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Sample records for binaural task dynamic

  1. A dynamic binaural synthesis system for investigation into situational awareness for truck drivers

    DEFF Research Database (Denmark)

    Christensen, Flemming; Møller, Anders Kalsgaard; Hammershøi, Dorte

    2016-01-01

    into the reason for this point to cognitive phenomena such as change blindness, where more visual information won’t help. For other professional vehicle operators such as pilots, auditory solutions adding to a higher situational awareness has proven valuable. This paper describes the development of a dynamic...... binaural synthesis system for investigation into situational awareness for truck drivers. The system is built around several software components enabling the 3D positioning of an auditory representation of a bicycle. The sound is played back over headphones to the truck driver whose head movements......, and initial practical experience with the system used in real driving situations will be discussed....

  2. The technology of binaural listening

    CERN Document Server

    2013-01-01

    This book reports on the application of advanced models of the human binaural hearing system in modern technology, among others, in the following areas:  binaural analysis of aural scenes, binaural de-reverberation, binaural quality assessment of audio channels, loudspeakers and performance spaces, binaural perceptual coding, binaural processing in hearing aids and cochlea implants, binaural systems in robots, binaural/tactile human-machine interfaces, speech-intelligibility prediction in rooms and/or multi-speaker scenarios. An introduction to binaural modeling and an outlook to the future are provided. Further, the book features a MATLAB toolbox to enable readers to construct their own dedicated binaural models on demand.

  3. The impact of binaural beats on creativity

    Directory of Open Access Journals (Sweden)

    Susan A. Reedijk

    2013-11-01

    Full Text Available Human creativity relies on a multitude of cognitive processes, some of which are influenced by the neurotransmitter dopamine. This suggests that creativity could be enhanced by interventions that either modulate the production or transmission of dopamine directly, or affect dopamine-driven processes. In the current study we hypothesized that creativity can be influenced by means of binaural beats, an auditory illusion that is considered a form of cognitive entrainment that operates through stimulating neuronal phase locking. We aimed to investigate whether binaural beats affect creative performance at all, whether they affect divergent thinking, convergent thinking, or both, and whether possible effects may be mediated by the individual striatal dopamine level. Binaural beats were presented at alpha and gamma frequency. Participants completed a divergent and a convergent thinking task to assess two important functions of creativity, and filled out the Positive And Negative Affect Scale – mood State questionnaire (PANAS-S and affect grid to measure current mood. Dopamine levels in the striatum were estimated using spontaneous eye blink rates (EBRs. Results showed that binaural beats, regardless of the presented frequency, can affect divergent but not convergent thinking. Individuals with low EBRs mostly benefitted from alpha binaural beat stimulation, while individuals with high EBR were unaffected or even impaired by both alpha and gamma binaural beats. This suggests that binaural beats, and possibly other forms of cognitive entrainment, are not suited for a one-size-fits-all approach, and that individual cognitive-control systems need to be taken into account when studying cognitive enhancement methods.

  4. Evaluation of dynamic binaural reproduction system for live transmitted xylophone recording

    DEFF Research Database (Denmark)

    Madsen, Esben; Markovic, Milos; Olesen, Søren Krarup;

    2012-01-01

    For a special teaching application of the telepresence research project BEAMING, a scenario of a remote teacher (the Visitor) teaching a local student to play a xylophone through an embodiment is defined. In order to achieve this, a system is required to record, transmit and render the sound...... of the xylophone to the teacher in a dynamic scene. In an implementation of such a system, the xylophone is recorded using a mono recording technique. The signal is then processed to spread out the sound of the distributed sound source as multiple point sources in the virtual scene experienced by the Visitor...

  5. Directional dependence of binaural loudness

    DEFF Research Database (Denmark)

    Ellermeier, Wolfgang; Sivonen, Ville Pekka

    2006-01-01

    of experiments determining the effect of sound incidence angle on loudness[1,2,3,4]. The basic experiment to be reported on here was conducted in an anechoic chamber, in which loudspeakers were mounted to present sounds from a number of directions both in the horizontal, and median planes. The...... subject’s task was to produce a loudness match to a frontal reference location, and matches were obtained via a two-interval adaptive forced-choice procedure. Narrow-band noises were used, in order to investigate the frequency-specific effects of direction on loudness. Furthermore, individual HRTFs were...... measured for each incidence angle, in order to relate the changes in actual at-ear exposure to the observed changes in loudness as a function of sound incidence. Combining the listening-test data with the physical measurements, an attempt was made to model the binaural summation underlying the directional...

  6. A new perspective on binaural integration using response time methodology: super capacity revealed in conditions of binaural masking release.

    Science.gov (United States)

    Lentz, Jennifer J; He, Yuan; Townsend, James T

    2014-01-01

    This study applied reaction-time based methods to assess the workload capacity of binaural integration by comparing reaction time (RT) distributions for monaural and binaural tone-in-noise detection tasks. In the diotic contexts, an identical tone + noise stimulus was presented to each ear. In the dichotic contexts, an identical noise was presented to each ear, but the tone was presented to one of the ears 180° out of phase with respect to the other ear. Accuracy-based measurements have demonstrated a much lower signal detection threshold for the dichotic vs. the diotic conditions, but accuracy-based techniques do not allow for assessment of system dynamics or resource allocation across time. Further, RTs allow comparisons between these conditions at the same signal-to-noise ratio. Here, we apply a reaction-time based capacity coefficient, which provides an index of workload efficiency and quantifies the resource allocations for single ear vs. two ear presentations. We demonstrate that the release from masking generated by the addition of an identical stimulus to one ear is limited-to-unlimited capacity (efficiency typically less than 1), consistent with less gain than would be expected by probability summation. However, the dichotic presentation leads to a significant increase in workload capacity (increased efficiency)-most specifically at lower signal-to-noise ratios. These experimental results provide further evidence that configural processing plays a critical role in binaural masking release, and that these mechanisms may operate more strongly when the signal stimulus is difficult to detect, albeit still with nearly 100% accuracy. PMID:25202254

  7. A New Perspective on Binaural Integration Using Response Time Methodology: Super Capacity Revealed in Conditions of Binaural Masking Release

    Directory of Open Access Journals (Sweden)

    Jennifer eLentz

    2014-08-01

    Full Text Available This study applied reaction-time based methods to assess the workload capacity of binaural integration by comparing reaction time distributions for monaural and binaural tone-in-noise detection tasks. In the diotic contexts, an identical tone + noise stimulus was presented to each ear. In the dichotic contexts, an identical noise was presented to each ear, but the tone was presented to one of the ears 180o out of phase with respect to the other ear. Accuracy-based measurements have demonstrated a much lower signal detection threshold for the dichotic versus the diotic conditions, but accuracy-based techniques do not allow for assessment of system dynamics or resource allocation across time. Further, reaction times allow comparisons between these conditions at the same signal-to-noise ratio. Here, we apply a reaction-time based capacity coefficient, which provides an index of workload efficiency and quantifies the resource allocations for single ear versus two ear presentations. We demonstrate that the release from masking generated by the addition of an identical stimulus to one ear is limited-to-unlimited capacity (efficiency typically less than 1, consistent with less gain than would be expected by probability summation. However, the dichotic presentation leads to a significant increase in workload capacity (increased efficiency – most specifically at lower signal-to-noise ratios. These experimental results provide further evidence that configural processing plays a critical role in binaural masking release, and that these mechanisms may operate more strongly when the signal stimulus is difficult to detect, albeit still with nearly 100% accuracy.

  8. Instructional Multiple Binaural Stethoscope

    Directory of Open Access Journals (Sweden)

    Catalina C. Platon

    2015-12-01

    Full Text Available The stethoscope is an acoustic medical device for auscultation where human ear plays significant part. Long before doctors practiced immediate auscultation meaning placing ear directly on patient’s body by Salinsky (1990, then monaural introduced by Laennec; later binaural, Comins’s invention and Cammann developed further. Several decades numerous innovations made predominantly over chestpiece some had drawbacks. Dr Littman introduced teaching stethoscope with two headset and researcher utilized as prior art.Experimental research method used and the study aimed to determine accuracy and measurement of speed of the device in terms of systolic and diastolic blood pressure and acceptability of user. The subjects were 19 clients and 27 nursing students, government /private registered nurses. The device are comparable to single binaural stethoscope in accuracy performance; speed of sound, former is slightly higher than the latter but still considered as normal; the device are acceptable to users; the utility model have no significant difference in accuracy performance and speed measurements of systolic and diastolic. The utility model may be tried in any acoustic activities and may be pilot tested to the Universities animal science courses, veterinary medicine other Colleges of Nursing and all health allied courses.

  9. Designing for dynamic task allocation

    NARCIS (Netherlands)

    Dongen, C.J.G. van; Maanen, P.P. van

    2005-01-01

    Future platforms are envisioned in which human-machine teams are able to share and trade tasks as demands in situations change. It seems that human-machine coordination has not received the attention it deserves by past and present approaches to task allocation. In this paper a simple way to make co

  10. A new perspective on binaural integration using response time methodology: super capacity revealed in conditions of binaural masking release

    OpenAIRE

    Lentz, Jennifer J.; He, Yuan; Townsend, James T.

    2014-01-01

    This study applied reaction-time based methods to assess the workload capacity of binaural integration by comparing reaction time (RT) distributions for monaural and binaural tone-in-noise detection tasks. In the diotic contexts, an identical tone + noise stimulus was presented to each ear. In the dichotic contexts, an identical noise was presented to each ear, but the tone was presented to one of the ears 180° out of phase with respect to the other ear. Accuracy-based measurements have demon...

  11. A New Perspective on Binaural Integration Using Response Time Methodology: Super Capacity Revealed in Conditions of Binaural Masking Release

    OpenAIRE

    Jennifer Lentz; Townsend, James T.

    2014-01-01

    This study applied reaction-time based methods to assess the workload capacity of binaural integration by comparing reaction time distributions for monaural and binaural tone-in-noise detection tasks. In the diotic contexts, an identical tone + noise stimulus was presented to each ear. In the dichotic contexts, an identical noise was presented to each ear, but the tone was presented to one of the ears 180o out of phase with respect to the other ear. Accuracy-based measurements have demonstra...

  12. Monaural and interaural intensity discrimination: Level effects and the ``binaural advantage''

    Science.gov (United States)

    Stellmack, Mark A.; Viemeister, Neal F.; Byrne, Andrew J.

    2004-08-01

    This study examined whether the level effects seen in monaural intensity discrimination (Weber's law and the ``near miss'') in a two-interval task are also observed in discrimination of interaural intensity differences (IIDs) in a single-interval task. Both tasks were performed for various standard levels of 4-kHz pure tones and broadband noise. The Weber functions (10 log ΔI/I versus I in dB) in the monaural and binaural conditions were parallel. For noise, the Weber functions had slopes close to zero (Weber's law) while the Weber functions for the tones had a mean slope of -0.089 (near miss). The near miss for the monaural and binaural tasks with tones was eliminated when a high-pass masker was gated with the listening intervals. The near-miss was also observed for 250- and 1000-Hz tones in the binaural task despite overall decreased sensitivity to changes in IID at 1000 Hz. The binaural thresholds showed a small (about 2-dB) advantage over monaural thresholds only in the broadband noise conditions. More important, however, is the fact that the level effects seen monaurally are also seen binaurally. This suggests that the basic mechanisms responsible for Weber's law and the near miss are common to monaural and binaural processing.

  13. Eye Movements Reveal Dynamics of Task Control

    Science.gov (United States)

    Mayr, Ulrich; Kuhns, David; Rieter, Miranda

    2013-01-01

    With the goal to determine the cognitive architecture that underlies flexible changes of control settings, we assessed within-trial and across-trial dynamics of attentional selection by tracking of eye movements in the context of a cued task-switching paradigm. Within-trial dynamics revealed a switch-induced, discrete delay in onset of…

  14. Cortical subnetwork dynamics during human language tasks.

    Science.gov (United States)

    Collard, Maxwell J; Fifer, Matthew S; Benz, Heather L; McMullen, David P; Wang, Yujing; Milsap, Griffin W; Korzeniewska, Anna; Crone, Nathan E

    2016-07-15

    Language tasks require the coordinated activation of multiple subnetworks-groups of related cortical interactions involved in specific components of task processing. Although electrocorticography (ECoG) has sufficient temporal and spatial resolution to capture the dynamics of event-related interactions between cortical sites, it is difficult to decompose these complex spatiotemporal patterns into functionally discrete subnetworks without explicit knowledge of each subnetwork's timing. We hypothesized that subnetworks corresponding to distinct components of task-related processing could be identified as groups of interactions with co-varying strengths. In this study, five subjects implanted with ECoG grids over language areas performed word repetition and picture naming. We estimated the interaction strength between each pair of electrodes during each task using a time-varying dynamic Bayesian network (tvDBN) model constructed from the power of high gamma (70-110Hz) activity, a surrogate for population firing rates. We then reduced the dimensionality of this model using principal component analysis (PCA) to identify groups of interactions with co-varying strengths, which we term functional network components (FNCs). This data-driven technique estimates both the weight of each interaction's contribution to a particular subnetwork, and the temporal profile of each subnetwork's activation during the task. We found FNCs with temporal and anatomical features consistent with articulatory preparation in both tasks, and with auditory and visual processing in the word repetition and picture naming tasks, respectively. These FNCs were highly consistent between subjects with similar electrode placement, and were robust enough to be characterized in single trials. Furthermore, the interaction patterns uncovered by FNC analysis correlated well with recent literature suggesting important functional-anatomical distinctions between processing external and self-produced speech. Our

  15. Binaural Rendering in MPEG Surround

    Directory of Open Access Journals (Sweden)

    Kristofer Kjörling

    2008-04-01

    Full Text Available This paper describes novel methods for evoking a multichannel audio experience over stereo headphones. In contrast to the conventional convolution-based approach where, for example, five input channels are filtered using ten head-related transfer functions, the current approach is based on a parametric representation of the multichannel signal, along with either a parametric representation of the head-related transfer functions or a reduced set of head-related transfer functions. An audio scene with multiple virtual sound sources is represented by a mono or a stereo downmix signal of all sound source signals, accompanied by certain statistical (spatial properties. These statistical properties of the sound sources are either combined with statistical properties of head-related transfer functions to estimate “binaural parameters” that represent the perceptually relevant aspects of the auditory scene or used to create a limited set of combined head-related transfer functions that can be applied directly on the downmix signal. Subsequently, a binaural rendering stage reinstates the statistical properties of the sound sources by applying the estimated binaural parameters or the reduced set of combined head-related transfer functions directly on the downmix. If combined with parametric multichannel audio coders such as MPEG Surround, the proposed methods are advantageous over conventional methods in terms of perceived quality and computational complexity.

  16. A high-density EEG investigation into steady state binaural beat stimulation.

    Directory of Open Access Journals (Sweden)

    Peter Goodin

    Full Text Available Binaural beats are an auditory phenomenon that has been suggested to alter physiological and cognitive processes including vigilance and brainwave entrainment. Some personality traits measured by the NEO Five Factor Model have been found to alter entrainment using pulsing light stimuli, but as yet no studies have examined if this occurs using steady state presentation of binaural beats for a relatively short presentation of two minutes. This study aimed to examine if binaural beat stimulation altered vigilance or cortical frequencies and if personality traits were involved. Thirty-one participants were played binaural beat stimuli designed to elicit a response at either the Theta (7 Hz or Beta (16 Hz frequency bands while undertaking a zero-back vigilance task. EEG was recorded from a high-density electrode cap. No significant differences were found in vigilance or cortical frequency power during binaural beat stimulation compared to a white noise control period. Furthermore, no significant relationships were detected between the above and the Big Five personality traits. This suggests a short presentation of steady state binaural beats are not sufficient to alter vigilance or entrain cortical frequencies at the two bands examined and that certain personality traits were not more susceptible than others.

  17. Parametric binaural synthesis: Background, applications and standards

    NARCIS (Netherlands)

    Breebaart, D.J.; Nater, F.; Kohlrausch, A.G.

    2010-01-01

    The amount of information present in HRTFs and the required processing capabilities for real-time and inter-active binaural rendering have long been a challenge for many applications for binaural rendering. More recently, parametric methods to capture the perceptually-relevant information from HRTFs

  18. Control of earphone produced binaural signals

    DEFF Research Database (Denmark)

    Hammershøi, Dorte; Hoffmann, Pablo F.

    2011-01-01

    While most people keep a high attention to the significance of the binaural recording method, whether it is e.g. individual or non-individual (as e.g. artificial head recording), many pay less attention to the type of earphone used to reproduce the binaural signals, and to the accurate control of...

  19. DYNAMIC TASK SCHEDULING ON MULTICORE AUTOMOTIVE ECUS

    Directory of Open Access Journals (Sweden)

    Geetishree Mishra

    2014-12-01

    Full Text Available Automobile manufacturers are controlled by stringent govt. regulations for safety and fuel emissions and motivated towards adding more advanced features and sophisticated applications to the existing electronic system. Ever increasing customer’s demands for high level of comfort also necessitate providing even more sophistication in vehicle electronics system. All these, directly make the vehicle software system more complex and computationally more intensive. In turn, this demands very high computational capability of the microprocessor used in electronic control unit (ECU. In this regard, multicore processors have already been implemented in some of the task rigorous ECUs like, power train, image processing and infotainment. To achieve greater performance from these multicore processors, parallelized ECU software needs to be efficiently scheduled by the underlaying operating system for execution to utilize all the computational cores to the maximum extent possible and meet the real time constraint. In this paper, we propose a dynamic task scheduler for multicore engine control ECU that provides maximum CPU utilization, minimized preemption overhead, minimum average waiting time and all the tasks meet their real time deadlines while compared to the static priority scheduling suggested by Automotive Open Systems Architecture (AUTOSAR

  20. Dynamic Task Scheduling on Multicore Automotive ECUs

    Directory of Open Access Journals (Sweden)

    Geetishree Mishra

    2014-12-01

    Full Text Available Automobile manufacturers are controlled by stringen t govt. regulations for safety and fuel emissions a nd motivated towards adding more advanced features and sophisticated applications to the existing electro nic system. Ever increasing customer’s demands for high level of comfort also necessitate providing even m ore sophistication in vehicle electronics system. All t hese, directly make the vehicle software system mor e complex and computationally more intensive. In turn , this demands very high computational capability o f the microprocessor used in electronic control unit (ECU. In this regard, multicore processors have already been implemented in some of the task rigoro us ECUs like, power train, image processing and infotainment. To achieve greater performance from t hese multicore processors, parallelized ECU softwar e needs to be efficiently scheduled by the underlayin g operating system for execution to utilize all the computational cores to the maximum extent possible and meet the real time constraint. In this paper, w e propose a dynamic task scheduler for multicore engi ne control ECU that provides maximum CPU utilization, minimized preemption overhead, minimum average waiting time and all the tasks meet their real time deadlines while compared to the static pr iority scheduling suggested by Automotive Open Syst ems Architecture (AUTOSAR.

  1. Setup for demonstrating interactive binaural synthesis for telepresence applications

    DEFF Research Database (Denmark)

    Madsen, Esben; Olesen, Søren Krarup; Markovic, Milos;

    2011-01-01

    3 main tasks: Tracking coordinates are combined to calculate directions. This is handled by sharing "global" coordinates across the sites and adding local changes with a low latency, ending with a "direction of sound" for each source. Audio is recorded and transmitted over network. Here bandwidth....... The combined system was evaluated by the user experience at the demonstration, with the overall conclusion that interactive binaural synthesis is an important aspect of a fully immersive telepresence application and that we should continue in this direction examining different approaches....

  2. Time-Varying Distortions of Binaural Information by Bilateral Hearing Aids

    Science.gov (United States)

    Rodriguez, Francisco A.; Portnuff, Cory D. F.; Goupell, Matthew J.; Tollin, Daniel J.

    2016-01-01

    In patients with bilateral hearing loss, the use of two hearing aids (HAs) offers the potential to restore the benefits of binaural hearing, including sound source localization and segregation. However, existing evidence suggests that bilateral HA users’ access to binaural information, namely interaural time and level differences (ITDs and ILDs), can be compromised by device processing. Our objective was to characterize the nature and magnitude of binaural distortions caused by modern digital behind-the-ear HAs using a variety of stimuli and HA program settings. Of particular interest was a common frequency-lowering algorithm known as nonlinear frequency compression, which has not previously been assessed for its effects on binaural information. A binaural beamforming algorithm was also assessed. Wide dynamic range compression was enabled in all programs. HAs were placed on a binaural manikin, and stimuli were presented from an arc of loudspeakers inside an anechoic chamber. Stimuli were broadband noise bursts, 10-Hz sinusoidally amplitude-modulated noise bursts, or consonant–vowel–consonant speech tokens. Binaural information was analyzed in terms of ITDs, ILDs, and interaural coherence, both for whole stimuli and in a time-varying sense (i.e., within a running temporal window) across four different frequency bands (1, 2, 4, and 6 kHz). Key findings were: (a) Nonlinear frequency compression caused distortions of high-frequency envelope ITDs and significantly reduced interaural coherence. (b) For modulated stimuli, all programs caused time-varying distortion of ILDs. (c) HAs altered the relationship between ITDs and ILDs, introducing large ITD–ILD conflicts in some cases. Potential perceptual consequences of measured distortions are discussed. PMID:27698258

  3. Dynamical Models of Task Organization in Social Insect Colonies.

    Science.gov (United States)

    Kang, Yun; Theraulaz, Guy

    2016-05-01

    The organizations of insect societies, such as division of labor, task allocation, collective regulation, mass action responses, have been considered as main reasons for the ecological success. In this article, we propose and study a general modeling framework that includes the following three features: (a) the average internal response threshold for each task (the internal factor); (b) social network communications that could lead to task switching (the environmental factor); and (c) dynamical changes of task demands (the external factor). Since workers in many social insect species exhibit age polyethism, we also extend our model to incorporate age polyethism in which worker task preferences change with age. We apply our general modeling framework to the cases of two task groups: the inside colony task versus the outside colony task. Our analytical study of the models provides important insights and predictions on the effects of colony size, social communication, and age-related task preferences on task allocation and division of labor in the adaptive dynamical environment. Our study implies that the smaller size colony invests its resource for the colony growth and allocates more workers in the risky tasks such as foraging while the larger colony shifts more workers to perform the safer tasks inside the colony. Social interactions among different task groups play an important role in shaping task allocation depending on the relative cost and demands of the tasks. PMID:27125656

  4. Augmented metacognition addressing dynamic allocation of tasks requiring visual attention

    NARCIS (Netherlands)

    Bosse, T.; Doesburg, W. van; Maanen, P.P. van; Treur, J.

    2007-01-01

    This paper discusses the use of cognitive models as augmented metacognition on task allocation for tasks requiring visual attention. In the domain of naval warfare, the complex and dynamic nature of the environment makes that one has to deal with a large number of tasks in parallel. Therefore, human

  5. Comparing Binaural Pre-processing Strategies II

    Directory of Open Access Journals (Sweden)

    Regina M. Baumgärtel

    2015-12-01

    Full Text Available Several binaural audio signal enhancement algorithms were evaluated with respect to their potential to improve speech intelligibility in noise for users of bilateral cochlear implants (CIs. 50% speech reception thresholds (SRT50 were assessed using an adaptive procedure in three distinct, realistic noise scenarios. All scenarios were highly nonstationary, complex, and included a significant amount of reverberation. Other aspects, such as the perfectly frontal target position, were idealized laboratory settings, allowing the algorithms to perform better than in corresponding real-world conditions. Eight bilaterally implanted CI users, wearing devices from three manufacturers, participated in the study. In all noise conditions, a substantial improvement in SRT50 compared to the unprocessed signal was observed for most of the algorithms tested, with the largest improvements generally provided by binaural minimum variance distortionless response (MVDR beamforming algorithms. The largest overall improvement in speech intelligibility was achieved by an adaptive binaural MVDR in a spatially separated, single competing talker noise scenario. A no-pre-processing condition and adaptive differential microphones without a binaural link served as the two baseline conditions. SRT50 improvements provided by the binaural MVDR beamformers surpassed the performance of the adaptive differential microphones in most cases. Speech intelligibility improvements predicted by instrumental measures were shown to account for some but not all aspects of the perceptually obtained SRT50 improvements measured in bilaterally implanted CI users.

  6. DYNAMIC TASK PARTITIONING MODEL IN PARALLEL COMPUTING

    Directory of Open Access Journals (Sweden)

    Javed Ali

    2012-04-01

    Full Text Available Parallel computing systems compose task partitioning strategies in a true multiprocessing manner. Such systems share the algorithm and processing unit as computing resources which leads to highly inter process communications capabilities. The main part of the proposed algorithm is resource management unit which performs task partitioning and co-scheduling .In this paper, we present a technique for integrated task partitioning and co-scheduling on the privately owned network. We focus on real-time and non preemptive systems. A large variety of experiments have been conducted on the proposed algorithm using synthetic and real tasks. Goal of computation model is to provide a realistic representation of the costs of programming The results show the benefit of the task partitioning. The main characteristics of our method are optimal scheduling and strong link between partitioning, scheduling and communication. Some important models for task partitioning are also discussed in the paper. We target the algorithm for task partitioning which improve the inter process communication between the tasks and use the recourses of the system in the efficient manner. The proposed algorithm contributes the inter-process communication cost minimization amongst the executing processes.

  7. Better Decision Making in Complex, Dynamic Tasks

    Science.gov (United States)

    Qudrat-Ullah, Hassan

    Complex managerial problems abound. For instance, project costs continue to overrun, friendly fire events, where a fighter plane bombs its own troops on ground, appear unavoidable, and overexploitation of renewables continues unabated. In essence, managers and policymakers today face problems that are increasingly complex, and dynamic. Therefore, the need for effective and efficient decisional aids is always on the rise.

  8. Beamforming under Quantization Errors in Wireless Binaural Hearing Aids

    Directory of Open Access Journals (Sweden)

    Kees Janse

    2008-09-01

    Full Text Available Improving the intelligibility of speech in different environments is one of the main objectives of hearing aid signal processing algorithms. Hearing aids typically employ beamforming techniques using multiple microphones for this task. In this paper, we discuss a binaural beamforming scheme that uses signals from the hearing aids worn on both the left and right ears. Specifically, we analyze the effect of a low bit rate wireless communication link between the left and right hearing aids on the performance of the beamformer. The scheme is comprised of a generalized sidelobe canceller (GSC that has two inputs: observations from one ear, and quantized observations from the other ear, and whose output is an estimate of the desired signal. We analyze the performance of this scheme in the presence of a localized interferer as a function of the communication bit rate using the resultant mean-squared error as the signal distortion measure.

  9. Beamforming under Quantization Errors in Wireless Binaural Hearing Aids

    Directory of Open Access Journals (Sweden)

    Srinivasan Sriram

    2008-01-01

    Full Text Available Improving the intelligibility of speech in different environments is one of the main objectives of hearing aid signal processing algorithms. Hearing aids typically employ beamforming techniques using multiple microphones for this task. In this paper, we discuss a binaural beamforming scheme that uses signals from the hearing aids worn on both the left and right ears. Specifically, we analyze the effect of a low bit rate wireless communication link between the left and right hearing aids on the performance of the beamformer. The scheme is comprised of a generalized sidelobe canceller (GSC that has two inputs: observations from one ear, and quantized observations from the other ear, and whose output is an estimate of the desired signal. We analyze the performance of this scheme in the presence of a localized interferer as a function of the communication bit rate using the resultant mean-squared error as the signal distortion measure.

  10. Analysis and Modeling of Control Tasks in Dynamic Systems

    DEFF Research Database (Denmark)

    Ursem, Rasmus Kjær; Krink, Thiemo; Jensen, Mikkel Thomas;

    2002-01-01

    -case generators (TCGs), which requires a systematic analysis of dynamic optimization tasks. So far, only a few TCGs have been suggested. Our investigation leads to the conclusion that these TCGs are not capable of generating realistic dynamic benchmark tests. The result of our research is the design of a new TCG...

  11. Dynamic Task Optimization in Remote Diabetes Monitoring Systems

    Science.gov (United States)

    Suh, Myung-kyung; Woodbridge, Jonathan; Moin, Tannaz; Lan, Mars; Alshurafa, Nabil; Samy, Lauren; Mortazavi, Bobak; Ghasemzadeh, Hassan; Bui, Alex; Ahmadi, Sheila; Sarrafzadeh, Majid

    2016-01-01

    Diabetes is the seventh leading cause of death in the United States, but careful symptom monitoring can prevent adverse events. A real-time patient monitoring and feedback system is one of the solutions to help patients with diabetes and their healthcare professionals monitor health-related measurements and provide dynamic feedback. However, data-driven methods to dynamically prioritize and generate tasks are not well investigated in the domain of remote health monitoring. This paper presents a wireless health project (WANDA) that leverages sensor technology and wireless communication to monitor the health status of patients with diabetes. The WANDA dynamic task management function applies data analytics in real-time to discretize continuous features, applying data clustering and association rule mining techniques to manage a sliding window size dynamically and to prioritize required user tasks. The developed algorithm minimizes the number of daily action items required by patients with diabetes using association rules that satisfy a minimum support, confidence and conditional probability thresholds. Each of these tasks maximizes information gain, thereby improving the overall level of patient adherence and satisfaction. Experimental results from applying EM-based clustering and Apriori algorithms show that the developed algorithm can predict further events with higher confidence levels and reduce the number of user tasks by up to 76.19 %.

  12. Prospective Memory and Task Interference in a Continuous Monitoring Dynamic Display Task

    Science.gov (United States)

    Loft, Shayne; Remington, Roger W.

    2010-01-01

    Theories and methods from the prospective memory literature were used to anticipate how individuals would maintain and retrieve intentions in a continuous monitoring dynamic display task. Participants accepted aircraft into sectors and detected aircraft conflicts during an air traffic control simulation. They were sometimes required to substitute…

  13. Heuristic Scheduling Algorithm Oriented Dynamic Tasks for Imaging Satellites

    Directory of Open Access Journals (Sweden)

    Maocai Wang

    2014-01-01

    Full Text Available Imaging satellite scheduling is an NP-hard problem with many complex constraints. This paper researches the scheduling problem for dynamic tasks oriented to some emergency cases. After the dynamic properties of satellite scheduling were analyzed, the optimization model is proposed in this paper. Based on the model, two heuristic algorithms are proposed to solve the problem. The first heuristic algorithm arranges new tasks by inserting or deleting them, then inserting them repeatedly according to the priority from low to high, which is named IDI algorithm. The second one called ISDR adopts four steps: insert directly, insert by shifting, insert by deleting, and reinsert the tasks deleted. Moreover, two heuristic factors, congestion degree of a time window and the overlapping degree of a task, are employed to improve the algorithm’s performance. Finally, a case is given to test the algorithms. The results show that the IDI algorithm is better than ISDR from the running time point of view while ISDR algorithm with heuristic factors is more effective with regard to algorithm performance. Moreover, the results also show that our method has good performance for the larger size of the dynamic tasks in comparison with the other two methods.

  14. Relating binaural pitch perception to the individual listener's auditory profile

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten

    2012-01-01

    The ability of eight normal-hearing listeners and fourteen listeners with sensorineural hearing loss to detect and identify pitch contours was measured for binaural-pitch stimuli and salience-matched monaurally detectable pitches. In an effort to determine whether impaired binaural pitch percepti...

  15. Comparison of binaural microphones for externalization of sounds

    DEFF Research Database (Denmark)

    Cubick, Jens; Sánchez Rodríguez, C.; Song, Wookeun;

    2015-01-01

    or with microphones placed inside the ear canals of a person. In this study, binaural room impulse responses (BRIRs) were measured with several commercially available binaural microphones, both placed inside the listeners’ ears (individual BRIR) and on a head and torso simulator (generic BRIR). The degree...

  16. Task-Based Cohesive Evolution of Dynamic Brain Networks

    Science.gov (United States)

    Davison, Elizabeth

    2014-03-01

    Applications of graph theory to neuroscience have resulted in significant progress towards a mechanistic understanding of the brain. Functional network representation of the brain has linked efficient network structure to psychometric intelligence and altered configurations with disease. Dynamic graphs provide us with tools to further study integral properties of the brain; specifically, the mathematical convention of hyperedges has allowed us to study the brain's cross-linked structure. Hyperedges capture the changes in network structure by identifying groups of brain regions with correlation patterns that change cohesively through time. We performed a hyperedge analysis on functional MRI data from 86 subjects and explored the cohesive evolution properties of their functional brain networks as they performed a series of tasks. Our results establish the hypergraph as a useful measure in understanding functional brain dynamics over tasks and reveal characteristic differences in the co-evolution structure of task-specific networks.

  17. Dynamic Task Allocation for Human-Robot Teams

    NARCIS (Netherlands)

    Giele, T.R.A.; Mioch, T.; Neerincx, M.A.; Meyer, J.J.C.

    2015-01-01

    Artificial agents, such as robots, are increasingly deployed for teamwork in dynamic, high-demand environments. This paper presents a framework, which applies context information to establish task (re)allocations that improve human-robot team’s performance. Based on the framework, a model for adapti

  18. A Binaural Cochlear Implant Sound Coding Strategy Inspired by the Contralateral Medial Olivocochlear Reflex

    OpenAIRE

    Enrique A Lopez-Poveda; Eustaquio-Martín, Almudena; Stohl, Joshua S.; Wolford, Robert D.; Schatzer, Reinhold; Wilson, Blake S.

    2015-01-01

    Objectives: In natural hearing, cochlear mechanical compression is dynamically adjusted via the efferent medial olivocochlear reflex (MOCR). These adjustments probably help understanding speech in noisy environments and are not available to the users of current cochlear implants (CIs). The aims of the present study are to: (1) present a binaural CI sound processing strategy inspired by the control of cochlear compression provided by the contralateral MOCR in natural hearing; and (2) assess th...

  19. Integrated Task and Data Parallel Support for Dynamic Applications

    Directory of Open Access Journals (Sweden)

    James M. Rehg

    1999-01-01

    Full Text Available There is an emerging class of real‐time interactive applications that require the dynamic integration of task and data parallelism. An example is the Smart Kiosk, a free‐standing computer device that provides information and entertainment to people in public spaces. The kiosk interface is computationally demanding: It employs vision and speech sensing and an animated graphical talking face for output. The computational demands of an interactive kiosk can vary widely with the number of customers and the state of the interaction. Unfortunately this makes it difficult to apply current techniques for integrated task and data parallel computing, which can produce optimal decompositions for static problems. Using experimental results from a color‐based people tracking module, we demonstrate the existence of a small number of distinct operating regimes in the kiosk application. We refer to this type of program behavior as constrained dynamism. An application exhibiting constrained dynamism can execute efficiently by dynamically switching among a small number of statically determined fixed data parallel strategies. We present a novel framework for integrating task and data parallelism for applications that exhibit constrained dynamism. Our solution has been implemented using Stampede, a cluster programming system developed at the Cambridge Research Laboratory.

  20. Exploiting Dynamic Workload Variation in Low Energy Preemptive Task Scheduling

    CERN Document Server

    Leung, Lap-Fai; Hu, Xiaobo Sharon

    2011-01-01

    A novel energy reduction strategy to maximally exploit the dynamic workload variation is proposed for the offline voltage scheduling of preemptive systems. The idea is to construct a fully-preemptive schedule that leads to minimum energy consumption when the tasks take on approximately the average execution cycles yet still guarantees no deadline violation during the worst-case scenario. End-time for each sub-instance of the tasks obtained from the schedule is used for the on-line dynamic voltage scaling (DVS) of the tasks. For the tasks that normally require a small number of cycles but occasionally a large number of cycles to complete, such a schedule provides more opportunities for slack utilization and hence results in larger energy saving. The concept is realized by formulating the problem as a Non-Linear Programming (NLP) optimization problem. Experimental results show that, by using the proposed scheme, the total energy consumption at runtime is reduced by as high as 60% for randomly generated task set...

  1. Binaural Glimpses at the Cocktail Party?

    Science.gov (United States)

    Lingner, Andrea; Grothe, Benedikt; Wiegrebe, Lutz; Ewert, Stephan D

    2016-10-01

    Humans often have to focus on a single target sound while ignoring competing maskers in everyday situations. In such conditions, speech intelligibility (SI) is improved when a target speaker is spatially separated from a masker (spatial release from making, SRM) compared to situations where both are co-located. Such asymmetric spatial configurations lead to a 'better-ear effect' with improved signal-to-noise ratio (SNR) at one ear. However, maskers often surround the listener leading to more symmetric configurations where better-ear effects are absent in a long-term, wideband sense. Nevertheless, better-ear glimpses distributed across time and frequency persist and were suggested to account for SRM (Brungart and Iyer 2012). Here, speech reception was assessed using symmetric masker configurations while varying the spatio-temporal distribution of potential better-ear glimpses. Listeners were presented with a frontal target and eight single-talker maskers in four different symmetrical spatial configurations. Compared to the reference condition with co-located target and maskers, an SRM of up to 6 dB was observed. The SRM persisted when the frequency range of the maskers above or below 1500 Hz was replaced with stationary speech-shaped noise. Comparison to a recent short-time binaural SI model showed that better-ear glimpses can account for half the observed SRM, while binaural interaction utilizing phase differences is required to explain the other half. PMID:27412529

  2. Robust Satellite Scheduling Approach for Dynamic Emergency Tasks

    Directory of Open Access Journals (Sweden)

    Xuejun Zhai

    2015-01-01

    Full Text Available Earth observation satellites play a significant role in rapid responses to emergent events on the Earth’s surface, for example, earthquakes. In this paper, we propose a robust satellite scheduling model to address a sequence of emergency tasks, in which both the profit and robustness of the schedule are simultaneously maximized in each stage. Both the multiobjective genetic algorithm NSGA2 and rule-based heuristic algorithm are employed to obtain solutions of the model. NSGA2 is used to obtain a flexible and highly robust initial schedule. When every set of emergency tasks arrives, a combined algorithm called HA-NSGA2 is used to adjust the initial schedule. The heuristic algorithm (HA is designed to insert these tasks dynamically to the waiting queue of the initial schedule. Then the multiobjective genetic algorithm NSGA2 is employed to find the optimal solution that has maximum revenue and robustness. Meanwhile, to improve the revenue and resource utilization, we adopt a compact task merging strategy considering the duration of task execution in the heuristic algorithm. Several experiments are used to evaluate the performance of HA-NSGA2. All simulation experiments show that the performance of HA-NSGA2 is significantly improved.

  3. Comparisons between Binaural In-situ Recordings and Auralizations

    DEFF Research Database (Denmark)

    Saher, Konca; Rindel, Jens Holger; Nijs, Lau

    2006-01-01

    -architectural design. This paper deals with comparison between binaural in-situ recordings and auralizations obtained from computer simulations. Listening tests and questionnaires were prepared from auralizations to compare with the reference binaural recordings. The difficulties in evaluation of auralization quality...... are discussed. The results indicate that although auralizations and binaural recordings evoke different aural perception auralization is a strong tool to assess the acoustical environment before the space is built. Two commercial programs are used for the auralizations. (ODEON and CATT-Acoustics)...

  4. Binaural dereverberation based on interaural coherence histograms

    DEFF Research Database (Denmark)

    Westermann, Adam; Buchholz, Jorg M.; Dau, Torsten

    2013-01-01

    A binaural dereverberation algorithm is presented that utilizes the properties of the interaural coherence (IC) inspired by the concepts introduced in Allen et al. [J. Acoust. Soc. Am. 62, 912-915 (1977)]. The algorithm introduces a non-linear sigmoidal coherence-to-gain mapping that is controlled...... by an online estimate of the present coherence statistics. The algorithm automatically adapts to a given acoustic environment and provides a stronger dereverberation effect than the original method presented in Allen et al. [J. Acoust. Soc. Am. 62, 912-915 (1977)] in most acoustic conditions. The...... Allen et al. were considered as reference systems. The results revealed that the proposed coherence-based approach is most successful in acoustic scenarios that exhibit a significant spread in the coherence distribution where direct sound and reverberation can be segregated. This dereverberation...

  5. Dynamic Monitoring Reveals Motor Task Characteristics in Prehistoric Technical Gestures.

    Directory of Open Access Journals (Sweden)

    Johannes Pfleging

    Full Text Available Reconstructing ancient technical gestures associated with simple tool actions is crucial for understanding the co-evolution of the human forelimb and its associated control-related cognitive functions on the one hand, and of the human technological arsenal on the other hand. Although the topic of gesture is an old one in Paleolithic archaeology and in anthropology in general, very few studies have taken advantage of the new technologies from the science of kinematics in order to improve replicative experimental protocols. Recent work in paleoanthropology has shown the potential of monitored replicative experiments to reconstruct tool-use-related motions through the study of fossil bones, but so far comparatively little has been done to examine the dynamics of the tool itself. In this paper, we demonstrate that we can statistically differentiate gestures used in a simple scraping task through dynamic monitoring. Dynamics combines kinematics (position, orientation, and speed with contact mechanical parameters (force and torque. Taken together, these parameters are important because they play a role in the formation of a visible archaeological signature, use-wear. We present our new affordable, yet precise methodology for measuring the dynamics of a simple hide-scraping task, carried out using a pull-to (PT and a push-away (PA gesture. A strain gage force sensor combined with a visual tag tracking system records force, torque, as well as position and orientation of hafted flint stone tools. The set-up allows switching between two tool configurations, one with distal and the other one with perpendicular hafting of the scrapers, to allow for ethnographically plausible reconstructions. The data show statistically significant differences between the two gestures: scraping away from the body (PA generates higher shearing forces, but requires greater hand torque. Moreover, most benchmarks associated with the PA gesture are more highly variable than in

  6. Physiological evidence of interpersonal dynamics in a cooperative production task.

    Science.gov (United States)

    Mønster, Dan; Håkonsson, Dorthe Døjbak; Eskildsen, Jacob Kjær; Wallot, Sebastian

    2016-03-15

    Recent research suggests that shared behavioral dynamics during interpersonal interaction are indicative of subjective and objective outcomes of the interaction, such as feelings of rapport and success of performance. The role of shared physiological dynamics to quantify interpersonal interaction, however, has received comparatively little attention. In the present study, we investigate the coordination dynamics of multiple psychophysiological measures and their utility in capturing emotional dynamics in teams. We use data from an experiment where teams of three people built origami boats together in an assembly-line manner while their heart rate, skin conductance, and facial muscle activity were recorded. Our results show that physiological synchrony of skin conductance measures and eletromyographic measures of the corrugator supercilii develops spontaneously among team members during this cooperative production task. Moreover, high team synchrony is found indicative of team cohesion, while low team synchrony is found indicative of a teams' decision to adopt a new behavior across multiple production sessions. We conclude that team-level measures of synchrony offer new and complementary information compared to measures of individual levels of physiological activity. PMID:26773466

  7. Physiological evidence of interpersonal dynamics in a cooperative production task.

    Science.gov (United States)

    Mønster, Dan; Håkonsson, Dorthe Døjbak; Eskildsen, Jacob Kjær; Wallot, Sebastian

    2016-03-15

    Recent research suggests that shared behavioral dynamics during interpersonal interaction are indicative of subjective and objective outcomes of the interaction, such as feelings of rapport and success of performance. The role of shared physiological dynamics to quantify interpersonal interaction, however, has received comparatively little attention. In the present study, we investigate the coordination dynamics of multiple psychophysiological measures and their utility in capturing emotional dynamics in teams. We use data from an experiment where teams of three people built origami boats together in an assembly-line manner while their heart rate, skin conductance, and facial muscle activity were recorded. Our results show that physiological synchrony of skin conductance measures and eletromyographic measures of the corrugator supercilii develops spontaneously among team members during this cooperative production task. Moreover, high team synchrony is found indicative of team cohesion, while low team synchrony is found indicative of a teams' decision to adopt a new behavior across multiple production sessions. We conclude that team-level measures of synchrony offer new and complementary information compared to measures of individual levels of physiological activity.

  8. Dynamics of the central bottleneck: dual-task and task uncertainty.

    Directory of Open Access Journals (Sweden)

    Mariano Sigman

    2006-07-01

    Full Text Available Why is the human brain fundamentally limited when attempting to execute two tasks at the same time or in close succession? Two classical paradigms, psychological refractory period (PRP and task switching, have independently approached this issue, making significant advances in our understanding of the architecture of cognition. Yet, there is an apparent contradiction between the conclusions derived from these two paradigms. The PRP paradigm, on the one hand, suggests that the simultaneous execution of two tasks is limited solely by a passive structural bottleneck in which the tasks are executed on a first-come, first-served basis. The task-switching paradigm, on the other hand, argues that switching back and forth between task configurations must be actively controlled by a central executive system (the system controlling voluntary, planned, and flexible action. Here we have explicitly designed an experiment mixing the essential ingredients of both paradigms: task uncertainty and task simultaneity. In addition to a central bottleneck, we obtain evidence for active processes of task setting (planning of the appropriate sequence of actions and task disengaging (suppression of the plan set for the first task in order to proceed with the next one. Our results clarify the chronometric relations between these central components of dual-task processing, and in particular whether they operate serially or in parallel. On this basis, we propose a hierarchical model of cognitive architecture that provides a synthesis of task-switching and PRP paradigms.

  9. Implante coclear Digisonic SP® Binaural: acesso coronal tunelizado Digisonic SP® Binaural cochlear implant: the coronal tunneled approach

    Directory of Open Access Journals (Sweden)

    Guilherme Machado de Carvalho

    2013-06-01

    Full Text Available O implante coclear é um grande avanço no tratamento da surdez. Há grandes evidências que a audição bilateral traz diversas vantagens ao ser humano e muito mais quando se trata de audição binaural. OBJETIVO: Este artigo tem por objetivo descrever o primeiro caso operado no Brasil, sendo o terceiro país das Américas (México e Colômbia a realizar, com implante binaural Neurelec Digisonic SP® demonstrando a técnica cirúrgica. MÉTODO: Descrição da técnica cirúrgica. RESULTADOS: Ver técnica cirúrgica. Procedimento ocorreu sem intercorrências. DISCUSSÃO: O efeito "squelch", a somação binaural, a localização da fonte sonora e o efeito sombra da cabeça são umas das principais razões que justificam a superioridade da reabilitação binaural. O custo do tratamento deve ser levado em conta em políticas de saúde pública. CONCLUSÃO: Custo do implante coclear é um dos grandes limitadores da bilateralidade na reabilitação desse grupo de pacientes, porém, com essa tecnologia, é possível solucionar esse problema, expondo o paciente a poucos riscos, com o uso de uma técnica cirúrgica pouco invasiva.Cochlear implants represent a significant breakthrough in the treatment of hearing loss. Evidence indicates bilateral hearing brings significant benefits to patients, particularly when binaural hearing is offered. OBJECTIVE: To describe the first case of implantation of a Digisonic SP® Binaural Neurelec device in Brazil (the third implant placed in the Americas, after Mexico and Colombia and the chosen surgical approach. METHOD: Description of a surgical approach. RESULTS: The procedure was successfully completed. DISCUSSION: The squelch effect, binaural summation, location of the sound source, and the shadow effect of the head are listed among the reasons to explain the superiority of binaural rehabilitation. Cost of treatment must be considered in the development of public health policies. CONCLUSION: The cost of cochlear

  10. Acceptability of binaural hearing aids: a cross-over study.

    OpenAIRE

    Stephens, S D; Callaghan, D E; Hogan, S.; Meredith, R.; Rayment, A; Davis, A

    1991-01-01

    Using screening questionnaires we were able to detect individuals aged 50-65 years with hearing disability in a general practice population. Those who had better ear hearing levels of 30 dB or worse were invited to take place in a cross-over study comparing the acceptability of a monaural or binaural hearing-aid fitting. Fifty-five per cent ultimately opted for a binaural fitting and had greater hearing disability and worse mean hearing levels than those who opted for a monaural fitting. They...

  11. Binaural pitch perception in normal-hearing and hearing-impaired listeners

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten

    2007-01-01

    -pitch perception and performance in measures of spectral and temporal resolution. Reduced frequency discrimination appeared to be linked to poorer melody recognition skills. Reduced frequency selectivity was also found to impede the perception of binaural-pitch stimuli. Overall, binaural-pitch stimuli might......The effects of hearing impairment on the perception of binaural-pitch stimuli were investigated. Several experiments were performed with normal-hearing and hearing-impaired listeners, including detection and discrimination of binaural pitch, and melody recognition using different types of binaural...

  12. Prefrontal Dynamics Underlying Rapid Instructed Task Learning Reverse with Practice

    Science.gov (United States)

    Cole, Michael W.; Bagic, Anto; Kass, Robert; Schneider, Walter

    2011-01-01

    The ability to rapidly reconfigure our minds to perform novel tasks is important for adapting to an ever-changing world, yet little is understood about its basis in the brain. Furthermore, it is unclear how this kind of task preparation changes with practice. Previous research suggests that prefrontal cortex (PFC) is essential when preparing to perform either novel or practiced tasks. Building upon recent evidence that PFC is organized in an anterior-to-posterior hierarchy, we postulated that novel and practiced task preparation would differentiate hierarchically distinct regions within PFC across time. Specifically, we hypothesized and confirmed using functional magnetic resonance imaging and magnetoencephalography with humans that novel task preparation is a bottom-up process that involves lower-level rule representations in dorsolateral PFC (DLPFC) before a higher-level rule-integrating task representation in anterior PFC (aPFC). In contrast, we identified a complete reversal of this activity pattern during practiced task preparation. Specifically, we found that practiced task preparation is a top-down process that involves a higher-level rule-integrating task representation (recalled from long-term memory) in aPFC before lower-level rule representations in DLPFC. These findings reveal two distinct yet highly inter-related mechanisms for task preparation, one involving task set formation from instructions during rapid instructed task learning and the other involving task set retrieval from long-term memory to facilitate familiar task performance. These two mechanisms demonstrate the exceptional flexibility of human PFC as it rapidly reconfigures cognitive brain networks to implement a wide variety of possible tasks. PMID:20962245

  13. Efficiency of brainwave entrainment by binaural beats in reducing anxiety

    Directory of Open Access Journals (Sweden)

    Ahmad Alipoor

    2014-04-01

    Full Text Available Background: Anxiety is a fundamental phenomenon that is a common symptom in all mental disorders. The aim of the present study was to assess the effect of brainwave entrainment on anxiety reduction using binaural beats. Methods: In this experimental double-blind study, 30 employees were selected from an engineering research firm through random sampling and replacement and divided into two groups: control group and experimental group. All participants completed the Spielberger’s State-Trait Anxiety Inventory (STAI. Then, the experimental group listened to binaural beats which was recorded on a non-vocal piece of music for 4 weeks, 3 sessions each week. Each session lasted about 20 minutes. At the same time, the control group listened to the background music without any entrainment sound. At the end, both groups completed the anxiety questionnaire and the anxiety scores of both groups obtained before and after intervention were analyzed by ANCOVA. Results: The findings showed that the brainwave entrainment using binaural beats led to the significant reduction of state anxiety (P<0.001 and trait anxiety (P<0.018. Conclusion: Brainwave entrainment using binaural beats is an effective factor in decreasing state and trait anxiety; so, it can be used to reduce anxiety in mental health centers.

  14. Processing of Binaural Pitch Stimuli in Hearing-Impaired Listeners

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten

    2009-01-01

    hearingloss; 3: retro-cochlear impairment) were asked to identify the pitch contour of series of five notes of equal duration, ranging from 523 to 784 Hz, played either with Huggins’ binaural pitch stimuli (BP) or perceptually similar, but monaurally detectable, pitches (MP). All subjects from groups 1 and 2...

  15. Binaural pitch perception in hearing-impaired listeners

    DEFF Research Database (Denmark)

    Dau, Torsten; Santurette, Sébastien; Strelcyk, Olaf

    2007-01-01

    When two white noises differing only in phase in a particular frequency range are presented simultaneously each to one of our ears, a pitch sensation may be perceived inside the head. This phenomenon, called ’binaural pitch’ or ’dichotic pitch’, can be produced by frequency-dependent interaural p...

  16. The Developmental Dynamics of Task-Avoidant Behavior and Math Performance in Kindergarten and Elementary School

    Science.gov (United States)

    Hirvonen, Riikka; Tolvanen, Asko; Aunola, Kaisa; Nurmi, Jari-Erik

    2012-01-01

    Besides cognitive factors, children's learning at school may be influenced by more dynamic phenomena, such as motivation and achievement-related task-avoidant behavior. The present study examined the developmental dynamics of task-avoidant behavior and math performance from kindergarten to Grade 4. A total of 225 children were tested for their…

  17. Effects of a standing and three dynamic workstations on computer task performance and cognitive function tests

    NARCIS (Netherlands)

    Commissaris, D.A.C.M.; Könemann, R.; Hiemstra-van Mastrigt, S.; Burford, E.M.; Botter, J.; Douwes, M.; Ellegast, R.P.

    2014-01-01

    Sedentary work entails health risks. Dynamic (or active) workstations, at which computer tasks can be combined with physical activity, may reduce the risks of sedentary behaviour. The aim of this study was to evaluate short term task performance while working on three dynamic workstations: a treadmi

  18. The developmental dynamics of task-avoidant behavior and math performance in kindergarten and elementary school

    OpenAIRE

    Hirvonen, Riikka; Tolvanen, Asko; Aunola, Kaisa; Nurmi, Jari-Erik

    2012-01-01

    Besides cognitive factors, children's learning at school may be influenced by more dynamic phenomena, such as motivation and achievement-related task-avoidant behavior. The present study examined the developmental dynamics of task-avoidant behavior and math performance from kindergarten to Grade 4. A total of 225 children were tested for their arithmetic skills in kindergarten and in Grades 1, 2, and 4 of elementary school. Children's task-avoidant behavior in learning situations was rated by...

  19. The effect of overlap-masking on binaural reverberant word intelligibility

    Science.gov (United States)

    Libbey, Brad; Rogers, Peter H.

    2004-11-01

    Reverberation interferes with the ability to understand speech in rooms. Overlap-masking explains this degradation by assuming reverberant phonemes endure in time and mask subsequent reverberant phonemes. Most listeners benefit from binaural listening when reverberation exists, indicating that the listener's binaural system processes the two channels to reduce the reverberation. This paper investigates the hypothesis that the binaural word intelligibility advantage found in reverberation is a result of binaural overlap-masking release with the reverberation acting as masking noise. The tests utilize phonetically balanced word lists (ANSI-S3.2 1989), that are presented diotically and binaurally with recorded reverberation and reverberation-like noise. A small room, 62 m3, reverberates the words. These are recorded using two microphones without additional noise sources. The reverberation-like noise is a modified form of these recordings and has a similar spectral content. It does not contain binaural localization cues due to a phase randomization procedure. Listening to the reverberant words binaurally improves the intelligibility by 6.0% over diotic listening. The binaural intelligibility advantage for reverberation-like noise is only 2.6%. This indicates that binaural overlap-masking release is insufficient to explain the entire binaural word intelligibility advantage in reverberation. .

  20. Modeling dynamic tactical behaviors in COMBATXXI using Hierarchical Task Networks

    OpenAIRE

    Donaldson, Michael J.

    2014-01-01

    Approved for public release; distribution is unlimited Defining accurate representations of group behaviors in simulations is an expensive, time-consuming task. One reason for this is that previously produced behaviors are often not reusable within other scenarios or simulations. Using Hierarchical Task Networks (HTNs) to model military behaviors is a promising technique for addressing this problem. HTNs provide a methodology for linking tactical behaviors, and offer a potential system for...

  1. Physiological evidence of interpersonal dynamics in a cooperative production task

    DEFF Research Database (Denmark)

    Mønster, Dan; Håkonsson, Dorthe Døjbak; Eskildsen, Jacob Kjær;

    2016-01-01

    Recent research suggests that shared behavioral dynamics during interpersonal interaction are indicative of subjective and objective outcomes of the interaction, such as feelings of rapport and success of performance. The role of shared physiological dynamics to quantify interpersonal interaction...

  2. Relating the absence of binaural pitch percept to retro-cochlear impairment

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten

    that the salience of binaural pitch was affected by hearing impairment. Specifically, for subjects with a sensorineural impairment, binaural pitch perception was weaker than the normal-hearing average but the pitch sensation was immediately present. In contrast, no binaural pitch sensation at all was......Binaural pitch stimuli, created by introducing an interaural phase difference over a narrow band of otherwise diotic white noise, produce an immediate tonal sensation with a pitch close to the centre of the phase-shifted band. In Santurette and Dau [Hear. Res. 223(1-2):29-47, 2007], it was shown...... cognitive abilities, were obtained in order to investigate the correlation between these outcomes and results from the binaural pitch test. As no spectral cues are provided by binaural pitch stimuli, their perception is expected to heavily depend on the acuity of fine structure coding and the accuracy of...

  3. Auditory cortical processing: Binaural interaction in healthy and ROBO1-deficient subjects

    OpenAIRE

    LamminmÀki, Satu

    2012-01-01

    Two functioning ears provide clear advantages over monaural listening. During natural binaural listening, robust brain-level interaction occurs between the slightly different inputs from the left and the right ear. Binaural interaction requires convergence of inputs from the two ears somewhere in the auditory system, and it therefore relies on midline crossing of auditory pathways, a fundamental property of the mammalian central nervous system. Binaural interaction plays a significant ro...

  4. The effect of cochlear nonlinearities on binaural masking level differences

    DEFF Research Database (Denmark)

    Le Goff, Nicolas; Kohlrausch, Armin

    Background The binaural masking level difference (BMLD) has been shown to be constant (10−15dB) for masker spectrum levels from 70dB/Hz down to 30−40dB/Hz and to gradually decrease with lower levels (McFadden, 1968; Hall and Harvey, 1984). The decrease at low levels was larger in an asymmetric...... that the difference in BMLD between the symmetric and the two asymmetric conditions is constant, in line with the experimental data. Conclusion A model was proposed to account for the effect of level asymmetry on BMLD. The modeling results suggest that cochlear nonlinearites affect the analysis of binaural cues a  at...

  5. Impact of monaural frequency compression on binaural fusion at the brainstem level.

    Science.gov (United States)

    Klauke, Isabelle; Kohl, Manuel C; Hannemann, Ronny; Kornagel, Ulrich; Strauss, Daniel J; Corona-Strauss, Farah I

    2015-08-01

    A classical objective measure for binaural fusion at the brainstem level is the so-called β-wave of the binaural interaction component (BIC) in the auditory brainstem response (ABR). However, in some cases it appeared that a reliable detection of this component still remains a challenge. In this study, we investigate the wavelet phase synchronization stability (WPSS) of ABR data for the analysis of binaural fusion and compare it to the BIC. In particular, we examine the impact of monaural nonlinear frequency compression on binaural fusion. As the auditory system is tonotopically organized, an interaural frequency mismatch caused by monaural frequency compression could negatively effect binaural fusion. In this study, only few subjects showed a detectable β-wave and in most cases only for low ITDs. However, we present a novel objective measure for binaural fusion that outperforms the current state-of-the-art technique (BIC): the WPSS analysis showed a significant difference between the phase stability of the sum of the monaurally evoked responses and the phase stability of the binaurally evoked ABR. This difference could be an indicator for binaural fusion in the brainstem. Furthermore, we observed that monaural frequency compression could indeed effect binaural fusion, as the WPSS results for this condition vary strongly from the results obtained without frequency compression.

  6. Exploiting Dynamics in robotic arms with repetitive tasks

    NARCIS (Netherlands)

    Plooij, M.C.

    2015-01-01

    Since the industrial revolution, machines have taken over many tasks from humans, increasing labor productivity and prosperity. In the 20th century, the introduction of robots created a second wave of automation, increasing the labor productivity even further. In order to create a third wave of auto

  7. The dynamics of development on the Dimensional Change Card Sorting task

    NARCIS (Netherlands)

    B.M.C.W. van Bers; I. Visser; T.J.P. van Schijndel; D.J. Mandell; M.E.J. Raijmakers

    2011-01-01

    A widely used paradigm to study cognitive flexibility in preschoolers is the Dimensional Change Card Sorting (DCCS) task. The developmental dynamics of DCCS performance was studied in a cross-sectional design (N = 93, 3 to 5 years of age) using a computerized version of the standard DCCS task. A mod

  8. Seeing is Believing: Formalising False-Belief Tasks in Dynamic Epistemic Logic

    DEFF Research Database (Denmark)

    Bolander, Thomas

    2014-01-01

    In this paper we show how to formalise false-belief tasks like the Sally-Anne task and the second-order chocolate task in Dynamic Epistemic Logic (DEL). False-belief tasks are used to test the strength of the Theory of Mind (ToM) of humans, that is, a human’s ability to attribute mental states......-belief tasks. In this paper, the approach is to use DEL as a formal framework for representing ToM, and use reasoning in DEL to solve false-belief tasks. In addition to formalising several false-belief tasks in DEL, the paper introduces some extensions of DEL itself: edge-conditioned event models...

  9. Monitoring cognitive and emotional processes through pupil and cardiac response during dynamic versus logical task.

    Science.gov (United States)

    Causse, Mickaël; Sénard, Jean-Michel; Démonet, Jean François; Pastor, Josette

    2010-06-01

    The paper deals with the links between physiological measurements and cognitive and emotional functioning. As long as the operator is a key agent in charge of complex systems, the definition of metrics able to predict his performance is a great challenge. The measurement of the physiological state is a very promising way but a very acute comprehension is required; in particular few studies compare autonomous nervous system reactivity according to specific cognitive processes during task performance and task related psychological stress is often ignored. We compared physiological parameters recorded on 24 healthy subjects facing two neuropsychological tasks: a dynamic task that require problem solving in a world that continually evolves over time and a logical task representative of cognitive processes performed by operators facing everyday problem solving. Results showed that the mean pupil diameter change was higher during the dynamic task; conversely, the heart rate was more elevated during the logical task. Finally, the systolic blood pressure seemed to be strongly sensitive to psychological stress. A better taking into account of the precise influence of a given cognitive activity and both workload and related task-induced psychological stress during task performance is a promising way to better monitor operators in complex working situations to detect mental overload or pejorative stress factor of error. PMID:19816770

  10. Dynamics of task-set carry-over: evidence from eye-movement analyses.

    Science.gov (United States)

    Kikumoto, Atsushi; Hubbard, Jason; Mayr, Ulrich

    2016-06-01

    Trial-to-trial carry-over of task sets (i.e., task-set inertia) is often considered as a primary reason for task-switch costs. Yet, we know little about the dynamics of such carry-over effects, in particular how much they are driven by the most recent trial rather than characterized by a more continuous memory gradient. Using eye-tracking, we examined in a 3-task, switching paradigm whether there is a greater probability of non-target fixations to stimuli associated with the previously relevant attentional set than to those associated with the less-recent set. Indeed, we found strong evidence for more interference (expressed in terms of non-target fixations) from recent than from less-recent tasks and that in particular the interference from pre-switch trials contributed substantially to the overall pattern of response-time switch costs. Moreover, task-set carry-over was dominated by the most-recent trial when subjects could expect task repetitions (with a 33 % switch rate). In comparison, when tasks were selected randomly (with a 66 % switch rate), interference from the most recent trial decreased, whereas interference from less-recent trials increased. In sum, carry-over interference dynamics were characterized both by a gradual recency gradient and expectations about task-transition probabilities. Beyond that, there was little evidence for a unique role of the most-recent trial. PMID:26415999

  11. Binaural Integrated Active Noise Control and Noise Reduction in Hearing Aids

    DEFF Research Database (Denmark)

    Serizel, Romain; Moonen, Marc; Wouters, Jan;

    2013-01-01

    This paper presents a binaural approach to integrated active noise control and noise reduction in hearing aids and aims at demonstrating that a binaural setup indeed provides significant advantages in terms of the number of noise sources that can be compensated for and in terms of the causality...

  12. Sound Source Distance Estimation in Rooms based on Statistical Properties of Binaural Signals

    DEFF Research Database (Denmark)

    Georganti, Eleftheria; May, Tobias; van de Par, Steven;

    2013-01-01

    A novel method for the estimation of the distance of a sound source from binaural speech signals is proposed. The method relies on several statistical features extracted from such signals and their binaural cues. Firstly, the standard deviation of the difference of the magnitude spectra of the left...

  13. A machine-hearing system exploiting head movements for binaural sound localisation in reverberant conditions

    DEFF Research Database (Denmark)

    May, Tobias; Ma, Ning; Wierstorf, Hagen;

    2015-01-01

    This paper is concerned with machine localisation of multiple active speech sources in reverberant environments using two (binaural) microphones. Such conditions typically present a problem for ‘classical’ binaural models. Inspired by the human ability to utilise head movements, the current study...

  14. Miniature Quad-rotor Dynamics Modeling & Guidance for Vision-based Target Tracking Control Tasks

    OpenAIRE

    Barrientos Cruz, Antonio; Colorado Montaño, Julián

    2009-01-01

    This paper presents the dynamics modeling and the control & guidance architecture for specific target tracking indoors tasks using a miniature quad-rotor. Our objective is to develop a testbed using Matlab for experimentation and simulation of dynamics, control and guidance methods within a strong interplay between the hardware on board and software provisioned.

  15. The effect of dynamic workstations on the performance of various computer and office-based tasks

    NARCIS (Netherlands)

    Burford, E.M.; Botter, J.; Commissaris, D.; Könemann, R.; Hiemstra-Van Mastrigt, S.; Ellegast, R.P.

    2013-01-01

    The effect of different workstations, conventional and dynamic, on different types of performance measures for several different office and computer based task was investigated in this research paper. The two dynamic workstations assessed were the Lifespan Treadmill Desk and the RightAngle LifeBalan

  16. Combination of Adaptive Feedback Cancellation and Binaural Adaptive Filtering in Hearing Aids

    Science.gov (United States)

    Lombard, Anthony; Reindl, Klaus; Kellermann, Walter

    2009-12-01

    We study a system combining adaptive feedback cancellation and adaptive filtering connecting inputs from both ears for signal enhancement in hearing aids. For the first time, such a binaural system is analyzed in terms of system stability, convergence of the algorithms, and possible interaction effects. As major outcomes of this study, a new stability condition adapted to the considered binaural scenario is presented, some already existing and commonly used feedback cancellation performance measures for the unilateral case are adapted to the binaural case, and possible interaction effects between the algorithms are identified. For illustration purposes, a blind source separation algorithm has been chosen as an example for adaptive binaural spatial filtering. Experimental results for binaural hearing aids confirm the theoretical findings and the validity of the new measures.

  17. Combination of Adaptive Feedback Cancellation and Binaural Adaptive Filtering in Hearing Aids

    Directory of Open Access Journals (Sweden)

    Anthony Lombard

    2009-01-01

    Full Text Available We study a system combining adaptive feedback cancellation and adaptive filtering connecting inputs from both ears for signal enhancement in hearing aids. For the first time, such a binaural system is analyzed in terms of system stability, convergence of the algorithms, and possible interaction effects. As major outcomes of this study, a new stability condition adapted to the considered binaural scenario is presented, some already existing and commonly used feedback cancellation performance measures for the unilateral case are adapted to the binaural case, and possible interaction effects between the algorithms are identified. For illustration purposes, a blind source separation algorithm has been chosen as an example for adaptive binaural spatial filtering. Experimental results for binaural hearing aids confirm the theoretical findings and the validity of the new measures.

  18. Binaural integration abilities in bilateral cochlear implant user

    Institute of Scientific and Technical Information of China (English)

    Chie Obuchi; Masae Shiroma; Sayaka Ogane; Kimitaka Kaga

    2015-01-01

    Bilateral Cochlear implants (CIs) improved speech intelligibility, speech perception in background noise, and sound localization in quiet and noisy situations. However, it is unclear whether these advantages essentially result in binaural integration of acoustic stimuli from each ear. In this study, we investigated the effectiveness of binaural integration by bilateral CIs placement using binaural hearing tests and subjective auditory perceptual assessment. A 61-year-old bilateral CIs subject underwent the following four tests:the Japanese Hearing in Noise Test (HINT-J), the dichotic listening test (DLT), the Rapidly Alternating Speech Perception (RASP) test, and subjective auditory perceptual assessment. The HINT-J score was significantly higher for bilateral CIs than for a unilateral CI. However, DLT and the RASP test revealed contradictory results. Subjective auditory perceptual assessment revealed active and bright impressions for bilateral hearing, which were also noisy and strong compared with those for unilateral hearing. The results of this study revealed that bilateral CIs improved speech perception in background noise and an improved auditory impression, although the bilateral integration abilities were not improved. This was probably because the patient was required to combine information from the two ears into a single perception in DLT and the RASP test. More longitudinal data should be collected and analyzed in future studies to evaluate the long-term effects of bilateral CIs. Copyright © 2016, PLA General Hospital Department of Otolaryngology Head and Neck Surgery. Production and hosting by Elsevier (Singapore) Pte Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

  19. A Dynamic Approach of Information in a Learning Task

    Directory of Open Access Journals (Sweden)

    Sandra Begoin-Augereau

    2010-04-01

    Full Text Available A new theoretical and methodological approach of the processing of information is presented. On line modifications in the structure of information, such as stretched, broken, re- unified, or stuck pieces of information can be characterized from linguistic markers. For that two kinds of detachability from the situation are analyzed in a cognitive interpretation of Culioli's enunciative model. On one hand, the detachability linked to starting terms has for criterion the anaphora. It marks the categorization of external aggregates of information, their internalization, re-inscribing them at a subjective level, and their externalization, re-inscribing them in the spatio temporal environment. On the other hand, the detachability linked to modal terms marks a strategic reorganization of information. Both kinds of detachability are modelled by Culioli's diagram involving different levels between parameters S (subjective space and T (temporal space. The passages from one of these levels to another follow specific routes with loops and strange loops. This paper analyzes the modification of information at the highest subjective level in the verbal protocol of a 10-year- old solving the Tower of Hanoi puzzle for the first time. The generalization to other tasks and to interaction between intelligent agents results from the interactive characteristics of linguistic markers.

  20. A systematic study of binaural reproduction systems through loudspeakers

    DEFF Research Database (Denmark)

    Lacouture Parodi, Yesenia

    This Ph.D. thesis presents an investigation of the acoustical and psycho-acoustical characteristics of binaural reproduction systems through loudspeakers. The study was mainly focused on the characteristics of closely spaced loudspeakers – known as stereo-dipoles – when placed at different positi......, on pair behind and one pair above the listener. Experimental results show that a reduction of front-back confusions is obtained with the proposed system. Yet, coloration differences between loudspeaker pairs result in a degradation of the localization performance....

  1. Principles of modulation processing in monaural vs. binaural hearing

    DEFF Research Database (Denmark)

    Piechowiak, Tobias

    2005-01-01

    channels as a detection cue. Durlach [1] introduced the equalization-cancellation (EC) approach as an across-channel mechanism for explaining BMLD and it was recently used to quantitatively account for many binaural listening experiments. Buus [2] was the first to suggest that an EC-type mechanism could...... also be appropriate to account for CMR. However, it was never tested if such an approach is able to quantitatively predict CMR. The aim of the present study is to introduce an EC type model in monaural modulation processing and to test it with a certain stimulus configuration....

  2. Office task effects on comfort and body dynamics in five dynamic office chairs

    NARCIS (Netherlands)

    Groenesteijn, L.; Ellegast, R.P.; Keller, K.; Krause, F.; Berger, H.; Looze, M.P.de

    2012-01-01

    In the present study, we investigated the effect of office tasks on posture and movements in field settings, and the comfort rating for chair characteristics and correlation with type of task. The tasks studied were: computer work, telephoning, desk work and conversation. Postures, movements, chair

  3. Solar dynamic heat rejection technology. Task 1: System concept development

    Science.gov (United States)

    Gustafson, Eric; Carlson, Albert W.

    1987-01-01

    The results are presented of a concept development study of heat rejection systems for Space Station solar dynamic power systems. The heat rejection concepts are based on recent developments in high thermal transport capacity heat pipe radiators. The thermal performance and weights of each of the heat rejection subsystems is addressed in detail, and critical technologies which require development tests and evaluation for successful demonstration are assessed and identified. Baseline and several alternate heat rejection system configurations and optimum designs are developed for both Brayton and Rankine cycles. The thermal performance, mass properties, assembly requirements, reliability, maintenance requirements and life cycle cost are determined for each configuration. A specific design was then selected for each configuration which represents an optimum design for that configuration. The final recommendations of heat rejection system configuration for either the Brayton or Rankine cycles depend on the priorities established for the evaluation criteria.

  4. Better decision making in complex, dynamic tasks training with human-facilitated interactive learning environments

    CERN Document Server

    Qudrat-Ullah, Hassan

    2015-01-01

    This book describes interactive learning environments (ILEs) and their underlying concepts. It explains how ILEs can be used to improve the decision-making process and how these improvements can be empirically verified. The objective of this book is to enhance our understanding of and to gain insights into the process by which human facilitated ILEs are effectively designed and used in improving users’ decision making in complex, dynamic tasks. This book is divided into four major parts. Part I serves as an introduction to the importance and complexity of decision making in dynamic tasks. Part II provides background material, drawing upon relevant literature, for the development of an integrated process model on the effectiveness of human facilitated ILEs in improving decision making in dynamic tasks. Part III focuses on the design, development, and application of FishBankILE in laboratory experiments to gather empirical evidence for the validity of the process model. Finally, part IV presents a comprehensi...

  5. Binaural speech discrimination under noise in hearing-impaired listeners

    Science.gov (United States)

    Kumar, K. V.; Rao, A. B.

    1988-01-01

    This paper presents the results of an assessment of speech discrimination by hearing-impaired listeners (sensori-neural, conductive, and mixed groups) under binaural free-field listening in the presence of background noise. Subjects with pure-tone thresholds greater than 20 dB in 0.5, 1.0 and 2.0 kHz were presented with a version of the W-22 list of phonetically balanced words under three conditions: (1) 'quiet', with the chamber noise below 28 dB and speech at 60 dB; (2) at a constant S/N ratio of +10 dB, and with a background white noise at 70 dB; and (3) same as condition (2), but with the background noise at 80 dB. The mean speech discrimination scores decreased significantly with noise in all groups. However, the decrease in binaural speech discrimination scores with an increase in hearing impairment was less for material presented under the noise conditions than for the material presented in quiet.

  6. Binaural cues provide for a release from informational masking.

    Science.gov (United States)

    Tolnai, Sandra; Dolležal, Lena-Vanessa; Klump, Georg M

    2015-10-01

    Informational masking (IM) describes the insensitivity of detecting a change in sound features in a complex acoustical environment when such a change could easily be detected in the absence of distracting sounds. IM occurs because of the similarity between deviant sound and distracting sounds (so-called similarity-based IM) and/or stimulus uncertainty stemming from trial-to-trial variability (so-called uncertainty-based IM). IM can be abolished if similarity-based or uncertainty-based IM are minimized. Here, we modulated similarity-based IM using binaural cues. Standard/deviant tones and distracting tones were presented sequentially, and level-increment thresholds were measured. Deviant tones differed from standard tones by a higher sound level. Distracting tones covered a wide range of levels. Standard/deviant tones and distracting tones were characterized by their interaural time difference (ITD), interaural level difference (ILD), or both ITD and ILD. The larger the ITD or ILD was, the better similarity-based IM was overcome. If both interaural differences were applied to standard/deviant tones, the release from IM was larger than when either interaural difference was used. The results show that binaural cues are potent cues to abolish similarity-based IM and that the auditory system makes use of multiple available cues. PMID:26413722

  7. Binaural release from masking with single- and multi-electrode stimulation in children with cochlear implants.

    Science.gov (United States)

    Todd, Ann E; Goupell, Matthew J; Litovsky, Ruth Y

    2016-07-01

    Cochlear implants (CIs) provide children with access to speech information from a young age. Despite bilateral cochlear implantation becoming common, use of spatial cues in free field is smaller than in normal-hearing children. Clinically fit CIs are not synchronized across the ears; thus binaural experiments must utilize research processors that can control binaural cues with precision. Research to date has used single pairs of electrodes, which is insufficient for representing speech. Little is known about how children with bilateral CIs process binaural information with multi-electrode stimulation. Toward the goal of improving binaural unmasking of speech, this study evaluated binaural unmasking with multi- and single-electrode stimulation. Results showed that performance with multi-electrode stimulation was similar to the best performance with single-electrode stimulation. This was similar to the pattern of performance shown by normal-hearing adults when presented an acoustic CI simulation. Diotic and dichotic signal detection thresholds of the children with CIs were similar to those of normal-hearing children listening to a CI simulation. The magnitude of binaural unmasking was not related to whether the children with CIs had good interaural time difference sensitivity. Results support the potential for benefits from binaural hearing and speech unmasking in children with bilateral CIs. PMID:27475132

  8. Age-Related Shifts in Brain Activity Dynamics during Task Switching

    OpenAIRE

    Jimura, Koji; Braver, Todd S.

    2009-01-01

    Cognitive aging studies have suggested that older adults show declines in both sustained and transient cognitive control processes. However, previous neuroimaging studies have primarily focused on age-related change in the magnitude, but not temporal dynamics, of brain activity. The present study compared brain activity dynamics in healthy old and young adults during task switching. A mixed blocked/event-related functional magnetic resonance imaging design enabled separation of transient and ...

  9. The window of my eyes: Task disengagement and mental fatigue covary with pupil dynamics.

    Science.gov (United States)

    Hopstaken, Jesper F; van der Linden, Dimitri; Bakker, Arnold B; Kompier, Michiel A J

    2015-09-01

    Although mental fatigue is a complex, multi-facetted state that involves changes in motivation, cognition, and mood, one of its main characteristics is reduced task engagement. Despite its relevance for performance and safety, knowledge about the underlying neurocognitive processes in mental fatigue is still limited. Inspired by the idea that central norepinephrine plays an important role in regulating task engagement, we test a set of predictions that have been derived from recent studies that relate pupil dynamics to the levels of norepinephrine in the brain. Participants worked on a 2-back task for 2h while we used pupil measures to further explore the link between task engagement and the effects of mental fatigue. We hypothesized that baseline pupil diameter and stimulus-evoked pupil dilations decrease with increasing fatigue. Also, because previous studies have shown that the effects of fatigue are reversible by increasing the task rewards, we hypothesized that increasing the task rewards after 2h on the task would restore these pupil measures to pre-fatigue levels. While we did not find a decrease in baseline pupil diameter, we found that increasing mental fatigue coincided with diminished stimulus-evoked pupil dilation. Also, we confirmed that when sufficient rewards were presented to a fatigued individual, the pupil dilations could be restored. This supports the view that motivational factors are important in predicting engagement versus disengagement during fatigue. PMID:26196899

  10. Detection and identification of monaural and binaural pitch contours in dyslexic listeners

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten; Poelmans, Hanne;

    2010-01-01

    Binaural pitch stimuli were used in several recent studies to test for the presence of binaural auditory impairment in reading-disabled subjects. The outcome of three of these studies (Dougherty et al., 1998; Edwards et al., 2004; Chait et al., 2007) has been contradictory: Where the former two...... found that a majority of dyslexic subjects were unable to hear binaural pitch, the latter obtained a clear response of dyslexic listeners to Huggins’ pitch (HP) (Cramer and Huggins, 1958). The present study clarified whether impaired binaural pitch perception is found in dyslexia. Results from a pitch...... and probably reflects impaired cognitive mechanisms related to auditory memory or auditory attention rather than impaired low-level auditory processing per se....

  11. Binaural technology for e.g. rendering auditory virtual environments

    DEFF Research Database (Denmark)

    Hammershøi, Dorte

    2008-01-01

    Jens Blauert's research up through the late 60ties and later, pioneered the field of binaural technology and auditory virtual environments. He mastered the measurement of head-related transfer functions (HRTFs) before the term was introduced, and his methods were standard for decades. While most......, helped mediate the understanding that if the transfer functions could be mastered, then important dimensions of the auditory percept could also be controlled. He early understood the potential of using the HRTFs and numerical sound transmission analysis programs for rendering auditory virtual...... environments. Jens Blauert participated in many European cooperation projects exploring  this field (and others), among other the SCATIS project addressing the auditory-tactile dimensions in the absence of visual information....

  12. Age-related shifts in brain activity dynamics during task switching.

    Science.gov (United States)

    Jimura, Koji; Braver, Todd S

    2010-06-01

    Cognitive aging studies have suggested that older adults show declines in both sustained and transient cognitive control processes. However, previous neuroimaging studies have primarily focused on age-related change in the magnitude, but not temporal dynamics, of brain activity. The present study compared brain activity dynamics in healthy old and young adults during task switching. A mixed blocked/event-related functional magnetic resonance imaging design enabled separation of transient and sustained neural activity associated with cognitive control. Relative to young adults, older adults exhibited not only decreased sustained activity in the anterior prefrontal cortex (aPFC) during task-switching blocks but also increased transient activity on task-switch trials. Another pattern of age-related shift in dynamics was present in the lateral PFC (lPFC) and posterior parietal cortex (PPC), with younger adults showing a cue-related response during task-switch trials in lPFC and PPC, whereas older adults exhibited switch-related activation during the cue period in PPC only. In all 3 regions, these qualitatively distinct patterns of brain activity predicted qualitatively distinct patterns of behavioral performance across the 2 age groups. Together, these results suggest that older adults may shift from a proactive to reactive cognitive control strategy as a means of retaining relatively preserved behavioral performance in the face of age-related neurocognitive changes. PMID:19805420

  13. Binaural advantages in users of bimodal and bilateral cochlear implant devices

    OpenAIRE

    Kokkinakis, Kostas; Pak, Natalie

    2013-01-01

    This paper investigates to what extent users of bilateral and bimodal fittings should expect to benefit from all three different binaural advantages found to be present in normal-hearing listeners. Head-shadow and binaural squelch are advantages occurring under spatially separated speech and noise, while summation emerges when speech and noise coincide in space. For 14 bilateral or bimodal listeners, speech reception thresholds in the presence of four-talker babble were measured in sound-fiel...

  14. Advantages of Binaural Amplification to Acceptable Noise Level of Directional Hearing Aid Users

    OpenAIRE

    Kim, Ja-Hee; Lee, Jae Hee; Lee, Ho-Ki

    2014-01-01

    Objectives The goal of the present study was to examine whether Acceptable Noise Levels (ANLs) would be lower (greater acceptance of noise) in binaural listening than in monaural listening condition and also whether meaningfulness of background speech noise would affect ANLs for directional microphone hearing aid users. In addition, any relationships between the individual binaural benefits on ANLs and the individuals' demographic information were investigated. Methods Fourteen hearing aid us...

  15. Binaural Unmasking of Multi-channel Stimuli in Bilateral Cochlear Implant Users

    OpenAIRE

    Van Deun, Lieselot; Van Wieringen, Astrid; Francart, Tom; Büchner, Andreas; Lenarz, Thomas; Wouters, Jan

    2011-01-01

    Previous work suggests that bilateral cochlear implant users are sensitive to interaural cues if experimental speech processors are used to preserve accurate interaural information in the electrical stimulation pattern. Binaural unmasking occurs in adults and children when an interaural delay is applied to the envelope of a high-rate pulse train. Nevertheless, for speech perception, binaural unmasking benefits have not been demonstrated consistently, even with coordinated stimulation at both ...

  16. Dynamic trajectory of multiple single-unit activity during working memory task in rats

    Directory of Open Access Journals (Sweden)

    Xiaofan eZhang

    2015-09-01

    Full Text Available Working memory plays an important role in complex cognitive tasks. A popular theoretical view is that attracting properties of neuronal dynamics underlie cognitive processing. The question raised here as to how the attracting dynamics evolve in working memory. To address this issue, we investigated the multiple single-unit activity dynamics in rat medial prefrontal cortex (mPFC during a Y-maze working memory task. The approach worked by reconstructing state space from delays of the original single-unit firing rate variables, which were further analyzed using kernel principal component analysis (KPCA. Then the neural trajectories were obtained to visualize the multi¬ple single-unit activity. Furthermore, the maximal Lyapunov exponent (MLE was calculated to quantitatively evaluate the neural trajectories during the working memory task. The results showed that the neuronal activity produced stable and reproducible neural trajectories in the correct trials while showed irregular trajectories in the incorrect trials, which may establish a link between the neurocognitive process and behavioral performance in working memory. The MLEs significantly increased during working memory in the correctly performed trials, indicating an increased divergence of the neural trajectories. In the incorrect trials, the MLEs were nearly 0 and remained unchanged during the task. Taken together, the trial-specific neural trajectory provides an effective way to track the instantaneous state of the neuronal ensemble during the working memory task and offers valuable insights into working memory function. The MLE describes the changes of neural dynamics in working memory and may reflect different neuronal ensemble states in working memory.

  17. Multiple Computing Task Scheduling Method Based on Dynamic Data Replication and Hierarchical Strategy

    Directory of Open Access Journals (Sweden)

    Xiang Zhou

    2014-02-01

    Full Text Available As for the problem of how to carry out task scheduling and data replication effectively in the grid and to reduce task’s execution time, this thesis proposes the task scheduling algorithm and the optimum dynamic data replication algorithm and builds a scheme to effectively combine these two algorithms. First of all, the scheme adopts the ISS algorithm considering the number of tasks waiting queue, the location of task demand data and calculation capacity of site by adopting the method of network structure’s hierarchical scheduling to calculate the cost of comprehensive task with the proper weight efficiency and search out the best compute node area. And then the algorithm of ODHRA is adopted to analyze the data transmission time, memory access latency, waiting copy requests in the queue and the distance between nodes, choose out the best replications location in many copies combined with copy placement and copy management to reduce the file access time. The simulation results show that the proposed scheme compared with other algorithm has better performance in terms of average task execution time. 

  18. Internal representation of task rules by recurrent dynamics: the importance of the diversity of neural responses

    Directory of Open Access Journals (Sweden)

    Mattia Rigotti

    2010-10-01

    Full Text Available Neural activity of behaving animals, especially in the prefrontal cortex, is highly heterogeneous, with selective responses to diverse aspects of the executed task. We propose a general model of recurrent neural networks that perform complex rule-based tasks, and we show that the diversity of neuronal responses plays a fundamental role when the behavioral responses are context dependent. Specifically, we found that when the inner mental states encoding the task rules are represented by stable patterns of neural activity (attractors of the neural dynamics, the neurons must be selective for combinations of sensory stimuli and inner mental states. Such mixed selectivity is easily obtained by neurons that connect with random synaptic strengths both to the recurrent network and to neurons encoding sensory inputs. The number of randomly connected neurons needed to solve a task is on average only three times as large as the number of neurons needed in a network designed ad hoc. Moreover, the number of needed neurons grows only linearly with the number of task-relevant events and mental states, provided that each neuron responds to a large proportion of events (dense/distributed coding. A biologically realistic implementation of the model captures several aspects of the activity recorded from monkeys performing context dependent tasks. Our findings explain the importance of the diversity of neural responses and provide us with simple and general principles for designing attractor neural networks that perform complex computation.

  19. Evaluation of static and dynamic perfusion cardiac computed tomography for quantitation and classification tasks.

    Science.gov (United States)

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R; La Riviere, Patrick J; Alessio, Adam M

    2016-04-01

    Cardiac computed tomography (CT) acquisitions for perfusion assessment can be performed in a dynamic or static mode. Either method may be used for a variety of clinical tasks, including (1) stratifying patients into categories of ischemia and (2) using a quantitative myocardial blood flow (MBF) estimate to evaluate disease severity. In this simulation study, we compare method performance on these classification and quantification tasks for matched radiation dose levels and for different flow states, patient sizes, and injected contrast levels. Under conditions simulated, the dynamic method has low bias in MBF estimates (0 to [Formula: see text]) compared to linearly interpreted static assessment (0.45 to [Formula: see text]), making it more suitable for quantitative estimation. At matched radiation dose levels, receiver operating characteristic analysis demonstrated that the static method, with its high bias but generally lower variance, had superior performance ([Formula: see text]) in stratifying patients, especially for larger patients and lower contrast doses [area under the curve [Formula: see text] to 96 versus 0.86]. We also demonstrate that static assessment with a correctly tuned exponential relationship between the apparent CT number and MBF has superior quantification performance to static assessment with a linear relationship and to dynamic assessment. However, tuning the exponential relationship to the patient and scan characteristics will likely prove challenging. This study demonstrates that the selection and optimization of static or dynamic acquisition modes should depend on the specific clinical task.

  20. Binaural Fusion and Listening Effort in Children Who Use Bilateral Cochlear Implants: A Psychoacoustic and Pupillometric Study

    OpenAIRE

    Steel, Morrison M.; Papsin, Blake C.; Karen A Gordon

    2015-01-01

    Bilateral cochlear implants aim to provide hearing to both ears for children who are deaf and promote binaural/spatial hearing. Benefits are limited by mismatched devices and unilaterally-driven development which could compromise the normal integration of left and right ear input. We thus asked whether children hear a fused image (ie. 1 vs 2 sounds) from their bilateral implants and if this "binaural fusion" reduces listening effort. Binaural fusion was assessed by asking 25 deaf children wit...

  1. Effects of automobile steering characteristics on driver vehicle system dynamics in regulation tasks

    Science.gov (United States)

    Mcruer, D. T.; Klein, R.

    1975-01-01

    A regulation task which subjected the automobile to a random gust disturbance which is countered by driver control action is used to study the effects of various automobile steering characteristics on the driver/vehicle system. The experiments used a variable stability automobile specially configured to permit insertion of the simulated gust disturbance and the measurement of the driver/vehicle system characteristics. Driver/vehicle system dynamics were measured and interpreted as an effective open loop system describing function. Objective measures of system bandwidth, stability, and time delays were deduced and compared. These objective measures were supplemented by driver ratings. A tentative optimum range of vehicle dynamics for the directional regulation task was established.

  2. The tuning of human motor response to risk in a dynamic environment task.

    Directory of Open Access Journals (Sweden)

    Amber Dunning

    Full Text Available The role of motor uncertainty in discrete or static space tasks, such as pointing tasks, has been investigated in many experiments. These studies have shown that humans hold an internal representation of intrinsic and extrinsic motor uncertainty and compensate for this variability when planning movement. The aim of this study was to investigate how humans respond to uncertainties during movement execution in a dynamic environment despite indeterminate knowledge of the outcome of actions. Additionally, the role of errors, or lack thereof, in predicting risk was examined. In the experiment, subjects completed a driving simulation game on a two-lane road. The road contained random curves so that subjects were forced to use sensory feedback to complete the task and could not rely only on motor planning. Risk was manipulated by using horizontal perturbations to create the illusion of driving on a bumpy road, thereby imposing motor uncertainty, and altering the cost function of the road. Results suggest continual responsiveness to cost and uncertainty in a dynamic task and provide evidence that subjects avoid risk even in the absence of errors. The results suggest that humans tune their statistical motor behavior based on cost, taking into account probabilities of possible outcomes in response to environmental uncertainty.

  3. Dynamic Task Allocation in Multi-Hop Multimedia Wireless Sensor Networks with Low Mobility

    Directory of Open Access Journals (Sweden)

    Klaus Moessner

    2013-10-01

    Full Text Available This paper presents a task allocation-oriented framework to enable efficient in-network processing and cost-effective multi-hop resource sharing for dynamic multi-hop multimedia wireless sensor networks with low node mobility, e.g., pedestrian speeds. The proposed system incorporates a fast task reallocation algorithm to quickly recover from possible network service disruptions, such as node or link failures. An evolutional self-learning mechanism based on a genetic algorithm continuously adapts the system parameters in order to meet the desired application delay requirements, while also achieving a sufficiently long network lifetime. Since the algorithm runtime incurs considerable time delay while updating task assignments, we introduce an adaptive window size to limit the delay periods and ensure an up-to-date solution based on node mobility patterns and device processing capabilities. To the best of our knowledge, this is the first study that yields multi-objective task allocation in a mobile multi-hop wireless environment under dynamic conditions. Simulations are performed in various settings, and the results show considerable performance improvement in extending network lifetime compared to heuristic mechanisms. Furthermore, the proposed framework provides noticeable reduction in the frequency of missing application deadlines.

  4. Multi-Satellite Scheduling Approach for Dynamic Areal Tasks Triggered by Emergent Disasters

    Science.gov (United States)

    Niu, X. N.; Zhai, X. J.; Tang, H.; Wu, L. X.

    2016-06-01

    The process of satellite mission scheduling, which plays a significant role in rapid response to emergent disasters, e.g. earthquake, is used to allocate the observation resources and execution time to a series of imaging tasks by maximizing one or more objectives while satisfying certain given constraints. In practice, the information obtained of disaster situation changes dynamically, which accordingly leads to the dynamic imaging requirement of users. We propose a satellite scheduling model to address dynamic imaging tasks triggered by emergent disasters. The goal of proposed model is to meet the emergency response requirements so as to make an imaging plan to acquire rapid and effective information of affected area. In the model, the reward of the schedule is maximized. To solve the model, we firstly present a dynamic segmenting algorithm to partition area targets. Then the dynamic heuristic algorithm embedding in a greedy criterion is designed to obtain the optimal solution. To evaluate the model, we conduct experimental simulations in the scene of Wenchuan Earthquake. The results show that the simulated imaging plan can schedule satellites to observe a wider scope of target area. We conclude that our satellite scheduling model can optimize the usage of satellite resources so as to obtain images in disaster response in a more timely and efficient manner.

  5. Static and dynamic posterior cingulate cortex nodal topology of default mode network predicts attention task performance.

    Science.gov (United States)

    Lin, Pan; Yang, Yong; Jovicich, Jorge; De Pisapia, Nicola; Wang, Xiang; Zuo, Chun S; Levitt, James Jonathan

    2016-03-01

    Characterization of the default mode network (DMN) as a complex network of functionally interacting dynamic systems has received great interest for the study of DMN neural mechanisms. In particular, understanding the relationship of intrinsic resting-state DMN brain network with cognitive behaviors is an important issue in healthy cognition and mental disorders. However, it is still unclear how DMN functional connectivity links to cognitive behaviors during resting-state. In this study, we hypothesize that static and dynamic DMN nodal topology is associated with upcoming cognitive task performance. We used graph theory analysis in order to understand better the relationship between the DMN functional connectivity and cognitive behavior during resting-state and task performance. Nodal degree of the DMN was calculated as a metric of network topology. We found that the static and dynamic posterior cingulate cortex (PCC) nodal degree within the DMN was associated with task performance (Reaction Time). Our results show that the core node PCC nodal degree within the DMN was significantly correlated with reaction time, which suggests that the PCC plays a key role in supporting cognitive function. PMID:25904156

  6. Task 7a: Dynamic analysis of Paks NPP structures reactor building

    International Nuclear Information System (INIS)

    This report describes dynamic response calculation of the NPP Paks, reactor building to the full scale blast testing. All calculations described in this report have been elaborated within the scope of IAEA co-ordinated research - Benchmark Study for for seismic analysis/testing of NPPs type WWER - Task 7a - Dynamic Analysis of PAKS NPP structures, i.e. reactor building. The input in the form of time history of velocities or accelerations on the free field caused by blast testing was only available for the participants of the task No.7a. The aim of this task is to calculate the dynamic response to the blast load in the form of floor response spectra in selected nodes of the structure without knowing the measured data. The data measured by the full scale blast test are published and the results of different calculations compared. The following structures were taken into account: turbine hall, intermediate multi-storey building, lateral multi-storey building, reactor building, ventilation center and condenser towers

  7. Performance comparison between static and dynamic cardiac CT on perfusion quantitation and patient classification tasks

    Science.gov (United States)

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R.; La Riviere, Patrick J.; Alessio, Adam M.

    2015-03-01

    Cardiac CT acquisitions for perfusion assessment can be performed in a dynamic or static mode. In this simulation study, we evaluate the relative classification and quantification performance of these modes for assessing myocardial blood flow (MBF). In the dynamic method, a series of low dose cardiac CT acquisitions yields data on contrast bolus dynamics over time; these data are fit with a model to give a quantitative MBF estimate. In the static method, a single CT acquisition is obtained, and the relative CT numbers in the myocardium are used to infer perfusion states. The static method does not directly yield a quantitative estimate of MBF, but these estimates can be roughly approximated by introducing assumed linear relationships between CT number and MBF, consistent with the ways such images are typically visually interpreted. Data obtained by either method may be used for a variety of clinical tasks, including 1) stratifying patients into differing categories of ischemia and 2) using the quantitative MBF estimate directly to evaluate ischemic disease severity. Through simulations, we evaluate the performance on each of these tasks. The dynamic method has very low bias in MBF estimates, making it particularly suitable for quantitative estimation. At matched radiation dose levels, ROC analysis demonstrated that the static method, with its high bias but generally lower variance, has superior performance in stratifying patients, especially for larger patients.

  8. Subjective diffuseness of music signals convolved with binaural impulse responses

    Science.gov (United States)

    Shimokura, Ryota; Tronchin, Lamberto; Cocchi, Alessandro; Soeta, Yoshiharu

    2011-07-01

    The spatial impression of sound in a hall can be quantified using sound field factors such as the interaural cross-correlation coefficient (IACC) calculated from binaural impulse response (BIR), henceforth denoted by IACC IR. The subjective diffuseness for the listener is a spatial attribute which depends on factors associated both with the source signal and with the actual sound field, and is quantified using the IACC of the signal received by the listener, henceforth denoted by IACC SR. Therefore, the subjective diffuseness in a given hall may change with the music. The aims of this study are to estimate the IACC SR from the IACC IR and the factors, which is obtained from autocorrelation function (ACF) of music signal, and to evaluate the subjective diffuseness by these factors. First, the relationship between the IACC IR and IACC SR was investigated. Second, subjective diffuseness was measured by a psycho-acoustical experiment. As a result, the IACC SR could be estimated from the IACC IR of the BIR and the effective duration ( τe) from the ACF of music signal. It was found that the effects of BIRs on subjective diffuseness could be evaluated by IACC IR for almost all subjects, while the effects of music signals could be evaluated by the τe and the width of the peak at τ=0 ( Wϕ(0) ) of the ACF.

  9. Directional hearing aid using hybrid adaptive beamformer (HAB) and binaural ITE array

    Science.gov (United States)

    Shaw, Scott T.; Larow, Andy J.; Gibian, Gary L.; Sherlock, Laguinn P.; Schulein, Robert

    2002-05-01

    A directional hearing aid algorithm called the Hybrid Adaptive Beamformer (HAB), developed for NIH/NIA, can be applied to many different microphone array configurations. In this project the HAB algorithm was applied to a new array employing in-the-ear microphones at each ear (HAB-ITE), to see if previous HAB performance could be achieved with a more cosmetically acceptable package. With diotic output, the average benefit in threshold SNR was 10.9 dB for three HoH and 11.7 dB for five normal-hearing subjects. These results are slightly better than previous results of equivalent tests with a 3-in. array. With an innovative binaural fitting, a small benefit beyond that provided by diotic adaptive beamforming was observed: 12.5 dB for HoH and 13.3 dB for normal-hearing subjects, a 1.6 dB improvement over the diotic presentation. Subjectively, the binaural fitting preserved binaural hearing abilities, giving the user a sense of space, and providing left-right localization. Thus the goal of creating an adaptive beamformer that simultaneously provides excellent noise reduction and binaural hearing was achieved. Further work remains before the HAB-ITE can be incorporated into a real product, optimizing binaural adaptive beamforming, and integrating the concept with other technologies to produce a viable product prototype. [Work supported by NIH/NIDCD.

  10. Capturing blocked-entrance binaural signals from open-entrance recordings

    DEFF Research Database (Denmark)

    Hammershøi, Dorte; Hoffmann, Pablo F.; Olesen, Søren Krarup;

    2008-01-01

    Binaural recordings enable us to capture all sound attributes including spatial information, room effect, and source characteristics in a given environment. It has been shown that blocked-entrance binaural recordings provide advantages over open-entrance recordings, primarily because the blocked-...... context. To this purpose, equalization filters are derived from the ratio between blocked and open ear canal transfer functions. Different transfer-function measuring techniques and inverse filtering methods are evaluated.......Binaural recordings enable us to capture all sound attributes including spatial information, room effect, and source characteristics in a given environment. It has been shown that blocked-entrance binaural recordings provide advantages over open-entrance recordings, primarily because the blocked......-entrance recordings is not influenced by the ear canal acoustics of the individual for which it is recorded. However, blocking the ear canal for recoding imposes an obvious disruption to normal hearing conditions, which may be unacceptable for applications in which binaural audio capturing is desired but without...

  11. 一种基于PVM的主动的任务动态调度策略%A PVM-Based Active Dynamic Task Scheduling Strategy

    Institute of Scientific and Technical Information of China (English)

    朱世进; 李毅; 周明天; 王月

    2000-01-01

    This paper introduces a new PVM-based active dynamic task schcduling strategy. This strategy makes node machine to play an active role in task scheduling. In this way,task scheduling can take full account of loading of node machine and distribute tasks according to this strategy. So we can fulfill load balancing for system and avoid extra burden due to task migration.

  12. Dynamic Scheduling of Skippable Periodic Tasks With Energy Efficiency In Weakly Hard Real-Time System

    Directory of Open Access Journals (Sweden)

    Santhi Baskaran

    2010-12-01

    Full Text Available Energy consumption is a critical design issue in real-time systems, especially in battery- operated systems. Maintaining high performance, while extending the battery life between charges is an interesting challenge for system designers. Dynamic Voltage Scaling (DVS allows a processor to dynamically change speed and voltage at run time, thereby saving energy by spreading run cycles into idle time.Knowing when to use full power and when not, requires the cooperation of the operating system scheduler. Usually, higher processor voltage and frequency leads to higher system throughput whileenergy reduction can be obtained using lower voltage and frequency. Instead of lowering processorvoltage and frequency as much as possible, energy efficient real-time scheduling adjusts voltage andfrequency according to some optimization criteria, such as low energy consumption or high throughput,while it meets the timing constraints of the real-time tasks. As the quantity and functional complexity ofbattery powered portable devices continues to raise, energy efficient design of such devices has becomeincreasingly important. Many real-time scheduling algorithms have been developed recently to reduceenergy consumption in the portable devices that use DVS capable processors. Extensive power awarescheduling techniques have been published for energy reduction, but most of them have been focusedsolely on reducing the processor energy consumption. While the processor is one of the major powerhungry units in the system, other peripherals such as network interface card, memory banks, disks alsoconsume significant amount of power. Dynamic Power Down (DPD technique is used to reduce energyconsumption by shutting down the processing unit and peripheral devices, when the system is idle. Threealgorithms namely Red Tasks Only (RTO, Blue When Possible (BWP and Red as Late as Possible (RLPare proposed in the literature to schedule the real-time tasks in Weakly-hard real

  13. Selecting a Dynamic Simulation Modeling Method for Health Care Delivery Research—Part 2: Report of the ISPOR Dynamic Simulation Modeling Emerging Good Practices Task Force

    NARCIS (Netherlands)

    Marshall, Deborah A.; Burgos-Liz, Lina; IJzerman, M.J.; Crown, William; Padula, William V.; Wong, Peter K.; Pasupathy, Kalyan S.; Higashi, Mitchell K.; Osgood, Nathaniel D.

    2015-01-01

    In a previous report, the ISPOR Task Force on Dynamic Simulation Modeling Applications in Health Care Delivery Research Emerging Good Practices introduced the fundamentals of dynamic simulation modeling and identified the types of health care delivery problems for which dynamic simulation modeling c

  14. Numerical simulation of gas dynamics and heat exchange tasks in fuel assemblies of the nuclear reactors

    International Nuclear Information System (INIS)

    This report presents a PC-based program for solution gas dynamics and heat exchange mathematical tasks in fuel assemblies of the fast-neutron nuclear reactors. A fuel assembly consisting of bulk heat-generating elements, which are integrated together by the system of supply and pressure manifolds, is examined. Spherical heat-generating microelements, which contain nuclear fuel, are pulled into the heat-generating elements. Gaseous coolant proceed from supply manifolds to heat-generating elements, where it withdraws the nuclear reaction heat and assembles in pressure manifolds

  15. Sensory modality-specific spatio-temporal dynamics in response to counting tasks.

    Science.gov (United States)

    Gohel, Bakul; Jeong, Yong

    2014-10-01

    From perception to behavior, the human brain processes information in a flexible and abstract manner independent of an input sensory modality. However, the mechanism of such multisensory neural information processing in the brain remains under debate. Relatedly, studies often aim to investigate whether certain brain regions behave in a modality-specific manner or invariantly. Previous studies regarding multisensory information processing have commonly reported only on the activation of brain regions in response to unimodal or multimodal sensory stimuli. However, less attention has been given to the modality effect on the dynamics of such regions, which could advance our understanding of neuronal information processing. In this study, we investigated whether brain regions show modality-specific or invariant high-temporal dynamics. Electrocardiogram (EEG) was recorded from healthy, normal subjects during beep-, flash- and click-counting tasks, which corresponded to auditory, visual and tactile modalities, respectively. EEG dynamics regarding event-related spectral perturbations (ERSP) in ICA time-series data were compared across the sensory modalities using a multivariate pattern analysis. We found modality-specific EEG dynamics in the prefrontal cortex, whereas we found modality-specific and cross-modal dynamics in the early visual cortex.

  16. Rate-constrained source separation for speech enhancement in wireless-communicated binaural hearing aids

    Science.gov (United States)

    Ayllón, David; Gil-Pita, Roberto; Rosa-Zurera, Manuel

    2013-12-01

    A recent trend in hearing aids is the connection of the left and right devices to collaborate between them. Binaural systems can provide natural binaural hearing and support the improvement of speech intelligibility in noise, but they require data transmission between both devices, which increases the power consumption. This paper presents a novel sound source separation algorithm for binaural speech enhancement based on supervised machine learning and time-frequency masking. The system is designed considering the power restrictions in hearing aids, constraining both the computational cost of the algorithm and the transmission bit rate. The transmission schema is optimized using a tailored evolutionary algorithm that assigns a different number of bits to each frequency band. The proposed algorithm requires less than 10% of the available computational resources for signal processing and obtains good separation performance using bit rates lower than 64 kbps.

  17. Binaurality and azimuth tun-ing of neurons in the auditorycortex of the big brown bat

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By using a combined closed and free-field stimulation system, binaurality and azimuth tuning of the neurons in the auditory cortex of the big brown bat, Eptesicus fuscus, were studied. A variety of azimuth-tuning functions were demonstrated for the binaural neurons. The large majority of EE (contralateral and ipsilateral excitatory) neurons exhibited azimuth selectivity with the best azimuths (BA) at contralateral 30(- 40(, some at ipsilateral 20(-40( and preferred azimuth ranges (PAR, response amplitude ≥75% of maximum) between 8( and 40(. Sound source azimuths strongly modulate spike counts with a mean modulation depth of 83.8% for EE neurons. EI (contralateral excitatory and ipsilateral inhibitory) neurons have simple azimuth tuning with BA located at contralateral 20(-40( and a broad PAR ranged from 30( to 55(. The present results suggest that azimuth-tuning characteristics of binaural neurons in the auditory cortex of the bat are of significance for acoustic behaviour.

  18. Dynamic Scheduling of Skippable Periodic Tasks with Energy Efficiency in Weakly Hard Real-Time System

    CERN Document Server

    Baskaran, Santhi

    2010-01-01

    Energy consumption is a critical design issue in real-time systems, especially in battery- operated systems. Maintaining high performance, while extending the battery life between charges is an interesting challenge for system designers. Dynamic Voltage Scaling (DVS) allows a processor to dynamically change speed and voltage at run time, thereby saving energy by spreading run cycles into idle time. Knowing when to use full power and when not, requires the cooperation of the operating system scheduler. Usually, higher processor voltage and frequency leads to higher system throughput while energy reduction can be obtained using lower voltage and frequency. Instead of lowering processor voltage and frequency as much as possible, energy efficient real-time scheduling adjusts voltage and frequency according to some optimization criteria, such as low energy consumption or high throughput, while it meets the timing constraints of the real-time tasks. As the quantity and functional complexity of battery powered porta...

  19. Identifying the processes underpinning anticipation and decision-making in a dynamic time-constrained task.

    Science.gov (United States)

    Roca, André; Ford, Paul R; McRobert, Allistair P; Mark Williams, A

    2011-08-01

    A novel, representative task was used to examine skill-based differences in the perceptual and cognitive processes underlying performance on a dynamic, externally paced task. Skilled and less skilled soccer players were required to move and interact with life-size, action sequences involving 11 versus 11 soccer situations filmed from the perspective of a central defender in soccer. The ability of participants to anticipate the intentions of their opponents and to make decisions about how they should respond was measured across two separate experiments. In Experiment 1, visual search behaviors were examined using an eye-movement registration system. In Experiment 2, retrospective verbal reports of thinking were gathered from a new sample of skilled and less skilled participants. Skilled participants were more accurate than less skilled participants at anticipating the intentions of opponents and in deciding on an appropriate course of action. The skilled players employed a search strategy involving more fixations of shorter duration in a different sequential order and toward more disparate and informative locations in the display when compared with the less skilled counterparts. The skilled players generated a greater number of verbal report statements with a higher proportion of evaluation, prediction, and planning statements than the less skilled players, suggesting they employed more complex domain-specific memory representations to solve the task. Theoretical, methodological, and practical implications are discussed. PMID:21305386

  20. Dynamic and task-dependent encoding of speech and voice by phase reorganization of cortical oscillations.

    Science.gov (United States)

    Bonte, Milene; Valente, Giancarlo; Formisano, Elia

    2009-02-11

    Speech and vocal sounds are at the core of human communication. Cortical processing of these sounds critically depends on behavioral demands. However, the neurocomputational mechanisms enabling this adaptive processing remain elusive. Here we examine the task-dependent reorganization of electroencephalographic responses to natural speech sounds (vowels /a/, /i/, /u/) spoken by three speakers (two female, one male) while listeners perform a one-back task on either vowel or speaker identity. We show that dynamic changes of sound-evoked responses and phase patterns of cortical oscillations in the alpha band (8-12 Hz) closely reflect the abstraction and analysis of the sounds along the task-relevant dimension. Vowel categorization leads to a significant temporal realignment of responses to the same vowel, e.g., /a/, independent of who pronounced this vowel, whereas speaker categorization leads to a significant temporal realignment of responses to the same speaker, e.g., speaker 1, independent of which vowel she/he pronounced. This transient and goal-dependent realignment of neuronal responses to physically different external events provides a robust cortical coding mechanism for forming and processing abstract representations of auditory (speech) input. PMID:19211877

  1. Dynamic cognitive control of irrelevant sound: Increased task engagement attenuates semantic auditory distraction.

    Science.gov (United States)

    Marsh, John E; Sörqvist, Patrik; Hughes, Robert W

    2015-10-01

    Two experiments investigated reactive top-down cognitive control of the detrimental influence of spoken distractors semantically related to words presented visually for free recall. Experiment 1 demonstrated that an increase in focal-task engagement-promoted experimentally by reducing the perceptual discriminability of the visual target words-eliminated the disruption by such distractors of veridical recall and also attenuated the erroneous recall of the distractors. A recall instruction that eliminates the requirement for output monitoring was used in Experiment 2 to investigate whether increased task engagement shields against distraction through a change in output-monitoring processes (back-end control) or by affecting the processing of the distractors during their presentation (front-end control). Rates of erroneous distractor recall were much greater than in Experiment 1, but both erroneous distractor recall and the disruptive effect of distractors on veridical recall were still attenuated under reduced target-word discriminability. Taken together, the results show that task engagement is under dynamic strategic control and can be modulated to shield against auditory distraction by attenuating distractor processing at encoding, thereby preventing distractors from coming to mind at test. (PsycINFO Database Record

  2. Evaluation of linearly solvable Markov decision process with dynamic model learning in a mobile robot navigation task

    Directory of Open Access Journals (Sweden)

    Ken eKinjo

    2013-04-01

    Full Text Available Linearly solvable Markov Decision Process (LMDP is a class of optimal control problem in whichthe Bellman’s equation can be converted into a linear equation by an exponential transformation ofthe state value function (Todorov, 2009. In an LMDP, the optimal value function and the correspondingcontrol policy are obtained by solving an eigenvalue problem in a discrete state space or an eigenfunctionproblem in a continuous state using the knowledge of the system dynamics and the action, state, andterminal cost functions.In this study, we evaluate the effectiveness of the LMDP framework in real robot control, in whichthe dynamics of the body and the environment have to be learned from experience. We first perform asimulation study of a pole swing-up task to evaluate the effect of the accuracy of the learned dynam-ics model on the derived the action policy. The result shows that a crude linear approximation of thenonlinear dynamics can still allow solution of the task, despite with a higher total cost.We then perform real robot experiments of a battery-catching task using our Spring Dog mobile robotplatform. The state is given by the position and the size of a battery in its camera view and two neck jointangles. The action is the velocities of two wheels, while the neck joints were controlled by a visual servocontroller. We test linear and bilinear dynamic models in tasks with quadratic and Guassian state costfunctions. In the quadratic cost task, the LMDP controller derived from a learned linear dynamics modelperformed equivalently with the optimal linear quadratic controller (LQR. In the non-quadratic task, theLMDP controller with a linear dynamics model showed the best performance. The results demonstratethe usefulness of the LMDP framework in real robot control even when simple linear models are usedfor dynamics learning.

  3. The suppression of scale-free fMRI brain dynamics across three different sources of effort: aging, task novelty and task difficulty.

    Science.gov (United States)

    Churchill, Nathan W; Spring, Robyn; Grady, Cheryl; Cimprich, Bernadine; Askren, Mary K; Reuter-Lorenz, Patricia A; Jung, Mi Sook; Peltier, Scott; Strother, Stephen C; Berman, Marc G

    2016-01-01

    There is growing evidence that fluctuations in brain activity may exhibit scale-free ("fractal") dynamics. Scale-free signals follow a spectral-power curve of the form P(f ) ∝ f(-β), where spectral power decreases in a power-law fashion with increasing frequency. In this study, we demonstrated that fractal scaling of BOLD fMRI signal is consistently suppressed for different sources of cognitive effort. Decreases in the Hurst exponent (H), which quantifies scale-free signal, was related to three different sources of cognitive effort/task engagement: 1) task difficulty, 2) task novelty, and 3) aging effects. These results were consistently observed across multiple datasets and task paradigms. We also demonstrated that estimates of H are robust across a range of time-window sizes. H was also compared to alternative metrics of BOLD variability (SDBOLD) and global connectivity (Gconn), with effort-related decreases in H producing similar decreases in SDBOLD and Gconn. These results indicate a potential global brain phenomenon that unites research from different fields and indicates that fractal scaling may be a highly sensitive metric for indexing cognitive effort/task engagement. PMID:27498696

  4. The suppression of scale-free fMRI brain dynamics across three different sources of effort: aging, task novelty and task difficulty

    Science.gov (United States)

    Churchill, Nathan W.; Spring, Robyn; Grady, Cheryl; Cimprich, Bernadine; Askren, Mary K.; Reuter-Lorenz, Patricia A.; Jung, Mi Sook; Peltier, Scott; Strother, Stephen C.; Berman, Marc G.

    2016-01-01

    There is growing evidence that fluctuations in brain activity may exhibit scale-free (“fractal”) dynamics. Scale-free signals follow a spectral-power curve of the form P(f ) ∝ f−β, where spectral power decreases in a power-law fashion with increasing frequency. In this study, we demonstrated that fractal scaling of BOLD fMRI signal is consistently suppressed for different sources of cognitive effort. Decreases in the Hurst exponent (H), which quantifies scale-free signal, was related to three different sources of cognitive effort/task engagement: 1) task difficulty, 2) task novelty, and 3) aging effects. These results were consistently observed across multiple datasets and task paradigms. We also demonstrated that estimates of H are robust across a range of time-window sizes. H was also compared to alternative metrics of BOLD variability (SDBOLD) and global connectivity (Gconn), with effort-related decreases in H producing similar decreases in SDBOLD and Gconn. These results indicate a potential global brain phenomenon that unites research from different fields and indicates that fractal scaling may be a highly sensitive metric for indexing cognitive effort/task engagement. PMID:27498696

  5. The suppression of scale-free fMRI brain dynamics across three different sources of effort: aging, task novelty and task difficulty.

    Science.gov (United States)

    Churchill, Nathan W; Spring, Robyn; Grady, Cheryl; Cimprich, Bernadine; Askren, Mary K; Reuter-Lorenz, Patricia A; Jung, Mi Sook; Peltier, Scott; Strother, Stephen C; Berman, Marc G

    2016-01-01

    There is growing evidence that fluctuations in brain activity may exhibit scale-free ("fractal") dynamics. Scale-free signals follow a spectral-power curve of the form P(f ) ∝ f(-β), where spectral power decreases in a power-law fashion with increasing frequency. In this study, we demonstrated that fractal scaling of BOLD fMRI signal is consistently suppressed for different sources of cognitive effort. Decreases in the Hurst exponent (H), which quantifies scale-free signal, was related to three different sources of cognitive effort/task engagement: 1) task difficulty, 2) task novelty, and 3) aging effects. These results were consistently observed across multiple datasets and task paradigms. We also demonstrated that estimates of H are robust across a range of time-window sizes. H was also compared to alternative metrics of BOLD variability (SDBOLD) and global connectivity (Gconn), with effort-related decreases in H producing similar decreases in SDBOLD and Gconn. These results indicate a potential global brain phenomenon that unites research from different fields and indicates that fractal scaling may be a highly sensitive metric for indexing cognitive effort/task engagement.

  6. Evaluation of linearly solvable Markov decision process with dynamic model learning in a mobile robot navigation task.

    Science.gov (United States)

    Kinjo, Ken; Uchibe, Eiji; Doya, Kenji

    2013-01-01

    Linearly solvable Markov Decision Process (LMDP) is a class of optimal control problem in which the Bellman's equation can be converted into a linear equation by an exponential transformation of the state value function (Todorov, 2009b). In an LMDP, the optimal value function and the corresponding control policy are obtained by solving an eigenvalue problem in a discrete state space or an eigenfunction problem in a continuous state using the knowledge of the system dynamics and the action, state, and terminal cost functions. In this study, we evaluate the effectiveness of the LMDP framework in real robot control, in which the dynamics of the body and the environment have to be learned from experience. We first perform a simulation study of a pole swing-up task to evaluate the effect of the accuracy of the learned dynamics model on the derived the action policy. The result shows that a crude linear approximation of the non-linear dynamics can still allow solution of the task, despite with a higher total cost. We then perform real robot experiments of a battery-catching task using our Spring Dog mobile robot platform. The state is given by the position and the size of a battery in its camera view and two neck joint angles. The action is the velocities of two wheels, while the neck joints were controlled by a visual servo controller. We test linear and bilinear dynamic models in tasks with quadratic and Guassian state cost functions. In the quadratic cost task, the LMDP controller derived from a learned linear dynamics model performed equivalently with the optimal linear quadratic regulator (LQR). In the non-quadratic task, the LMDP controller with a linear dynamics model showed the best performance. The results demonstrate the usefulness of the LMDP framework in real robot control even when simple linear models are used for dynamics learning.

  7. Evaluation of linearly solvable Markov decision process with dynamic model learning in a mobile robot navigation task.

    Science.gov (United States)

    Kinjo, Ken; Uchibe, Eiji; Doya, Kenji

    2013-01-01

    Linearly solvable Markov Decision Process (LMDP) is a class of optimal control problem in which the Bellman's equation can be converted into a linear equation by an exponential transformation of the state value function (Todorov, 2009b). In an LMDP, the optimal value function and the corresponding control policy are obtained by solving an eigenvalue problem in a discrete state space or an eigenfunction problem in a continuous state using the knowledge of the system dynamics and the action, state, and terminal cost functions. In this study, we evaluate the effectiveness of the LMDP framework in real robot control, in which the dynamics of the body and the environment have to be learned from experience. We first perform a simulation study of a pole swing-up task to evaluate the effect of the accuracy of the learned dynamics model on the derived the action policy. The result shows that a crude linear approximation of the non-linear dynamics can still allow solution of the task, despite with a higher total cost. We then perform real robot experiments of a battery-catching task using our Spring Dog mobile robot platform. The state is given by the position and the size of a battery in its camera view and two neck joint angles. The action is the velocities of two wheels, while the neck joints were controlled by a visual servo controller. We test linear and bilinear dynamic models in tasks with quadratic and Guassian state cost functions. In the quadratic cost task, the LMDP controller derived from a learned linear dynamics model performed equivalently with the optimal linear quadratic regulator (LQR). In the non-quadratic task, the LMDP controller with a linear dynamics model showed the best performance. The results demonstrate the usefulness of the LMDP framework in real robot control even when simple linear models are used for dynamics learning. PMID:23576983

  8. Continuous process tracing and the Iowa Gambling Task: Extending response dynamics to multialternative choice

    Directory of Open Access Journals (Sweden)

    Gregory J. Koop

    2011-12-01

    Full Text Available The history of judgment and decision making is defined by a trend toward increasingly nuanced explanations of the decision making process. Recently, process models have become incredibly sophisticated, yet the tools available to directly test these models have not kept pace. These increasingly complex process models require increasingly complex process data by which they can be adequately tested. We propose a new class of data collection that will facilitate evaluation of sophisticated process models. Tracking mouse paths during a continuous response provides an implicit measure of the growth of preference that produces a choice---rather than the current practice of recording just the button press that indicates that choice itself. Recent research in cognitive science (Spivey and Dale, 2006 has shown that cognitive processing can be revealed in these dynamic motor responses. Unlike current process methodologies, these response dynamics studies can demonstrate continuous competition between choice options and even online preference reversals. Here, in order to demonstrate the mechanics and utility of the methodology, we present an example response dynamics experiment utilizing a common multi-alternative decision task.

  9. A subjective evaluation of the minimum channel separation for reproducing binaural signals over loudspeakers

    DEFF Research Database (Denmark)

    Lacouture Parodi, Yesenia; Rubak, Per

    2011-01-01

    While there are a variety of methods and tradeoffs for creating the necessary crosstalk cancellation when reproducing a binaural signal through loudspeakers in a real environment, there are no studies that reveal the minimum required crosstalk. In the current study the authors simulated varying d...

  10. Detection and identification of monaural and binaural pitch contours in dyslexic listeners

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Poelmans, Hanne; Luts, Heleen;

    2010-01-01

    of dyslexic listeners to Huggins' pitch (HP). The present study clarified whether impaired binaural pitch perception is found in dyslexia. Results from a pitch contour identification test, performed in 31 dyslexic listeners and 31 matched controls, clearly showed that dyslexics perceived HP as well...

  11. Binaural Model-Based Speech Intelligibility Enhancement and Assessment in Hearing Aids

    NARCIS (Netherlands)

    Schlesinger, A.

    2012-01-01

    The enhancement of speech intelligibility in noise is still the main subject in hearing aid research. Based on the advanced results obtained with the hearing glasses, in the present research the speech intelligibility is even further improved by the application of binaural post-filters. The function

  12. Inferring reward prediction errors in patients with schizophrenia: a dynamic reward task for reinforcement learning

    Directory of Open Access Journals (Sweden)

    Chia-Tzu eLi

    2014-11-01

    Full Text Available Abnormalities in the dopamine system have long been implicated in explanations of reinforcement learning and psychosis. The updated reward prediction error (RPE—a discrepancy between the predicted and actual rewards—is thought to be encoded by dopaminergic neurons. Dysregulation of dopamine systems could alter the appraisal of stimuli and eventually lead to schizophrenia. Accordingly, the measurement of RPE provides a potential behavioral index for the evaluation of brain dopamine activity and psychotic symptoms. Here, we assess two features potentially crucial to the RPE process, namely belief formation and belief perseveration, via a probability learning task and reinforcement-learning modeling. Forty-five patients with schizophrenia (26 high-psychosis and 19 low-psychosis, based on their p1 and p3 scores in the positive-symptom subscales of the Positive and Negative Syndrome Scale (PANSS and 24 controls were tested in a feedback-based dynamic reward task for their RPE-related decision making. While task scores across the three groups were similar, matching law analysis revealed that the reward sensitivities of both psychosis groups were lower than that of controls. Trial-by-trial data were further fit with a reinforcement learning model using the Bayesian estimation approach. Model fitting results indicated that both psychosis groups tend to update their reward values more rapidly than controls. Moreover, among the three groups, high-psychosis patients had the lowest degree of choice perseveration. Lumping patients’ data together, we also found that patients’ perseveration appears to be negatively correlated (p = .09, trending towards significance with their PANSS p1+p3 scores. Our method provides an alternative for investigating reward-related learning and decision making in basic and clinical settings.

  13. Dynamic Programming for Re-Mapping Noisy Fixations in Translation Tasks

    DEFF Research Database (Denmark)

    Carl, Michael

    2013-01-01

    drifted center of the observed fixation onto the symbol directly below it. In this paper I extend this naïve fixation-to-symbol mapping by introducing background knowledge about the translation task. In a first step, the sequence of fixation-to- symbol mappings is extended into a lattice of several...... possible fixated symbols, including those on the line above and below the naïve fixation mapping. In a second step a dynamic programming algorithm applies a number of heuristics to find the best path through the lattice, based on the probable distance in characters, in words and in pixels between...... successive fixations and the symbol locations, so as to smooth the gazing path according to the background gazing model. A qualitative and quantitative evaluation shows that the algorithm increases the accuracy of the re-mapped symbol sequence....

  14. Using task dynamics to quantify the affordances of throwing for long distance and accuracy.

    Science.gov (United States)

    Wilson, Andrew D; Weightman, Andrew; Bingham, Geoffrey P; Zhu, Qin

    2016-07-01

    In 2 experiments, the current study explored how affordances structure throwing for long distance and accuracy. In Experiment 1, 10 expert throwers (from baseball, softball, and cricket) threw regulation tennis balls to hit a vertically oriented 4 ft × 4 ft target placed at each of 9 locations (3 distances × 3 heights). We measured their release parameters (angle, speed, and height) and showed that they scaled their throws in response to changes in the target's location. We then simulated the projectile motion of the ball and identified a continuous subspace of release parameters that produce hits to each target location. Each subspace describes the affordance of our target to be hit by a tennis ball moving in a projectile motion to the relevant location. The simulated affordance spaces showed how the release parameter combinations required for hits changed with changes in the target location. The experts tracked these changes in their performance and were successful in hitting the targets. We next tested unusual (horizontal) targets that generated correspondingly different affordance subspaces to determine whether the experts would track the affordance to generate successful hits. Do the experts perceive the affordance? They do. In Experiment 2, 5 cricketers threw to hit either vertically or horizontally oriented targets and successfully hit both, exhibiting release parameters located within the requisite affordance subspaces. We advocate a task dynamical approach to the study of affordances as properties of objects and events in the context of tasks as the future of research in this area. (PsycINFO Database Record PMID:26766510

  15. Binaural fusion and listening effort in children who use bilateral cochlear implants: a psychoacoustic and pupillometric study.

    Directory of Open Access Journals (Sweden)

    Morrison M Steel

    Full Text Available Bilateral cochlear implants aim to provide hearing to both ears for children who are deaf and promote binaural/spatial hearing. Benefits are limited by mismatched devices and unilaterally-driven development which could compromise the normal integration of left and right ear input. We thus asked whether children hear a fused image (ie. 1 vs 2 sounds from their bilateral implants and if this "binaural fusion" reduces listening effort. Binaural fusion was assessed by asking 25 deaf children with cochlear implants and 24 peers with normal hearing whether they heard one or two sounds when listening to bilaterally presented acoustic click-trains/electric pulses (250 Hz trains of 36 ms presented at 1 Hz. Reaction times and pupillary changes were recorded simultaneously to measure listening effort. Bilaterally implanted children heard one image of bilateral input less frequently than normal hearing peers, particularly when intensity levels on each side were balanced. Binaural fusion declined as brainstem asymmetries increased and age at implantation decreased. Children implanted later had access to acoustic input prior to implantation due to progressive deterioration of hearing. Increases in both pupil diameter and reaction time occurred as perception of binaural fusion decreased. Results indicate that, without binaural level cues, children have difficulty fusing input from their bilateral implants to perceive one sound which costs them increased listening effort. Brainstem asymmetries exacerbate this issue. By contrast, later implantation, reflecting longer access to bilateral acoustic hearing, may have supported development of auditory pathways underlying binaural fusion. Improved integration of bilateral cochlear implant signals for children is required to improve their binaural hearing.

  16. A Model for Task Design with Focus on Exploration, Explanation, and Generalization in a Dynamic Geometry Environment

    Science.gov (United States)

    Fahlgren, Maria; Brunström, Mats

    2014-01-01

    The increasing availability of new technologies in schools provides new possibilities for the integration of technology in mathematics education. However, research has shown that there is a need for new kinds of task that utilize the affordances provided by new technology. Numerous studies have demonstrated that dynamic geometry environments…

  17. Using Heuristic Value Prediction and Dynamic Task Granularity Resizing to Improve Software Speculation

    Directory of Open Access Journals (Sweden)

    Fan Xu

    2014-01-01

    Full Text Available Exploiting potential thread-level parallelism (TLP is becoming the key factor to improving performance of programs on multicore or many-core systems. Among various kinds of parallel execution models, the software-based speculative parallel model has become a research focus due to its low cost, high efficiency, flexibility, and scalability. The performance of the guest program under the software-based speculative parallel execution model is closely related to the speculation accuracy, the control overhead, and the rollback overhead of the model. In this paper, we first analyzed the conventional speculative parallel model and presented an analytic model of its expectation of the overall overhead, then optimized the conventional model based on the analytic model, and finally proposed a novel speculative parallel model named HEUSPEC. The HEUSPEC model includes three key techniques, namely, the heuristic value prediction, the value based correctness checking, and the dynamic task granularity resizing. We have implemented the runtime system of the model in ANSI C language. The experiment results show that when the speedup of the HEUSPEC model can reach 2.20 on the average (15% higher than conventional model when depth is equal to 3 and 4.51 on the average (12% higher than conventional model when speculative depth is equal to 7. Besides, it shows good scalability and lower memory cost.

  18. The CAVA corpus: synchronised stereoscopic and binaural datasets with head movements

    OpenAIRE

    Arnaud, Elise; Christensen, Heidi; Lu, Yan-Chen; Barker, Jon; Khalidov, Vasil; Hansard, Miles; Holveck, Bertrand; Mathieu, Herve; Narasimha, Ramya; Taillant, Elise; Forbes, Florence; Horaud, Radu

    2008-01-01

    International audience This paper describes the acquisition and content of a new multi-modal database. Some tools for making use of the data streams are also presented. The Computational Audio- Visual Analysis (CAVA) database is a unique collection of three synchronised data streams obtained from a binaural microphone pair, a stereoscopic camera pair and a head tracking device. All recordings are made from the perspective of a person; i.e. what would a human with natural head movements see...

  19. A Combined Feedback and Noise Cancellation Algorithm for Binaural Hearing Aids

    OpenAIRE

    Lee, H. -W.; JEON, M.-Y.

    2011-01-01

    This paper proposes an adaptive algorithm for the combined acoustic feedback and noise cancellation in the binaural hearing aids. The proposed algorithm is based on dual microphones for feedback cancellation and the beamforming method for noise cancellation. The coefficients of feedback canceller are updated after subtracting the speech signal from the input signal by dual microphones. And the noise canceller reduces the noise signal in the residual signal excluding the speech by the beam...

  20. Improving speech intelligibility for binaural voice transmission under disturbing noise and reverberation using virtual speaker lateralization

    OpenAIRE

    A.L. Padilla Ortiz; F. Orduña-Bustamante

    2015-01-01

    Subjective speech intelligibility tests were carried out in order to investigate strategies to improve speech intelligibility in binaural voice transmission when listening from different azimuth angles under adverse listening conditions. Phonetically balanced bi-syllable meaningful words in Spanish were used as speech material. The speech signal was played back through headphones, undisturbed, and also with the addition of high levels of disturbing noise or reverberation, with a signal to ...

  1. A Distributed Cooperative Dynamic Task Planning Algorithm for Multiple Satellites Based on Multi-agent Hybrid Learning

    Institute of Scientific and Technical Information of China (English)

    WANG Chong; LI Jun; JING Ning; WANG Jun; CHEN Hao

    2011-01-01

    Traditionally,heuristic re-planning algorithms are used to tackle the problem of dynamic task planning for multiple satellites.However,the traditional heuristic strategies depend on the concrete tasks,which often affect the result's optimality.Noticing that the historical information of cooperative task planning will impact the latter planning results,we propose a hybrid learning algorithrn for dynamic multi-satellite task planning,which is based on the multi-agent reinforcement learning of policy iteration and the transfer learning.The reinforcement learning strategy of each satellite is described with neural networks.The policy neural network individuals with the best topological structure and weights are found by applying co-evolutionary search iteratively.To avoid the failure of the historical learning caused by the randomly occurring observation requests,a novel approach is proposed to balance the quality and efficiency of the task planning,which converts the historical leaming strategy to the current initial learning strategy by applying the transfer learning algorithm.The simulations and analysis show the feasibility and adaptability of the proposed approach especially for the situation with randomly occurring observation requests.

  2. STATIC AND DYNAMIC POSTURE CONTROL IN POSTLINGUAL COCHLEAR IMPLANTED PATIENTS: Effects of dual-tasking, visual and auditory inputs suppression

    Directory of Open Access Journals (Sweden)

    BERNARD DEMANZE eLaurence

    2014-01-01

    Full Text Available Posture control is based on central integration of multisensory inputs, and on internal representation of body orientation in space. This multisensory feedback regulates posture control and continuously updates the internal model of body’s position which in turn forwards motor commands adapted to the environmental context and constraints. The peripheral localization of the vestibular system, close to the cochlea, makes vestibular damage possible following cochlear implant (CI surgery. Impaired vestibular function in CI patients, if any, may have a strong impact on posture stability. The simple postural task of quiet standing is generally paired with cognitive activity in most day life conditions, leading therefore to competition for attentional resources in dual-tasking, and increased risk of fall particularly in patients with impaired vestibular function. This study was aimed at evaluating the effects of post-lingual cochlear implantation on posture control in adult deaf patients. Possible impairment of vestibular function was assessed by comparing the postural performance of patients to that of age-matched healthy subjects during a simple postural task performed in static and dynamic conditions, and during dual-tasking with a visual or auditory memory task. Postural tests were done in eyes open (EO and eyes closed (EC conditions, with the cochlear implant activated (ON or not (OFF. Results showed that the CI patients significantly reduced limits of stability and increased postural instability in static conditions. In dynamic conditions, they spent considerably more energy to maintain equilibrium, and their head was stabilized neither in space nor on trunk while the controls showed a whole body rigidification strategy. Hearing (prosthesis on as well as dual-tasking did not really improve the dynamic postural performance of the CI patients. We conclude that CI patients become strongly visual dependent mainly in challenging postural conditions.

  3. A Link Loss Model for the On-Body Propagation Channel for Binaural Hearing Aids

    Science.gov (United States)

    Chandra, Rohit; Johansson, Anders J.

    2013-12-01

    Binaural hearing aids communicate with each other through a wireless link for synchronization. A propagation model is needed to estimate the ear-to-ear link loss for such binaural hearing aids. The link loss is a critical parameter in a link budget to decide the sensitivity of the transceiver. In this paper, we have presented a model for the deterministic component of the ear-to-ear link loss. The model takes into account the dominant paths having most of the power of the creeping wave from the transceiver in one ear to the transceiver in other ear and the effect of the protruding part of the outer ear called pinna. Simulations are done to validate the model using in-the-ear (ITE) placement of antennas at 2.45 GHz on two heterogeneous phantoms of different age-group and body size. The model agrees with the simulations. The ear-to-ear link loss between the antennas for the binaural hearing aids in the homogeneous SAM phantom is compared with a heterogeneous phantom. It is found that the absence of the pinna and the lossless shell in the SAM phantom underestimate the link loss. This is verified by the measurements on a phantom where we have included the pinnas fabricated by 3D-printing.

  4. Binaural detection with narrowband and wideband reproducible noise maskers: II. Results for rabbit

    Science.gov (United States)

    Zheng, Ling; Early, Susan J.; Mason, Christine R.; Idrobo, Fabio; Harrison, J. Michael; Carney, Laurel H.

    2002-01-01

    Binaural detection with narrowband and wideband noise maskers was examined by using a Pavlovian-conditioned eyeblink response in rabbits. The target was a tone at 500 Hz, and the maskers were ten individual noise samples having one of two bandwidths, 200 Hz (410 Hz to 610 Hz) or 2900 Hz (100 Hz to 3 kHz). The narrowband noise maskers were created by filtering the wideband noise maskers such that the two sets of maskers had identical spectra in the 200-Hz frequency region surrounding the tone. The responses across the set of noise maskers were compared across bandwidths and across interaural configurations (N0S0 and N0Sπ). Responses across the set of noise waveforms were not strongly correlated across bandwidths; this result is inconsistent with models for binaural detection that depend only upon the narrow band of energy centered at the frequency of the target tone. Responses were correlated across interaural configurations for the wideband masker condition, but not for the narrowband masker. All of these results were consistent with the companion study of human listeners [Evilsizer et al., J. Acoust. Soc. Am. 111, 336-345 (2002)] and with the results of human studies of binaural detection that used only wideband [Gilkey et al., J. Acoust. Soc. Am. 78, 1207-1219 (1985)] or narrowband [Isabelle and Colburn, J. Acoust. Soc. Am. 89, 352-259 (1991)] individual noise maskers.

  5. A Link Loss Model for the On-body Propagation Channel for Binaural Hearing Aids

    CERN Document Server

    Chandra, Rohit

    2013-01-01

    Binaural hearing aids communicate with each other through a wireless link for synchronization. A propagation model is needed to estimate the ear-to-ear link loss for such binaural hearing aids. The link loss is a critical parameter in a link budget to decide the sensitivity of the transceiver. In this paper, we have presented a model for the deterministic component of the ear-to-ear link loss. The model takes into account the dominant paths having most of the power of the creeping wave from the transceiver in one ear to the transceiver in other ear and the effect of the protruding part of the outer ear called pinna. Simulations are done to validate the model using in-the-ear (ITE) placement of antennas at 2.45 GHz on two heterogeneous phantoms of different age-group and body size. The model agrees with the simulations. The ear-to-ear link loss between the antennas for the binaural hearing aids in the homogeneous SAM phantom is compared with a heterogeneous phantom. It is found that the absence of the pinna an...

  6. Dynamically Allocated Hub in Task-Evoked Network Predicts the Vulnerable Prefrontal Locus for Contextual Memory Retrieval in Macaques.

    Directory of Open Access Journals (Sweden)

    Takahiro Osada

    2015-06-01

    Full Text Available Neuroimaging and neurophysiology have revealed that multiple areas in the prefrontal cortex (PFC are activated in a specific memory task, but severity of impairment after PFC lesions is largely different depending on which activated area is damaged. The critical relationship between lesion sites and impairments has not yet been given a clear mechanistic explanation. Although recent works proposed that a whole-brain network contains hubs that play integrative roles in cortical information processing, this framework relying on an anatomy-based structural network cannot account for the vulnerable locus for a specific task, lesioning of which would bring impairment. Here, we hypothesized that (i activated PFC areas dynamically form an ordered network centered at a task-specific "functional hub" and (ii the lesion-effective site corresponds to the "functional hub," but not to a task-invariant "structural hub." To test these hypotheses, we conducted functional magnetic resonance imaging experiments in macaques performing a temporal contextual memory task. We found that the activated areas formed a hierarchical hub-centric network based on task-evoked directed connectivity, differently from the anatomical network reflecting axonal projection patterns. Using a novel simulated-lesion method based on support vector machine, we estimated severity of impairment after lesioning of each area, which accorded well with a known dissociation in contextual memory impairment in macaques (impairment after lesioning in area 9/46d, but not in area 8Ad. The predicted severity of impairment was proportional to the network "hubness" of the virtually lesioned area in the task-evoked directed connectivity network, rather than in the anatomical network known from tracer studies. Our results suggest that PFC areas dynamically and cooperatively shape a functional hub-centric network to reallocate the lesion-effective site depending on the cognitive processes, apart from

  7. Setup for demonstrating interactive binaural synthesis for telepresence applications

    DEFF Research Database (Denmark)

    Madsen, Esben; Olesen, Søren Krarup; Markovic, Milos;

    2011-01-01

    3 main tasks: Tracking coordinates are combined to calculate directions. This is handled by sharing "global" coordinates across the sites and adding local changes with a low latency, ending with a "direction of sound" for each source. Audio is recorded and transmitted over network. Here bandwidth...

  8. Towards a cognitive robotics methodology for reward-based decision-making: dynamical systems modelling of the Iowa Gambling Task

    Science.gov (United States)

    Lowe, Robert; Ziemke, Tom

    2010-09-01

    The somatic marker hypothesis (SMH) posits that the role of emotions and mental states in decision-making manifests through bodily responses to stimuli of import to the organism's welfare. The Iowa Gambling Task (IGT), proposed by Bechara and Damasio in the mid-1990s, has provided the major source of empirical validation to the role of somatic markers in the service of flexible and cost-effective decision-making in humans. In recent years the IGT has been the subject of much criticism concerning: (1) whether measures of somatic markers reveal that they are important for decision-making as opposed to behaviour preparation; (2) the underlying neural substrate posited as critical to decision-making of the type relevant to the task; and (3) aspects of the methodological approach used, particularly on the canonical version of the task. In this paper, a cognitive robotics methodology is proposed to explore a dynamical systems approach as it applies to the neural computation of reward-based learning and issues concerning embodiment. This approach is particularly relevant in light of a strongly emerging alternative hypothesis to the SMH, the reversal learning hypothesis, which links, behaviourally and neurocomputationally, a number of more or less complex reward-based decision-making tasks, including the 'A-not-B' task - already subject to dynamical systems investigations with a focus on neural activation dynamics. It is also suggested that the cognitive robotics methodology may be used to extend systematically the IGT benchmark to more naturalised, but nevertheless controlled, settings that might better explore the extent to which the SMH, and somatic states per se, impact on complex decision-making.

  9. EZDCP:A new static task scheduling algorithm with edge-zeroing based on dynamic critical paths

    Institute of Scientific and Technical Information of China (English)

    陈志刚; 华强胜

    2003-01-01

    A new static task scheduling algorithm named edge-zeroing based on dynamic critical paths is proposed.The main ideas of the algorithm are as follows: firstly suppose that all of the tasks are in different clusters; secondly, select one of the critical paths of the partially clustered directed acyclic graph; thirdly, try to zero one of graph communication edges; fourthly, repeat above three processes until all edges are zeroed; finally, check the generated clusters to see if some of them can be further merged without increasing the parallel time. Comparisons of the previous algorithms with edge-zeroing based on dynamic critical paths show that the new algorithm has not only a low complexity but also a desired performance comparable or even better on average to much higher complexity heuristic algorithms.

  10. Spatial and temporal task characteristics as stress: a test of the dynamic adaptability theory of stress, workload, and performance.

    Science.gov (United States)

    Szalma, James L; Teo, Grace W L

    2012-03-01

    The goal for this study was to test assertions of the dynamic adaptability theory of stress, which proposes two fundamental task dimensions, information rate (temporal properties of a task) and information structure (spatial properties of a task). The theory predicts adaptive stability across stress magnitudes, with progressive and precipitous changes in adaptive response manifesting first as increases in perceived workload and stress and then as performance failure. Information structure was manipulated by varying the number of displays to be monitored (1, 2, 4 or 8 displays). Information rate was manipulated by varying stimulus presentation rate (8, 12, 16, or 20 events/min). A signal detection task was used in which critical signals were pairs of digits that differed by 0 or 1. Performance accuracy declined and workload and stress increased as a function of increased task demand, with a precipitous decline in accuracy at the highest demand levels. However, the form of performance change as well as the pattern of relationships between speed and accuracy and between performance and workload/stress indicates that some aspects of the theory need revision. Implications of the results for the theory and for future research are discussed.

  11. Novel modeling of task versus rest brain state predictability using a dynamic time warping spectrum: comparisons and contrasts with other standard measures of brain dynamics

    Directory of Open Access Journals (Sweden)

    Martin eDinov

    2016-05-01

    Full Text Available Dynamic time warping, or DTW, is a powerful and domain-general sequence alignment method for computing a similarity measure. Such dynamic programming-based techniques like DTW are now the backbone and driver of most bioinformatics methods and discoveries. In neuroscience it has had far less use, though this has begun to change. We wanted to explore new ways of applying DTW, not simply as a measure with which to cluster or compare similarity between features but in a conceptually different way. We have used DTW to provide a more interpretable spectral description of the data, compared to standard approaches such as the Fourier and related transforms. The DTW approach and standard discrete Fourier transform (DFT are assessed against benchmark measures of neural dynamics. These include EEG microstates, EEG avalanches and the sum squared error (SSE from a multilayer perceptron (MLP prediction of the EEG timeseries, and simultaneously acquired FMRI BOLD signal. We explored the relationships between these variables of interest in an EEG-FMRI dataset acquired during a standard cognitive task, which allowed us to explore how DTW differentially performs in different task settings. We found that despite strong correlations between DTW and DFT-spectra, DTW was a better predictor for almost every measure of brain dynamics. Using these DTW measures, we show that predictability is almost always higher in task than in rest states, which is consistent to other theoretical and empirical findings, providing additional evidence for the utility of the DTW approach.

  12. Novel Modeling of Task vs. Rest Brain State Predictability Using a Dynamic Time Warping Spectrum: Comparisons and Contrasts with Other Standard Measures of Brain Dynamics

    Science.gov (United States)

    Dinov, Martin; Lorenz, Romy; Scott, Gregory; Sharp, David J.; Fagerholm, Erik D.; Leech, Robert

    2016-01-01

    Dynamic time warping, or DTW, is a powerful and domain-general sequence alignment method for computing a similarity measure. Such dynamic programming-based techniques like DTW are now the backbone and driver of most bioinformatics methods and discoveries. In neuroscience it has had far less use, though this has begun to change. We wanted to explore new ways of applying DTW, not simply as a measure with which to cluster or compare similarity between features but in a conceptually different way. We have used DTW to provide a more interpretable spectral description of the data, compared to standard approaches such as the Fourier and related transforms. The DTW approach and standard discrete Fourier transform (DFT) are assessed against benchmark measures of neural dynamics. These include EEG microstates, EEG avalanches, and the sum squared error (SSE) from a multilayer perceptron (MLP) prediction of the EEG time series, and simultaneously acquired FMRI BOLD signal. We explored the relationships between these variables of interest in an EEG-FMRI dataset acquired during a standard cognitive task, which allowed us to explore how DTW differentially performs in different task settings. We found that despite strong correlations between DTW and DFT-spectra, DTW was a better predictor for almost every measure of brain dynamics. Using these DTW measures, we show that predictability is almost always higher in task than in rest states, which is consistent to other theoretical and empirical findings, providing additional evidence for the utility of the DTW approach. PMID:27242502

  13. The temporal dynamics of metacognition: Dissociating task-related activity from later metacognitive processes.

    Science.gov (United States)

    Desender, Kobe; Van Opstal, Filip; Hughes, Gethin; Van den Bussche, Eva

    2016-02-01

    In recent years, neuroscience research spent much effort in revealing brain activity related to metacognition. Despite this endeavor, it remains unclear exactly when metacognitive experiences develop during task performance. To investigate this, the current study used EEG to temporally and spatially dissociate task-related activity from metacognitive activity. In a masked priming paradigm, metacognitive experiences of difficulty were induced by manipulating congruency between prime and target. As expected, participants more frequently rated incongruent trials as difficult and congruent trials as easy, while being completely unable to perceive the masked primes. Results showed that both the N2 and the P3 ERP components were modulated by congruency, but that only the P3 modulation interacted with metacognitive experiences. Single-trial analysis additionally showed that the magnitude of the P3 modulation by congruency accurately predicted the metacognitive response. Source localization indicated that the N2 task-related activity originated in the ACC, whereas the P3-interplay between task-related activation and metacognitive experiences originated from the precuneus. We conclude that task-related activity can be dissociated from later metacognitive processing.

  14. Investigating Conversational Dynamics: Interactive Alignment, Interpersonal Synergy, and Collective Task Performance.

    Science.gov (United States)

    Fusaroli, Riccardo; Tylén, Kristian

    2016-01-01

    This study investigates interpersonal processes underlying dialog by comparing two approaches, interactive alignment and interpersonal synergy, and assesses how they predict collective performance in a joint task. While the interactive alignment approach highlights imitative patterns between interlocutors, the synergy approach points to structural organization at the level of the interaction-such as complementary patterns straddling speech turns and interlocutors. We develop a general, quantitative method to assess lexical, prosodic, and speech/pause patterns related to the two approaches and their impact on collective performance in a corpus of task-oriented conversations. The results show statistical presence of patterns relevant for both approaches. However, synergetic aspects of dialog provide the best statistical predictors of collective performance and adding aspects of the alignment approach does not improve the model. This suggests that structural organization at the level of the interaction plays a crucial role in task-oriented conversations, possibly constraining and integrating processes related to alignment.

  15. A Binaural Cochlear Implant Sound Coding Strategy Inspired by the Contralateral Medial Olivocochlear Reflex

    Science.gov (United States)

    Eustaquio-Martín, Almudena; Stohl, Joshua S.; Wolford, Robert D.; Schatzer, Reinhold; Wilson, Blake S.

    2016-01-01

    Objectives: In natural hearing, cochlear mechanical compression is dynamically adjusted via the efferent medial olivocochlear reflex (MOCR). These adjustments probably help understanding speech in noisy environments and are not available to the users of current cochlear implants (CIs). The aims of the present study are to: (1) present a binaural CI sound processing strategy inspired by the control of cochlear compression provided by the contralateral MOCR in natural hearing; and (2) assess the benefits of the new strategy for understanding speech presented in competition with steady noise with a speech-like spectrum in various spatial configurations of the speech and noise sources. Design: Pairs of CI sound processors (one per ear) were constructed to mimic or not mimic the effects of the contralateral MOCR on compression. For the nonmimicking condition (standard strategy or STD), the two processors in a pair functioned similarly to standard clinical processors (i.e., with fixed back-end compression and independently of each other). When configured to mimic the effects of the MOCR (MOC strategy), the two processors communicated with each other and the amount of back-end compression in a given frequency channel of each processor in the pair decreased/increased dynamically (so that output levels dropped/increased) with increases/decreases in the output energy from the corresponding frequency channel in the contralateral processor. Speech reception thresholds in speech-shaped noise were measured for 3 bilateral CI users and 2 single-sided deaf unilateral CI users. Thresholds were compared for the STD and MOC strategies in unilateral and bilateral listening conditions and for three spatial configurations of the speech and noise sources in simulated free-field conditions: speech and noise sources colocated in front of the listener, speech on the left ear with noise in front of the listener, and speech on the left ear with noise on the right ear. In both bilateral and

  16. 4D time-frequency representation for binaural speech signal processing

    Science.gov (United States)

    Mikhael, Raed; Szu, Harold H.

    2006-04-01

    Hearing is the ability to detect and process auditory information produced by the vibrating hair cilia residing in the corti of the ears to the auditory cortex of the brain via the auditory nerve. The primary and secondary corti of the brain interact with one another to distinguish and correlate the received information by distinguishing the varying spectrum of arriving frequencies. Binaural hearing is nature's way of employing the power inherent in working in pairs to process information, enhance sound perception, and reduce undesired noise. One ear might play a prominent role in sound recognition, while the other reinforces their perceived mutual information. Developing binaural hearing aid devices can be crucial in emulating the working powers of two ears and may be a step closer to significantly alleviating hearing loss of the inner ear. This can be accomplished by combining current speech research to already existing technologies such as RF communication between PDAs and Bluetooth. Ear Level Instrument (ELI) developed by Micro-tech Hearing Instruments and Starkey Laboratories is a good example of a digital bi-directional signal communicating between a PDA/mobile phone and Bluetooth. The agreement and disagreement of arriving auditory information to the Bluetooth device can be classified as sound and noise, respectively. Finding common features of arriving sound using a four coordinate system for sound analysis (four dimensional time-frequency representation), noise can be greatly reduced and hearing aids would become more efficient. Techniques developed by Szu within an Artificial Neural Network (ANN), Blind Source Separation (BSS), Adaptive Wavelets Transform (AWT), and Independent Component Analysis (ICA) hold many possibilities to the improvement of acoustic segmentation of phoneme, all of which will be discussed in this paper. Transmitted and perceived acoustic speech signal will improve, as the binaural hearing aid will emulate two ears in sound

  17. Directional loudness in an anechoic sound field, head-related transfer functions, and binaural summation

    DEFF Research Database (Denmark)

    Sivonen, Ville Pekka; Ellermeier, Wolfgang

    2006-01-01

    The effect of sound incidence angle on loudness was investigated using real sound sources positioned in an anechoic chamber. Eight normal-hearing listeners produced loudness matches between a frontal reference location and seven sources placed at other directions, both in the horizontal and median...... a range of up to 10 dB, exhibiting considerable frequency dependence, but only minor effects of overall level. The pattern of results varied substantially between subjects, but was largely accounted for by variations in individual head-related transfer functions. Modeling of binaural loudness based...

  18. ROBUST LOCALISATION OF MULTIPLE SPEAKERS EXPLOITING HEAD MOVEMENTS AND MULTI-CONDITIONAL TRAINING OF BINAURAL CUES

    DEFF Research Database (Denmark)

    May, Tobias; Ma, Ning; Brown, Guy

    2015-01-01

    This paper addresses the problem of localising multiple competing speakers in the presence of room reverberation, where sound sources can be positioned at any azimuth on the horizontal plane. To reduce the amount of front-back confusions which can occur due to the sim- ilarity of interaural time...... differences (ITDs) and interaural level dif- ferences (ILDs) in the front and rear hemifield, a machine hearing system is presented which combines supervised learning of binaural cues using multi-conditional training (MCT) with a head movement strategy. A systematic evaluation showed that this approach...

  19. Blind estimation of the number of speech source in reverberant multisource scenarios based on binaural signals

    DEFF Research Database (Denmark)

    May, Tobias; van de Par, Steven

    2012-01-01

    In this paper we present a new approach for estimating the number of active speech sources in the presence of interfering noise sources and reverberation. First, a binaural front-end is used to detect the spatial positions of all active sound sources, resulting in a binary mask for each candidate...... on a support vector machine (SVM) classifier. A systematic analysis shows that the proposed algorithm is able to blindly determine the number and the corresponding spatial positions of speech sources in multisource scenarios and generalizes well to unknown acoustic conditions...

  20. Are binaural recordings needed for subjective and objective annoyance assessment of traffic noise?

    DEFF Research Database (Denmark)

    Rodríguez, Estefanía Cortés; Song, Wookeun; Brunskog, Jonas;

    2011-01-01

    Humans are annoyed when they are exposed to environmental noise. Traditional measures such as sound pressure levels may not correlate well with how humans perceive annoyance, therefore it is important to investigate psychoacoustic metrics that may correlate better with the perceived annoyance...... of environmental noise than the A-weighted equivalent sound pressure level. This study examined whether the use of binaural recordings of sound events improves the correlation between the objective metrics and the perceived annoyance, particularly for road traffic noise. Metrics based on measurement with a single...

  1. Age Differences between Children and Young Adults in the Dynamics of Dual-Task Prioritization: Body (Balance) versus Mind (Memory)

    Science.gov (United States)

    Schaefer, Sabine; Krampe, Ralf Th.; Lindenberger, Ulman; Baltes, Paul B.

    2008-01-01

    Task prioritization can lead to trade-off patterns in dual-task situations. The authors compared dual-task performances in 9- and 11-year-old children and young adults performing a cognitive task and a motor task concurrently. The motor task required balancing on an ankle-disc board. Two cognitive tasks measured working memory and episodic memory…

  2. Modeling Human Dynamics in Combined Ramp-Following and Disturbance-Rejection Tasks

    NARCIS (Netherlands)

    Pool, D.M.; Van Paassen, M.M.; Mulder, M.

    2010-01-01

    This paper investigates the modeling of humanmanual control behavior for pursuit tracking tasks in which target forcing functions consisting of multiple ramp-like changes in target attitude are used. Due to the use of a pursuit display and the predictability of such forcing function signals, it can

  3. Computer modeling of tasks in dynamics of viscoelastic thin-walled elements in structures of variable thickness

    Directory of Open Access Journals (Sweden)

    R.A. Abdikarimov

    2014-08-01

    Full Text Available The paper presents a numerical method and algorithm for solving tasks in dynamics of viscoelastic thin-walled elements in structures of variable thickness. The equations of motion concerning deflections are described by partial integro-differential equations (PIDE. Using Bubnov-Galerkin’s method, based on the polynomial approximation of deflections, the task is limited to the study of the system of ordinary IDEs, where the independent variable is time. The solution to the system of IDEs is obtained by the offered numerical method, which results into the algorithm of the numerical solution and the program in the Delphi algorithmic language. The study of nonlinear vibrations of thin-walled elements in structures, allowing for variable thickness in the geometrical nonlinear statement, has enabled revealing a number of mechanical effects. Depending on physico-mechanical and geometrical parameters of the considered viscoelastic thin-walled elements in structures, the authors reccommend how to use the rigidity of the system.

  4. Motor intensive anti-gravity training improves performance in dynamic balance related tasks in persons with Parkinson's disease.

    Science.gov (United States)

    Malling, Anne Sofie B; Jensen, Bente R

    2016-01-01

    Recent studies indicate that the effect of training on motor performance in persons with Parkinson's disease (PDP) is dependent on motor intensity. However, training of high motor intensity can be hard to apply in PDP due to e.g. bradykinesia, rigidity, tremor and postural instability. Therefore, the aim was to study the effect of motor intensive training performed in a safe anti-gravity environment using lower-body positive pressure (LBPP) technology on performance during dynamic balance related tasks. Thirteen male PDP went through an 8-week control period followed by 8 weeks of motor intensive antigravity training. Seventeen healthy males constituted a control group (CON). Performance during a five repetition sit-to-stand test (STS; sagittal plane) and a dynamic postural balance test (DPB; transversal plane) was evaluated. Effect measures were completion time, functional rates of force development, directional changes and force variance. STS completion time improved by 24% to the level of CON which was explained by shorter sitting-time and standing-time and larger numeric rate of force change during lowering to the chair, indicating faster vertical directional change and improved relaxation. DPB completion time tended to improve and was accompanied by improvements of functional medial and lateral rates of force development and higher vertical force variance during DPB. Our results suggest that the performance improvements may relate to improved inter-limb coordination. It is concluded that 8 weeks of motor intensive training in a safe LBPP environment improved performance during dynamic balance related tasks in PDP.

  5. The use of cognitive cues for anticipatory strategies in a dynamic postural control task - validation of a novel approach to dual-task testing

    DEFF Research Database (Denmark)

    Læssøe, Uffe; Grarup, Bo; Bangshaab, Jette

    2016-01-01

    Introduction: Dual-task testing is relevant in the assessment of postural control. A combination of a primary (motor) and a secondary (distracting cognitive) tasks is most often used. It remains a challenge however, to standardize and monitor the cognitive task. In this study a new dual-task test......Introduction: Dual-task testing is relevant in the assessment of postural control. A combination of a primary (motor) and a secondary (distracting cognitive) tasks is most often used. It remains a challenge however, to standardize and monitor the cognitive task. In this study a new dual......-task testing approach with a facilitating, rather than distracting, cognitive component was evaluated.Methods: Thirty-one community-dwelling elderly and fifteen young people were tested with respect to their ability to use anticipatory postural control strategies. The motor task consisted of twenty......-five repetitive tasks in which the participants needed to exceed their limit of stability in order to touch one out of eight lights. The participants performed three tests. In two of the tests the color cues of the lights allowed the participants to utilize cognitive strategies to plan their next movement...

  6. Investigating conversational dynamics: Interactive alignment, Interpersonal synergy, and collective task performance

    DEFF Research Database (Denmark)

    Fusaroli, Riccardo; Tylén, Kristian

    2016-01-01

    This study investigates interpersonal processes underlying dialog by comparing two approaches, interactive alignment and interpersonal synergy, and assesses how they predict collective performance in a joint task. While the interactive alignment approach highlights imitative patterns between...... interlocutors, the synergy approach points to structural organization at the level of the interaction - such as complementary patterns straddling speech-turns and interlocutors. We develop a general, quantitative method to assess lexical, prosodic and speech/pause patterns related to the two approaches...... and their impact on collective performance in a corpus of task-oriented conversations. The results show statistical presence of patterns relevant for both approaches. However, synergetic aspects of dialog provide the best statistical predictors of collective performance and adding aspects of the alignment approach...

  7. Analyzing Dynamic Task-Based Applications on Hybrid Platforms: An Agile Scripting Approach

    OpenAIRE

    Garcia Pinto, Vinicius; Stanisic, Luka; Legrand, Arnaud; Mello Schnorr, Lucas; Thibault, Samuel; Danjean, Vincent

    2016-01-01

    In this paper, we present visual analysis techniques to evaluate the performance of HPC task-based applications on hybrid architectures. Our approach is based on composing modern data analysis tools (pjdump, R, ggplot2, plotly), enabling an agile and flexible scripting framework with minor development cost. We validate our proposal by analyzing traces from the full-fledged implementation of the Cholesky decomposition available in the MORSE library running on a hybrid (CPU/GPU) platform. The a...

  8. The use of cognitive cues for anticipatory strategies in a dynamic postural control task - validation of a novel approach to dual-task testing

    DEFF Research Database (Denmark)

    Læssøe, Uffe; Grarup, Bo; Bangshaab, Jette

    2016-01-01

    Introduction: Dual-task testing is relevant in the assessment of postural control. A combination of a primary (motor) and a secondary (distracting cognitive) tasks is most often used. It remains a challenge however, to standardize and monitor the cognitive task. In this study a new dual......-task testing approach with a facilitating, rather than distracting, cognitive component was evaluated.Methods: Thirty-one community-dwelling elderly and fifteen young people were tested with respect to their ability to use anticipatory postural control strategies. The motor task consisted of twenty...... two sessions. Conclusion: The dual-task test was sensitive enough to discriminate between elderly and young people. It revealed that the elderly did not utilize cognitive cues for their anticipatory postural control strategies as well as the young were able to. The test procedure was feasible...

  9. Using a binaural biomimetic array to identify bottom objects ensonified by echolocating dolphins

    Science.gov (United States)

    Heiweg, D.A.; Moore, P.W.; Martin, S.W.; Dankiewicz, L.A.

    2006-01-01

    The development of a unique dolphin biomimetic sonar produced data that were used to study signal processing methods for object identification. Echoes from four metallic objects proud on the bottom, and a substrate-only condition, were generated by bottlenose dolphins trained to ensonify the targets in very shallow water. Using the two-element ('binaural') receive array, object echo spectra were collected and submitted for identification to four neural network architectures. Identification accuracy was evaluated over two receive array configurations, and five signal processing schemes. The four neural networks included backpropagation, learning vector quantization, genetic learning and probabilistic network architectures. The processing schemes included four methods that capitalized on the binaural data, plus a monaural benchmark process. All the schemes resulted in above-chance identification accuracy when applied to learning vector quantization and backpropagation. Beam-forming or concatenation of spectra from both receive elements outperformed the monaural benchmark, with higher sensitivity and lower bias. Ultimately, best object identification performance was achieved by the learning vector quantization network supplied with beam-formed data. The advantages of multi-element signal processing for object identification are clearly demonstrated in this development of a first-ever dolphin biomimetic sonar. ?? 2006 IOP Publishing Ltd.

  10. A Combined Feedback and Noise Cancellation Algorithm for Binaural Hearing Aids

    Directory of Open Access Journals (Sweden)

    LEE, H.-W.

    2011-08-01

    Full Text Available This paper proposes an adaptive algorithm for the combined acoustic feedback and noise cancellation in the binaural hearing aids. The proposed algorithm is based on dual microphones for feedback cancellation and the beamforming method for noise cancellation. The coefficients of feedback canceller are updated after subtracting the speech signal from the input signal by dual microphones. And the noise canceller reduces the noise signal in the residual signal excluding the speech by the beamforming method. Firstly, the feedback canceller operates to cancel the feedback signal in the microphone signal, and then the noise canceller operates to reduce the noise in the residual signal. Also, to assure the stable convergence of binaural hearing aids in the training mode, the coefficients of the left hearing aid are firstly updated, then the coefficients of the right hearing aid are updated. In the normal mode, the feedback and the noise canceller are operated without updating coefficients except an unstable case. To verify performances of the proposed algorithm, we analyzed its convergence behavior and simulated for real speech. From the results of simulations, it was proved that we can advance 14.43dB SFR(speech-to-feedback ratio on average in the feedback canceller, 10.19dB SNR(speech-to-noise ratio improvement on average in the noise canceller, in the case of applying the proposed algorithm.

  11. A Heart for Interaction: Shared Physiological Dynamics and Behavioral Coordination in a Collective, Creative Construction Task

    DEFF Research Database (Denmark)

    Fusaroli, Riccardo; Stege Bjørndahl, Johanne; Roepstorff, Andreas;

    2016-01-01

    participants doing the same things) than in collective ones (involving participants taking turns and performing complementary actions). However, when contrasted against virtual pairs, collective trials display more stable shared HR dynamics suggesting that online social interaction plays an important role...

  12. Movement generation using dynamical systems: a humanoid robot performing a drumming task

    OpenAIRE

    Degallier, Sarah; Santos, Cristina; Righetti, Ludovic; Ijspeert, Auke

    2006-01-01

    The online generation of trajectories in humanoid robots remains a difficult problem. In this contribution, we present a system that allows the superposition, and the switch between, discrete and rhythmic movements. Our approach uses nonlinear dynamical systems for generating trajectories online and in real time. Our goal is to make use of attractor properties of dynamical systems in order to provide robustness against small perturbations and to enable online modulation of the trajector...

  13. Motor intensive anti-gravity training improves performance in dynamic balance related tasks in persons with Parkinson's disease

    DEFF Research Database (Denmark)

    Malling, Anne Sofie Bøgh; Jensen, Bente Rona

    2016-01-01

    Recent studies indicate that the effect of training on motor performance in persons with Parkinson's disease (PDP) is dependent on motor intensity. However, training of high motor intensity can be hard to apply in PDP due to e.g. bradykinesia, rigidity, tremor and postural instability. Therefore......, the aim was to study the effect of motor intensive training performed in a safe anti-gravity environment using lower-body positive pressure (LBPP) technology on performance during dynamic balance related tasks. Thirteen male PDP went through an 8-week control period followed by 8 weeks of motor intensive...... antigravity training. Seventeen healthy males constituted a control group (CON). Performance during a five repetition sit-to-stand test (STS; sagittal plane) and a dynamic postural balance test (DPB; transversal plane) was evaluated. Effect measures were completion time, functional rates of force development...

  14. Dynamic Effects of Self-Relevance and Task on the Neural Processing of Emotional Words in Context.

    Science.gov (United States)

    Fields, Eric C; Kuperberg, Gina R

    2015-01-01

    We used event-related potentials (ERPs) to examine the interactions between task, emotion, and contextual self-relevance on processing words in social vignettes. Participants read scenarios that were in either third person (other-relevant) or second person (self-relevant) and we recorded ERPs to a neutral, pleasant, or unpleasant critical word. In a previously reported study (Fields and Kuperberg, 2012) with these stimuli, participants were tasked with producing a third sentence continuing the scenario. We observed a larger LPC to emotional words than neutral words in both the self-relevant and other-relevant scenarios, but this effect was smaller in the self-relevant scenarios because the LPC was larger on the neutral words (i.e., a larger LPC to self-relevant than other-relevant neutral words). In the present work, participants simply answered comprehension questions that did not refer to the emotional aspects of the scenario. Here we observed quite a different pattern of interaction between self-relevance and emotion: the LPC was larger to emotional vs. neutral words in the self-relevant scenarios only, and there was no effect of self-relevance on neutral words. Taken together, these findings suggest that the LPC reflects a dynamic interaction between specific task demands, the emotional properties of a stimulus, and contextual self-relevance. We conclude by discussing implications and future directions for a functional theory of the emotional LPC.

  15. Keep it simple - A case study of model development in the context of the Dynamic Stocks and Flows (DSF) task

    Science.gov (United States)

    Halbrügge, Marc

    2010-12-01

    This paper describes the creation of a cognitive model submitted to the ‘Dynamic Stocks and Flows’ (DSF) modeling challenge. This challenge aims at comparing computational cognitive models for human behavior during an open ended control task. Participants in the modeling competition were provided with a simulation environment and training data for benchmarking their models while the actual specification of the competition task was withheld. To meet this challenge, the cognitive model described here was designed and optimized for generalizability. Only two simple assumptions about human problem solving were used to explain the empirical findings of the training data. In-depth analysis of the data set prior to the development of the model led to the dismissal of correlations or other parametric statistics as goodness-of-fit indicators. A new statistical measurement based on rank orders and sequence matching techniques is being proposed instead. This measurement, when being applied to the human sample, also identifies clusters of subjects that use different strategies for the task. The acceptability of the fits achieved by the model is verified using permutation tests.

  16. The role of spectral detail in the binaural transfer function on perceived externalization in a reverberant environment

    DEFF Research Database (Denmark)

    Hassager, Henrik Gert; Gran, Fredrik; Dau, Torsten

    2016-01-01

    , a quantitative model is proposed. The model includes an echo-suppression mechanism, a filterbank describing the frequency selectivity in the cochlea and a binaural stage that measures the deviations of the interaural level differences between the considered input and the unmodified input. These deviations...

  17. Task and context sensitive optimization of gripper design using dynamic grasp simulation

    DEFF Research Database (Denmark)

    Wolniakowski, Adam; Jørgensen, Jimmy Alison; Miatliuk, Konstantsin;

    2015-01-01

    In this work, we present a generic approach to optimize the design of a parametrized robot gripper including both gripper parameters and parameters of the finger geometry. We demonstrate our gripper optimization on a parallel jaw type gripper which we have parametrized in a 11 dimensional space. We...... furthermore present a parametrization of the grasping task and context, which is essential as input to the computation of gripper performance. We exemplify the feasibility of our approach by computing several optimized grippers on a real world industrial object in three different scenarios....

  18. Hip External Rotator Strength Is Associated With Better Dynamic Control of the Lower Extremity During Landing Tasks.

    Science.gov (United States)

    Malloy, Philip J; Morgan, Alexander M; Meinerz, Carolyn M; Geiser, Christopher F; Kipp, Kristof

    2016-01-01

    The purpose of this study was to determine the association between hip strength and lower extremity kinematics and kinetics during unanticipated single-leg landing and cutting tasks in collegiate female soccer players. Twenty-three National Collegiate Athletic Association division I female soccer players were recruited for strength testing and biomechanical analysis. Maximal isometric hip abduction and external rotation strength were measured using a hand-held dynamometer and expressed as muscle torque (force × femoral length) and normalized to body weight. Three-dimensional lower extremity kinematics and kinetics were assessed with motion analysis and force plates, and an inverse dynamics approach was used to calculate net internal joint moments that were normalized to body weight. Greater hip external rotator strength was significantly associated with greater peak hip external rotation moments (r = 0.47; p = 0.021), greater peak knee internal rotation moments (r = 0.41; p = 0.048), greater hip frontal plane excursion (r = 0.49; p = 0.017), and less knee transverse plane excursion (r = -0.56; p = 0.004) during unanticipated single-leg landing and cutting tasks. In addition, a statistical trend was detected between hip external rotator strength and peak hip frontal plane moments (r = 0.39; p = 0.06). The results suggest that females with greater hip external rotator strength demonstrate better dynamic control of the lower extremity during unanticipated single-leg landing and cutting tasks and provide further support for the link between hip strength and lower extremity landing mechanics. PMID:26110347

  19. The across frequency independence of equalization of interaural time delay in the equalization-cancellation model of binaural unmasking

    Science.gov (United States)

    Akeroyd, Michael A.

    2004-08-01

    The equalization stage in the equalization-cancellation model of binaural unmasking compensates for the interaural time delay (ITD) of a masking noise by introducing an opposite, internal delay [N. I. Durlach, in Foundations of Modern Auditory Theory, Vol. II., edited by J. V. Tobias (Academic, New York, 1972)]. Culling and Summerfield [J. Acoust. Soc. Am. 98, 785-797 (1995)] developed a multi-channel version of this model in which equalization was ``free'' to use the optimal delay in each channel. Two experiments were conducted to test if equalization was indeed free or if it was ``restricted'' to the same delay in all channels. One experiment measured binaural detection thresholds, using an adaptive procedure, for 1-, 5-, or 17-component tones against a broadband masking noise, in three binaural configurations (N0S180, N180S0, and N90S270). The thresholds for the 1-component stimuli were used to normalize the levels of each of the 5- and 17-component stimuli so that they were equally detectable. If equalization was restricted, then, for the 5- and 17-component stimuli, the N90S270 and N180S0 configurations would yield a greater threshold than the N0S180 configurations. No such difference was found. A subsequent experiment measured binaural detection thresholds, via psychometric functions, for a 2-component complex tone in the same three binaural configurations. Again, no differential effect of configuration was observed. An analytic model of the detection of a complex tone showed that the results were more consistent with free equalization than restricted equalization, although the size of the differences was found to depend on the shape of the psychometric function for detection.

  20. Motor intensive anti-gravity training improves performance in dynamic balance related tasks in persons with Parkinson's disease.

    Science.gov (United States)

    Malling, Anne Sofie B; Jensen, Bente R

    2016-01-01

    Recent studies indicate that the effect of training on motor performance in persons with Parkinson's disease (PDP) is dependent on motor intensity. However, training of high motor intensity can be hard to apply in PDP due to e.g. bradykinesia, rigidity, tremor and postural instability. Therefore, the aim was to study the effect of motor intensive training performed in a safe anti-gravity environment using lower-body positive pressure (LBPP) technology on performance during dynamic balance related tasks. Thirteen male PDP went through an 8-week control period followed by 8 weeks of motor intensive antigravity training. Seventeen healthy males constituted a control group (CON). Performance during a five repetition sit-to-stand test (STS; sagittal plane) and a dynamic postural balance test (DPB; transversal plane) was evaluated. Effect measures were completion time, functional rates of force development, directional changes and force variance. STS completion time improved by 24% to the level of CON which was explained by shorter sitting-time and standing-time and larger numeric rate of force change during lowering to the chair, indicating faster vertical directional change and improved relaxation. DPB completion time tended to improve and was accompanied by improvements of functional medial and lateral rates of force development and higher vertical force variance during DPB. Our results suggest that the performance improvements may relate to improved inter-limb coordination. It is concluded that 8 weeks of motor intensive training in a safe LBPP environment improved performance during dynamic balance related tasks in PDP. PMID:26444077

  1. Dynamic simulation of task constrained of a rigid-flexible manipulator

    Directory of Open Access Journals (Sweden)

    Atef A. Ata

    2008-11-01

    Full Text Available A rigid-flexible manipulator may be assigned tasks in a moving environment where the winds or vibrations affect the position and/or orientation of surface of operation. Consequently, losses of the contact and perhaps degradation of the performance may occur as references are changed. When the environment is moving, knowledge of the angle ? between the contact surface and the horizontal is required at every instant. In this paper, different profiles for the time varying angle ? are proposed to investigate the effect of this change into the contact force and the joint torques of a rigid-flexible manipulator. The coefficients of the equation of the proposed rotating surface are changing with time to determine the new X and Y coordinates of the moving surface as the surface rotates.

  2. A robust certification service for highly dynamic MANET in emergency tasks

    DEFF Research Database (Denmark)

    Ge, M; Lam, K Y; Gollmann, Dieter;

    2009-01-01

    In emergency tasks, cross-agency operations being carried out in disaster-hit areas require some supporting communication system for command and control. Mobile Ad hoc Network (MANET) is a very suitable way to meet such communication requirements since it can function without any pre...... mechanisms. In this paper, we tackle issues critical to asymmetric key management in MANET, which almost invariably serves as a basis of security services in a network environment. To address the deficiencies of existing key management schemes, we propose the concept of mission-specific certificate to manage...... public keys in our scenario. For issuance and/or revocation of mission-specific certificate, a Mission-specific Certificate Authority (MCA), which consists of a collection of server nodes to operate the threshold cryptographic scheme, is proposed. Furthermore, to cater for the occurrence of network...

  3. Electrophysiological and psychophysical asymmetries in sensitivity to interaural correlation gaps and implications for binaural integration time.

    Science.gov (United States)

    Lüddemann, Helge; Kollmeier, Birger; Riedel, Helmut

    2016-02-01

    Brief deviations of interaural correlation (IAC) can provide valuable cues for detection, segregation and localization of acoustic signals. This study investigated the processing of such "binaural gaps" in continuously running noise (100-2000 Hz), in comparison to silent "monaural gaps", by measuring late auditory evoked potentials (LAEPs) and perceptual thresholds with novel, iteratively optimized stimuli. Mean perceptual binaural gap duration thresholds exhibited a major asymmetry: they were substantially shorter for uncorrelated gaps in correlated and anticorrelated reference noise (1.75 ms and 4.1 ms) than for correlated and anticorrelated gaps in uncorrelated reference noise (26.5 ms and 39.0 ms). The thresholds also showed a minor asymmetry: they were shorter in the positive than in the negative IAC range. The mean behavioral threshold for monaural gaps was 5.5 ms. For all five gap types, the amplitude of LAEP components N1 and P2 increased linearly with the logarithm of gap duration. While perceptual and electrophysiological thresholds matched for monaural gaps, LAEP thresholds were about twice as long as perceptual thresholds for uncorrelated gaps, but half as long for correlated and anticorrelated gaps. Nevertheless, LAEP thresholds showed the same asymmetries as perceptual thresholds. For gap durations below 30 ms, LAEPs were dominated by the processing of the leading edge of a gap. For longer gap durations, in contrast, both the leading and the lagging edge of a gap contributed to the evoked response. Formulae for the equivalent rectangular duration (ERD) of the binaural system's temporal window were derived for three common window shapes. The psychophysical ERD was 68 ms for diotic and about 40 ms for anti- and uncorrelated noise. After a nonlinear Z-transform of the stimulus IAC prior to temporal integration, ERDs were about 10 ms for reference correlations of ±1 and 80 ms for uncorrelated reference. Hence, a physiologically motivated

  4. Selecting a dynamic simulation modeling method for health care delivery research-part 2: report of the ISPOR Dynamic Simulation Modeling Emerging Good Practices Task Force.

    Science.gov (United States)

    Marshall, Deborah A; Burgos-Liz, Lina; IJzerman, Maarten J; Crown, William; Padula, William V; Wong, Peter K; Pasupathy, Kalyan S; Higashi, Mitchell K; Osgood, Nathaniel D

    2015-03-01

    In a previous report, the ISPOR Task Force on Dynamic Simulation Modeling Applications in Health Care Delivery Research Emerging Good Practices introduced the fundamentals of dynamic simulation modeling and identified the types of health care delivery problems for which dynamic simulation modeling can be used more effectively than other modeling methods. The hierarchical relationship between the health care delivery system, providers, patients, and other stakeholders exhibits a level of complexity that ought to be captured using dynamic simulation modeling methods. As a tool to help researchers decide whether dynamic simulation modeling is an appropriate method for modeling the effects of an intervention on a health care system, we presented the System, Interactions, Multilevel, Understanding, Loops, Agents, Time, Emergence (SIMULATE) checklist consisting of eight elements. This report builds on the previous work, systematically comparing each of the three most commonly used dynamic simulation modeling methods-system dynamics, discrete-event simulation, and agent-based modeling. We review criteria for selecting the most suitable method depending on 1) the purpose-type of problem and research questions being investigated, 2) the object-scope of the model, and 3) the method to model the object to achieve the purpose. Finally, we provide guidance for emerging good practices for dynamic simulation modeling in the health sector, covering all aspects, from the engagement of decision makers in the model design through model maintenance and upkeep. We conclude by providing some recommendations about the application of these methods to add value to informed decision making, with an emphasis on stakeholder engagement, starting with the problem definition. Finally, we identify areas in which further methodological development will likely occur given the growing "volume, velocity and variety" and availability of "big data" to provide empirical evidence and techniques

  5. Temporal Dynamics of Task Switching and Abstract-Concept Learning in Pigeons

    Directory of Open Access Journals (Sweden)

    Thomas Alexander Daniel

    2015-09-01

    Full Text Available The current study examined whether pigeons could learn to use abstract concepts as the basis for conditionally switching behavior as a function of time. Using a mid-session reversal task, experienced pigeons were trained to switch from matching-to-sample (MTS to non-matching-to-sample (NMTS conditional discriminations within a session. One group had prior training with MTS, while the other had prior training with NMTS. Over training, stimulus set size was progressively doubled from 3 to 6 to 12 stimuli to promote abstract concept development. Prior experience had an effect on the initial learning at each of the set sizes but by the end of training there were no group differences, as both groups showed similar within-session linear matching functions. After acquiring the 12-item set, abstract-concept learning was tested by placing novel stimuli at the beginning and end of a test session. Prior matching and non-matching experience affected transfer behavior. The matching experienced group transferred to novel stimuli in both the matching and non-matching portion of the sessions using a matching rule. The non-matching experienced group transferred to novel stimuli in both portions of the session using a non-matching rule. The representations used as the basis for mid-session reversal of the conditional discrimination behaviors and subsequent transfer behavior appears to have different temporal sources. The implications for the flexibility and organization of complex behaviors are considered.

  6. Brain-wave Dynamics Related to Cognitive Tasks and Neurofeedback Information Flow

    Science.gov (United States)

    Pop-Jordanova, Nada; Pop-Jordanov, Jordan; Dimitrovski, Darko; Markovska, Natasa

    2003-08-01

    Synchronization of oscillating neuronal discharges has been recently correlated to the moment of perception and the ensuing motor response, with transition between these two cognitive acts "through cellular mechanisms that remain to be established"[1]. Last year, using genetic strategies, it was found that the switching off persistent electric activity in the brain blocks memory recall [2]. On the other hand, analyzing mental-neural information flow, the nobelist Eccles has formulated a fundamental hypotheses that mental events may change the probability of quantum vesicular emissions of transmitters analogously to probability functions of quantum mechanics [3]. Applying the advanced quantum modeling to molecular rotational states exposed to electric activity in brain cells, we found that the probability of transitions does not depend on the field amplitude, suggesting the electric field frequency as the possible information-bearing physical quantity [4]. In this paper, an attempt is made to inter-correlate the above results on frequency aspects of neural transitions induced by cognitive tasks. Furthermore, considering the consecutive steps of mental-neural information flow during the biofeedback training to normalize EEG frequencies, the rationales for neurofeedback efficiency have been deduced.

  7. Temporal dynamics of task switching and abstract-concept learning in pigeons.

    Science.gov (United States)

    Daniel, Thomas A; Cook, Robert G; Katz, Jeffrey S

    2015-01-01

    The current study examined whether pigeons could learn to use abstract concepts as the basis for conditionally switching behavior as a function of time. Using a mid-session reversal task, experienced pigeons were trained to switch from matching-to-sample (MTS) to non-matching-to-sample (NMTS) conditional discriminations within a session. One group had prior training with MTS, while the other had prior training with NMTS. Over training, stimulus set size was progressively doubled from 3 to 6 to 12 stimuli to promote abstract concept development. Prior experience had an effect on the initial learning at each of the set sizes but by the end of training there were no group differences, as both groups showed similar within-session linear matching functions. After acquiring the 12-item set, abstract-concept learning was tested by placing novel stimuli at the beginning and end of a test session. Prior matching and non-matching experience affected transfer behavior. The matching experienced group transferred to novel stimuli in both the matching and non-matching portion of the sessions using a matching rule. The non-matching experienced group transferred to novel stimuli in both portions of the session using a non-matching rule. The representations used as the basis for mid-session reversal of the conditional discrimination behaviors and subsequent transfer behavior appears to have different temporal sources. The implications for the flexibility and organization of complex behaviors are considered.

  8. Lateral reflections are favorable in concert halls due to binaural loudness.

    Science.gov (United States)

    Lokki, Tapio; Pätynen, Jukka

    2011-11-01

    A recent study on perceptual difference in simulated concert halls showed that a concert hall renders stronger sound with more bass when the temporal envelope of a signal is preserved in the reflections [Lokki et al., J. Acoust. Soc. Am. 129, EL223-EL228 (2011)]. In the same study the lateral reflections were shown to contribute to the perceived envelopment and openness. Moreover, the listening test results suggest that lateral reflections contribute to perception of sound source distance. Here, it is shown that lateral reflections are beneficial due to their increasing effect on binaural loudness-the phenomenon known well in psychoacoustics, but not in architectural acoustics. The reflections from the side are amplified more than median plane reflections, in particular at high frequencies, due to the shape of the human head. PMID:22088039

  9. Technical and perceptual issues on head-related transfer functions sets for use in binaural synthesis

    DEFF Research Database (Denmark)

    Toledo, Daniela

    Head-related transfer functions (HRTFs) are the filters used in binaural synthesis that provide the necessary cues to localize virtual sound sources in virtual 3D space. HRTFs are recorded at the ears of either humans or dummy-heads and are usually implemented as non-individual filters. The success...... the spectral features that cue sound localization in the mid-sagittal plane. Listening tests were conducted from which groups of individual and non-individual HRTFs that evoked the same direction were obtained. Analysis of these HRTFs suggested that the relevant spectral cues covered a broad range...... of frequencies. Parameters describing the spectral features were computed. Those parameters were seen to span ranges of values and frequencies and still evoke the same directions. These ranges seemed to be individual, ruling out the possibility of a unique set of non-individual HRTFs that overperforms current...

  10. Interaction learning for dynamic movement primitives used in cooperative robotic tasks

    DEFF Research Database (Denmark)

    Kulvicius, Tomas; Biehl, Martin; Aein, Mohamad Javad;

    2013-01-01

    Abstract Since several years dynamic movement primitives (DMPs) are more and more getting into the center of interest for flexible movement control in robotics. In this study we introduce sensory feedback together with a predictive learning mechanism which allows tightly coupled dual-agent system...... to cooperate. Simulations as well as real-robot experiments are shown. Interestingly, all these mechanisms are entirely based on low level interactions without any planning or cognitive component.......Abstract Since several years dynamic movement primitives (DMPs) are more and more getting into the center of interest for flexible movement control in robotics. In this study we introduce sensory feedback together with a predictive learning mechanism which allows tightly coupled dual-agent systems...... to learn an adaptive, sensor-driven interaction based on DMPs. The coupled conventional (no-sensors, no learning) DMP-system automatically equilibrates and can still be solved analytically allowing us to derive conditions for stability. When adding adaptive sensor control we can show that both agents learn...

  11. Hawaii energy strategy project 2: Fossil energy review. Task 1: World and regional fossil energy dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Breazeale, K. [ed.; Isaak, D.T.; Yamaguchi, N.; Fridley, D.; Johnson, C.; Long, S.

    1993-12-01

    This report in the Hawaii Energy Strategy Project examines world and regional fossil energy dynamics. The topics of the report include fossil energy characteristics, the world oil industry including reserves, production, consumption, exporters, importers, refining, products and their uses, history and trends in the global oil market and the Asia-Pacific market; world gas industry including reserves, production, consumption, exporters, importers, processing, gas-based products, international gas market and the emerging Asia-Pacific gas market; the world coal industry including reserves, classification and quality, utilization, transportation, pricing, world coal market, Asia-Pacific coal outlook, trends in Europe and the Americas; and environmental trends affecting fossil fuels. 132 figs., 46 tabs.

  12. Understanding and Mastering Dynamics in Computing Grids Processing Moldable Tasks with User-Level Overlay

    CERN Document Server

    Moscicki, Jakub Tomasz

    Scientic communities are using a growing number of distributed systems, from lo- cal batch systems, community-specic services and supercomputers to general-purpose, global grid infrastructures. Increasing the research capabilities for science is the raison d'^etre of such infrastructures which provide access to diversied computational, storage and data resources at large scales. Grids are rather chaotic, highly heterogeneous, de- centralized systems where unpredictable workloads, component failures and variability of execution environments are commonplace. Understanding and mastering the hetero- geneity and dynamics of such distributed systems is prohibitive for end users if they are not supported by appropriate methods and tools. The time cost to learn and use the interfaces and idiosyncrasies of dierent distributed environments is another challenge. Obtaining more reliable application execution times and boosting parallel speedup are important to increase the research capabilities of scientic communities. L...

  13. Using Dynamic Multi-Task Non-Negative Matrix Factorization to Detect the Evolution of User Preferences in Collaborative Filtering.

    Science.gov (United States)

    Ju, Bin; Qian, Yuntao; Ye, Minchao; Ni, Rong; Zhu, Chenxi

    2015-01-01

    Predicting what items will be selected by a target user in the future is an important function for recommendation systems. Matrix factorization techniques have been shown to achieve good performance on temporal rating-type data, but little is known about temporal item selection data. In this paper, we developed a unified model that combines Multi-task Non-negative Matrix Factorization and Linear Dynamical Systems to capture the evolution of user preferences. Specifically, user and item features are projected into latent factor space by factoring co-occurrence matrices into a common basis item-factor matrix and multiple factor-user matrices. Moreover, we represented both within and between relationships of multiple factor-user matrices using a state transition matrix to capture the changes in user preferences over time. The experiments show that our proposed algorithm outperforms the other algorithms on two real datasets, which were extracted from Netflix movies and Last.fm music. Furthermore, our model provides a novel dynamic topic model for tracking the evolution of the behavior of a user over time.

  14. Using Dynamic Multi-Task Non-Negative Matrix Factorization to Detect the Evolution of User Preferences in Collaborative Filtering.

    Directory of Open Access Journals (Sweden)

    Bin Ju

    Full Text Available Predicting what items will be selected by a target user in the future is an important function for recommendation systems. Matrix factorization techniques have been shown to achieve good performance on temporal rating-type data, but little is known about temporal item selection data. In this paper, we developed a unified model that combines Multi-task Non-negative Matrix Factorization and Linear Dynamical Systems to capture the evolution of user preferences. Specifically, user and item features are projected into latent factor space by factoring co-occurrence matrices into a common basis item-factor matrix and multiple factor-user matrices. Moreover, we represented both within and between relationships of multiple factor-user matrices using a state transition matrix to capture the changes in user preferences over time. The experiments show that our proposed algorithm outperforms the other algorithms on two real datasets, which were extracted from Netflix movies and Last.fm music. Furthermore, our model provides a novel dynamic topic model for tracking the evolution of the behavior of a user over time.

  15. Dynamic causal modelling of EEG and fMRI to characterize network architectures in a simple motor task.

    Science.gov (United States)

    Bönstrup, Marlene; Schulz, Robert; Feldheim, Jan; Hummel, Friedhelm C; Gerloff, Christian

    2016-01-01

    Dynamic causal modelling (DCM) has extended the understanding of brain network dynamics in a variety of functional systems. In the motor system, DCM studies based on functional magnetic resonance imaging (fMRI) or on magneto-/electroencephalography (M/EEG) have demonstrated movement-related causal information flow from secondary to primary motor areas and have provided evidence for nonlinear cross-frequency interactions among motor areas. The present study sought to investigate to what extent fMRI- and EEG-based DCM might provide complementary and synergistic insights into neuronal network dynamics. Both modalities share principal similarities in the formulation of the DCM. Thus, we hypothesized that DCM based on induced EEG responses (DCM-IR) and on fMRI would reveal congruent task-dependent network dynamics. Brain electrical (63-channel surface EEG) and Blood Oxygenation Level Dependent (BOLD) signals were recorded in separate sessions from 14 healthy participants performing simple isometric right and left hand grips. DCM-IR and DCM-fMRI were used to estimate coupling parameters modulated by right and left hand grips within a core motor network of six regions comprising bilateral primary motor cortex (M1), ventral premotor cortex (PMv) and supplementary motor area (SMA). We found that DCM-fMRI and DCM-IR similarly revealed significant grip-related increases in facilitatory coupling between SMA and M1 contralateral to the active hand. A grip-dependent interhemispheric reciprocal inhibition between M1 bilaterally was only revealed by DCM-fMRI but not by DCM-IR. Frequency-resolved coupling analysis showed that the information flow from contralateral SMA to M1 was predominantly a linear alpha-to-alpha (9-13Hz) interaction. We also detected some cross-frequency coupling from SMA to contralateral M1, i.e., between lower beta (14-21Hz) at the SMA and higher beta (22-30Hz) at M1 during right hand grip and between alpha (9-13Hz) at SMA and lower beta (14-21Hz) at M1

  16. Benefits to Speech Perception in Noise From the Binaural Integration of Electric and Acoustic Signals in Simulated Unilateral Deafness

    OpenAIRE

    Ma, Ning; Morris, Saffron; Kitterick, Pádraig Thomas

    2015-01-01

    Objectives: This study used vocoder simulations with normal-hearing (NH) listeners to (1) measure their ability to integrate speech information from an NH ear and a simulated cochlear implant (CI), and (2) investigate whether binaural integration is disrupted by a mismatch in the delivery of spectral information between the ears arising from a misalignment in the mapping of frequency to place. Design: Eight NH volunteers participated in the study and listened to sentences embedded in backgrou...

  17. The cardiac cycle time effect revisited: Temporal dynamics of the central-vagal modulation of heart rate in human reaction time tasks.

    NARCIS (Netherlands)

    R.J.M. Somsen; J.R. Jennings; M.W. van der Molen

    2004-01-01

    Lacey and Lacey (1974) suggested that during reaction time tasks higher brain centers dynamically adjust efferent vagal nerve pulses to the sino-atrial node of the heart, inducing phase-dependent heart rate changes. Since then, animal and human neuro-physiological results have provided evidence for

  18. NOVEL RULE-BASED STATIC AND DYNAMIC FEATURE EXTRACTION FROM FIGURE COPYING TASKS FOR THE DETECTION OF VISUO-SPATIAL NEGLECT

    NARCIS (Netherlands)

    Guest, R.M.; Fairhurst, M.C.; Potter, J.M.; Donelly, N.

    2004-01-01

    A series of static rule-based assessment criteria and dynamic constructional features are defined and used to analyse the hand-drawn responses from a geometric figure copying task. Assessment subjectivity is removed by the algorithmic definition of analysis criteria and test diagnostic sensitivity t

  19. 基于评价函数的动态协同任务调度算法%Evaluation function-based dynamic collaboration task scheduling algorithm

    Institute of Scientific and Technical Information of China (English)

    王璇; 颜景龙

    2011-01-01

    As the problems that resources change dynamically and tasks access in complex grid environment,a dynamic collaboration task scheduling based on the evaluation function was proposed.This algorithm solves the task cooperation scheduling in dynamic grid by using evaluation function of tasks and collaborators,which vary with time.Compared with distributed cooperation scheduling algorithm based on contract net,theoretical analysis and experimental results show that the algorithm is effective to reduce the system overhead and improve the resource allocation.%针对复杂网格环境中节点资源动态变化及大量任务协作访问的问题,提出一种基于评价函数的动态协作任务调度算法.该算法通过为网格中的协作任务与协作成员建立随时间变化的任务评价函数和协作成员评价函数,实现动态网格环境中的任务协同调度.理论分析与仿真实验表明:与基于合同网的分布式合作调度算法相比,本算法能够减小系统开销,提高资源分配效率.

  20. Studies on Bilateral Cochlear Implants at the University of Wisconsin’s Binaural Hearing and Speech Lab

    OpenAIRE

    Litovsky, Ruth Y.; Goupell, Matthew J.; Godar, Shelly; Grieco-Calub, Tina; Jones, Gary L.; Garadat, Soha N.; Agrawal, Smita; Kan, Alan; Todd, Ann; Hess, Christi; Misurelli, Sara

    2012-01-01

    This report highlights research projects relevant to binaural and spatial hearing in adults and children. In the past decade we have made progress in understanding the impact of bilateral cochlear implants (BiCIs) on performance in adults and children. However, BiCI users typically do not perform as well as normal hearing (NH) listeners. In this paper we describe the benefits from BiCIs compared with a single CI, focusing on measures of spatial hearing and speech understanding in noise. We hi...

  1. Dual-microphone and binaural noise reduction techniques for improved speech intelligibility by hearing aid users

    Science.gov (United States)

    Yousefian Jazi, Nima

    Spatial filtering and directional discrimination has been shown to be an effective pre-processing approach for noise reduction in microphone array systems. In dual-microphone hearing aids, fixed and adaptive beamforming techniques are the most common solutions for enhancing the desired speech and rejecting unwanted signals captured by the microphones. In fact, beamformers are widely utilized in systems where spatial properties of target source (usually in front of the listener) is assumed to be known. In this dissertation, some dual-microphone coherence-based speech enhancement techniques applicable to hearing aids are proposed. All proposed algorithms operate in the frequency domain and (like traditional beamforming techniques) are purely based on the spatial properties of the desired speech source and does not require any knowledge of noise statistics for calculating the noise reduction filter. This benefit gives our algorithms the ability to address adverse noise conditions, such as situations where interfering talker(s) speaks simultaneously with the target speaker. In such cases, the (adaptive) beamformers lose their effectiveness in suppressing interference, since the noise channel (reference) cannot be built and updated accordingly. This difference is the main advantage of the proposed techniques in the dissertation over traditional adaptive beamformers. Furthermore, since the suggested algorithms are independent of noise estimation, they offer significant improvement in scenarios that the power level of interfering sources are much more than that of target speech. The dissertation also shows the premise behind the proposed algorithms can be extended and employed to binaural hearing aids. The main purpose of the investigated techniques is to enhance the intelligibility level of speech, measured through subjective listening tests with normal hearing and cochlear implant listeners. However, the improvement in quality of the output speech achieved by the

  2. Functional segregation of monaural and binaural selectivity in the pallid bat auditory cortex.

    Science.gov (United States)

    Razak, Khaleel A

    2016-07-01

    Different fields of the auditory cortex can be distinguished by the extent and level tolerance of spatial selectivity. The mechanisms underlying the range of spatial tuning properties observed across cortical fields are unclear. Here, this issue was addressed in the pallid bat because its auditory cortex contains two segregated regions of response selectivity that serve two different behaviors: echolocation for obstacle avoidance and localization of prey-generated noise. This provides the unique opportunity to examine mechanisms of spatial properties in two functionally distinct regions. Previous studies have shown that spatial selectivity of neurons in the region selective for noise (noise-selective region, NSR) is level tolerant and shaped by interaural level difference (ILD) selectivity. In contrast, spatial selectivity of neurons in the echolocation region ('FM sweep-selective region' or FMSR) is strongly level dependent with many neurons responding to multiple distinct spatial locations for louder sounds. To determine the mechanisms underlying such level dependence, frequency, azimuth, rate-level responses and ILD selectivity were measured from the same FMSR neurons. The majority (∼75%) of FMSR neurons were monaural (ILD insensitive). Azimuth tuning curves expanded or split into multiple peaks with increasing sound level in a manner that was predicted by the rate-level response of neurons. These data suggest that azimuth selectivity of FMSR neurons depends more on monaural ear directionality and rate-level responses. The pallid bat cortex utilizes segregated monaural and binaural regions to process echoes and prey-generated noise. Together the pallid bat FMSR/NSR data provide mechanistic explanations for a broad range of spatial tuning properties seen across species. PMID:27233917

  3. Modality-specific spectral dynamics in response to visual and tactile sequential shape information processing tasks: An MEG study using multivariate pattern classification analysis.

    Science.gov (United States)

    Gohel, Bakul; Lee, Peter; Jeong, Yong

    2016-08-01

    Brain regions that respond to more than one sensory modality are characterized as multisensory regions. Studies on the processing of shape or object information have revealed recruitment of the lateral occipital cortex, posterior parietal cortex, and other regions regardless of input sensory modalities. However, it remains unknown whether such regions show similar (modality-invariant) or different (modality-specific) neural oscillatory dynamics, as recorded using magnetoencephalography (MEG), in response to identical shape information processing tasks delivered to different sensory modalities. Modality-invariant or modality-specific neural oscillatory dynamics indirectly suggest modality-independent or modality-dependent participation of particular brain regions, respectively. Therefore, this study investigated the modality-specificity of neural oscillatory dynamics in the form of spectral power modulation patterns in response to visual and tactile sequential shape-processing tasks that are well-matched in terms of speed and content between the sensory modalities. Task-related changes in spectral power modulation and differences in spectral power modulation between sensory modalities were investigated at source-space (voxel) level, using a multivariate pattern classification (MVPC) approach. Additionally, whole analyses were extended from the voxel level to the independent-component level to take account of signal leakage effects caused by inverse solution. The modality-specific spectral dynamics in multisensory and higher-order brain regions, such as the lateral occipital cortex, posterior parietal cortex, inferior temporal cortex, and other brain regions, showed task-related modulation in response to both sensory modalities. This suggests modality-dependency of such brain regions on the input sensory modality for sequential shape-information processing. PMID:27134037

  4. Modality-specific spectral dynamics in response to visual and tactile sequential shape information processing tasks: An MEG study using multivariate pattern classification analysis.

    Science.gov (United States)

    Gohel, Bakul; Lee, Peter; Jeong, Yong

    2016-08-01

    Brain regions that respond to more than one sensory modality are characterized as multisensory regions. Studies on the processing of shape or object information have revealed recruitment of the lateral occipital cortex, posterior parietal cortex, and other regions regardless of input sensory modalities. However, it remains unknown whether such regions show similar (modality-invariant) or different (modality-specific) neural oscillatory dynamics, as recorded using magnetoencephalography (MEG), in response to identical shape information processing tasks delivered to different sensory modalities. Modality-invariant or modality-specific neural oscillatory dynamics indirectly suggest modality-independent or modality-dependent participation of particular brain regions, respectively. Therefore, this study investigated the modality-specificity of neural oscillatory dynamics in the form of spectral power modulation patterns in response to visual and tactile sequential shape-processing tasks that are well-matched in terms of speed and content between the sensory modalities. Task-related changes in spectral power modulation and differences in spectral power modulation between sensory modalities were investigated at source-space (voxel) level, using a multivariate pattern classification (MVPC) approach. Additionally, whole analyses were extended from the voxel level to the independent-component level to take account of signal leakage effects caused by inverse solution. The modality-specific spectral dynamics in multisensory and higher-order brain regions, such as the lateral occipital cortex, posterior parietal cortex, inferior temporal cortex, and other brain regions, showed task-related modulation in response to both sensory modalities. This suggests modality-dependency of such brain regions on the input sensory modality for sequential shape-information processing.

  5. Predicting binaural speech intelligibility using the signal-to-noise ratio in the envelope power spectrum domain.

    Science.gov (United States)

    Chabot-Leclerc, Alexandre; MacDonald, Ewen N; Dau, Torsten

    2016-07-01

    This study proposes a binaural extension to the multi-resolution speech-based envelope power spectrum model (mr-sEPSM) [Jørgensen, Ewert, and Dau (2013). J. Acoust. Soc. Am. 134, 436-446]. It consists of a combination of better-ear (BE) and binaural unmasking processes, implemented as two monaural realizations of the mr-sEPSM combined with a short-term equalization-cancellation process, and uses the signal-to-noise ratio in the envelope domain (SNRenv) as the decision metric. The model requires only two parameters to be fitted per speech material and does not require an explicit frequency weighting. The model was validated against three data sets from the literature, which covered the following effects: the number of maskers, the masker types [speech-shaped noise (SSN), speech-modulated SSN, babble, and reversed speech], the masker(s) azimuths, reverberation on the target and masker, and the interaural time difference of the target and masker. The Pearson correlation coefficient between the simulated speech reception thresholds and the data across all experiments was 0.91. A model version that considered only BE processing performed similarly (correlation coefficient of 0.86) to the complete model, suggesting that BE processing could be considered sufficient to predict intelligibility in most realistic conditions. PMID:27475146

  6. Scheduling PVM Tasks

    Institute of Scientific and Technical Information of China (English)

    鞠九滨; 王勇; 等

    1997-01-01

    This paper describes a PVM task scheduler designed and implemented by the authors.The scheduler supports selecting idle workstations,scheduling pool tasks and dynamically produced subtasks.It can improve resource utilization,reduce job response time and simplify programming.

  7. Windowed correlation: a suitable tool for providing dynamic fMRI-based functional connectivity neurofeedback on task difficulty.

    Directory of Open Access Journals (Sweden)

    Anna Zilverstand

    Full Text Available The goal of neurofeedback training is to provide participants with relevant information on their ongoing brain processes in order to enable them to change these processes in a meaningful way. Under the assumption of an intrinsic brain-behavior link, neurofeedback can be a tool to guide a participant towards a desired behavioral state, such as a healthier state in the case of patients. Current research in clinical neuroscience regarding the most robust indicators of pathological brain processes in psychiatric and neurological disorders indicates that fMRI-based functional connectivity measures may be among the most important biomarkers of disease. The present study therefore investigated the general potential of providing fMRI neurofeedback based on functional correlations, computed from short-window time course data at the level of single task periods. The ability to detect subtle changes in task performance with block-wise functional connectivity measures was evaluated based on imaging data from healthy participants performing a simple motor task, which was systematically varied along two task dimensions representing two different aspects of task difficulty. The results demonstrate that fMRI-based functional connectivity measures may provide a better indicator for an increase in overall (motor task difficulty than activation level-based measures. Windowed functional correlations thus seem to provide relevant and unique information regarding ongoing brain processes, which is not captured equally well by standard activation level-based neurofeedback measures. Functional connectivity markers, therefore, may indeed provide a valuable tool to enhance and monitor learning within an fMRI neurofeedback setup.

  8. Interferência binaural no processo de seleção e adaptação de próteses auditivas: revisão sistemática

    OpenAIRE

    Milena Manoel Azevedo; Ana Valéria de Almeida Vaucher; Mariana Teixeira Duarte; Eliara Pinto Vieira Biaggio; Maristela Julio Costa

    2013-01-01

    O tema deste estudo é a interferência binaural e tem como objetivo descrever, por meio de revisão teórica, o fenômeno caracterizado por interferência binaural. Será realizada revisão sistemática por meio de pesquisa nas bases de dados LILACS, MEDLINE, PUBMED e SCIELO. O fenômeno interferência binaural é uma realidade relatada na literatura, que precisa ser investigado. Pode se confirmar por testes específicos de processamento auditivo, o mais descrito foi o dicótico de dígitos.

  9. Auto-adaptative Robot-aided Therapy based in 3D Virtual Tasks controlled by a Supervised and Dynamic Neuro-Fuzzy System

    Directory of Open Access Journals (Sweden)

    Luis Daniel Lledó

    2015-03-01

    Full Text Available This paper presents an application formed by a classification method based on the architecture of ART neural network (Adaptive Resonance Theory and the Fuzzy Set Theory to classify physiological reactions in order to automatically and dynamically adapt a robot-assisted rehabilitation therapy to the patient needs, using a three-dimensional task in a virtual reality system. Firstly, the mathematical and structural model of the neuro-fuzzy classification method is described together with the signal and training data acquisition. Then, the virtual designed task with physics behavior and its development procedure are explained. Finally, the general architecture of the experimentation for the auto-adaptive therapy is presented using the classification method with the virtual reality exercise.

  10. Neural-network-based two-loop control of robotic manipulators including actuator dynamics in task space

    Institute of Scientific and Technical Information of China (English)

    Liangyong WANG; Tianyou CHAI; Zheng FANG

    2009-01-01

    A neural-network-based motion controller in task space is presented in this paper. The proposed controller is addressed as a two-loop cascade control scheme. The outer loop is given by kinematic control in the task space. It provides a joint velocity reference signal to the inner one. The inner loop implements a velocity servo loop at the robot joint level. A radial basis function network (RBFN) is integrated with proportional-integral (PI) control to construct a velocity tracking control scheme for the inner loop. Finally, a prototype technology based control system is designed for a robotic manipulator. The proposed control scheme is applied to the robotic manipulator. Experimental results confirm the validity of the proposed control scheme by comparing it with other control strategies.

  11. New evidence for strategic differences between static and dynamic search tasks: An individual observer analysis of eye movements

    Directory of Open Access Journals (Sweden)

    Christopher eDickinson

    2013-01-01

    Full Text Available Two experiments are reported that further explore the processes underlying dynamic search. In Experiment 1, observers’ oculomotor behavior was monitored while they searched for a randomly oriented T among oriented L distractors under static and dynamic viewing conditions. Despite similar search slopes, eye movements were less frequent and more spatially constrained under dynamic viewing relative to static, with misses also increasing more with target eccentricity in the dynamic condition. These patterns suggest that dynamic search involves a form of sit-and-wait strategy in which search is restricted to a small group of items surrounding fixation. To evaluate this interpretation, we developed a computational model of a sit-and-wait process hypothesized to underlie dynamic search. In Experiment 2 we tested this model by varying fixation position in the display and found that display positions optimized for a sit-and-wait strategy resulted in higher d' values relative to a less optimal location. We conclude that different strategies, and therefore underlying processes, are used to search static and dynamic displays.

  12. Developing a dynamic geometry task platform for accessing students' perceptions of geometric properties through analysis of example spaces

    OpenAIRE

    Lee, Man-sang, Arthur; 李文生

    2015-01-01

    Geometry learning at the junior secondary level should focus on the connection between students’ intuitive, spatial thinking and formal, deductive reasoning. It is crucial for students at this stage to develop abstract concepts based on knowledge of and reasoning with geometric properties. Dynamic geometry tools are promising resources in classroom teaching for enriching students’ experience in geometry. Studies about students’ learning with dynamic geometry tools usually focus on the lon...

  13. First principles molecular dynamics simulation of a task-specific ionic liquid based on silver-olefin complex: atomistic insight into separation process

    CERN Document Server

    Jiang, De-en

    2008-01-01

    First principles molecular dynamics based on density functional theory is applied to a hypothetical ionic liquid whose cations and anions are silver-ethylene complex [Ag(C2H4)2+] and tetrafluoroborate [BF4-], respectively. This ionic liquid represents a group of task-specific silver complex-based ionic liquids synthesized recently. Molecular dynamics simulations at two temperatures are performed for five picoseconds. Events of association, dissociation, exchange, and recombination of ethylene with silver cation are observed. A mechanism of ethylene transfer similar to the Grotthus type of proton transfer in water is identified, where a silver cation accepts one ethylene molecule and donates another to a neighboring silver cation. This mechanism may contribute to fast transport of olefins through ionic liquid membranes based on silver complexes for olefin/paraffin separation.

  14. First principles molecular dynamics simulation of a task-specific ionic liquid based on silver-olefin complex: atomistic insights into a separation process.

    Science.gov (United States)

    Jiang, De-en; Dai, Sheng

    2008-08-21

    First principles molecular dynamics based on density functional theory is applied to a hypothetical ionic liquid whose cations and anions are silver-ethylene complex [Ag(C2H4)2+] and tetrafluoroborate [BF4-], respectively. This ionic liquid represents a group of task-specific silver complex-based ionic liquids synthesized recently. Molecular dynamics simulations at two temperatures are performed for five picoseconds. Events of association, dissociation, exchange, and recombination of ethylene with silver cation are found. A mechanism of ethylene transfer similar to the Grotthus type of proton transfer in water is identified, where a silver cation accepts one ethylene molecule and donates another to a neighboring silver cation. This mechanism may contribute to fast transport of olefins through ionic liquid membranes based on silver complexes for olefin/paraffin separation.

  15. A Heuristic and Dynamic Method for Task Scheduling and Path Planning%启发式动态任务调度与航路规划方法

    Institute of Scientific and Technical Information of China (English)

    沈淑梅; 姚臣

    2012-01-01

    A hierarchical structure of mission planning system was proposed for task scheduling and path planning. The multi-task priority and conflict resolution were implemented in the upper layer of the mission planning system, and path planning and real-time re-planning were implemented in the lower layer. The algorithms of heuristic and dynamic task scheduling and path planning were proposed, which can improve the situation adaptability and conflict resolution ability to various emergencies, and the capability to attack time-critical target, and thus can increase the autonomy level of UAV under dynamic and uncertain environment.%针对任务、资源、航路的调度与规划需要,建立了一种分层递阶的任务规划系统结构,上层主要解决任务优先级和冲突消解问题;下层主要解决满足各种要求的航路规划与实时重规划问题.提出了启发式动态任务调度与航路实时规划算法,可以有效提高对各种突发事件的态势自适应和冲突消解能力以及对时敏目标的打击能力,进而提高无人机在动态不确定环境下的自主性.

  16. Subject-specific tendon-aponeurosis definition in Hill-type model predicts higher muscle forces in dynamic tasks.

    Directory of Open Access Journals (Sweden)

    Pauline Gerus

    Full Text Available Neuromusculoskeletal models are a common method to estimate muscle forces. Developing accurate neuromusculoskeletal models is a challenging task due to the complexity of the system and large inter-subject variability. The estimation of muscles force is based on the mechanical properties of tendon-aponeurosis complex. Most neuromusculoskeletal models use a generic definition of the tendon-aponeurosis complex based on in vitro test, perhaps limiting their validity. Ultrasonography allows subject-specific estimates of the tendon-aponeurosis complex's mechanical properties. The aim of this study was to investigate the influence of subject-specific mechanical properties of the tendon-aponeurosis complex on a neuromusculoskeletal model of the ankle joint. Seven subjects performed isometric contractions from which the tendon-aponeurosis force-strain relationship was estimated. Hopping and running tasks were performed and muscle forces were estimated using subject-specific tendon-aponeurosis and generic tendon properties. Two ultrasound probes positioned over the muscle-tendon junction and the mid-belly were combined with motion capture to estimate the in vivo tendon and aponeurosis strain of the medial head of gastrocnemius muscle. The tendon-aponeurosis force-strain relationship was scaled for the other ankle muscles based on tendon and aponeurosis length of each muscle measured by ultrasonography. The EMG-driven model was calibrated twice - using the generic tendon definition and a subject-specific tendon-aponeurosis force-strain definition. The use of subject-specific tendon-aponeurosis definition leads to a higher muscle force estimate for the soleus muscle and the plantar-flexor group, and to a better model prediction of the ankle joint moment compared to the model estimate which used a generic definition. Furthermore, the subject-specific tendon-aponeurosis definition leads to a decoupling behaviour between the muscle fibre and muscle-tendon unit

  17. Variability in spatio-temporal pattern of trapezius activity and coordination of hand-arm muscles during a sustained repetitive dynamic task

    DEFF Research Database (Denmark)

    Samani, Afshin; Srinivasan, Divya; Mathiassen, Svend Erik;

    2016-01-01

    The spatio-temporal distribution of muscle activity has been suggested to be a determinant of fatigue development. Pursuing this hypothesis, we investigated the pattern of muscular activity in the shoulder and arm during a repetitive dynamic task performed until participants' rating of perceived...... power frequency (MNF) were calculated for all EMG signals. The barycenter of RMS values over the HD-EMG grid was also determined, as well as normalized mutual information (NMI) for each pair of muscles. Cycle-to-cycle variability of these metrics was also assessed. With time, EMG RMS increased for most...... of the muscles, and MNF decreased. Trapezius activity became higher on the lateral side than on the medial side of the HD-EMG grid and the barycenter moved in a lateral direction. NMI between muscle pairs increased with time while its variability decreased. The variability of the metrics during the initial 10...

  18. Comparison of proximally versus distally placed spatially distributed sequential stimulation electrodes in a dynamic knee extension task

    Directory of Open Access Journals (Sweden)

    Marco Laubacher

    2016-06-01

    Full Text Available Spatially distributed sequential stimulation (SDSS has demonstrated substantial power output and fatigue benefits compared to single electrode stimulation (SES in the application of functional electrical stimulation (FES. This asymmetric electrode setup brings new possibilities but also new questions since precise placement of the electrodes is one critical factor for good muscle activation. The aim of this study was to compare the power output, fatigue and activation properties of proximally versus distally placed SDSS electrodes in an isokinetic knee extension task simulating knee movement during recumbent cycling. M. vastus lateralis and medialis of seven able-bodied subjects were stimulated with rectangular bi-phasic pulses of constant amplitude of 40 mA and at an SDSS frequency of 35 Hz for 6 min on both legs with both setups (i.e. n=14. Torque was measured during knee-extension movement by a dynamometer at an angular velocity of 110 deg/s. Mean power, peak power and activation time were calculated and compared for the initial and final stimulation phases, together with an overall fatigue index. Power output values (Pmean, Ppeak were scaled to a standardised reference input pulse width of 100 μs (Pmean,s, Ppeak,s. The initial evaluation phase showed no significant differences between the two setups for all outcome measures. Ppeak and Ppeak,s were both significantly higher in the final phase for the distal setup (25.4 ± 8.1 W vs. 28.2 ± 6.2 W, p=0.0062 and 34.8 ± 9.5 W vs. 38.9 ± 6.7 W, p=0.021, respectively. With distal SDSS, there was modest evidence of higher Pmean and Pmean,s (p=0.071, p=0.14, respectively but of longer activation time (p=0.096. The rate of fatigue was similar for both setups. For practical FES applications, distal placement of the SDSS electrodes is preferable.

  19. Frontal plane multi-segment foot kinematics in high- and low-arched females during dynamic loading tasks.

    Science.gov (United States)

    Powell, Douglas W; Long, Benjamin; Milner, Clare E; Zhang, Songning

    2011-02-01

    The functions of the medial longitudinal arch have been the focus of much research in recent years. Several studies have shown kinematic differences between high- and low-arched runners. No literature currently compares the inter-segmental foot motion of high- and low-arched recreational athletes. The purpose of this study was to examine inter-segmental foot motion in the frontal plane during dynamic loading activities in high- and low-arched female athletes. Inter-segmental foot motions were examined in 10 high- and 10 low-arched female recreational athletes. Subjects performed five barefooted trials in each of the following randomized movements: walking, running, downward stepping and landing. Three-dimensional kinematic data were recorded. High-arched athletes had smaller peak ankle eversion angles in walking, running and downward stepping than low-arched athletes. At the rear-midfoot joint high-arched athletes reached peak eversion later in walking and downward stepping than the low-arched athletes. The high-arched athletes had smaller peak mid-forefoot eversion angles in walking, running and downward stepping than the low-arched athletes. The current findings show that differences in foot kinematics between the high- and low-arched athletes were in position and not range of motion within the foot.

  20. CEINMS: A toolbox to investigate the influence of different neural control solutions on the prediction of muscle excitation and joint moments during dynamic motor tasks.

    Science.gov (United States)

    Pizzolato, Claudio; Lloyd, David G; Sartori, Massimo; Ceseracciu, Elena; Besier, Thor F; Fregly, Benjamin J; Reggiani, Monica

    2015-11-01

    Personalized neuromusculoskeletal (NMS) models can represent the neurological, physiological, and anatomical characteristics of an individual and can be used to estimate the forces generated inside the human body. Currently, publicly available software to calculate muscle forces are restricted to static and dynamic optimisation methods, or limited to isometric tasks only. We have created and made freely available for the research community the Calibrated EMG-Informed NMS Modelling Toolbox (CEINMS), an OpenSim plug-in that enables investigators to predict different neural control solutions for the same musculoskeletal geometry and measured movements. CEINMS comprises EMG-driven and EMG-informed algorithms that have been previously published and tested. It operates on dynamic skeletal models possessing any number of degrees of freedom and musculotendon units and can be calibrated to the individual to predict measured joint moments and EMG patterns. In this paper we describe the components of CEINMS and its integration with OpenSim. We then analyse how EMG-driven, EMG-assisted, and static optimisation neural control solutions affect the estimated joint moments, muscle forces, and muscle excitations, including muscle co-contraction. PMID:26522621

  1. The Impact of Task Demands on Fixation-Related Brain Potentials during Guided Search

    Science.gov (United States)

    Ahrens, Barry; Connolly, Patrick

    2016-01-01

    Recording synchronous data from EEG and eye-tracking provides a unique methodological approach for measuring the sensory and cognitive processes of overt visual search. Using this approach we obtained fixation related potentials (FRPs) during a guided visual search task specifically focusing on the lambda and P3 components. An outstanding question is whether the lambda and P3 FRP components are influenced by concurrent task demands. We addressed this question by obtaining simultaneous eye-movement and electroencephalographic (EEG) measures during a guided visual search task while parametrically modulating working memory load using an auditory N-back task. Participants performed the guided search task alone, while ignoring binaurally presented digits, or while using the auditory information in a 0, 1, or 2-back task. The results showed increased reaction time and decreased accuracy in both the visual search and N-back tasks as a function of auditory load. Moreover, high auditory task demands increased the P3 but not the lambda latency while the amplitude of both lambda and P3 was reduced during high auditory task demands. The results show that both early and late stages of visual processing indexed by FRPs are significantly affected by concurrent task demands imposed by auditory working memory. PMID:27286248

  2. The binaural free field hearing threshold for pure tones from 125 Hz to 16 kHz

    DEFF Research Database (Denmark)

    Poulsen, Torben; Han, Loc A

    2000-01-01

    The binaural free field hearing threshold for pure tones has been measured for thirty-one otologically normal test subjects in the age range 18 to 25 years. The frequencies were 0.125, 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 8, 9, 10, 11.2, 12.5, 14 and 16 kHz. The signal duration was 1 s measured...... between the half amplitude points of the rise and fall course. The pure tone signals were generated from disk files. The thresholds were determined with the Bracketing Method (ISO 8253-1) using a step size of 5 dB. The results are in good agreement with ISO 389-7 and with other recent determinations...... of the free field hearing threshold. At 1500 Hz a small local peak in the threshold is seen which is not reflected in the present standards.PACS 43.66 Cb; 43.66 Pn...

  3. The observation of theta wave modulation on brain training by 5 Hz-binaural beat stimulation in seven days.

    Science.gov (United States)

    Yamsa-Ard, Traisak; Wongsawat, Yodchanan

    2015-08-01

    Traditional buddhist meditation method maybe easy for someone with high experience. However, for the beginner, it is very difficult to keep mental concentration with the tradition way for more than 5 minutes. This research aims to observe effect of the new method for meditation in various analysis methods. A piano music mixed with a 5 Hz (theta band enhancement) binaural beat frequency was used to modulate the brain signals continuously for 7 days. Male of the average age of 33.5±3.84 and female of the average age of 28.6±2.49 were participated. All participants were acquired EEGs twice, before the experiment and seven days after the experiment. We also proposed the observations on the changes of absolute powers, relative powers and brain connectivity (coherence) of the participants. After seven days of training, the absolute power, relative power, and coherence were clearly closer to the normative database. We can initially say that the recommended meditation method can efficiently mimic the effect of having the traditional buddhist meditation on enhancing the delta and theta powers in the brain. PMID:26737822

  4. Dynamic alliance collaborative tasks of WSNs based on swarm intelligence algorithm%基于群智能算法的WSNs动态联盟任务协同

    Institute of Scientific and Technical Information of China (English)

    陈莹; 李影洁; 朱思峰

    2014-01-01

    In response to the limited computing power and difficulties in completing data transmission of a single node in wireless sensor networks ( WSNs ) , this paper proposes a co-processing data-transmitting method that can divide the cooperative task into perception and computation. By introducing the particle swarm optimization ant colony algorithm ( PSO-ACO ) into the dynamic alliance of task collaboration of sensing nodes,the data collection routing tree of the sensor network is built. Based on the correlation of data collection in the sensor network, the swarm intelligence algorithm is used to optimize the transmission path of the data sent by the nodes to ensure the continuity of the dynamic alliance in executing the tasks. In this way,the performance of the sensor network is ensured to some extent and the communication energy consumption is reduced accordingly. Simulation experiments indicate that,the sensor network achieves optimal monitoring performance when the percentage of sensing nodes in the total number of nodes in the network is less than 28%. The scheme proposed here can eliminate the sensor node redundancy detected in the same task and reduce energy consumption of the system.%针对无线传感器网络( Wireless sensor networks,WSNs)中单个节点的计算能力有限、完成数据发送任务比较困难的问题,提出一种协同处理的方式传送数据,可以将协同任务分为感知子任务和计算子任务。在传感节点任务协同的动态联盟中,引入基于粒子群算法优化蚁群算法(Particle swarm optimization ant colony algorithm,PSO-ACO)构建传感网的数据汇集路由树。利用传感器网络在采集数据之间的相关性,运用群智能算法来优化节点发送数据的传输路径,以保证动态联盟执行任务时的连续性,在一定程度上保证传感网的性能,从而降低了通信能耗。仿真实验表明:当传感器网络的感知节点与网络节点总数的比值小于28%时,网络

  5. Spatial and temporal dynamics of visual search tasks distinguish subtypes of unilateral spatial neglect: Comparison of two cases with viewer-centered and stimulus-centered neglect.

    Science.gov (United States)

    Mizuno, Katsuhiro; Kato, Kenji; Tsuji, Tetsuya; Shindo, Keiichiro; Kobayashi, Yukiko; Liu, Meigen

    2016-08-01

    We developed a computerised test to evaluate unilateral spatial neglect (USN) using a touchscreen display, and estimated the spatial and temporal patterns of visual search in USN patients. The results between a viewer-centered USN patient and a stimulus-centered USN patient were compared. Two right-brain-damaged patients with USN, a patient without USN, and 16 healthy subjects performed a simple cancellation test, the circle test, a visuomotor search test, and a visual search test. According to the results of the circle test, one USN patient had stimulus-centered neglect and a one had viewer-centered neglect. The spatial and temporal patterns of these two USN patients were compared. The spatial and temporal patterns of cancellation were different in the stimulus-centered USN patient and the viewer-centered USN patient. The viewer-centered USN patient completed the simple cancellation task, but paused when transferring from the right side to the left side of the display. Unexpectedly, this patient did not exhibit rightward attention bias on the visuomotor and visual search tests, but the stimulus-centered USN patient did. The computer-based assessment system provided information on the dynamic visual search strategy of patients with USN. The spatial and temporal pattern of cancellation and visual search were different across the two patients with different subtypes of neglect.

  6. Relating hearing loss and executive functions to hearing aid users’ preference for, and speech recognition with, different combinations of binaural noise reduction and microphone directionality

    Directory of Open Access Journals (Sweden)

    Tobias eNeher

    2014-12-01

    Full Text Available Knowledge of how executive functions relate to preferred hearing aid (HA processing is sparse and seemingly inconsistent with related knowledge for speech recognition outcomes. This study thus aimed to find out if (1 performance on a measure of reading span (RS is related to preferred binaural noise reduction (NR strength, (2 similar relations exist for two different, nonverbal measures of executive function, (3 pure-tone average hearing loss (PTA, signal-to-noise ratio (SNR, and microphone directionality (DIR also influence preferred NR strength, and (4 preference and speech recognition outcomes are similar. Sixty elderly HA users took part. Six HA conditions consisting of omnidirectional or cardioid microphones followed by inactive, moderate, or strong binaural NR as well as linear amplification were tested. Outcome was assessed at fixed SNRs using headphone simulations of a frontal target talker in a busy cafeteria. Analyses showed positive effects of active NR and DIR on preference, and negative and positive effects of, respectively, strong NR and DIR on speech recognition. Also, while moderate NR was the most preferred NR setting overall, preference for strong NR increased with SNR. No relation between RS and preference was found. However, larger PTA was related to weaker preference for inactive NR and stronger preference for strong NR for both microphone modes. Equivalent (but weaker relations between worse performance on one nonverbal measure of executive function and the HA conditions without DIR were found. For speech recognition, there were relations between HA condition, PTA, and RS, but their pattern differed from that for preference. Altogether, these results indicate that, while moderate NR works well in general, a notable proportion of HA users prefer stronger NR. Furthermore, PTA and executive functions can account for some of the variability in preference for, and speech recognition with, different binaural NR and DIR settings.

  7. 基于MAS的动态协作任务求解模型与算法%Dynamic collaboration tasks based on MAS model and algorithm for solving

    Institute of Scientific and Technical Information of China (English)

    蒋伟进; 蒋星军; 姚丽娜

    2013-01-01

    Dynamic grid resources scheduling which aims at improving resource utilization and grid application performance is a key concern in grid. Currently, much research can be found about grid scheduling and some algorithms on it were proposed. However, since grid resources are autonomic, distributed and their status change over time, those scheduling algorithms did not fit for the cases well. With MAS(Multi Agent System) coordinated technology and market bidding game rules, a grid resource allocation model based on market economy was introduced, which could show the relation between supply and demand. The model could make full use of the computing and negotiating power of the consumer and could fully consider the consumer behavior. It made the resource application and assignment of the consumer reach the higher rationality and effectiveness. In the meantime the utility function of the consumer was given; the entity and the uniqueness of Nash equilibrium in the resource allocation game and the Nash equilibrium solution were discussed. A grid resource allocation algorithm was designed based on the distilled resource allocation model. Experimental results demonstrate that this approach diminishes latency, contributes to the overall grid load balancing, and significantly improves resource utilization and the response time of tasks, which enables the allocation of the whole grid resource to be more reasonable.%为提高动态网格资源的利用率,提出了基于多智能体系统博弈协作的任务动态分配和协作求解模型,建立了网格资源调度模型和任务求解算法,证明了资源分配博弈中Nash均衡点的存在性、唯一性和Nash均衡解.该方法能够利用用户智能体的学习和行为能力,使得用户的资源申请和任务调度具有较高的合理性和有效性.进行了供求关系中竞价博弈的模型试验.实验结果表明,资源调度算法不但可以有效减少延迟,而且在响应时间的平滑性、吞吐率

  8. Short-term learning of a visually guided power-grip task is associated with dynamic changes in EEG oscillatory activity

    OpenAIRE

    Kranczioch, C.; Athanassiou, S.; Shen, S; G. Gao; A. Sterr

    2008-01-01

    Objective: Performing a motor task after a period of training has been associated with reduced cortical activity and changes in oscillatory brain activity. Little is known about whether learning also affects the neural network associated with motor preparation and post movement processes. Here we investigate how short-term motor learning affects oscillatory brain activity during the preparation, execution, and post-movement stage of a force-feedback task. Methods: Participants performed a vis...

  9. Dynamic Spatial Hearing by Human and Robot Listeners

    Science.gov (United States)

    Zhong, Xuan

    This study consisted of several related projects on dynamic spatial hearing by both human and robot listeners. The first experiment investigated the maximum number of sound sources that human listeners could localize at the same time. Speech stimuli were presented simultaneously from different loudspeakers at multiple time intervals. The maximum of perceived sound sources was close to four. The second experiment asked whether the amplitude modulation of multiple static sound sources could lead to the perception of auditory motion. On the horizontal and vertical planes, four independent noise sound sources with 60° spacing were amplitude modulated with consecutively larger phase delay. At lower modulation rates, motion could be perceived by human listeners in both cases. The third experiment asked whether several sources at static positions could serve as "acoustic landmarks" to improve the localization of other sources. Four continuous speech sound sources were placed on the horizontal plane with 90° spacing and served as the landmarks. The task was to localize a noise that was played for only three seconds when the listener was passively rotated in a chair in the middle of the loudspeaker array. The human listeners were better able to localize the sound sources with landmarks than without. The other experiments were with the aid of an acoustic manikin in an attempt to fuse binaural recording and motion data to localize sounds sources. A dummy head with recording devices was mounted on top of a rotating chair and motion data was collected. The fourth experiment showed that an Extended Kalman Filter could be used to localize sound sources in a recursive manner. The fifth experiment demonstrated the use of a fitting method for separating multiple sounds sources.

  10. Dimensions of Organizational Task Environments.

    Science.gov (United States)

    Dess, Gregory G.; Beard, Donald W.

    1984-01-01

    Reducing Aldrich's codification of organizational task environments from six to three dimensions--munificence (capacity), complexity (homogeneity-heterogeneity, concentration-dispersion), and dynamism (stability-instability, turbulence), the authors use interim and factor analytical techniques to explore each dimension's viability and draw…

  11. A Task Duplication Algorithm Based on Dynamic Critical Path and Edge-Zeroing%基于动态关键路径与边消除的任务复制分配算法

    Institute of Scientific and Technical Information of China (English)

    尤涛; 杨凯; 杜承烈; 钟冬; 朱怡安

    2013-01-01

    当前的分布式任务调度算法中,都存在无法得到调度最优解、无法最小化处理器资源的问题。针对并行与分布式系统中相关任务的静态调度问题,以最小化调度长度为主要目标,以减少资源数为次要目标,提出了一种基于动态关键路径与边消除的任务复制算法。该算法依据调度长度不增加原则,发展了子节点无约束复制的调度长度不增加定理、子结点带约束复制的调度长度不增加原则、动态关键路径聚簇的调度长度不增加原则,从而缩短了任务的执行时间和占用资源的个数。整个算法流程对任务计算时间与任务间通信时间未做任何限制。通过与相关工作的比较可以看出:DDE算法在调度长度与处理器使用数目上优于其他同类算法。%Task scheduling is critical for a parallel and distributed system .The task duplication and scheduling al-gorithm and other typical algorithms cannot obtain the optimal solutions for scheduling length even under optimal conditions.Moreover, they are constrained by the node selection scope and node execution time scope when alloca-ting nodes, being unable to minimize the number of processors required by the algorithms .To carry out the static scheduling of the related tasks in the parallel and distributed system , this paper proposes the task in the parallel and distributed system , this paper proposes the task duplication algorithm based on dynamic critical path and edge -zeroing , whose main objective is to reduce the number of resources .The algorithm develops the principles that the scheduling length of sub-nodes that are duplicated with no constraints should not increase , that the scheduling length of sub-nodes that are duplicated with constraints should not increase and the scheduling length of dynamic critical path clustering should not increase , thus reducing the task execution time and the number of resources used . The algorithm

  12. Dynamics sequential logic model and mechanism for cooperation to solve task of complex self-adaptive multi-agent systems%复杂系统的MAS动态协作求解时序逻辑模型

    Institute of Scientific and Technical Information of China (English)

    蒋伟进; 蒋星军; 姚丽娜

    2012-01-01

    借助于组织学思想,将自适应系统中的自主运行单元抽象为Agent,把复杂自适应系统视为多Agent组织,从时间和状态角度,对复杂动态系统的行为进行描述.提出了基于时序活动逻辑的多Agent动态协作任务求解自适应机制和构造模型;详细分析了任务求解BDIAgent的信念、愿望、意图的产生过程和实现方法;深入讨论了协商推理的语义规则和行为规则;给出了协作群组的选择算法,包括从群组的建立、选择任务Agent、分解和分配子任务;从任务求解Agent的心智变化角度,详细描述了动态协作任务求解模型实现的6个阶段:任务动态分配、协作意愿产生、协作群体生成、共同计划制定、协作群体行动和结果评估.通过在MAGE等平台上的实验和仿真测试,验证了方法的可行性和有效性.%From the ideas of tissue,the running unit of the self-adaptive system was abstracted as Agent.The complex adaptive system was regarded as a multi-Agent organization. From the perspective of time and status the behavior of the complex dynamic systems was described. Temporal logic multi-Agent based dynamic adaptive mechanisms and the task solving cooperation structure model were proposed. Detailed a-nalysis was made of the task to solve BDI Agenfs belief, desire, intention and realization of the production process. The negotiation of rules and semantic inference rules of conduct was fully discussed. The collaborative group selection algorithm was presented, including the establishment from the group. Selection of the Task Agent, decomposition and allocation of subtasks. From the changing angle of the Agenfs mind to solve the task, a detailed description was given of the task to solve the model to achieve dynamic collaboration of six stages: dynamic allocation of tasks, collaboration production, collaborative groups generation, common planning, collaborative groups, action and evaluation of results

  13. INCIDENCIA DE TAREAS DE APRENDIZAJE EN LA DINÁMICA DEL INTERÉS. UN ESTUDIO EN EDUCACIÓN TECNOLÓGICA (INCIDENCE OF LEARNING TASKS IN THE DYNAMICS OF INTEREST. A STUDY IN TECHNOLOGICAL EDUCATION

    Directory of Open Access Journals (Sweden)

    Hirigoyen María Amelia

    2011-04-01

    findings from a descriptive, instructional designs based on the impact of tasks considered the Science-Technology-Society-Environment (contextualized tasks and those who did not (not contextualized tasks, the dynamics of students' interest in the subject Technology Education. That is to say, we aimed to analyze and discuss whether the proposed tasks produced a greater or lesser interest in the students for their achievement. Data were collected through classroom observations, which responded to the qualitative paradigm of research, conducted in 2009. We worked with students in sixth grade, freshman and junior year and with their teachers in the city of Rio Cuarto (Cordoba, Argentina and in a nearby locality. The results confirmed that the contextualized tasks that were included in the content of technology (biotechnology, greenhouse, etc. To pose problems related to scientific, social and environmental generated interest among students. However, the study showed that contextualize the work was not always sufficient and necessary factors were linked to the promotion of interest-called situational interest factors, such as mode of presentation of tasks, explanations of the goals of the tasks and feedback on its realization, etc. Thus, we identified indicators of student interest (request for assistance, consultation questions, showing progress, permanence tasks, etc. and situational interest factors already mentioned. Consideration of situational interest and the contextualization of the tasks in the teaching of technology becomes important to promote the interests of individual students.

  14. Multi-agent tasks scheduling system in software defined networks

    International Nuclear Information System (INIS)

    In this paper a multi-agent tasks scheduling system in software defined networks is considered. This system is designed for distribution simulation and tasks implementation on computational resources including network dynamic characteristics and topology.

  15. Brainwave Acousto-Optic Adjuster Based on Binaural Auditory Beat%基于双声拍的脑电波声光调节装置

    Institute of Scientific and Technical Information of China (English)

    张晓磊; 姚俊强; 沈斌; 应家顺; 彭雪峰

    2013-01-01

    A brainwave acousto-optic adjuster based on binaural auditory beat was designed by the use of the ATmega8.When two tones of slightly different frequency are presented separately to the left and right ears,the listener perceives a single tone that varies in amplitude at a frequency equal to the frequency difference between the two tones,which was known as "Binaural Auditory Beats (BAT)".The BAT within the brainwave frequency range can affect brain activity and states of consciousness,so we can adjust the brainwave by the BAT.Make use of this law,we product two auditory signals with different frequency by ATmega8,after low pass filter,presented separately to the left and right ear,formed BAT,then set two LEDs flash with the same frequency as the BAT before the left and right eyes.The combined action of light and BAT with the same frequency could adjust the brainwave arbitrarily.%利用ATmega8单片机制作了一种基于双声拍的脑电波光电调节装置.两列频率差别较小的声波分别输入人的左右耳中,会产生一种振幅周期性变化的新的声波,新声波的频率为原来两列声波的频率差,这种现象称为“双声拍”.双声拍的频率位于人脑电波范围时会影响大脑的活跃程度和意识状态,通过调节双声拍的频率即可调节脑电波.基于这一原理,本文利用ATmega8单片机产生两列声波,低通滤波后将不同频率的声波通过左右耳输入大脑,形成“双声拍”;再将双眼前放置两个闪烁频率与双声拍频相同的LED,在声光的共同作用下,可以达到任意调节脑电波频率的目的.

  16. Sound source localization based on binaural cross-correlation functions%基于双耳互相关函数的声源定位算法

    Institute of Scientific and Technical Information of China (English)

    万新旺; 吴镇扬

    2011-01-01

    为了提高受生物启发的定位算法的定位成功率,提出了一种基于双耳互相关函数的声源定位算法.该算法包括2个阶段:离线阶段和在线阶段.在离线阶段,测量与头相关脉冲响应(HRIR),并计算所有HRIR的双耳互相关函数(BCCF).当处于在线阶段时,首先,计算接收信号的BCCF;然后,计算接收信号的BCCF与所有HRIR的BCCF之间的Pearson相关系数;最后,将最大的Pearson相关系数对应的方位作为估计的声源方位.实验结果表明,在有2个声源同时存在的情况下,相对于互通道(cross-channel)定位算法,该算法把主峰定位成功率和次峰定位成功率分别提高了约1.64%和26.48%.%To improve the successful localization rate of the biologically inspired sound source localization method, a sound source localization algorithm based on binaural cross-correlation functions is proposed. The proposed method contains two phases: offline phase and online phase. During the offline phase, the head-related impulse responses (HRIR) are measured, and the binaural cross-correlation functions (BCCF) of the HRIRs are calculated. During the online phase, first, the BCCF of the received signals is computed; then Pearson correlation coefficient between the BCCF of the received signals and that of the HRIRs are calculated; finally, the azimuth corresponding to the largest Pearson correlation coefficient is regarded as the azimuth of the sound source. The experimental results show that when two sound sources are simultaneously present, compared with the cross-channel sound source localization method, the proposed algorithm increases the successful localization rate of the main peak and that of the second peak by about 1.64% and 26.48% , respectively.

  17. Heuristic Based Task Scheduling In Grid

    Directory of Open Access Journals (Sweden)

    Manpreet Singh

    2012-09-01

    Full Text Available Grid computing is concerned with coordinated resource sharing and problem solving in dynamic, multi-institutional virtual organizations. Efficient scheduling of complex applications in a grid environment reveals several challenges due to its high heterogeneity, dynamic behavior and space shared utilization. Objectives of scheduling algorithms are increase in system throughput, efficiency and reduction in task completion time. The main focus of this paper is to highlight the merits of resource and task selection technique based on certain heuristics.

  18. 基于内分泌调节原理的制造任务与资源动态协调机制研究%Dynamic Coordination among Manufacturing Resources and Tasks Based on Endocrine Regulation Principle

    Institute of Scientific and Technical Information of China (English)

    顾文斌; 唐敦兵; 郑堃

    2015-01-01

    For solving the coordination problems of tasks and resources in dynamic manufacturing environments,the optimization process of the coordination problems among tasks and resources was analyzed,and a mathematical model was established.Inspired by the endocrine regulation principle, two kinds of hormone(task hormone and resource hormone)were designed.Considering the influences of the emergency in manufacturing system,a novel dynamic coordination approach was proposed based on the hormone regulation principle.This proposed approach was characterized by higher effi-ciency,lower communication,and better robustness.A prototype system was developed,and experi-mental results confirm that the approach has excellent stability and optimization ability for task alloca-tion problems in a static environment,and it also has excellent control performance and adaptability to disturbances in shop floor.%针对制造系统在动态环境下的任务与资源协调优化问题,在保证按时完工的前提下,分析了制造任务与资源协调优化过程,建立了数学模型。受人体内分泌调节机制的启发,设计了两种可以相互影响的激素(任务相关激素和资源相关激素),同时,考虑到突发事件对制造系统工作性能的影响,提出了基于激素的资源与任务的动态协调算法。实例验证表明,该算法切实可行,具有任务分配质量高、动态协调性能好、协调过程通信量小、控制系统鲁棒性较好等优点。

  19. Recalling academic tasks

    Science.gov (United States)

    Draper, Franklin Gno

    This study was focused on what students remembered about five middle school science tasks when they were juniors and seniors in high school. Descriptions of the five tasks were reconstructed from available artifacts and teachers' records, notes and recollections. Three of the five tasks were "authentic" in the sense that students were asked to duplicate the decisions practitioners make in the adult world. The other two tasks were more typical school tasks involving note taking and preparation for a quiz. All five tasks, however, involved use of computers. Students were interviewed to examine what and how well they recalled the tasks and what forms or patterns of recall existed. Analysis of their responses indicated that different kinds of tasks produced different levels of recall. Authentically situated tasks were remembered much better than routine school tasks. Further, authentic tasks centered on design elements were recalled better than those for which design was not as pivotal. Patterns of recall indicated that participants most often recalled the decisions they made, the scenarios of the authentically situated tasks, the consequences of their tasks and the social contexts of the classroom. Task events, in other words, appeared to form a framework upon which students constructed stories of the tasks. The more salient the events, the richer the story, the deeper and more detailed the recall of the task. Thus, authentic tasks appeared to lend themselves to creating stories better than regular school tasks and therefore such tasks were recalled better. Implications of these patterns of recall are discussed with respect to issues of school learning and assessment.

  20. Multi-granularity dynamic access control model based on tasks and roles%基于任务和角色的多粒度动态访问控制模型

    Institute of Scientific and Technical Information of China (English)

    彭佳玮; 孙国强; 杨少友

    2016-01-01

    To resolve the problems existing in the traditional access control model,an improved model called multi-granularity dynamic access control model based on tasks and roles (MG-TRBAC)was present.A supervision mechanism concept was added based on the TRBAC model,roles and tasks were dynamically managed and associated to improve the rigor,security,and initia-tive of access control.To make the multi-granularity access authorization more flexible,the authorization process was decom-posed into page level,function level and data level,and a new strategy module associating with the authorization of data layer for data accessing was added.The implementation of the model in a proj ect shows that the model can effectively meet the needs of the project for access control,verifying the feasibility of the model.%对传统的访问控制模型存在的问题进行分析,提出一种基于任务和角色的多粒度动态访问控制模型 (MG-TR-BAC).在TRBAC模型基础上新增监管机制概念,通过对角色和任务进行约束管理和动态关联,提升访问控制的严密性、安全性和主动性;将授权过程分解为页面、功能、数据3个层次,新增数据访问策略模块与数据层授权关联,实现更加灵活的多粒度访问授权.项目实现结果表明,该模型能够有效满足项目对访问控制的需求,体现了模型的可行性.

  1. Project Tasks in Robotics

    DEFF Research Database (Denmark)

    Sørensen, Torben; Hansen, Poul Erik

    1998-01-01

    Description of the compulsary project tasks to be carried out as a part of DTU course 72238 Robotics......Description of the compulsary project tasks to be carried out as a part of DTU course 72238 Robotics...

  2. Dynamic Task Assignment and Path Planning of Multi-AUV System Based on an Improved Self-Organizing Map and Velocity Synthesis Method in Three-Dimensional Underwater Workspace.

    Science.gov (United States)

    Zhu, Daqi; Huang, Huan; Yang, S X

    2013-04-01

    For a 3-D underwater workspace with a variable ocean current, an integrated multiple autonomous underwater vehicle (AUV) dynamic task assignment and path planning algorithm is proposed by combing the improved self-organizing map (SOM) neural network and a novel velocity synthesis approach. The goal is to control a team of AUVs to reach all appointed target locations for only one time on the premise of workload balance and energy sufficiency while guaranteeing the least total and individual consumption in the presence of the variable ocean current. First, the SOM neuron network is developed to assign a team of AUVs to achieve multiple target locations in 3-D ocean environment. The working process involves special definition of the initial neural weights of the SOM network, the rule to select the winner, the computation of the neighborhood function, and the method to update weights. Then, the velocity synthesis approach is applied to plan the shortest path for each AUV to visit the corresponding target in a dynamic environment subject to the ocean current being variable and targets being movable. Lastly, to demonstrate the effectiveness of the proposed approach, simulation results are given in this paper.

  3. Dynamic Task Assignment and Path Planning of Multi-AUV System Based on an Improved Self-Organizing Map and Velocity Synthesis Method in Three-Dimensional Underwater Workspace.

    Science.gov (United States)

    Zhu, Daqi; Huang, Huan; Yang, S X

    2013-04-01

    For a 3-D underwater workspace with a variable ocean current, an integrated multiple autonomous underwater vehicle (AUV) dynamic task assignment and path planning algorithm is proposed by combing the improved self-organizing map (SOM) neural network and a novel velocity synthesis approach. The goal is to control a team of AUVs to reach all appointed target locations for only one time on the premise of workload balance and energy sufficiency while guaranteeing the least total and individual consumption in the presence of the variable ocean current. First, the SOM neuron network is developed to assign a team of AUVs to achieve multiple target locations in 3-D ocean environment. The working process involves special definition of the initial neural weights of the SOM network, the rule to select the winner, the computation of the neighborhood function, and the method to update weights. Then, the velocity synthesis approach is applied to plan the shortest path for each AUV to visit the corresponding target in a dynamic environment subject to the ocean current being variable and targets being movable. Lastly, to demonstrate the effectiveness of the proposed approach, simulation results are given in this paper. PMID:22949070

  4. Launching Complex Tasks

    Science.gov (United States)

    Jackson, Kara J.; Shahan, Emily C.; Gibbons, Lynsey K.; Cobb, Paul A.

    2012-01-01

    Mathematics lessons can take a variety of formats. In this article, the authors discuss lessons organized around complex mathematical tasks. These lessons usually unfold in three phases. First, the task is introduced to students. Second, students work on solving the task. Third, the teacher "orchestrates" a concluding whole-class discussion in…

  5. Dynamics

    CERN Document Server

    Goodman, Lawrence E

    2001-01-01

    Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

  6. Psychophysiological reactivity to auditory Binaural Beats stimulation in the alpha and theta EEG brain-wave frequency bands: A randomized, double–blind and placebo–controlled study in human healthy young adult subjects

    OpenAIRE

    Pfaff, Hans Uwe

    2014-01-01

    Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Psicología, Departamento de Psicología Biológica y de la Salud. Fecha de lectura: 25-06-2014 Binaural beats are an acoustical illusion of the perception of a “virtual” third tone, fluctuating (i.e. beating) in its volume evoked by two carrier–sinusoids of same amplitudes, but slightly different frequencies f1 and f2, presented by stereo-headphones. Although this illusion was discovered as early as 1839 ...

  7. Energy Efficient Task Light

    DEFF Research Database (Denmark)

    Logadottir, Asta; Ardkapan, Siamak Rahimi; Johnsen, Kjeld;

    2014-01-01

    the light source as far from the bottom edge as possible. The main results of the project show opportunities for energy savings in an office environment by reducing the installed power for the general lighting by applying a task light with a wide light distribution across the desk area , providing high...... and thereby a reduction in installed power for general lighting of about 40 % compared to the way illuminance levels are designed in an office environment in Denmark today. This lighting strategy is useful when the placement of the task area is not defined in the space before the lighting is design ed...... and the strategy also allows for the task area to be redefined in the space . The task lighting follows the task area as the developed task light is designed to be placed on the desktop of an office desk. The work carried out within this project is the architectural design of the task light, the optical design...

  8. Coordination and Multi-Tasking Using EMT

    OpenAIRE

    Rabinovich, Zinovi; Pochter, Nir; Rosenschein, Jeffrey S.

    2008-01-01

    We introduce a multi-model variant of the EMT-based control algorithm. The new algorithm, MM-EMT, is capable of balancing several control tasks expressed using separate dynamic models with a common action space. Such multiple models are common in both single-agent environments, when the agent has multiple tasks to achieve, and in team activities, when agent actions affect both the local agent’s task as well as the overall team’s coordination. To demonstrate the behaviour that MM-EMT engenders...

  9. 考虑任务排序策略的舰船建造车间虚拟制造单元动态调度%Virtual manufacturing cell dynamic scheduling of ship construction workshop considering the task sorting strategy

    Institute of Scientific and Technical Information of China (English)

    韩文民; 孙晓梅; 孔鹏; 吕洁

    2014-01-01

    为提高舰船制造系统作业调度的柔性和效率,从车间层的作业计划角度出发,研究周期驱动条件下的虚拟制造单元多阶段动态调度问题并构建了动态调度数学模型。模型中考虑了加工任务动态需求、设备加工能力、负荷平衡、同类设备有多台的情况且提出共享资源协调排序策略,以实现最大完工时间和总物料运输距离之和最小化的目标。运用改进蚁群算法与启发式规则的混合算法进行求解。通过某船厂的实际生产数据验证了虚拟单元动态调度方法的可行性和有效性。%In order to improve the flexibility and efficiency of shipbuilding production scheduling system and develop shop floor short - term plans, virtual manufacturing cell multi-period dynamic scheduling model was established in condition of cycle driving mechanism. The model incorporated parameters of the processing task dynamic demand, equipment processing capability, load balance, and similar equipments have multiple; and put forward sharing resources coordination sorting strategy. The objective is to minimize completion time and the total materials and components travelling distance incurred. A hybrid algorithm, based on the improved ant colony algorithm and heuristic rules was proposed to solve the complex scheduling problem. Actual production data proved that the proposed approach was feasible and effective.

  10. Transport Task Force Leadership, Task 4

    International Nuclear Information System (INIS)

    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

  11. Brain network adaptability across task states.

    Directory of Open Access Journals (Sweden)

    Elizabeth N Davison

    2015-01-01

    Full Text Available Activity in the human brain moves between diverse functional states to meet the demands of our dynamic environment, but fundamental principles guiding these transitions remain poorly understood. Here, we capitalize on recent advances in network science to analyze patterns of functional interactions between brain regions. We use dynamic network representations to probe the landscape of brain reconfigurations that accompany task performance both within and between four cognitive states: a task-free resting state, an attention-demanding state, and two memory-demanding states. Using the formalism of hypergraphs, we identify the presence of groups of functional interactions that fluctuate coherently in strength over time both within (task-specific and across (task-general brain states. In contrast to prior emphases on the complexity of many dyadic (region-to-region relationships, these results demonstrate that brain adaptability can be described by common processes that drive the dynamic integration of cognitive systems. Moreover, our results establish the hypergraph as an effective measure for understanding functional brain dynamics, which may also prove useful in examining cross-task, cross-age, and cross-cohort functional change.

  12. A Brief Analysis of Communication Tasks in Task- based Teaehing

    Institute of Scientific and Technical Information of China (English)

    Xu Xiaoying

    2011-01-01

    Task -Based Language Teaching (TBLT) aims at proving opportunities for the learners to experiment with and explore both spoken and written language through learning activities. This passage further exam if the following four communicative tasks jigsaw tasks, role - play tasks, problem solving tasks, and information gap tasks can assist classroom learning.

  13. Dynamic Task Scheduling on Multicore Automotive ECUs

    OpenAIRE

    Geetishree Mishra; K.S.Gurumurthy

    2014-01-01

    Automobile manufacturers are controlled by stringen t govt. regulations for safety and fuel emissions a nd motivated towards adding more advanced features and sophisticated applications to the existing electro nic system. Ever increasing customer’s demands for high level of comfort also necessitate providing even m ore sophistication in vehicle electronics system. All t hese, directly make the vehicle software system mor e co...

  14. What Task Designers Do.

    Science.gov (United States)

    Johnson, Keith

    2000-01-01

    Describes a research project that is concerned with the design procedures followed by those engaged in designing pedagogic tasks for use in classrooms. Focuses on the part of the project that involves actual observation of designers in the process of developing one specific task for class use. Findings are presented under three headers: control…

  15. Supporting complex search tasks

    DEFF Research Database (Denmark)

    Gäde, Maria; Hall, Mark; Huurdeman, Hugo;

    2015-01-01

    There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks......, is fragmented at best. The workshop addressed the many open research questions: What are the obvious use cases and applications of complex search? What are essential features of work tasks and search tasks to take into account? And how do these evolve over time? With a multitude of information, varying from...... introductory to specialized, and from authoritative to speculative or opinionated, when to show what sources of information? How does the information seeking process evolve and what are relevant differences between different stages? With complex task and search process management, blending searching, browsing...

  16. Board Task Performance

    DEFF Research Database (Denmark)

    Minichilli, Alessandro; Zattoni, Alessandro; Nielsen, Sabina;

    2012-01-01

    identify three board processes as micro-level determinants of board effectiveness. Specifically, we focus on effort norms, cognitive conflicts and the use of knowledge and skills as determinants of board control and advisory task performance. Further, we consider how two different institutional settings...... influence board tasks, and how the context moderates the relationship between processes and tasks. Our hypotheses are tested on a survey-based dataset of 535 medium-sized and large industrial firms in Italy and Norway, which are considered to substantially differ along legal and cultural dimensions....... The findings show that: (i) Board processes have a larger potential than demographic variables to explain board task performance; (ii) board task performance differs significantly between boards operating in different contexts; and (iii) national context moderates the relationships between board processes...

  17. Task Description Language

    Science.gov (United States)

    Simmons, Reid; Apfelbaum, David

    2005-01-01

    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.

  18. Supporting complex search tasks

    DEFF Research Database (Denmark)

    Gäde, Maria; Hall, Mark; Huurdeman, Hugo;

    2015-01-01

    , and recommendations, and supporting exploratory search to sensemaking and analytics, UI and UX design pose an overconstrained challenge. How do we know that our approach is any good? Supporting complex search task requires new collaborations across the whole field of IR, and the proposed workshop will bring together......There is broad consensus in the field of IR that search is complex in many use cases and applications, both on the Web and in domain specific collections, and both professionally and in our daily life. Yet our understanding of complex search tasks, in comparison to simple look up tasks......, is fragmented at best. The workshop addressed the many open research questions: What are the obvious use cases and applications of complex search? What are essential features of work tasks and search tasks to take into account? And how do these evolve over time? With a multitude of information, varying from...

  19. 运动声源的双耳录音声像定位效果分析%Spatial Localization Performances of Moving Sound in Binaural Recording

    Institute of Scientific and Technical Information of China (English)

    仝欣; 齐娜

    2015-01-01

    分析了不同运动方式下双耳录音的声像定位效果,录音采用的声学头模是由中国传媒大学自行研制的,头部尺寸符合中国人的平均生理参数。共录制、评价了三种声源状态下的定位效果:静止、射线运动和横向运动。主观评价实验结果表明运动声源有助于将声像定位在头外,在一定程度上改善了头中定位效应,但声源运动并不能有效地减少声像前后混淆率和上下混淆率。此外,不同的声源运动方式也影响着声像定位的正确率,横向运动比射线运动的声像方向定位正确率高9%。%The spatial localization performance with different moving patterns in binaural recording was analyzed. The acoustical dummy head used here was designed by Communication University of China. The size of the dummy head kept meeting the national standards and was in accordance with the average phys-iological parameters of Chinese people. Three kinds of sound sources were recorded and analyzed:station-ary sound,radial-straightline-movement sound and crosswise-straightline-movement sound. The re-sult of subjective listening test showed that the movement of the sound contributes to localize the sound image outside the head and weaken inside-the-head effect to some extent. However,the movement of the sound cannot reduce the front-back confusion and up-down confusion effectively. Besides,different movement styles of sound source will affect the localization accuracy,and the rate of accuracy was 9%higher when sound source moving linearly in crosswise direction than in radial direction.

  20. Task-baseret kommunikativ sprogundervisning

    DEFF Research Database (Denmark)

    Pedersen, Michael Svendsen

    2015-01-01

    Definition af task-baseret sprogundervisning, kriterier for task. Forskning i Second Language Acquisition med brug af task, tilrettelæggelse af task-baseret kommunikativ undervisning. Begrænsninger i og perspektiver for videreudvikling af task-baseret sprogundervising-......Definition af task-baseret sprogundervisning, kriterier for task. Forskning i Second Language Acquisition med brug af task, tilrettelæggelse af task-baseret kommunikativ undervisning. Begrænsninger i og perspektiver for videreudvikling af task-baseret sprogundervising-...

  1. Studying Different Tasks of Implicit Learning across Multiple Test Sessions Conducted on the Web

    OpenAIRE

    Sævland, Werner; Norman, Elisabeth

    2016-01-01

    Implicit learning is usually studied through individual performance on a single task, with the most common tasks being the Serial Reaction Time (SRT) task, the Dynamic System Control (DSC) task, and Artificial Grammar Learning (AGL). Few attempts have been made to compare performance across different implicit learning tasks within the same study. The current study was designed to explore the relationship between performance on the DSC Sugar factory task and the Alternating Serial Reaction Tim...

  2. Classroom Interactions in a Cooperative Translation Task

    Directory of Open Access Journals (Sweden)

    Hui chuan Wang

    2013-03-01

    Full Text Available For the past decade, translation learning has become one of the main foci for university language students in Taiwan. However, many studies have shown that translation teachers tend to adopt traditional teaching methods without considering class dynamics and student interactions. This paper therefore looks into the interactions in the researcher’s designed cooperative translation task, the Cooperative Translation Task, to see how these interactions helped or hindered students’ translation learning. A small class of 25 translation students and two translation teachers were participants. Videotaping and interviews were conducted in order to investigate the interaction modes and student participants’ perspectives toward each interaction mode. Six interaction modes were found in this task: within group, between group, translator group and comment-giver group, instructor and students, guest teacher and students, and instructor and guest teacher. Based on the results and participants’ responses, suggested teaching guidelines are provided.Keywords: classroom interaction, interaction mode, Cooperative Translation Task, translation teaching

  3. Organizing Core Tasks

    DEFF Research Database (Denmark)

    Boll, Karen

    Civil servants conduct the work which makes welfare states functions on an everyday bases: Police men police, school teachers teach, and tax inspectors inspect. Focus in this paper is on the core tasks of tax inspectors. The paper argues that their core task of securing the collection of revenue...... has remained much the same within the last 10 years. However, how the core task has been organized has changed considerable under the influence of various “organizing devices”. The paper focusses on how organizing devices such as risk assessment, output-focus, effect orientation, and treatment...... projects influence the organization of core tasks within the tax administration. The paper shows that the organizational transformations based on the use of these devices have had consequences both for the overall collection of revenue and for the employees’ feeling of “making a difference”. All in all...

  4. Beta频段双耳差频声刺激对大脑生理状态的影响%Effects of Beta Band Binaural Beats on Brain Physiological Status

    Institute of Scientific and Technical Information of China (English)

    张露; 焦学军; 高翔; 陈润格; 王学民; 綦宏志; 明东; 何峰; 周鹏

    2016-01-01

    随着载人航天事业的快速发展,航天员的大脑状态调控以及警觉度提高技术成为航天人因工程研究热点和难点问题之一。为了探究beta段差频声刺激对大脑状态的调控作用,在N⁃back任务过程中进行了beta段双耳差频声刺激组和对照组平行实验。根据实验中的N⁃back反应时和正确率分类,划分成三组对beta频段差频声刺激敏感程度不同的受试人群,分别是敏感组、中间组和非敏感组,分析beta频段功率谱密度差值、( alpha+theta)/beta的比值、非线性特征样本熵和互信息脑网络等特征。结果表明,双耳差频声刺激的脑区激活存在个体差异性,对声刺激敏感的受试者,差频刺激下,脑电功率谱中的beta频段在右颞区能量增强( T4,p<0�005),T3电极处三组人群(alpha+theta)/beta比值具有显著差异性,敏感人群中刺激组样本熵值比对照组高10�53%,且互信息集群系数最高(0�971),脑网络信息交流增强,这说明差频声刺激能改变大脑的生理状态,在提高航天员的注意力和警觉度、对抗脑力疲劳方面具有应用前景。%With the rapid development of manned space program, exploring new methods to improve the brain physiological status effectively and rapidly is one of the hottest researches in the area of space human factors engineering. Binaural beat is a kind of acoustic stimulus mode, which is closely related to the features of human brain waves, mental state and mood. In order to explore its correla⁃tion with the brain status, two sets of parallel experiments were designed for the beta band binaural frequency stimulus group and the contrast group. According to the reaction time and accuracy rate of N⁃back, subjects who had different sensitive degree to sound stimulus were classified into three dif⁃ferent groups:sensitivity group, middle group and non⁃sensitivity group. In the

  5. Acoustic trauma slows AMPA receptor‐mediated EPSCs in the auditory brainstem, reducing GluA4 subunit expression as a mechanism to rescue binaural function

    Science.gov (United States)

    Pilati, Nadia; Linley, Deborah M.; Selvaskandan, Haresh; Uchitel, Osvaldo; Hennig, Matthias H.; Kopp‐Scheinpflug, Cornelia

    2016-01-01

    prehearing animals to 2.6 ± 0.4 ms in adults, as GluN2C expression increased. In vivo induction of AT at around P20 disrupted IPSC and EPSC integration in the LSO, so that 1 week later the AMPA receptor (AMPAR)‐EPSC decay was slowed and mRNA for GluA1 increased while GluA4 decreased. In contrast, GlyR IPSC and NMDAR‐EPSC decay times were unchanged. Computational modelling confirmed that matched IPSC and EPSC kinetics are required to generate mature interaural level difference functions, and that longer‐lasting EPSCs compensate to maintain binaural function with raised auditory thresholds after AT. We conclude that LSO excitatory and inhibitory synaptic drive matures to identical time‐courses, that AT changes synaptic AMPARs by expression of subunits with slow kinetics (which recover over 2 months) and that loud sounds reversibly modify excitatory synapses in the brain, changing synaptic function for several weeks after exposure. PMID:27104476

  6. Recurrent Spiking Networks Solve Planning Tasks

    Science.gov (United States)

    Rueckert, Elmar; Kappel, David; Tanneberg, Daniel; Pecevski, Dejan; Peters, Jan

    2016-02-01

    A recurrent spiking neural network is proposed that implements planning as probabilistic inference for finite and infinite horizon tasks. The architecture splits this problem into two parts: The stochastic transient firing of the network embodies the dynamics of the planning task. With appropriate injected input this dynamics is shaped to generate high-reward state trajectories. A general class of reward-modulated plasticity rules for these afferent synapses is presented. The updates optimize the likelihood of getting a reward through a variant of an Expectation Maximization algorithm and learning is guaranteed to convergence to a local maximum. We find that the network dynamics are qualitatively similar to transient firing patterns during planning and foraging in the hippocampus of awake behaving rats. The model extends classical attractor models and provides a testable prediction on identifying modulating contextual information. In a real robot arm reaching and obstacle avoidance task the ability to represent multiple task solutions is investigated. The neural planning method with its local update rules provides the basis for future neuromorphic hardware implementations with promising potentials like large data processing abilities and early initiation of strategies to avoid dangerous situations in robot co-worker scenarios.

  7. Performing Task Integration

    DEFF Research Database (Denmark)

    Elkjaer, Bente; Nickelsen, Niels Christian Mossfeldt

    by shared goals and knowledge as well as mutual respect and frequent, timely, accurate and problem-solving ways of communication with the purpose of dealing with the tasks at hand in an integrated way. We introduce and discuss relational coordination theory through a case-study within public healthcare....... Here cross-professional coordination of work was done by scheduled communication twice a day. When we proposed a way for further integration of tasks through an all-inclusive team organization, we were met with resistance. We use the study to discuss whether relational coordination theory is able to do...

  8. Algebra task & drill sheets

    CERN Document Server

    Reed, Nat

    2011-01-01

    For grades 3-5, our State Standards-based combined resource meets the algebraic concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are opportunities for problem-solving, patterning, algebraic graphing, equations and determining averages. The combined task & drill sheets

  9. Algebra task & drill sheets

    CERN Document Server

    Reed, Nat

    2011-01-01

    For grades 6-8, our State Standards-based combined resource meets the algebraic concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are opportunities for problem-solving, patterning, algebraic graphing, equations and determining averages. The combined task & drill sheets

  10. Biomedical applications engineering tasks

    Science.gov (United States)

    Laenger, C. J., Sr.

    1976-01-01

    The engineering tasks performed in response to needs articulated by clinicians are described. Initial contacts were made with these clinician-technology requestors by the Southwest Research Institute NASA Biomedical Applications Team. The basic purpose of the program was to effectively transfer aerospace technology into functional hardware to solve real biomedical problems.

  11. Task 1 quarternary tectonics

    Energy Technology Data Exchange (ETDEWEB)

    Bell, J.W.

    1994-12-31

    Activities on the task of quarternary tectonics for the Yucca Mountain Site investigations are described. Technical topics include: A preliminary reveiw of Bare Mountain Trench; A preliminary detailed lineament map of the Southwestern part of the proposed repository; A discussion on the 1994 Double Spring Flat, Nevada earthquake; and evidence for temporal clustering.

  12. A Daunting Task Still

    Institute of Scientific and Technical Information of China (English)

    ZHANG ZHIPING

    2010-01-01

    @@ Despite steady economic growth for three decades, China is still a developing country facing daunting poverty alleviation tasks. According to the poverty line of 1,196 yuan ($176) per capita net income in a year set in March 2009, the country still has a poverty population of more than 40 million, mainly living in rural areas.

  13. The sequential logic model to solve the multi-Agent dynamic cooperative tasks of complex self-adaptive system%复杂自适应系统的MAS动态协作任务求解时序逻辑模型

    Institute of Scientific and Technical Information of China (English)

    蒋伟进; 张莲梅; 史德嘉

    2012-01-01

    借鉴组织学思想将自适应系统中的自主运行单元抽象为Agent,把复杂自适应系统视为多Agent组织,从时间和状态角度对复杂动态系统的行为进行描述,提出了基于时序活动逻辑的多Agent动态协作任务求解自适应机制和构造模型;分析了任务求解BDI Agent的信念、愿望、意图的产生过程和实现方法,建立了协商推理的语义规则和行为规则,给出了协作群组的选择算法.并从任务求解Agent的心智变化角度,描述了动态协作任务求解模型实现的六个阶段:任务动态分配、协作意愿产生、协作群体生成、共同计划制定、协作群体行动和结果评估.通过在MAGE等平台上实验和仿真测试,验证了方法的可行性和有效性.%Solving dynamic complex problem is difficult in the theory and applied research of artificial intelligence and complex adaptive systems. Idea from histology is that the auto-run unit in self-adaptive system is abstracted to be Agent, the complex adaptive system is considered as a multi-Agent tissue. The behavior of complex dynamic systems in time and space is described. The adaptive mechanisms and structure model of solving multi-Agent dynamic cooperative tasks based on sequential active logic are proposed. The production process and realization of BDI belief, desire, intention of solving task are analyzed. The semantic rules and action rules of cooperative deduction is builded. The selection algorithm of cooperative groups is given. From the mind change of task solving Agent, the paper describes the six stages to realize the solving model of dynamic cooperative tasks. The six stages are dynamic allocation of tasks, collaboration will produce, generate collaborative groups, common planning making, collaborative groups action and evaluation of results. Experiments and simulation on MAGE and other platforms prove the feasibility and effectiveness of our proposed approaches.

  14. PRI: An Periodically Receiver-Initiated Task Scheduling Algorithm

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Task scheduling is a key problem for the distributed computation. This thesis analyzes receiver-initiated(RI) task scheduling algorithm, finds its weakness and presents an improved algorithm-PRI algorithm. This algorithm schedules the concurrent tasks onto network of workstation dynamically at runtime, and initiates task scheduling by the node of low load. The threshold on each node can be modified according to the system information which is periodically detected. Meanwhile, the detecting period can be adjusted in terms of the change of the system state. The result of the experiments shows that the PRI algorithm is superior to the RI algorithm.

  15. Force-Field Compensation in a Manual Tracking Task

    OpenAIRE

    Valentina Squeri; Lorenzo Masia; Maura Casadio; Pietro Morasso; Elena Vergaro

    2010-01-01

    This study addresses force/movement control in a dynamic "hybrid" task: the master sub-task is continuous manual tracking of a target moving along an eight-shaped Lissajous figure, with the tracking error as the primary performance index; the slave sub-task is compensation of a disturbing curl viscous field, compatibly with the primary performance index. The two sub-tasks are correlated because the lateral force the subject must exert on the eight-shape must be proportional to the longitudina...

  16. Multi-task connectivity reveals flexible hubs for adaptive task control

    Science.gov (United States)

    Cole, Michael W.; Reynolds, Jeremy R.; Power, Jonathan D.; Repovs, Grega; Anticevic, Alan; Braver, Todd S.

    2013-01-01

    Extensive evidence suggests the human ability to adaptively implement a wide variety of tasks is preferentially due to the operation of a fronto-parietal brain network. We hypothesized that this network’s adaptability is made possible by ‘flexible hubs’ – brain regions that rapidly update their pattern of global functional connectivity according to task demands. We utilized recent advances in characterizing brain network organization and dynamics to identify mechanisms consistent with the flexible hub theory. We found that the fronto-parietal network’s brain-wide functional connectivity pattern shifted more than other networks’ across a variety of task states, and that these connectivity patterns could be used to identify the current task. Further, these patterns were consistent across practiced and novel tasks, suggesting reuse of flexible hub connectivity patterns facilitates adaptive (novel) task performance. Together, these findings support a central role for fronto-parietal flexible hubs in cognitive control and adaptive implementation of task demands generally. PMID:23892552

  17. Task analysis and support for problem solving tasks

    International Nuclear Information System (INIS)

    This paper is concerned with Task Analysis as the basis for ergonomic design to reduce human error rates, rather than for predicting human error rates. Task Analysis techniques usually provide a set of categories for describing sub tasks, and a framework describing the relations between sub-tasks. Both the task type categories and their organisation have implications for optimum interface and training design. In this paper, the framework needed for considering the most complex tasks faced by operators in process industries is discussed such as fault management in unexpected situations, and what is likely to minimise human error in these circumstances. (author)

  18. The Nexus task-parallel runtime system

    Energy Technology Data Exchange (ETDEWEB)

    Foster, I.; Tuecke, S. [Argonne National Lab., IL (United States); Kesselman, C. [Caltech, Pasadena, CA (United States). Beckman Institute

    1994-12-31

    A runtime system provides a parallel language compiler with an interface to the low-level facilities required to support interaction between concurrently executing program components. Nexus is a portable runtime system for task-parallel programming languages. Distinguishing features of Nexus include its support for multiple threads of control, dynamic processor acquisition, dynamic address space creation, a global memory model via interprocessor references, and asynchronous events. In addition, it supports heterogeneity at multiple levels, allowing a single computation to utilize different programming languages, executables, processors, and network protocols. Nexus is currently being used as a compiler target for two task-parallel languages: Fortran M and Compositional C++. In this paper, we present the Nexus design, outline techniques used to implement Nexus on parallel computers, show how it is used in compilers, and compare its performance with that of another runtime system.

  19. Effects of noise and task loading on a communication task loading on a communication task

    Science.gov (United States)

    Orrell, Dean H., II

    Previous research had shown the effect of noise on a single communication task. This research has been criticized as not being representative of a real world situation since subjects allocated all of their attention to only one task. In the present study, the effect of adding a loading task to a standard noise-communication paradigm was investigated. Subjects performed both a communication task (Modified Rhyme Test; House et al. 1965) and a short term memory task (Sternberg, 1969) in simulated levels of aircraft noise (95, 105 and 115 dB overall sound pressure level (OASPL)). Task loading was varied with Sternberg's task by requiring subjects to memorize one, four, or six alphanumeric characters. Simulated aircraft noise was varied between levels of 95, 105 and 115 dB OASPL using a pink noise source. Results show that the addition of Sternberg's task and little effect on the intelligibility of the communication task while response time for the communication task increased.

  20. Mobile Thread Task Manager

    Science.gov (United States)

    Clement, Bradley J.; Estlin, Tara A.; Bornstein, Benjamin J.

    2013-01-01

    The Mobile Thread Task Manager (MTTM) is being applied to parallelizing existing flight software to understand the benefits and to develop new techniques and architectural concepts for adapting software to multicore architectures. It allocates and load-balances tasks for a group of threads that migrate across processors to improve cache performance. In order to balance-load across threads, the MTTM augments a basic map-reduce strategy to draw jobs from a global queue. In a multicore processor, memory may be "homed" to the cache of a specific processor and must be accessed from that processor. The MTTB architecture wraps access to data with thread management to move threads to the home processor for that data so that the computation follows the data in an attempt to avoid L2 cache misses. Cache homing is also handled by a memory manager that translates identifiers to processor IDs where the data will be homed (according to rules defined by the user). The user can also specify the number of threads and processors separately, which is important for tuning performance for different patterns of computation and memory access. MTTM efficiently processes tasks in parallel on a multiprocessor computer. It also provides an interface to make it easier to adapt existing software to a multiprocessor environment.

  1. Rostering and Task Scheduling

    DEFF Research Database (Denmark)

    Dohn, Anders Høeg

    In a modern society, manpower can be both a scarce and an expensive resource. Skilled personnel is usually in high demand and accounts for a significant part of total expenses in many companies. When the work is divided in shifts, a roster is compiled to allocate these to the employees. The roste......In a modern society, manpower can be both a scarce and an expensive resource. Skilled personnel is usually in high demand and accounts for a significant part of total expenses in many companies. When the work is divided in shifts, a roster is compiled to allocate these to the employees...... as possible to the available staff, while respecting various requirements and rules and while including possible transportation time between tasks. This thesis presents a number of industrial applications in rostering and task scheduling. The applications exist within various contexts in health care...... to scheduling problems with temporal dependencies between tasks. However, these problems appear in various contexts and with different properties. A group of the problems considered are related to vehicle routing problems, where transportation and time windows are important factors that must be accounted for...

  2. Urban task force

    Directory of Open Access Journals (Sweden)

    Grubović Ljiljana V.

    2002-01-01

    Full Text Available The Urban Task Force Report has brought to our attention, that English towns and cities today require a new renaissance. The comprehensive planning has retarded urban living (Urban Renaissance, Sharing the Vision 01.99, 1999. Forty percent of inner-urban housing stock is subsidized 'social' housing. A review of the demographic and development trends have lead to the UK Government’s new urban policy that prioritizes the regeneration of towns and cities by building on recycled urban land and protecting the countryside. As result, Urban Task Force (UTF was founded the with the following aims To identify causes of urban decline in England; To recommend practical solutions how to bring people back into cities; To establish a new vision for urban regeneration based on the principles of design excellence, social well being and environmental responsibility within a viable economic and legislative framework (Urban Task Force, 1999:1. This paper represents the analysis of the economic and political effects of the program and its viability.

  3. Gap Task Force

    CERN Multimedia

    Lissuaer, D

    One of the more congested areas in the ATLAS detector is the GAP region (the area between the Barrel Calorimeter and the End Cap calorimeter) where Inner Detector services, LAr Services and some Tile services all must co-habitat in a very limited area. It has been clear for some time that the space in the GAP region is not sufficient to accommodate all that is needed. In the last few month additional problems of routing all the services to Z=0 have been encountered due to the very limited space between the Tile Calorimeter and the first layer of Muon chambers. The Technical Management Board (TMB) and the Executive Board (EB) decided in the middle of March to establish a Task Force to look at this problem and come up with a solution within well-specified guidelines. The task force consisted of experts from the ID, Muon, Liquid Argon and Tile systems in addition to experts from the Technical Coordination team and the Physics coordinator. The task force held many meetings and in general there were some very l...

  4. What's the Problem? Familiarity Working Memory, and Transfer in a Problem-Solving Task.

    Science.gov (United States)

    Kole, James A; Snyder, Hannah R; Brojde, Chandra L; Friend, Angela

    2015-01-01

    The contributions of familiarity and working memory to transfer were examined in the Tower of Hanoi task. Participants completed 3 different versions of the task: a standard 3-disk version, a clothing exchange task that included familiar semantic content, and a tea ceremony task that included unfamiliar semantic content. The constraints on moves were equivalent across tasks, and each could be solved with the same sequence of movements. Working memory demands were manipulated by the provision of a (static or dynamic) visual representation of the problem. Performance was equivalent for the standard Tower of Hanoi and clothing exchange tasks but worse for the tea ceremony task, and it decreased with increasing working memory demands. Furthermore, the standard Tower of Hanoi task and clothing exchange tasks independently, additively, and equivalently transferred to subsequent tasks, whereas the tea ceremony task did not. The results suggest that both familiarity and working memory demands determine overall level of performance, whereas familiarity influences transfer. PMID:26255436

  5. Integrated Teaching Tasks as part of Studying Activities

    Directory of Open Access Journals (Sweden)

    Luis Alberto Mass Sosa

    2011-02-01

    Full Text Available In spite of the known didactic value of integrated teaching tasks, they are not appropriately used neither individually, nor in groups, due to the lack of an specific integrating didactic and proposals that work as methodological tools. A bibliographic revision was conducted to clarify the role of integrated teaching tasks as part of the structure of studying activities and to highlight some aspects that could make easier the design, implementation and control of such tasks. It was possible to identify that integrated teaching tasks are part of the structure of studying activities to the level of partial objectives that students should meet. Among the aspects that make the design, implementation and control easier we may find: role as guideline, integrative approach and systematization of contents, systemic approach of the teaching tasks, links between teaching contents and practical life (theory and practice, care for diversity, integrated teaching tasks in groups and systemic, collective and dynamic methodologic work.

  6. The implementation of dynamite: an environment for migrating PVM tasks

    NARCIS (Netherlands)

    K.A. Iskra; F. van der Linden; Z.W. Hendrikse; B.J. Overeinder; G.D. van Albada; P.M.A. Sloot

    2000-01-01

    Parallel programming on clusters of workstations is increasingly attractive, but dynamic load balancing is needed to make efficient use of the available resources. Dynamite provides dynamic load balancing for PVM applications running under Linux and Solaris. It supports migration of individual tasks

  7. Calorimetry Task Force Report

    CERN Document Server

    Abdullin, Salavat; Banerjee, Sunanda; Beauceron, Stephanie; Beaudette, Florian; Bhatti, Anwar; Chlebana, Frank; Cossutti, Fabio; Hirschauer, James; Ivanchenko, V; Jang, Dong Wook; Jun, Soon Yung; Kunori, Shuichi; Kroeger, Rob; Liu, Yanwen; Moeller, Anthony; Paulini, Manfred; Piperov, Stefan; Rahmat, Rahmat; Rovelli, Chiara; Safronov, Grigory; Sharma, Seema; Spiropulu, Maria; Yetkin, Taylan

    2010-01-01

    In this note we summarize the progress made by the calorimeter simulation task force (CaloTF) over the past year. The CaloTF was established in February 2008 in order to understand and reconcile the discrepancies observed between the CMS calorimetry simulation and test beam data recorded during 2004 and 2006. The simulation has been significantly improved by using a newer version of Geant4 and an improved physics list for the full CMS detector simulation. Simulation times have been reduced by introducing flexible parameterizations to describe showering in the calorimeter (using a Gflash-like approach) which have been tuned to the test beam data.

  8. Quarternary tectonics, Task 1

    Energy Technology Data Exchange (ETDEWEB)

    Bell, J.W.

    1993-09-30

    Activities conducted for the evaluation of the geology and seismotectonics stability of Yucca Mountain as a potential site for the underground disposal of high-level radioactive wastes continued. Tasks concerned with quaternary tectonics include: scheduling of photography of Little Skull Mountain area; the collection and dating of rock varnish samples from the 1932 Cedar Mountain earthquake area for carbon 14 AMS and cation-ratio analysis; collection of samples for thermoluminescence dating from the 1932 Cedar Mountain earthquake area; mapping of the northern area of Crater Flat; and surveying of the May 17, 1993 Eureka the Valley earthquake area.

  9. Social Pressures and Task Performance

    OpenAIRE

    Shearer, Greg

    2013-01-01

    Previous research has demonstrated the impact of the actions of others on task performance – citing that both social acceptance and ostracism can increase task performance (Lustenberger & Jagacinski, 2010; Jamieson et. al., 2010). In this study, the relationship between social inclusion/ostracism and performance on a verbal comprehension task is investigated in an attempt to discover which is more potent in influencing task performance. Two forms of social conditioning are used; face-to-face ...

  10. Reverse-Engineering Communication Tasks

    Science.gov (United States)

    Lamber, Craig

    2004-01-01

    This article introduces an approach to planning sequences of communication tasks that require learners to become personally involved in their learning. By drawing on their own ideas and experiences, as a product of earlier tasks in a given sequence, learners generate the content and resource material on which subsequent tasks operate. The article…

  11. Skill Components of Task Analysis

    Science.gov (United States)

    Adams, Anne E.; Rogers, Wendy A.; Fisk, Arthur D.

    2013-01-01

    Some task analysis methods break down a task into a hierarchy of subgoals. Although an important tool of many fields of study, learning to create such a hierarchy (redescription) is not trivial. To further the understanding of what makes task analysis a skill, the present research examined novices' problems with learning Hierarchical Task…

  12. AMU NEXRAD Exploitation Task

    Science.gov (United States)

    Lambert, Winifred C.; Wheeler, Mark M.

    1997-01-01

    This report documents the results of the Applied Meteorology Unit's NEXRAD Exploitation Task. The objectives of this task are to determine what radar signatures are present prior to and at the time of convection initiation, and to determine radar signatures which will help distinguish whether the ensuing convection will become severe. Radar data from the WSR-88D radar located at NWS Melbourne (WSR-88D/KMLB) were collected between June and September 1995, and 16 convective case studies were analyzed for which the radar was operating during the entire period of interest. All WSR-88D/KMLB products were scrutinized for their utility in detecting convection initiation and severe storm signatures. Through process of elimination, it was found that the 0.5 deg reflectivity product with the lowest reflectivity values displayed is the best product to monitor for convection initiation signatures. Seven meteorological features associated with the initiation of deep convection were identified: the Merritt Island and Indian River convergence zones, interlake convergence, horizontal convective rolls, the sea breeze, storm outflow boundaries, and fires. Their reflectivity values ranged from -5 to 20 dBZ. Of the three severe weather phenomena (winds greater than or equal to 50 kts, tornado, 3/4 inch hail), high wind events due to microbursts were most common in the data set. It was found that the values and trends of composite reflectivity, vertically integrated liquid, and core aspect ratio were key indicators of the potential of a cell to produce a microburst. The data were not analyzed for the other two severe weather phenomena because they rarely occurred during the data collection period. This report also includes suggestions for new WSR-88D products, summaries of ongoing research aimed at creating new products, and explicit recommended procedures for detecting convection initiation and severe storm signatures in the radar data using the currently available technology.

  13. Performance in Tangible and in Cognitive Stock-Flow Tasks. Closer Than Expected

    NARCIS (Netherlands)

    Strohhecker, J.; Grössler, A.

    2015-01-01

    - Background - Most research in the area of dynamic decision making in general and stock-flow failures in particular is conducted with the help of computerized simulations as task environments or paper-based tasks of simple dynamic systems. - Purpose - The purpose of this article is to investigate i

  14. Real-time multi-task operators support system

    International Nuclear Information System (INIS)

    The development in computer software and hardware technology and information processing as well as the accumulation in the design and feedback from Nuclear Power Plant (NPP) operation created a good opportunity to develop an integrated Operator Support System. The Real-time Multi-task Operator Support System (RMOSS) has been built to support the operator's decision making process during normal and abnormal operations. RMOSS consists of five system subtasks such as Data Collection and Validation Task (DCVT), Operation Monitoring Task (OMT), Fault Diagnostic Task (FDT), Operation Guideline Task (OGT) and Human Machine Interface Task (HMIT). RMOSS uses rule-based expert system and Artificial Neural Network (ANN). The rule-based expert system is used to identify the predefined events in static conditions and track the operation guideline through data processing. In dynamic status, Back-Propagation Neural Network is adopted for fault diagnosis, which is trained with the Genetic Algorithm. Embedded real-time operation system VxWorks and its integrated environment Tornado II are used as the RMOSS software cross-development. VxGUI is used to design HMI. All of the task programs are designed in C language. The task tests and function evaluation of RMOSS have been done in one real-time full scope simulator. Evaluation results show that each task of RMOSS is capable of accomplishing its functions. (authors)

  15. Task swapping networks in distributed systems

    CERN Document Server

    Kim, Dohan

    2011-01-01

    In this paper we propose task swapping networks for task reassignments by using task swappings in distributed systems. Some classes of task reassignments are achieved by using iterative local task swappings between software agents in distributed systems. We use group-theoretic methods to find a minimum-length sequence of adjacent task swappings needed from a source task assignment to a target task assignment in a task swapping network of several well-known topologies.

  16. What are task-sets: a single, integrated representation or a collection of multiple control representations?

    Directory of Open Access Journals (Sweden)

    Dragan eRangelov

    2013-09-01

    Full Text Available Performing two randomly alternating tasks typically results in higher reaction times (RTs following a task switch, relative to a task repetition. These task switch costs (TSC reflect processes of switching between control settings for different tasks. The present study investigated whether task sets operate as a single, integrated representation or as an agglomeration of relatively independent components. In a cued task switch paradigm, target detection (present/absent and discrimination (blue/green/right-/left-tilted tasks alternated randomly across trials. The target was either a color or an orientation singleton among homogeneous distractors. Across two trials, the task and target-defining dimension repeated or changed randomly. For task switch trials, agglomerated task sets predict a difference between dimension changes and repetitions: joint task and dimension switches require full task set reconfiguration, while dimension repetitions permit re-using some control settings from the previous trial. By contrast, integrated task sets always require full switches, predicting dimension repetition effects (DREs to be absent across task switches. RT analyses showed significant DREs across task switches as well as repetitions supporting the notion of agglomerated task sets. Additionally, two event-related potentials (ERP were analyzed: the Posterior-Contralateral-Negativity (PCN indexing spatial selection dynamics, and the Sustained-Posterior-Contralateral-Negativity (SPCN indexing post-selective perceptual/semantic analysis. Significant DREs across task switches were observed for both the PCN and SPCN components. Together, DREs across task switches for RTs and two functionally distinct ERP components suggest that re-using control settings across different tasks is possible. The results thus support the ‘agglomerated-task-set’ hypothesis, and are inconsistent with ‘integrated task sets’.

  17. Task Prioritization in Dual-Tasking: Instructions versus Preferences

    Science.gov (United States)

    Jansen, Reinier J.; van Egmond, René; de Ridder, Huib

    2016-01-01

    The role of task prioritization in performance tradeoffs during multi-tasking has received widespread attention. However, little is known on whether people have preferences regarding tasks, and if so, whether these preferences conflict with priority instructions. Three experiments were conducted with a high-speed driving game and an auditory memory task. In Experiment 1, participants did not receive priority instructions. Participants performed different sequences of single-task and dual-task conditions. Task performance was evaluated according to participants’ retrospective accounts on preferences. These preferences were reformulated as priority instructions in Experiments 2 and 3. The results showed that people differ in their preferences regarding task prioritization in an experimental setting, which can be overruled by priority instructions, but only after increased dual-task exposure. Additional measures of mental effort showed that performance tradeoffs had an impact on mental effort. The interpretation of these findings was used to explore an extension of Threaded Cognition Theory with Hockey’s Compensatory Control Model. PMID:27391779

  18. Towards Proactive Policies supporting Event-based Task Delegation

    OpenAIRE

    Gaaloul, Khaled; Miseldine, Philip; Charoy, François

    2009-01-01

    International audience Delegation mechanisms are receiving increasing interest from the research community. Task delegation is a mechanism that supports organisational flexibility in the human-centric workflow systems, and ensures delegation of authority in access control systems. In this paper, we consider task delegation as an advanced security mechanism supporting policy decision. We define an approach to support dynamic delegation of authority within an access control framework. The no...

  19. TRACE Project. Deliverable 3.4. Driving Task-Related Factors

    OpenAIRE

    Naing, C.; Hill, J.; Maguire, M.; Schick, S.; Eggers, A.; Pastor, C. (Carlos); Van Elslande, P.; Fouquet, K.; Banos, A.; PLAZA, J; Tomasch, E.; Hell, W.

    2008-01-01

    Rapport de recherche Driving task-related factors by definition are 'directly and causally contributing to the accident occurrence, very specific and detailed, are short-term lasting or dynamic in nature, and refer to the actual conditions of the components'. The aim was to analyse specific driving task-related factors to investigate how these type of factors affect the driver undertaking their tasks within driving. A selection of driving task-related factors were chosen and analysed using...

  20. Visualization design and verification of Ada tasking using timing diagrams

    Science.gov (United States)

    Vidale, R. F.; Szulewski, P. A.; Weiss, J. B.

    1986-01-01

    The use of timing diagrams is recommended in the design and testing of multi-task Ada programs. By displaying the task states vs. time, timing diagrams can portray the simultaneous threads of data flow and control which characterize tasking programs. This description of the system's dynamic behavior from conception to testing is a necessary adjunct to other graphical techniques, such as structure charts, which essentially give a static view of the system. A series of steps is recommended which incorporates timing diagrams into the design process. Finally, a description is provided of a prototype Ada Execution Analyzer (AEA) which automates the production of timing diagrams from VAX/Ada debugger output.

  1. Analysis of Brain Cognitive State for Arithmetic Task and Motor Task Using Electroencephalography Signal

    Directory of Open Access Journals (Sweden)

    R Kalpana

    2013-08-01

    Full Text Available To localize the brain dynamics for cognitive processes from EEG signature has been a challenging taskfrom last two decades. In this paper we explore the spatial-temporal correlations of brain electricalneuronal activity for cognitive task such as Arithmetic and Motor Task using 3D cortical distributionmethod. Ten healthy right handed volunteers participated in the experiment. EEG signal was acquiredduring resting state with eyes open and eyes closed; performing motor task and arithmetic calculations.The signal was then computed for three dimensional cortical distributions on realistic head model withMNI152 template using standardized low resolution brain electromagnetic tomography (sLORETA. Thiswas followed by an appropriate standardization of the current density, producing images of electricneuronal activity without localization bias. Neuronal generators responsible for cognitive state such asArithmetic Task and Motor Task were localized. The result was correlated with the previous neuroimaging(fMRI study investigation. Hence our result directed that the neuronal activity from EEG signal can bedemonstrated in cortical level with good spatial resolution. 3D cortical distribution method, thus, may beused to obtain both spatial and temporal information from EEG signal and may prove to be a significanttechnique to investigate the cognitive functions in mental health and brain dysfunctions. Also, it may behelpful for brain/human computer interfacing.

  2. Concert halls with strong lateral reflections enhance musical dynamics.

    Science.gov (United States)

    Pätynen, Jukka; Tervo, Sakari; Robinson, Philip W; Lokki, Tapio

    2014-03-25

    One of the most thrilling cultural experiences is to hear live symphony-orchestra music build up from a whispering passage to a monumental fortissimo. The impact of such a crescendo has been thought to depend only on the musicians' skill, but here we show that interactions between the concert-hall acoustics and listeners' hearing also play a major role in musical dynamics. These interactions contribute to the shoebox-type concert hall's established success, but little prior research has been devoted to dynamic expression in this three-part transmission chain as a complete system. More forceful orchestral playing disproportionately excites high frequency harmonics more than those near the note's fundamental. This effect results in not only more sound energy, but also a different tone color. The concert hall transmits this sound, and the room geometry defines from which directions acoustic reflections arrive at the listener. Binaural directional hearing emphasizes high frequencies more when sound arrives from the sides of the head rather than from the median plane. Simultaneously, these same frequencies are emphasized by higher orchestral-playing dynamics. When the room geometry provides reflections from these directions, the perceived dynamic range is enhanced. Current room-acoustic evaluation methods assume linear behavior and thus neglect this effect. The hypothesis presented here is that the auditory excitation by reflections is emphasized with an orchestra forte most in concert halls with strong lateral reflections. The enhanced dynamic range provides an explanation for the success of rectangularly shaped concert-hall geometry.

  3. Correlates of academic procrastination: discomfort, task aversiveness, and task capability.

    Science.gov (United States)

    Milgram, N; Marshevsky, S; Sadeh, C

    1995-03-01

    The relationships among five aspects of academic procrastination--behavioral delay, personal upset about the delay, task aversiveness, task capability, and the desire to reduce behavioral delay--were investigated in 10th-grade Israeli students (N = 195). Upset about delay was weakly related to delay itself, and--unlike delay--was strongly related to perceived capability to perform academic tasks and to the desire to change delaying behavior. Students delayed more on academic tasks labeled unpleasant than pleasant, were neutral in between, and were correspondingly more upset about the former than the latter. They more frequently acknowledged reasons for academic procrastination that were less threatening to their self-image (e.g., problems in time management) than reasons that were more threatening (e.g., lack of ability). Interest in reducing delay is related more to self-perceived ability to handle tasks than to time spent procrastinating or reasons given for procrastinating. PMID:7760291

  4. 设计有活力的学习任务--谈职校学生学习兴趣的激发%Design a Dynamic Learning Tasks---Talk about Vocational Schools Stimulate Students Interest in Learning

    Institute of Scientific and Technical Information of China (English)

    徐兴振

    2014-01-01

    The task is to learn by an objective prerequisite and three objective elements integration, it is the precondition of teaching design, is also the process of building hardware platform and extract the valuable knowledge and skills, based on respect for students' learning behavior, meet the demand of students information, so as to stimulate students’ interest in learning.%学习任务是由一个客观前提以及三个客观要素整合而成,它是教学设计的前提,同时也是搭建硬件平台的过程并提炼出有价值的知识点与技能点,以此为基础尊重学生的学习行为,满足学生的资讯需求,从而激发学生的学习兴趣。

  5. Task Models in the Digital Ocean

    Science.gov (United States)

    DiCerbo, Kristen E.

    2014-01-01

    The Task Model is a description of each task in a workflow. It defines attributes associated with that task. The creation of task models becomes increasingly important as the assessment tasks become more complex. Explicitly delineating the impact of task variables on the ability to collect evidence and make inferences demands thoughtfulness from…

  6. Cosmetology Series. Duty Task List.

    Science.gov (United States)

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This document contains the occupational duty/task lists for three occupations in the cosmetology series. Each occupation is divided into a number of duties. A separate page for each duty in the occupation lists the tasks in that duty along with its code number and columns to indicate whether that particular duty has been taught and to provide…

  7. Task modeling for collaborative authoring

    NARCIS (Netherlands)

    Veer, van der Gerrit; Kulyk, Olga; Vyas, Dhaval; Kubbe, Onno; Ebert, Achim; Dittmar, A.; Forbrig, P.

    2011-01-01

    Motivation –Task analysis for designing modern collaborative work needs a more fine grained approach. Especially in a complex task domain, like collaborative scientific authoring, when there is a single overall goal that can only be accomplished only by collaboration between multiple roles, each req

  8. Decision paths in complex tasks

    Science.gov (United States)

    Galanter, Eugene

    1991-01-01

    Complex real world action and its prediction and control has escaped analysis by the classical methods of psychological research. The reason is that psychologists have no procedures to parse complex tasks into their constituents. Where such a division can be made, based say on expert judgment, there is no natural scale to measure the positive or negative values of the components. Even if we could assign numbers to task parts, we lack rules i.e., a theory, to combine them into a total task representation. We compare here two plausible theories for the amalgamation of the value of task components. Both of these theories require a numerical representation of motivation, for motivation is the primary variable that guides choice and action in well-learned tasks. We address this problem of motivational quantification and performance prediction by developing psychophysical scales of the desireability or aversiveness of task components based on utility scaling methods (Galanter 1990). We modify methods used originally to scale sensory magnitudes (Stevens and Galanter 1957), and that have been applied recently to the measure of task 'workload' by Gopher and Braune (1984). Our modification uses utility comparison scaling techniques which avoid the unnecessary assumptions made by Gopher and Braune. Formula for the utility of complex tasks based on the theoretical models are used to predict decision and choice of alternate paths to the same goal.

  9. A Synthetic Heuristic Algorithm for Independent Task Scheduling in Cloud Systems

    Directory of Open Access Journals (Sweden)

    Arash Ghorbannia Delavar

    2011-11-01

    Full Text Available In this paper, we present a synthetic method based on genetic algorithm, for independent task scheduling in cloud computing systems. Task scheduling is a major issue in large-scale distributed systems that impresses on system performance. For some reasons such as heterogeneous and dynamic features in cloud environment, task scheduling has appeared as a NP-complete problem. Our proposed algorithm (SHIS, by some goal oriented operations such as, making an optimize initial population, dual step evaluation, and also, running the tasks by a special ordering considering resource load balancing and quality of service, achieves the optimize makespan. It also decreases the probability of task failure rate on running, based on the resource failure frequency rate, and also decreases the task starvation problem. It supports the scheduling for new entered tasks in system by a dynamic method. The experimental results show that the proposed method solution is better than the other studied algorithms.

  10. The Adaptation of Dynamic Test Using the Inventory of Piaget's Developmental Task (IPDT): An Initial Validation and Application%“儿童认知发展水平诊断工具”动态测验的初步编制与应用

    Institute of Scientific and Technical Information of China (English)

    张丽锦; 陈亮; 方富熹

    2011-01-01

    To understand children's cognitive development, there is an increasing need for developing and validating assessment and diagnostic methods in both research and education practices. The conventional static tests focus on a particular state of ability development, rather than children's potential ability. Building on Vygotsky's concept of "Zone of Proximal Development (ZPD)", dynamic testing has the potential to detect latent capacity of development, thus providing a way to more comprehensively assess children's cognitive capacity. Most of dynamic tests were usually adaptations of classical intelligence test tasks, exploring children's latent capacity by dynamic assessment method. So, the purpose of the current study was to develop and standardize a new dynamic test based on conservation and relation domain assessment adapted from the Inventory of Piaget's Developmental Tasks (IPDT), and to examine the validity of this new dynamic test with a sample of children with relatively low academic achievement.To validate the new dynamic test, fifty-four eight or nine years old children were randomly selected from the third grade in two public elementary schools. The dynamic testing involved four stages: pretest, intervention, modifiable, and posttest; each with a different set of testing questions. In accordance with their test performance, the participants also received six different levels of clues, developed based on theories of cognitive development as well as prior dynamic tests in other domains. The results showed that with the incremental steps of intervention in response children's performance, their performance gradually improved, providing some initial evidence for the validity of this new test.The validated dynamic test was first administered to two groups of eight and nine years old children: theexperimental group (n = 35) children with relatively lower academic achievement, and the control group (n = 33) with relatively moderate levels of academic achievement

  11. Corticospinal Excitability of Trunk Muscles during Different Postural Tasks.

    Science.gov (United States)

    Chiou, Shin-Yi; Gottardi, Sam E A; Hodges, Paul W; Strutton, Paul H

    2016-01-01

    Evidence suggests that the primary motor cortex (M1) is involved in both voluntary, goal-directed movements and in postural control. Trunk muscles are involved in both tasks, however, the extent to which M1 controls these muscles in trunk flexion/extension (voluntary movement) and in rapid shoulder flexion (postural control) remains unclear. The purpose of this study was to investigate this question by examining excitability of corticospinal inputs to trunk muscles during voluntary and postural tasks. Twenty healthy adults participated. Transcranial magnetic stimulation was delivered to the M1 to examine motor evoked potentials (MEPs) in the trunk muscles (erector spinae (ES) and rectus abdominis (RA)) during dynamic shoulder flexion (DSF), static shoulder flexion (SSF), and static trunk extension (STE). The level of background muscle activity in the ES muscles was matched across tasks. MEP amplitudes in ES were significantly larger in DSF than in SSF or in STE; however, this was not observed for RA. Further, there were no differences in levels of muscle activity in RA between tasks. Our findings reveal that corticospinal excitability of the ES muscles appears greater during dynamic anticipatory posture-related adjustments than during static tasks requiring postural (SSF) and goal-directed voluntary (STE) activity. These results suggest that task-oriented rehabilitation of trunk muscles should be considered for optimal transfer of therapeutic effect to function.

  12. Reward-based learning of a redundant task.

    Science.gov (United States)

    Tamagnone, Irene; Casadio, Maura; Sanguineti, Vittorio

    2013-06-01

    Motor skill learning has different components. When we acquire a new motor skill we have both to learn a reliable action-value map to select a highly rewarded action (task model) and to develop an internal representation of the novel dynamics of the task environment, in order to execute properly the action previously selected (internal model). Here we focus on a 'pure' motor skill learning task, in which adaptation to a novel dynamical environment is negligible and the problem is reduced to the acquisition of an action-value map, only based on knowledge of results. Subjects performed point-to-point movement, in which start and target positions were fixed and visible, but the score provided at the end of the movement depended on the distance of the trajectory from a hidden viapoint. Subjects did not have clues on the correct movement other than the score value. The task is highly redundant, as infinite trajectories are compatible with the maximum score. Our aim was to capture the strategies subjects use in the exploration of the task space and in the exploitation of the task redundancy during learning. The main findings were that (i) subjects did not converge to a unique solution; rather, their final trajectories are determined by subject-specific history of exploration. (ii) with learning, subjects reduced the trajectory's overall variability, but the point of minimum variability gradually shifted toward the portion of the trajectory closer to the hidden via-point. PMID:24187205

  13. Asynchronous Task-Based Polar Decomposition on Manycore Architectures

    KAUST Repository

    Sukkari, Dalal

    2016-10-25

    This paper introduces the first asynchronous, task-based implementation of the polar decomposition on manycore architectures. Based on a new formulation of the iterative QR dynamically-weighted Halley algorithm (QDWH) for the calculation of the polar decomposition, the proposed implementation replaces the original and hostile LU factorization for the condition number estimator by the more adequate QR factorization to enable software portability across various architectures. Relying on fine-grained computations, the novel task-based implementation is also capable of taking advantage of the identity structure of the matrix involved during the QDWH iterations, which decreases the overall algorithmic complexity. Furthermore, the artifactual synchronization points have been severely weakened compared to previous implementations, unveiling look-ahead opportunities for better hardware occupancy. The overall QDWH-based polar decomposition can then be represented as a directed acyclic graph (DAG), where nodes represent computational tasks and edges define the inter-task data dependencies. The StarPU dynamic runtime system is employed to traverse the DAG, to track the various data dependencies and to asynchronously schedule the computational tasks on the underlying hardware resources, resulting in an out-of-order task scheduling. Benchmarking experiments show significant improvements against existing state-of-the-art high performance implementations (i.e., Intel MKL and Elemental) for the polar decomposition on latest shared-memory vendors\\' systems (i.e., Intel Haswell/Broadwell/Knights Landing, NVIDIA K80/P100 GPUs and IBM Power8), while maintaining high numerical accuracy.

  14. Thalamocortical rhythms during a vibrotactile detection task.

    Science.gov (United States)

    Haegens, Saskia; Vázquez, Yuriria; Zainos, Antonio; Alvarez, Manuel; Jensen, Ole; Romo, Ranulfo

    2014-04-29

    To explore the role of oscillatory dynamics of the somatosensory thalamocortical network in perception and decision making, we recorded the simultaneous neuronal activity in the ventral posterolateral nucleus (VPL) of the somatosensory thalamus and primary somatosensory cortex (S1) in two macaque monkeys performing a vibrotactile detection task. Actively detecting a vibrotactile stimulus and reporting its perception elicited a sustained poststimulus beta power increase in VPL and an alpha power decrease in S1, in both stimulus-present and stimulus-absent trials. These oscillatory dynamics in the somatosensory thalamocortical network depended on the behavioral context: they were stronger for the active detection condition than for a passive stimulation condition. Furthermore, contrasting stimulus-present vs. stimulus-absent responses, we found that poststimulus theta power increased in both VPL and S1, and alpha/beta power decreased in S1, reflecting the monkey's perceptual decision but not the motor response per se. Additionally, higher prestimulus alpha power in S1 correlated with an increased probability of the monkey reporting a stimulus, regardless of the actual presence of a stimulus. Thus, we found task-related modulations in oscillatory activity, not only in the neocortex but also in the thalamus, depending on behavioral context. Furthermore, oscillatory modulations reflected the perceptual decision process and subsequent behavioral response. We conclude that these early sensory regions, in addition to their primary sensory functions, may be actively involved in perceptual decision making.

  15. Multiple paths in complex tasks

    Science.gov (United States)

    Galanter, Eugene; Wiegand, Thomas; Mark, Gloria

    1987-01-01

    The relationship between utility judgments of subtask paths and the utility of the task as a whole was examined. The convergent validation procedure is based on the assumption that measurements of the same quantity done with different methods should covary. The utility measures of the subtasks were obtained during the performance of an aircraft flight controller navigation task. Analyses helped decide among various models of subtask utility combination, whether the utility ratings of subtask paths predict the whole tasks utility rating, and indirectly, whether judgmental models need to include the equivalent of cognitive noise.

  16. Task-space sensory feedback control of robot manipulators

    CERN Document Server

    Cheah, Chien Chern

    2015-01-01

    This book presents recent advances in robot control theory on task space sensory feedback control of robot manipulators. By using sensory feedback information, the robot control systems are robust to various uncertainties in modelling and calibration errors of the sensors. Several sensory task space control methods that do not require exact knowledge of either kinematics or dynamics of robots, are presented. Some useful methods such as approximate Jacobian control, adaptive Jacobian control, region control and multiple task space regional feedback are included. These formulations and methods give robots a high degree of flexibility in dealing with unforeseen changes and uncertainties in its kinematics and dynamics, which is similar to human reaching movements and tool manipulation. It also leads to the solution of several long-standing problems and open issues in robot control, such as force control with constraint uncertainty, control of multi-fingered robot hand with uncertain contact points, singularity i...

  17. Microgravity Science and Applications Program tasks, 1987 revision

    Science.gov (United States)

    1988-01-01

    A compilation is presented of the active research tasks as of the end of the FY87 of the Microgravity Science and Applications Program, NASA-Office of Space Science and Applications, involving several NASA centers and other organizations. An overview is provided of the program scope for managers and scientists in industry, university, and government communities. An introductory description is provided of the program along with the strategy and overall goal, identification of the organizational structures and people involved, and a description of each task. A list of recent publications is also provided. The tasks are grouped into six major categories: Electronic Materials; Solidification of Metals, Alloys, and Composites; Fluid Dynamics and Transport Phenomena; Biotechnology; Glasses and Ceramics; and Combustion. Other categories include Experimental Technology, General Studies and Surveys; Foreign Government Affiliations; Industrial Affiliations; and Physics and Chemistry Experiments (PACE). The tasks are divided into ground based and flight experiments.

  18. Microgravity Science and Applications Program tasks, 1990 revision

    Science.gov (United States)

    1991-01-01

    The active research tasks as of the end of the fiscal year 1990 sponsored by the Microgravity Science and Applications Division of the NASA Office of Space Science and Applications are compiled. The purpose is to provide an overview of the program scope for managers and scientists in industry, university, and government communities. The report includes an introductory description of the program, the strategy and overall goal; an index of principle investigators; and a description of each task. A list of recent publications is also provided. The tasks are grouped into six major categories: electronic materials; solidification of metals, alloys, and composites; fluid dynamics and transport phenomena; biotechnology; glasses and ceramics; combustion; experimental technology; facilities; and Physics And Chemistry Experiments (PACE). The tasks are divided into ground-based and flight experiments.

  19. Microgravity Science and Applications Program tasks, 1988 revision

    Science.gov (United States)

    1989-01-01

    The active research tasks as of the end of the fiscal year 1988 of the Microgravity Science and Applications Program, NASA-Office of Space Science and Applications, involving several NASA centers and other organizations are compiled. The purpose is to provide an overview of the program scope for managers and scientists in industry, university, and government communities. Also included are an introductory description of the program, the strategy and overall goal, identification of the organizational structures and people involved, and a description of each task. A list of recent publications is provided. The tasks are grouped into six major categories: electronic materials; solidification of metals, alloys, and composites; fluid dynamics and transport phenomena; biotechnology; glasses and ceramics; and combustion. Other categories include experimental technology, general studies and surveys; foreign government affiliations; industrial affiliations; and Physics And Chemistry Experiments (PACE). The tasks are divided into ground-based and flight experiments.

  20. Task Delegation Based Access Control Models for Workflow Systems

    Science.gov (United States)

    Gaaloul, Khaled; Charoy, François

    e-Government organisations are facilitated and conducted using workflow management systems. Role-based access control (RBAC) is recognised as an efficient access control model for large organisations. The application of RBAC in workflow systems cannot, however, grant permissions to users dynamically while business processes are being executed. We currently observe a move away from predefined strict workflow modelling towards approaches supporting flexibility on the organisational level. One specific approach is that of task delegation. Task delegation is a mechanism that supports organisational flexibility, and ensures delegation of authority in access control systems. In this paper, we propose a Task-oriented Access Control (TAC) model based on RBAC to address these requirements. We aim to reason about task from organisational perspectives and resources perspectives to analyse and specify authorisation constraints. Moreover, we present a fine grained access control protocol to support delegation based on the TAC model.

  1. On the validation of SPDM task verification facility

    NARCIS (Netherlands)

    Ma, Ou; Wang, Jiegao; Misra, Sarthak; Liu, Michael

    2004-01-01

    This paper describes a methodology for validating a ground-based, hardware-in-the-loop, space-robot simulation facility. This facility, called ‘‘SPDM task verification facility,’’ is being developed by the Canadian Space Agency for the purpose of verifying the contact dynamics performance of the spe

  2. Task Space Tracking for Manipulators

    Directory of Open Access Journals (Sweden)

    Olav Egeland

    1985-04-01

    Full Text Available For the purpose of controlling a manipulator in the task space, a linear model with task space position and velocity as state variables can be developed. This is done by means of exact compensation of the state-space model non-linearities using non-linear feedback. In this paper, feedback control for this linear state space model is developed using optimal control theory. Integral action is included to compensate for unmodeled forces and torques. In the resulting control system, the problem of transforming the task space trajectory to the joint space is avoided, and the controller parameters can be chosen to satisfy requirements specified in the task space. Simulation experiments show promising results.

  3. Adaptive Algorithm For Identification Of The Environment Parameters In Contact Tasks

    International Nuclear Information System (INIS)

    An adaptive algorithm for identification of the unknown parameters of the dynamic environment in contact tasks is proposed in this paper using the augmented least square estimation method. An approximate environment digital simulator for the continuous environment dynamics is derived, i.e. a discrete transfer function which has the approximately the same characteristics as the continuous environment dynamics is found. For solving this task a method named hold equivalence is used. The general model of the environment dynamics is given and the case when the environment dynamics is represented by second order models with parameter uncertainties is considered. (Author)

  4. Transfer of training from one working memory task to another: behavioural and neural evidence

    OpenAIRE

    Beatty, Erin L.; Oshin Vartanian

    2015-01-01

    N-back working memory (WM) tasks necessitate the maintenance and updating of dynamic rehearsal sets during performance. The delayed matching-to-sample (dMTS) task is another WM task, which in turn involves the encoding, maintenance, and retrieval of stimulus representations in sequential order. Because both n-back and dMTS engage WM function, we hypothesized that compared to a control task not taxing WM, training on the n-back task would be associated with better performance on dMTS by virtue...

  5. SENSEVAL-2 Japanese Translation Task

    OpenAIRE

    Kurohashi, Sadao; Uchimoto, Kiyotaka

    2003-01-01

    This paper describes the Senseval-2 Japanese translation task. In this task, word senses are defined according to distinct translations in a given target language. A translation memory (TM) was constructed which contains, for each Japanese head word, a list of typical Japanese expressions and their English translations. For each test word instance, participants were required to submit the TM record best approximating that usage, or alternatively, actual target word translations. There were 9 ...

  6. Annual Progress report - General Task

    Energy Technology Data Exchange (ETDEWEB)

    Wesnousky, S.G.

    1993-09-30

    This report provides a summary of progress for the project {open_quotes}Evaluation of the Geologic Relations and Seismotectonic Stability of the Yucca Mountain Area, Nevada Nuclear Waste Site Investigation (NNWSI).{close_quotes} A similar report was previously provided for the period of 1 October 1991 to 30 September 1992. The report initially covers the activities of the General Task and is followed by sections that describe the progress of the other ongoing tasks.

  7. Age-related Multiscale Changes in Brain Signal Variability in Pre-task versus Post-task Resting-state EEG.

    Science.gov (United States)

    Wang, Hongye; McIntosh, Anthony R; Kovacevic, Natasa; Karachalios, Maria; Protzner, Andrea B

    2016-07-01

    Recent empirical work suggests that, during healthy aging, the variability of network dynamics changes during task performance. Such variability appears to reflect the spontaneous formation and dissolution of different functional networks. We sought to extend these observations into resting-state dynamics. We recorded EEG in young, middle-aged, and older adults during a "rest-task-rest" design and investigated if aging modifies the interaction between resting-state activity and external stimulus-induced activity. Using multiscale entropy as our measure of variability, we found that, with increasing age, resting-state dynamics shifts from distributed to more local neural processing, especially at posterior sources. In the young group, resting-state dynamics also changed from pre- to post-task, where fine-scale entropy increased in task-positive regions and coarse-scale entropy increased in the posterior cingulate, a key region associated with the default mode network. Lastly, pre- and post-task resting-state dynamics were linked to performance on the intervening task for all age groups, but this relationship became weaker with increasing age. Our results suggest that age-related changes in resting-state dynamics occur across different spatial and temporal scales and have consequences for information processing capacity. PMID:26942319

  8. Capability-based task allocation in emergency-response environments: a coalition-formation approach

    OpenAIRE

    FATEMI, Afsaneh; Zamanifar, Kamran; NEMATBAKHSH, Naser

    2013-01-01

    This paper addresses coalition formation, based on agent capabilities, centered on task allocation in emergency-response environments (EREs). EREs are environments that need fast task completion as their main requirement. We propose a team-based organization model, based on an existing organization model for adaptive complex systems. The model has some key characteristics that are beneficial for EREs: agents act in dynamic, open domains; agents collaborate in completing group tasks;...

  9. Improving load balance with flexibly assignable tasks

    Energy Technology Data Exchange (ETDEWEB)

    Pinar, Ali; Hendrickson, Bruce

    2003-09-09

    In many applications of parallel computing, distribution ofthe data unambiguously implies distribution of work among processors. Butthere are exceptions where some tasks can be assigned to one of severalprocessors without altering the total volume of communication. In thispaper, we study the problem of exploiting this flexibility in assignmentof tasks to improve load balance. We first model the problem in terms ofnetwork flow and use combinatorial techniques for its solution. Ourparametric search algorithms use maximum flow algorithms for probing on acandidate optimal solution value. We describe two algorithms to solve theassignment problem with \\logW_T and vbar P vbar probe calls, w here W_Tand vbar P vbar, respectively, denote the total workload and number ofproce ssors. We also define augmenting paths and cuts for this problem,and show that anyalgorithm based on augmenting paths can be used to findan optimal solution for the task assignment problem. We then consideracontinuous version of the problem, and formulate it as a linearlyconstrained optimization problem, i.e., \\min\\|Ax\\|_\\infty,\\; {\\rms.t.}\\;Bx=d. To avoid solving an intractable \\infty-norm optimization problem,we show that in this case minimizing the 2-norm is sufficient to minimizethe \\infty-norm, which reduces the problem to the well-studiedlinearly-constrained least squares problem. The continuous version of theproblem has the advantage of being easily amenable to parallelization.Our experiments with molecular dynamics and overlapped domaindecomposition applications proved the effectiveness of our methods withsignificant improvements in load balance. We also discuss how ourtechniques can be enhanced for heterogeneous systems.

  10. Number & operations task & drill sheets

    CERN Document Server

    Reed, Nat

    2011-01-01

    For grades 6-8, our State Standards-based combined resource meets the number & operations concepts addressed by the NCTM standards and encourages the students to review the concepts in unique ways. The task sheets introduce the mathematical concepts to the students around a central problem taken from real-life experiences, while the drill sheets provide warm-up and timed practice questions for the students to strengthen their procedural proficiency skills. Included are problems involving place value, fractions, addition, subtraction and using money. The combined task & drill sheets offer spac

  11. ELIRF at MEDIAEVAL 2013: Spoken Web Search Task

    OpenAIRE

    Gómez Adrian, Jon Ander; Hurtado Oliver, Lluis Felip; Calvo Lance, Marcos; Sanchís Arnal, Emilio

    2013-01-01

    In this paper, we present the systems that the Natural Lan- guage Engineering and Pattern Recognition group (ELiRF) has submitted to the MediaEval 2013 Spoken Web Search task. All of them are based on a Subsequence Dynamic Time Warping algorithm and are zero-resources systems. Spanish Government [TIN2011-28169-C05] FPU [ AP2010-4193] Gómez Adrian, JA.; Hurtado Oliver, LF.; Calvo Lance, M.; Sanchís Arnal, E. (2013). ELIRF at MEDIAEVAL 2013: Spoken Web Search Task. Multimed...

  12. Task management in the new ATLAS production system

    International Nuclear Information System (INIS)

    This document describes the design of the new Production System of the ATLAS experiment at the LHC [1]. The Production System is the top level workflow manager which translates physicists' needs for production level processing and analysis into actual workflows executed across over a hundred Grid sites used globally by ATLAS. As the production workload increased in volume and complexity in recent years (the ATLAS production tasks count is above one million, with each task containing hundreds or thousands of jobs) there is a need to upgrade the Production System to meet the challenging requirements of the next LHC run while minimizing the operating costs. In the new design, the main subsystems are the Database Engine for Tasks (DEFT) and the Job Execution and Definition Interface (JEDI). Based on users' requests, DEFT manages inter-dependent groups of tasks (Meta-Tasks) and generates corresponding data processing workflows. The JEDI component then dynamically translates the task definitions from DEFT into actual workload jobs executed in the PanDA Workload Management System [2]. We present the requirements, design parameters, basics of the object model and concrete solutions utilized in building the new Production System and its components.

  13. SitLog: A Programming Language for Service Robot Tasks

    Directory of Open Access Journals (Sweden)

    Luis A. Pineda

    2013-10-01

    Full Text Available In this paper we present SitLog: a declarative situation-oriented logical language for programming situated service robot tasks. The formalism is task and domain independent, and can be used in a wide variety of settings. SitLog can also be seen as a behaviour engineering specification and interpretation formalism to support action selection by autonomous agents during the execution of complex tasks. The language combines the recursive transition network formalism, extended with functions to express dynamic and contextualized task structures, with a functional language to express control and content information. The SitLog interpreter is written in Prolog and SitLog’s programs follow closely the Prolog notation, permitting the declarative specification and direct interpretation of complex applications in a modular and compact form. We discuss the structure and representation of service robot tasks in practical settings and how these can be expressed in SitLog. The present framework has been tested in the service robot Golem-II+ using the specification and programming of the typical tasks which require completion in the RoboCup@Home Competition.

  14. Force-field compensation in a manual tracking task.

    Directory of Open Access Journals (Sweden)

    Valentina Squeri

    Full Text Available This study addresses force/movement control in a dynamic "hybrid" task: the master sub-task is continuous manual tracking of a target moving along an eight-shaped Lissajous figure, with the tracking error as the primary performance index; the slave sub-task is compensation of a disturbing curl viscous field, compatibly with the primary performance index. The two sub-tasks are correlated because the lateral force the subject must exert on the eight-shape must be proportional to the longitudinal movement speed in order to perform a good tracking. The results confirm that visuo-manual tracking is characterized by an intermittent control mechanism, in agreement with previous work; the novel finding is that the overall control patterns are not altered by the presence of a large deviating force field, if compared with the undisturbed condition. It is also found that the control of interaction-forces is achieved by a combination of arm stiffness properties and direct force control, as suggested by the systematic lateral deviation of the trajectories from the nominal path and the comparison between perturbed trials and catch trials. The coordination of the two sub-tasks is quickly learnt after the activation of the deviating force field and is achieved by a combination of force and the stiffness components (about 80% vs. 20%, which is a function of the implicit accuracy of the tracking task.

  15. Use cases versus task descriptions

    DEFF Research Database (Denmark)

    Lauesen, Søren; Kuhail, Mohammad Amin

    2011-01-01

    without specifying a dialog. [Contribution] It turned out that the traditional use cases covered the customer's needs poorly in areas where improvement was important but diffi-cult. Use cases also restricted the solution space severely. Tasks didn't have these problems and allowed an easy comparison...

  16. A Population of Assessment Tasks

    Science.gov (United States)

    Daro, Phil; Burkhardt, Hugh

    2012-01-01

    We propose the development of a "population" of high-quality assessment tasks that cover the performance goals set out in the "Common Core State Standards for Mathematics." The population will be published. Tests are drawn from this population as a structured random sample guided by a "balancing algorithm."

  17. Novice supervisors' tasks and training

    DEFF Research Database (Denmark)

    Nielsen, Jan; Jacobsen, Claus Haugaard; Mathiesen, Birgit Bork

    2012-01-01

    were confronted with complicated jobs, e.g., group, internal and interdisciplinary supervision, but were not prepared, i.e. trained, prior to these tasks. These findings imply that more training is needed for novice supervisors. Preferably, this training should be introduced before, or at least...

  18. Interpretation Tasks for Grammar Teaching.

    Science.gov (United States)

    Ellis, Rod

    1995-01-01

    The traditional approach to grammar teaching provides learners with opportunities to produce specific grammatical structures. This article explores an alternative approach, one based on interpreting input. The rationale for the approach is discussed, as are the principles for designing interpretation tasks for grammar teaching. (Contains 35…

  19. Computer-Related Task Performance

    DEFF Research Database (Denmark)

    Longstreet, Phil; Xiao, Xiao; Sarker, Saonee

    2016-01-01

    The existing information system (IS) literature has acknowledged computer self-efficacy (CSE) as an important factor contributing to enhancements in computer-related task performance. However, the empirical results of CSE on performance have not always been consistent, and increasing an individua...

  20. Task-driven dictionary learning.

    Science.gov (United States)

    Mairal, Julien; Bach, Francis; Ponce, Jean

    2012-04-01

    Modeling data with linear combinations of a few elements from a learned dictionary has been the focus of much recent research in machine learning, neuroscience, and signal processing. For signals such as natural images that admit such sparse representations, it is now well established that these models are well suited to restoration tasks. In this context, learning the dictionary amounts to solving a large-scale matrix factorization problem, which can be done efficiently with classical optimization tools. The same approach has also been used for learning features from data for other purposes, e.g., image classification, but tuning the dictionary in a supervised way for these tasks has proven to be more difficult. In this paper, we present a general formulation for supervised dictionary learning adapted to a wide variety of tasks, and present an efficient algorithm for solving the corresponding optimization problem. Experiments on handwritten digit classification, digital art identification, nonlinear inverse image problems, and compressed sensing demonstrate that our approach is effective in large-scale settings, and is well suited to supervised and semi-supervised classification, as well as regression tasks for data that admit sparse representations. PMID:21808090

  1. A framework for cognitive task analysis in systems design

    International Nuclear Information System (INIS)

    The present rapid development if advanced information technology and its use for support of operators of complex technical systems are changing the content of task analysis towards the analysis of mental activities in decision making. Automation removes the humans from routine tasks, and operators are left with disturbance control and critical diagnostic tasks, for which computers are suitable for support, if it is possible to match the computer strategies and interface formats dynamically to the requirements of the current task by means of an analysis of the cognitive task. Such a cognitive task analysis will not aim at a description of the information processes suited for particular control situations. It will rather aim at an analysis in order to identify the requirements to be considered along various dimensions of the decision tasks, in order to give the user - i.e. a decision maker - the freedom to adapt his performance to system requirements in a way which matches his process resources and subjective preferences. To serve this purpose, a number of analyses at various levels are needed to relate the control requirements of the system to the information processes and to the processing resources offered by computers and humans. The paper discusses the cognitive task analysis in terms of the following domains: The problem domain, which is a representation of the functional properties of the system giving a consistent framework for identification of the control requirements of the system; the decision sequences required for typical situations; the mental strategies and heuristics which are effective and acceptable for the different decision functions; and the cognitive control mechanisms used, depending upon the level of skill which can/will be applied. Finally, the end-users' criteria for choice of mental strategies in the actual situation are considered, and the need for development of criteria for judging the ultimate user acceptance of computer support is

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

    Science.gov (United States)

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

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

  3. Tasks for Easily Modifiable Virtual Environments

    Science.gov (United States)

    Swier, Robert

    2014-01-01

    Recent studies of learner interaction in virtual worlds have tended to select basic tasks involving open-ended communication. There is evidence that such tasks are supportive of language acquisition, however it may also be beneficial to consider more complex tasks. Research in task-based learning has identified features such as non-linguistic…

  4. Working-Memory Load and Temporal Myopia in Dynamic Decision Making

    Science.gov (United States)

    Worthy, Darrell A.; Otto, A. Ross; Maddox, W. Todd

    2012-01-01

    We examined the role of working memory (WM) in dynamic decision making by having participants perform decision-making tasks under single-task or dual-task conditions. In 2 experiments participants performed dynamic decision-making tasks in which they chose 1 of 2 options on each trial. The decreasing option always gave a larger immediate reward…

  5. SWIFT: task-based hydrodynamics and gravity for cosmological simulations

    CERN Document Server

    Theuns, Tom; Schaller, Matthieu; Gonnet, Pedro

    2015-01-01

    Simulations of galaxy formation follow the gravitational and hydrodynamical interactions between gas, stars and dark matter through cosmic time. The huge dynamic range of such calculations severely limits strong scaling behaviour of the community codes in use, with load-imbalance, cache inefficiencies and poor vectorisation limiting performance. The new swift code exploits task-based parallelism designed for many-core compute nodes interacting via MPI using asynchronous communication to improve speed and scaling. A graph-based domain decomposition schedules interdependent tasks over available resources. Strong scaling tests on realistic particle distributions yield excellent parallel efficiency, and efficient cache usage provides a large speed-up compared to current codes even on a single core. SWIFT is designed to be easy to use by shielding the astronomer from computational details such as the construction of the tasks or MPI communication. The techniques and algorithms used in SWIFT may benefit other compu...

  6. Stochastic tasks: difficulty and Levin search

    OpenAIRE

    Hernández Orallo, José

    2015-01-01

    We establish a setting for asynchronous stochastic tasks that account for episodes, rewards and responses, and, most especially, the computational complexity of the algorithm behind an agent solving a task. This is used to determine the difficulty of a task as the (logarithm of the) number of computational steps required to acquire an acceptable policy for the task, which includes the exploration of policies and their verification. We also analyse instance difficulty, task c...

  7. Task duration in contextual interference.

    Science.gov (United States)

    Smith, Peter J K

    2002-12-01

    Duration of practice trial on a pursuit rotor task in contextual interference was investigated. Participants practiced at each of 4 angular velocities, with 24 participants completing 28 trials lasting 20 sec., and 24 participants completing 112 trials of 5 sec. Half of the participants in each trial-duration condition practiced in a blocked format and half practiced in a random format. After random practice posttest performance was better than blocked practice when practice-trial duration was 20 sec., but worse when practice-trial duration was 5 sec. This result is not consistent with theoretical explanations of the contextual interference effect and is discussed with reference to the task characteristics and demands of the pursuit rotor. PMID:12578255

  8. Task-oriented situation recognition

    Science.gov (United States)

    Bauer, Alexander; Fischer, Yvonne

    2010-04-01

    From the advances in computer vision methods for the detection, tracking and recognition of objects in video streams, new opportunities for video surveillance arise: In the future, automated video surveillance systems will be able to detect critical situations early enough to enable an operator to take preventive actions, instead of using video material merely for forensic investigations. However, problems such as limited computational resources, privacy regulations and a constant change in potential threads have to be addressed by a practical automated video surveillance system. In this paper, we show how these problems can be addressed using a task-oriented approach. The system architecture of the task-oriented video surveillance system NEST and an algorithm for the detection of abnormal behavior as part of the system are presented and illustrated for the surveillance of guests inside a video-monitored building.

  9. Fuel oil quality task force

    Energy Technology Data Exchange (ETDEWEB)

    Laisy, J.; Turk, V. [R.W. Beckett Corp., Elyria, OH (United States)

    1997-09-01

    In April, 1996, the R.W. Beckett Corporation became aware of a series of apparently unrelated symptoms that made the leadership of the company concerned that there could be a fuel oil quality problem. A task force of company employees and industry consultants was convened to address the topic of current No. 2 heating oil quality and its effect on burner performance. The task force studied changes in fuel oil specifications and trends in properties that have occurred over the past few years. Experiments were performed at Beckett and Brookhaven National Laboratory to understand the effect of changes in some fuel oil properties. Studies by other groups were reviewed, and field installations were inspected to gain information about the performance of fuel oil that is currently being used in the U.S. and Canada. There was a special concern about the use of red dye in heating oils and the impact of sulfur levels due to the October, 1993 requirement of low sulfur (<0.05%) for on-highway diesel fuel. The results of the task force`s efforts were published in July, 1996. The primary conclusion of the task force was that there is not a crisis or widespread general problem with fuel oil quality. Localized problems that were seen may have been related to refinery practices and/or non-traditional fuel sources. System cleanliness is very important and the cause of many oil burner system problems. Finally, heating oil quality should get ongoing careful attention by Beckett engineering personnel and heating oil industry groups.

  10. Task Specialization, Immigration, and Wages

    OpenAIRE

    Peri, Giovanni; Sparber, Chad

    2008-01-01

    Many workers with low levels of educational attainment immigrated to the United States in recent decades. Large inflows of less-educated immigrants would reduce wages paid to comparably-educated native-born workers if the two groups are perfectly substitutable in production. In a simple model exploiting comparative advantage, however, we show that if less-educated foreign and native-born workers specialize in performing different tasks, immigration will cause natives to reallocate their...

  11. Multi-Task Collaboration CPS Modeling Based on Immune Feedback

    Directory of Open Access Journals (Sweden)

    Haiying Li

    2013-09-01

    Full Text Available In this paper, a dynamic multi-task collaboration CPS control model based on the self-adaptive immune feedback is proposed and implemented in the smart home environment. First, the internal relations between CPS and the biological immune system are explored via their basic theories. Second, CPS control mechanism is elaborated through the analysis of CPS control structure. Finally, a comprehensive strategy for support is introduced into multi-task collaboration to improve the dynamic cognitive ability. At the same time, the performance of parameters is correspondingly increased by the operator of the antibody concentration and the selective pressure. Furthermore, the model has been put into service in the smart home laboratory. The experimental results show that this model can integrate user’s needs into the environment for properly regulating the home environment.

  12. 78 FR 27969 - Meeting of the Community Preventive Services Task Force (Task Force)

    Science.gov (United States)

    2013-05-13

    ... Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention (CDC), Department of Health... Prevention (CDC) announces the next meeting of the Community Preventive Services Task Force (Task Force). The Task Force is independent and nonfederal. Its members are nationally known leaders in public...

  13. 78 FR 63208 - UPDATE-Meeting of the Community Preventive Services Task Force (Task Force)

    Science.gov (United States)

    2013-10-23

    ... Services Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention (CDC), Department of... Force (Task Force). The in-person Task Force meeting is being replaced by an abbreviated conference call... necessary scientific and logistical support for the meeting. The Task Force is an independent,......

  14. 78 FR 2996 - Meeting of the Community Preventive Services Task Force (Task Force)

    Science.gov (United States)

    2013-01-15

    ... Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention (CDC), Department of Health... Prevention (CDC) announces the next meeting of the Community Preventive Services Task Force (Task Force). The Task Force is independent and nonfederal. Its members are nationally known leaders in public...

  15. 77 FR 56845 - Meeting of the Community Preventive Services Task Force (Task Force)

    Science.gov (United States)

    2012-09-14

    ... Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention (CDC), Department of Health... Prevention (CDC) announces the next meeting of the Community Preventive Services Task Force (Task Force). The Task Force is independent and nonfederal. Its members are nationally known leaders in public...

  16. 78 FR 59939 - Meeting of the Community Preventive Services Task Force (Task Force)

    Science.gov (United States)

    2013-09-30

    ... Task Force (Task Force) AGENCY: Centers for Disease Control and Prevention (CDC), Department of Health..., announcing the next meeting of the Community Preventive Services Task Force (Task Force). The document did... inability to attend the Task Force meeting due to the strict security regulations on federal...

  17. Learner-Learner Interaction during Collaborative Pragmatic Tasks: The Role of Cognitive and Pragmatic Task Demands

    Science.gov (United States)

    Kim, YouJin; Taguchi, Naoko

    2016-01-01

    Previous task complexity studies have suggested that learners produce more negotiation of meaning opportunities during complex tasks than simple tasks (Robinson, 2011). The present study builds on the existing task complexity literature by examining the impact of task complexity and pragmatic situational demands on the number of learning…

  18. Advance Reservation of Resources for Task Execution in Grid Environments

    CERN Document Server

    Moise, Eliza; Pop, Florin; Cristea, Valentin

    2011-01-01

    The paper proposes a solution for the Grid scheduling problem, addressing in particular the requirement of high performance an efficient algorithm must fulfill. Advance Reservation engages a distributed, dynamic, fault-tolerant and efficient strategy which reserves resources for future task execution. The paper presents the main features of the strategy, the functioning mechanism the strategy is based on and the methods used for evaluating the algorithm.

  19. Static and dynamic task mapping onto network on chip multiprocessors

    Directory of Open Access Journals (Sweden)

    Freddy Bolaños-Martínez

    2014-01-01

    Full Text Available Las redes en circuito integrado (NoC representan un importante paradigma de uso creciente para los sistemas multiprocesador en circuito integrado (MPSoC, debido a su flexibilidad y escalabilidad. Las estrategias de tolerancia a fallos han venido adquiriendo importancia, a medida que los procesos de manufactura incursionan en dimensiones por debajo del micrómetro y la complejidad de los diseños aumenta. Este artículo describe un algoritmo de aprendizaje incremental basado en población (PBIL, orientado a optimizar el proceso de mapeo en tiempo de diseño, así como a encontrar soluciones de mapeo óptimas en tiempo de ejecución, para hacer frente a fallos de único nodo en la red. En ambos casos, los objetivos de optimización corresponden al tiempo de ejecución de las aplicaciones y al ancho de banda pico que aparece en la red. Las simulaciones se basaron en un algoritmo de ruteo XY determinístico, operando sobre una topología de malla 2D para la NoC. Los resultados obtenidos son prometedores. El algoritmo propuesto exhibe un desempeño superior a otras técnicas reportadas cuando el tamaño del problema aumenta.

  20. 职业性噪声致双耳高频听损人群心血管疾病相关指标的调查%Cardiovascular Disease Related Indices in Workers with Occupational Noise Induced Binaural High Frequency Hearing Loss

    Institute of Scientific and Technical Information of China (English)

    钟皓成; 邵玉仙; 陈伟勤

    2013-01-01

    [目的]调查职业性噪声致双耳高频听损人群的心血管疾病相关指标. [方法]以某火力发电厂工人为研究对象,排除有心脑血管、肝、肾等重大疾病史,高血压、糖尿病、冠心病家族史及酗酒史,研究对象共126例.按双耳高频听阈分为对照组[≤25 dB(HL),64例]、轻度损伤组[26~40dB(HL),39例]、重度损伤组[≥41dB(HL),23例].分析每组人员的空腹血糖、血胆固醇、血三酰甘油、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇含量及高血压患病率、ST段压低阳性率. [结果]随双耳高频听阈增加,各组间血胆固醇、空腹血糖含量及高血压患病率、ST段压低阳性率呈增高趋势(P<0.05).轻度、重度损伤组中血三酰甘油明显高于对照组(P<0.05).高密度脂蛋白胆固醇、低密度脂蛋白胆固醇在各组间差异无统计学意义(P>0.05). [结论]双耳高频听阈损伤可能与某些心血管疾病相关指标存在不同程度的相互作用,保护噪声从业人员听力可能是降低心血管疾病危险因素的职业措施.%[ Objective ] To identify cardiovascular disease related indices in workers with occupational noise induced binaural high frequency hearing loss. [ Methods ] After excluding those with history of cardiovascular, liver, kidney diseases, family history of hypertension, diabetes, coronary heart diseases, and history of alcohol abuse, 126 workers in a thermal power plant were enrolled in the study. The subjects were divided into control group [ ≤ 25 dB (hearing loss range, HL), 64 cases ], mild injury group [ 26-40 dB (HL), 39 cases ], and severe injury group [ ≤41 dB (HL), 23 cases ] according to binaural high frequency hearing threshold test. Fasting plasma glucose (FPG), total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), hypertension prevalence, and ST-segment depression positive rate were analyzed

  1. Computability and dynamical systems

    OpenAIRE

    Buescu, Jorge; Graça, Daniel; Zhong, Ning

    2011-01-01

    In this paper we explore results that establish a link between dynamical systems and computability theory (not numerical analysis). In the last few decades, computers have increasingly been used as simulation tools for gaining insight into dynamical behavior. However, due to the presence of errors inherent in such numerical simulations, with few exceptions, computers have not been used for the nobler task of proving mathematical results. Nevertheless, there have been some recen...

  2. Machine learning analysis of binaural rowing sounds

    DEFF Research Database (Denmark)

    Johard, Leonard; Ruffaldi, Emanuele; Hoffmann, Pablo F.;

    2011-01-01

    Techniques for machine hearing are increasing their potentiality due to new application domains. In this work we are addressing the analysis of rowing sounds in natural context for the purpose of supporting a training system based on virtual environments. This paper presents the acquisition metho...... methodology and the evaluation of different machine learning techniques for classifying rowing-sound data. We see that a combination of principal component analysis and shallow networks perform equally well as deep architectures, while being much faster to train....

  3. Machine Learning Analysis of Binaural Rowing Sounds

    OpenAIRE

    Filippeschi Alessandro; Hoffmann Pablo; Ruffaldi Emanuele; Johard Leonard

    2011-01-01

    Techniques for machine hearing are increasing their potentiality due to new application domains. In this work we are addressing the analysis of rowing sounds in natural context for the purpose of supporting a training system based on virtual environments. This paper presents the acquisition methodology and the evaluation of different machine learning techniques for classifying rowing-sound data. We see that a combination of principal component analysis and shallow networks perform equally wel...

  4. Machine Learning Analysis of Binaural Rowing Sounds

    Directory of Open Access Journals (Sweden)

    Filippeschi Alessandro

    2011-12-01

    Full Text Available Techniques for machine hearing are increasing their potentiality due to new application domains. In this work we are addressing the analysis of rowing sounds in natural context for the purpose of supporting a training system based on virtual environments. This paper presents the acquisition methodology and the evaluation of different machine learning techniques for classifying rowing-sound data. We see that a combination of principal component analysis and shallow networks perform equally well as deep architectures, while being much faster to train.

  5. Impedance learning for robotic contact tasks using natural actor-critic algorithm.

    Science.gov (United States)

    Kim, Byungchan; Park, Jooyoung; Park, Shinsuk; Kang, Sungchul

    2010-04-01

    Compared with their robotic counterparts, humans excel at various tasks by using their ability to adaptively modulate arm impedance parameters. This ability allows us to successfully perform contact tasks even in uncertain environments. This paper considers a learning strategy of motor skill for robotic contact tasks based on a human motor control theory and machine learning schemes. Our robot learning method employs impedance control based on the equilibrium point control theory and reinforcement learning to determine the impedance parameters for contact tasks. A recursive least-square filter-based episodic natural actor-critic algorithm is used to find the optimal impedance parameters. The effectiveness of the proposed method was tested through dynamic simulations of various contact tasks. The simulation results demonstrated that the proposed method optimizes the performance of the contact tasks in uncertain conditions of the environment. PMID:19696001

  6. The use of digital technology in finding multiple paths to solve and extend an equilateral triangle task

    Science.gov (United States)

    Santos-Trigo, Manuel; Reyes-Rodriguez, Aaron

    2016-01-01

    Mathematical tasks are crucial elements for teachers to orient, foster and assess students' processes to comprehend and develop mathematical knowledge. During the process of working and solving a task, searching for or discussing multiple solution paths becomes a powerful strategy for students to engage in mathematical thinking. A simple task that involves the construction of an equilateral triangle is used to present and discuss multiple solution approaches that rely on a variety of concepts and ways of reasoning. To this end, the use of a Dynamic Geometry System (GeoGebra) became instrumental in constructing and exploring dynamic models of the task. These model explorations provided a means to generate novel mathematical results.

  7. Task descriptions versus use cases

    DEFF Research Database (Denmark)

    Lauesen, Søren; Kuhail, Mohammad Amin

    2011-01-01

    Use cases are widely used as a substantial part of requirements, also when little programming is expected (COTS-based systems, Commercial-Off-The-Shelf). Are use cases effective as requirements? To answer this question, we invited professionals and researchers to specify requirements for the same...... project: Acquire a new system to support a hotline. Among the 15 replies, eight used traditional use cases that specified a dialog between user and system. Seven used a related technique, task description, which specified the customer’s needs without specifying a dialog. It also allowed the analyst to...

  8. Reactor safety - an international task

    International Nuclear Information System (INIS)

    The dimensions and the significance of the task of ensuring reactor safety can be defined on the basis of experiences gained from Harrisburg and Chernobyl. The countries that use nuclear energy are tied together to a community by virtue of the risk they share. Therefore the GRS is working in close cooperation with the EC, OECD, IAEO and COMECON. This results in safety examinations of the Greifswald reactor, safety analyses of nuclear reactors in Germany, France and the USA and also considerations on the safety demands to be placed on new reactor concepts. (DG)

  9. TASKS OF THE "INTENSIVE READING"

    Institute of Scientific and Technical Information of China (English)

    伍向梅

    1984-01-01

    @@ To Chinese students who are learning English as a foreign language, the "intensive reading" course is of great practical value,especially in the intermediate stage,i.e.senior-middle school or the second or third year in college. "Intensive reading"implies the recognition of the configuration, pronunciation, grammatical inflexion and structure of words, sentences, paragraphs, and the whole text. It strength ens listening and speaking, affords language, content, and models for writing.It helps the student lay a solid foundation of the language. Thus, the tasks assigned to the "intensive reading" are worth studying.

  10. U.S. Preventive Services Task Force

    Science.gov (United States)

    ... the USPSTF Our Members Conflict of Interest Disclosures Task Force 101 Resources Our Partners Reports to Congress Contact ... an effort to make the U.S. Preventive Services Task Force (USPSTF) recommendations clearer and its processes more transparent, ...

  11. U.S. Preventive Services Task Force

    Science.gov (United States)

    ... USPSTF Our Members Conflict of Interest Disclosures Task Force 101 Resources Our Partners Reports to Congress Contact ... effort to make the U.S. Preventive Services Task Force (USPSTF) recommendations clearer and its processes more transparent, ...

  12. Planning in Markov Stochastic Task Domains

    Directory of Open Access Journals (Sweden)

    Yong Lin

    2010-10-01

    Full Text Available In decision theoretic planning, a challenge for Markov decision processes (MDPs and partially observable Markov decision processes (POMDPs is, many problem domains contain big state spaces and complex tasks, which will result in poor solution performance. We develop a task analysis and modeling (TAM approach, in which the (POMDP model is separated into a task view and an action view. In the task view, TAM models the problem domain using a task equivalence model, with task-dependent abstract states and observations. We provide a learning algorithm to obtain the parameter values of task equivalence models. We present three typical examples to explain the TAM approach. Experimental results indicate our approach can greatly improve the computational capacity of task planning in Markov stochastic domains.

  13. Estimation of worst case latency of periodic tasks in a real time distributed environment

    Directory of Open Access Journals (Sweden)

    RAMESH BABU NIMMATOORI,

    2011-03-01

    Full Text Available Real-time computations require exact bounded response times. For relatively simple models of computation, it is possible to determine conditions under which it is theoretically possible to guarantee that an invocation of a task will complete its execution. But it is very much complicated to guarantee a response time for the periodic tasks that execute in a distributed system application. In a distributed system, the applications are aligned as a set of dependent tasks. Here, the time required for a message to pass from one task to the other is a function of the individual timelines. Each task further constitutes of subtasks related by data dependencies. Also, tightbounds are essential for the tasks because of the dynamic nature of the distributed systems. As the distributed systems have the hard real time deadlines, the task executions have to be completed before the specified deadline. Hence the estimation of the worst case latency for a task link is essential. And, as the task structure and the application system model are well known in advance, for the synthesis and verification of applicationspecific distributed systems this estimation is quite important. This paper proposes an approach to estimate the worst case latency of periodic tasks in a real time distributed system.

  14. Task-relevant modulation of primary somatosensory cortex suggests a prefrontal-cortical sensory gating system.

    Science.gov (United States)

    Schaefer, Michael; Heinze, Hans-Jochen; Rotte, Michael

    2005-08-01

    Increasing evidence suggests that somatosensory information is modulated cortically for task-specific sensory inflow: Several studies report short-term adaptation of representational maps in primary somatosensory cortex (SI) due to attention or induced by task-related motor activity such as handwriting. Recently, it has been hypothesized that the frontal or prefrontal cortex may modulate SI. In order to test this hypothesis, we studied the functional organization of SI while subjects performed the Tower of Hanoi task. This task is known to be related to activation of frontal or prefrontal areas. The functional organization of SI while performing the Tower of Hanoi task was compared to the organization of SI during performing the same movements but without the Tower of Hanoi task and with rest. Topography of SI was assessed using neuromagnetic source imaging based on tactile stimulation of the first (D1) and fifth digits (D5). Performing the Tower of Hanoi task was accompanied by plastic changes in SI as indicated by significant shifts in the cortical representations of D1 and D5: They moved further apart during the Tower of Hanoi task compared to the control task containing the same movements but without the cognitive characteristic. Thus, we conclude that SI maps undergo dynamic modulation depending on motor tasks with different cognitive demands. The results suggest that this short-term plasticity may be regulated by a prefrontal-cortical sensory gating system. PMID:15886021

  15. An overview of task order 10

    Energy Technology Data Exchange (ETDEWEB)

    Rousculp, Christopher L [Los Alamos National Laboratory

    2011-01-12

    Task Order 10 formalizes a collaboration in high explosive pulsed power (HEPP) experiments between LANL and VNIIEF. The focus is the VNIIEF disk explosive magnetic generator (DEMG) technology. The task order outlines a sequence of tasks and deliverables culminating in an experiment which takes place in the US utilizing US explosives and a Russian DEMG. This talk summarizes task order 10. It gives a brief history and present status in terms of the proposed high pressure EOS experiment (ALT-3).

  16. Multi-task Sequence to Sequence Learning

    OpenAIRE

    Luong, Minh-Thang; Le, Quoc V.; Sutskever, Ilya; Vinyals, Oriol; Kaiser, Lukasz

    2015-01-01

    Sequence to sequence learning has recently emerged as a new paradigm in supervised learning. To date, most of its applications focused on only one task and not much work explored this framework for multiple tasks. This paper examines three multi-task learning (MTL) settings for sequence to sequence models: (a) the oneto-many setting - where the encoder is shared between several tasks such as machine translation and syntactic parsing, (b) the many-to-one setting - useful when only the decoder ...

  17. Task Manager for the Motorola 6800

    International Nuclear Information System (INIS)

    A nucleus of multi-tasking operating systems has been implemented on a Motorola 6800 microprocessor. This control structure, called a Task Manager, is appropriate for those real-time systems which are required to handle several different asynchronous events. The general concept of a Task Manager is described. A specific implementation for a Motorola 6800 microprocessor is given and its usage defined

  18. Working Memory Costs of Task Switching

    Science.gov (United States)

    Liefooghe, Baptist; Barrouillet, Pierre; Vandierendonck, Andre; Camos, Valerie

    2008-01-01

    Although many accounts of task switching emphasize the importance of working memory as a substantial source of the switch cost, there is a lack of evidence demonstrating that task switching actually places additional demands on working memory. The present study addressed this issue by implementing task switching in continuous complex span tasks…

  19. Research on Task-Based Language Teaching

    Institute of Scientific and Technical Information of China (English)

    赵玲玲

    2014-01-01

    This paper begins with a brief introduction to Task-Based Language Teaching(TBLT).The Task-Based Language Teaching(TBLA) has gained popularity in the field of language teaching since the last decade of the 20th century.This paper mainly il ustrates the definition,importance and approaches of Task-Based Language Teaching(TBLA).

  20. Core Task and Organizational Reality

    DEFF Research Database (Denmark)

    Vikkelsø, Signe

    2015-01-01

    Reflecting a wider trend in the social sciences, the field of organization studies has adopted an increasingly general and metaphysical vocabulary to guide and frame its analyses of life and dynamics in organizations. Where classic organizational analyses would describe organizations in terms...

  1. Robust visual tracking via structured multi-task sparse learning

    KAUST Repository

    Zhang, Tianzhu

    2012-11-09

    In this paper, we formulate object tracking in a particle filter framework as a structured multi-task sparse learning problem, which we denote as Structured Multi-Task Tracking (S-MTT). Since we model particles as linear combinations of dictionary templates that are updated dynamically, learning the representation of each particle is considered a single task in Multi-Task Tracking (MTT). By employing popular sparsity-inducing lp,q mixed norms (specifically p∈2,∞ and q=1), we regularize the representation problem to enforce joint sparsity and learn the particle representations together. As compared to previous methods that handle particles independently, our results demonstrate that mining the interdependencies between particles improves tracking performance and overall computational complexity. Interestingly, we show that the popular L1 tracker (Mei and Ling, IEEE Trans Pattern Anal Mach Intel 33(11):2259-2272, 2011) is a special case of our MTT formulation (denoted as the L11 tracker) when p=q=1. Under the MTT framework, some of the tasks (particle representations) are often more closely related and more likely to share common relevant covariates than other tasks. Therefore, we extend the MTT framework to take into account pairwise structural correlations between particles (e.g. spatial smoothness of representation) and denote the novel framework as S-MTT. The problem of learning the regularized sparse representation in MTT and S-MTT can be solved efficiently using an Accelerated Proximal Gradient (APG) method that yields a sequence of closed form updates. As such, S-MTT and MTT are computationally attractive. We test our proposed approach on challenging sequences involving heavy occlusion, drastic illumination changes, and large pose variations. Experimental results show that S-MTT is much better than MTT, and both methods consistently outperform state-of-the-art trackers. © 2012 Springer Science+Business Media New York.

  2. Dynamic reweighting of three modalities for sensor fusion.

    Directory of Open Access Journals (Sweden)

    Sungjae Hwang

    Full Text Available We simultaneously perturbed visual, vestibular and proprioceptive modalities to understand how sensory feedback is re-weighted so that overall feedback remains suited to stabilizing upright stance. Ten healthy young subjects received an 80 Hz vibratory stimulus to their bilateral Achilles tendons (stimulus turns on-off at 0.28 Hz, a ± 1 mA binaural monopolar galvanic vestibular stimulus at 0.36 Hz, and a visual stimulus at 0.2 Hz during standing. The visual stimulus was presented at different amplitudes (0.2, 0.8 deg rotation about ankle axis to measure: the change in gain (weighting to vision, an intramodal effect; and a change in gain to vibration and galvanic vestibular stimulation, both intermodal effects. The results showed a clear intramodal visual effect, indicating a de-emphasis on vision when the amplitude of visual stimulus increased. At the same time, an intermodal visual-proprioceptive reweighting effect was observed with the addition of vibration, which is thought to change proprioceptive inputs at the ankles, forcing the nervous system to rely more on vision and vestibular modalities. Similar intermodal effects for visual-vestibular reweighting were observed, suggesting that vestibular information is not a "fixed" reference, but is dynamically adjusted in the sensor fusion process. This is the first time, to our knowledge, that the interplay between the three primary modalities for postural control has been clearly delineated, illustrating a central process that fuses these modalities for accurate estimates of self-motion.

  3. Dynamic reweighting of three modalities for sensor fusion.

    Science.gov (United States)

    Hwang, Sungjae; Agada, Peter; Kiemel, Tim; Jeka, John J

    2014-01-01

    We simultaneously perturbed visual, vestibular and proprioceptive modalities to understand how sensory feedback is re-weighted so that overall feedback remains suited to stabilizing upright stance. Ten healthy young subjects received an 80 Hz vibratory stimulus to their bilateral Achilles tendons (stimulus turns on-off at 0.28 Hz), a ± 1 mA binaural monopolar galvanic vestibular stimulus at 0.36 Hz, and a visual stimulus at 0.2 Hz during standing. The visual stimulus was presented at different amplitudes (0.2, 0.8 deg rotation about ankle axis) to measure: the change in gain (weighting) to vision, an intramodal effect; and a change in gain to vibration and galvanic vestibular stimulation, both intermodal effects. The results showed a clear intramodal visual effect, indicating a de-emphasis on vision when the amplitude of visual stimulus increased. At the same time, an intermodal visual-proprioceptive reweighting effect was observed with the addition of vibration, which is thought to change proprioceptive inputs at the ankles, forcing the nervous system to rely more on vision and vestibular modalities. Similar intermodal effects for visual-vestibular reweighting were observed, suggesting that vestibular information is not a "fixed" reference, but is dynamically adjusted in the sensor fusion process. This is the first time, to our knowledge, that the interplay between the three primary modalities for postural control has been clearly delineated, illustrating a central process that fuses these modalities for accurate estimates of self-motion. PMID:24498252

  4. Studying Different Tasks of Implicit Learning across Multiple Test Sessions Conducted on the Web

    Science.gov (United States)

    Sævland, Werner; Norman, Elisabeth

    2016-01-01

    Implicit learning is usually studied through individual performance on a single task, with the most common tasks being the Serial Reaction Time (SRT) task, the Dynamic System Control (DSC) task, and Artificial Grammar Learning (AGL). Few attempts have been made to compare performance across different implicit learning tasks within the same study. The current study was designed to explore the relationship between performance on the DSC Sugar factory task and the Alternating Serial Reaction Time (ASRT) task. We also addressed another limitation of traditional implicit learning experiments, namely that implicit learning is usually studied in laboratory settings over a restricted time span lasting for less than an hour. In everyday situations, implicit learning is assumed to involve a gradual accumulation of knowledge across several learning episodes over a longer time span. One way to increase the ecological validity of implicit learning experiments could be to present the learning material repeatedly across shorter test sessions. This can most easily be done by using a web-based setup in which participants can access the material from home. We therefore created an online web-based system for measuring implicit learning that could be administered in either single or multiple sessions. Participants (n = 66) were assigned to either a single session or a multiple session condition. Learning occurred on both tasks, and awareness measures suggested that acquired knowledge was not fully conscious on either of the tasks. Learning and the degree of conscious awareness of the learned regularities were compared across conditions and tasks. On the DSC task, performance was not affected by whether learning had taken place in one or over multiple sessions. On the ASRT task, RT improvement across blocks was larger in the multiple-session condition. Learning in the two tasks was not related. PMID:27375512

  5. Multi-robot task allocation for exploration

    Institute of Scientific and Technical Information of China (English)

    GAO Ping-an; CAI Zi-xing

    2006-01-01

    The problem of allocating a number of exploration tasks to a team of mobile robots in dynamic environments was studied. The team mission is to visit several distributed targets. The path cost of target is proportional to the distance that a robot has to move to visit the target. The team objective is to minimize the average path cost of target over all targets. Finding an optimal allocation is strongly NP-hard. The proposed algorithm can produce a near-optimal solution to it. The allocation can be cast in terms of a multi-round single-item auction by which robots bid on targets. In each auction round, one target is assigned to a robot that produces the lowest path cost of the target. The allocated targets form a forest where each tree corresponds a robot's exploring targets set. Each robot constructs an exploring path through depth-first search in its target tree. The time complexity of the proposed algorithm is polynomial. Simulation experiments show that the allocating method is valid.

  6. Assessing Cognitive Load on Web Search Tasks

    CERN Document Server

    Gwizdka, Jacek

    2010-01-01

    Assessing cognitive load on web search is useful for characterizing search system features and search tasks with respect to their demands on the searcher's mental effort. It is also helpful for examining how individual differences among searchers (e.g. cognitive abilities) affect the search process. We examined cognitive load from the perspective of primary and secondary task performance. A controlled web search study was conducted with 48 participants. The primary task performance components were found to be significantly related to both the objective and the subjective task difficulty. However, the relationship between objective and subjective task difficulty and the secondary task performance measures was weaker than expected. The results indicate that the dual-task approach needs to be used with caution.

  7. Garbage Collection Scheduling of Aperiodic Tasks

    Institute of Scientific and Technical Information of China (English)

    Ning Zhang; Guang-Ze Xiong

    2009-01-01

    In the previous work of garbage collection (GC) models, scheduling analysis was given based on an assumption that there were no aperiodic mutator tasks. However, it is not true in practical real-time systems. The GC algorithm which can schedule aperiodic tasks is proposed, and the variance of live memory is analyzed. In this algorithm, active tasks are deferred to be processed by GC until the states of tasks become inactive, and the saved sporadic server time can be used to schedule aperiodic tasks. Scheduling the sample task sets demonstrates that this algorithm in this paper can schedule aperiodic tasks and decrease GC work. Thus, the GC algorithm proposed is more flexible and portable.

  8. Adapting Non-Task-Based Materials to Fit a Task-Based Framework

    Institute of Scientific and Technical Information of China (English)

    郑海英

    2007-01-01

    Analyzes the three -phases--pre -task, task cycle, post -task and their rationale in task -based language teaching, designs corresponding teaching activities after adapting one text from New Horizon College English, so that college English teachers can better understand and use this teaching approach, and then improve the teaching effect and college students'comprehensive application abilities of language.

  9. Is Performance in Task-Cuing Experiments Mediated by Task Set Selection or Associative Compound Retrieval?

    Science.gov (United States)

    Forrest, Charlotte L. D.; Monsell, Stephen; McLaren, Ian P. L.

    2014-01-01

    Task-cuing experiments are usually intended to explore control of task set. But when small stimulus sets are used, they plausibly afford learning of the response associated with a combination of cue and stimulus, without reference to tasks. In 3 experiments we presented the typical trials of a task-cuing experiment: a cue (colored shape) followed,…

  10. Is a "Complex" Task Really Complex? Validating the Assumption of Cognitive Task Complexity

    Science.gov (United States)

    Sasayama, Shoko

    2016-01-01

    In research on task-based learning and teaching, it has traditionally been assumed that differing degrees of cognitive task complexity can be inferred through task design and/or observations of differing qualities in linguistic production elicited by second language (L2) communication tasks. Without validating this assumption, however, it is…

  11. Robust Task Space Trajectory Tracking Control of Robotic Manipulators

    Science.gov (United States)

    Galicki, M.

    2016-08-01

    This work deals with the problem of the accurate task space trajectory tracking subject to finite-time convergence. Kinematic and dynamic equations of a redundant manipulator are assumed to be uncertain. Moreover, globally unbounded disturbances are allowed to act on the manipulator when tracking the trajectory by the end-effector. Furthermore, the movement is to be accomplished in such a way as to reduce both the manipulator torques and their oscillations thus eliminating the potential robot vibrations. Based on suitably defined task space non-singular terminal sliding vector variable and the Lyapunov stability theory, we propose a class of chattering-free robust controllers, based on the estimation of transpose Jacobian, which seem to be effective in counteracting both uncertain kinematics and dynamics, unbounded disturbances and (possible) kinematic and/or algorithmic singularities met on the robot trajectory. The numerical simulations carried out for a redundant manipulator of a SCARA type consisting of the three revolute kinematic pairs and operating in a two-dimensional task space, illustrate performance of the proposed controllers as well as comparisons with other well known control schemes.

  12. Task-and-role-based access-control model for computational grid

    Institute of Scientific and Technical Information of China (English)

    LONG Tao; HONG Fan; WU Chi; SUN Ling-li

    2007-01-01

    Access control in a grid environment is a challenging issue because the heterogeneous nature and independent administration of geographically dispersed resources in grid require access control to use fine-grained policies. We established a task-and-role-based access-control model for computational grid (CG-TRBAC model), integrating the concepts of role-based access control (RBAC) and task-based access control (TBAC). In this model, condition restrictions are defined and concepts specifically tailored to Workflow Management System are simplified or omitted so that role assignment and security administration fit computational grid better than traditional models; permissions are mutable with the task status and system variables, and can be dynamically controlled. The CG-TRBAC model is proved flexible and extendible. It can implement different control policies. It embodies the security principle of least privilege and executes active dynamic authorization. A task attribute can be extended to satisfy different requirements in a real grid system.

  13. Assessing Task Migration Impact on Embedded Soft Real-Time Streaming Multimedia Applications

    Directory of Open Access Journals (Sweden)

    Alimonda Andrea

    2008-01-01

    Full Text Available Abstract Multiprocessor systems on chips (MPSoCs are envisioned as the future of embedded platforms such as game-engines, smart-phones and palmtop computers. One of the main challenge preventing the widespread diffusion of these systems is the efficient mapping of multitask multimedia applications on processing elements. Dynamic solutions based on task migration has been recently explored to perform run-time reallocation of task to maximize performance and optimize energy consumption. Even if task migration can provide high flexibility, its overhead must be carefully evaluated when applied to soft real-time applications. In fact, these applications impose deadlines that may be missed during the migration process. In this paper we first present a middleware infrastructure supporting dynamic task allocation for NUMA architectures. Then we perform an extensive characterization of its impact on multimedia soft real-time applications using a software FM Radio benchmark.

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

    Directory of Open Access Journals (Sweden)

    Glória Cravo

    2015-01-01

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

  15. Assessing Task Migration Impact on Embedded Soft Real-Time Streaming Multimedia Applications

    Directory of Open Access Journals (Sweden)

    Andrea Acquaviva

    2008-01-01

    Full Text Available Multiprocessor systems on chips (MPSoCs are envisioned as the future of embedded platforms such as game-engines, smart-phones and palmtop computers. One of the main challenge preventing the widespread diffusion of these systems is the efficient mapping of multitask multimedia applications on processing elements. Dynamic solutions based on task migration has been recently explored to perform run-time reallocation of task to maximize performance and optimize energy consumption. Even if task migration can provide high flexibility, its overhead must be carefully evaluated when applied to soft real-time applications. In fact, these applications impose deadlines that may be missed during the migration process. In this paper we first present a middleware infrastructure supporting dynamic task allocation for NUMA architectures. Then we perform an extensive characterization of its impact on multimedia soft real-time applications using a software FM Radio benchmark.

  16. On the importance of Task 1 and error performance measures in PRP dual-task studies.

    Science.gov (United States)

    Strobach, Tilo; Schütz, Anja; Schubert, Torsten

    2015-01-01

    The psychological refractory period (PRP) paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and Task 2) are presented with variable stimulus onset asynchronies (SOAs) and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e., decreasing SOAs do not increase reaction times (RTs) and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates) show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/or error rates in Task 1). This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects. PMID:25904890

  17. A Spatial Queuing-Based Algorithm for Multi-Robot Task Allocation

    Directory of Open Access Journals (Sweden)

    William Lenagh

    2015-08-01

    Full Text Available Multi-robot task allocation (MRTA is an important area of research in autonomous multi-robot systems. The main problem in MRTA is to allocate a set of tasks to a set of robots so that the tasks can be completed by the robots while ensuring that a certain metric, such as the time required to complete all tasks, or the distance traveled, or the energy expended by the robots is reduced. We consider a scenario where tasks can appear dynamically and a task needs to be performed by multiple robots to be completed. We propose a new algorithm called SQ-MRTA (Spatial Queueing-MRTA that uses a spatial queue-based model to allocate tasks between robots in a distributed manner. We have implemented the SQ-MRTA algorithm on accurately simulated models of Corobot robots within the Webots simulator for different numbers of robots and tasks and compared its performance with other state-of-the-art MRTA algorithms. Our results show that the SQ-MRTA algorithm is able to scale up with the number of tasks and robots in the environment, and it either outperforms or performs comparably with respect to other distributed MRTA algorithms.

  18. The task complexity experiment 2003/2004

    International Nuclear Information System (INIS)

    The purpose of this experiment was to explore how additional tasks added to base case scenarios affected the operators' performance of the main tasks. These additional tasks were in different scenario variants intended to cause high time pressure, high information load, and high masking. The experiment was run in Halden Man-Machine Laboratory's BWR simulator. Seven crews participated, each for one week. There were three operators in each crew. Five main types of scenarios and 20 scenario variants were run. The data from the experiment were analysed by completion time for important actions and by in-depth qualitative analyses of the crews' communications. The results showed that high time pressure decreased some of the crews' performance in the scenarios. When a crew had problems in solving a task for which the time pressure was high, they had even more problems in solving other important tasks. High information load did not affect the operators' performance much and in general the crews were very good at selecting the most important tasks in the scenarios. The scenarios that included both high time pressure and high information load resulted in more reduced performance for the crews compared to the scenarios that only included high time pressure. The total amount of tasks to do and information load to attend to seemed to affect the crews' performance. To solve the scenarios with high time pressure well, it was important to have good communication and good allocation of tasks within the crew. Furthermore, the results showed that scenarios with an added complex, masked task created problems for some crews when solving a relatively simple main task. Overall, the results confirmed that complicating, but secondary tasks, that are not normally taken into account when modelling the primary tasks in a PRA scenario can adversely affect the performance of the main tasks modelled in the PRA scenario. (Author)

  19. Affective and Deliberative Processes in Risky Choice: Age Differences in Risk Taking in the Columbia Card Task

    NARCIS (Netherlands)

    Figner, B.C.; Mackinlay, R,J,; Wilkening, F.; Weber, E.U.

    2009-01-01

    The authors investigated risk taking and underlying information use in 13- to 16- and 17- to 19-year-old adolescents and in adults in 4 experiments, using a novel dynamic risk-taking task, the Columbia Card Task (CCT). The authors investigated risk taking under differential involvement of affective

  20. Affective and Deliberative Processes in Risky Choice: Age Differences in Risk Taking in the Columbia Card Task

    Science.gov (United States)

    Figner, Bernd; Mackinlay, Rachael J.; Wilkening, Friedrich; Weber, Elke U.

    2009-01-01

    The authors investigated risk taking and underlying information use in 13- to 16- and 17- to 19-year-old adolescents and in adults in 4 experiments, using a novel dynamic risk-taking task, the Columbia Card Task (CCT). The authors investigated risk taking under differential involvement of affective versus deliberative processes with 2 versions of…

  1. A Research of Task-based Language Teaching Applied to the College Oral English Teaching

    Institute of Scientific and Technical Information of China (English)

    王景琦; 祝菁

    2016-01-01

    Task-based Language Teaching has been greatly applied to college English teaching after the traditional “PPP”teaching approach. The key links in TBLT are assignment, development and inspection of tasks. With the main method, interactive communication,“students-centered ” is stressed, and students' subjective dynamics is fully exerted. Class time can be effectively used and students' communicative ability is cultivated with the improvement of oral expression ability.

  2. Interaction between articulatory gestures and inner speech in a counting task

    OpenAIRE

    Hadian Cefidekhanie, Ali; Savariaux, Christophe; Sato, Marc; Schwartz, Jean-Luc

    2014-01-01

    Interaction between covert and overt orofacial gestures has been poorly studied apart from old and rather qualitative experiments. The question deserves special interest in the context of the debate between auditory and motor theories of speech perception, where dual tasks may be of great interest. It is shown here that dynamic mandible and lips movement produced by a participant result in strong and stable perturbations to an inner speech counting task that has to be realized at the same tim...

  3. Training recurrent neural networks with sparse, delayed rewards for flexible decision tasks

    OpenAIRE

    Miconi, Thomas

    2015-01-01

    Recurrent neural networks in the chaotic regime exhibit complex dynamics reminiscent of high-level cortical activity during behavioral tasks. However, existing training methods for such networks are either biologically implausible, or require a real-time continuous error signal to guide the learning process. This is in contrast with most behavioral tasks, which only provide time-sparse, delayed rewards. Here we show that a biologically plausible reward-modulated Hebbian learning algorithm, pr...

  4. Stability and task complexity: a neural network model of genetic assimilation

    OpenAIRE

    Watson, J.; Geard, N; Wiles, J

    2002-01-01

    Since Hinton and Nowlan introduced the Baldwin effect to the evolutionary computation community, agent-based studies of genetic assimilation have uncovered many details of the dynamic processes involved. In a previous paper, we demonstrated genetic assimilation with a simple food/toxin discrimination task using neural network agents that could evolve their learning rate. The study reported in this paper investigated the genetic assimilation of more complex learning tasks. Kauffman's NK landsc...

  5. NIRS evaluates the thinking process of Mushi-kuizan task

    Science.gov (United States)

    Eda, Hideo; Kuroda, Yasufumi; Okamoto, Naoko; Maesako, Takanori

    2008-02-01

    We discuss the possibility of Near Infrared Spectroscopy (NIRS) application to the educational research. NIRS system was used for prefrontal cortex measurement of children, when they were solving Mushi-kuizan problems. The Mushi-kuizan task is one of the mathematical puzzles. Subjects were four children in fifth grade. Hemoglobin parameters such as oxygenated hemoglobin and deoxygenated hemoglobin were calculated during Mushi-kuizan problems. The parameters were compared with the performance data of each subject. Changes Hb parameters described how children use their brain. NIRS evaluated the thinking process of mathematics task. It is very useful for mathematics teachers to catch the children's thinking process dynamically because they can consider the way of teaching for each child. It was shown that NIRS may be able to apply to education.

  6. On the importance of Task 1 and error performance measures in PRP dual-task studies

    Directory of Open Access Journals (Sweden)

    Tilo eStrobach

    2015-04-01

    Full Text Available The Psychological Refractory Period (PRP paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and 2 are presented with variable stimulus onset asynchronies (SOAs and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e. decreasing SOAs do not increase RTs and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/ or error rates in Task 1. This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects.

  7. Task-Driven Activity Reduces the Cortical Activity Space of the Brain: Experiment and Whole-Brain Modeling.

    OpenAIRE

    Adrián Ponce-Alvarez; He, Biyu J.; Patric Hagmann; Gustavo Deco

    2015-01-01

    How a stimulus or a task alters the spontaneous dynamics of the brain remains a fundamental open question in neuroscience. One of the most robust hallmarks of task/stimulus-driven brain dynamics is the decrease of variability with respect to the spontaneous level, an effect seen across multiple experimental conditions and in brain signals observed at different spatiotemporal scales. Recently, it was observed that the trial-to-trial variability and temporal variance of functional magnetic reso...

  8. Unnecessary work tasks and mental health

    DEFF Research Database (Denmark)

    Madsen, Ida E H; Tripathi, Manisha; Borritz, Marianne;

    2014-01-01

    is modified by sex, age, occupational position, and baseline mental health status. METHODS: The data were obtained from self-administered questionnaires from 1351 Danish human service workers in three waves of data-collection during 1999-2005. We measured unnecessary work tasks by a single item, and assessed......OBJECTIVES: According to the "stress-as-offense-to-self" perspective, work tasks that are considered unnecessary or unreasonable - so-called "illegitimate work tasks" - are likely to elicit stress-reactions. Previous studies, mostly cross-sectional, have shown that illegitimate tasks are associated...... with increased self-reported stress, cortisol, and counterproductive work behavior. In this article, we examine the prospective association between unnecessary work tasks, one type of illegitimate work tasks, and mental health among Danish human service workers. Further, we explore whether this association...

  9. Designing CALL Tasks for College English Learners

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>As CALL(Computer Assisted Language Learning) became a new trend among China’s college English learners nowadays,it is time that teachers reflected on their teaching methodology innovation with the new technological advancement,one part of it is writing CALL tasks for their own individual classes.This paper presents a few basic principles and rationales of designing such tasks,and hope to work as a reminder for task writers.These principles and rationales include how to realize CLT(communicative language teaching) and learner-centredness and foster learner autonomy.In order to achieve this,it is reminded that task writers pay attention to a few points,like the communicativeness,contextualization,authenticity,and relatedness in task writing. Aspects of syllabus design,choice of texts,contents of activities and tasks and sequencing are put under investigation.

  10. Expressing Coarse-Grain Dependencies Among Tasks in Shared Memory Programs

    DEFF Research Database (Denmark)

    Larsen, Per; Karlsson, Sven; Madsen, Jan

    2011-01-01

    Designers of embedded systems face tight constraints on resources, response time and cost. The ability to analyze embedded systems is essential to timely delivery of new designs. Many analysis techniques model parallel programs as task graphs. Task graphs capture the worst-case execution times...... dependencies that do not occur at runtime. This lets tools compute more accurate task graphs from the annotated code. The correct use of the directives cannot be verified at compile time. Therefore, the check for correct use is done at runtime—not unlike dynamic array bounds checking in many languages...

  11. CDTOM: A Context-driven Task-oriented Middleware for Pervasive Homecare Environment

    Directory of Open Access Journals (Sweden)

    Hongbo Ni

    2011-02-01

    Full Text Available With the growing number of the elderly, we see a greater demand for home care, and the vision of pervasive computing is also floating into the domain of the household that aims to build a smart homewhich can assist inhabitants (users to live more conveniently and harmoniously. Such health-care pervasive applications in smart home should focus on the inhabitant’s goal or task in diverse situations,rather than the various complex devices and services. The core challenge for homecare design is to perceive the environment and assess occurring situations, thus allowing systems to behave intelligently according to the user’s intent. Due to the dynamic and heterogeneous nature of pervasive computing environment, it is difficult for an average user to obtain right information and service and in right place at right time. This paper proposes a context-driven task-oriented middleware (CDTOM to meet the challenge. The most important component is its task model that provides an adequate high-level description of user-oriented tasks and their related contexts. Leveraging the model multiple entities can easilyexchange, share and reuse their knowledge. Based on the hierarchy of task ontology, a novel task recognition approach using CBR (case-based reasoning is presented and the performance of taskrecognition is evaluated by task number, context size and time costing. Moreover, a dynamic mechanism for mapping the recognized task and services is also discussed. Finally, we present the design and implementation of our task supporting system (TSS to aid an inhabitant’s tasks in light of his lifestyle and environment conditions in pervasive homecare environment, and the results of the prototype system show that our middleware approach achieves good efficiency of context management and good accuracy ofuser’s activity inference, and can improve efficiently quality of user’s life.

  12. Common EEG features for behavioral estimation in disparate, real-world tasks.

    Science.gov (United States)

    Touryan, Jon; Lance, Brent J; Kerick, Scott E; Ries, Anthony J; McDowell, Kaleb

    2016-02-01

    In this study we explored the potential for capturing the behavioral dynamics observed in real-world tasks from concurrent measures of EEG. In doing so, we sought to develop models of behavior that would enable the identification of common cross-participant and cross-task EEG features. To accomplish this we had participants perform both simulated driving and guard duty tasks while we recorded their EEG. For each participant we developed models to estimate their behavioral performance during both tasks. Sequential forward floating selection was used to identify the montage of independent components for each model. Linear regression was then used on the combined power spectra from these independent components to generate a continuous estimate of behavior. Our results show that oscillatory processes, evidenced in EEG, can be used to successfully capture slow fluctuations in behavior in complex, multi-faceted tasks. The average correlation coefficients between the actual and estimated behavior was 0.548 ± 0.117 and 0.701 ± 0.154 for the driving and guard duty tasks respectively. Interestingly, through a simple clustering approach we were able to identify a number of common components, both neural and eye-movement related, across participants and tasks. We used these component clusters to quantify the relative influence of common versus participant-specific features in the models of behavior. These findings illustrate the potential for estimating complex behavioral dynamics from concurrent measures from EEG using a finite library of universal features. PMID:26748290

  13. Simultaneous Acquisition of Task and Feedback Models

    OpenAIRE

    Lopes, Manuel; Cederborg, Thomas; Oudeyer, Pierre-Yves

    2011-01-01

    International audience We present a system to learn task representations from ambiguous feedback. We consider an inverse reinforcement learner that receives feedback from a teacher with an unknown and noisy protocol. The system needs to estimate simultaneously what the task is (i.e. how to find a compact representation to the task goal), and how the teacher is providing the feedback. We further explore the problem of ambiguous protocols by considering that the words used by the teacher hav...

  14. Feasibility of the adaptive and automatic presentation of tasks (ADAPT system for rehabilitation of upper extremity function post-stroke

    Directory of Open Access Journals (Sweden)

    Choi Younggeun

    2011-08-01

    Full Text Available Abstract Background Current guidelines for rehabilitation of arm and hand function after stroke recommend that motor training focus on realistic tasks that require reaching and manipulation and engage the patient intensively, actively, and adaptively. Here, we investigated the feasibility of a novel robotic task-practice system, ADAPT, designed in accordance with such guidelines. At each trial, ADAPT selects a functional task according to a training schedule and with difficulty based on previous performance. Once the task is selected, the robot picks up and presents the corresponding tool, simulates the dynamics of the tasks, and the patient interacts with the tool to perform the task. Methods Five participants with chronic stroke with mild to moderate impairments (> 9 months post-stroke; Fugl-Meyer arm score 49.2 ± 5.6 practiced four functional tasks (selected out of six in a pre-test with ADAPT for about one and half hour and 144 trials in a pseudo-random schedule of 3-trial blocks per task. Results No adverse events occurred and ADAPT successfully presented the six functional tasks without human intervention for a total of 900 trials. Qualitative analysis of trajectories showed that ADAPT simulated the desired task dynamics adequately, and participants reported good, although not excellent, task fidelity. During training, the adaptive difficulty algorithm progressively increased task difficulty leading towards an optimal challenge point based on performance; difficulty was then continuously adjusted to keep performance around the challenge point. Furthermore, the time to complete all trained tasks decreased significantly from pretest to one-hour post-test. Finally, post-training questionnaires demonstrated positive patient acceptance of ADAPT. Conclusions ADAPT successfully provided adaptive progressive training for multiple functional tasks based on participant's performance. Our encouraging results establish the feasibility of ADAPT; its

  15. Task 7c: Worm tank

    International Nuclear Information System (INIS)

    Worm tank has a unique shape. In the seismic design of a worm tank, it is desirable to clear the behavior of the worm tank under the seismic loading. We assumed that there are two phenomena in the seismic behavior of the worm tank same as the behavior of the cylindrical and rectangular tanks. One is a sloshing behavior of the water and another is the dynamic response of the worm tank. In this study, we investigate the dynamic characteristics of the worm tank during the strong earthquakes. We conducted the vibration tests to clarify the seismic behaviors of the worm tanks and obtained the valuable data to verify the analytical method. It was found that the natural frequency can be calculated using the eigenvalue formula of the cylindrical and rectangular tanks. Lower modes of the worm tank are identical with that of the rectangular tank. We can estimate the surface behavior and the impact mode using the data of the rectangular tank. (author)

  16. Distributed fusion and automated sensor tasking in ISR systems

    Science.gov (United States)

    Preden, Jurgo; Pahtma, Raido; Astapov, Sergei; Ehala, Johannes; Riid, Andri; Motus, Leo

    2014-06-01

    Modern Intelligence, Surveillance and Reconnaissance (ISR) systems are increasingly being assembled from autonomous systems, so the resulting ISR system is a System of Systems (SoS). In order to take full advantage of the capabilities of the ISR SoS, the architecture and the design of these SoS should be able to facilitate the benefits inherent in a SoS approach - high resilience, higher level of adaptability and higher diversity, enabling on-demand system composition. The tasks performed by ISR SoS can well go beyond basic data acquisition, conditioning and communication as data processing can be easily integrated in the SoS. Such an ISR SoS can perform data fusion, classification and tracking (and conditional sensor tasking for additional data acquisition), these are extremely challenging tasks in this context, especially if the fusion is performed in a distributed manner. Our premise for the ISR SoS design and deployment is that the system is not designed as a complete system, where the capabilities of individual data providers are considered and the interaction paths, including communication channel capabilities, are specified at design time. Instead, we assume a loosely coupled SoS, where the data needs for a specific fusion task are described at a high level at design time and data providers (i.e., sensor systems) required for a specific fusion task are discovered dynamically at run time, the selection criteria for the data providers being the type and properties of data that can be provided by the specific data provider. The paper describes some of the aspects of a distributed ISR SoS design and implementation, bringing examples on both architectural design as well as on algorithm implementations.

  17. Task Release Control for Decision Making Queues

    CERN Document Server

    Srivastava, Vaibhav; Bullo, Francesco; Langbort, Cédric

    2010-01-01

    We consider the optimal duration allocation in a decision making queue. Decision making tasks arrive at a given rate to a human operator. The correctness of the decision made by human evolves as a sigmoidal function of the duration allocated to the task. Each task in the queue loses its value continuously. We elucidate on this trade-off and determine optimal policies for the human operator. We show the optimal policy requires the human to drop some tasks. We present a receding horizon optimization strategy, and compare it with the greedy policy.

  18. Analysis of Task-based Syllabus

    Institute of Scientific and Technical Information of China (English)

    马进胜

    2011-01-01

    Task-based language teaching is very popular in the modem English teaching.It is based on the Task-based Syllabus.Taskbased Syllabus focuses on the learners' communicative competence,which stresses learning by doing.From the theoretical assumption and definitions of the task,the paper analysizes the components of the task,then points out the merits and demerits of the syllabus.By this means the paper may give some tips to teachers and students when they use the tsk-based language teaching.

  19. Task oriented evaluation system for maintenance robots

    International Nuclear Information System (INIS)

    The adaptability evaluation of maintenance robots to autonomous plants has been discussed. In this paper, a new concept of autonomous plant with maintenance robots are introduced, and a framework of autonomous maintenance system is proposed. Then, task-oriented evaluation of robot arms is discussed for evaluating their adaptability to maintenance tasks, and a new criterion called operability is proposed for adaptability evaluation. The task-oriented evaluation system is implemented and applied to structural design of robot arms. Using genetic algorithm, an optimal structure adaptable to a pump disassembly task is obtained. (author)

  20. Guessing versus Choosing an Upcoming Task.

    Science.gov (United States)

    Kleinsorge, Thomas; Scheil, Juliane

    2016-01-01

    We compared the effects of guessing vs. choosing an upcoming task. In a task-switching paradigm with four tasks, two groups of participants were asked to either guess or choose which task will be presented next under otherwise identical conditions. The upcoming task corresponded to participants' guesses or choices in 75 % of the trials. However, only participants in the Choosing condition were correctly informed about this, whereas participants in the Guessing condition were told that tasks were determined at random. In the Guessing condition, we replicated previous findings of a pronounced reduction of switch costs in case of incorrect guesses. This switch cost reduction was considerably less pronounced with denied choices in the Choosing condition. We suggest that in the Choosing condition, the signaling of prediction errors associated with denied choices is attenuated because a certain proportion of denied choices is consistent with the overall representation of the situation as conveyed by task instructions. In the Guessing condition, in contrast, the mismatch of guessed and actual task is resolved solely on the level of individual trials by strengthening the representation of the actual task. PMID:27047423

  1. TASK 2: QUENCH ZONE SIMULATION

    Energy Technology Data Exchange (ETDEWEB)

    Fusselman, Steve

    2015-09-30

    Aerojet Rocketdyne (AR) has developed an innovative gasifier concept incorporating advanced technologies in ultra-dense phase dry feed system, rapid mix injector, and advanced component cooling to significantly improve gasifier performance, life, and cost compared to commercially available state-of-the-art systems. A key feature of the AR gasifier design is the transition from the gasifier outlet into the quench zone, where the raw syngas is cooled to ~ 400°C by injection and vaporization of atomized water. Earlier pilot plant testing revealed a propensity for the original gasifier outlet design to accumulate slag in the outlet, leading to erratic syngas flow from the outlet. Subsequent design modifications successfully resolved this issue in the pilot plant gasifier. In order to gain greater insight into the physical phenomena occurring within this zone, AR developed a cold flow simulation apparatus with Coanda Research & Development with a high degree of similitude to hot fire conditions with the pilot scale gasifier design, and capable of accommodating a scaled-down quench zone for a demonstration-scale gasifier. The objective of this task was to validate similitude of the cold flow simulation model by comparison of pilot-scale outlet design performance, and to assess demonstration scale gasifier design feasibility from testing of a scaled-down outlet design. Test results did exhibit a strong correspondence with the two pilot scale outlet designs, indicating credible similitude for the cold flow simulation device. Testing of the scaled-down outlet revealed important considerations in the design and operation of the demonstration scale gasifier, in particular pertaining to the relative momentum between the downcoming raw syngas and the sprayed quench water and associated impacts on flow patterns within the quench zone. This report describes key findings from the test program, including assessment of pilot plant configuration simulations relative to actual

  2. Drug and alcohol task force

    International Nuclear Information System (INIS)

    Worker absenteeism due to substance abuse costs the Alberta economy approximately $720 million a year. It is estimated that 20 per cent of all drivers in fatal crashes were using alcohol, and the use of cannabis and cocaine in Alberta has more than doubled over the last 15 years. In addition, 1 in 10 Alberta workers have reported using alcohol while at work and 4 per cent have reported using alcohol 4 hours prior to coming to work during the previous 12 months. In an effort to ensure appropriate health and safety for workers in the Canadian petroleum industry, 6 trade associations in the sector have joined together as the Enform Alcohol and Drug Initiative and are now working to develop a common approach to drug and alcohol guidelines and workplace rules. The task group will determine if existing policies and guidelines are sufficient to ensure a safe workplace and will consider standardizing the testing, application and rehabilitation of workers with respect to the use of drugs and alcohol. In the past, disciplinary actions have often been reversed because employers have not been consistent or did not follow established alcohol and drug policies or test to specific standards. Various work rules for inappropriate alcohol and drug use were reviewed, as well as education and communication strategies regarding policy content. Standards for testing criteria were discussed, as well as issues concerning duty-to-accommodate circumstances. An excerpt of concentration standards was presented. It was concluded that a matrix for companies to assess and determine safety sensitive positions is needed. refs., tabs., figs

  3. Drug and alcohol task force

    Energy Technology Data Exchange (ETDEWEB)

    Gordey, T. [ConocoPhillips Canada Resources Corp., Calgary, AB (Canada); Sunstrum, M. [Enform, Calgary, AB (Canada)

    2006-07-01

    Worker absenteeism due to substance abuse costs the Alberta economy approximately $720 million a year. It is estimated that 20 per cent of all drivers in fatal crashes were using alcohol, and the use of cannabis and cocaine in Alberta has more than doubled over the last 15 years. In addition, 1 in 10 Alberta workers have reported using alcohol while at work and 4 per cent have reported using alcohol 4 hours prior to coming to work during the previous 12 months. In an effort to ensure appropriate health and safety for workers in the Canadian petroleum industry, 6 trade associations in the sector have joined together as the Enform Alcohol and Drug Initiative and are now working to develop a common approach to drug and alcohol guidelines and workplace rules. The task group will determine if existing policies and guidelines are sufficient to ensure a safe workplace and will consider standardizing the testing, application and rehabilitation of workers with respect to the use of drugs and alcohol. In the past, disciplinary actions have often been reversed because employers have not been consistent or did not follow established alcohol and drug policies or test to specific standards. Various work rules for inappropriate alcohol and drug use were reviewed, as well as education and communication strategies regarding policy content. Standards for testing criteria were discussed, as well as issues concerning duty-to-accommodate circumstances. An excerpt of concentration standards was presented. It was concluded that a matrix for companies to assess and determine safety sensitive positions is needed. refs., tabs., figs.

  4. Synchronizing Parallel Tasks Using STM

    Directory of Open Access Journals (Sweden)

    Ryan Saptarshi Ray

    2015-03-01

    Full Text Available The past few years have marked the start of a historic transition from sequential to parallel computation. The necessity to write parallel programs is increasing as systems are getting more complex while processor speed increases are slowing down. Current parallel programming uses low-level programming constructs like threads and explicit synchronization using locks to coordinate thread execution. Parallel programs written with these constructs are difficult to design, program and debug. Also locks have many drawbacks which make them a suboptimal solution. One such drawback is that locks should be only used to enclose the critical section of the parallel-processing code. If locks are used to enclose the entire code then the performance of the code drastically decreases. Software Transactional Memory (STM is a promising new approach to programming shared-memory parallel processors. It is a concurrency control mechanism that is widely considered to be easier to use by programmers than locking. It allows portions of a program to execute in isolation, without regard to other, concurrently executing tasks. A programmer can reason about the correctness of code within a transaction and need not worry about complex interactions with other, concurrently executing parts of the program. If STM is used to enclose the entire code then the performance of the code is the same as that of the code in which STM is used to enclose the critical section only and is far better than code in which locks have been used to enclose the entire code. So STM is easier to use than locks as critical section does not need to be identified in case of STM. This paper shows the concept of writing code using Software Transactional Memory (STM and the performance comparison of codes using locks with those using STM. It also shows why the use of STM in parallel-processing code is better than the use of locks.

  5. Different neuroplasticity for task targets and distractors.

    Directory of Open Access Journals (Sweden)

    Elsie Y Spingath

    Full Text Available Adult learning-induced sensory cortex plasticity results in enhanced action potential rates in neurons that have the most relevant information for the task, or those that respond strongly to one sensory stimulus but weakly to its comparison stimulus. Current theories suggest this plasticity is caused when target stimulus evoked activity is enhanced by reward signals from neuromodulatory nuclei. Prior work has found evidence suggestive of nonselective enhancement of neural responses, and suppression of responses to task distractors, but the differences in these effects between detection and discrimination have not been directly tested. Using cortical implants, we defined physiological responses in macaque somatosensory cortex during serial, matched, detection and discrimination tasks. Nonselective increases in neural responsiveness were observed during detection learning. Suppression of responses to task distractors was observed during discrimination learning, and this suppression was specific to cortical locations that sampled responses to the task distractor before learning. Changes in receptive field size were measured as the area of skin that had a significant response to a constant magnitude stimulus, and these areal changes paralleled changes in responsiveness. From before detection learning until after discrimination learning, the enduring changes were selective suppression of cortical locations responsive to task distractors, and nonselective enhancement of responsiveness at cortical locations selective for target and control skin sites. A comparison of observations in prior studies with the observed plasticity effects suggests that the non-selective response enhancement and selective suppression suffice to explain known plasticity phenomena in simple spatial tasks. This work suggests that differential responsiveness to task targets and distractors in primary sensory cortex for a simple spatial detection and discrimination task arise from

  6. Evaluation of 2 cognitive abilities tests in a dual-task environment

    Science.gov (United States)

    Vidulich, M. A.; Tsang, P. S.

    1986-01-01

    Most real world operators are required to perform multiple tasks simultaneously. In some cases, such as flying a high performance aircraft or trouble shooting a failing nuclear power plant, the operator's ability to time share or process in parallel" can be driven to extremes. This has created interest in selection tests of cognitive abilities. Two tests that have been suggested are the Dichotic Listening Task and the Cognitive Failures Questionnaire. Correlations between these test results and time sharing performance were obtained and the validity of these tests were examined. The primary task was a tracking task with dynamically varying bandwidth. This was performed either alone or concurrently with either another tracking task or a spatial transformation task. The results were: (1) An unexpected negative correlation was detected between the two tests; (2) The lack of correlation between either test and task performance made the predictive utility of the tests scores appear questionable; (3) Pilots made more errors on the Dichotic Listening Task than college students.

  7. Task based synthesis of serial manipulators

    Directory of Open Access Journals (Sweden)

    Sarosh Patel

    2015-05-01

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

  8. SemEval-2016 task 10

    DEFF Research Database (Denmark)

    Schneider, Nathan; Hovy, Dirk; Johannsen, Anders Trærup;

    2016-01-01

    This task combines the labeling of multiword expressions and supersenses (coarse-grained classes) in an explicit, yet broad-coverage paradigm for lexical semantics. Nine systems participated; the best scored 57.7% F1 in a multi-domain evaluation setting, indicating that the task remains largely u...

  9. Machine Tool Series. Duty Task List.

    Science.gov (United States)

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This task list is intended for use in planning and/or evaluating a competency-based course to prepare machine tool, drill press, grinding machine, lathe, mill, and/or power saw operators. The listing is divided into six sections, with each one outlining the tasks required to perform the duties that have been identified for the given occupation.…

  10. Brief Family Therapy: A Metaphorical Task.

    Science.gov (United States)

    de Shazer, Steve

    1980-01-01

    Presents a therapeutic procedure designed to prescribe the family's troublesome behavior pattern. A complement precedes delivering a task assignment. The metaphorical task redefines the serious complaint pattern into only one of the many options a family has for dealing with each other. A case study is presented. (Author/BEF)

  11. Students' Views of Example Generation Tasks

    Science.gov (United States)

    Breen, Sinead; O'Shea, Ann; Pfeiffer, Kirsten

    2016-01-01

    We report here on students' views of example generation tasks assigned to them in two first year undergraduate Calculus courses. The design and use of such tasks was undertaken as part of a project which aimed to afford students opportunities to develop their thinking skills and their conceptual understanding. In interviews with 10 students, we…

  12. Workplace for analysis of task performance

    NARCIS (Netherlands)

    Bos, J; Mulder, LJM; van Ouwerkerk, RJ; Maarse, FJ; Akkerman, AE; Brand, AN; Mulder, LJM

    2003-01-01

    In current research on mental workload and task performance a large gap exists between laboratory based studies and research projects in real life working practice. Tasks conducted within a laboratory environment often lack a strong resemblance with real life working situations. This paper presents

  13. Shaping Academic Task Engagement with Percentile Schedules

    Science.gov (United States)

    Athens, Elizabeth S.; Vollmer, Timothy R.; St. Peter Pipkin, Claire C.

    2007-01-01

    The purpose of this study was to examine the use of percentile schedules as a method of quantifying the shaping procedure in an educational setting. We compared duration of task engagement during baseline measurements for 4 students to duration of task engagement during a percentile schedule. As a secondary purpose, we examined the influence on…

  14. A Hybrid Task Scheduling Algorithm in Grid

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan-mei; CAO Huai-hu; YU Zhen-wei

    2006-01-01

    Task scheduling in Grid has been proved to be NP- complete problem. In this paper, to solve this problem, a Hybrid Task Scheduling Algorithm in Grid (HTS) has been presented, which joint the advantages of Ant Colony and Genetic Algorithm.Compared with the related work, the result shows that the HTS algorithm significantly surpasses the previous approaches in schedule length ratio and speedup.

  15. Studying different tasks of implicit learning across multiple test sessions conducted on the web

    Directory of Open Access Journals (Sweden)

    Werner eSævland

    2016-06-01

    Full Text Available Implicit learning is usually studied through individual performance on a single task, with the most common tasks being Serial Reaction Time task (SRT; Nissen and Bullemer, 1987, Dynamic System Control task (DSC; (Berry and Broadbent, 1984 and artificial Grammar Learning task (AGL; (Reber, 1967. Few attempts have been made to compare performance across different implicit learning tasks within the same experiment. The current experiment was designed study the relationship between performance on the DSC Sugar factory task (Berry and Broadbent, 1984 and the Alternating Serial Reaction Time task (ASRT; (Howard and Howard, 1997. We also addressed another limitation to traditional implicit learning experiments, namely that implicit learning is usually studied in laboratory settings over a restricted time span lasting for less than an hour (Berry and Broadbent, 1984; Nissen and Bullemer, 1987; Reber, 1967. In everyday situations, implicit learning is assumed to involve a gradual accumulation of knowledge across several learning episodes over a larger time span (Norman and Price, 2012. One way to increase the ecological validity of implicit learning experiments could be to present the learning material repeatedly across shorter experimental sessions (Howard and Howard, 1997; Cleeremans and McClelland, 1991. This can most easily be done by using a web-based setup that participants can access from home. We therefore created an online web-based system for measuring implicit learning that could be administered in either single or multiple sessions. Participants (n = 66 were assigned to either a single-session or a multi-session condition. Learning and the degree of conscious awareness of the learned regularities was compared across condition (single vs. multiple sessions and tasks (DSC vs. ASRT. Results showed that learning on the two tasks was not related. However, participants in the multiple sessions condition did show greater improvements in reaction

  16. Task-specific modulation of effective connectivity during two simple unimanual motor tasks: A 122-channel EEG study

    DEFF Research Database (Denmark)

    Herz, Damian M.; Christensen, Mark S.; Reck, Christiane;

    2012-01-01

    -related modulations of inter-regional coupling within a core motor network comprising the left primary motor cortex (M1), lateral premotor cortex (lPM) and supplementary motor area (SMA) were then modeled using dynamic causal modeling (DCM). A network model postulating coupling both within and across frequencies best......) and between the θ- (4–7 Hz) and the γ-band. This coupling pattern was mainly expressed in connections from lPM to SMA and from lPM to M1. We infer that human manual motor control involves task-specific modulation of inter-regional oscillatory coupling both within and across distinct frequency bands...

  17. Robot Task Commander with Extensible Programming Environment

    Science.gov (United States)

    Hart, Stephen W (Inventor); Yamokoski, John D. (Inventor); Wightman, Brian J (Inventor); Dinh, Duy Paul (Inventor); Gooding, Dustin R (Inventor)

    2014-01-01

    A system for developing distributed robot application-level software includes a robot having an associated control module which controls motion of the robot in response to a commanded task, and a robot task commander (RTC) in networked communication with the control module over a network transport layer (NTL). The RTC includes a script engine(s) and a GUI, with a processor and a centralized library of library blocks constructed from an interpretive computer programming code and having input and output connections. The GUI provides access to a Visual Programming Language (VPL) environment and a text editor. In executing a method, the VPL is opened, a task for the robot is built from the code library blocks, and data is assigned to input and output connections identifying input and output data for each block. A task sequence(s) is sent to the control module(s) over the NTL to command execution of the task.

  18. Net-Based Task Management System

    Institute of Scientific and Technical Information of China (English)

    LIQiang; TIANLing; TONGBing-shu

    2004-01-01

    In net-based collaborative design environment, design resources become more and more varied and complex. Besides common information management systems, design resources can be organized in connection with design activities. A set of activities and resources linked by logic relations can form a task. A task has at least one objective and can be broken down into smaller ones. So a design project can be separated into many subtasks forming a hierarchical structure. Task Management System (TMS) is designed to break down these tasks and assign certain resources to its related task nodes. As a result of decomposition, all design resources and activities could be managed via this system. Based on this idea, we realized a TMS which manages collaborative resources in web environment.

  19. Task-specific dystonia: pathophysiology and management.

    Science.gov (United States)

    Sadnicka, Anna; Kassavetis, Panagiotis; Pareés, Isabel; Meppelink, Anne Marthe; Butler, Katherine; Edwards, Mark

    2016-09-01

    Task-specific dystonia is a form of isolated focal dystonia with the peculiarity of being displayed only during performance of a specific skilled motor task. This distinctive feature makes task-specific dystonia a particularly mysterious and fascinating neurological condition. In this review, we cover phenomenology and its increasingly broad-spectrum risk factors for the disease, critically review pathophysiological theories and evaluate current therapeutic options. We conclude by highlighting the unique features of task-specific dystonia within the wider concept of dystonia. We emphasise the central contribution of environmental risk factors, and propose a model by which these triggers may impact on the motor control of skilled movement. By viewing task-specific dystonia through this new lens which considers the disorder a modifiable disorder of motor control, we are optimistic that research will yield novel therapeutic avenues for this highly motivated group of patients.

  20. Learning to Model Task-Oriented Attention

    Directory of Open Access Journals (Sweden)

    Xiaochun Zou

    2016-01-01

    Full Text Available For many applications in graphics, design, and human computer interaction, it is essential to understand where humans look in a scene with a particular task. Models of saliency can be used to predict fixation locations, but a large body of previous saliency models focused on free-viewing task. They are based on bottom-up computation that does not consider task-oriented image semantics and often does not match actual eye movements. To address this problem, we collected eye tracking data of 11 subjects when they performed some particular search task in 1307 images and annotation data of 2,511 segmented objects with fine contours and 8 semantic attributes. Using this database as training and testing examples, we learn a model of saliency based on bottom-up image features and target position feature. Experimental results demonstrate the importance of the target information in the prediction of task-oriented visual attention.

  1. Task mapping for non-contiguous allocations.

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Vitus Joseph; Bunde, David P.; Ebbers, Johnathan; Price, Nicholas W.; Swank, Matthew.; Feer, Stefan P.; Rhodes, Zachary D.

    2013-02-01

    This paper examines task mapping algorithms for non-contiguously allocated parallel jobs. Several studies have shown that task placement affects job running time for both contiguously and non-contiguously allocated jobs. Traditionally, work on task mapping either uses a very general model where the job has an arbitrary communication pattern or assumes that jobs are allocated contiguously, making them completely isolated from each other. A middle ground between these two cases is the mapping problem for non-contiguous jobs having a specific communication pattern. We propose several task mapping algorithms for jobs with a stencil communication pattern and evaluate them using experiments and simulations. Our strategies improve the running time of a MiniApp by as much as 30% over a baseline strategy. Furthermore, this improvement increases markedly with the job size, demonstrating the importance of task mapping as systems grow toward exascale.

  2. Task-specific dystonia: pathophysiology and management.

    Science.gov (United States)

    Sadnicka, Anna; Kassavetis, Panagiotis; Pareés, Isabel; Meppelink, Anne Marthe; Butler, Katherine; Edwards, Mark

    2016-09-01

    Task-specific dystonia is a form of isolated focal dystonia with the peculiarity of being displayed only during performance of a specific skilled motor task. This distinctive feature makes task-specific dystonia a particularly mysterious and fascinating neurological condition. In this review, we cover phenomenology and its increasingly broad-spectrum risk factors for the disease, critically review pathophysiological theories and evaluate current therapeutic options. We conclude by highlighting the unique features of task-specific dystonia within the wider concept of dystonia. We emphasise the central contribution of environmental risk factors, and propose a model by which these triggers may impact on the motor control of skilled movement. By viewing task-specific dystonia through this new lens which considers the disorder a modifiable disorder of motor control, we are optimistic that research will yield novel therapeutic avenues for this highly motivated group of patients. PMID:26818730

  3. Learning to Model Task-Oriented Attention.

    Science.gov (United States)

    Zou, Xiaochun; Zhao, Xinbo; Wang, Jian; Yang, Yongjia

    2016-01-01

    For many applications in graphics, design, and human computer interaction, it is essential to understand where humans look in a scene with a particular task. Models of saliency can be used to predict fixation locations, but a large body of previous saliency models focused on free-viewing task. They are based on bottom-up computation that does not consider task-oriented image semantics and often does not match actual eye movements. To address this problem, we collected eye tracking data of 11 subjects when they performed some particular search task in 1307 images and annotation data of 2,511 segmented objects with fine contours and 8 semantic attributes. Using this database as training and testing examples, we learn a model of saliency based on bottom-up image features and target position feature. Experimental results demonstrate the importance of the target information in the prediction of task-oriented visual attention. PMID:27247561

  4. Trait Mindfulness and Cognitive Task Performance

    Directory of Open Access Journals (Sweden)

    Emalee J. W. Quickel

    2014-11-01

    Full Text Available Mindfulness meditation (MM training has been shown to have positive effects on working memory and focused attention tasks. Clarifying the construct of mindfulness is important so that mindfulness can be studied effectively in individual differences and cognition research. The current study tested whether trait mindfulness alone explains any of the variability on task performance. Five commonly used mindfulness scales, as well as six standardized and experimental attention and working memory tasks were administered to 164 participants with no meditation experience. Confirmatory factor analysis found that the common variance denoted by measures of trait mindfulness is unrelated to the common variance among tasks requiring focused attention. These results indicate that mindfulness scales may not be capturing the attentional aspects of mindfulness. Individuals who score high on mindfulness scales do not perform better on focused attention tasks than those who score lower on mindfulness scales. These results have implications for defining and operationalizing mindfulness.

  5. Error Sonification of a Complex Motor Task

    Directory of Open Access Journals (Sweden)

    Riener Robert

    2011-12-01

    Full Text Available Visual information is mainly used to master complex motor tasks. Thus, additional information providing augmented feedback should be displayed in other modalities than vision, e.g. hearing. The present work evaluated the potential of error sonification to enhance learning of a rowing-type motor task. In contrast to a control group receiving self-controlled terminal feedback, the experimental group could not significantly reduce spatial errors. Thus, motor learning was not enhanced by error sonification, although during the training the participant could benefit from it. It seems that the motor task was too slow, resulting in immediate corrections of the movement rather than in an internal representation of the general characteristics of the motor task. Therefore, further studies should elaborate the impact of error sonification when general characteristics of the motor tasks are already known.

  6. Analysis of the Discontinuities in Prioritized Tasks-Space Control Under Discrete Task Scheduling Operations

    OpenAIRE

    Keith, François; Wieber, Pierre-Brice; Mansard, Nicolas; Kheddar, Abderrahmane

    2011-01-01

    International audience This paper examines the control continuity in hierarchical task-space controllers. While the continuity is ensured for any a priori fixed number of tasks -even in ill-conditioned configurations-, the control resulting from a hierarchical stack-of-task computation may not be continuous under some discrete events. In particular, we study how the continuity of the stack-of-task control computation is affected under discreet scheduling operations such as on-the-fly prior...

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

    Science.gov (United States)

    Kim, Youjin; Taguchi, Naoko

    2015-01-01

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

  8. Cognitive Complexity of Mathematics Instructional Tasks in a Taiwanese Classroom: An Examination of Task Sources

    Science.gov (United States)

    Hsu, Hui-Yu; Silver, Edward A.

    2014-01-01

    We examined geometric calculation with number tasks used within a unit of geometry instruction in a Taiwanese classroom, identifying the source of each task used in classroom instruction and analyzing the cognitive complexity of each task with respect to 2 distinct features: diagram complexity and problem-solving complexity. We found that…

  9. Hand Interface in Traditional Modeling and Animation Tasks

    Institute of Scientific and Technical Information of China (English)

    孙汉秋

    1996-01-01

    3-D task space in modeling and animation is usually reduced to the separate control dimensions supported by conventional interactive devices.This limitation maps only partial view of the problem to the device space at a time,and results in tedious and unnatural interface of control.This paper uses the DataGlove interface for modeling and animating scene behaviors.The modeling interface selects,scales,rotates,translates,copies and deletes the instances of the primitives.These basic modeling processes are directly performed in the task space,using hand shapes and motions.Hand shapes are recognized as discrete states that trigger the commands,and hand motion are mapped to the movement of a selected instance.The interactions through hand interface place the user as a participant in the process of behavior simulation.Both event triggering and role switching of hand are experimented in simulation.The event mode of hand triggers control signals or commands through a menu interface.The object mode of hand simulates itself as an object whose appearance or motion influences the motions of other objects in scene.The involvement of hand creates a diversity of dynamic situations for testing variable scene behaviors.Our experiments have shown the potential use of this interface directly in the 3-D modeling and animation task space.

  10. Stochastic model predicts evolving preferences in the Iowa gambling task

    Science.gov (United States)

    Fuentes, Miguel A.; Lavín, Claudio; Contreras-Huerta, L. Sebastián; Miguel, Hernan; Rosales Jubal, Eduardo

    2014-01-01

    Learning under uncertainty is a common task that people face in their daily life. This process relies on the cognitive ability to adjust behavior to environmental demands. Although the biological underpinnings of those cognitive processes have been extensively studied, there has been little work in formal models seeking to capture the fundamental dynamic of learning under uncertainty. In the present work, we aimed to understand the basic cognitive mechanisms of outcome processing involved in decisions under uncertainty and to evaluate the relevance of previous experiences in enhancing learning processes within such uncertain context. We propose a formal model that emulates the behavior of people playing a well established paradigm (Iowa Gambling Task - IGT) and compare its outcome with a behavioral experiment. We further explored whether it was possible to emulate maladaptive behavior observed in clinical samples by modifying the model parameter which controls the update of expected outcomes distributions. Results showed that the performance of the model resembles the observed participant performance as well as IGT performance by healthy subjects described in the literature. Interestingly, the model converges faster than some subjects on the decks with higher net expected outcome. Furthermore, the modified version of the model replicated the trend observed in clinical samples performing the task. We argue that the basic cognitive component underlying learning under uncertainty can be represented as a differential equation that considers the outcomes of previous decisions for guiding the agent to an adaptive strategy. PMID:25566043

  11. Robust visual tracking via multi-task sparse learning

    KAUST Repository

    Zhang, Tianzhu

    2012-06-01

    In this paper, we formulate object tracking in a particle filter framework as a multi-task sparse learning problem, which we denote as Multi-Task Tracking (MTT). Since we model particles as linear combinations of dictionary templates that are updated dynamically, learning the representation of each particle is considered a single task in MTT. By employing popular sparsity-inducing p, q mixed norms (p D; 1), we regularize the representation problem to enforce joint sparsity and learn the particle representations together. As compared to previous methods that handle particles independently, our results demonstrate that mining the interdependencies between particles improves tracking performance and overall computational complexity. Interestingly, we show that the popular L 1 tracker [15] is a special case of our MTT formulation (denoted as the L 11 tracker) when p q 1. The learning problem can be efficiently solved using an Accelerated Proximal Gradient (APG) method that yields a sequence of closed form updates. As such, MTT is computationally attractive. We test our proposed approach on challenging sequences involving heavy occlusion, drastic illumination changes, and large pose variations. Experimental results show that MTT methods consistently outperform state-of-the-art trackers. © 2012 IEEE.

  12. Developmental changes in using verbal self-cueing in task-switching situations: The impact of task practice and task-sequencing demands

    Directory of Open Access Journals (Sweden)

    Jutta eKray

    2013-12-01

    Full Text Available In this study we examined whether developmental changes in using verbal self-cueing for task-goal maintenance are dependent on the amount of task practice and task-sequencing demands. To measure task-goal maintenance we applied a switching paradigm in which children either performed only task A or B in single-task blocks or switched between them on every second trial in mixed-task blocks. Task-goal maintenance was determined by comparing the performance between both blocks (mixing costs. The influence of verbal self-cueing was measured by instructing children to either name the next task aloud or not to verbalize during task preparation. Task-sequencing demands were varied between groups whereas one group received spatial task cues to support keeping track of the task sequence, while the other group did not. We also varied by the amount of prior practice in task switching while one group of participants practiced task switching first, before performing the task naming in addition, and the other group did it vice versa. Results of our study investigating younger (8-10 years and older children (11-13 years revealed no age differences in beneficial effects of verbal self-cueing. In line with previous findings, children showed reduced mixing costs under task-naming instructions and under conditions of low task-sequence demands (with the presence of spatial task cues. Our results also indicated that these benefits were only obtained for those groups of children that first received practice in task switching alone with no additional verbalization instruction. These findings suggest that internal task-cueing strategies can be efficiently used in children but only if they received prior practice in the underlying task so that demands on keeping and coordinating various instructions are reduced. Moreover, children benefitted from spatial task cues for better task-goal maintenance only if no verbal task-cueing strategy was introduced first.

  13. A Scheduling Algorithm for Cloud Computing System Based on the Driver of Dynamic Essential Path.

    Science.gov (United States)

    Xie, Zhiqiang; Shao, Xia; Xin, Yu

    2016-01-01

    To solve the problem of task scheduling in the cloud computing system, this paper proposes a scheduling algorithm for cloud computing based on the driver of dynamic essential path (DDEP). This algorithm applies a predecessor-task layer priority strategy to solve the problem of constraint relations among task nodes. The strategy assigns different priority values to every task node based on the scheduling order of task node as affected by the constraint relations among task nodes, and the task node list is generated by the different priority value. To address the scheduling order problem in which task nodes have the same priority value, the dynamic essential long path strategy is proposed. This strategy computes the dynamic essential path of the pre-scheduling task nodes based on the actual computation cost and communication cost of task node in the scheduling process. The task node that has the longest dynamic essential path is scheduled first as the completion time of task graph is indirectly influenced by the finishing time of task nodes in the longest dynamic essential path. Finally, we demonstrate the proposed algorithm via simulation experiments using Matlab tools. The experimental results indicate that the proposed algorithm can effectively reduce the task Makespan in most cases and meet a high quality performance objective.

  14. A Scheduling Algorithm for Cloud Computing System Based on the Driver of Dynamic Essential Path.

    Science.gov (United States)

    Xie, Zhiqiang; Shao, Xia; Xin, Yu

    2016-01-01

    To solve the problem of task scheduling in the cloud computing system, this paper proposes a scheduling algorithm for cloud computing based on the driver of dynamic essential path (DDEP). This algorithm applies a predecessor-task layer priority strategy to solve the problem of constraint relations among task nodes. The strategy assigns different priority values to every task node based on the scheduling order of task node as affected by the constraint relations among task nodes, and the task node list is generated by the different priority value. To address the scheduling order problem in which task nodes have the same priority value, the dynamic essential long path strategy is proposed. This strategy computes the dynamic essential path of the pre-scheduling task nodes based on the actual computation cost and communication cost of task node in the scheduling process. The task node that has the longest dynamic essential path is scheduled first as the completion time of task graph is indirectly influenced by the finishing time of task nodes in the longest dynamic essential path. Finally, we demonstrate the proposed algorithm via simulation experiments using Matlab tools. The experimental results indicate that the proposed algorithm can effectively reduce the task Makespan in most cases and meet a high quality performance objective. PMID:27490901

  15. A Scheduling Algorithm for Cloud Computing System Based on the Driver of Dynamic Essential Path

    Science.gov (United States)

    Xie, Zhiqiang; Shao, Xia; Xin, Yu

    2016-01-01

    To solve the problem of task scheduling in the cloud computing system, this paper proposes a scheduling algorithm for cloud computing based on the driver of dynamic essential path (DDEP). This algorithm applies a predecessor-task layer priority strategy to solve the problem of constraint relations among task nodes. The strategy assigns different priority values to every task node based on the scheduling order of task node as affected by the constraint relations among task nodes, and the task node list is generated by the different priority value. To address the scheduling order problem in which task nodes have the same priority value, the dynamic essential long path strategy is proposed. This strategy computes the dynamic essential path of the pre-scheduling task nodes based on the actual computation cost and communication cost of task node in the scheduling process. The task node that has the longest dynamic essential path is scheduled first as the completion time of task graph is indirectly influenced by the finishing time of task nodes in the longest dynamic essential path. Finally, we demonstrate the proposed algorithm via simulation experiments using Matlab tools. The experimental results indicate that the proposed algorithm can effectively reduce the task Makespan in most cases and meet a high quality performance objective. PMID:27490901

  16. Survival Processing and the Stroop Task

    Directory of Open Access Journals (Sweden)

    Stephanie A. Kazanas

    2015-11-01

    Full Text Available This study was designed to investigate the impact of survival processing with a novel task for this paradigm: the Stroop color-naming task. As the literature is mixed with regard to task generalizability, with survival processing promoting better memory for words, but not better memory for faces or paired associates, these types of task investigations are important to a growing field of research. Using the Stroop task provides a unique contribution, as identifying items by color is an important evolutionary adaptation and not specific to humans as is the case with word recall. Our results indicate that survival processing, with its accompanying survival-relevance rating task, remains the best mnemonic strategy for word memory. However, our results also indicate that presenting the survival passage does not motivate better color-naming performance than color-naming alone. In addition, survival processing led to a larger amount of Stroop interference, though not significantly larger than the other conditions. Together, these findings suggest that considering one’s survival when performing memory and attention-based tasks does not enhance cognitive performance generally, although greater allocation of attentional resources to color-incongruent concrete objects could be considered adaptive. These findings support the notion that engaging in deeper processing via survival-relevance ratings may preserve these words across a variety of experimental manipulations.

  17. Dual Task Impairments in Vascular Dementia

    Directory of Open Access Journals (Sweden)

    Kate Inasaridze

    2010-01-01

    Full Text Available Several studies have shown that people with Alzheimer's disease (AD demonstrate difficulties in doing two things at once or 'dual-tasking' and that this dual task impairment is insensitive to normal ageing, chronic depression or prodromal conditions like Mild Cognitive Impairment. It is not known, however, if this impairment is specific to AD, or also present in other dementias, such as vascular dementia (VaD. In this study 15 people with VaD, 25 healthy age-matched and 25 healthy young controls were assessed using a paper and pencil dual tasking paradigm and several measures of working and episodic memory. Age had no effect on dual task performance, but the VaD patients demonstrated a significant impairment in dual tasking ability. Performance on the memory measures was instead affected by age with a further deterioration in the VaD patients. Both dual tasking and memory ability were significantly correlated with disease severity, as assessed by the MMSE. These results indicate that performance on the dual task could be a specific indicator of pathological ageing.

  18. Overview of the ID, EPI and REL tasks of BioNLP Shared Task 2011

    Directory of Open Access Journals (Sweden)

    Pyysalo Sampo

    2012-06-01

    Full Text Available Abstract We present the preparation, resources, results and analysis of three tasks of the BioNLP Shared Task 2011: the main tasks on Infectious Diseases (ID and Epigenetics and Post-translational Modifications (EPI, and the supporting task on Entity Relations (REL. The two main tasks represent extensions of the event extraction model introduced in the BioNLP Shared Task 2009 (ST'09 to two new areas of biomedical scientific literature, each motivated by the needs of specific biocuration tasks. The ID task concerns the molecular mechanisms of infection, virulence and resistance, focusing in particular on the functions of a class of signaling systems that are ubiquitous in bacteria. The EPI task is dedicated to the extraction of statements regarding chemical modifications of DNA and proteins, with particular emphasis on changes relating to the epigenetic control of gene expression. By contrast to these two application-oriented main tasks, the REL task seeks to support extraction in general by separating challenges relating to part-of relations into a subproblem that can be addressed by independent systems. Seven groups participated in each of the two main tasks and four groups in the supporting task. The participating systems indicated advances in the capability of event extraction methods and demonstrated generalization in many aspects: from abstracts to full texts, from previously considered subdomains to new ones, and from the ST'09 extraction targets to other entities and events. The highest performance achieved in the supporting task REL, 58% F-score, is broadly comparable with levels reported for other relation extraction tasks. For the ID task, the highest-performing system achieved 56% F-score, comparable to the state-of-the-art performance at the established ST'09 task. In the EPI task, the best result was 53% F-score for the full set of extraction targets and 69% F-score for a reduced set of core extraction targets, approaching a level

  19. Stability control during the performance of a simultaneous obstacle avoidance and auditory Stroop task.

    Science.gov (United States)

    Worden, Timothy A; Vallis, Lori Ann

    2016-02-01

    Navigation through complex environments requires a greater degree of control and attentional resources from the central nervous system to ensure postural stability and efficient goal completion as compared to quiet standing or unobstructed walking. Furthermore, when a cognitive task is also performed in a dual-task scenario, additional resources may be required. The purpose of the current study was to examine the effects of performing a concurrent cognitive (auditory Stroop task) and complex locomotor task (with a stationary or dynamic obstacle) on frontal plane stability control quantified using a margin of stability (MOS) measure. Fourteen healthy young adults performed 40 dual-task trials (randomized in a balanced design for auditory Stroop congruency and obstacle movement). Results indicated that frontal plane MOS was greatest for the obstacle crossing step and was greater for the dynamic obstacle as compared to the stationary obstacle. Conversely, frontal plane MOS was the smallest for the pre-crossing step, indicating that this point in the obstacle stepping strategy may be the least stable. No effect of cognitive task difficulty was observed for any of the experimental conditions, providing support for a 'posture-first' strategy. These findings suggest that an increase in stability is prioritized for the obstacle crossing step, potentially at the expense of reduced stability in the step immediately preceding the obstacle. These results have implications for better understanding how the CNS controls stability at different events during the obstacle crossing strategy in a complex environment. PMID:26487180

  20. Task Allocation and Path Planning for Collaborative Autonomous Underwater Vehicles Operating through an Underwater Acoustic Network

    Directory of Open Access Journals (Sweden)

    Yueyue Deng

    2013-01-01

    Full Text Available Dynamic and unstructured multiple cooperative autonomous underwater vehicle (AUV missions are highly complex operations, and task allocation and path planning are made significantly more challenging under realistic underwater acoustic communication constraints. This paper presents a solution for the task allocation and path planning for multiple AUVs under marginal acoustic communication conditions: a location-aided task allocation framework (LAAF algorithm for multitarget task assignment and the grid-based multiobjective optimal programming (GMOOP mathematical model for finding an optimal vehicle command decision given a set of objectives and constraints. Both the LAAF and GMOOP algorithms are well suited in poor acoustic network condition and dynamic environment. Our research is based on an existing mobile ad hoc network underwater acoustic simulator and blind flooding routing protocol. Simulation results demonstrate that the location-aided auction strategy performs significantly better than the well-accepted auction algorithm developed by Bertsekas in terms of task-allocation time and network bandwidth consumption. We also demonstrate that the GMOOP path-planning technique provides an efficient method for executing multiobjective tasks by cooperative agents with limited communication capabilities. This is in contrast to existing multiobjective action selection methods that are limited to networks where constant, reliable communication is assumed to be available.

  1. Fatigue effects on knee joint stability during two jump tasks in women.

    Science.gov (United States)

    Ortiz, Alexis; Olson, Sharon L; Etnyre, Bruce; Trudelle-Jackson, Elaine E; Bartlett, William; Venegas-Rios, Heidi L

    2010-04-01

    Dynamic knee joint stability may be affected by the onset of metabolic fatigue during sports participation that could increase the risk for knee injury. The purpose of this investigation was to determine the effects of metabolic fatigue on knee muscle activation, peak knee joint angles, and peak knee internal moments in young women during 2 jumping tasks. Fifteen women (mean age: 24.6 +/- 2.6 years) participated in one nonfatigued session and one fatigued session. During both sessions, peak knee landing flexion and valgus joint angles, peak knee extension and varus/valgus internal moments, electromyographic (EMG) muscle activity of the quadriceps and hamstrings, and quadriceps/hamstring EMG cocontraction ratio were measured. The tasks consisted of a single-legged drop jump from a 40-cm box and a 20-cm, up-down, repeated hop task. The fatigued session included a Wingate anaerobic protocol followed by performance of the 2 tasks. Although participants exhibited greater knee injury-predisposing factors during the fatigued session, such as lesser knee flexion joint angles, greater knee valgus joint angles, and greater varus/valgus internal joint moments for both tasks, only knee flexion during the up-down task was statistically significant (p = 0.028). Metabolic fatigue may perhaps predispose young women to knee injuries by impairing dynamic knee joint stability. Training strength-endurance components and the ability to maintain control of body movements in either rested or fatigued situations might help reduce injuries in young women athletes. PMID:20300024

  2. Task-related changes in functional properties of the human brain network underlying attentional control.

    Directory of Open Access Journals (Sweden)

    Tetsuo Kida

    Full Text Available Previous studies have demonstrated task-related changes in brain activation and inter-regional connectivity but the temporal dynamics of functional properties of the brain during task execution is still unclear. In the present study, we investigated task-related changes in functional properties of the human brain network by applying graph-theoretical analysis to magnetoencephalography (MEG. Subjects performed a cue-target attention task in which a visual cue informed them of the direction of focus for incoming auditory or tactile target stimuli, but not the sensory modality. We analyzed the MEG signal in the cue-target interval to examine network properties during attentional control. Cluster-based non-parametric permutation tests with the Monte-Carlo method showed that in the cue-target interval, beta activity was desynchronized in the sensori-motor region including premotor and posterior parietal regions in the hemisphere contralateral to the attended side. Graph-theoretical analysis revealed that, in beta frequency, global hubs were found around the sensori-motor and prefrontal regions, and functional segregation over the entire network was decreased during attentional control compared to the baseline. Thus, network measures revealed task-related temporal changes in functional properties of the human brain network, leading to the understanding of how the brain dynamically responds to task execution as a network.

  3. Optimal control model of arm configuration in a reaching task

    Science.gov (United States)

    Yamaguchi, Gary T.; Kakavand, Ali

    1996-05-01

    It was hypothesized that the configuration of the upper limb during a hand static positioning task could be predicted using a dynamic musculoskeletal model and an optimal control routine. Both rhesus monkey and human upper extremity models were formulated, and had seven degrees of freedom (7-DOF) and 39 musculotendon pathways. A variety of configurations were generated about a physiologically measured configuration using the dynamic models and perturbations. The pseudoinverse optimal control method was applied to compute the minimum cost C at each of the generated configurations. Cost function C is described by the Crowninshield-Brand (1981) criterion which relates C (the sum of muscle stresses squared) to the endurance time of a physiological task. The configuration with the minimum cost was compared to the configurations chosen by one monkey (four trials) and by eight human subjects (eight trials each). Results are generally good, but not for all joint angles, suggesting that muscular effort is likely to be one major factor in choosing a preferred static arm posture.

  4. Markov Task Network: A Framework for Service Composition under Uncertainty in Cyber-Physical Systems

    Directory of Open Access Journals (Sweden)

    Abdul-Wahid Mohammed

    2016-09-01

    Full Text Available In novel collaborative systems, cooperative entities collaborate services to achieve local and global objectives. With the growing pervasiveness of cyber-physical systems, however, such collaboration is hampered by differences in the operations of the cyber and physical objects, and the need for the dynamic formation of collaborative functionality given high-level system goals has become practical. In this paper, we propose a cross-layer automation and management model for cyber-physical systems. This models the dynamic formation of collaborative services pursuing laid-down system goals as an ontology-oriented hierarchical task network. Ontological intelligence provides the semantic technology of this model, and through semantic reasoning, primitive tasks can be dynamically composed from high-level system goals. In dealing with uncertainty, we further propose a novel bridge between hierarchical task networks and Markov logic networks, called the Markov task network. This leverages the efficient inference algorithms of Markov logic networks to reduce both computational and inferential loads in task decomposition. From the results of our experiments, high-precision service composition under uncertainty can be achieved using this approach.

  5. Markov Task Network: A Framework for Service Composition under Uncertainty in Cyber-Physical Systems

    Science.gov (United States)

    Mohammed, Abdul-Wahid; Xu, Yang; Hu, Haixiao; Agyemang, Brighter

    2016-01-01

    In novel collaborative systems, cooperative entities collaborate services to achieve local and global objectives. With the growing pervasiveness of cyber-physical systems, however, such collaboration is hampered by differences in the operations of the cyber and physical objects, and the need for the dynamic formation of collaborative functionality given high-level system goals has become practical. In this paper, we propose a cross-layer automation and management model for cyber-physical systems. This models the dynamic formation of collaborative services pursuing laid-down system goals as an ontology-oriented hierarchical task network. Ontological intelligence provides the semantic technology of this model, and through semantic reasoning, primitive tasks can be dynamically composed from high-level system goals. In dealing with uncertainty, we further propose a novel bridge between hierarchical task networks and Markov logic networks, called the Markov task network. This leverages the efficient inference algorithms of Markov logic networks to reduce both computational and inferential loads in task decomposition. From the results of our experiments, high-precision service composition under uncertainty can be achieved using this approach. PMID:27657084

  6. Energy-efficient scheduling for hybrid tasks in control devices for the Internet of Things.

    Science.gov (United States)

    Gao, Zhigang; Wu, Yifan; Dai, Guojun; Xia, Haixia

    2012-01-01

    In control devices for the Internet of Things (IoT), energy is one of the critical restriction factors. Dynamic voltage scaling (DVS) has been proved to be an effective method for reducing the energy consumption of processors. This paper proposes an energy-efficient scheduling algorithm for IoT control devices with hard real-time control tasks (HRCTs) and soft real-time tasks (SRTs). The main contribution of this paper includes two parts. First, it builds the Hybrid tasks with multi-subtasks of different function Weight (HoW) task model for IoT control devices. HoW describes the structure of HRCTs and SRTs, and their properties, e.g., deadlines, execution time, preemption properties, and energy-saving goals, etc. Second, it presents the Hybrid Tasks' Dynamic Voltage Scaling (HTDVS) algorithm. HTDVS first sets the slowdown factors of subtasks while meeting the different real-time requirements of HRCTs and SRTs, and then dynamically reclaims, reserves, and reuses the slack time of the subtasks to meet their ideal energy-saving goals. Experimental results show HTDVS can reduce energy consumption about 10%-80% while meeting the real-time requirements of HRCTs, HRCTs help to reduce the deadline miss ratio (DMR) of systems, and HTDVS has comparable performance with the greedy algorithm and is more favorable to keep the subtasks' ideal speeds.

  7. Formal Derivation of Lotka-Volterra-Haken Amplitude Equations of Task-Related Brain Activity in Multiple, Consecutively Performed Tasks

    Science.gov (United States)

    Frank, T. D.

    The Lotka-Volterra-Haken equations have been frequently used in ecology and pattern formation. Recently, the equations have been proposed by several research groups as amplitude equations for task-related patterns of brain activity. In this theoretical study, the focus is on the circular causality aspect of pattern formation systems as formulated within the framework of synergetics. Accordingly, the stable modes of a pattern formation system inhibit the unstable modes, whereas the unstable modes excite the stable modes. Using this circular causality principle it is shown that under certain conditions the Lotka-Volterra-Haken amplitude equations can be derived from a general model of brain activity akin to the Wilson-Cowan model. The model captures the amplitude dynamics for brain activity patterns in experiments involving several consecutively performed multiple-choice tasks. This is explicitly demonstrated for two-choice tasks involving grasping and walking. A comment on the relevance of the theoretical framework for clinical psychology and schizophrenia is given as well.

  8. An approach to elemental task learning

    Energy Technology Data Exchange (ETDEWEB)

    Belmans, P

    1990-01-01

    In this article we deal with the automated learning of tasks by a robotic system through observation of a human operator. Particularly, we explain what is meant by a learning ability in autonomous robots and in teleoperation systems, where several operators and several machines may work in cooperation to perform tasks. We discuss different approaches to learning in these systems and outline the features of the models they are based upon. This leads us to choose an analytical model suited for tasks analysis. We then present the software architecture for our proposed approach and show the first results obtained on sample tests. 5 refs., 9 figs.

  9. Learning to Model Task-Oriented Attention

    OpenAIRE

    Xiaochun Zou; Xinbo Zhao; Jian Wang; Yongjia Yang

    2016-01-01

    For many applications in graphics, design, and human computer interaction, it is essential to understand where humans look in a scene with a particular task. Models of saliency can be used to predict fixation locations, but a large body of previous saliency models focused on free-viewing task. They are based on bottom-up computation that does not consider task-oriented image semantics and often does not match actual eye movements. To address this problem, we collected eye tracking data of 11 ...

  10. Scheduling optimization of task allocation in integrated manufacturing system based on task decomposition

    Institute of Scientific and Technical Information of China (English)

    Aijun Liu; Michele Pfund; John Fowler

    2016-01-01

    How to deal with the colaboration between task decomposition and task scheduling is the key problem of the integrated manufacturing system for complex products. With the development of manufacturing technology, we can probe a new way to solve this problem. Firstly, a new method for task granularity quantitative analysis is put forward, which can precisely evaluate the task granularity of complex product cooperation workflow in the integrated manufacturing system, on the above basis; this method is used to guide the coarse-grained task decomposition and recombine the sub-tasks with low cohesion coefficient. Then, a multi-objective optimieation model and an algorithm are set up for the scheduling optimization of task scheduling. Finaly, the appli-cation feasibility of the model and algorithm is ultimately vali-dated through an application case study.

  11. Task-free MRI predicts individual differences in brain activity during task performance.

    Science.gov (United States)

    Tavor, I; Parker Jones, O; Mars, R B; Smith, S M; Behrens, T E; Jbabdi, S

    2016-04-01

    When asked to perform the same task, different individuals exhibit markedly different patterns of brain activity. This variability is often attributed to volatile factors, such as task strategy or compliance. We propose that individual differences in brain responses are, to a large degree, inherent to the brain and can be predicted from task-independent measurements collected at rest. Using a large set of task conditions, spanning several behavioral domains, we train a simple model that relates task-independent measurements to task activity and evaluate the model by predicting task activation maps for unseen subjects using magnetic resonance imaging. Our model can accurately predict individual differences in brain activity and highlights a coupling between brain connectivity and function that can be captured at the level of individual subjects.

  12. Interaction between articulatory gestures and inner speech in a counting task.

    Science.gov (United States)

    Cefidekhanie, Ali Hadian; Savariaux, Christophe; Sato, Marc; Schwartz, Jean-Luc

    2014-10-01

    Interaction between covert and overt orofacial gestures has been poorly studied apart from old and rather qualitative experiments. The question deserves special interest in the context of the debate between auditory and motor theories of speech perception, where dual tasks may be of great interest. It is shown here that dynamic mandible and lips movement produced by a participant result in strong and stable perturbations to an inner speech counting task that has to be realized at the same time, while static orofacial configurations and static or dynamic manual actions produce no perturbation. This enables the authors to discuss how such kinds of orofacial perturbations could be introduced in dual task paradigms to assess the role of motor processes in speech perception. PMID:25324087

  13. Makespan and reliability driven scheduling algorithm for independent tasks in Grids

    Institute of Scientific and Technical Information of China (English)

    Wang Shupeng; Yun Xiaochun; Yu Xiangzhan

    2007-01-01

    In the dynamic,complex and unbounded Grid systems,failures of Grid resources caused by malicious attacks and hardware failures ale inevitable and have an adverse effect on the execution of tasks.To mitigate this problem,a makespan and reliability driven(MRD)sufferage scheduling algorithm is designed and implemented.Different from the traditional Grid scheduling algorithms,the algorithm addresses the makespan as well as reliability of tasks.The simulation experimental results show that the MRD sufferage scheduling algorithm can increase reliability of tasks and can trade off reliability against makespan of tasks by adjusting the weighting parameter in its cost function.So it Can be applied to the complex Grid computing environment well.

  14. Solving peg-in-hole tasks by human demonstration and exception strategies

    DEFF Research Database (Denmark)

    Abu-Dakka, Fares; Nemec, Bojan; Kramberger, Aljaz;

    2014-01-01

    Purpose – The purpose of this paper is to propose a new algorithm based on programming by demonstration and exception strategies to solve assembly tasks such as peg-in-hole. Design/methodology/approach – Data describing the demonstrated tasks are obtained by kinesthetic guiding. The demonstrated...... trajectories are transferred to new robot workspaces using three-dimensional (3D) vision. Noise introduced by vision when transferring the task to a new configuration could cause the execution to fail, but such problems are resolved through exception strategies. Findings – This paper demonstrated...... available robot controller. Originality/value – This paper proposes a new approach to the robot assembly based on the Learning by Demonstration (LbD) paradigm. The proposed framework enables to quickly program new assembly tasks without the need for detailed analysis of the geometric and dynamic...

  15. Non-stationary strategies in the resources allocation task of IT project

    OpenAIRE

    Гриша, Олена Василівна

    2011-01-01

    Article deals with distributing of labour resources of IT project choosing of the non-stationary mixed strategy. The simulation model of research of credible implementation of project is given in the conditions of action of factor of novelty of executable works, changes maturity of command and dynamics of risks. The task of optimization of the non-stationary mixed strategy is decided.

  16. Enhancing the Executive Functions of 3-Year-Olds in the Dimensional Change Card Sort Task

    Science.gov (United States)

    Perone, Sammy; Molitor, Stephen J.; Buss, Aaron T.; Spencer, John P.; Samuelson, Larissa K.

    2015-01-01

    Executive functions enable flexible thinking, something young children are notoriously bad at. For instance, in the dimensional change card sort (DCCS) task, 3-year-olds can sort cards by one dimension (shape), but continue to sort by this dimension when asked to switch (to color). This study tests a prediction of a dynamic neural field model that…

  17. The Impact of Task Type and Cognitive Style on Vocabulary Learning

    Science.gov (United States)

    Nezhad, Gholam Reza Haji Pour; Shokrpour, Nasrin

    2012-01-01

    Vocabulary knowledge influences the learners' performance so remarkably that success in all language skills is closely related to it. This vital role necessitates studies focusing on the most effective programs of teaching vocabulary. In this study, we aimed to explore the impact of static versus dynamic task type and the possible interaction with…

  18. Compositional Memory Systems for Multimedia Communicating Tasks

    CERN Document Server

    Molnos, A M; Cotofana, S D; Van Eijndhoven, J T J

    2011-01-01

    Conventional cache models are not suited for real-time parallel processing because tasks may flush each other's data out of the cache in an unpredictable manner. In this way the system is not compositional so the overall performance is difficult to predict and the integration of new tasks expensive. This paper proposes a new method that imposes compositionality to the system?s performance and makes different memory hierarchy optimizations possible for multimedia communicating tasks when running on embedded multiprocessor architectures. The method is based on a cache allocation strategy that assigns sets of the unified cache exclusively to tasks and to the communication buffers. We also analytically formulate the problem and describe a method to compute the cache partitioning ratio for optimizing the throughput and the consumed power. When applied to a multiprocessor with memory hierarchy our technique delivers also performance gain. Compared to the shared cache case, for an application consisting of two jpeg ...

  19. An ergonomic task analysis of spinal anaesthesia.

    LENUS (Irish Health Repository)

    Ajmal, Muhammad

    2009-12-01

    Ergonomics is the study of physical interaction between humans and their working environment. The objective of this study was to characterize the performance of spinal anaesthesia in an acute hospital setting, applying ergonomic task analysis.

  20. Task force report on computerized tomographic scanners

    Energy Technology Data Exchange (ETDEWEB)

    1978-10-01

    Computerized axial tomography (CAT) scanning was the focus of a task force established by the Bergen-Passaic Health Systems Agency in New Jersey. The task force reviewed the literature on CAT technology and its applications, surveyed four northeastern hospitals with operating CAT scanning installations, and created three working subcommittees which produced written reports. It was agreed by task force members that certain criteria should be used when evaluating applications for CAT scanners, e.g., service area, staff resources, emergency room activity, radiotherapy, 24-hour scanner coverage, the medically indigent, and cost. Overall, it was determined that CAT is a proven diagnostic tool of significant value and that it should be available to residents of the Bergen-Passaic health service area. Since the CAT field is rapidly evolving and changing, however, it was not possible to define quantitatively the long-term need for and supply of CAT scanners in the region. Appendixes present supporting data on the task force findings.

  1. Pyramid Lake Task Force : Final report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Pyramid Lake Task Force was created to address Pyramid Lake’s recession and recommend possible solutions that would consider both the needs for preserving the...

  2. Task-based Research and Language Pedagogy.

    Science.gov (United States)

    Ellis, Rod

    2000-01-01

    Examines theoretical views of language use, learning, and teaching that underlie the work on tasks. Two broad and disparate views are identified: the psycholinguistic perspective and a perspective based on sociocultural theory. (Author/VWL)

  3. A Task-driven Grammar Refactoring Algorithm

    Directory of Open Access Journals (Sweden)

    Ivan Halupka

    2012-01-01

    Full Text Available This paper presents our proposal and the implementation of an algorithm for automated refactoring of context-free grammars. Rather than operating under some domain-specific task, in our approach refactoring is perfomed on the basis of a refactoring task defined by its user. The algorithm and the corresponding refactoring system are called mARTINICA. mARTINICA is able to refactor grammars of arbitrary size and structural complexity. However, the computation time needed to perform a refactoring task with the desired outcome is highly dependent on the size of the grammar. Until now, we have successfully performed refactoring tasks on small and medium-size grammars of Pascal-like languages and parts of the Algol-60 programming language grammar. This paper also briefly introduces the reader to processes occurring in grammar refactoring, a method for describing desired properties that a refactored grammar should fulfill, and there is a discussion of the overall significance of grammar refactoring.

  4. Load Balancing in Cloud Computing Environment Using Improved Weighted Round Robin Algorithm for Nonpreemptive Dependent Tasks.

    Science.gov (United States)

    Devi, D Chitra; Uthariaraj, V Rhymend

    2016-01-01

    Cloud computing uses the concepts of scheduling and load balancing to migrate tasks to underutilized VMs for effectively sharing the resources. The scheduling of the nonpreemptive tasks in the cloud computing environment is an irrecoverable restraint and hence it has to be assigned to the most appropriate VMs at the initial placement itself. Practically, the arrived jobs consist of multiple interdependent tasks and they may execute the independent tasks in multiple VMs or in the same VM's multiple cores. Also, the jobs arrive during the run time of the server in varying random intervals under various load conditions. The participating heterogeneous resources are managed by allocating the tasks to appropriate resources by static or dynamic scheduling to make the cloud computing more efficient and thus it improves the user satisfaction. Objective of this work is to introduce and evaluate the proposed scheduling and load balancing algorithm by considering the capabilities of each virtual machine (VM), the task length of each requested job, and the interdependency of multiple tasks. Performance of the proposed algorithm is studied by comparing with the existing methods. PMID:26955656

  5. Load Balancing in Cloud Computing Environment Using Improved Weighted Round Robin Algorithm for Nonpreemptive Dependent Tasks.

    Science.gov (United States)

    Devi, D Chitra; Uthariaraj, V Rhymend

    2016-01-01

    Cloud computing uses the concepts of scheduling and load balancing to migrate tasks to underutilized VMs for effectively sharing the resources. The scheduling of the nonpreemptive tasks in the cloud computing environment is an irrecoverable restraint and hence it has to be assigned to the most appropriate VMs at the initial placement itself. Practically, the arrived jobs consist of multiple interdependent tasks and they may execute the independent tasks in multiple VMs or in the same VM's multiple cores. Also, the jobs arrive during the run time of the server in varying random intervals under various load conditions. The participating heterogeneous resources are managed by allocating the tasks to appropriate resources by static or dynamic scheduling to make the cloud computing more efficient and thus it improves the user satisfaction. Objective of this work is to introduce and evaluate the proposed scheduling and load balancing algorithm by considering the capabilities of each virtual machine (VM), the task length of each requested job, and the interdependency of multiple tasks. Performance of the proposed algorithm is studied by comparing with the existing methods.

  6. Electrophysiological Evidence for Domain-general Processes in Task-switching

    Directory of Open Access Journals (Sweden)

    Mariagrazia eCapizzi

    2016-03-01

    Full Text Available The ability to flexibly switch between tasks is a hallmark of cognitive control. Despite previous studies that have investigated whether different task-switching types would be mediated by distinct or overlapping neural mechanisms, no definitive consensus has been reached on this question yet. Here, we aimed at directly addressing this issue by recording the event-related potentials (ERPs elicited by two types of task-switching occurring in the context of spatial and verbal cognitive domains. Source analysis was also applied to the ERP data in order to track the spatial dynamics of brain activity underlying task-switching abilities. In separate blocks of trials, participants had to perform either spatial or verbal switching tasks both of which employed the same type of stimuli. The ERP analysis, which was carried out through a channel- and time-uninformed mass univariate approach, showed no significant differences between the spatial and verbal domains in the modulation of switch and repeat trials. Specifically, relative to repeat trials, switch trials in both domains were associated with a first larger positivity developing over left parieto-occipital electrodes and with a subsequent larger negativity distributed over mid-left fronto-central sites. The source analysis reconstruction for the two ERP components complemented these findings by highlighting the involvement of left-lateralized prefrontal areas in task-switching. Overall, our results join and extend recent research confirming the existence of left-lateralized domain-general task-switching processes.

  7. Electrophysiological Evidence for Domain-General Processes in Task-Switching.

    Science.gov (United States)

    Capizzi, Mariagrazia; Ambrosini, Ettore; Arbula, Sandra; Mazzonetto, Ilaria; Vallesi, Antonino

    2016-01-01

    The ability to flexibly switch between tasks is a hallmark of cognitive control. Despite previous studies that have investigated whether different task-switching types would be mediated by distinct or overlapping neural mechanisms, no definitive consensus has been reached on this question yet. Here, we aimed at directly addressing this issue by recording the event-related potentials (ERPs) elicited by two types of task-switching occurring in the context of spatial and verbal cognitive domains. Source analysis was also applied to the ERP data in order to track the spatial dynamics of brain activity underlying task-switching abilities. In separate blocks of trials, participants had to perform either spatial or verbal switching tasks both of which employed the same type of stimuli. The ERP analysis, which was carried out through a channel- and time-uninformed mass univariate approach, showed no significant differences between the spatial and verbal domains in the modulation of switch and repeat trials. Specifically, relative to repeat trials, switch trials in both domains were associated with a first larger positivity developing over left parieto-occipital electrodes and with a subsequent larger negativity distributed over mid-left fronto-central sites. The source analysis reconstruction for the two ERP components complemented these findings by highlighting the involvement of left-lateralized prefrontal areas in task-switching. Overall, our results join and extend recent research confirming the existence of left-lateralized domain-general task-switching processes. PMID:27047366

  8. Adaptive Task Assignment in Online Learning Environments

    OpenAIRE

    Andersen, Per-Arne; Kråkevik, Christian; Goodwin, Morten; Yazidi, Anis

    2016-01-01

    With the increasing popularity of online learning, intelligent tutoring systems are regaining increased attention. In this paper, we introduce adaptive algorithms for personalized assignment of learning tasks to student so that to improve his performance in online learning environments. As main contribution of this paper, we propose a a novel Skill-Based Task Selector (SBTS) algorithm which is able to approximate a student's skill level based on his performance and consequently suggest adequa...

  9. Set Shifting Training with Categorization Tasks

    OpenAIRE

    Anna Soveri; Otto Waris; Matti Laine

    2013-01-01

    The very few cognitive training studies targeting an important executive function, set shifting, have reported performance improvements that also generalized to untrained tasks. The present randomized controlled trial extends set shifting training research by comparing previously used cued training with uncued training. A computerized adaptation of the Wisconsin Card Sorting Test was utilized as the training task in a pretest-posttest experimental design involving three groups of university s...

  10. An Architecture for Robot Assemblt Task Planning

    DEFF Research Database (Denmark)

    Sun, Hongyan

    1999-01-01

    This paper discusses an integrated robot assembly task planning system architecture. In such an integrated system, the robot motion commands produced from the planning system can be validated before done-loading for actual execution.......This paper discusses an integrated robot assembly task planning system architecture. In such an integrated system, the robot motion commands produced from the planning system can be validated before done-loading for actual execution....

  11. Information Transfer During a Transitive Reasoning Task

    OpenAIRE

    Brzezicka, Aneta; Kamiński, Maciej; Kamiński, Jan; Blinowska, Katarzyna

    2010-01-01

    For about two decades now, the localization of the brain regions involved in reasoning processes is being investigated through fMRI studies, and it is known that for a transitive form of reasoning the frontal and parietal regions are most active. In contrast, less is known about the information exchange during the performance of such complex tasks. In this study, the propagation of brain activity during a transitive reasoning task was investigated and compared to the propagation during a simp...

  12. Robot Task Learning from Human Demonstration

    OpenAIRE

    Ekvall, Staffan

    2007-01-01

    Today, most robots used in the industry are preprogrammed and require a welldefined and controlled environment. Reprogramming such robots is often a costly process requiring an expert. By enabling robots to learn tasks from human demonstration, robot installation and task reprogramming are simplified. In a longer time perspective, the vision is that robots will move out of factories into our homes and offices. Robots should be able to learn how to set a table or how to fill the dishwasher. Cl...

  13. Limitations in dual-task performance

    OpenAIRE

    Pannebakker, Merel Mathilde

    2009-01-01

    In this thesis, the effect of information-processing overload on working-memory dependent information processing was examined using dual-task paradigms. The experiments described strengthen the importance of a functional explanation for dual-task limitations. First, it showed evidence for a unified coding medium (as put forward in the theory of event coding; Hommel, Müsseler, Aschersleben, & Prinz, 2001) in which features, operations and responses are available and can influence each other. A...

  14. Monitoring supports performance in a dual-task paradigm involving a risky decision-making task and a working memory task

    Directory of Open Access Journals (Sweden)

    Bettina eGathmann

    2015-02-01

    Full Text Available Performing two cognitively demanding tasks at the same time is known to decrease performance. The current study investigates the underlying executive functions of a dual-tasking situation involving the simultaneous performance of decision making under explicit risk and a working memory task. It is suggested that making a decision and performing a working memory task at the same time should particularly require monitoring - an executive control process supervising behavior and the state of processing on two tasks. To test the role of a supervisory/monitoring function in such a dual-tasking situation we investigated 122 participants with the Game of Dice Task plus 2-back task (GDT plus 2-back task. This dual task requires participants to make decisions under risk and to perform a 2-back working memory task at the same time. Furthermore, a task measuring a set of several executive functions gathered in the term concept formation (Modified Card Sorting Test, MCST and the newly developed Balanced Switching Task (BST, measuring monitoring in particular, were used. The results demonstrate that concept formation and monitoring are involved in the simultaneous performance of decision making under risk and a working memory task. In particular, the mediation analysis revealed that BST performance partially mediates the influence of MCST performance on the GDT plus 2-back task. These findings suggest that monitoring is one important subfunction for superior performance in a dual-tasking situation including decision making under risk and a working memory task.

  15. Utilizing Electroencephalography Measurements for Comparison of Task-Specific Neural Efficiencies: Spatial Intelligence Tasks.

    Science.gov (United States)

    Call, Benjamin J; Goodridge, Wade; Villanueva, Idalis; Wan, Nicholas; Jordan, Kerry

    2016-01-01

    Spatial intelligence is often linked to success in engineering education and engineering professions. The use of electroencephalography enables comparative calculation of individuals' neural efficiency as they perform successive tasks requiring spatial ability to derive solutions. Neural efficiency here is defined as having less beta activation, and therefore expending fewer neural resources, to perform a task in comparison to other groups or other tasks. For inter-task comparisons of tasks with similar durations, these measurements may enable a comparison of task type difficulty. For intra-participant and inter-participant comparisons, these measurements provide potential insight into the participant's level of spatial ability and different engineering problem solving tasks. Performance on the selected tasks can be analyzed and correlated with beta activities. This work presents a detailed research protocol studying the neural efficiency of students engaged in the solving of typical spatial ability and Statics problems. Students completed problems specific to the Mental Cutting Test (MCT), Purdue Spatial Visualization test of Rotations (PSVT:R), and Statics. While engaged in solving these problems, participants' brain waves were measured with EEG allowing data to be collected regarding alpha and beta brain wave activation and use. The work looks to correlate functional performance on pure spatial tasks with spatially intensive engineering tasks to identify the pathways to successful performance in engineering and the resulting improvements in engineering education that may follow. PMID:27584838

  16. When predictions take control: The effect of task predictions on task switching performance

    Directory of Open Access Journals (Sweden)

    Wout eDuthoo

    2012-08-01

    Full Text Available In this paper, we aimed to investigate the role of self-generated predictions in the flexible control of behaviour. Therefore, we ran a task switching experiment in which participants were asked to try to predict the upcoming task in three conditions varying in switch rate (30%, 50% and 70%. Irrespective of their predictions, the colour of the target indicated which task participants had to perform. In line with previous studies (Mayr, 2006; Monsell & Mizon, 2006, the switch cost was attenuated as the switch rate increased. Importantly, a clear task repetition bias was found in all conditions, yet the task repetition prediction rate dropped from 78% over 66% to 49% with increasing switch probability in the three conditions. Irrespective of condition, the switch cost was strongly reduced in expectation of a task alternation compared to the cost of an unexpected task alternation following repetition predictions. Hence, our data suggest that the reduction in the switch cost with increasing switch probability is caused by a diminished expectancy for the task to repeat. Taken together, this paper highlights the importance of predictions in the flexible control of behaviour, and suggests a crucial role for task repetition expectancy in the context-sensitive adjusting of task switching performance.

  17. Monkeys are more patient in a foraging task than in a standard intertemporal choice task.

    Directory of Open Access Journals (Sweden)

    Tommy C Blanchard

    Full Text Available Studies of animal impulsivity generally find steep subjective devaluation, or discounting, of delayed rewards - often on the order of a 50% reduction in value in a few seconds. Because such steep discounting is highly disfavored in evolutionary models of time preference, we hypothesize that discounting tasks provide a poor measure of animals' true time preferences. One prediction of this hypothesis is that estimates of time preferences based on these tasks will lack external validity, i.e. fail to predict time preferences in other contexts. We examined choices made by four rhesus monkeys in a computerized patch-leaving foraging task interleaved with a standard intertemporal choice task. Monkeys were significantly more patient in the foraging task than in the intertemporal choice task. Patch-leaving behavior was well fit by parameter-free optimal foraging equations but poorly fit by the hyperbolic discount parameter obtained from the intertemporal choice task. Day-to-day variation in time preferences across the two tasks was uncorrelated with each other. These data are consistent with the conjecture that seemingly impulsive behavior in animals is an artifact of their difficulty understanding the structure of intertemporal choice tasks, and support the idea that animals are more efficient rate maximizers in the multi-second range than intertemporal choice tasks would suggest.

  18. Dynamic HMM Model with Estimated Dynamic Property in Continuous Mandarin Speech Recognition

    Institute of Scientific and Technical Information of China (English)

    CHENFeili; ZHUJie

    2003-01-01

    A new dynamic HMM (hiddem Markov model) has been introduced in this paper, which describes the relationship between dynamic property and feature of space. The method to estimate the dynamic property is discussed in this paper, which makes the dynamic HMMmuch more practical in real time speech recognition. Ex-periment on large vocabulary continuous Mandarin speech recognition task has shown that the dynamic HMM model can achieve about 10% of error reduction both for tonal and toneless syllable. Estimated dynamic property can achieve nearly same (even better) performance than using extracted dynamic property.

  19. 49 CFR 236.1043 - Task analysis and basic requirements.

    Science.gov (United States)

    2010-10-01

    ... of work, etc.), task(s), and desired success rate; (2) Based on a formal task analysis, identify the... performance necessary to perform each task; (5) Develop a training and evaluation curriculum that includes... curriculum and pass an examination that covers the PTC system and appropriate rules and tasks for which...

  20. Sex differences in task distribution and task exposures among Danish house painters:

    DEFF Research Database (Denmark)

    Heilskov-Hansen, Thomas; Svendsen, Susanne Wulff; Thomsen, Jane Frølund;

    2014-01-01

    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......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...... correction were used to evaluate sex differences. RESULTS: Statistically significant (pdifferences 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...