important aspect of HIV prevention, treatment and care programmes. The CBR programme is run by multi-skilled community rehabilitation facilitators (CRFs) in a low income, rural context in KwaZulu-Natal, South Africa, and explicitly recognises the multiple facets of disability. As such, the programme focuses on both the physical and social aspects of living with disabilities. A qualitative approach was used to conduct this study, and semi-structured interviews were conducted with beneficiaries of the programme (n?=?35), home and community-based care givers (HCBCs) (n?=?13), and managers (n?=?2). A focus group discussion was conducted with CRFs (n?=?5). We found that the CBR programme successfully delivered rehabilitation services at a community level and that multi-skilled CRFs are an effective means of implementing CBR programmes in low-income rural areas. The developmental focus of the programme created a range of benefits for people with disabilities, including: physical rehabilitation, emotional support and counselling, access to grants, social inclusion and accessing assistive devices. Central to the programme's success was the maintenance of relationships and partnerships at different levels in the community, these included relationships between HCBCs and CRFs, between CRFs and therapists, and between the NGO and the various participants in the programme. However, the NGO struggled to maintain a partnership with the relevant government departments and this had important implications for the programmes sustainability. In conclusion, we argue that this programme's use of multi-skilled mid-level workers who have undergone effective training programmes in CBR demonstrates that a wide range of rehabilitation activities can be effectively undertaken at a community level, and that this programme provides an important example of how the WHO's task-shifting guidelines for HIV treatment, care and prevention can be implemented. PMID:21291340

Dawad, Suraya; Jobson, Geoff

2011-01-01

235

Task Performance in Astronomical Adaptive Optics  

PubMed Central

In objective or task-based assessment of image quality, figures of merit are defined by the performance of some specific observer on some task of scientific interest. This methodology is well established in medical imaging but is just beginning to be applied in astronomy. In this paper we survey the theory needed to understand the performance of ideal or ideal-linear (Hotelling) observers on detection tasks with adaptive-optical data. The theory is illustrated by discussing its application to detection of exoplanets from a sequence of short-exposure images. PMID:20890393

Barrett, Harrison H.; Myers, Kyle J.; Devaney, Nicholas; Dainty, J. C.; Caucci, Luca

2010-01-01

236

VCSEL array-based light exposure system for laser printing  

Microsoft Academic Search

Improving the image quality and speed is an endless demand for printer applications. To meet the market requirements, we have launched the world first laser printer (DocuColor 1256 GA) introducing 780-nm single-mode 8×4 VCSEL arrays in the light exposure system in 2003. The DocuColor 1256 GA features 2400 dots per inch (dpi) resolution which is the highest in the industry

Naotaka Mukoyama; Hiromi Otoma; Jun Sakurai; Nobuaki Ueki; Hideo Nakayama

2008-01-01

237

Paleoglaciation of the Tibetan Plateau based on exposure ages and ELA depression estimates  

NASA Astrophysics Data System (ADS)

The Tibetan Plateau holds a major part of all glaciers outside the polar regions and an ample record of past glaciations. The glacial history of the Tibetan Plateau has attracted significant interest, with a large body of research investigating the extent, timing, and climatic implications of past glaciations. Here I present an extensive compilation of exposure ages and equilibrium line altitude (ELA) depression estimates from glacial deposits across the Tibetan Plateau to address the timing and degree of past glaciations. I compiled Be-10 exposure age data for a total of 1877 samples and recalculated exposure ages using an updated (lower) global Be-10 production rate. All samples were organized in groups of individual glacial deposits where each deposit represents one glacial event enabling evaluation of the exposure age clustering. For each glacial deposit I estimated the ELA depression based on a simple toe to headwall ratio approach using Google Earth. To discriminate good (well-clustered) from poor (scattered) exposure age groups the glacial deposits were divided into three groups based on exposure age clustering. A major part of the glacial deposits have scattered exposure ages affected by prior or incomplete exposure, complicating exposure age interpretations. The well-clustered exposure age groups are primarily from mountain ranges along the margins of the Tibetan Plateau with a main peak in age between 10 and 30 ka, indicating glacial advances during the global last glacial maximum (LGM). A large number of exposure ages older than 30 ka indicates maximum glaciation predating the LGM, but the exposure age scatter generally prohibits accurate definition of the glacial chronology. The ELA depression estimates scatter significantly, but a major part is remarkably low. Average ELA depressions of 333 ± 191 m for the LGM and 494 ± 280 m for the pre-LGM exposure indicate restricted glacier expansion and limited glacial cooling.

Heyman, Jakob

2014-05-01

238

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

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)

Nunan, David; And Others

1994-01-01

239

Inferring multi-target QSAR models with taxonomy-based multi-task learning  

PubMed Central

Background A plethora of studies indicate that the development of multi-target drugs is beneficial for complex diseases like cancer. Accurate QSAR models for each of the desired targets assist the optimization of a lead candidate by the prediction of affinity profiles. Often, the targets of a multi-target drug are sufficiently similar such that, in principle, knowledge can be transferred between the QSAR models to improve the model accuracy. In this study, we present two different multi-task algorithms from the field of transfer learning that can exploit the similarity between several targets to transfer knowledge between the target specific QSAR models. Results We evaluated the two methods on simulated data and a data set of 112 human kinases assembled from the public database ChEMBL. The relatedness between the kinase targets was derived from the taxonomy of the humane kinome. The experiments show that multi-task learning increases the performance compared to training separate models on both types of data given a sufficient similarity between the tasks. On the kinase data, the best multi-task approach improved the mean squared error of the QSAR models of 58 kinase targets. Conclusions Multi-task learning is a valuable approach for inferring multi-target QSAR models for lead optimization. The application of multi-task learning is most beneficial if knowledge can be transferred from a similar task with a lot of in-domain knowledge to a task with little in-domain knowledge. Furthermore, the benefit increases with a decreasing overlap between the chemical space spanned by the tasks. PMID:23842210

2013-01-01

240

The Relationship between Event-Based Prospective Memory and Ongoing Task Performance in Chimpanzees (Pan troglodytes)  

PubMed Central

Prospective memory is remembering to do something at a future time. A growing body of research supports that prospective memory may exist in nonhuman animals, but the methods used to test nonhuman prospective memory differ from those used with humans. The current work tests prospective memory in chimpanzees using a method that closely approximates a typical human paradigm. In these experiments, the prospective memory cue was embedded within an ongoing task. Tokens representing food items could be used in one of two ways: in a matching task with pictures of items (the ongoing task) or to request a food item hidden in a different location at the beginning of the trial. Chimpanzees had to disengage from the ongoing task in order to use the appropriate token to obtain a higher preference food item. In Experiment 1, chimpanzees effectively matched tokens to pictures, when appropriate, and disengaged from the ongoing task when the token matched the hidden item. In Experiment 2, performance did not differ when the target item was either hidden or visible. This suggested no effect of cognitive load on either the prospective memory task or the ongoing task, but performance was near ceiling, which may have contributed to this outcome. In Experiment 3, we created a more challenging version of the task. More errors on the matching task occurred before the prospective memory had been carried out, and this difference seemed to be limited to the hidden condition. This finding parallels results from human studies and suggests that working memory load and prospective memory may have a similar relationship in nonhuman primates. PMID:25372809

Evans, Theodore A.; Perdue, Bonnie; Beran, Michael J.

2014-01-01

241

Aging and performance on an everyday-based visual search task.  

PubMed

Research on aging and visual search often requires older people to search computer screens for target letters or numbers. The aim of this experiment was to investigate age-related differences using an everyday-based visual search task in a large participant sample (n=261) aged 20-88 years. Our results show that: (1) old-old adults have more difficulty with triple conjunction searches with one highly distinctive feature compared to young-old and younger adults; (2) age-related declines in conjunction searches emerge in middle age then progress throughout older age; (3) age-related declines are evident in feature searches on target absent trials, as older people seem to exhaustively and serially search the whole display to determine a target's absence. Together, these findings suggest that declines emerge in middle age then progress throughout older age in feature integration, guided search, perceptual grouping and/or spreading suppression processes. Discussed are implications for enhancing everyday functioning throughout adulthood. PMID:22664318

Potter, Lauren M; Grealy, Madeleine A; Elliott, Mark A; Andrés, Pilar

2012-07-01

242

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...

243

Multiple templates auto exposure control based on luminance histogram for onboard camera  

Microsoft Academic Search

In order to adjust the exposure of high resolution and frequency images from an on-board camera in real time, a simple exposure control approach based on luminance histogram analysis is presented to realize light control precisely and rapidly. The algorithm divides the initial image into nine blocks and calculates the mean brightness of every part. It uses the luminance histogram

Tao Jiang; K.-D. Kuhnert; Duong Nguyen; Lars Kuhnert

2011-01-01

244

A comparison of exposure methods for SPME-based bioavailability estimates  

Microsoft Academic Search

The ability of polydimethlysiloxane coated solid phase microextraction (SPME) fibers to predict bioavailability has been documented for a number of species and compounds. There are also a variety of established methods for establishing SPME-based bioavailability estimates; however, factors such as time until equilibrium and exposure regimen could affect fiber concentrations and have not yet been thoroughly tested. Exposure time may

Amanda D. Harwood; Peter F. Landrum; Michael J. Lydy

245

An Online Trajectory Generator-Based Impedance Control For Co-manipulation Tasks  

E-print Network

and accuracy, since they can alert the user for changes in the state of the environment and support hand-eye coordination for object manipulation tasks. During PHRI, the skills of HO and industrial robot should

246

Knowledge-Based Schematics Drafting: Aesthetic Configuration as a Design Task  

E-print Network

Depicting an electrical circuit by a schematic is a tedious task that is a good candidate for automation. Programs that draft schematics with the usual algorithmic approach do not fully exploit knowledge of circuit function, ...

Valdes-Perez, Raul E.

247

Paleoglaciation of the Tibetan Plateau and surrounding mountains based on exposure ages and ELA depression estimates  

NASA Astrophysics Data System (ADS)

The Tibetan Plateau holds an ample record of past glaciations, and there is an extensive set of glacial deposits dated by exposure dating. Here a compilation is presented of 10Be exposure ages from 485 glacial deposits with 1855 individual samples on the Tibetan Plateau, and ELA depression estimates for the glacial deposits based on a simple toe to headwall ratio approach. To recalculate the Tibetan Plateau exposure ages, 10Be production rates from 24 calibration sites across the world are compiled and recalibrated yielding an updated global reference 10Be production rate. The recalculated exposure ages from the Tibetan Plateau glacial deposits are then divided into three groups based on exposure age clustering, to discriminate good (well-clustered) from poor (scattered) deglaciation ages. A major part of the glacial deposits have exposure ages affected by prior or incomplete exposure, complicating exposure age interpretations. The well-clustered deglaciation ages are primarily from mountain ranges along the margins of the Tibetan Plateau with a main peak between 10 and 30 ka, indicating glacial advances during the global LGM. A large number of deglaciation ages older than 30 ka indicates maximum glaciation predating the LGM, but the exposure age scatter generally prohibits accurate definition of the glacial chronology. The ELA depression estimates scatter significantly, but the main part is remarkably low. Average ELA depressions of 337 ± 197 m for the LGM and 494 ± 280 m for the pre-LGM indicate restricted glacier expansion.

Heyman, Jakob

2014-05-01

248

Task Analysis Based Methodology for the Design of Face to Face Computer Supported Collaborative Learning Activities  

Microsoft Academic Search

\\u000a This paper shows how Task Analysis can be a powerful tool for the design of collaborative applications supported by wirelessly\\u000a interconnected handhelds. We define a methodology for the design of such activities. It basically consists in performing a\\u000a Task Analysis on an Interaction Model to obtain the set of all possible interactions between actors. Then a class of activities\\u000a is

Maria Francisca Capponi; Miguel Nussbaum; María Ester Lagos

2006-01-01

249

Can time-based decay explain temporal distinctiveness effects in task switching?  

PubMed

In task switching, extending the response-cue interval (RCI) reduces the switch cost-the detriment to performance when switching compared to repeating tasks. This reduction has been used as evidence for the existence of task-set decay processes. Recently, this has been challenged by the observation of sequential dependencies on the RCI effect: switch cost is only reduced at longer RCIs when the previous trial had a short RCI. This trial-wise variation of RCI is thought to affect the temporal distinctiveness (TD) of a previous task's episodic trace, affecting the probability of its automatic retrieval on the current trial; importantly, TD is thought to be independent of the current trial's RCI. The present study highlights a dependency between the current RCI and TD, and demonstrates that a decay model can reproduce some patterns of data attributed to TD. Further, the decay account makes a strong prediction when TD is held constant: repetition response times should slow as the RCI increases, and switch response times should be facilitated. This prediction was tested via re-analysis of extant data and three experiments. The re-analysis provided some evidence for the decay account, but Experiments 1 and 2 report slowing for task repetition and switch trials, which cannot be explained by a task-set decay process. Experiment 3, which utilized tasks requiring perceptual judgements, showed small evidence for decay. We conclude that the data are largely consistent with the TD account and that the evidence for decay of higher-level task-sets is not convincing. PMID:25028178

Grange, James A; Cross, Ellen

2015-01-01

250

Reading Guided by Automated Graphical Representations: How Model-Based Text Visualizations Facilitate Learning in Reading Comprehension Tasks  

ERIC Educational Resources Information Center

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…

Pirnay-Dummer, Pablo; Ifenthaler, Dirk

2011-01-01

251

"Lo Cotidiano": The Effectiveness of Critical Task-Based Instruction in Teaching the Culture of Everyday Life  

ERIC Educational Resources Information Center

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…

García-Villada, Eduardo

2014-01-01

252

A learning scheme for reach to grasp movements: on EMG-based interfaces using task specific motion decoding models.  

PubMed

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. PMID:25055370

Liarokapis, Minas V; Artemiadis, Panagiotis K; Kyriakopoulos, Kostas J; Manolakos, Elias S

2013-09-01

253

A Theory of the Task-based Information Retrieval Process: A Summary and Generalisation of a Longitudinal Study.  

ERIC Educational Resources Information Center

Summarizes empirical results reported earlier on relations between students' problem stages (mental model) in writing research proposals for a masters' thesis and the information sought, choice of search terms, and relevance assessments; refines Kuhlthau's model of the information search process; and proposes a theory of a task-based information…

Vakkari, Pertti

2001-01-01

254

Comparing the Outcomes of Online Listening versus Online Text-Based Tasks in University Level Italian L2 Study  

ERIC Educational Resources Information Center

In this paper, we describe an initial exploratory study designed to compare the outcomes of online listening and online text-based tasks in the context of the study of Italian at The University of Melbourne. Our findings allow us to characterise online listening and online reading as a qualitative difference between deep and surface approaches to…

Absalom, Matthew; Rizzi, Andrea

2008-01-01

255

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

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.…

Vandana, V. P.

2007-01-01

256

Toward a Domain-Independent Framework to Automate Scaffolding of Task-Based Learning in Digital Games  

E-print Network

Games James M. Thomas Digital Games Research Center Liquid Narrative Research Group North Carolina State University jmthoma5@ncsu.edu R. Michael Young Digital Games Research Center Liquid Narrative Research Group of intelligent tutoring systems. Keywords Task-Based Learning, Interactive Narrative, Digital Games, Scaffolding

Young, R. Michael

257

Teacher- and Learner-Led Discourse in Task-Based Grammar Instruction: Providing Procedural Assistance for L2 Morphosyntactic Development  

ERIC Educational Resources Information Center

This study compares quantitative and qualitative results for task-based second language (L2) grammar instruction conducted as whole-class, teacher-led discourse (TLD) versus small-group, learner-led discourse (LLD). Participants included 78 English-speaking adults from six university classes of beginning L2 Spanish, with two assigned to each…

Toth, Paul D.

2008-01-01

258

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

ERIC Educational Resources Information Center

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…

Lin, Tzu-Bin; Wu, Chiao-Wen

2012-01-01

259

Analysis of radiation exposure for Task Force Big Bang, Shot Galileo. Exercise Desert Rock VII-VIII Operation Plumbbob. Final report, 27 February 1978-19 July 1979  

SciTech Connect

The radiation doses to Task Force BIG BANG troops who participated in Shot GALILEO are determined and compared with film badge data gathered during Exercise Desert Rock VII-VIII. Fallout contours and decay rates, are established and used to calculate total external beta and gamma doses, based on estimated stay time for various troop activities. Uncertainties are calculated for each parameter. Radiation dose from internal emitters, due to inhalation of resuspended contaminated particles, is calculated. Total external gamma dose is estimated to be 1070-1780 mrem as compared with a mean film badge reading of 1900 mrem. 50-year bone dose, due to internal emitters, is estimated to be 10-25 mrem.

Goetz, J.L.; Kaul, D.; Klemm, J.; McGahan, J.T.; McRaney, W.K.

1980-04-09

260

Comparative evaluation of twenty pilot workload assessment measure using a psychomotor task in a moving base aircraft simulator  

NASA Technical Reports Server (NTRS)

A comparison of the sensitivity and intrusion of twenty pilot workload assessment techniques was conducted using a psychomotor loading task in a three degree of freedom moving base aircraft simulator. The twenty techniques included opinion measures, spare mental capacity measures, physiological measures, eye behavior measures, and primary task performance measures. The primary task was an instrument landing system (ILS) approach and landing. All measures were recorded between the outer marker and the middle marker on the approach. Three levels (low, medium, and high) of psychomotor load were obtained by the combined manipulation of windgust disturbance level and simulated aircraft pitch stability. Six instrument rated pilots participated in four seasons lasting approximately three hours each.

Connor, S. A.; Wierwille, W. W.

1983-01-01

261

Evaluating exposure to radio-frequency emissions from base station antennas  

Microsoft Academic Search

The availability of efficient, reliable and reasonably simple procedures providing assistance in evaluating human exposure to radiofrequency fields from base station antennas is essential for mobile communications. In this paper, sample results of \\

Andrzej Karwowski

2002-01-01

262

Cooperative scheduling of imaging observation tasks for high-altitude airships based on propagation algorithm.  

PubMed

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

Chuan, He; Dishan, Qiu; Jin, Liu

2012-01-01

263

Cooperative Scheduling of Imaging Observation Tasks for High-Altitude Airships Based on Propagation Algorithm  

PubMed Central

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

Chuan, He; Dishan, Qiu; Jin, Liu

2012-01-01

264

New exposure-based metric approach for evaluating O 3 risk to North American aspen forests  

Microsoft Academic Search

The United States and Canada currently use exposure-based metrics to protect vegetation from O3. Using 5years (1999–2003) of co-measured O3, meteorology and growth response, we have developed exposure-based regression models that predict Populus tremuloides growth change within the North American ambient air quality context. The models comprised growing season fourth-highest daily maximum 8-h average O3 concentration, growing degree days, and

K. E. Percy; M. Nosal; W. Heilman; T. Dann; J. Sober; A. H. Legge; D. F. Karnosky

2007-01-01

265

THE WORKPLACE EXPOSURE ASSESSMENT EXPERT SYSTEM (WORKSPERT)  

Microsoft Academic Search

The fundamental principles of industrial hygiene are based upon the recognition, evaluation, and control of workplace hazards. Occupational safety and health professionals (e.g., industrial hygienists) perform this task by assessing numerous complex factors. In many situations industrial hygienists are not available; therefore, an expert system has been developed to assist the performance of workplace exposure assessments (WEAs). The Workplace Exposure

Keith Tait

1992-01-01

266

Text, Graphics, and Multimedia Materials Employed in Learning a Computer-Based Procedural Task  

ERIC Educational Resources Information Center

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…

Coffindaffer, Kari Christine Carlson

2010-01-01

267

The association between health anxiety and disgust reactions in a contamination-based behavioral approach task  

Microsoft Academic Search

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,

Amy R. Goetz; Han-Joo Lee; Jesse R. Cougle

2012-01-01

268

Learning Effects in the Block Design Task: A Stimulus Parameter-Based Approach  

ERIC Educational Resources Information Center

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,…

Miller, Joseph C.; Ruthig, Joelle C.; Bradley, April R.; Wise, Richard A.; Pedersen, Heather A.; Ellison, Jo M.

2009-01-01

269

Task analyzed masturbation instruction for a profoundly mentally retarded adult male: A data based case study  

Microsoft Academic Search

This report presents task analyzed masturbation instruction for a 29 year old profoundly mentally retarded male. This individual's sole method of masturbation was to rub his penis against the floor or bed mattress which resulted in very infrequent ejaculations and was potentially dangerous to his genitalia. It was decided to teach this individual a more safe and effective method of

Frederick Kaeser; John O'Neill

1987-01-01

270

Artificial Neural Network-based Hybrid Force\\/Position Control of an Assembly Task  

Microsoft Academic Search

In the case of complex robotics tasks, pure position control is ineffective since forces appearing during the contacts must also be controlled. However, simultaneous position and force control called hybrid control is then required. Moreover, the non-linear plant dynamics, the complexity of the dynamic parameters determination and computation constraints makes more difficult the synthesis of control laws. In order to

Y. Touati; Y. Amirat; N. Saadia

2006-01-01

271

Classroom-Based Functional Analysis and Intervention for Disruptive and Off-Task Behaviors  

ERIC Educational Resources Information Center

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…

Shumate, Emily D.; Wills, Howard P.

2010-01-01

272

Interactional Feedback in Learner-Learner Interactions in a Task-Based EFL Classroom  

ERIC Educational Resources Information Center

This research explores learner-learner interactions (n = 18) in an authentic EFL classroom. First, we examined the nature of interactional feedback provided during two decision-making tasks. We then investigated whether the learners had made use of the feedback by looking at whether (and if so, how) they had modified their output immediately after…

Fujii, Akiko; Mackey, Alison

2009-01-01

273

Attentional and intentional cueing in a Simon task: An EEG-based approach  

Microsoft Academic Search

Advance information about the location of a stimulus (attentional cueing) does not affect the Simon effect (a shortening of manual response times whenever the position of a stimulus that is irrelevant for the task corresponds to the side of the response). However, advance information about the side of a response (intentional cueing) enhances the Simon effect. At first sight, these

Edmund Wascher; M. Wolber

2004-01-01

274

Conflict tasks and the diffusion framework: Insight in model constraints based on psychological laws.  

PubMed

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. PMID:24762975

Servant, Mathieu; Montagnini, Anna; Burle, Borís

2014-07-01

275

OccIDEAS: Retrospective Occupational Exposure Assessment in Community-Based Studies Made Easier  

PubMed Central

Assessing occupational exposure in retrospective community-based case-control studies is difficult as measured exposure data are very seldom available. The expert assessment method is considered the most accurate way to attribute exposure but it is a time consuming and expensive process and may be seen as subjective, nonreproducible, and nontransparent. In this paper, we describe these problems and outline our solutions as operationalized in a web-based software application (OccIDEAS). The novel aspects of OccIDEAS are combining all steps in the assessment into one software package; enmeshing the process of assessment into the development of questionnaires; selecting the exposure(s) of interest; specifying rules for exposure assignment; allowing manual or automatic assessments; ensuring that circumstances in which exposure is possible for an individual are highlighted for review; providing reports to ensure consistency of assessment. Development of this application has the potential to make high-quality occupational assessment more efficient and accessible for epidemiological studies. PMID:20041014

Fritschi, Lin; Friesen, Melissa C.; Glass, Deborah; Benke, Geza; Girschik, Jennifer; Sadkowsky, Troy

2009-01-01

276

International data base of exposure measurements in the pulp, paper and paper product industries  

Microsoft Academic Search

An international data base of exposure measurements in the pulp, paper and paper product industries was constructed to be\\u000a used in exposure assessment for epidemiology studies and hazard control. Industrial hygiene and biological monitoring data\\u000a were collected from countries participating in the multicentric study of the International Agency for Research on Cancer.\\u000a Each measurement was characterized by country, mill type

Timo Kauppinen; Kay Teschke; Anja Savela; Manolis Kogevinas; Paolo Boffetta

1997-01-01

277

Probabilistic modeling of percutaneous absorption for risk-based exposure assessments and transdermal drug delivery  

Microsoft Academic Search

Chemical transport through human skin can play a significant role in human exposure to toxic chemicals in the workplace, as well as to chemical\\/biological warfare agents in the battlefield. The viability of transdermal drug delivery also relies on chemical transport processes through the skin. Models of percutaneous absorption are needed for risk-based exposure assessments and drug-delivery analyses, but previous mechanistic

Clifford K. Ho

2004-01-01

278

Biologically based modeling of multimedia, multipathway, multiroute population exposures to arsenic  

Microsoft Academic Search

This article presents an integrated, biologically based, source-to-dose assessment framework for modeling multimedia\\/multipathway\\/multiroute exposures to arsenic. Case studies demonstrating this framework are presented for three US counties (Hunderton County, NJ; Pima County, AZ; and Franklin County, OH), representing substantially different conditions of exposure. The approach taken utilizes the Modeling ENvironment for TOtal Risk studies (MENTOR) in an implementation that incorporates

Panos G Georgopoulos; Sheng-Wei Wang; Yu-Ching Yang; Jianping Xue; Valerie G Zartarian; Thomas Mccurdy; Halûk Özkaynak

2008-01-01

279

The effect of pre-exposure and recovery type on activity-based anorexia in rats  

Microsoft Academic Search

Activity-based anorexia (ABA) occurs when there is limited access to food and an opportunity to engage in high levels of physical activity. While the ABA effect is well established, the distinct functions of exercise and food restriction in maintaining ABA have not been determined. The current study examined the effect of pre-exposure to a restricted feeding schedule and pre-exposure to

Yevgeniya Ratnovsky; Paul Neuman

2011-01-01

280

1H NMR-based metabonomic investigation of tributyl phosphate exposure in rats  

Microsoft Academic Search

Tributyl phosphate (TBP) is a toxic organophosphorous compound widely used in many industrial applications, including significant usage in nuclear processing. The industrial application of this chemical is responsible for occupational exposure and environmental pollution. In this study, 1H NMR-based metabonomics has been applied to investigate the metabolic response to TBP exposure. Male Sprague-Dawley rats were given a TBP-dose of 15mg\\/kg

Muniasamy Neerathilingam; David E. Volk; Swapna Sarkar; Todd M. Alam; M. Kathleen Alam; G. A. Shakeel Ansari; Bruce A. Luxon

2010-01-01

281

Task switching  

Microsoft Academic Search

Everyday life requires frequent shifts between cognitive tasks. Research reviewed in this article probes the control processes that reconfigure mental resources for a change of task by requiring subjects to switch frequently among a small set of simple tasks. Subjects' responses are substantially slower and, usually, more error-prone immediately after a task switch. This ‘switch cost’ is reduced, but not

Stephen Monsell

2003-01-01

282

Task-independent robotic uncalibrated hand-eye coordination based on the extended state observer  

Microsoft Academic Search

This paper proposes a standard method to approach the uncalibrated robotic hand-eye coordination problem that is system configuration- and task-independent. The unknown hand-eye relationship is first modeled as the modeling errors of a dynamic system. An extended state observer is then implemented to estimate summation of the system's modeling error and the system's external disturbances. With the estimation results as

Jianbo Su; Hongyu Ma; Wenbin Qiu; Yugeng Xi

2004-01-01

283

Computer vision based wheel sinkage detection for robotic lunar exploration tasks  

Microsoft Academic Search

This paper presents a wheel sinkage detection method that may be used in robotic lunar exploration tasks. The method extracts the boundary line between a robot wheel and lunar soil by segmenting the wheel-soil images captured from a video camera that monitors wheel-soil interaction. The detected boundary is projected onto the soil-free image of the robot wheel to determine the

GuruPrasad Hegde; C. J. Robinson; Cang Ye; A. Stroupe; E. Tunstel

2010-01-01

284

Development of a software based automatic exposure control system for use in image guided radiation therapy  

NASA Astrophysics Data System (ADS)

Modern image guided radiation therapy involves the use of an isocentrically mounted imaging system to take radiographs of a patient's position before the start of each treatment. Image guidance helps to minimize errors associated with a patients setup, but the radiation dose received by patients from imaging must be managed to ensure no additional risks. The Varian On-Board Imager (OBI) (Varian Medical Systems, Inc., Palo Alto, CA) does not have an automatic exposure control system and therefore requires exposure factors to be manually selected. Without patient specific exposure factors, images may become saturated and require multiple unnecessary exposures. A software based automatic exposure control system has been developed to predict optimal, patient specific exposure factors. The OBI system was modelled in terms of the x-ray tube output and detector response in order to calculate the level of detector saturation for any exposure situation. Digitally reconstructed radiographs are produced via ray-tracing through the patients' volumetric datasets that are acquired for treatment planning. The ray-trace determines the attenuation of the patient and subsequent x-ray spectra incident on the imaging detector. The resulting spectra are used in the detector response model to determine the exposure levels required to minimize detector saturation. Images calculated for various phantoms showed good agreement with the images that were acquired on the OBI. Overall, regions of detector saturation were accurately predicted and the detector response for non-saturated regions in images of an anthropomorphic phantom were calculated to generally be within 5 to 10 % of the measured values. Calculations were performed on patient data and found similar results as the phantom images, with the calculated images being able to determine detector saturation with close agreement to images that were acquired during treatment. Overall, it was shown that the system model and calculation method could potentially be used to predict patients' exposure factors before their treatment begins, thus preventing the need for multiple exposures.

Morton, Daniel R.

285

A discussion of potential exposure metrics for use in epidemiological studies on human exposure to radiowaves from mobile phone base stations1  

Microsoft Academic Search

There is currently a high level of concern in many countries that exposure to radiowaves from mobile phone base stations may be hazardous to health. When investigating such suggested risks, epidemiologists need to define an exposure metric that can reliably discriminate between exposed and unexposed groups of people. We conducted a feasibility study to investigate if either short-term measurements of

JOACHIM SCHÜZ; SIMON MANN

2000-01-01

286

Age-related impairment in an event-based prospective-memory task.  

PubMed

Slides of famous people were presented to participants with the instructions to name each face and circle the trial number if the person was wearing glasses (prospective-memory target event). Participants in their 50s and 60s (n = 56) were more successful than participants in their 70s and 80s (n = 59) at both the naming an prospective-memory tasks. An age-related increase in the probability of forgetting replicated an earlier prospective-memory study (E. A. Maylor, 1993); in the present case, there was also an age-related decrease in the probability of recovery. These effects of age remained significant after other measures of current ability were taken into account, including intelligence, speed, and naming performance. For participants who were in both the earlier study (E. A. Maylor, 1993) and this study (n = 65), the correlation between prospective-memory performance on the 2 occasions was significant but only for younger participants. Performance in the prospective-memory task was entirely unrelated to performance in the naming task. PMID:8726372

Maylor, E A

1996-03-01

287

A Community-Based Initiative to Reduce Children's Exposure to Toxics in Household Products  

ERIC Educational Resources Information Center

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…

Blackman, Anne Berlin; Luskin, Jack

2006-01-01

288

"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...

289

Numerical modelling calculations for evaluating exposure to radio-frequency emissions from base station antennas  

Microsoft Academic Search

The availability of reliable, simple procedures providing assistance in evaluating human exposure to radiofrequency fields from base station antennas is essential for mobile communications. In the paper, sample results of 'rigorous' full-wave numerical analysis of the electromagnetic field morphology in vicinity of a representative base station (BS) panel antenna are presented. Having recognized the field morphology, two simple approximate calculational

Andnej Karwowski

2002-01-01

290

Studying permethrin exposure in flight attendants using a physiologically based pharmacokinetic model  

PubMed Central

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. PMID:23462847

Wei, Binnian; Isukapalli, Sastry S.; Weisel, Clifford P.

2014-01-01

291

High-throughput models for exposure-based chemical prioritization in the ExpoCast project.  

PubMed

The United States Environmental Protection Agency (U.S. EPA) must characterize potential risks to human health and the environment associated with manufacture and use of thousands of chemicals. High-throughput screening (HTS) for biological activity allows the ToxCast research program to prioritize chemical inventories for potential hazard. Similar capabilities for estimating exposure potential would support rapid risk-based prioritization for chemicals with limited information; here, we propose a framework for high-throughput exposure assessment. To demonstrate application, an analysis was conducted that predicts human exposure potential for chemicals and estimates uncertainty in these predictions by comparison to biomonitoring data. We evaluated 1936 chemicals using far-field mass balance human exposure models (USEtox and RAIDAR) and an indicator for indoor and/or consumer use. These predictions were compared to exposures inferred by Bayesian analysis from urine concentrations for 82 chemicals reported in the National Health and Nutrition Examination Survey (NHANES). Joint regression on all factors provided a calibrated consensus prediction, the variance of which serves as an empirical determination of uncertainty for prioritization on absolute exposure potential. Information on use was found to be most predictive; generally, chemicals above the limit of detection in NHANES had consumer/indoor use. Coupled with hazard HTS, exposure HTS can place risk earlier in decision processes. High-priority chemicals become targets for further data collection. PMID:23758710

Wambaugh, John F; Setzer, R Woodrow; Reif, David M; Gangwal, Sumit; Mitchell-Blackwood, Jade; Arnot, Jon A; Joliet, Olivier; Frame, Alicia; Rabinowitz, James; Knudsen, Thomas B; Judson, Richard S; Egeghy, Peter; Vallero, Daniel; Cohen Hubal, Elaine A

2013-08-01

292

Comparative international analysis of radiofrequency exposure surveys of mobile communication radio base stations  

PubMed Central

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

Rowley, Jack T; Joyner, Ken H

2012-01-01

293

Sensitivity Analyses of Exposure Estimates from a Quantitative Job-exposure Matrix (SYN-JEM) for Use in Community-based Studies  

PubMed Central

Objectives: We describe the elaboration and sensitivity analyses of a quantitative job-exposure matrix (SYN-JEM) for respirable crystalline silica (RCS). The aim was to gain insight into the robustness of the SYN-JEM RCS estimates based on critical decisions taken in the elaboration process. Methods: SYN-JEM for RCS exposure consists of three axes (job, region, and year) based on estimates derived from a previously developed statistical model. To elaborate SYN-JEM, several decisions were taken: i.e. the application of (i) a single time trend; (ii) region-specific adjustments in RCS exposure; and (iii) a prior job-specific exposure level (by the semi-quantitative DOM-JEM), with an override of 0 mg/m3 for jobs a priori defined as non-exposed. Furthermore, we assumed that exposure levels reached a ceiling in 1960 and remained constant prior to this date. We applied SYN-JEM to the occupational histories of subjects from a large international pooled community-based case–control study. Cumulative exposure levels derived with SYN-JEM were compared with those from alternative models, described by Pearson correlation (Rp) and differences in unit of exposure (mg/m3-year). Alternative models concerned changes in application of job- and region-specific estimates and exposure ceiling, and omitting the a priori exposure ranking. Results: Cumulative exposure levels for the study subjects ranged from 0.01 to 60 mg/m3-years, with a median of 1.76 mg/m3-years. Exposure levels derived from SYN-JEM and alternative models were overall highly correlated (Rp > 0.90), although somewhat lower when omitting the region estimate (Rp = 0.80) or not taking into account the assigned semi-quantitative exposure level (Rp = 0.65). Modification of the time trend (i.e. exposure ceiling at 1950 or 1970, or assuming a decline before 1960) caused the largest changes in absolute exposure levels (26–33% difference), but without changing the relative ranking (Rp = 0.99). Conclusions: Exposure estimates derived from SYN-JEM appeared to be plausible compared with (historical) levels described in the literature. Decisions taken in the development of SYN-JEM did not critically change the cumulative exposure levels. The influence of region-specific estimates needs to be explored in future risk analyses. PMID:22805750

Peters, Susan

2013-01-01

294

Chemical Exposure Assessment Program at Los Alamos National Laboratory: A risk based approach  

SciTech Connect

The University of California Contract And DOE Order 5480.10 require that Los Alamos National Laboratory (LANL) perform health hazard assessments/inventories of all employee workplaces. In response to this LANL has developed the Chemical Exposure Assessment Program. This program provides a systematic risk-based approach to anticipation, recognition, evaluation and control of chemical workplace exposures. Program implementation focuses resources on exposures with the highest risks for causing adverse health effects. Implementation guidance includes procedures for basic characterization, qualitative risk assessment, quantitative validation, and recommendations and reevaluation. Each component of the program is described. It is shown how a systematic method of assessment improves documentation, retrieval, and use of generated exposure information.

Stephenson, D.J.

1996-04-01

295

Response of Inconel 617 superalloy to combined ground-based and STS reentry exposure  

NASA Technical Reports Server (NTRS)

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.

Clark, R. K.; Unnam, J.

1984-01-01

296

A Multilevel Modeling Approach to Examining Individual Differences in Skill Acquisition for a Computer-Based Task  

PubMed Central

This article explores the role of age, cognitive abilities, prior experience, and knowledge in skill acquisition for a computer-based simulated customer service task. Fifty-two participants aged 50–80 performed the task over 4 consecutive days following training. They also completed a battery that assessed prior computer experience and cognitive abilities. The data indicated that overall quality and efficiency of performance improved with practice. The predictors of initial level of performance and rate of change in performance varied according to the performance parameter assessed. Age and fluid intelligence predicted initial level and rate of improvement in overall quality, whereas crystallized intelligence and age predicted initial e-mail processing time, and crystallized intelligence predicted rate of change in e-mail processing time over days. We discuss the implications of these findings for the design of intervention strategies. PMID:17565169

Nair, Sankaran N.; Czaja, Sara J.; Sharit, Joseph

2008-01-01

297

AutomaDeD: Automata-Based Debugging for Dissimilar Parallel Tasks  

SciTech Connect

Today's largest systems have over 100,000 cores, with million-core systems expected over the next few years. This growing scale makes debugging the applications that run on them a daunting challenge. Few debugging tools perform well at this scale and most provide an overload of information about the entire job. Developers need tools that quickly direct them to the root cause of the problem. This paper presents AutomaDeD, a tool that identifies which tasks of a large-scale application first manifest a bug at a specific code region at a specific point during program execution. AutomaDeD creates a statistical model of the application's control-flow and timing behavior that organizes tasks into groups and identifies deviations from normal execution, thus significantly reducing debugging effort. In addition to a case study in which AutomaDeD locates a bug that occurred during development of MVAPICH, we evaluate AutomaDeD on a range of bugs injected into the NAS parallel benchmarks. Our results demonstrate that detects the time period when a bug first manifested itself with 90% accuracy for stalls and hangs and 70% accuracy for interference faults. It identifies the subset of processes first affected by the fault with 80% accuracy and 70% accuracy, respectively and the code region where where the fault first manifested with 90% and 50% accuracy, respectively.

Bronevetsky, G; Laguna, I; Bagchi, S; de Supinski, B R; Ahn, D; Schulz, M

2010-03-23

298

Skill-based differences in option generation in a complex task: a verbal protocol analysis.  

PubMed

In recent models of decision-making, cognitive scientists have examined the relationship between option generation and successful performance. These models suggest that those who are successful at decision-making generate few courses of action and typically choose the first, often best, option. Scientists working in the area of expert performance, on the other hand, have demonstrated that the ability to generate and prioritize task-relevant options during situation assessment is associated with successful performance. In the current study, we measured law enforcement officers' performance and thinking in a simulated task environment to examine the option generation strategies used during decision-making in a complex domain. The number of options generated during assessment (i.e., making decisions about events in the environment) and intervention (i.e., making decisions about personal courses of action) phases of decision-making interact to produce a successful outcome. The data are explained with respect to the development of a situational representation and long-term working memory skills capable of supporting both option generation processes. PMID:21461753

Ward, Paul; Suss, Joel; Eccles, David W; Williams, A Mark; Harris, Kevin R

2011-08-01

299

AMEE Medical Education Guide No. 7. Task-Based Learning: An Educational Strategy for Undergraduate, Postgraduate and Continuing Medical Education, Part 1.  

ERIC Educational Resources Information Center

Task-based learning (TBL) is an educationally sound, effective, and efficient strategy for delivering relevant education. In TBL, the tasks of the health care professional provide the context and the focus for learning, but are not the objective of the student's learning. Students gain a basic understanding of the principles of health and disease…

Harden, R. M.; And Others

1996-01-01

300

The Development and Implementation of a Web-Based Formative Peer Assessment System for Enhancing Students' Metacognitive Awareness and Performance in Ill-Structured Tasks  

ERIC Educational Resources Information Center

An assessment was conducted of a web-based formative peer assessment system (WFPAS) emphasizing learners' metacognitive awareness for their performance in ill-structured tasks. Results indicate that the WFPAS group achieved significantly higher scores for metacognitive awareness and performance in ill-structured tasks than the traditional…

Kim, Minjeong; Ryu, Jeeheon

2013-01-01

301

Classification effects of real and imaginary movement selective attention tasks on a P300-based brain-computer interface.  

PubMed

Brain-computer interfaces (BCIs) rely on various electroencephalography methodologies that allow the user to convey their desired control to the machine. Common approaches include the use of event-related potentials (ERPs) such as the P300 and modulation of the beta and mu rhythms. All of these methods have their benefits and drawbacks. In this paper, three different selective attention tasks were tested in conjunction with a P300-based protocol (i.e. the standard counting of target stimuli as well as the conduction of real and imaginary movements in sync with the target stimuli). The three tasks were performed by a total of 10 participants, with the majority (7 out of 10) of the participants having never before participated in imaginary movement BCI experiments. Channels and methods used were optimized for the P300 ERP and no sensory-motor rhythms were explicitly used. The classifier used was a simple Fisher's linear discriminant. Results were encouraging, showing that on average the imaginary movement achieved a P300 versus No-P300 classification accuracy of 84.53%. In comparison, mental counting, the standard selective attention task used in previous studies, achieved 78.9% and real movement 90.3%. Furthermore, multiple trial classification results were recorded and compared, with real movement reaching 99.5% accuracy after four trials (12.8 s), imaginary movement reaching 99.5% accuracy after five trials (16 s) and counting reaching 98.2% accuracy after ten trials (32 s). PMID:20811088

Salvaris, Mathew; Sepulveda, Francisco

2010-10-01

302

An agent-based model of exposure to human toxocariasis: a multi-country validation.  

PubMed

Seroprevalence data illustrate that human exposure to Toxocara is frequent. Environmental contamination with Toxocara spp. eggs is assumed to be the best indicator of human exposure, but increased risk of exposure has also been associated with many other factors. Reported associations are inconsistent, however, and there is still ambiguity regarding the factors driving the onset of Toxocara antibody positivity. The objective of this work was to assess the validity of our current conceptual understanding of the key processes driving human exposure to Toxocara. We constructed an agent-based model predicting Toxocara antibody positivity (as a measure of exposure) in children. Exposure was assumed to depend on the joint probability of 3 parameters: (1) environmental contamination with Toxocara spp. eggs, (2) larvation of these eggs and (3) the age-related contact with these eggs. This joint probability was linked to processes of acquired humoral immunity, influencing the rate of antibody seroreversion. The results of the simulation were validated against published data from 5 different geographical settings. Using simple rules and a stochastic approach with parameter estimates derived from the respective contexts, plausible serological patterns emerged from the model in nearly all settings. Our approach leads to novel insights in the transmission dynamics of Toxocara. PMID:23574630

Kanobana, K; Devleesschauwer, B; Polman, K; Speybroeck, N

2013-07-01

303

Comparative analysis of UVB exposure between Nimbus 7/TOMS satellite estimates and ground-based measurements  

NASA Astrophysics Data System (ADS)

This study describes the patterns of variation in ultraviolet (UV) exposure across time and space using two continental scale data sets on UV radiation and conducts a comparative analysis of two sources of noontime UV-B exposure data across the continental US. One dataset was collected from 37 ground-based stations equipped with broadband UV-B-1 Pyranometers across North America whereas the other dataset was of synchronous satellite data collected from the Nimbus-7/TOMS sensor. Comparisons of these datasets confirmed agreement between the ground-based measurements and the TOMS satellite estimates with correlation coefficients of 0.87 and 0.95 for daily and monthly UV Index time series (i.e., a common metric of UV radiation exposure), respectively.

Gao, Zhiqiang; Gao, Wei

2010-08-01

304

Template-based approach for detecting motor task activation-related hyperperfusion in pulsed ASL data.  

PubMed

Arterial spin labeling (ASL) permits the noninvasive measurement of quantitative values of cerebral blood flow (CBF) and is thus well adapted to study inter- and intrasubject perfusion variations whether at rest or during an fMRI task. In this study, a template approach to detect brain activation as a CBF difference between resting and activated groups was compared with a standard generalized linear model (GLM) analysis. A basal perfusion template of PICORE-Q2TIPS ASL images acquired at 3T from a group of 25 healthy subjects (mean age 31.6 ± 8.3 years) was created. The second group of 12 healthy subjects (mean age 28.6 ± 2.7 years) performed a block-design motor task. The template was compared with the mean activated image of the second group both at the individual and at the group level to extract activation maps. The results obtained using a GLM analysis of the whole sequence was used as ground truth for comparison. The influences of spatial normalization using DARTEL registration and of correction of partial volume effects (PVE) in the construction of the template were assessed. Results showed that a basal perfusion template can detect activation-related hyperperfusion in motor areas. The true positive ratio was increased by 2.5% using PVE-correction and by 3.2% using PVE-correction with DARTEL registration. On average, the group comparison presented a 2.2% higher true positive ratio than the one-to-many comparison. PMID:23408457

Petr, Jan; Ferré, Jean-Christophe; Raoult, Hélène; Bannier, Elise; Gauvrit, Jean-Yves; Barillot, Christian

2014-04-01

305

Sun exposure behaviour among subgroups of the Danish population. Based on personal electronic UVR dosimetry and corresponding exposure diaries.  

PubMed

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 received a significantly higher UVR dose than boys due to more days with risk behaviour (sunbathing or exposing shoulders outdoors). This exposure pattern, with females having more risk behaviour than males, was also found among adolescents and adults. Sunbathing or exposing shoulders (risk behaviour) outside the beach resulted in a median of 2.5 SED per day in northern Europe and 3.2 SED per day in southern Europe, while the corresponding values were 4.6 SED and 6.9 SED per day at the beach. UVR doses above 10 SED per day were connected with risk behaviour. The subjects had a median of 13 days with risk behaviour (range, 0-93 days). The subjects used sunscreen on a median of five days (range, 0-130 days), but have a median of seven days with risk behaviour without sunscreen applied (range, 0-47 days). They had a median of one sunburn per sun-year (range 0-10). Fifty percent of the UVR dose was received between 12.00 and 15.00. Only the gardeners received the main part of their UVR dose on workdays. Conclusions : - High UVR doses are connected with risk behaviour. Reduction of cumulative lifetime UVR dose could be obtained by minimizing risk behaviour. - Sunburns were highly correlated to risk behaviour. - Use of sunscreen correlated with days "sunbathing with the intention to tan", indicating that sunscreens were used to avoid sunburn during risk behaviour. - Scheduling lunch breaks and other breaks indoors at noon, where ambient UVR peaks, could reduce the occupational UVR exposure significantly. - In the winter-half-year in Denmark. the UVR dose received from solar exposure is negligible and no UVR precautions are needed. This study documented that high subject compliance rate and data reliability could be obtained in long-time UVR dosimeter study as ours by being service minded but persistent, offering dosimeter maintenance service within 24 hours and scrutinizing data for errors and mistakes just after data collection. PMID:18321444

Thieden, Elisabeth

2008-02-01

306

Student Off-Task Behavior in Computer-Based Learning in the Philippines: Comparison to Prior Research in the USA  

ERIC Educational Resources Information Center

Background: Off-task behavior can be defined as any behavior that does not involve the learning task or material, or where learning from the material is not the primary goal. One suggested path for understanding how to address off-task behavior is to study classrooms where off-task behavior is less common, particularly in Asia, in order to…

Rodrigo, Ma. Mercedes T.; Baker, Ryan S. J. D.; Rossi, Lisa

2013-01-01

307

Separation of fission products based on ionic liquids: Task-specific ionic liquids containing an aza-crown ether fragment  

SciTech Connect

A new class of task-specific ionic liquids (TSILs) based on the covalent attachment of imidazolium cations to a monoaza-crown ether fragment has been synthesized and characterized. The efficacy of these TSILs for the biphasic extraction of Cs(+) and Sr(2+) from aqueous solutions has been evaluated. The extraction properties of these TSILs can be influenced by the structures of the covalently attached imidazolium cations, which highlight the possibilities to enhance or tune the selectivities of crown ethers toward target ionic species through the covalent coupling with the imidazolium cations. (c) 2005 Elsevier B.V. All rights reserved.

Luo, Huimin [ORNL] [ORNL; Dai, Sheng [ORNL] [ORNL; Bonnesen, Peter V [ORNL] [ORNL; Buchanan III, A C [ORNL] [ORNL

2005-01-01

308

POTENTIAL INHALATION EXPOSURE TO VOLATILE CHEMICALS IN WATER-BASED HARD-SURFACE CLEANERS  

EPA Science Inventory

Potential inhalation exposure of building occupants to volatile chemicals in water-based hard-surface cleaners was evaluated by analyzing 267 material safety data sheets (MSDSs). Among the 154 chemicals reported, 44 are volatile or semi-volatile. Hazardous air pollutants (HAPs) r...

309

Aggression and Violence Exposure in Adolescence and the Role of School-Based Policy Initiatives  

ERIC Educational Resources Information Center

This article reports on an exploratory study into young people's exposure to aggression and violence. It undertakes a collective examination of the domains occupied by young people and in doing so focuses on an area that has for the most part been overlooked by previous researchers in the UK. The analysis is based on the responses of 98 young…

Kennedy, Anne

2011-01-01

310

Work Characteristics and Pesticide Exposures among Migrant Agricultural Families: A Community-Based Research Approach  

Microsoft Academic Search

There are few data on pesticide exposures of migrant Latino farmworker children, and access to this vulnerable population is often difficult. In this paper we describe a community-based approach to implement culturally appropriate research methods with a migrant Latino farm- worker community in Oregon. Assessments were conducted in 96 farmworker homes and 24 grower homes in two agricultural communities in

Linda A. McCauley; Michael R. Lasarev; Gregory Higgins; Joan Rothlein; Juan Muniz; Caren Ebbert; Jacki Phillips

2001-01-01

311

Modifying Exposure-Based CBT for Cambodian Refugees with Posttraumatic Stress Disorder  

ERIC Educational Resources Information Center

Cambodian refugees represent a severely traumatized population living in the United States. In this paper, we describe the modification of a cognitive-behavior therapy program to facilitate delivery of an exposure-based treatment for posttraumatic stress disorder while addressing some of the challenges brought by differences in language and…

Otto, Michael W.; Hinton, Devon E.

2006-01-01

312

An Integrated Web-Based Assessment Tool for Assessing Pesticide Exposure and Risks  

EPA Science Inventory

Background/Question/Methods We have created an integrated web-based tool designed to estimate exposure doses and ecological risks under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Endangered Species Act. This involved combining a number of disparat...

313

The Roles of Timing and Task Order during Task Switching  

Microsoft Academic Search

The neural bases of the different processes involved in task switching remain poorly identified. Whether distinct brain regions are involved according to the overall structure of the task sequence and the predictability of task timing during task switching is unknown. To address this question, we used functional magnetic resonance imaging and a 2 × 2 factorial design varying timing (fixed\\/random)

Jean-Claude Dreher; Etienne Koechlin; Syed Omar Ali; Jordan Grafman

2002-01-01

314

ATTRIBUTION OF PARTICLE EXPOSURE AND RISK TO COMBUSTION SOURCE EMISSIONS BASED ON PERSONAL PAH EXPOSURE AND URINARY METABOLITES  

EPA Science Inventory

Personal airborne exposures to carcinogenic particulate PAH have been significantly correlated with exposure to respirable fine particle mass (PM 2.5) in several studies. All combustion sources emit PAH, however the relative concentrations of different PAH and other organic tr...

315

Noise exposure reconstruction and evaluation of exposure trends in two large automotive plants.  

PubMed

This study used a task-based approach to reconstruct employee noise exposures at two large automotive manufacturing plants for the period 1970-1989, utilizing historic noise measurement data, work history records, documented changes in plant operations, focus group discussions, structured interviews with long-tenure employees, and task-based job profiles. Task-based job noise exposure profiles were developed in the 1990s when the plants conducted task-based noise monitoring. Under the assumption that tasks and time-at-task profile within jobs did not change over time, these profiles were applied to historic jobs. By linking historic noise exposure measurements to job tasks, this approach allowed task-based reconstructed noise exposure profiles to capture variability of daily noise exposures. Reconstructed noise exposures, along with task-based noise exposure measurements collected at each plant during the 1990s, were analyzed to examine time trends in workplace noise levels and worker noise exposure. Our analysis of noise exposure trends revealed that noise levels for many jobs declined by ?3 dBA from 1970 to 1998 as operational and equipment changes occurred in the plants and some noise control measures were implemented, but for some jobs, noise levels increased in the mid- to late 1990s, most likely because of an increase in production at that time. Overall, the percentage of workers exposed to noise levels >90 dBA decreased from 95% in 1970 to 54% in 1998 at one of the plants and decreased from 36% in 1970 to ~5% in 1999 at the other plant. These reductions indicate a degree of success for the hearing conservation program. However, the actual number of employees with noise exposure >90 dBA increased because of a substantial increase in the number of production employees, particularly in jobs with high noise levels, which shows a hearing conservation program challenge that companies face during periods of increased production. Future analysis of hearing levels in these plant populations will help determine whether noise level reduction translates into decreased hearing loss at these plants. PMID:23852046

Brueck, Scott E; Prince Panaccio, Mary; Stancescu, Daniel; Woskie, Susan; Estill, Cheryl; Waters, Martha

2013-11-01

316

Occupational exposure to asbestos and lung cancer in men: evidence from a population-based case-control study in eight Canadian provinces  

PubMed Central

Background Asbestos is classified as a human carcinogen, and studies have consistently demonstrated that workplace exposure to it increases the risk of developing lung cancer. Few studies have evaluated risks in population-based settings where there is a greater variety in the types of occupations, and exposures. Methods This was a population based case–control study with 1,681 incident cases of lung cancer, and 2,053 controls recruited from 8 Canadian provinces between 1994 and 1997. Self-reported questionnaires were used to elicit a lifetime occupational history, including general tasks, and information for other risk factors. Occupational hygienists, who were blinded to case–control status, assigned asbestos exposures to each job on the basis of (i) concentration (low, medium, high), (ii) frequency (<5%, 5-30%, and >30% of the time in a normal work week), and (iii) reliability (possible, probable, definite). Logistic regression was used to estimate odds ratios (ORs) and their corresponding 95% confidence intervals (CI). Results Those occupationally exposed to (i) low, and (ii) medium or high concentrations of asbestos had ORs for lung cancer of 1.17 (95% CI=0.92 – 1.50) and 2.16 (95% CI=1.21-3.88), respectively, relative to those who were unexposed. Medium or high exposure to asbestos roughly doubled the risk for lung cancer across all three smoking pack-year categories. The joint relationship between smoking and asbestos was consistent with a multiplicative risk model. Conclusions Our findings provide further evidence that exposure to asbestos has contributed to an increased risk of lung cancer in Canadian workplaces, and suggests that nearly 3% of lung cancers among Canadian men are caused by occupational exposure to asbestos. PMID:23234401

2012-01-01

317

Double-exposure phase calculation method in electronic speckle pattern interferometry based on holographic object illumination  

NASA Astrophysics Data System (ADS)

Multiple-exposure phase calculation procedures are widely used in electronic speckle pattern interferometry to calculate phase maps of displacements. We developed a double-exposure process based on holographic illumination of the object and the idea of the spatial carrier phase-shifting method to examine transient displacements. In our work, computer-generated holograms and a spatial light modulator were used to generate proper coherent illuminating masks. In this adjustment all phase-shifted states were at our disposal from one recorded speckle image for phase calculation. This technique can be used in the large scale of transient measurements. In this paper we illustrate the principle through several examples.

Séfel, Richárd; Kornis, János

2011-08-01

318

An integrated exposure/pharmacokinetic based approach to the assessment of complex exposures. Lead: a case study  

SciTech Connect

A problem in evaluating the hazard represented by an environmental toxicant is that exposures can occur via multiple media such as water, land, and air. Lead is one of the toxicants of concern that has been associated with adverse effects on heme metabolism, serum vitamin D levels, and the mental and physical development of infants and children exposed at very low environmental levels. Effects of lead on development are particularly disturbing in that the consequences of early delays or deficits in physical or mental development may have long-term consequences over the lifetime of affected individuals. Experimental and epidemiologic studies have indicated that blood lead levels in the range of 10-15 micrograms/dl, or possibly lower, are likely to produce subclinical toxicity. Since a discernible threshold has not been demonstrated, it is prudent to preclude development of a Reference Dose (RfD) for lead. As an alternate, the U.S. Environmental Protection Agency (U.S. EPA) has developed the uptake/biokinetic lead model that provides a means for evaluating the relative contribution of various media to establishing blood lead levels in children. This approach will allow for the identification of site- and situation-specific abatement strategies based on projected blood lead levels in vulnerable human populations exposed to lead in air, diet, water, soil/dust, and paint; thus making it possible to evaluate regulatory decisions concerning each medium on blood levels and potential health effects.35 references.

DeRosa, C.T.; Choudhury, H.; Peirano, W.B. (Environmental Criteria and Assessment Office, U.S. Environmental Protection Agency, Cincinnati, OH (United States))

1991-07-01

319

A comparison of mindfulness, nonjudgmental, and cognitive dissonance-based approaches to mirror exposure  

Microsoft Academic Search

This study compares different versions of mirror exposure (ME), a body image intervention with research support. ME protocols were adapted to maximize control and comparability, and scripted for delivery by research assistants. Female undergraduates (N=168) were randomly assigned to receive mindfulness-based (MB; n=58), nonjudgmental (NJ; n=55), or cognitive dissonance-based (CD, n=55) ME. Participants completed the Body Image Avoidance Questionnaire (BIAQ),

Cynthia A. Luethcke; Leda McDaniel; Carolyn Black Becker

2011-01-01

320

Human exposure to radio base-station antennas in urban environment  

Microsoft Academic Search

In this paper, the human exposure to the electromagnetic field radiated by a radio base-station antenna operating around 900 MHz in an urban environment has been analyzed. A hybrid ray-tracing\\/finite-difference time-domain (FDTD) method has been used to evaluate the incident field and the power absorbed in an exposed subject in the presence of reflecting walls. The base-station antenna has been

Paolo Bernardi; Marta Cavagnaro; Stefano Pisa; Emanuele Piuzzi

2000-01-01

321

Biologically based modeling of multimedia, multipathway, multiroute population exposures to arsenic  

PubMed Central

This article presents an integrated, biologically based, source-to-dose assessment framework for modeling multimedia/multipathway/multiroute exposures to arsenic. Case studies demonstrating this framework are presented for three US counties (Hunderton County, NJ; Pima County, AZ; and Franklin County, OH), representing substantially different conditions of exposure. The approach taken utilizes the Modeling ENvironment for TOtal Risk studies (MENTOR) in an implementation that incorporates and extends the approach pioneered by Stochastic Human Exposure and Dose Simulation (SHEDS), in conjunction with a number of available databases, including NATA, NHEXAS, CSFII, and CHAD, and extends modeling techniques that have been developed in recent years. Model results indicate that, in most cases, the food intake pathway is the dominant contributor to total exposure and dose to arsenic. Model predictions are evaluated qualitatively by comparing distributions of predicted total arsenic amounts in urine with those derived using biomarker measurements from the NHEXAS — Region V study: the population distributions of urinary total arsenic levels calculated through MENTOR and from the NHEXAS measurements are in general qualitative agreement. Observed differences are due to various factors, such as interindividual variation in arsenic metabolism in humans, that are not fully accounted for in the current model implementation but can be incorporated in the future, in the open framework of MENTOR. The present study demonstrates that integrated source-to-dose modeling for arsenic can not only provide estimates of the relative contributions of multipathway exposure routes to the total exposure estimates, but can also estimate internal target tissue doses for speciated organic and inorganic arsenic, which can eventually be used to improve evaluation of health risks associated with exposures to arsenic from multiple sources, routes, and pathways. PMID:18073786

Georgopoulos, Panos G.; Wang, Sheng-Wei; Yang, Yu-Ching; Xue, Jianping; Zartarian, Valerie G.; Mccurdy, Thomas; Ozkaynak, Haluk

2011-01-01

322

Developing Respondent Based Multi-Media Measures of Exposure to Sexual Content  

PubMed Central

Despite the interest in the effects of the media on sexual behavior, there is no single method for assessing exposure to a particular type of media content (e.g., sex). This paper discusses the development of six sexual content exposure measures based on adolescents’ own subjective ratings of the sexual content in titles in 4 media (i.e., television, music, magazines, videogames). We assessed the construct and criterion validity of these measures by examining the associations among each of these measures of exposure to sexual content as well as their associations with adolescents’ sexual activity. Data were collected in summer 2005 through a web-based survey using a quota sample of 547 youth aged 14–16 from the Philadelphia area. Adolescents rated how often they were exposed to specific television shows, magazine titles, etc. on 4-point never to often scales. They also rated the sexual content of those titles on 4-point no sexual content to a lot of sexual content scales. Sexual behavior was measured using an ordered index of lifetime pre-coital and coital sexual activity. The strength of association between exposure to sexual content and sexual activity varied by medium and measure. Based on our findings, we recommend the use of a multiple media weighted sum measure. This measure produces findings that are consistent with those of similar studies. PMID:20411048

Bleakley, Amy; Fishbein, Martin; Hennessy, Michal; Jordan, Amy; Chernin, Ariel; Stevens, Robin

2010-01-01

323

Task Analysis: A Proactive Paradigm.  

ERIC Educational Resources Information Center

A sequential and developmental curriculum design is conceptualized, based on task analysis. Task analysis is a detailed inquiry into actions undertaken in performing specific tasks or jobs. Baseline data form a database on which education and training programs are designed, produced, and evaluated. The following are sources of information for task

Cipriano, Robert E.

324

A residue-based toxicokinetic model for pulse-exposure toxicity in aquatic systems  

SciTech Connect

This pulse-exposure model (PULSETOX) is based on the simple one-compartment first-order kinetics (1CFOK) equation. It tracks the accumulation of waterborne organic chemicals by fish and predicts acute toxicity by means of previously established relationships between whole-body residues and lethality. The predictive capabilities of the model were tested with a data set of 27 acute pulse-exposure lethality tests with larval fathead minnows (Pimephales promelas) exposed to pentachlorophenol (PCP). Tests included eight single exposures (2 to 96 h) and 19 multiple exposures, which varied in the number (2 to 15) and duration (2 to 24 h) of pulses, and time interval between pulses (6 to 24 h). Experimental work included determination of 1CFOK kinetics parameters from [{sup 14}C]PCP uptake and clearance, and from time-toxicity curves. Lethality was expected in any exposure regime where the fish reaches or exceeds the critical body residue (CBR) of 0.30 mmol PCP/kg fish (SD, {+-} 0.02; n = 11). Using the CBR endpoint, the model accounted for between 90 and 93% of variability in the observed lethality data, depending on the toxicokinetic parameters employed. Predictive power of the model was optimized by using kinetics parameters derived from the toxicity curve for pulse-toxicity tests as shown by the regression: predicted LC50 = 1.04 {center_dot} (observed LC50) + 0.01 (p < 0.001, r{sup 2} = 0.94, n = 27).

Hickie, B.E. [Trent Univ., Peterborough, Ontario (Canada). Environmental Resource Studies Program; McCarty, L.S. [L.S. McCarty Scientific Research and Consulting, Oakville, Ontario (Canada); Dixon, D.G. [Univ. of Waterloo, Ontario (Canada). Dept. of Biology

1995-12-01

325

Sinonasal Cancer and Occupational Exposure in a Population-Based Registry  

PubMed Central

We examined occupational exposures among subjects with sinonasal cancer (SNC) recorded in a population-based registry in the Lombardy Region, the most populated and industrialized Italian region. The registry collects complete clinical information and exposure to carcinogens regarding all SNC cases occurring in the population of the region. In the period 2008–2011, we recorded 210 SNC cases (137 men, 73 women). The most frequent occupational exposures were to wood (44 cases, 21.0%) and leather dust (29 cases, 13.8%), especially among men: 39 cases (28.5%) to wood and 23 cases (16.8%) to leather dust. Exposure to other agents was infrequent (<2%). Among 62 subjects with adenocarcinoma, 50% had been exposed to wood dust and 30.7% to leather dust. The proportions were around 10% in subjects with squamous cell carcinoma and about 20% for tumors with another histology. The age-standardized rates (×100,000 person-years) were 0.7 in men and 0.3 in women. Complete collection of cases and their occupational history through a specialized cancer registry is fundamental to accurately monitor SNC occurrence in a population and to uncover exposure to carcinogens in different industrial sectors, even those not considered as posing a high risk of SNC, and also in extraoccupational settings. PMID:24082884

Mensi, Carolina; Sieno, Claudia; Riboldi, Luciano; Bertazzi, Pier Alberto

2013-01-01

326

Exposure assessment in front of a multi-band base station antenna.  

PubMed

This study investigates occupational exposure to electromagnetic fields in front of a multi-band base station antenna for mobile communications at 900, 1800, and 2100?MHz. Finite-difference time-domain method was used to first validate the antenna model against measurement results published in the literature and then investigate the specific absorption rate (SAR) in two heterogeneous, anatomically correct human models (Virtual Family male and female) at distances from 10 to 1000?mm. Special attention was given to simultaneous exposure to fields of three different frequencies, their interaction and the additivity of SAR resulting from each frequency. The results show that the highest frequency--2100?MHz--results in the highest spatial-peak SAR averaged over 10?g of tissue, while the whole-body SAR is similar at all three frequencies. At distances > 200?mm from the antenna, the whole-body SAR is a more limiting factor for compliance to exposure guidelines, while at shorter distances the spatial-peak SAR may be more limiting. For the evaluation of combined exposure, a simple summation of spatial-peak SAR maxima at each frequency gives a good estimation for combined exposure, which was also found to depend on the distribution of transmitting power between the different frequency bands. PMID:21365667

Kos, Bor; Vali?, Blaž; Kotnik, Tadej; Gajšek, Peter

2011-04-01

327

Teaching computer-based spelling to individuals with developmental and hearing disabilities: transfer of stimulus control to writing tasks.  

PubMed Central

Computer-based instruction may yield widely useful handwritten spelling. Illustrative cases involved individuals with mental retardation and hearing impairments. The participant in Study 1 matched computer pictures and printed words to one another but did not spell the words to pictures. Spelling was then taught using a computerized procedure. In general, increases in the accuracy of computer spelling were accompanied by improvements in written spelling to pictures. Study 2 extended these results with a 2nd participant. After initial training, spelling improved in the context of a retrieval task in which the participant (a) wrote a list of the names of objects displayed on a table, (b) selected the objects from a shelf, and (c) returned the objects to the table. Nearly perfect accuracy scores declined on some retrieval trials conducted without a list, suggesting that the list may have served a mediating function during retrieval. Transfer of stimulus control of computer-based teaching to the retrieval task may have been attributable to the existence of stimulus classes involving pictures, objects, and printed words. Images Figure 1 Figure 3 PMID:8881342

Stromer, R; Mackay, H A; Howell, S R; McVay, A A; Flusser, D

1996-01-01

328

Based on Regular Expression Matching of Evaluation of the Task Performance in WSN: A Queue Theory Approach  

PubMed Central

Due to the limited resources of wireless sensor network, low efficiency of real-time communication scheduling, poor safety defects, and so forth, a queuing performance evaluation approach based on regular expression match is proposed, which is a method that consists of matching preprocessing phase, validation phase, and queuing model of performance evaluation phase. Firstly, the subset of related sequence is generated in preprocessing phase, guiding the validation phase distributed matching. Secondly, in the validation phase, the subset of features clustering, the compressed matching table is more convenient for distributed parallel matching. Finally, based on the queuing model, the sensor networks of task scheduling dynamic performance are evaluated. Experiments show that our approach ensures accurate matching and computational efficiency of more than 70%; it not only effectively detects data packets and access control, but also uses queuing method to determine the parameters of task scheduling in wireless sensor networks. The method for medium scale or large scale distributed wireless node has a good applicability.

Cui, Kai; Zhou, Kuanjiu; Yu, Yanshuo

2014-01-01

329

Based on Regular Expression Matching of Evaluation of the Task Performance in WSN: A Queue Theory Approach.  

PubMed

Due to the limited resources of wireless sensor network, low efficiency of real-time communication scheduling, poor safety defects, and so forth, a queuing performance evaluation approach based on regular expression match is proposed, which is a method that consists of matching preprocessing phase, validation phase, and queuing model of performance evaluation phase. Firstly, the subset of related sequence is generated in preprocessing phase, guiding the validation phase distributed matching. Secondly, in the validation phase, the subset of features clustering, the compressed matching table is more convenient for distributed parallel matching. Finally, based on the queuing model, the sensor networks of task scheduling dynamic performance are evaluated. Experiments show that our approach ensures accurate matching and computational efficiency of more than 70%; it not only effectively detects data packets and access control, but also uses queuing method to determine the parameters of task scheduling in wireless sensor networks. The method for medium scale or large scale distributed wireless node has a good applicability. PMID:25401151

Wang, Jie; Cui, Kai; Zhou, Kuanjiu; Yu, Yanshuo

2014-01-01

330

The Importance of the Secure Base Effect for Domestic Dogs - Evidence from a Manipulative Problem-Solving Task  

PubMed Central

Background It has been suggested that dogs display a secure base effect similar to that found in human children (i.e., using the owner as a secure base for interacting with the environment). In children, this effect influences their daily lives and importantly also their performance in cognitive testing. Here, we investigate the importance of the secure base effect for dogs in a problem-solving task. Methodology/Principal Findings Using a manipulative task, we tested dogs in three conditions, in which we varied the owner's presence and behavior (Experiment 1: “Absent owner”, “Silent owner”, “Encouraging owner”) and in one additional condition, in which the owner was replaced by an unfamiliar human (Experiment 2: “Replaced owner”). We found that the dogs' duration of manipulating the apparatus was longer when their owner was present than absent, irrespective of the owner's behavior. The presence of an unfamiliar human however did not increase their manipulation. Furthermore, the reduced manipulation during the absence of the owner was not correlated with the dog's degree of separation distress scored in a preceding attachment experiment. Conclusions/Significance Our study is the first to provide evidence for an owner-specific secure base effect in dogs that extends from attachment tests to other areas of dogs' lives and also manifests itself in cognitive testing – thereby confirming the remarkable similarity between the secure base effect in dogs and in human children. These results also have important implications for behavioral testing in dogs, because the presence or absence of the owner during a test situation might substantially influence dogs' motivation and therefore the outcome of the test. PMID:23734243

Horn, Lisa; Huber, Ludwig; Range, Friederike

2013-01-01

331

Genetic Programming-based Construction of Features for Machine Learning and Knowledge Discovery Tasks  

Microsoft Academic Search

In this paper we use genetic programming for changing the representation of the input data for machine learners. In particular, the topic of interest here is feature construction in the learning- from-examples paradigm, where new features are built based on the original set of attributes. The paper first introduces the general framework for GP-based feature construction. Then, an extended approach

Krzysztof Krawiec

2002-01-01

332

Increase in physical activities in kindergarten children with cerebral palsy by employing MaKey-MaKey-based task systems.  

PubMed

In this study, we employed Flash- and Scratch-based multimedia by using a MaKey-MaKey-based task system to increase the motivation level of children with cerebral palsy to perform physical activities. MaKey MaKey is a circuit board that converts physical touch to a digital signal, which is interpreted by a computer as a keyboard message. In this study, we used conductive materials to control this interaction. This study followed single-case design using ABAB models in which A indicated the baseline and B indicated the intervention. The experiment period comprised 1 month and a half. The experimental results demonstrated that in the case of two kindergarten children with cerebral palsy, their scores were considerably increased during the intervention phrases. The developmental applications of the results are also discussed. PMID:24864049

Lin, Chien-Yu; Chang, Yu-Ming

2014-09-01

333

Attentional spreading to task-irrelevant object features: experimental support and a 3-step model of attention for object-based selection and feature-based processing modulation  

PubMed Central

Directing attention to a specific feature of an object has been linked to different forms of attentional modulation. Object-based attention theory founds on the finding that even task-irrelevant features at the selected object are subject to attentional modulation, while feature-based attention theory proposes a global processing benefit for the selected feature even at other objects. Most studies investigated either the one or the other form of attention, leaving open the possibility that both object- and feature-specific attentional effects do occur at the same time and may just represent two sides of a single attention system. We here investigate this issue by testing attentional spreading within and across objects, using reaction time (RT) measurements to changes of attended and unattended features on both attended and unattended objects. We asked subjects to report color and speed changes occurring on one of two overlapping random dot patterns (RDPs), presented at the center of gaze. The key property of the stimulation was that only one of the features (e.g., motion direction) was unique for each object, whereas the other feature (e.g., color) was shared by both. The results of two experiments show that co-selection of unattended features even occurs when those features have no means for selecting the object. At the same time, they demonstrate that this processing benefit is not restricted to the selected object but spreads to the task-irrelevant one. We conceptualize these findings by a 3-step model of attention that assumes a task-dependent top-down gain, object-specific feature selection based on task- and binding characteristics, and a global feature-specific processing enhancement. The model allows for the unification of a vast amount of experimental results into a single model, and makes various experimentally testable predictions for the interaction of object- and feature-specific processes. PMID:24959132

Wegener, Detlef; Galashan, Fingal Orlando; Aurich, Maike Kathrin; Kreiter, Andreas Kurt

2014-01-01

334

Autonomous cooperation of heterogeneous platforms for sea-based search tasks  

E-print Network

Many current methods of search using autonomous marine vehicles do not adapt to changes in mission objectives or the environment. A cellular-decomposition-based framework for cooperative, adaptive search is proposed that ...

Shafer, Andrew J., M. Eng. Massachusetts Institute of Technology

2008-01-01

335

Genetic Programming-based Construction of Features for Machine Learning and Knowledge Discovery Tasks  

Microsoft Academic Search

In this paper we use genetic programming for changing the representation of the input data for machine learners. In particular, the topic of interest here is feature construction in the learning-from-examples paradigm, where new features are built based on the original set of attributes. The paper first introduces the general framework for GP-based feature construction. Then, an extended approach is

Krzysztof Krawiec

2002-01-01

336

The Precautionary Principle in the Context of Mobile Phone and Base Station Radiofrequency Exposures  

PubMed Central

Background No health hazard has been established from exposure to radiofrequency fields up to the levels recommended by the International Commission on Non-Ionizing Radiation Protection. However, in response to public concern and the perceived level of scientific uncertainty, there are continuing calls for the application of the precautionary principle to radiofrequency exposures from mobile phones and base stations. Objective We examined the international evolution of calls for precautionary measures in relation to mobile phones and base stations, with particular focus on Australia and the United Kingdom. Results The precautionary principle is difficult to define, and there is no widespread agreement as to how it should be implemented. However, there is a strong argument that precautionary measures should not be implemented in the absence of reliable scientific data and logical reasoning pointing to a possible health hazard. There is also experimental evidence that precautionary advice may increase public concern. Conclusion We argue that conservative exposure standards, technical features that minimize unnecessary exposures, ongoing research, regular review of standards, and availability of consumer information make mobile communications inherently precautionary. Commonsense measures can be adopted by individuals, governments, and industry to address public concern while ensuring that mobile networks are developed for the benefit of society. PMID:19750093

Dolan, Mike; Rowley, Jack

2009-01-01

337

A liquid crystal-based passive badge for personal monitoring of exposure to hydrogen sulfide.  

PubMed

A new liquid crystal (LC)-based passive dosimeter badge for personal monitoring of exposure to hydrogen sulfide (H2S) gas is reported. When a thin film of LC supported on a surface functionalized with lead perchlorate Pb(ClO4)2 (the LC sensor) is exposed to H2S, the orientation of LC molecules in the film changes from perpendicular to parallel. This reorientation induces a change in the appearance of the LC film when viewed between crossed polarizers. A H2S dosimeter was fabricated by pairing a LC sensor with a glass substrate forming a headspace between the two surfaces, to control diffusion of H2S across the LC film. When the dosimeter is exposed to H2S, a bright front appears as a function of exposure time. An algorithm has been developed to correlate this response length and exposure dose. The dosimeters are functionally stable when subjected to extreme temperature and humidity fluctuations, and are immune to a number of potentially interfering chemicals, except mercaptans. These dosimeters detect H2S at 0.2 ppm TWA (8 hr) with ±20% overall accuracy. The dosimeters were used to monitor the personal exposure of personnel working in an oil refinery. The TWA concentrations measured by the LC-based dosimeters correlate strongly with the NIOSH 1063 method that uses a sorbent tube and a pump followed by laboratory analysis. Thus, the LC-based dosimeters can provide a sensitive tool for on-site assessment of personal exposure to H2S in different environments. PMID:24766440

Robinson, Sheila E; Grinwald, Bart A; Bremer, Laura L; Kupcho, Kurt A; Acharya, Bharat R; Owens, Patrick D

2014-11-01

338

A GIS-based method for household recruitment in a prospective pesticide exposure study  

PubMed Central

Background Recent advances in GIS technology and remote sensing have provided new opportunities to collect ecologic data on agricultural pesticide exposure. Many pesticide studies have used historical or records-based data on crops and their associated pesticide applications to estimate exposure by measuring residential proximity to agricultural fields. Very few of these studies collected environmental and biological samples from study participants. One of the reasons for this is the cost of identifying participants who reside near study fields and analyzing samples obtained from them. In this paper, we present a cost-effective, GIS-based method for crop field selection and household recruitment in a prospective pesticide exposure study in a remote location. For the most part, our multi-phased approach was carried out in a research facility, but involved two brief episodes of fieldwork for ground truthing purposes. This method was developed for a larger study designed to examine the validity of indirect pesticide exposure estimates by comparing measured exposures in household dust, water and urine with records-based estimates that use crop location, residential proximity and pesticide application data. The study focused on the pesticide atrazine, a broadleaf herbicide used in corn production and one of the most widely-used pesticides in the U.S. Results We successfully used a combination of remotely-sensed data, GIS-based methods and fieldwork to select study fields and recruit participants in Illinois, a state with high corn production and heavy atrazine use. Our several-step process consisted of the identification of potential study fields and residential areas using aerial photography; verification of crop patterns and land use via site visits; development of a GIS-based algorithm to define recruitment areas around crop fields; acquisition of geocoded household-level data within each recruitment area from a commercial vendor; and confirmation of final participant household locations via ground truthing. The use of these procedures resulted in a sufficient sample of participants from 14 recruitment areas in seven Illinois counties. Conclusion One of the challenges in pesticide research is the identification and recruitment of study participants, which is time consuming and costly, especially when the study site is in a remote location. We have demonstrated how GIS-based processes can be used to recruit participants, increase efficiency and enhance accuracy. The method that we used ultimately made it possible to collect biological samples from a specific demographic group within strictly defined exposure areas, with little advance knowledge of the location or population. PMID:18447932

Allpress, Justine LE; Curry, Ross J; Hanchette, Carol L; Phillips, Michael J; Wilcosky, Timothy C

2008-01-01

339

Prospective memory and ageing paradox with event-based tasks: a study of young, young-old, and old-old participants.  

PubMed

Research on ageing and prospective memory--remembering to do something in the future--has resulted in paradoxical findings, whereby older adults are often impaired in the laboratory but perform significantly better than younger adults in naturalistic settings. Nevertheless, there are very few studies that have examined prospective memory both in and outside the laboratory using the same sample of young and old participants. Moreover, most naturalistic studies have used time-based tasks, and it is unclear whether the prospective memory and ageing paradox extends to event-based tasks. In this study, 72 young (18-30 years), 79 young-old (61-70 years), and 72 old-old (71-80 years) participants completed several event-based tasks in and outside the laboratory. Results showed that the ageing paradox does exist for event-based tasks but manifests itself differently from that in time-based tasks. Thus, younger adults outperformed old-old participants in two laboratory event-based tasks, but there were no age effects for a naturalistic task completed at home (remembering to write the date and time in the upper left corner of a questionnaire). The young and old-old also did not differ in remembering to retrieve a wristwatch from a pocket at the end of the laboratory session. This indicates that the paradox may be due to differences in ongoing task demands in the lab and everyday life, rather than the location per se. The findings call for a concentrated effort towards a theory of cognitive ageing that identifies the variables that do, or do not, account for this paradox. PMID:23030664

Kvavilashvili, Lia; Cockburn, Janet; Kornbrot, Diana E

2013-01-01

340

The Web as a Baseline: Evaluating the Performance of Unsupervised Web-based Models for a Range of NLP Tasks  

Microsoft Academic Search

Previous work demonstrated that web counts can be used to approximate bigram frequen- cies, and thus should be useful for a wide va- riety of NLP tasks. So far, only two gener- ation tasks (candidate selection for machine translation and confusion-set disambiguation) have been tested using web-scale data sets. The present paper investigates if these results gener- alize to tasks

Mirella Lapata; Frank Keller

2004-01-01

341

The Effectiveness of a Task-Based Instruction Program in Developing the English Language Speaking Skills of Secondary Stage Students  

ERIC Educational Resources Information Center

Communicative tasks are defined as activities in which meaning is primary, there is a goal which needs to be worked toward, there is a real world relationship and the interaction among students is the means for achieving the task outcome. However, it was assumed that adopting communicative tasks alone is not adequate as it leads the learner to…

Torky, Shaimaa Abd EL Fattah

2006-01-01

342

Welding technology transfer task/laser based weld joint tracking system for compressor girth welds  

NASA Technical Reports Server (NTRS)

Sensors to control and monitor welding operations are currently being developed at Marshall Space Flight Center. The laser based weld bead profiler/torch rotation sensor was modified to provide a weld joint tracking system for compressor girth welds. The tracking system features a precision laser based vision sensor, automated two-axis machine motion, and an industrial PC controller. The system benefits are elimination of weld repairs caused by joint tracking errors which reduces manufacturing costs and increases production output, simplification of tooling, and free costly manufacturing floor space.

Looney, Alan

1991-01-01

343

Functional near-infrared spectroscopy-based correlates of prefrontal cortical dynamics during a cognitive-motor executive adaptation task  

PubMed Central

This study investigated changes in brain hemodynamics, as measured by functional near infrared spectroscopy, during performance of a cognitive-motor adaptation task. The adaptation task involved the learning of a novel visuomotor transformation (a 60° counterclockwise screen-cursor rotation), which required inhibition of a prepotent visuomotor response. A control group experienced a familiar transformation and thus, did not face any executive challenge. Analysis of the experimental group hemodynamic responses revealed that the performance enhancement was associated with a monotonic reduction in the oxygenation level in the prefrontal cortex. This finding confirms and extends functional magnetic resonance imaging and electroencephalography studies of visuomotor adaptation and learning. The changes in prefrontal brain activation suggest an initial recruitment of frontal executive functioning to inhibit prepotent visuomotor mappings followed by a progressive de-recruitment of the same prefrontal regions. The prefrontal hemodynamic changes observed in the experimental group translated into enhanced motor performance revealed by a reduction in movement time, movement extent, root mean square error and the directional error. These kinematic adaptations are consistent with the acquisition of an internal model of the novel visuomotor transformation. No comparable change was observed in the control group for either the hemodynamics or for the kinematics. This study (1) extends our understanding of the frontal executive processes from the cognitive to the cognitive-motor domain and (2) suggests that optical brain imaging can be employed to provide hemodynamic based-biomarkers to assess and monitor the level of adaptive cognitive-motor performance. PMID:23847489

Gentili, Rodolphe J.; Shewokis, Patricia A.; Ayaz, Hasan; Contreras-Vidal, Jose L.

2013-01-01

344

Near-Infrared Spectroscopy during the Verbal Fluency Task before and after Treatment with Image Exposure and SSRI Therapy in Patients with Obsessive-Compulsive Disorder  

PubMed Central

Drug therapy with selective serotonin reuptake inhibitors (SSRIs) has been used as a treatment for obsessive-compulsive disorder (OCD). In the present case report, exposure therapy was used in addition to escitalopram (20?mg) to treat a 28-year-old female patient with OCD for 6 months. Her obsessive-compulsive symptoms comprised thoughts of words such as rape, crematorium, neck hanging, unhappy, death, die, and kill and images such as a shelf of gods, a shrine, a Buddhist altar, the sun, the sky, and the faces of her parents, siblings, and relatives. As exposure therapy, she was asked to view the images associated with these symptoms three times a day along with drug therapy. With the combination of drug and exposure therapies, her obsessive-compulsive symptoms improved within 6 months, with no interference in her daily life. Multichannel near-infrared spectroscopy (NIRS) showed improvement of brain function in the temporal and frontal lobes after treatment. These results suggest that NIRS can be used as an indicator of brain function improvement in patients with OCD. PMID:25317351

Nakanishi, Mari; Tanaka, Yoshihiro; Inoue, Ayako; Kawashima, Chiwa; Okamoto, Kana; Kobayashi, Shunsuke; Ishitobi, Yoshinobu; Ninomiya, Taiga

2014-01-01

345

Near-Infrared Spectroscopy during the Verbal Fluency Task before and after Treatment with Image Exposure and SSRI Therapy in Patients with Obsessive-Compulsive Disorder.  

PubMed

Drug therapy with selective serotonin reuptake inhibitors (SSRIs) has been used as a treatment for obsessive-compulsive disorder (OCD). In the present case report, exposure therapy was used in addition to escitalopram (20?mg) to treat a 28-year-old female patient with OCD for 6 months. Her obsessive-compulsive symptoms comprised thoughts of words such as rape, crematorium, neck hanging, unhappy, death, die, and kill and images such as a shelf of gods, a shrine, a Buddhist altar, the sun, the sky, and the faces of her parents, siblings, and relatives. As exposure therapy, she was asked to view the images associated with these symptoms three times a day along with drug therapy. With the combination of drug and exposure therapies, her obsessive-compulsive symptoms improved within 6 months, with no interference in her daily life. Multichannel near-infrared spectroscopy (NIRS) showed improvement of brain function in the temporal and frontal lobes after treatment. These results suggest that NIRS can be used as an indicator of brain function improvement in patients with OCD. PMID:25317351

Nakanishi, Mari; Oshita, Harumi; Tanaka, Yoshihiro; Inoue, Ayako; Kawashima, Chiwa; Okamoto, Kana; Kobayashi, Shunsuke; Ishitobi, Yoshinobu; Ninomiya, Taiga; Akiyoshi, Jotaro

2014-01-01

346

From First Life to Second Life: Evaluating Task-Based Language Learning in a New Environment  

ERIC Educational Resources Information Center

With its growing number of users, Second Life as one of the avatar-based 3D virtual worlds has received attention from educators and researchers in various fields to explore its pedagogical benefits. Given the increasing implementation of technologies broadly in much instruction, this study investigated how ESL students negotiated meanings in…

Jee, Min Jung

2014-01-01

347

Engineering Challenges of Deploying Crowd-based Data Collection Tasks to End-User Controlled Smartphones  

E-print Network

Smartphones Hamilton Turner Virginia Tech Blacksburg, VA, USA hamiltont@vt.edu Jules White Virginia Tech The emerging hardware resources available in smartphones has increased the potential for effective crowdsourced crowdsourced data collection. However, given the recent emergence of smartphone-based data collection systems

Gray, Jeffrey G.

348

Task-Based Navigation of a Taxonomy Interface to a Digital Repository  

ERIC Educational Resources Information Center

Introduction: This is a study of hierarchical navigation; how users browse a taxonomy-based interface to an organizational repository to locate information resources. The study is part of a project to develop a taxonomy for an library and information science department to organize resources and support user browsing in a digital repository.…

Khoo, Christopher S. G.; Wang, Zhonghong; Chaudhry, Abdus Sattar

2012-01-01

349

The Relationship between Shared Mental Models and Task Performance in an Online Team- Based Learning Environment  

ERIC Educational Resources Information Center

In an effort to better understand learning teams, this study examines the effects of shared mental models on team and individual performance. The results indicate that each team's shared mental model changed significantly over the time that subjects participated in team-based learning activities. The results also showed that the shared mental…

Johnson, Tristan E.; Lee, Youngmin

2008-01-01

350

BENCHMARKING USER PERFORMANCE BY USING VIRTUAL REALITY FOR TASK-BASED TRAINING  

Microsoft Academic Search

Conveyor belts have a high accident and fatality rate associated with them because of the dangerous environment their constantly moving parts create. Because of this high fatality rate, different methods are being considered to improve current safety training methods. By looking at the principles of cognitive learning and what makes a computer-based training program successful, a safety training program using

Jason Lucas; Walid Thabet

351

The Effects of Task, Database, and Guidance on Interaction in a Goal-Based Scenario.  

ERIC Educational Resources Information Center

This paper describes the "Sickle Cell Counselor" (SCC), a goal based scenario on permanent display at the Museum of Science and Industry in Chicago. SCC is an exploratory hypermedia simulation program which provides users with a basic understanding of Sickle Cell Anemia. The user of the program plays the role of a genetic counselor, and, while…

Bell, Benjamin

352

Language identification techniques based on full recognition in an air traffic control task  

Microsoft Academic Search

Automatic language identification has become an important issue in recent years in speech recognition systems. In this paper, we present the work done in language identification for an air traffic control speech recognizer for continuous speech. The system is able to distinguish between Spanish and English. We present several language identification techniques based on full recognition that improve the baseline

Ricardo de Córdoba; Javier Ferreiros; Valentín Sama; Javier Macías Guarasa; Luis Fernando D'Haro; Fernando Fernandez

2004-01-01

353

Confronting Prospective Teachers' Ideas of Evolution and Scientific Inquiry Using Technology and Inquiry-Based Tasks  

ERIC Educational Resources Information Center

This study addresses the need for research in three areas: (1) teachers' understandings of scientific inquiry; (2) conceptual understandings of evolutionary processes; and (3) technology-enhanced instruction using an inquiry approach. The purpose of this study was to determine in what ways "The Galapagos Finches" software-based materials created a…

Crawford, Barbara A.; Zembal-Saul, Carla; Munford, Danusa; Friedrichsen, Patricia

2005-01-01

354

Differentiating between novice and expert surgeons based on errors derived from task analysis  

Microsoft Academic Search

Motivation -- To capture the salient aspects of decision making during the Laparoscopic Cholecystectomy procedure to differentiate between novice and expert surgeons. The output of this study is being used in the design of a computer based training system for surgical decision making using serious game technology. Research approach -- A series of observations of a range of surgeons performing

David Murphy; Gavin Doherty; Saturnino Luz

2008-01-01

355

Investigating the Use of ICT-Based Concept Mapping Techniques on Creativity in Literacy Tasks  

ERIC Educational Resources Information Center

The key research question in this small-scale study focuses on the effects that an ICT (information and communications technologies)-based concept mapping intervention has on creativity and writing achievement in 10-11-year-old primary age pupils. The data shows that pupils using a concept mapping intervention significantly improve their NFER…

Riley, Nigel R.; Ahlberg, Mauri

2004-01-01

356

Occupational exposure to water based paint and symptoms from the skin and eyes.  

PubMed Central

Water based paints contain organic solvents and many additives, such as biocides, surfactants, pigments, binders, amines, and monomers. The chemical complexity may introduce new potential health hazards to house painters, in particular irritative and allergic disorders. This study was performed to compare how house painters experience work with water based paints or solvent based paints, and to evaluate whether exposure to water based paints increases mucous membrane and dermal symptoms among house painters. 255 male house painters aged 20 to 65 were invited to participate in the study. Controls were two industrial populations, in total 302 men, without exposure to water based paints. Self administered questionnaires were used to assess the painter's experiences of working with different types of paints and the occurrence of symptoms in the exposed and unexposed groups. Hygiene measurements were performed during normal working days when only water based paints and no solvent based paints were used. The painters were exposed to low concentrations of dust, metals, ammonia, formaldehyde, and volatile organic compounds. The work environment was considered better when working with water based paints than with solvent based paints. There were more complaints of frequent urination when working with water based paint. Taste or olfactory disturbances were less common. General as well as work related eye and skin irritation was more common among the exposed workers. For other symptoms no significant differences were found. The study indicates that the introduction of water based paints has improved the work environment for house painters. Water based paints cause less discomfort and airway irritation than the earlier solvent based paints. Adverse general health effects seem low. Some of the painters may have dermal symptoms caused by the components in water based paints. PMID:8130846

Wieslander, G; Norback, D; Edling, C

1994-01-01

357

A size-based probabilistic assessment of PCB exposure from Lake Michigan fish consumption  

SciTech Connect

The state of Wisconsin has recently issued a fish consumption advisory that includes suggested consumption rates for Lake Michigan fish, based on fish size and PCB concentration. To evaluate the size-based exposure risk from Lake Michigan fish consumption, the authors estimated PCB exposure probabilities for five Lake Michigan fish species using two Bayesian models. The models confirm that very few individuals of any of the five species are likely to have PCB concentrations low enough to fall into the category in which consumption is unrestricted. Among smaller fish (<50 cm), brown trout have the highest PCB levels, while lake trout are the most contaminated among larger fish (>60 cm). Eating meals from multiple individuals of some species results in a high probability that at least one of the meals will exceed 1.9 mg/kg, the upper PCB concentration recommended for consumption in the advisory.

Stow, C.A. [Duke Univ., Durham, NC (United States). Nicholas School of the Environment] [Duke Univ., Durham, NC (United States). Nicholas School of the Environment; Qian, S.S. [Portland State Univ., OR (United States)] [Portland State Univ., OR (United States)

1998-08-01

358

Touchscreen-Based Cognitive Tasks Reveal Age-Related Impairment in a Primate Aging Model, the Grey Mouse Lemur (Microcebus murinus)  

PubMed Central

Mouse lemurs are suggested to represent promising novel non-human primate models for aging research. However, standardized and cross-taxa cognitive testing methods are still lacking. Touchscreen-based testing procedures have proven high stimulus control and reliability in humans and rodents. The aim of this study was to adapt these procedures to mouse lemurs, thereby exploring the effect of age. We measured appetitive learning and cognitive flexibility of two age groups by applying pairwise visual discrimination (PD) and reversal learning (PDR) tasks. On average, mouse lemurs needed 24 days of training before starting with the PD task. Individual performances in PD and PDR tasks correlate significantly, suggesting that individual learning performance is unrelated to the respective task. Compared to the young, aged mouse lemurs showed impairments in both PD and PDR tasks. They needed significantly more trials to reach the task criteria. A much higher inter-individual variation in old than in young adults was revealed. Furthermore, in the PDR task, we found a significantly higher perseverance in aged compared to young adults, indicating an age-related deficit in cognitive flexibility. This study presents the first touchscreen-based data on the cognitive skills and age-related dysfunction in mouse lemurs and provides a unique basis to study mechanisms of inter-individual variation. It furthermore opens exciting perspectives for comparative approaches in aging, personality, and evolutionary research. PMID:25299046

2014-01-01

359

Touchscreen-Based Cognitive Tasks Reveal Age-Related Impairment in a Primate Aging Model, the Grey Mouse Lemur (Microcebus murinus).  

PubMed

Mouse lemurs are suggested to represent promising novel non-human primate models for aging research. However, standardized and cross-taxa cognitive testing methods are still lacking. Touchscreen-based testing procedures have proven high stimulus control and reliability in humans and rodents. The aim of this study was to adapt these procedures to mouse lemurs, thereby exploring the effect of age. We measured appetitive learning and cognitive flexibility of two age groups by applying pairwise visual discrimination (PD) and reversal learning (PDR) tasks. On average, mouse lemurs needed 24 days of training before starting with the PD task. Individual performances in PD and PDR tasks correlate significantly, suggesting that individual learning performance is unrelated to the respective task. Compared to the young, aged mouse lemurs showed impairments in both PD and PDR tasks. They needed significantly more trials to reach the task criteria. A much higher inter-individual variation in old than in young adults was revealed. Furthermore, in the PDR task, we found a significantly higher perseverance in aged compared to young adults, indicating an age-related deficit in cognitive flexibility. This study presents the first touchscreen-based data on the cognitive skills and age-related dysfunction in mouse lemurs and provides a unique basis to study mechanisms of inter-individual variation. It furthermore opens exciting perspectives for comparative approaches in aging, personality, and evolutionary research. PMID:25299046

Joly, Marine; Ammersdörfer, Sandra; Schmidtke, Daniel; Zimmermann, Elke

2014-01-01

360

Classifying real and imaginary finger press tasks on a P300-based brain-computer interface  

Microsoft Academic Search

Brain computer interfaces based on P300 and sensory-motor rhythms are widely studied and recent advances show some interest in the combination of the two. In this paper, typical P300 paradigm is modified by adding animation guide of the finger press as a stimulus and by using different response strategies (silent counting and actual\\/imaginary left or right index finger press following

Jicai Zhang; Weidong Chen; Yanlei Gu; Bian Wu; Yu Qi; Xiaoxiang Zheng

2011-01-01

361

TeamWorker: An Agent-Based Support System for Mobile Task Execution  

Microsoft Academic Search

An organization’s mobile workforce is a vital asset, as it is in the front line liaising with customers, and driving the sale of an organization’s products and\\/or services. Despite this, the IT support provided to mobile workers is often inferior to that available to office-based workers. Mobile workers operate in an unreliable environment, and as such require differing types of

Habin Lee; Patrik Mihailescu; John Shepherdson

362

Changes in Mindfulness and Emotion Regulation in an Exposure-Based Cognitive Therapy for Depression  

Microsoft Academic Search

With the mounting evidence for mindfulness training as a promising strategy for distress reduction across clinical and nonclinical\\u000a populations, it is important to learn more about the kinds of changes associated with this training. In an exposure-based\\u000a cognitive therapy for depression that includes mindfulness training, participants reported significant increases in mindfulness\\u000a over the course of therapy. Hierarchical linear modeling revealed

Sameet Kumar; Greg Feldman; Adele Hayes

2008-01-01

363

Implementation and operation of VAX-based data acquisition system for the large coil task  

SciTech Connect

The VAX-based data acquisition system for the International Fusion Superconducting Magnet Test Facility (IFSMTF) at Oak Ridge National Laboratory (ORNL) is a second generation system that evolved from a PDP-11/60-based system used in the two-coil test and facility shakedown. The VAX 11/780 processor has been interfaced through a CAMAC fiber-optic byte serial highway to five existing LSI-11/23 frontend processors through dataway access port (DAP) modules. The VAX CAMAC interface has permitted the addition of analog input channels for the refrigeration system and analog and digital outputs to drive display devices. Software utilities are provided to operate the data acquisition hardware, maintain data base files, and display data. Graphical display of data is accomplished through the use of VAX IDL (Interactive Data Language), which provides device-independent data presentation. Output from IDL is available for Tektronix displays and has been extended to generate TKF and Versaplot graphics metafiles for hardcopy output to Versatec printer/plotters. In addition, a Sension display system is available for graphical display of real-time data in the form of strip chart and tabular displays. This paper describes the hardware and software design of the system and the operation of the system during the full-array testing sequence.

Baylor, L.R.; Blair, E.T.; Greenwood, D.E.; Munro, J.K.

1985-01-01

364

AAAI Fall Symposium on Advances in Cognitive Systems, Arlington, VA, 4 -6 November 2011. Cognitive Assistants for Evidence-Based Reasoning Tasks  

E-print Network

Assistants for Evidence-Based Reasoning Tasks Mihai Boicu, Dorin Marcu, Gheorghe Tecuci, David Schum Learning Agents Center, George Mason University, Fairfax, VA 22030 Abstract Evidence-based reasoning introduces a computational theory of evidence-based reasoning, the architecture of a learning agent shell

Tecuci, Gheorghe

365

Probabilistic modeling of percutaneous absorption for risk-based exposure assessments and transdermal drug delivery.  

SciTech Connect

Chemical transport through human skin can play a significant role in human exposure to toxic chemicals in the workplace, as well as to chemical/biological warfare agents in the battlefield. The viability of transdermal drug delivery also relies on chemical transport processes through the skin. Models of percutaneous absorption are needed for risk-based exposure assessments and drug-delivery analyses, but previous mechanistic models have been largely deterministic. A probabilistic, transient, three-phase model of percutaneous absorption of chemicals has been developed to assess the relative importance of uncertain parameters and processes that may be important to risk-based assessments. Penetration routes through the skin that were modeled include the following: (1) intercellular diffusion through the multiphase stratum corneum; (2) aqueous-phase diffusion through sweat ducts; and (3) oil-phase diffusion through hair follicles. Uncertainty distributions were developed for the model parameters, and a Monte Carlo analysis was performed to simulate probability distributions of mass fluxes through each of the routes. Sensitivity analyses using stepwise linear regression were also performed to identify model parameters that were most important to the simulated mass fluxes at different times. This probabilistic analysis of percutaneous absorption (PAPA) method has been developed to improve risk-based exposure assessments and transdermal drug-delivery analyses, where parameters and processes can be highly uncertain.

Ho, Clifford Kuofei

2004-06-01

366

Base camp personnel exposure to particulate matter during wildland fire suppression activities.  

PubMed

Wildland fire base camps commonly house thousands of support personnel for weeks at a time. The selection of the location of these base camps is largely a strategic decision that incorporates many factors, one of which is the potential impact of biomass smoke from the nearby fire event. Biomass smoke has many documented adverse health effects due, primarily, to high levels of fine particulate matter (PM(2.5)). Minimizing particulate matter exposure to potentially susceptible individuals working as support personnel in the base camp is vital. In addition to smoke from nearby wildland fires, base camp operations have the potential to generate particulate matter via vehicle emissions, dust, and generator use. We monitored particulate matter at three base camps during the fire season of 2009 in Washington, Oregon, and California. During the sampling events, 1-min time-weighted averages of PM(2.5) and particle counts from three size fractions (0.3-0.5 microns, 0.5-1.0 microns, and 1.0-2.5 microns) were measured. Results showed that all PM size fractions (as well as overall PM(2.5) concentrations) were higher during the overnight hours, a trend that was consistent at all camps. Our results provide evidence of camp-based, site-specific sources of PM(2.5) that could potentially exceed the contributions from the nearby wildfire. These exposures could adversely impact wildland firefighters who sleep in the camp, as well as the camp support personnel, who could include susceptible individuals. A better understanding of the sources and patterns of poor air quality within base camps would help to inform prevention strategies to reduce personnel exposures. PMID:22364357

McNamara, Marcy L; Semmens, Erin O; Gaskill, Steven; Palmer, Charles; Noonan, Curtis W; Ward, Tony J

2012-01-01

367

Task Description Language  

NASA Technical Reports Server (NTRS)

Task Description Language (TDL) is an extension of the C++ programming language that enables programmers to quickly and easily write complex, concurrent computer programs for controlling real-time autonomous systems, including robots and spacecraft. TDL is based on earlier work (circa 1984 through 1989) on the Task Control Architecture (TCA). TDL provides syntactic support for hierarchical task-level control functions, including task decomposition, synchronization, execution monitoring, and exception handling. A Java-language-based compiler transforms TDL programs into pure C++ code that includes calls to a platform-independent task-control-management (TCM) library. TDL has been used to control and coordinate multiple heterogeneous robots in projects sponsored by NASA and the Defense Advanced Research Projects Agency (DARPA). It has also been used in Brazil to control an autonomous airship and in Canada to control a robotic manipulator.

Simmons, Reid; Apfelbaum, David

2005-01-01

368

Incidence of prenatal alcohol exposure in Prince Edward Island: a population-based descriptive study  

PubMed Central

Background Fetal alcohol spectrum disorder (FASD) is a leading preventable cause of neurodevelopmental disability in North America. The stigma associated with alcohol use and abuse during pregnancy makes it difficult to obtain information on prenatal alcohol use through self-reporting. We assessed the incidence of prenatal alcohol exposure in Prince Edward Island to facilitate future public health initiatives addressing FASD. Methods Prenatal alcohol exposure was examined via population-based collection of meconium and analysis of fatty acid ethyl esters (FAEEs). Fatty acid ethyl esters are nonoxidative metabolites of ethanol that are produced in the fetus. Meconium FAEE concentrations of 2.0 nmol/g or greater are indicative of frequent prenatal alcohol exposure during the last 2 trimesters of pregnancy. Samples were collected from 1307 neonates between Nov. 8, 2010, and Nov. 8, 2011, in hospitals in PEI, or from those born to mothers who resided in PEI but gave birth in Halifax, Nova Scotia. Samples were frozen and shipped for analysis. Fatty acid ethyl esters were analyzed by gas chromatography–mass spectrometry and quantified by means of deuterated internal standards. Results Of the 1307 samples collected, 1271 samples were successfully analyzed. Positive results for FAEEs were obtained in 3.1% (n = 39) of samples collected within the first 24 hours after birth. Interpretation Not all neonates exposed to heavy prenatal alcohol in utero will exhibit FASD; based on current estimates of predictive value for disease by exposure, our findings suggest that 1.3% of neonates born in PEI during this 1-year period will have FASD. In its application to an entire provincial birth cohort, this study successfully implemented a public health–centred approach for evaluating population-based risk of FASD, with implications for practice across Canada. PMID:25077128

Bryanton, Janet; Boswall, Diane; McCarthy, Mary Jean; Fraser, Bonnie; Walsh, Donna; Freeman, Bridget; Koren, Gideon; Bigsby, Kathy

2014-01-01

369

Time Averaged Transmitter Power and Exposure to Electromagnetic Fields from Mobile Phone Base Stations  

PubMed Central

Models for exposure assessment of high frequency electromagnetic fields from mobile phone base stations need the technical data of the base stations as input. One of these parameters, the Equivalent Radiated Power (ERP), is a time-varying quantity, depending on communication traffic. In order to determine temporal averages of the exposure, corresponding averages of the ERP have to be available. These can be determined as duty factors, the ratios of the time-averaged power to the maximum output power according to the transmitter setting. We determine duty factors for UMTS from the data of 37 base stations in the Swisscom network. The UMTS base stations sample contains sites from different regions of Switzerland and also different site types (rural/suburban/urban/hotspot). Averaged over all regions and site types, a UMTS duty factor F ? 0.32 ± 0.08 for the 24 h-average is obtained, i.e., the average output power corresponds to about a third of the maximum power. We also give duty factors for GSM based on simple approximations and a lower limit for LTE estimated from the base load on the signalling channels. PMID:25105551

Burgi, Alfred; Scanferla, Damiano; Lehmann, Hugo

2014-01-01

370

Time averaged transmitter power and exposure to electromagnetic fields from mobile phone base stations.  

PubMed

Models for exposure assessment of high frequency electromagnetic fields from mobile phone base stations need the technical data of the base stations as input. One of these parameters, the Equivalent Radiated Power (ERP), is a time-varying quantity, depending on communication traffic. In order to determine temporal averages of the exposure, corresponding averages of the ERP have to be available. These can be determined as duty factors, the ratios of the time-averaged power to the maximum output power according to the transmitter setting. We determine duty factors for UMTS from the data of 37 base stations in the Swisscom network. The UMTS base stations sample contains sites from different regions of Switzerland and also different site types (rural/suburban/urban/hotspot). Averaged over all regions and site types, a UMTS duty factor for the 24 h-average is obtained, i.e., the average output power corresponds to about a third of the maximum power. We also give duty factors for GSM based on simple approximations and a lower limit for LTE estimated from the base load on the signalling channels. PMID:25105551

Bürgi, Alfred; Scanferla, Damiano; Lehmann, Hugo

2014-08-01

371

Risk based management of contaminated sediments: consideration of spatial and temporal patterns in exposure modeling.  

PubMed

This paper addresses interactions among foraging behavior, habitat preferences, site characteristics, and spatial distribution of contaminants in developing PCB exposure estimates for winter flounder at a hypothetical open water dredged material disposal site in the coastal waters of New York and New Jersey (NY-NJ). The implications of these interactions for human health risk estimates for local recreational anglers who fish for and eat flounder are described. The models implemented in this study include a spatial submodel to account for spatial and temporal characteristics of fish exposures and a probabilistic adaptation of the Gobas bioaccumulation model that accounts for temporal variation in concentrations of hydrophobic contaminants in sediment and water. We estimated the geographic distribution of a winter flounder subpopulation offshore of NY-NJ based on species biology and its vulnerability to local recreational fishing, the foraging area of individual fish, and their migration patterns. We incorporated these parameters and an estimate of differential attraction to a management site into a spatially explicit model to assess the range of exposures within the population. The output of this modeling effort, flounder PCB tissue concentrations, provided exposure point concentrations for an estimate of human health risk through ingestion of locally caught flounder. The risks obtained for the spatially nonexplicit case are as much as 1 order of magnitude higher than those obtained with explicit consideration of spatial and temporal characteristics of winter flounder foraging and seasonal migration. This practice of "defaulting" to extremely conservative estimates for exposure parameters in the face of uncertainty ill serves the decision-making process for management of contaminated sediments in general and specifically for disposal of dredged materials. Consideration of realistic spatial and temporal scales in food chain models can help support sediment management decisions by providing a quantitative expression of the confidence in risk estimates. PMID:11827058

Linkov, Igor; Burmistrov, Dmitriy; Cura, Jerome; Bridges, Todd S

2002-01-15

372

The double task of preventing malnutrition and overweight: a quasi-experimental community-based trial  

PubMed Central

Background The Maternal-Child Pastoral is a volunteer-based community organization of the Dominican Republic that works with families to improve child survival and development. A program that promotes key practices of maternal and child care through meetings with pregnant women and home visits to promote child growth and development was designed and implemented. This study aims to evaluate the impact of the program on nutritional status indicators of children in the first two years of age. Methods A quasi-experimental design was used, with groups paired according to a socioeconomic index, comparing eight geographical areas of intervention with eight control areas. The intervention was carried out by lay health volunteers. Mothers in the intervention areas received home visits each month and participated in a group activity held biweekly during pregnancy and monthly after birth. The primary outcomes were length and body mass index for age. Statistical analyses were based on linear and logistic regression models. Results 196 children in the intervention group and 263 in the control group were evaluated. The intervention did not show statistically significant effects on length, but point estimates found were in the desired direction: mean difference 0.21 (95%CI ?0.02; 0.44) for length-for-age Z-score and OR 0.50 (95%CI 0.22; 1.10) for stunting. Significant reductions of BMI-for-age Z-score (?0.31, 95%CI ?0.49; -0.12) and of BMI-for-age > 85th percentile (0.43, 95%CI 0.23; 0.77) were observed. The intervention showed positive effects in some indicators of intermediary factors such as growth monitoring, health promotion activities, micronutrient supplementation, exclusive breastfeeding and complementary feeding. Conclusions Despite finding effect measures pointing to effects in the desired direction related to malnutrition, we could only detect a reduction in the risk of overweight attributable to the intervention. The findings related to obesity prevention may be of interest in the context of the nutritional transition. Given the size of this study, the results are encouraging and we believe a larger study is warranted. PMID:23496939

2013-01-01

373

ECONOMIC EVALUATION OF CO2 SEQUESTRATION TECHNOLOGIES TASK 4, BIOMASS GASIFICATION-BASED PROCESSING  

SciTech Connect

Biomass derived energy currently accounts for about 3 quads of total primary energy use in the United States. Of this amount, about 0.8 quads are used for power generation. Several biomass energy production technologies exist today which contribute to this energy mix. Biomass combustion technologies have been the dominant source of biomass energy production, both historically and during the past two decades of expansion of modern biomass energy in the U. S. and Europe. As a research and development activity, biomass gasification has usually been the major emphasis as a method of more efficiently utilizing the energy potential of biomass, particularly wood. Numerous biomass gasification technologies exist today in various stages of development. Some are simple systems, while others employ a high degree of integration for maximum energy utilization. The purpose of this study is to conduct a technical and economic comparison of up to three biomass gasification technologies, including the carbon dioxide emissions reduction potential of each. To accomplish this, a literature search was first conducted to determine which technologies were most promising based on a specific set of criteria. During this reporting period, the technical and economic performances of the selected processes were evaluated using computer models and available literature. The results of these evaluations are summarized in this report.

Martha L. Rollins; Les Reardon; David Nichols; Patrick Lee; Millicent Moore; Mike Crim; Robert Luttrell; Evan Hughes

2002-04-01

374

ECONOMIC EVALUATION OF CO2 SEQUESTRATION TECHNOLOGIES TASK 4, BIOMASS GASIFICATION-BASED PROCESSING  

SciTech Connect

Biomass derived energy currently accounts for about 3 quads of total primary energy use in the United States. Of this amount, about 0.8 quads are used for power generation. Several biomass energy production technologies exist today which contribute to this energy mix. Biomass combustion technologies have been the dominant source of biomass energy production, both historically and during the past two decades of expansion of modern biomass energy in the U. S. and Europe. As a research and development activity, biomass gasification has usually been the major emphasis as a method of more efficiently utilizing the energy potential of biomass, particularly wood. Numerous biomass gasification technologies exist today in various stages of development. Some are simple systems, while others employ a high degree of integration for maximum energy utilization. The purpose of this study is to conduct a technical and economic comparison of up to three biomass gasification technologies, including the carbon dioxide emissions reduction potential of each. To accomplish this, a literature search was first conducted to determine which technologies were most promising based on a specific set of criteria. The technical and economic performances of the selected processes were evaluated using computer models and available literature. Using these results, the carbon sequestration potential of the three technologies was then evaluated. The results of these evaluations are given in this final report.

Martha L. Rollins; Les Reardon; David Nichols; Patrick Lee; Millicent Moore; Mike Crim; Robert Luttrell; Evan Hughes

2002-06-01

375

Task-Based Core-Periphery Organization of Human Brain Dynamics  

PubMed Central

As a person learns a new skill, distinct synapses, brain regions, and circuits are engaged and change over time. In this paper, we develop methods to examine patterns of correlated activity across a large set of brain regions. Our goal is to identify properties that enable robust learning of a motor skill. We measure brain activity during motor sequencing and characterize network properties based on coherent activity between brain regions. Using recently developed algorithms to detect time-evolving communities, we find that the complex reconfiguration patterns of the brain's putative functional modules that control learning can be described parsimoniously by the combined presence of a relatively stiff temporal core that is composed primarily of sensorimotor and visual regions whose connectivity changes little in time and a flexible temporal periphery that is composed primarily of multimodal association regions whose connectivity changes frequently. The separation between temporal core and periphery changes over the course of training and, importantly, is a good predictor of individual differences in learning success. The core of dynamically stiff regions exhibits dense connectivity, which is consistent with notions of core-periphery organization established previously in social networks. Our results demonstrate that core-periphery organization provides an insightful way to understand how putative functional modules are linked. This, in turn, enables the prediction of fundamental human capacities, including the production of complex goal-directed behavior. PMID:24086116

Bassett, Danielle S.; Wymbs, Nicholas F.; Rombach, M. Puck; Porter, Mason A.; Mucha, Peter J.; Grafton, Scott T.

2013-01-01

376

Research on stable, high-efficiency, large-area, amorphous-silicon-based submodules, task B  

NASA Astrophysics Data System (ADS)

This research concerns the improvement of the efficiency and stability of large-area amorphous silicon photovoltaic submodules, based on both single- and tandem-junction device structures. For the improvement of cell efficiency, carbon-graded a-Si(x)C(1-x):H p-layers, ITO/Ag back reflectors, alternate SnO2 substrates, and TiO(x) recombination layers at the n/p interface of tandem cells are described. Significant contributions to the study of transport and defect states in a-Si:H were made using the steady-state photocarrier grating technique, charge collection in thick p-i-n structures, thermally stimulated currents, and current DLTS. An extensive study of the deposition of SiO2 barrier layers on soda lime glass to improve SnO2:F conductivity is reported. Submodule research includes laser isolation, active scribe tracking, post-fabrication defect removal, and a new interconnect scheme employing two levels of metallization. Power output and aperture area efficiency for single junction submodules were 5.9W (7.0 percent) for 1 x 1 sq. ft. and 17.7W (6.9 percent) for 1 x 3 sq. ft. Outdoor stability tests on glass-glass encapsulated tandem submodules are also described.

Delahoy, A. E.; Kampas, F. J.

1989-06-01

377

Confronting prospective teachers' ideas of evolution and scientific inquiry using technology and inquiry-based tasks  

NASA Astrophysics Data System (ADS)

This study addresses the need for research in three areas: (1) teachers' understandings of scientific inquiry; (2) conceptual understandings of evolutionary processes; and (3) technology-enhanced instruction using an inquiry approach. The purpose of this study was to determine in what ways The Galapagos Finches software-based materials created a context for learning and teaching about the nature of scientific knowledge and evolutionary concepts. The research used a design experiment in which researchers significantly modified a secondary science methods course. The multiple data sources included: audiotaped conversations of two focus pairs of participants as they interacted with the software; written pre- and posttests on concepts of natural selection of the 21 prospective teachers; written pre- and posttests on views of the nature of science; three e-mail journal questions; and videotaped class discussions. Findings indicate that prospective teachers initially demonstrated alternative understandings of evolutionary concepts; there were uninformed understandings of the nature of scientific inquiry; there was little correlation between understandings and disciplines; and even the prospective teachers with research experience failed to understand the diverse methods used by scientists. Following the module there was evidence of enhanced understandings through metacognition, and the potential for interactive software to provide promising context for enhancing content understandings.

Crawford, Barbara A.; Zembal-Saul, Carla; Munford, Danusa; Friedrichsen, Patricia

2005-08-01

378

Benzene and total hydrocarbons exposures in the downstream petroleum industries.  

PubMed

A review of studies, including both articles published in peer-reviewed journals and reports that were not peer reviewed, regarding occupational exposure to benzene and total hydrocarbons in the downstream petroleum industry operations was performed. The objective was to provide a broad estimate of exposures by compiling exposure data according to the following categories: refinery, pipeline, marine, rail, bulk terminals and trucks, service stations, underground storage tanks, tank cleaning, and site remediations. The data in each category was divided into personal occupational long-term and short-term samples. The summarized data offers valuable assistance to hygienists by providing them with an estimate and range of exposures. The traditional 8-hour time-weighted average (TWA) exposure and the 40-hour workweek do not generally coincide with exposure periods applicable to workers in marine, pipeline, railcar, and trucking operations. They are more comparable with short-term exposure or task-based exposure assessments. The marine sector has a large number of high exposures. Although relatively few workers are exposed, their exposures to benzene and total hydrocarbons are sometimes an order of magnitude higher than the respective exposure limits. It is recommended that in the future, it would be preferable to do more task-based exposure assessments and fewer traditional TWA long-term exposure assessments within the various sectors of the downstream petroleum industry. PMID:11331990

Verma, D K; Johnson, D M; Shaw, M L; des Tombe, K

2001-01-01

379

A new human perception-based over-exposure detection method for color images.  

PubMed

To correct an over-exposure within an image, the over-exposed region (OER) must first be detected. Detecting the OER accurately has a significant effect on the performance of the over-exposure correction. However, the results of conventional OER detection methods, which generally use the brightness and color information of each pixel, often deviate from the actual OER perceived by the human eye. To overcome this problem, in this paper, we propose a novel method for detecting the perceived OER more accurately. Based on the observation that recognizing the OER in an image is dependent on the saturation sensitivity of the human visual system (HVS), we detect the OER by thresholding the saturation value of each pixel. Here, a function of the proposed method, which is designed based on the results of a subjective evaluation on the saturation sensitivity of the HVS, adaptively determines the saturation threshold value using the color and the perceived brightness of each pixel. Experimental results demonstrate that the proposed method accurately detects the perceived OER, and furthermore, the over-exposure correction can be improved by adopting the proposed OER detection method. PMID:25225876

Yoon, Yeo-Jin; Byun, Keun-Yung; Lee, Dae-Hong; Jung, Seung-Won; Ko, Sung-Jea

2014-01-01

380

Ghost detection and removal based on super-pixel grouping in exposure fusion  

NASA Astrophysics Data System (ADS)

A novel multi-exposure images fusion method for dynamic scenes is proposed. The commonly used techniques for high dynamic range (HDR) imaging are based on the combination of multiple differently exposed images of the same scene. The drawback of these methods is that ghosting artifacts will be introduced into the final HDR image if the scene is not static. In this paper, a super-pixel grouping based method is proposed to detect the ghost in the image sequences. We introduce the zero mean normalized cross correlation (ZNCC) as a measure of similarity between a given exposure image and the reference. The calculation of ZNCC is implemented in super-pixel level, and the super-pixels which have low correlation with the reference are excluded by adjusting the weight maps for fusion. Without any prior information on camera response function or exposure settings, the proposed method generates low dynamic range (LDR) images which can be shown on conventional display devices directly with details preserving and ghost effects reduced. Experimental results show that the proposed method generates high quality images which have less ghost artifacts and provide a better visual quality than previous approaches.

Jiang, Shenyu; Xu, Zhihai; Li, Qi; Chen, Yueting; Feng, Huajun

2014-09-01

381

A New Human Perception-Based Over-Exposure Detection Method for Color Images  

PubMed Central

To correct an over-exposure within an image, the over-exposed region (OER) must first be detected. Detecting the OER accurately has a significant effect on the performance of the over-exposure correction. However, the results of conventional OER detection methods, which generally use the brightness and color information of each pixel, often deviate from the actual OER perceived by the human eye. To overcome this problem, in this paper, we propose a novel method for detecting the perceived OER more accurately. Based on the observation that recognizing the OER in an image is dependent on the saturation sensitivity of the human visual system (HVS), we detect the OER by thresholding the saturation value of each pixel. Here, a function of the proposed method, which is designed based on the results of a subjective evaluation on the saturation sensitivity of the HVS, adaptively determines the saturation threshold value using the color and the perceived brightness of each pixel. Experimental results demonstrate that the proposed method accurately detects the perceived OER, and furthermore, the over-exposure correction can be improved by adopting the proposed OER detection method. PMID:25225876

Yoon, Yeo-Jin; Byun, Keun-Yung; Lee, Dae-Hong; Jung, Seung-Won; Ko, Sung-Jea

2014-01-01

382

Community-Based Participatory Research and Policy Advocacy to Reduce Diesel Exposure in West Oakland, California  

PubMed Central

We conducted a multimethod case study analysis of a community-based participatory research partnership in West Oakland, California, and its efforts to study and address the neighborhood's disproportionate exposure to diesel air pollution. We employed 10 interviews with partners and policymakers, participant observation, and a review of documents. Results of the partnership's truck count and truck idling studies suggested substantial exposure to diesel pollution and were used by the partners and their allies to make the case for a truck route ordinance. Despite weak enforcement, the partnership's increased political visibility helped change the policy environment, with the community partner now heavily engaged in environmental decision-making on the local and regional levels. Finally, we discussed implications for research, policy, and practice. PMID:21551381

Gonzalez, Priscilla A.; Garcia, Analilia P.; Gordon, Margaret; Garzon, Catalina; Palaniappan, Meena; Prakash, Swati; Beveridge, Brian

2011-01-01

383

Comparison of flying qualities derived from in-flight and ground-based simulators for a jet-transport airplane for the approach and landing pilot tasks  

NASA Technical Reports Server (NTRS)

The primary objective was to provide information to the flight controls/flying qualities engineer that will assist him in determining the incremental flying qualities and/or pilot-performance differences that may be expected between results obtained via ground-based simulation (and, in particular, the six-degree-of-freedom Langley Visual/Motion Simulator (VMS)) and flight tests. Pilot opinion and performance parameters derived from a ground-based simulator and an in-flight simulator are compared for a jet-transport airplane having 32 different longitudinal dynamic response characteristics. The primary pilot tasks were the approach and landing tasks with emphasis on the landing-flare task. The results indicate that, in general, flying qualities results obtained from the ground-based simulator may be considered conservative-especially when the pilot task requires tight pilot control as during the landing flare. The one exception to this, according to the present study, was that the pilots were more tolerant of large time delays in the airplane response on the ground-based simulator. The results also indicated that the ground-based simulator (particularly the Langley VMS) is not adequate for assessing pilot/vehicle performance capabilities (i.e., the sink rate performance for the landing-flare task when the pilot has little depth/height perception from the outside scene presentation).

Grantham, William D.

1989-01-01

384

Preoperative Mapping of the Sensorimotor Cortex: Comparative Assessment of Task-Based and Resting-State fMRI  

PubMed Central

Resting state fMRI (rs-fMRI) has recently been considered as a possible complement or alternative to task-based fMRI (tb-fMRI) for presurgical mapping. However, evidence of its usefulness remains scant, because existing studies have investigated relatively small samples and focused primarily on qualitative evaluation. The aim of this study is to investigate the clinical usefulness of rs-fMRI in the context of presurgical mapping of motor functions, and in particular to determine the degree of correspondence with tb-fMRI which, while not a gold-standard, is commonly used in preoperative setting. A group of 13 patients with lesions close to the sensorimotor cortex underwent rs-fMRI and tb-fMRI to localize the hand, foot and mouth motor areas. We assessed quantitatively the degree of correspondence between multiple rs-fMRI analyses (independent-component and seed-based analyses) and tb-fMRI, with reference to sensitivity and specificity of rs-fMRI with respect to tb-fMRI, and centre-of-mass distances. Agreement with electro-cortical stimulation (ECS) was also investigated, and a traditional map thresholding approach based on agreement between two experienced operators was compared to an automatic threshold determination method. Rs-fMRI can localize the sensorimotor cortex successfully, providing anatomical specificity for hand, foot and mouth motor subregions, in particular with seed-based analyses. Agreement with tb-fMRI was only partial and rs-fMRI tended to provide larger patterns of correlated activity. With respect to the ECS data available, rs-fMRI and tb-fMRI performed comparably, even though the shortest distance to stimulation points was observed for the latter. Notably, the results of both were on the whole robust to thresholding procedure. Localization performed by rs-fMRI is not equivalent to tb-fMRI, hence rs-fMRI cannot be considered as an outright replacement for tb-fMRI. Nevertheless, since there is significant agreement between the two techniques, rs-fMRI can be considered with caution as a potential alternative to tb-fMRI when patients are unable to perform the task. PMID:24914775

Rosazza, Cristina; Aquino, Domenico; D'Incerti, Ludovico; Cordella, Roberto; Andronache, Adrian; Zaca, Domenico; Bruzzone, Maria Grazia; Tringali, Giovanni; Minati, Ludovico

2014-01-01

385

Task Interpretation and Task Effectiveness: A Vygotskian Analysis of a French L2 Classroom Task.  

ERIC Educational Resources Information Center

This paper focuses on second language (L2) learning through task-based interaction as well as the compatibility of the theories of task-based learning and Vygotsky's sociocultural theory. Language tasks encourage L2 learning by using language as a tool to accomplish a goal. This study analyzes the interaction of first-semester French students…

Myers, Lindsy L.

2000-01-01

386

Cigarette Filter-based Assays as Proxies for Toxicant Exposure and Smoking Behavior A Literature Review  

PubMed Central

Background Cigarettes are being marketed with filters that differ in composition and design. The filters have different toxicant trapping efficiency and smoking stains reflect variations in smoking behavior. Presented herein are the results of a structured literature review that was performed to identify cigarette filter-based assays that may serve as proxies for mouth-level exposure and assessing smoking methods. Methods A search of the published scientific literature and internal tobacco company documents from 1954 to 2009 was performed. Results The literature search identified diverse schemes for assessing cigarette filters, including visual inspection and digital imaging of smoked-stained spent filters, and quantitative determinations for total particulate matter (TPM), nicotine, and solanesol. The results also showed that: (a) there is sufficient data to link filter-based chemical measures to standardized smoking machine-measured yields of tar and nicotine; (b) TPM eluted from filters or in chemical digest of filters can be used to estimate the efficiency of the filter for trapping smoke solids; (c) visual and digital inspection of spent filters are useful as indicators of variations in smoking behaviors; and (d) there is a correlation between solanesol and nicotine measured in filters and exposure biomarkers in smokers. Conclusions The cigarette filter may prove useful in estimating smoking behaviors such as filter vent blocking and puffing intensity, and may have utility as proxy measures of mouth-level smoke exposure in clinical trials. Additional investigations are needed to compare the different proposed assay schemes and the assay results with measurements of human biomarker assays of smoke exposure. PMID:19959679

Pauly, John L.; O'Connor, Richard J.; Paszkiewicz, Geraldine M.; Cummings, K. Michael; Djordjevic, Mirjana V.; Shields, Peter G.

2009-01-01

387

High-quality Video Denoising for Motion-based Exposure Control Travis Portz Li Zhang Hongrui Jiang  

E-print Network

denoising in the context of motion-based exposure control. Unlike previous denois- ing works which either curve with varying speed. Bottom: If a con- stant short exposure is applied to each frame to minimize the shutter button is half-pressed) and adjust the shutter and ISO setting so that blur is min- imized

Jiang, Hongrui

388

Ethylene glycol exposure: an evidence-based consensus guideline for out-of-hospital management.  

PubMed

In 2002, poison centers in the US reported 5816 human exposures to ethylene glycol. A guideline that effectively determines the threshold dose for emergency department referral and need for pre-hospital decontamination could potentially avoid unnecessary emergency department visits, reduce health care costs, optimize patient outcome, and reduce life disruption for patients and caregivers. An evidence-based expert consensus process was used to create this guideline. Relevant articles were abstracted by a trained physician researcher. The first draft of the guideline was created by the primary author. The entire panel discussed and refined the guideline before distribution to secondary reviewers for comment. The panel then made changes based on the secondary review comments. The objective of this guideline is to assist poison center personnel in the out-of-hospital triage and initial management of patients with a suspected exposure to ethylene glycol by (1) describing the process by which the exposure might be evaluated, (2) identifying the key decision elements in managing the case, (3) providing clear and practical recommendations that reflect the current state of knowledge, and (4) identifying needs for research. This guideline is based on an assessment of current scientific and clinical information. The panel recognizes that specific patient care decisions may be at variance with this guideline and are the prerogative of the patient and health professionals providing care, considering all of the circumstances involved. Recommendations are in chronological order of likely clinical use. The grade of recommendation is in parentheses. (1) A patient with exposure due to suspected self-harm, misuse, or potentially malicious administration should be referred to an emergency department immediately regardless of the dose reported (Grade D). (2) Patients with inhalation exposures will not develop systemic toxicity and can be managed out-of-hospital if asymptomatic (Grade B). Patients with clinically significant mucous membrane irritation should be referred for evaluation (Grade D). (3) Decontamination of dermal exposures should include routine cleansing with mild soap and water. Removal of contact lenses and immediate irrigation with room temperature tap water is recommended for ocular exposures. All patients with symptoms of eye injury should be referred for an ophthalmologic exam (Grade D). (4) Patients with symptoms of ethylene glycol poisoning should be referred immediately for evaluation regardless of the reported dose (Grade C). (5) The absence of symptoms shortly after ingestion does not exclude a potentially toxic dose and should not be used as a triage criterion (Grade C). (6) Adults who ingest a "swallow" (10-30 mL), children who ingest more than a witnessed taste or lick, or if the amount is unknown of most ethylene glycol products should be referred immediately for evaluation. The potential toxic volume of dilute solutions (e.g., concentration <20%) is larger and can be estimated by a formula in the text (Grade C). (7) A witnessed taste or lick only by a child, or an adult who unintentionally drinks and then expectorates the product without swallowing, does not need referral (Grade C). (8) Referral is not needed if it has been >24 hours since a potentially toxic unintentional exposure, the patient has been asymptomatic, and no alcohol was co-ingested (Grade D). (9) Gastrointestinal decontamination with ipecac syrup, gastric lavage or activated charcoal is not recommended. Transportation to an emergency department should not be delayed for any decontamination procedures (Grade D). (10) Patients meeting referral criteria should be evaluated at a hospital emergency department rather than a clinic. A facility that can quickly obtain an ethylene glycol serum concentration and has alcohol or fomepizole therapy available is preferred. This referral should be guided by local poison center procedures and community resources (Grade D). (11) The administration of alcohol, fomepizole, thiamine, or pyridoxine is n

Caravati, E Martin; Erdman, Andrew R; Christianson, Gwenn; Manoguerra, Anthony S; Booze, Lisa L; Woolf, Alan D; Olson, Kent R; Chyka, Peter A; Scharman, Elizabeth J; Wax, Paul M; Keyes, Daniel C; Troutman, William G

2005-01-01

389

Does Digital Game-Based Learning Improve Student Time-on-Task Behavior and Engagement in Comparison to Alternative Instructional Strategies?  

ERIC Educational Resources Information Center

Digital Game-Based Learning (DGBL) activities were examined in comparison with effective, research-based learning strategies to observe any difference in student engagement and time-on task behavior. Experimental and control groups were randomly selected amongst the intermediate elementary school students ages 8 to 10 years old. Student…

Schaaf, Ryan

2012-01-01

390

Assessment of outdoor radiofrequency electromagnetic field exposure through hotspot localization using kriging-based sequential sampling  

SciTech Connect

In this study, a novel methodology is proposed to create heat maps that accurately pinpoint the outdoor locations with elevated exposure to radiofrequency electromagnetic fields (RF-EMF) in an extensive urban region (or, hotspots), and that would allow local authorities and epidemiologists to efficiently assess the locations and spectral composition of these hotspots, while at the same time developing a global picture of the exposure in the area. Moreover, no prior knowledge about the presence of radiofrequency radiation sources (e.g., base station parameters) is required. After building a surrogate model from the available data using kriging, the proposed method makes use of an iterative sampling strategy that selects new measurement locations at spots which are deemed to contain the most valuable information—inside hotspots or in search of them—based on the prediction uncertainty of the model. The method was tested and validated in an urban subarea of Ghent, Belgium with a size of approximately 1 km{sup 2}. In total, 600 input and 50 validation measurements were performed using a broadband probe. Five hotspots were discovered and assessed, with maximum total electric-field strengths ranging from 1.3 to 3.1 V/m, satisfying the reference levels issued by the International Commission on Non-Ionizing Radiation Protection for exposure of the general public to RF-EMF. Spectrum analyzer measurements in these hotspots revealed five radiofrequency signals with a relevant contribution to the exposure. The radiofrequency radiation emitted by 900 MHz Global System for Mobile Communications (GSM) base stations was always dominant, with contributions ranging from 45% to 100%. Finally, validation of the subsequent surrogate models shows high prediction accuracy, with the final model featuring an average relative error of less than 2 dB (factor 1.26 in electric-field strength), a correlation coefficient of 0.7, and a specificity of 0.96. -- Highlights: • We present an iterative measurement and modeling method for outdoor RF-EMF exposure. • Hotspots are rapidly identified, and accurately characterized. • An accurate graphical representation, or heat map, is created, using kriging. • Random validation shows good correlation (0.7) and low relative errors (2 dB)

Aerts, Sam, E-mail: sam.aerts@intec.ugent.be; Deschrijver, Dirk; Verloock, Leen; Dhaene, Tom; Martens, Luc; Joseph, Wout

2013-10-15

391

A population-based study on welding exposures at work and respiratory symptoms.  

PubMed

In the first European Community Respiratory Health Survey (ECRHS I), an excess asthma risk was associated with high exposure to gases and fumes, mineral and biological dusts. In a 9-year follow-up study (ECRHS II), the aim was to study if welding at work increases the risk of asthma symptoms, wheeze and chronic bronchitis symptoms. The study also aimed to identify specific welding risk factors. In a random population sample of individuals from 22 European centres in 10 countries, 316 males reported welding at work during the follow-up period. These individuals responded to a supplemental questionnaire about frequency of welding, use of different methods and materials, welding environment and respiratory protection. Cumulative exposure to welding fumes for the follow-up period was estimated by using a database on welding fume exposures. Log-binomial regression models were used to estimate prevalence ratios (PR) with 95% confidence intervals (CIs) for prevalence of asthma symptoms or asthma medication, wheeze and chronic bronchitis symptoms in relation to welding methods and welded materials as well as estimated cumulative welding fume exposure compared to an external reference group. In the study population of 316 males, 62% performed welding <1 h day(-1), 23% 1-3 h day(-1) and 15% >4 h day(-1). Welding was a common task in many occupations and only 7% of the individuals actually called themselves welders and flame cutters, while the largest groups doing welding worked in construction or were motor, agricultural and industrial mechanics and fitters. Welding at work was not associated with an increased prevalence of asthma symptoms or wheeze but there was an association with chronic bronchitis symptoms (PR = 1.33, 1.00-1.76). Using assigned cumulative exposure in tertiles showed that the lowest exposed tertile had the highest PR of bronchitis symptoms. Chronic bronchitis symptoms was significantly higher in those frequently welding in galvanized steel or iron (PR = 2.14, 1.24-3.68) and in those frequently manual welding stainless steel (PR = 1.92, 1.00-3.66). There was also an increase in the prevalence of wheeze in individuals welding painted metal (PR = 1.66, 0.99-2.78; PR = 1.83, 0.90-3.71). Welding with manual metal arc technique <1 day week(-1) showed a prevalence risk of 1.69 for wheeze (CI = 1.16-2.46). In conclusion, the present study shows an association between welding in galvanized material and stainless steel and chronic bronchitis symptoms. There was also an increased prevalence of wheeze and welding in painted metal. The results support that welding in coated material is a respiratory hazard underscoring the importance of preventive actions. PMID:18216372

Lillienberg, L; Zock, J-P; Kromhout, H; Plana, E; Jarvis, D; Torén, K; Kogevinas, M

2008-03-01

392

An Assessment of Instant Messaging Interruptions on Knowledge Workers' Task Performance in E-Learning-Based Training  

ERIC Educational Resources Information Center

The modern workplace environment is filled with interruptions due to the necessity of coworkers to communicate with each other. Studies have revealed that interruptions can disrupt the ability of a knowledge worker to concentrate on a task, which can impact task performance (TP). Communication interruptions are due, in part, to the unavoidable…

Mansi, Gary R.

2011-01-01

393

Health and Human Services Cluster. Task Analyses. Physical Therapist Aide and Physical Therapist Assistant. A Competency-Based Curriculum Guide.  

ERIC Educational Resources Information Center

Developed in Virginia, this publication contains task analysis guides to support selected tech prep programs that prepare students for careers in the health and human services cluster. Occupations profiled are physical therapist aide and physical therapist assistant. Each guide contains the following elements: (1) an occupational task list derived…

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

394

Predictive Engineering Models Based on the EPIC Architecture for a Multimodal High-Performance Human-Computer Interaction Task  

Microsoft Academic Search

Engineering models of human performance permit some aspects of usability of interface designs to be predicted from an analysis of the task, and thus they can replace to some extent expensive user-testing data. We successfully predicted human performance in telephone operator tasks with engineering models constructed in the EPIC (Executive Process-Interac- tive Control) architecture for human information processing, which is

DAVID E. KIERAS; SCOTT D. WOOD; DAVID E. MEYER

1996-01-01

395

Connecting Lines of Research on Task Model Variables, Automatic Item Generation, and Learning Progressions in Game-Based Assessment  

ERIC Educational Resources Information Center

In "How Task Features Impact Evidence from Assessments Embedded in Simulations and Games," Almond, Kim, Velasquez, and Shute have prepared a thought-provoking piece contrasting the roles of task model variables in a traditional assessment of mathematics word problems to their roles in "Newton's Playground," a game designed…

Graf, Edith Aurora

2014-01-01

396

Collaborative Learner Biographies: Or, Discovering You Had Created a Project-Based Learning Task without Realizing It  

ERIC Educational Resources Information Center

The purpose of this paper is to report on an assessment task designed to provoke pre-service teacher education students to recollect and share experiences of what enabled and frustrated their learning. The assumption underpinning the creation of this task was that: if teacher education students could, through reflection and discussion, recapture…

Saltmarsh, David

2012-01-01

397

Conceptual design of a lunar base solar power plant lunar base systems study task 3.3  

NASA Technical Reports Server (NTRS)

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.

1988-01-01

398

Truncated Lévy flights and agenda-based mobility are useful for the assessment of personal human exposure.  

PubMed

Receptor-oriented approaches can assess the individual-specific exposure to air pollution. In such an individual-based model we analyse the impact of human mobility to the personal exposure that is perceived by individuals simulated in an exemplified urban area. The mobility models comprise random walk (reference point mobility, RPM), truncated Lévy flights (TLF), and agenda-based walk (RPMA). We describe and review the general concepts and provide an inter-comparison of these concepts. Stationary and ergodic behaviour are explained and applied as well as performance criteria for a comparative evaluation of the investigated algorithms. We find that none of the studied algorithm results in purely random trajectories. TLF and RPMA prove to be suitable for human mobility modelling, because they provide conditions for very individual-specific trajectories and exposure. Suggesting these models we demonstrate the plausibility of their results for exposure to air-borne benzene and the combined exposure to benzene and nonane. PMID:21429644

Schlink, Uwe; Ragas, Ad M J

2011-01-01

399

Population-Based Biomonitoring of Exposure to Organophosphate and Pyrethroid Pesticides in New York City  

PubMed Central

Background: Organophosphates and pyrethroids are the most common classes of insecticides used in the United States. Widespread use of these compounds to control building infestations in New York City (NYC) may have caused higher exposure than in less-urban settings. Objectives: The objectives of our study were to estimate pesticide exposure reference values for NYC and identify demographic and behavioral characteristics that predict exposures. Methods: The NYC Health and Nutrition Examination Survey was a population-based, cross-sectional study conducted in 2004 among adults ? 20 years of age. It measured urinary concentrations of organophosphate metabolites [dimethylphosphate (DMP), dimethylthiophosphate (DMTP), dimethyldithiophosphate, diethylphosphate, diethylthiophosphate, and diethyldithiophosphate] in 883 participants, and pyrethroid metabolites [3-phenoxybenzoic acid (3-PBA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (trans-DCCA), 4-fluoro-3-phenoxybenzoic acid, and cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid] in 1,452 participants. We used multivariable linear regression to estimate least-squares geometric mean total dialkylphospate (?DAP) and 3-PBA concentrations across categories of predictors. Results: The dimethyl organophosphate metabolites had the highest 95th percentile concentrations (87.4 ?g/L and 74.7 ?g/L for DMP and DMTP, respectively). The highest 95th percentiles among pyrethroid metabolites were measured for 3-PBA and trans-DCCA (5.23 ?g/L and 5.94 ?g/L, respectively). Concentrations of ?DAP increased with increasing age, non-Hispanic white or black compared with Hispanic race/ethnicity, professional pesticide use, and increasing frequency of fruit consumption; they decreased with non-green vegetable consumption. Absolute differences in geometric mean urinary 3-PBA concentrations across categories of predictors were too small to be meaningful. Conclusion: Estimates of exposure to pyrethroids and dimethyl organophosphates were higher in NYC than in the United States overall, underscoring the importance of considering pest and pesticide burdens in cities when formulating pesticide use regulations. Citation: McKelvey W, Jacobson JB, Kass D, Barr DB, Davis M, Calafat AM, Aldous KM. 2013. Population-based biomonitoring of exposure to organophosphate and pyrethroid pesticides in New York City. Environ Health Perspect 121:1349–1356;?http://dx.doi.org/10.1289/ehp.1206015 PMID:24076605

Jacobson, J. Bryan; Kass, Daniel; Barr, Dana Boyd; Davis, Mark; Calafat, Antonia M.; Aldous, Kenneth M.

2013-01-01

400

[Environmental investigation of ground water contamination at Wright- Patterson Air Force Base, Ohio]. Volume 4, Health and Safety Plan (HSP); Phase 1, Task 4 Field Investigation report: Draft  

SciTech Connect

This Health and Safety Plan (HSP) was developed for the Environmental Investigation of Ground-water Contamination Investigation at Wright-Patterson Air Force Base near Dayton, Ohio, based on the projected scope of work for the Phase 1, Task 4 Field Investigation. The HSP describes hazards that may be encountered during the investigation, assesses the hazards, and indicates what type of personal protective equipment is to be used for each task performed. The HSP also addresses the medical monitoring program, decontamination procedures, air monitoring, training, site control, accident prevention, and emergency response.

Not Available

1991-10-01

401

Transport Task Force Leadership, Task 4  

SciTech Connect

The Transport Task Force (TTF) was initiated as a broad-based US magnetic fusion community activity during the fall of 1988 to focus attention on and encourage development of an increased understanding of anomalous transport in tokamaks. The overall TTF goal is to make progress on Characterizing, Understanding and Identifying how to Reduce plasma transport in tokamaks -- to CUIR transport.

Callen, J.D.

1991-07-01

402

Embrittlement of nickel-, cobalt-, and iron-base superalloys by exposure to hydrogen  

NASA Technical Reports Server (NTRS)

Five nickel-base alloys (Inconel 718, Udimet 700, Rene 41, Hastelloy X, and TD-NiCr), one cobalt-base alloy (L-605), and an iron-base alloy (A-286) were exposed in hydrogen at 0.1 MN/sq m (15 psi) at several temperatures in the range from 430 to 980 C for as long as 1000 hours. These alloys were embrittled to varying degrees by such exposures in hydrogen. Embrittlement was found to be: (1) sensitive to strain rate, (2) reversible, (3) caused by large concentrations of absorbed hydrogen, and (4) not associated with any detectable microstructural changes in the alloys. These observations are consistent with a mechanism of internal reversible hydrogen embrittlement.

Gray, H. R.

1975-01-01

403

MICA-AIR: A PARTICIPANT-BASED APPROACH TO EXPOSURE ASSESSMENT IN EPIDEMIOLOGIC AND COMMUNITY HEALTH STUDIES  

EPA Science Inventory

Objective. Epidemiologic and community health studies of traffic-related air pollution and childhood asthma have been limited by resource intensive exposure assessment techniques. The current study utilized a novel participant-based approach to collect air monitoring data f...

404

Temporal Semantics and Specification of Complex Tasks.  

National Technical Information Service (NTIS)

The formal approach to modelling and specifying complex dynamic tasks introduced is based on the assumption that complex tasks can be modelled as compositional tasks for which the dynamic aspects are essential. A compositional framework has been presented...

F. M. T. Brazier, J. Treur, N. J. E. Wijngaards, M. Willems

1994-01-01

405

Decentralized Allocation of Tasks with Delayed Commencement  

Microsoft Academic Search

In this paper we propose an approach for flexible and decentralized task allocation based on a negotia- tion protocol and applicable in case of delayed commencement of tasks. Delayed task commencement arises when an agent has to make some eort in order to start the task, e.g. a robot first has to move towards the starting position of its task

Nelis Boucke; Danny Weyns; Tom Holvoet; Koenraad Mertens

2004-01-01

406

A mathematical framework for including various sources of variability in a task-based assessment of digital breast tomosynthesis  

NASA Astrophysics Data System (ADS)

For a rigorous x-ray imaging system optimization and evaluation, the need for exploring a large space of many different system parameters is immense. However, due to the high dimensionality of the problem, it is often infeasible to evaluate many system parameters in a laboratory setting. Therefore, it is useful to utilize computer simulation tools and analytical methods to narrow down to a much smaller space of system parameters and then validate the chosen optimal parameters by laboratory measurements. One great advantage of using the simulation and analytical methods is that the impact of various sources of variability on the system's diagnostic performance can be studied separately and collectively. Previously, we have demonstrated how to separate and analyze noise sources using covariance decomposition in a task-based approach to the assessment of digital breast tomosynthesis (DBT) systems in the absence of x-ray scatter and detector blur.1, 2 In this work, we analytically extend the previous work to include x-ray scatter and detector blur. With use of computer simulation, we also investigate the use of the convolution method for approximating the scatter images of structured phantoms in comparison to those computed via Monte Carlo. The extended method is comprehensive and can be used both for exploring a large parameter space in simulation and for validating optimal parameters, chosen from a simulation study, with laboratory measurements.

Park, Subok; Badal, Andreu; Young, Stefano; Myers, Kyle J.

2012-03-01

407

A novel approach to model exposure of coastal-marine ecosystems to riverine flood plumes based on remote sensing techniques.  

PubMed

Increased loads of land-based pollutants are a major threat to coastal-marine ecosystems. Identifying the affected marine areas and the scale of influence on ecosystems is critical to assess the impacts of degraded water quality and to inform planning for catchment management and marine conservation. Studies using remotely-sensed data have contributed to our understanding of the occurrence and influence of river plumes, and to our ability to assess exposure of marine ecosystems to land-based pollutants. However, refinement of plume modeling techniques is required to improve risk assessments. We developed a novel, complementary, approach to model exposure of coastal-marine ecosystems to land-based pollutants. We used supervised classification of MODIS-Aqua true-color satellite imagery to map the extent of plumes and to qualitatively assess the dispersal of pollutants in plumes. We used the Great Barrier Reef (GBR), the world's largest coral reef system, to test our approach. We combined frequency of plume occurrence with spatially distributed loads (based on a cost-distance function) to create maps of exposure to suspended sediment and dissolved inorganic nitrogen. We then compared annual exposure maps (2007-2011) to assess inter-annual variability in the exposure of coral reefs and seagrass beds to these pollutants. We found this method useful to map plumes and qualitatively assess exposure to land-based pollutants. We observed inter-annual variation in exposure of ecosystems to pollutants in the GBR, stressing the need to incorporate a temporal component into plume exposure/risk models. Our study contributes to our understanding of plume spatial-temporal dynamics of the GBR and offers a method that can also be applied to monitor exposure of coastal-marine ecosystems to plumes and explore their ecological influences. PMID:23500022

Álvarez-Romero, Jorge G; Devlin, Michelle; Teixeira da Silva, Eduardo; Petus, Caroline; Ban, Natalie C; Pressey, Robert L; Kool, Johnathan; Roberts, Jason J; Cerdeira-Estrada, Sergio; Wenger, Amelia S; Brodie, Jon

2013-04-15

408

A group-based tasks allocation algorithm for the optimization of long leave opportunities in academic departments  

NASA Astrophysics Data System (ADS)

The general formulation of the assignment problem consists in the optimal allocation of a given set of tasks to a workforce. This problem is covered by existing literature for different domains such as distributed databases, distributed systems, transportation, packets radio networks, IT outsourcing, and teaching allocation. This paper presents a new version of the assignment problem for the allocation of academic tasks to staff members in departments with long leave opportunities. It presents the description of a workload allocation scheme and its algorithm, for the allocation of an equitable number of tasks in academic departments where long leaves are necessary.

Eyono Obono, S. D.; Basak, Sujit Kumar

2011-12-01

409

Isotretinoin exposure during pregnancy: a population-based study in The Netherlands  

PubMed Central

Objective To estimate isotretinoin exposure in Dutch pregnant women despite the implemented pregnancy prevention programme (PPP) and second, to analyse the occurrence of adverse fetal or neonatal outcomes in these isotretinoin exposed pregnancies. Design Population-based study. Setting The Netherlands. Participants A cohort of 203?962 pregnancies with onset between 1 January 1999 and 1 September 2007 consisting of 208?161 fetuses or neonates. Main outcome measures Isotretinoin exposure in the 30?days before or during pregnancy. Proportions of adverse fetal or neonatal outcomes, defined as intrauterine deaths ?16?week of gestation and neonates with major congenital anomalies. ORs with 95% CIs adjusted for maternal age were calculated to estimate the risk of adverse fetal or neonatal outcome after maternal isotretinoin exposure. Results 51 pregnancies, 2.5 (95% CI 1.9 to 3.3) per 10?000 pregnancies, were exposed to isotretinoin despite the pregnancy prevention programme. Forty-five of these pregnancies, 2.2 (95% CI 1.6 to 2.9) per 10?000 pregnancies, were exposed to isotretinoin during pregnancy and six additional women became pregnant within 30?days after isotretinoin discontinuation. In 60% of isotretinoin exposed pregnancies, women started isotretinoin while already pregnant. In five out of the 51 isotretinoin exposed pregnancies (53 fetuses), 9.4% (95% CI 1.3% to 17.6%), had an adverse fetal or neonatal outcome. The OR for adverse fetal or neonatal outcomes after isotretinoin exposure in 30?days before or during pregnancy was 2.3 (95% CI 0.9 to 5.7) after adjustment for maternal age. Conclusions Although a PPP was already implemented in 1988, we showed that isotretinoin exposed pregnancies and adverse fetal and neonatal events potentially related to the exposure still occur. These findings from the Netherlands add to the evidence that there is no full compliance to the isotretinoin PPP in many Western countries. Given the limited success of iPLEDGE, the question is which further measures are able to improve compliance. PMID:25392022

Zomerdijk, Ingeborg M; Ruiter, Rikje; Houweling, Leanne M A; Herings, Ron M C; Sturkenboom, Miriam C J M; Straus, Sabine M J M; Stricker, Bruno H

2014-01-01

410

Learning Tasks  

ERIC Educational Resources Information Center

Government budget constraints had forced the Emergency Dispatch Center (EDC) at a military installation to work with less than the normal number of staff. A Program Proposal was developed previously that had determined that a learning gap existed in the researcher's work environment at a military installation. To counter this gap, Learning Tasks

Baskas, Richard S.

2012-01-01

411

Mass Spectrometry-Based Metabolite Profiling in the Mouse Liver following Exposure to Ultraviolet B Radiation  

PubMed Central

Although many studies have been performed on the effects of ultraviolet (UV) radiation on the skin, only a limited number of reports have investigated these effects on non-skin tissue. This study aimed to describe the metabolite changes in the liver of hairless mice following chronic exposure to UVB radiation. We did not observe significant macroscopic changes or alterations in hepatic cholesterol and triglyceride levels in the liver of UVB-irradiated mice, compared with those for normal mice. In this study, we detected hepatic metabolite changes by UVB exposure and identified several amino acids, fatty acids, nucleosides, carbohydrates, phospholipids, lysophospholipids, and taurine-conjugated cholic acids as candidate biomarkers in response to UVB radiation in the mouse liver by using various mass spectrometry (MS)-based metabolite profiling including ultra-performance liquid chromatography-quadrupole time-of-flight (TOF)-MS, gas chromatography-TOF-MS and nanomate LTQ-MS. Glutamine exhibited the most dramatic change with a 5-fold increase in quantity. The results from altering several types of metabolites suggest that chronic UVB irradiation may impact significantly on major hepatic metabolism processes, despite the fact that the liver is not directly exposed to UVB radiation. MS-based metabolomic approach for determining regulatory hepatic metabolites following UV irradiation will provide a better understanding of the relationship between internal organs and UV light. PMID:25275468

Park, Hye Min; Shon, Jong Cheol; Lee, Mee Youn; Liu, Kwang-Hyeon; Kim, Jeong Kee; Lee, Sang Jun; Lee, Choong Hwan

2014-01-01

412

Siting criteria based on the prevention of deterministic effects from plutonium inhalation exposures.  

PubMed

Siting criteria are established by regulatory authorities to evaluate potential accident scenarios associated with proposed nuclear facilities. The 0.25 Sv (25 rem) siting criteria adopted in the United States has been historically based on the prevention of deterministic effects from acute, whole-body exposures. The Department of Energy has extended the applicability of this criterion to radionuclides that deliver chronic, organ-specific irradiation through the specification of a 0.25 Sv (25 rem) committed effective dose equivalent siting criterion. A methodology is developed to determine siting criteria based on the prevention of deterministic effects from inhalation intakes of radionuclides which deliver chronic, organ-specific irradiation. Revised siting criteria, expressed in terms of committed effective dose equivalent, are proposed for nuclear facilities that handle primarily plutonium compounds. The analysis determined that a siting criterion of 1.2 Sv (120 rem) committed effective dose equivalent for inhalation exposures to weapons-grade plutonium meets the historical goal of preventing deterministic effects during a facility accident scenario. The criterion also meets the Nuclear Regulatory Commission and Department of Energy Nuclear Safety Goals provided that the frequency of the accident is sufficiently low. PMID:9827508

Sorensen, S A; Low, J O

1998-12-01

413

Personalized Access to Information by Query Reformulation Based on the State of the Current Task and User Profile  

E-print Network

the transitions at time intervals with the task state changes. In this paper, a new concept of SRQ (State Reformulated Queries) is introduced and used to reformulate queries. The result obtained by SRQ is more

Sansonnet, Jean-Paul

414

A Novel Set-Shifting Modification of the Iowa Gambling Task: Flexible Emotion-Based Learning in Schizophrenia  

E-print Network

/1951; Damasio, 1996; Johnson, Kim, & Riss, 1985; LeDoux, 2000; Rogers et al., 1999; Tranel & Damasio, 1993 Task (IGT; Bechara et al., 1994; Happaney, Zelazo, & Stuss, 2004; though see also Bickel, De

Park, Sohee

415

Arsenic Exposure and Impaired Lung Function. Findings from a Large Population-based Prospective Cohort Study  

PubMed Central

Rationale: Exposure to arsenic through drinking water has been linked to respiratory symptoms, obstructive lung diseases, and mortality from respiratory diseases. Limited evidence for the deleterious effects on lung function exists among individuals exposed to a high dose of arsenic. Objectives: To determine the deleterious effects on lung function that exist among individuals exposed to a high dose of arsenic. Methods: In 950 individuals who presented with any respiratory symptom among a population-based cohort of 20,033 adults, we evaluated the association between arsenic exposure, measured by well water and urinary arsenic concentrations measured at baseline, and post-bronchodilator–administered pulmonary function assessed during follow-up. Measurements and Main Results: For every one SD increase in baseline water arsenic exposure, we observed a lower level of FEV1 (?46.5 ml; P < 0.0005) and FVC (?53.1 ml; P < 0.01) in regression models adjusted for age, sex, body mass index, smoking, socioeconomic status, betel nut use, and arsenical skin lesions status. Similar inverse relationships were observed between baseline urinary arsenic and FEV1 (?48.3 ml; P < 0.005) and FVC (?55.2 ml; P < 0.01) in adjusted models. Our analyses also demonstrated a dose-related decrease in lung function with increasing levels of baseline water and urinary arsenic. This association remained significant in never-smokers and individuals without skin lesions, and was stronger in male smokers. Among male smokers and individuals with skin lesions, every one SD increase in water arsenic was related to a significant reduction of FEV1 (?74.4 ml, P < 0.01; and ?116.1 ml, P < 0.05) and FVC (?72.8 ml, P = 0.02; and ?146.9 ml, P = 0.004), respectively. Conclusions: This large population-based study confirms that arsenic exposure is associated with impaired lung function and the deleterious effect is evident at low- to moderate-dose range. PMID:23848239

Parvez, Faruque; Chen, Yu; Yunus, Mahbub; Olopade, Christopher; Segers, Stephanie; Slavkovich, Vesna; Argos, Maria; Hasan, Rabiul; Ahmed, Alauddin; Islam, Tariqul; Akter, Mahmud M.; Graziano, Joseph H.

2013-01-01

416

Evaluating terrain based criteria for snow avalanche exposure ratings using GIS  

NASA Astrophysics Data System (ADS)

Snow avalanche terrain in backcountry regions of Canada is increasingly being assessed based upon the Avalanche Terrain Exposure Scale (ATES). ATES is a terrain based classification introduced in 2004 by Parks Canada to identify "simple", "challenging" and "complex" backcountry areas. The ATES rating system has been applied to well over 200 backcountry routes, has been used in guidebooks, trailhead signs and maps and is part of the trip planning component of the AVALUATOR™, a simple decision-support tool for backcountry users. Geographic Information Systems (GIS) offers a means to model and visualize terrain based criteria through the use of digital elevation model (DEM) and land cover data. Primary topographic variables such as slope, aspect and curvature are easily derived from a DEM and are compatible with the equivalent evaluation criteria in ATES. Other components of the ATES classification are difficult to extract from a DEM as they are not strictly terrain based. An overview is provided of the terrain variables that can be generated from DEM and land cover data; criteria from ATES which are not clearly terrain based are identified for further study or revision. The second component of this investigation was the development of an algorithm for inputting suitable ATES criteria into a GIS, thereby mimicking the process avalanche experts use when applying the ATES classification to snow avalanche terrain. GIS based classifications were compared to existing expert assessments for validity. The advantage of automating the ATES classification process through GIS is to assist avalanche experts with categorizing and mapping remote backcountry terrain.

Delparte, Donna; Jamieson, Bruce; Waters, Nigel

2010-05-01

417

Human exposure to mycotoxins and their masked forms through cereal-based foods in Belgium.  

PubMed

In the present study, a quantitative dietary exposure assessment of mycotoxins and their masked forms was conducted on a national representative sample of the Belgian population using the contamination data of cereal-based foods. Cereal-based food products (n=174) were analysed for the occurrence of deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, zearalenone, ?-zearalenol, ?-zearalenol, T-2-toxin, HT-2-toxin, and their respective masked forms, including, deoxynivalenol-3-glucoside, zearalenone-4-glucoside, ?-zearalenol-4-glucoside, ?-zearalenol-4-glucoside and zearalenone-4-sulfate. Fibre-enriched bread, bran-enriched bread, breakfast cereals, popcorn and oatmeal were collected in Belgian supermarkets according to a structured sampling plan and analysed during the period from April 2010 to October 2011. The habitual intake of these food groups was estimated from a national representative food intake survey. According to a probabilistic exposure analysis, the mean (and P95) mycotoxin intake for the sum of the deoxynivalenol-equivalents, zearalenone-equivalents, and the sum of HT-2-and T-2-toxin for all cereal-based foods was 0.1162 (0.4047, P95), 0.0447 (0.1568, P95) and 0.0258 (0.0924, P95) ?g kg(-1)body weight day(-1), respectively. These values were below the tolerable daily intake (TDI) levels for deoxynivalenol, zearalenone and the sum of T-2 and HT-2 toxin (1.0, 0.25 and 0.1 ?g kg(-1)body weight day(-1), respectively). The absolute level exceeding the TDI for all cereal-based foods was calculated, and recorded 0.85%, 2.75% and 4.11% of the Belgian population, respectively. PMID:23454655

De Boevre, Marthe; Jacxsens, Liesbeth; Lachat, Carl; Eeckhout, Mia; Di Mavungu, José Diana; Audenaert, Kris; Maene, Peter; Haesaert, Geert; Kolsteren, Patrick; De Meulenaer, Bruno; De Saeger, Sarah

2013-04-26

418

Encouraging Innovation in a Modern Foreign Language Initial Teacher Education Programme: What Do Beginning Teachers Make of Task-Based Language Teaching?  

ERIC Educational Resources Information Center

Task-based language teaching (TBLT) is an innovative learner-centred and experiential approach to modern foreign language (MFL) teaching and learning that is not without controversy in the secondary MFL classroom. This article considers one secondary-level initial teacher education programme in New Zealand in which, following school curriculum…

East, Martin

2014-01-01

419

Effects of a Perseverative Interest-Based Token Economy on Challenging and On-Task Behavior in a Child with Autism  

ERIC Educational Resources Information Center

We compared the effects of a token economy intervention that either did or did not include the perseverative interests of a 7-year-old boy with autism. An alternating treatment design revealed that the perseverative interest-based tokens were more effective at decreasing challenging behavior and increasing on-task behavior than tokens absent the…

Carnett, Amarie; Raulston, Tracy; Lang, Russell; Tostanoski, Amy; Lee, Allyson; Sigafoos, Jeff; Machalicek, Wendy

2014-01-01

420

Disaggregation of nation-wide dynamic population exposure estimates in The Netherlands: Applications of activity-based transport models  

NASA Astrophysics Data System (ADS)

Traditional exposure studies that link concentrations with population data do not always take into account the temporal and spatial variations in both concentrations and population density. In this paper we present an integrated model chain for the determination of nation-wide exposure estimates that incorporates temporally and spatially resolved information about people's location and activities (obtained from an activity-based transport model) and about ambient pollutant concentrations (obtained from a dispersion model). To the best of our knowledge, it is the first time that such an integrated exercise was successfully carried out in a fully operational modus for all models under consideration. The evaluation of population level exposure in The Netherlands to NO 2 at different time-periods, locations, for different subpopulations (gender, socio-economic status) and during different activities (residential, work, transport, shopping) is chosen as a case-study to point out the new features of this methodology. Results demonstrate that, by neglecting people's travel behaviour, total average exposure to NO 2 will be underestimated by 4% and hourly exposure results can be underestimated by more than 30%. A more detailed exposure analysis reveals the intra-day variations in exposure estimates and the presence of large exposure differences between different activities (traffic > work > shopping > home) and between subpopulations (men > women, low socio-economic class > high socio-economic class). This kind of exposure analysis, disaggregated by activities or by subpopulations, per time of day, provides useful insight and information for scientific and policy purposes. It demonstrates that policy measures, aimed at reducing the overall (average) exposure concentration of the population may impact in a different way depending on the time of day or the subgroup considered. From a scientific point of view, this new approach can be used to reduce exposure misclassification.

Beckx, Carolien; Int Panis, Luc; Uljee, Inge; Arentze, Theo; Janssens, Davy; Wets, Geert