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Sample records for binaural task dynamic

  1. Audibility of time switching in dynamic binaural synthesis

    DEFF Research Database (Denmark)

    Hoffmann, Pablo F.F.; Møller, Henrik

    2005-01-01

    In binaural synthesis, signals are convolved with head-related transfer functions (HRTFs). In dynamic systems, the update is often done by cross- fading between signals that have been filtered in parallel with two HRTFs. An alternative to cross-fading that is attractive in terms of computing powe...

  2. High-frequency binaural beats increase cognitive flexibility: evidence from dual-task crosstalk

    Directory of Open Access Journals (Sweden)

    Bernhard Hommel

    2016-08-01

    Full Text Available Increasing evidence suggests that cognitive-control processes can be configured to optimize either persistence of information processing (by amplifying competition between decision-making alternatives and top-down biasing of this competition or flexibility (by dampening competition and biasing. We investigated whether high-frequency binaural beats, an auditory illusion suspected to act as a cognitive enhancer, have an impact on cognitive-control configuration. We hypothesized that binaural beats in the gamma range bias the cognitive-control style towards flexibility, which in turn should increase the crosstalk between tasks in a dual-task paradigm. We replicated earlier findings that the reaction time in the first-performed task is sensitive to the compatibility between the responses in the first and the second task—an indication of crosstalk. As predicted, exposing participants to binaural beats in the gamma range increased this effect as compared to a control condition in which participants were exposed to a continuous tone of 340 Hz. These findings provide converging evidence that the cognitive-control style can be systematically biased by inducing particular internal states; that high-frequency binaural beats bias the control style towards more flexibility; and that different styles are implemented by changing the strength of local competition and top-down bias.

  3. 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

    communicating over a network protocol (UDP) enabling distribution on several hardware devices. The modules are: Graphical user interface, head tracking server, truck tracking, and binaural synthesis module. The function of the individual modules as well as overall topology of the system will be presented...... 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...... are monitored and taken into account in the binaural sound synthesis. To enable experiments in real traffic, the system facilitates an operator interface where the investigator can position the auditory objects according to real bicycles appearing in the traffic. The software is organized in a number of modules...

  4. Statistics of natural binaural sounds.

    Directory of Open Access Journals (Sweden)

    Wiktor Młynarski

    Full Text Available Binaural sound localization is usually considered a discrimination task, where interaural phase (IPD and level (ILD disparities at narrowly tuned frequency channels are utilized to identify a position of a sound source. In natural conditions however, binaural circuits are exposed to a stimulation by sound waves originating from multiple, often moving and overlapping sources. Therefore statistics of binaural cues depend on acoustic properties and the spatial configuration of the environment. Distribution of cues encountered naturally and their dependence on physical properties of an auditory scene have not been studied before. In the present work we analyzed statistics of naturally encountered binaural sounds. We performed binaural recordings of three auditory scenes with varying spatial configuration and analyzed empirical cue distributions from each scene. We have found that certain properties such as the spread of IPD distributions as well as an overall shape of ILD distributions do not vary strongly between different auditory scenes. Moreover, we found that ILD distributions vary much weaker across frequency channels and IPDs often attain much higher values, than can be predicted from head filtering properties. In order to understand the complexity of the binaural hearing task in the natural environment, sound waveforms were analyzed by performing Independent Component Analysis (ICA. Properties of learned basis functions indicate that in natural conditions soundwaves in each ear are predominantly generated by independent sources. This implies that the real-world sound localization must rely on mechanisms more complex than a mere cue extraction.

  5. 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.

  6. 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.

  7. The Contribution of Matched Envelope Dynamic Range to the Binaural Benefits in Simulated Bilateral Electric Hearing

    Science.gov (United States)

    Chen, Fei; Wong, Lena L. N.; Qiu, Jianxin; Liu, Yehai; Azimi, Behnam; Hu, Yi

    2013-01-01

    Purpose: This study examined the effects of envelope dynamic-range mismatch on the intelligibility of Mandarin speech in noise by simulated bilateral electric hearing. Method: Noise-vocoded Mandarin speech, corrupted by speech-shaped noise at 5 and 0 dB signal-to-noise ratios, was presented unilaterally or bilaterally to 10 normal-hearing…

  8. 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...

  9. Usage of measured reverberation tail in a binaural room impulse response synthesis

    DEFF Research Database (Denmark)

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

    2011-01-01

    utilizing correct acoustical properties of the specific environments. Binaural room impulse response (BRIR) synthesis represents one of the main tasks in the binaural auralization. When the BRIRs are simulated, high order reflections (reverberation tail) are usually modeled statistically because of the high...

  10. 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.

  11. 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

  12. The effect of binaural beats on verbal working memory and cortical connectivity

    Science.gov (United States)

    Beauchene, Christine; Abaid, Nicole; Moran, Rosalyn; Diana, Rachel A.; Leonessa, Alexander

    2017-04-01

    Objective. Synchronization in activated regions of cortical networks affect the brain’s frequency response, which has been associated with a wide range of states and abilities, including memory. A non-invasive method for manipulating cortical synchronization is binaural beats. Binaural beats take advantage of the brain’s response to two pure tones, delivered independently to each ear, when those tones have a small frequency mismatch. The mismatch between the tones is interpreted as a beat frequency, which may act to synchronize cortical oscillations. Neural synchrony is particularly important for working memory processes, the system controlling online organization and retention of information for successful goal-directed behavior. Therefore, manipulation of synchrony via binaural beats provides a unique window into working memory and associated connectivity of cortical networks. Approach. In this study, we examined the effects of different acoustic stimulation conditions during an N-back working memory task, and we measured participant response accuracy and cortical network topology via EEG recordings. Six acoustic stimulation conditions were used: None, Pure Tone, Classical Music, 5 Hz binaural beats, 10 Hz binaural beats, and 15 Hz binaural beats. Main results. We determined that listening to 15 Hz binaural beats during an N-Back working memory task increased the individual participant’s accuracy, modulated the cortical frequency response, and changed the cortical network connection strengths during the task. Only the 15 Hz binaural beats produced significant change in relative accuracy compared to the None condition. Significance. Listening to 15 Hz binaural beats during the N-back task activated salient frequency bands and produced networks characterized by higher information transfer as compared to other auditory stimulation conditions.

  13. 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.

  14. Dynamic Control of Posture Across Locomotor Tasks

    OpenAIRE

    Earhart, Gammon M.

    2013-01-01

    Successful locomotion depends on postural control to establish and maintain appropriate postural orientation of body segments relative to one another and to the environment, and to ensure dynamic stability of the moving body. This paper provides a framework for considering dynamic postural control, highlighting the importance of coordination, consistency, and challenges to postural control posed by various locomotor tasks such as turning and backward walking. The impacts of aging and various ...

  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. Dynamic control of posture across locomotor tasks.

    Science.gov (United States)

    Earhart, Gammon M

    2013-09-15

    Successful locomotion depends on postural control to establish and maintain appropriate postural orientation of body segments relative to one another and to the environment and to ensure dynamic stability of the moving body. This article provides a framework for considering dynamic postural control, highlighting the importance of coordination, consistency, and challenges to postural control posed by various locomotor tasks, such as turning and backward walking. The impacts of aging and various movement disorders on postural control are discussed broadly in an effort to provide a general overview of the field and recommendations for assessment of dynamic postural control across different populations in both clinical and research settings. Suggestions for future research on dynamic postural control during locomotion also are provided and include discussion of opportunities afforded by new and developing technologies, the need for long-term monitoring of locomotor performance in everyday activities, gaps in our knowledge of how targeted intervention approaches modify dynamic postural control, and the relative paucity of literature regarding dynamic postural control in movement disorder populations other than Parkinson's disease.

  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 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.

  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 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

  1. Framing Effects: Dynamics and Task Domains

    Science.gov (United States)

    Wang

    1996-11-01

    The author examines the mechanisms and dynamics of framing effects in risky choices across three distinct task domains (i.e., life-death, public property, and personal money). The choice outcomes of the problems presented in each of the three task domains had a binary structure of a sure thing vs a gamble of equal expected value; the outcomes differed in their framing conditions and the expected values, raging from 6000, 600, 60, to 6, numerically. It was hypothesized that subjects would become more risk seeking, if the sure outcome was below their aspiration level (the minimum requirement). As predicted, more subjects preferred the gamble when facing the life-death choice problems than facing the counterpart problems presented in the other two task domains. Subjects' risk preference varied categorically along the group size dimension in the life-death domain but changed more linearly over the expected value dimension in the monetary domain. Framing effects were observed in 7 of 13 pairs of problems, showing a positive frame-risk aversion and negative frame-risk seeking relationship. In addition, two types of framing effects were theoretically defined and empirically identified. A bidirectional framing effect involves a reversal in risk preference, and occurs when a decision maker's risk preference is ambiguous or weak. Four bidirectional effects were observed; in each case a majority of subjects preferred the sure outcome under a positive frame but the gamble under a negative frame. In contrast, a unidirectional framing effect refers to a preference shift due to the framing of choice outcomes: A majority of subjects preferred one choice outcome (either the sure thing or the gamble) under both framing conditions, with positive frame augmented the preference for the sure thing and negative frame augmented the preference for the gamble. These findings revealed some dynamic regularities of framing effects and posed implications for developing predictive and testable

  2. Musical training enhances neural processing of binaural sounds.

    Science.gov (United States)

    Parbery-Clark, Alexandra; Strait, Dana L; Hittner, Emily; Kraus, Nina

    2013-10-16

    While hearing in noise is a complex task, even in high levels of noise humans demonstrate remarkable hearing ability. Binaural hearing, which involves the integration and analysis of incoming sounds from both ears, is an important mechanism that promotes hearing in complex listening environments. Analyzing inter-ear differences helps differentiate between sound sources--a key mechanism that facilitates hearing in noise. Even when both ears receive the same input, known as diotic hearing, speech intelligibility in noise is improved. Although musicians have better speech-in-noise perception compared with non-musicians, we do not know to what extent binaural processing contributes to this advantage. Musicians often demonstrate enhanced neural responses to sound, however, which may undergird their speech-in-noise perceptual enhancements. Here, we recorded auditory brainstem responses in young adult musicians and non-musicians to a speech stimulus for which there was no musician advantage when presented monaurally. When presented diotically, musicians demonstrated faster neural timing and greater intertrial response consistency relative to non-musicians. Furthermore, musicians' enhancements to the diotically presented stimulus correlated with speech-in-noise perception. These data provide evidence for musical training's impact on biological processes and suggest binaural processing as a possible contributor to more proficient hearing in noise.

  3. 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 perception...... were found not to perceive binaural pitch at all, despite a clear detection of monaural pitch. While both binaural and monaural pitches were detectable by all other listeners, identification scores were significantly lower for binaural than for monaural pitch. A total absence of binaural pitch...... sensation coexisted with a loss of a binaural signal-detection advantage in noise, without implying reduced cognitive function. Auditory filter bandwidths did not correlate with the difference in pitch identification scores between binaural and monaural pitches. However, subjects with impaired binaural...

  4. Leak detection utilizing analog binaural (VLSI) techniques

    Science.gov (United States)

    Hartley, Frank T. (Inventor)

    1995-01-01

    A detection method and system utilizing silicon models of the traveling wave structure of the human cochlea to spatially and temporally locate a specific sound source in the presence of high noise pandemonium. The detection system combines two-dimensional stereausis representations, which are output by at least three VLSI binaural hearing chips, to generate a three-dimensional stereausis representation including both binaural and spectral information which is then used to locate the sound source.

  5. 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....

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. Behavioral sensitivity to broadband binaural localization cues in the ferret.

    Science.gov (United States)

    Keating, Peter; Nodal, Fernando R; Gananandan, Kohilan; Schulz, Andreas L; King, Andrew J

    2013-08-01

    Although the ferret has become an important model species for studying both fundamental and clinical aspects of spatial hearing, previous behavioral work has focused on studies of sound localization and spatial release from masking in the free field. This makes it difficult to tease apart the role played by different spatial cues. In humans and other species, interaural time differences (ITDs) and interaural level differences (ILDs) play a critical role in sound localization in the azimuthal plane and also facilitate sound source separation in noisy environments. In this study, we used a range of broadband noise stimuli presented via customized earphones to measure ITD and ILD sensitivity in the ferret. Our behavioral data show that ferrets are extremely sensitive to changes in either binaural cue, with levels of performance approximating that found in humans. The measured thresholds were relatively stable despite extensive and prolonged (>16 weeks) testing on ITD and ILD tasks with broadband stimuli. For both cues, sensitivity was reduced at shorter durations. In addition, subtle effects of changing the stimulus envelope were observed on ITD, but not ILD, thresholds. Sensitivity to these cues also differed in other ways. Whereas ILD sensitivity was unaffected by changes in average binaural level or interaural correlation, the same manipulations produced much larger effects on ITD sensitivity, with thresholds declining when either of these parameters was reduced. The binaural sensitivity measured in this study can largely account for the ability of ferrets to localize broadband stimuli in the azimuthal plane. Our results are also broadly consistent with data from humans and confirm the ferret as an excellent experimental model for studying spatial hearing.

  11. Dynamic task-allocation for Unmanned Aircraft Systems

    Science.gov (United States)

    Bakker, Tim

    This dissertation addresses improvements to a consensus based task allocation algorithms for improving the Quality of Service in multi-task and multi-agent environments. Research in the past has led to many centralized task allocation algorithms where a central computation unit is calculating the global optimum task allocation solution. The centralized algorithms are plagued by creating a single point of failure and the bandwidth needed for creating consistent and accurate situational awareness off all agents. This work will extend upon a widely researched decentralized task assignment algorithm based on the consensus principle. Although many extensions have led to improvements of the original algorithm, there is still much opportunity for improvement in providing sufficient and reliable task assignments in real-world dynamic conditions and changing environments. This research addresses practical changes made to the consensus based task allocation algorithms for improving the Quality of Service in multi-task and multi-agent environments.

  12. Auditory driving of the autonomic nervous system: Listening to theta-frequency binaural beats post-exercise increases parasympathetic activation and sympathetic withdrawal.

    Science.gov (United States)

    McConnell, Patrick A; Froeliger, Brett; Garland, Eric L; Ives, Jeffrey C; Sforzo, Gary A

    2014-01-01

    Binaural beats are an auditory illusion perceived when two or more pure tones of similar frequencies are presented dichotically through stereo headphones. Although this phenomenon is thought to facilitate state changes (e.g., relaxation), few empirical studies have reported on whether binaural beats produce changes in autonomic arousal. Therefore, the present study investigated the effects of binaural beating on autonomic dynamics [heart rate variability (HRV)] during post-exercise relaxation. Subjects (n = 21; 18-29 years old) participated in a double-blind, placebo-controlled study during which binaural beats and placebo were administered over two randomized and counterbalanced sessions (within-subjects repeated-measures design). At the onset of each visit, subjects exercised for 20-min; post-exercise, subjects listened to either binaural beats ('wide-band' theta-frequency binaural beats) or placebo (carrier tones) for 20-min while relaxing alone in a quiet, low-light environment. Dependent variables consisted of high-frequency (HF, reflecting parasympathetic activity), low-frequency (LF, reflecting sympathetic and parasympathetic activity), and LF/HF normalized powers, as well as self-reported relaxation. As compared to the placebo visit, the binaural-beat visit resulted in greater self-reported relaxation, increased parasympathetic activation and increased sympathetic withdrawal. By the end of the 20-min relaxation period there were no observable differences in HRV between binaural-beat and placebo visits, although binaural-beat associated HRV significantly predicted subsequent reported relaxation. Findings suggest that listening to binaural beats may exert an acute influence on both LF and HF components of HRV and may increase subjective feelings of relaxation.

  13. Development of binaural speech transmission index

    NARCIS (Netherlands)

    Wijngaarden, S.J. van; Drullman, R.

    2006-01-01

    Although the speech transmission index (STI) is a well-accepted and standardized method for objective prediction of speech intelligibility in a wide range of-environments and applications, it is essentially a monaural model. Advantages of binaural hearing to the intelligibility of speech are disrega

  14. Binaural Processing of Multiple Sound Sources

    Science.gov (United States)

    2016-08-18

    feedback was provided to the listener about their rotation, so there was no cognitive information based on experience that was related to their rotation...overlap on sensitivity to interaural time differences, EL : Possible Role of Binaural Interference, Journal of the Acoustical Society of America 137

  15. Dynamics of Cooperation in a Task Completion Social Dilemma

    Science.gov (United States)

    Passino, Kevin M.

    2017-01-01

    We study the situation where the members of a community have the choice to participate in the completion of a common task. The process of completing the task involves only costs and no benefits to the individuals that participate in this process. However, completing the task results in changes that significantly benefit the community and that exceed the participation efforts. A task completion social dilemma arises when the short-term participation costs dissipate any interest in the community members to contribute to the task completion process and therefore to obtain the benefits that result from completing the task. In this work, we model the task completion problem using a dynamical system that characterizes the participation dynamics in the community and the task completion process. We show how this model naturally allows for the incorporation of several mechanisms that facilitate the emergence of cooperation and that have been studied in previous research on social dilemmas, including communication across a network, and indirect reciprocity through relative reputation. We provide mathematical analyses and computer simulations to study the qualitative properties of the participation dynamics in the community for different scenarios. PMID:28125721

  16. Designing and Examining the Effects of a Dynamic Geometry Task Analysis Framework on Teachers' Written Geometer's Sketchpad Tasks

    Science.gov (United States)

    Trocki, Aaron David

    2015-01-01

    This study investigates the usefulness of a Dynamic Geometry Task Analysis Framework for indicating task quality in dynamic geometry environments in general, and The Geometer's Sketchpad in particular. This research sought to first establish the validity of the framework for indicating task quality, and to second explore the effects of the…

  17. Multi-task Gaussian Process Learning of Robot Inverse Dynamics

    OpenAIRE

    Chai, Kian Ming; Williams, Christopher K. I.; Klanke, Stefan; Vijayakumar, Sethu

    2008-01-01

    The inverse dynamics problem for a robotic manipulator is to compute the torques needed at the joints to drive it along a given trajectory; it is beneficial to be able to learn this function for adaptive control. A robotic manipulator will often need to be controlled while holding different loads in its end effector, giving rise to a multi-task learning problem. By placing independent Gaussian process priors over the latent functions of the inverse dynamics, we obtain a multi-t...

  18. Dynamic Task Performance, Cohesion, and Communications in Human Groups.

    Science.gov (United States)

    Giraldo, Luis Felipe; Passino, Kevin M

    2016-10-01

    In the study of the behavior of human groups, it has been observed that there is a strong interaction between the cohesiveness of the group, its performance when the group has to solve a task, and the patterns of communication between the members of the group. Developing mathematical and computational tools for the analysis and design of task-solving groups that are not only cohesive but also perform well is of importance in social sciences, organizational management, and engineering. In this paper, we model a human group as a dynamical system whose behavior is driven by a task optimization process and the interaction between subsystems that represent the members of the group interconnected according to a given communication network. These interactions are described as attractions and repulsions among members. We show that the dynamics characterized by the proposed mathematical model are qualitatively consistent with those observed in real-human groups, where the key aspect is that the attraction patterns in the group and the commitment to solve the task are not static but change over time. Through a theoretical analysis of the system we provide conditions on the parameters that allow the group to have cohesive behaviors, and Monte Carlo simulations are used to study group dynamics for different sets of parameters, communication topologies, and tasks to solve.

  19. 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.

  20. 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

  1. Usage of measured reverberation tail in a binaural room impulse response synthesis

    DEFF Research Database (Denmark)

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

    2011-01-01

    utilizing correct acoustical properties of the specific environments. Binaural room impulse response (BRIR) synthesis represents one of the main tasks in the binaural auralization. When the BRIRs are simulated, high order reflections (reverberation tail) are usually modeled statistically because of the high...... measurement in a real room is performed. In the second one, synthesized BRIRs are used. BRIRs synthesis is realized using the image-source method for the early reflections and the artificial reverberation algorithm for the reverberation tail. The third case combines modeled early reflections from the second...... case and measured late reverberation from the first one. All three cases are evaluated and compared objectively based on the obtained room acoustic parameters as well as subjectively by listening tests....

  2. 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...

  3. User-Assisted Store Recycling for Dynamic Task Graph Schedulers

    Energy Technology Data Exchange (ETDEWEB)

    Kurt, Mehmet Can [Quantcast Corporation, San Francisco, CA; Krishnamoorthy, Sriram [Pacific Northwest National Laboratory, Richland, WA; Agrawal, Gagan [The Ohio State University, Neil Avenue Columbus, OH; Ren, Bin [The College of William and Mary, Williamsburg, VA

    2016-12-28

    The emergence of the multi-core era has led to increased interest in designing effective yet practical parallel programming models. Models based on task graphs that operate on single-assignment data are attractive in several ways: they can support dynamic applications and precisely represent the available concurrency. However, they also require nuanced algorithms for scheduling and memory management for efficient execution. In this paper, we consider memory-efficient dynamic scheduling of task graphs. Specifically, we present a novel approach for dynamically recycling the memory locations assigned to data items as they are produced by tasks. We develop algorithms to identify memory-efficient store recycling functions by systematically evaluating the validity of a set of (user-provided or automatically generated) alternatives. Because recycling function can be input data-dependent, we have also developed support for continued correct execution of a task graph in the presence of a potentially incorrect store recycling function. Experimental evaluation demonstrates that our approach to automatic store recycling incurs little to no overheads, achieves memory usage comparable to the best manually derived solutions, often produces recycling functions valid across problem sizes and input parameters, and efficiently recovers from an incorrect choice of store recycling functions.

  4. 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...

  5. 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.

  6. Stochastic dynamic programming applied to planning of robot grinding tasks

    Energy Technology Data Exchange (ETDEWEB)

    Brown, M.L. (Digital Equipment Corp., Shrewsbury, MA (United States)); Whitney, D.E. (Massachusetts Inst. of Technology, Cambridge, MA (United States))

    1994-10-01

    This paper proposes an intelligent manufacturing system that can make decisions about the process in light of the uncertain outcome of these decisions and attempts to minimize the expected economic penalty resulting from those decisions. It uses robot weld bead grinding as an example of a process with significant process variations. The need for multiple grinding passes, the poor predictability of those passes, the task requirements, and the process constraints conspire to make planning and controlling weld bead grinding a formidable probe. A three tier hierarchical control system is proposed to plan an optimal sequence of grinding passes, dynamically simulate each pass, execute the planned sequence of controlled grinding passes, and modify the pass sequence as grinding continues. The top tier, described in this paper, plans the grinding sequence for each weld bead, and is implemented using Stochastic Dynamic Programming, selecting the volumetric removal and feedspeed for each pass in order to optimize the satisfaction of the task requirements by the entire grinding sequence within the equipment, task, and process constraints. The resulting optimal policies have quite complex structures, showing foresight, anxiety, indifference, and aggressiveness, depending upon the situation.

  7. 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)...

  8. Binaural masking level differences with a variety of waveforms.

    Science.gov (United States)

    Henning, G B; Gaskell, H

    1981-05-01

    Binaural masking level differences (BMLDs) were measured in a standard two-interval forced-choice detection task. The signals were (a) 250-ms bursts of pure tones, (b) amplitude-modulated waveforms with either high- or low-frequency carriers, and (c) 20-microseconds clicks. The pure tones and clicks were presented either eith zero phase difference between the ears or with an 180 degrees phase difference between the ears: the AM tones were presented in several different interaural phase conditions, only some of which lead to changes in the apparent location of the signal source. The noise against which all the signals were detected was white, broad-band, and identical at the ears. BMLDs were invariably small with high-frequency signals and with clicks. Although the magnitude of the BMLD obtained with low-frequency signals appeared to be related to the Observers' ability to lateralize the signal, there is a simpler explanation based on the assumption that detection of low-frequency AM signals is determined by independent detection of its components.

  9. 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.

  10. 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...

  11. Task Dynamics in a College Biology Course for Prospective Elementary Teachers.

    Science.gov (United States)

    Moscovici, Hedy

    2001-01-01

    Explores the dynamic profile of a task as interpreted by a group of six prospective elementary teachers enrolled in a college biology course. Describes the shift from a planned task to a transitional task and finally an enacted task. (Author/MM)

  12. 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.

  13. Dynamics of serial position change in probe-recognition task

    Directory of Open Access Journals (Sweden)

    Fifić Mario

    2002-01-01

    Full Text Available Relationship between practice and serial position effects was investigated, in order to obtain more evidence for underlying short-term memory processes. The investigated relationship is termed the dynamics of serial position change. To address this issue, the present study investigated mean latency, errors, and performed Ex-Gaussian convolution analysis. In six-block trials the probe-recognition task was used in the so-called fast experimental procedure. The serial position effect was significant in all six blocks. Both primacy and recency effects were detected, with primacy located in the first two blocks, producing a non-linear serial position effect. Although the serial position function became linear from the third block on, the convolution analysis revealed a non-linear change of the normal distribution parameter, suggesting special status of the last two serial positions. Further, separation of convolution parameters for serial position and practice was observed, suggesting different underlying mechanisms. In order to account for these findings, a strategy shift mechanism is suggested, rather then a mechanism based on changing the manner of memory scanning. Its influence is primarily located at the very beginning of the experimental session. The pattern of results of errors regarding the dynamics of serial position change closely paralleled those on reaction times. Several models of short-term memory were evaluated in order to account for these findings.

  14. 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

  15. Monaural and binaural subjective modulation transfer functions in simple reverberation

    DEFF Research Database (Denmark)

    2008-01-01

    , M.R. (1981) Modulation transfer-functions: Definition and measurement, Acustica, 49, 179-182]. The envelope of a speech signal is critical for intelligibility, and the speech transmission index (STI) predicts the intelligibility of speech through a given transmission channel based on its MTF...... [Houtgast, T. and Steeneken, H.J.M. (1973) Modulation transfer-function in room acoustics as a predictor of speech intelligibility, Acustica, 28, 66-73]. In the present study, the results of intensity modulation detection experiments with broad-band noise carriers are reported in monaural and binaural...... give a binaural advantage in detecting the intensity modulation. This binaural advantage could be used to enhance speech intelligibility over purely monaural listening....

  16. 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

  17. Calibration aspects of binaural sound reproduction over insert earphones

    DEFF Research Database (Denmark)

    Hoffmann, Pablo F.; Markovic, Milos; Olesen, Søren Krarup

    2012-01-01

    in earphone-based reproduction, binaural reproduction can be applied directly. This paper is concerned with the theoretical and practical aspects relevant to the correct reproduction of binaural signals over insert earphones. To this purpose, a theoretical model originally developed to explain the acoustic......Earphones are nowadays widely adopted for the reproduction of audio material in mobile multimedia and communication platforms, e.g. smartphones. Reproduction of high-quality spatial sound on such platforms can dramatically improve their applicability, and since two channels are always available...

  18. 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...... of externalization of speech and noise stimuli was tested in a listening experiment with a multi-stimulus test. No influence was found for the stimulus signal, but the externalization scores were found to be lower for 0◦ incidence. With all microphones, relatively high externalization scores were achieved...

  19. 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...

  20. A novel binaural pitch elicited by phase-modulated noise: MEG and psychophysical observations.

    Science.gov (United States)

    Witton, Caroline; Hillebrand, Arjan; Furlong, Paul L; Henning, G Bruce

    2012-06-01

    Binaural pitches are auditory percepts that emerge from combined inputs to the ears but that cannot be heard if the stimulus is presented to either ear alone. Here, we describe a binaural pitch that is not easily accommodated within current models of binaural processing. Convergent magnetoencephalography (MEG) and psychophysical measurements were used to characterize the pitch, heard when band-limited noise had a rapidly changing interaural phase difference. Several interesting features emerged: First, the pitch was perceptually lateralized, in agreement with the lateralization of the evoked changes in MEG spectral power, and its salience depended on dichotic binaural presentation. Second, the frequency of the pure tone that matched the binaural pitch lay within a lower spectral sideband of the phase-modulated noise and followed the frequency of that sideband when the modulation frequency or center frequency and bandwidth of the noise changed. Thus, the binaural pitch depended on the processing of binaural information in that lower sideband.

  1. 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

  2. Biologically plausible learning in recurrent neural networks reproduces neural dynamics observed during cognitive tasks.

    Science.gov (United States)

    Miconi, Thomas

    2017-02-23

    Neural activity during cognitive tasks exhibits complex dynamics that flexibly encode task-relevant variables. Chaotic recurrent networks, which spontaneously generate rich dynamics, have been proposed as a model of cortical computation during cognitive tasks. However, existing methods for training these networks are either biologically implausible, and/or require a continuous, real-time error signal to guide learning. Here we show that a biologically plausible learning rule can train such recurrent networks, guided solely by delayed, phasic rewards at the end of each trial. Networks endowed with this learning rule can successfully learn nontrivial tasks requiring flexible (context-dependent) associations, memory maintenance, nonlinear mixed selectivities, and coordination among multiple outputs. The resulting networks replicate complex dynamics previously observed in animal cortex, such as dynamic encoding of task features and selective integration of sensory inputs. We conclude that recurrent neural networks offer a plausible model of cortical dynamics during both learning and performance of flexible behavior.

  3. Dynamic Scheduling Real-Time Task Using Primary-Backup Overloading Strategy for Multiprocessor Systems

    Science.gov (United States)

    Sun, Wei; Yu, Chen; Défago, Xavier; Inoguchi, Yasushi

    The scheduling of real-time tasks with fault-tolerant requirements has been an important problem in multiprocessor systems. The primary-backup (PB) approach is often used as a fault-tolerant technique to guarantee the deadlines of tasks despite the presence of faults. In this paper we propose a dynamic PB-based task scheduling approach, wherein an allocation parameter is used to search the available time slots for a newly arriving task, and the previously scheduled tasks can be re-scheduled when there is no available time slot for the newly arriving task. In order to improve the schedulability we also propose an overloading strategy for PB-overloading and Backup-backup (BB) overloading. Our proposed task scheduling algorithm is compared with some existing scheduling algorithms in the literature through simulation studies. The results have shown that the task rejection ratio of our real-time task scheduling algorithm is almost 50% lower than the compared algorithms.

  4. 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...

  5. Binaural intelligibility prediction based on the speech transmission index

    NARCIS (Netherlands)

    Wijngaarden, S.J. van; Drullman, R.

    2008-01-01

    Although the speech transmission index STI is a well-accepted and standardized method for objective prediction of speech intelligibility in a wide range of environments and applications, it is essentially a monaural model. Advantages of binaural hearing in speech intelligibility are disregarded. In

  6. 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.

  7. Dynamic Task-Scheduling in Grid Computing using Prioritized Round Robin Algorithm

    Directory of Open Access Journals (Sweden)

    Sunita Bansal

    2011-03-01

    Full Text Available Over the years, grid computing has emerged as one of the most viable and scalable alternatives to high performance supercomputing, tapping into computing power of the order of Gigaflops. However, the inherent dynamicity in grid computing has made it extremely difficult to come up with near-optimal solutions to efficiently schedule tasks in grids. The present paper proposes a novel grid-scheduling heuristic that adaptively and dynamically schedules tasks without requiring any prior information on the workload of incoming tasks. The approach models the grid system in the form of a state-transition diagram, employing a prioritized round-robin algorithm with task replication to optimally schedule tasks, using prediction information on processor utilization of individual nodes. Simulations, comparing the proposed approach with the round-robin heuristic, have shown the given heuristic to be more effective in scheduling tasks as compared to the latter.

  8. Teachers' Use of Transnumeration in Solving Statistical Tasks with Dynamic Statistical Software

    Science.gov (United States)

    Lee, Hollylynne S.; Kersaint, Gladis; Harper, Suzanne R.; Driskell, Shannon O.; Jones, Dusty L.; Leatham, Keith R.; Angotti, Robin L.; Adu-Gyamfi, Kwaku

    2014-01-01

    This study examined a random stratified sample (n = 62) of teachers' work across eight institutions on three tasks that utilized dynamic statistical software. We considered how teachers may utilize and develop their statistical knowledge and technological statistical knowledge when investigating a statistical task. We examined how teachers engaged…

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

    NARCIS (Netherlands)

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

    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

  10. Rate-Constrained Beamforming in Binaural Hearing Aids

    Science.gov (United States)

    Srinivasan, Sriram; den Brinker, Albertus C.

    2009-12-01

    Recently, hearing aid systems where the left and right ear devices collaborate with one another have received much attention. Apart from supporting natural binaural hearing, such systems hold great potential for improving the intelligibility of speech in the presence of noise through beamforming algorithms. Binaural beamforming for hearing aids requires an exchange of microphone signals between the two devices over a wireless link. This paper studies two problems: which signal to transmit from one ear to the other, and at what bit-rate. The first problem is relevant as modern hearing aids usually contain multiple microphones, and the optimal choice for the signal to be transmitted is not obvious. The second problem is relevant as the capacity of the wireless link is limited by stringent power consumption constraints imposed by the limited battery life of hearing aids.

  11. Rate-Constrained Beamforming in Binaural Hearing Aids

    Directory of Open Access Journals (Sweden)

    Sriram Srinivasan

    2009-01-01

    Full Text Available Recently, hearing aid systems where the left and right ear devices collaborate with one another have received much attention. Apart from supporting natural binaural hearing, such systems hold great potential for improving the intelligibility of speech in the presence of noise through beamforming algorithms. Binaural beamforming for hearing aids requires an exchange of microphone signals between the two devices over a wireless link. This paper studies two problems: which signal to transmit from one ear to the other, and at what bit-rate. The first problem is relevant as modern hearing aids usually contain multiple microphones, and the optimal choice for the signal to be transmitted is not obvious. The second problem is relevant as the capacity of the wireless link is limited by stringent power consumption constraints imposed by the limited battery life of hearing aids.

  12. 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.

  13. 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

    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......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...

  14. Biologically inspired binaural hearing aid algorithms: Design principles and effectiveness

    Science.gov (United States)

    Feng, Albert

    2002-05-01

    Despite rapid advances in the sophistication of hearing aid technology and microelectronics, listening in noise remains problematic for people with hearing impairment. To solve this problem two algorithms were designed for use in binaural hearing aid systems. The signal processing strategies are based on principles in auditory physiology and psychophysics: (a) the location/extraction (L/E) binaural computational scheme determines the directions of source locations and cancels noise by applying a simple subtraction method over every frequency band; and (b) the frequency-domain minimum-variance (FMV) scheme extracts a target sound from a known direction amidst multiple interfering sound sources. Both algorithms were evaluated using standard metrics such as signal-to-noise-ratio gain and articulation index. Results were compared with those from conventional adaptive beam-forming algorithms. In free-field tests with multiple interfering sound sources our algorithms performed better than conventional algorithms. Preliminary intelligibility and speech reception results in multitalker environments showed gains for every listener with normal or impaired hearing when the signals were processed in real time with the FMV binaural hearing aid algorithm. [Work supported by NIH-NIDCD Grant No. R21DC04840 and the Beckman Institute.

  15. Multi-heuristic dynamic task allocation using genetic algorithms in a heterogeneous distributed system.

    Science.gov (United States)

    Page, Andrew J; Keane, Thomas M; Naughton, Thomas J

    2010-07-01

    We present a multi-heuristic evolutionary task allocation algorithm to dynamically map tasks to processors in a heterogeneous distributed system. It utilizes a genetic algorithm, combined with eight common heuristics, in an effort to minimize the total execution time. It operates on batches of unmapped tasks and can preemptively remap tasks to processors. The algorithm has been implemented on a Java distributed system and evaluated with a set of six problems from the areas of bioinformatics, biomedical engineering, computer science and cryptography. Experiments using up to 150 heterogeneous processors show that the algorithm achieves better efficiency than other state-of-the-art heuristic algorithms.

  16. Task-related Functional Connectivity Dynamics in a Block-designed Visual Experiment

    Directory of Open Access Journals (Sweden)

    Xin eDi

    2015-09-01

    Full Text Available Studying task modulations of brain connectivity using functional magnetic resonance imaging (fMRI is critical to understand brain functions that support cognitive and affective processes. Existing methods such as psychophysiological interaction (PPI and dynamic causal modelling (DCM usually implicitly assume that the connectivity patterns are stable over a block-designed task with identical stimuli. However, this assumption lacks empirical verification on high-temporal resolution fMRI data with reliable data-driven analysis methods. The present study performed a detailed examination of dynamic changes of functional connectivity (FC in a simple block-designed visual checkerboard experiment with a sub-second sampling rate (TR = 0.645 s by estimating time-varying correlation coefficient (TVCC between BOLD responses of different brain regions. We observed reliable task-related FC changes (i.e., FCs were transiently decreased after task onset and went back to the baseline afterward among several visual regions of the bilateral middle occipital gyrus (MOG and the bilateral fusiform gyrus (FuG. Importantly, only the FCs between higher visual regions (MOG and lower visual regions (FuG exhibited such dynamic patterns. The results suggested that simply assuming a sustained FC during a task block may be insufficient to capture distinct task-related FC changes. The investigation of FC dynamics in tasks could improve our understanding of condition shifts and the coordination between different activated brain regions.

  17. 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

  18. On the temporal dynamics of spatial stimulus-response transfer between spatial incompatibility and Simon tasks

    Directory of Open Access Journals (Sweden)

    Jason eIvanoff

    2014-08-01

    Full Text Available The Simon effect refers to the performance (response time and accuracy advantage for responses that spatially correspond to the task-irrelevant location of a stimulus. It has been attributed to a natural tendency to respond toward the source of stimulation. When location is task-relevant, however, and responses are intentionally directed away (incompatible or towards (compatible the source of the stimulation, there is also an advantage for spatially compatible responses over spatially incompatible responses. Interestingly, a number of studies have demonstrated a reversed, or reduced, Simon effect following practice with a spatial incompatibility task. One interpretation of this finding is that practicing a spatial incompatibility task disables the natural tendency to respond toward stimuli. Here, the temporal dynamics of this stimulus-response (S-R transfer were explored with speed-accuracy trade-offs (SATs. All experiments used the mixed-task paradigm in which Simon and spatial compatibility/incompatibility tasks were interleaved across blocks of trials. In general, bidirectional S-R transfer was observed: while the spatial incompatibility task had an influence on the Simon effect, the task-relevant S-R mapping of the Simon task also had a small impact on congruency effects within the spatial compatibility and incompatibility tasks. These effects were generally greater when the task contexts were similar. Moreover, the SAT analysis of performance in the Simon task demonstrated that the tendency to respond to the location of the stimulus was not eliminated because of the spatial incompatibility task. Rather, S-R transfer from the spatial incompatibility task appeared to partially mask the natural tendency to respond to the source of stimulation with a conflicting inclination to respond away from it. These findings support the use of SAT methodology to quantitatively describe rapid response tendencies.

  19. Dynamic Sensor Tasking for Space Situational Awareness via Reinforcement Learning

    Science.gov (United States)

    Linares, R.; Furfaro, R.

    2016-09-01

    This paper studies the Sensor Management (SM) problem for optical Space Object (SO) tracking. The tasking problem is formulated as a Markov Decision Process (MDP) and solved using Reinforcement Learning (RL). The RL problem is solved using the actor-critic policy gradient approach. The actor provides a policy which is random over actions and given by a parametric probability density function (pdf). The critic evaluates the policy by calculating the estimated total reward or the value function for the problem. The parameters of the policy action pdf are optimized using gradients with respect to the reward function. Both the critic and the actor are modeled using deep neural networks (multi-layer neural networks). The policy neural network takes the current state as input and outputs probabilities for each possible action. This policy is random, and can be evaluated by sampling random actions using the probabilities determined by the policy neural network's outputs. The critic approximates the total reward using a neural network. The estimated total reward is used to approximate the gradient of the policy network with respect to the network parameters. This approach is used to find the non-myopic optimal policy for tasking optical sensors to estimate SO orbits. The reward function is based on reducing the uncertainty for the overall catalog to below a user specified uncertainty threshold. This work uses a 30 km total position error for the uncertainty threshold. This work provides the RL method with a negative reward as long as any SO has a total position error above the uncertainty threshold. This penalizes policies that take longer to achieve the desired accuracy. A positive reward is provided when all SOs are below the catalog uncertainty threshold. An optimal policy is sought that takes actions to achieve the desired catalog uncertainty in minimum time. This work trains the policy in simulation by letting it task a single sensor to "learn" from its performance

  20. Dynamic Fair Priority Optimization Task Scheduling Algorithm in Cloud Computing: Concepts and Implementations

    Directory of Open Access Journals (Sweden)

    Deepika Saxena

    2016-02-01

    Full Text Available Cloud computing has become buzzword today. It is a digital service where dynamically scalable and virtualized resources are provided as a service over internet. Task scheduling is premier research topic in cloud computing. It is always a challenging task to map variety of complex task on various available heterogenous resources in scalable and efficient way. The very objective of this paper is to dynamically optimize task scheduling at system level as well as user level. This paper relates benefit-fairness algorithm based on weighted-fair Queuing model which is much more efficient than simple priority queuing. In proposed algorithm, we have classified and grouped all tasks as deadline based and minimum cost based constraints and after dynamic optimization, priority of fairness is applied. Here different priority queue (high, mid, low are implemented in round-robin fashion as per weights assign to them .We recompile the CloudSim and simulate the proposed algorithm and results of this algorithm is compared with sequential task scheduling and simple constraints (cost and deadline based task scheduling algorithm. The experimental results indicates that proposed algorithm is, not only beneficial to user and service provider, but also provides better efficiency and fairness at priority level, i.e. benefit at system level.

  1. Geospace Plasma Dynamics Laboratory Annual Task Report (FY11)

    Science.gov (United States)

    2012-03-01

    and the other stability properties of the ion-cyclotron instability in various non - Maxwellian plasmas . For this purpose, analysis of the kinetic... Plasma Dynamics.” The goal of this research effort is to develop a detailed knowledge of the space environment by analyzing satellite data and...Furthermore, satellite-measured particle velocity distributions in the magnetosphere are often better modeled by non - Maxwellian distributions, such as

  2. A heart for interaction: Shared physiological dynamics and behavioral coordination in a collective, creative construction task.

    Science.gov (United States)

    Fusaroli, Riccardo; Bjørndahl, Johanne S; Roepstorff, Andreas; Tylén, Kristian

    2016-09-01

    Interpersonally shared physiological dynamics are increasingly argued to underlie rapport, empathy, and even team performance. Inspired by the model of interpersonal synergy, we critically investigate the presence, temporal development, possible mechanisms and impact of shared interpersonal heart rate (HR) dynamics during individual and collective creative LEGO® construction tasks. In Study 1 we show how shared HR dynamics are driven by a plurality of sources, including task constraints and behavioral coordination. Generally, shared HR dynamics are more prevalent in individual trials (involving 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. Furthermore, in contrast to individual trials, shared HR dynamics are found to increase across collective trials. Study 2 investigates which aspects of social interaction might drive these effects. We show that shared HR dynamics are statistically predicted by interpersonal speech and building coordination. In Study 3, we explore the relation between HR dynamics, behavioral coordination, and self-reported measures of rapport and group competence. Although behavioral coordination predicts rapport and group competence, shared HR dynamics do not. Although shared physiological dynamics were reliably observed in our study, our results warrant not to consider HR dynamics a general driving mechanism of social coordination. Behavioral coordination-on the other hand-seems to be more informative of both shared physiological dynamics and collective experience. (PsycINFO Database Record

  3. 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...

  4. 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

    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...

  5. 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...

  6. 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

  7. 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...

  8. Scheduling Algorithm: Tasks Scheduling Algorithm for Multiple Processors with Dynamic Reassignment

    Directory of Open Access Journals (Sweden)

    Pradeep Kumar Yadav

    2008-01-01

    Full Text Available Distributed computing systems [DCSs] offer the potential for improved performance and resource sharing. To make the best use of the computational power available, it is essential to assign the tasks dynamically to that processor whose characteristics are most appropriate for the execution of the tasks in distributed processing system. We have developed a mathematical model for allocating “M” tasks of distributed program to “N” multiple processors (M>N that minimizes the total cost of the program. Relocating the tasks from one processor to another at certain points during the course of execution of the program that contributes to the total cost of the running program has been taken into account. Phasewise execution cost [EC], intertask communication cost [ITCT], residence cost [RC] of each task on different processors, and relocation cost [REC] for each task have been considered while preparing a dynamic tasks allocation model. The present model is suitable for arbitrary number of phases and processors with random program structure.

  9. 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/).

  10. Detrending Changes the Temporal Dynamics of a Semantic Fluency Task.

    Science.gov (United States)

    Lenio, Steven; Lissemore, Frances M; Sajatovic, Martha; Smyth, Kathleen A; Tatsuoka, Curtis; Woyczynski, Wojbor A; Lerner, Alan J

    2016-01-01

    Objective: To study the dynamics of clustering semantic fluency responses and switching between clusters. Methods: We conducted a cross-sectional study of participants (N = 60) in a study of patient reported outcomes who were given the Saint Louis University Mental Status test. Sixty-second animal naming tests were scored for the timing of responses as well as the clustering of responses into semantic categories. Time scores were detrended to correct for exponential exhaustion and normalize the time scale across individuals. Results: Grouped by number of responses given, low performers (LP; Carter et al., 2012) switched between clusters fewer times than medium performers (MP) and high performers (HP). Prior to detrending, LP showed increased intracluster response times when compared to the other groups, but no differences were shown in intercluster response times. After detrending, however, the difference in intracluster response times disappeared and LP showed significantly faster detrended intercluster response times compared to both MP and HP. Conclusion: Prior to detrending, slower intracluster response times appear to be driving poorer performance. When time scores are detrended, our findings suggest that LP participants have quicker intercluster response times but exhaust more quickly as well. Detrending can help describe the interplay between the structure-loss and retrieval-slowing models of declining semantic fluency by isolating the component mechanisms involved in each.

  11. Detrending Changes the Temporal Dynamics of a Semantic Fluency Task

    Directory of Open Access Journals (Sweden)

    Steven Lenio

    2016-10-01

    Full Text Available Objective: To study the dynamics of clustering semantic fluency responses and switching between clusters. Methods: We conducted a cross-sectional study of participants (N=60 in a study of patient reported outcomes who were given the Saint Louis University Mental Status test. Sixty-second animal naming tests were scored for the timing of responses as well as the clustering of responses into semantic categories. Time scores were detrended to correct for exponential exhaustion and normalize the time scale across individuals. Results: Grouped by number of responses given, low performers (1 switched between clusters fewer times than medium performers (MP and high performers (HP. Prior to detrending, LP showed increased intracluster response times when compared to the other groups but no differences were shown in intercluster response times. After detrending, however, the difference in intracluster response times disappeared and LP showed significantly faster detrended intercluster response times compared to both MP and HP. Conclusion: Prior to detrending, slower intracluster response times appear to be driving poorer performance. When time scores are detrended, our findings suggest that LP participants have quicker intercluster response times but exhaust more quickly as well. Detrending can help describe the interplay between the structure-loss and retrieval-slowing models of declining semantic fluency by isolating the component mechanisms involved in each.

  12. 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....

  13. Multi-Robot Dynamic Task Allocation Using Modified Ant Colony System

    Science.gov (United States)

    Xu, Zhenzhen; Xia, Feng; Zhang, Xianchao

    This paper presents a dynamic task allocation algorithm for multiple robots to visit multiple targets. This algorithm is specifically designed for the environment where robots have dissimilar starting and ending locations. And the constraint of balancing the number of targets visited by each robot is considered. More importantly, this paper takes into account the dynamicity of multi-robot system and the obstacles in the environment. This problem is modeled as a constrained MTSP which can not be transformed to TSP and can not be solved by classical Ant Colony System (ACS). The Modified Ant Colony System (MACS) is presented to solve this problem and the unvisited targets are allocated to appropriate robots dynamically. The simulation results show that the output of the proposed algorithm can satisfy the constraints and dynamicity for the problem of multi-robot task allocation.

  14. Prediction of binaural speech intelligibility against noise in rooms.

    Science.gov (United States)

    Lavandier, Mathieu; Culling, John F

    2010-01-01

    In the presence of competing speech or noise, reverberation degrades speech intelligibility not only by its direct effect on the target but also by affecting the interferer. Two experiments were designed to validate a method for predicting the loss of intelligibility associated with this latter effect. Speech reception thresholds were measured under headphones, using spatially separated target sentences and speech-shaped noise interferers simulated in virtual rooms. To investigate the effect of reverberation on the interferer unambiguously, the target was always anechoic. The interferer was placed in rooms with different sizes and absorptions, and at different distances and azimuths from the listener. The interaural coherence of the interferer did not fully predict the effect of reverberation. The azimuth separation of the sources and the coloration introduced by the room also had to be taken into account. The binaural effects were modeled by computing the binaural masking level differences in the studied configurations, the monaural effects were predicted from the excitation pattern of the noises, and speech intelligibility index weightings were applied to both. These parameters were all calculated from the room impulse responses convolved with noise. A 0.95-0.97 correlation was obtained between the speech reception thresholds and their predicted value.

  15. 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.

  16. 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...... and right binaural signals is used as a feature for this method. In addition, an extended set of additional statistical features that can improve distance detection is extracted from an auditory front-end which models the peripheral processing of the human auditory system. The method incorporates the above...

  17. Framing of task performance strategies: effects on performance in a multiattribute dynamic decision making environment.

    Science.gov (United States)

    Nygren, T E

    1997-09-01

    It is well documented that the way a static choice task is "framed" can dramatically alter choice behavior, often leading to observable preference reversals. This framing effect appears to result from perceived changes in the nature or location of a person's initial reference point, but it is not clear how framing effects might generalize to performance on dynamic decision making tasks that are characterized by high workload, time constraints, risk, or stress. A study was conducted to examine the hypothesis that framing can introduce affective components to the decision making process and can influence, either favorably (positive frame) or adversely (negative frame), the implementation and use of decision making strategies in dynamic high-workload environments. Results indicated that negative frame participants were significantly impaired in developing and employing a simple optimal decision strategy relative to a positive frame group. Discussion focuses on implications of these results for models of dynamic decision making.

  18. Prioritized motion-force control of constrained fully-actuated robots: "Task Space Inverse Dynamics"

    OpenAIRE

    Del Prete, Andrea; Nori, Francesco; Metta, Giorgio; Natale, Lorenzo

    2014-01-01

    We present a new framework for prioritized multi-task motion-force control of fully-actuated robots. This work is established on a careful review and comparison of the state of the art. Some control frameworks are not optimal, that is they do not find the optimal solution for the secondary tasks. Other frameworks are optimal, but they tackle the control problem at kinematic level, hence they neglect the robot dynamics and they do not allow for force control. Still other frameworks are optimal...

  19. 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. 

  20. 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.

  1. 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.

  2. Task and Context Sensitive Gripper Design Learning Using Dynamic Grasp Simulation

    DEFF Research Database (Denmark)

    Wolniakowski, Adam; Miatliuk, Konstantsin; Gosiewski, Z.

    2017-01-01

    given a CAD model of an object and a task description. These quality indices are then used to learn task-specific finger designs based on dynamic simulation. We demonstrate our gripper optimization on a parallel finger type gripper described by twelve parameters. We furthermore present a parametrization...... for different task contexts. We provide a qualitative evaluation of the obtained results based on existing design guidelines and our engineering experience. In addition, we show that with our method we achieve superior alignment properties compared to a naive approach with a cutout based on the “inverse...... of an object”. Furthermore, we provide an experimental evaluation of our proposed method by verifying the simulated grasp outcomes through a real-world experiment....

  3. Characterizing the monaural and binaural processes underlying reflection masking

    DEFF Research Database (Denmark)

    Buchholz, Jörg

    2007-01-01

    Reflection masked thresholds (RMTs) for the simple scenario of a test reflection masked by the direct sound (200 ms long broadband noise) were measured as a function of reflection delay for diotic and dichotic stimulus presentations. In order to discriminate between contributions to reflection...... masking from simultaneous versus forward masking, the simultaneous RMT was measured in addition to the traditional RMT. Simultaneous RM was realized by truncating the offset of the test reflection such that the test reflection and the direct sound had a common offset. By comparing the experimental results...... for the two RMTs, it is shown that forward masking effects only have a significant effect on reflection masking for delays above 7–10 ms. Moreover, binaural mechanisms were revealed which deteriorate auditory detection of test reflections for delays below 7–10 ms and enhance detection for larger delays...

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    interfering the individual's hearing and doing. In this work we propose a strategy for the recording of binaural audio with minimal hearing interference, and for transforming these recordings to blocked-entrance versions that are more suitable for analysis and reproduction of binaural audio in a more general...... 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....

  5. 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.

  6. Dynamic task scheduling algorithm with load balancing for heterogeneous computing system

    Directory of Open Access Journals (Sweden)

    Doaa M. Abdelkader

    2012-07-01

    Full Text Available In parallel computation, the scheduling and mapping tasks is considered the most critical problem which needs High Performance Computing (HPC to solve it by breaking the problem into subtasks and working on those subtasks at the same time. The application sub tasks are assigned to underline machines and ordered for execution according to its proceeding to grantee efficient use of available resources such as minimize execution time and satisfy load balance between processors of the underline machine. The underline infrastructure may be homogeneous or heterogeneous. Homogeneous infrastructure could use the same machines power and performance. While heterogeneous infrastructure include machines differ in its performance, speed, and interconnection. According to work in this paper a new dynamic task scheduling algorithm for Heterogeneous called a Clustering Based HEFT with Duplication (CBHD have been developed. The CBHD algorithm is considered an amalgamation between the most two important task scheduling in Heterogeneous machine, The Heterogeneous Earliest Finish Time (HEFT and the Triplet Clustering algorithms. In the CBHD algorithm the duplication is required to improve the performance of algorithm. A comparative study among the developed CBHD, the HEFT, and the Triplet Cluster algorithms has been done. According to the comparative results, it is found that the developed CBHD algorithm satisfies better execution time than both HEFT algorithm and Triplet Cluster algorithm, and in the same time, it achieves the load balancing which considered one of the main performance factors in the dynamic environment.

  7. Dynamic task allocation in multi-hop multimedia wireless sensor networks with low mobility.

    Science.gov (United States)

    Jin, Yichao; Vural, Serdar; Gluhak, Alexander; Moessner, Klaus

    2013-10-16

    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.

  8. 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.

  9. Learning Effects on Strategy Selection in a Dynamic Task Environment as a Function of Time Pressure

    Science.gov (United States)

    1994-06-01

    MANAGEMENT UI1TREKSEL Previous research on strategy selection in dynamic task environments indicated that subjects preferred to request information first...I febwari 1994 is de naam Instituut voor Zintuigfysiologie TNO gewijzigd in TNO Technische Menskunde. 2 CONTENTS Page SUMMARY 3 SAMENVAITING 4 I...waarin men gebruik maakt van de continue feedback over de toestand van het systeem . Proefpersonen moesten het veranderende conditieniveau van een atleet

  10. Some comparisons of binaural measurements made with different dummy heads and stereo microphone techniques

    Science.gov (United States)

    Mapp, Peter A.

    2004-10-01

    Binaural measurements have been made in a number of acoustic environments, and the results from different binaural heads and stereo microphones are compared. The object of the study was not only to establish what practical differences occurred between the various head formats, but also to see if a stereo microphone or pseudohead could be used for making auditorium binaural measurements. Five measurement platforms were employed. These included two binaural dummy heads, binaural in-ear probe microphones, an SAAS pseudohead stereo microphone and a M-S (midside) stereo microphone. In the latter case, three different midside ratios were employed and compared. The measurements were made in a reverberant recital hall (2.5-s RT) and small acoustically treated listening room (RT 0.2 s). Whereas relatively minor differences were found to occur between the heads, significant differences were found to occur with the stereo microphones. It is concluded that while useful information can be obtained from a stereo microphone, it is far from being the same as binaural.

  11. 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.

  12. Dynamic Resource Management for Parallel Tasks in an Oversubscribed Energy-Constrained Heterogeneous Environment

    Energy Technology Data Exchange (ETDEWEB)

    Imam, Neena [ORNL; Koenig, Gregory A [ORNL; Machovec, Dylan [Colorado State University, Fort Collins; Khemka, Bhavesh [Colorado State University, Fort Collins; Pasricha, Sudeep [Colorado State University; Maciejewski, Anthony A [Colorado State University, Fort Collins; Siegel, Howard [Colorado State University, Fort Collins; Wright, Michael [Department of Defense; Hilton, Marcia [Department of Defense; Rambharos, Rejendra [Department of Defense

    2016-01-01

    Abstract: The worth of completing parallel tasks is modeled using utility functions, which monotonically-decrease with time and represent the importance and urgency of a task. These functions define the utility earned by a task at the time of its completion. The performance of such a system is measured as the total utility earned by all completed tasks over some interval of time (e.g., 24 hours). To maximize system performance when scheduling dynamically arriving parallel tasks onto a high performance computing (HPC) system that is oversubscribed and energy-constrained, we have designed, analyzed, and compared different heuristic techniques. Four utility-aware heuristics (i.e., Max Utility, Max Utility-per-Time, Max Utility-per-Resource, and Max Utility-per-Energy), three FCFS-based heuristics (Conservative Backfilling, EASY Backfilling, and FCFS with Multiple Queues), and a Random heuristic were examined in this study. A technique that is often used with the FCFS-based heuristics is the concept of a permanent reservation. We compare the performance of permanent reservations with temporary place-holders to demonstrate the advantages that place-holders can provide. We also present a novel energy filtering technique that constrains the maximum energy-per-resource used by each task. We conducted a simulation study to evaluate the performance of these heuristics and techniques in an energy-constrained oversubscribed HPC environment. With place-holders, energy filtering, and dropping tasks with low potential utility, our utility-aware heuristics are able to significantly outperform the existing FCFS-based techniques.

  13. 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.

  14. 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.

  15. Grcarma: A fully automated task-oriented interface for the analysis of molecular dynamics trajectories.

    Science.gov (United States)

    Koukos, Panagiotis I; Glykos, Nicholas M

    2013-10-05

    We report the availability of grcarma, a program encoding for a fully automated set of tasks aiming to simplify the analysis of molecular dynamics trajectories of biological macromolecules. It is a cross-platform, Perl/Tk-based front-end to the program carma and is designed to facilitate the needs of the novice as well as those of the expert user, while at the same time maintaining a user-friendly and intuitive design. Particular emphasis was given to the automation of several tedious tasks, such as extraction of clusters of structures based on dihedral and Cartesian principal component analysis, secondary structure analysis, calculation and display of root-meansquare deviation (RMSD) matrices, calculation of entropy, calculation and analysis of variance–covariance matrices, calculation of the fraction of native contacts, etc. The program is free-open source software available immediately for download.

  16. Dynamic and opposing adjustment of movement cancellation and generation in an oculomotor countermanding task.

    Science.gov (United States)

    Corneil, Brian D; Cheng, Joshua C; Goonetilleke, Samanthi C

    2013-06-12

    Adaptive adjustments of strategies help optimize behavior in a dynamic and uncertain world. Previous studies in the countermanding (or stop-signal) paradigm have detailed how reaction times (RTs) change with trial sequence, demonstrating adaptive control of movement generation. Comparatively little is known about the adaptive control of movement cancellation in the countermanding task, mainly because movement cancellation implies the absence of an outcome and estimates of movement cancellation require hundreds of trials. Here, we exploit a within-trial proxy of movement cancellation based on recordings of neck muscle activity while human subjects attempted to cancel large eye-head gaze shifts. On a subset of successfully cancelled trials where gaze remains stable, small head-only movements to the target are actively braked by a pulse of antagonist neck muscle activity. The timing of such antagonist muscle recruitment relative to the stop signal, termed the "antagonist latency," tended to decrease or increase after trials with or without a stop-signal, respectively. Over multiple time scales, fluctuations in the antagonist latency tended to be the mirror opposite of those occurring contemporaneously with RTs. These results provide new insights into the adaptive control of movement cancellation at an unprecedented resolution, suggesting it can be as prone to dynamic adjustment as movement generation. Adaptive control in the countermanding task appears to be governed by a dynamic balance between movement cancellation and generation: shifting the balance in favor of movement cancellation slows movement generation, whereas shifting the balance in favor of movement generation slows movement cancellation.

  17. 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

  18. 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.

  19. 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.

  20. Paradoxical response to an emotional task: trait characteristics and heart-rate dynamics.

    Science.gov (United States)

    Balocchi, Rita; Varanini, Maurizio; Paoletti, Giulia; Mecacci, Giulio; Santarcangelo, Enrica L

    2015-01-01

    The present study evaluated the heart-rate dynamics of subjects reporting decreased (responders) or paradoxically increased relaxation (nonresponders) at the end of a threatening movie. Heart-rate dynamics were characterized by indices extracted through recurrence quantification analysis (RQA) and detrended fluctuation analysis (DFA). These indices were studied as a function of a few individual characteristics: hypnotizability, gender, absorption, anxiety, and the activity of the behavioral inhibition and activation systems (BIS/BAS). Results showed that (a) the subjective experience of responsiveness is associated with the activity of the behavioral inhibition system and (b) a few RQA and DFA indices are able to capture the influence of cognitive-emotional traits, including hypnotizability, on the responsiveness to the threatening task.

  1. The impacts of hypnotic susceptibility on chaotic dynamics of EEG signals during standard tasks of Waterloo-Stanford Group Scale.

    Science.gov (United States)

    Yargholi, Elahe'; Nasrabadi, Ali Motie

    2013-05-01

    Chaotic features of hypnotic EEG (electroencephalograph), recorded during standard tasks of Waterloo-Stanford Group Scale of hypnotic susceptibility (WSGS), were used to investigate the underlying dynamic of tasks and analyse the effect of hypnotic depth and concentration on EEG signals. Results demonstrate: (1) More efficiency of Higuchi dimension in comparison with Correlation dimension to distinguish subjects from different hypnotizable groups, (2) Channels with significantly different chaotic features among people from various hypnotizability levels in tasks, (3) High level of consistency among discriminating channels of tasks with function of brain's lobes, (4) Most affectability of medium hypnotizable subjects and (5) Rise in fractal dimensions due to increase in hypnosis depth.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. Tracking EEG changes in response to alpha and beta binaural beats.

    Science.gov (United States)

    Vernon, D; Peryer, G; Louch, J; Shaw, M

    2014-07-01

    A binaural beat can be produced by presenting two tones of a differing frequency, one to each ear. Such auditory stimulation has been suggested to influence behaviour and cognition via the process of cortical entrainment. However, research so far has only shown the frequency following responses in the traditional EEG frequency ranges of delta, theta and gamma. Hence a primary aim of this research was to ascertain whether it would be possible to produce clear changes in the EEG in either the alpha or beta frequency ranges. Such changes, if possible, would have a number of important implications as well as potential applications. A secondary goal was to track any observable changes in the EEG throughout the entrainment epoch to gain some insight into the nature of the entrainment effects on any changes in an effort to identify more effective entrainment regimes. Twenty two healthy participants were recruited and randomly allocated to one of two groups, each of which was exposed to a distinct binaural beat frequency for ten 1-minute epochs. The first group listened to an alpha binaural beat of 10 Hz and the second to a beta binaural beat of 20 Hz. EEG was recorded from the left and right temporal regions during pre-exposure baselines, stimulus exposure epochs and post-exposure baselines. Analysis of changes in broad-band and narrow-band amplitudes, and frequency showed no effect of binaural beat frequency eliciting a frequency following effect in the EEG. Possible mediating factors are discussed and a number of recommendations are made regarding future studies, exploring entrainment effects from a binaural beat presentation.

  7. The Binaural Interaction Component in Barn Owl (Tyto alba) Presents few Differences to Mammalian Data.

    Science.gov (United States)

    Palanca-Castan, Nicolas; Laumen, Geneviève; Reed, Darrin; Köppl, Christine

    2016-12-01

    The auditory brainstem response (ABR) is an evoked potential that reflects the responses to sound by brainstem neural centers. The binaural interaction component (BIC) is obtained by subtracting the sum of the monaural ABR responses from the binaural response. Its latency and amplitude change in response to variations in binaural cues. The BIC is thus thought to reflect the activity of binaural nuclei and is used to non-invasively test binaural processing. However, any conclusions are limited by a lack of knowledge of the relevant processes at the level of individual neurons. The aim of this study was to characterize the ABR and BIC in the barn owl, an animal where the ITD-processing neural circuits are known in great detail. We recorded ABR responses to chirps and to 1 and 4 kHz tones from anesthetized barn owls. General characteristics of the barn owl ABR were similar to those observed in other bird species. The most prominent peak of the BIC was associated with nucleus laminaris and is thus likely to reflect the known processes of ITD computation in this nucleus. However, the properties of the BIC were very similar to previously published mammalian data and did not reveal any specific diagnostic features. For example, the polarity of the BIC was negative, which indicates a smaller response to binaural stimulation than predicted by the sum of monaural responses. This is contrary to previous predictions for an excitatory-excitatory system such as nucleus laminaris. Similarly, the change in BIC latency with varying ITD was not distinguishable from mammalian data. Contrary to previous predictions, this behavior appears unrelated to the known underlying neural delay-line circuitry. In conclusion, the generation of the BIC is currently inadequately understood and common assumptions about the BIC need to be reconsidered when interpreting such measurements.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. Anodal Transcranial Direct Current Stimulation Does Not Facilitate Dynamic Balance Task Learning in Healthy Old Adults

    Science.gov (United States)

    Kaminski, Elisabeth; Hoff, Maike; Rjosk, Viola; Steele, Christopher J.; Gundlach, Christopher; Sehm, Bernhard; Villringer, Arno; Ragert, Patrick

    2017-01-01

    Older adults frequently experience a decrease in balance control that leads to increased numbers of falls, injuries and hospitalization. Therefore, evaluating older adults’ ability to maintain balance and examining new approaches to counteract age-related decline in balance control is of great importance for fall prevention and healthy aging. Non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) have been shown to beneficially influence motor behavior and motor learning. In the present study, we investigated the influence of tDCS applied over the leg area of the primary motor cortex (M1) on balance task learning of healthy elderly in a dynamic balance task (DBT). In total, 30 older adults were enrolled in a cross-sectional, randomized design including two consecutive DBT training sessions. Only during the first DBT session, either 20 min of anodal tDCS (a-tDCS) or sham tDCS (s-tDCS) were applied and learning improvement was compared between the two groups. Our data showed that both groups successfully learned to perform the DBT on both training sessions. Interestingly, between-group analyses revealed no difference between the a-tDCS and the s-tDCS group regarding their level of task learning. These results indicate that the concurrent application of tDCS over M1 leg area did not elicit DBT learning enhancement in our study cohort. However, a regression analysis revealed that DBT performance can be predicted by the kinematic profile of the movement, a finding that may provide new insights for individualized approaches of treating balance and gait disorders. PMID:28197085

  13. Dynamic NMDAR-mediated properties of place cells during the object place memory task.

    Science.gov (United States)

    Faust, Thomas W; Robbiati, Sergio; Huerta, Tomás S; Huerta, Patricio T

    2013-01-01

    N-methyl-D-aspartate receptors (NMDAR) in the hippocampus participate in encoding and recalling the location of objects in the environment, but the ensemble mechanisms by which NMDARs mediate these processes have not been completely elucidated. To address this issue, we examined the firing patterns of place cells in the dorsal CA1 area of the hippocampus of mice (n = 7) that performed an object place memory (OPM) task, consisting of familiarization (T1), sample (T2), and choice (T3) trials, after systemic injection of 3-[(±)2-carboxypiperazin-4yl]propyl-1-phosphate (CPP), a specific NMDAR antagonist. Place cell properties under CPP (CPP-PCs) were compared to those after control saline injection (SAL-PCs) in the same mice. We analyzed place cells across the OPM task to determine whether they signaled the introduction or movement of objects by NMDAR-mediated changes of their spatial coding. On T2, when two objects were first introduced to a familiar chamber, CPP-PCs and SAL-PCs showed stable, vanishing or moving place fields in addition to changes in spatial information (SI). These metrics were comparable between groups. Remarkably, previously inactive CPP-PCs (with place fields emerging de novo on T2) had significantly weaker SI increases than SAL-PCs. On T3, when one object was moved, CPP-PCs showed reduced center-of-mass (COM) shift of their place fields. Indeed, a subset of SAL-PCs with large COM shifts (>7 cm) was largely absent in the CPP condition. Notably, for SAL-PCs that exhibited COM shifts, those initially close to the moving object followed the trajectory of the object, whereas those far from the object did the opposite. Our results strongly suggest that the SI changes and COM shifts of place fields that occur during the OPM task reflect key dynamic properties that are mediated by NMDARs and might be responsible for binding object identity with location.

  14. Dynamic NMDAR-mediated properties of place cells during the object place memory task

    Directory of Open Access Journals (Sweden)

    Thomas William Faust

    2013-12-01

    Full Text Available N-methyl-D-aspartate receptors (NMDAR in the hippocampus participate in encoding and recalling the location of objects in the environment, but the ensemble mechanisms by which NMDARs mediate these processes have not been completely elucidated. To address this issue, we examined the firing patterns of place cells in the dorsal CA1 area of the hippocampus of mice (n = 7 that performed an object place memory (OPM task, consisting of familiarization (T1, sample (T2 and choice (T3 trials, after systemic injection of 3-((±2-carboxypiperazin-4ylpropyl-1-phosphate (CPP, a specific NMDAR antagonist. Place cell properties under CPP (CPP–PCs were compared to those after control saline injection (SAL–PCs in the same mice. We analyzed place cells across the OPM task to determine whether they signaled the introduction or movement of objects by NMDAR-mediated changes of their spatial coding. On T2, when two objects were first introduced to a familiar chamber, CPP–PCs and SAL–PCs showed stable, vanishing or moving place fields in addition to changes in spatial information (SI. These metrics were comparable between groups. Remarkably, previously inactive CPP–PCs (with place fields emerging de novo on T2 had significantly weaker SI increases than SAL–PCs. On T3, when one object was moved, CPP–PCs showed reduced center-of-mass (COM shift of their place fields. Indeed, a subset of SAL–PCs with large COM shifts (>7 cm was largely absent in the CPP condition. Notably, for SAL–PCs that exhibited COM shifts, those initially close to the moving object followed the trajectory of the object, whereas those far from the object did the opposite. Our results strongly suggest that the SI changes and COM shifts of place fields that occur during the OPM task reflect key dynamic properties that are mediated by NMDARs and might be responsible for binding object identity with location.

  15. 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.

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

    Science.gov (United States)

    Li, Chia-Tzu; Lai, Wen-Sung; Liu, Chih-Min; Hsu, Yung-Fong

    2014-01-01

    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 = 0.09, trending toward 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.

  17. Anodal Transcranial Direct Current Stimulation Does Not Facilitate Dynamic Balance Task Learning in Healthy Old Adults.

    Science.gov (United States)

    Kaminski, Elisabeth; Hoff, Maike; Rjosk, Viola; Steele, Christopher J; Gundlach, Christopher; Sehm, Bernhard; Villringer, Arno; Ragert, Patrick

    2017-01-01

    Older adults frequently experience a decrease in balance control that leads to increased numbers of falls, injuries and hospitalization. Therefore, evaluating older adults' ability to maintain balance and examining new approaches to counteract age-related decline in balance control is of great importance for fall prevention and healthy aging. Non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) have been shown to beneficially influence motor behavior and motor learning. In the present study, we investigated the influence of tDCS applied over the leg area of the primary motor cortex (M1) on balance task learning of healthy elderly in a dynamic balance task (DBT). In total, 30 older adults were enrolled in a cross-sectional, randomized design including two consecutive DBT training sessions. Only during the first DBT session, either 20 min of anodal tDCS (a-tDCS) or sham tDCS (s-tDCS) were applied and learning improvement was compared between the two groups. Our data showed that both groups successfully learned to perform the DBT on both training sessions. Interestingly, between-group analyses revealed no difference between the a-tDCS and the s-tDCS group regarding their level of task learning. These results indicate that the concurrent application of tDCS over M1 leg area did not elicit DBT learning enhancement in our study cohort. However, a regression analysis revealed that DBT performance can be predicted by the kinematic profile of the movement, a finding that may provide new insights for individualized approaches of treating balance and gait disorders.

  18. 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....

  19. The role of segmental mass and moment of inertia in dynamic-contact task construction.

    Science.gov (United States)

    Brown, Nicholas A T; Jensen, Jody L

    2006-07-01

    The authors examined whether differences between children and adults in the application of muscle forces during a dynamic-contact task (cycling) can be attributed to children's relatively lower segmental mass and moment of inertia. They examined pedal-force construction as adults and younger and older children (n = 7 in each group), with and without mass added to their limbs, pedaled an appropriately scaled bicycle ergometer. When mass was added to their limbs, children adjusted muscular forces on the pedal in a way that began to approach the pattern demonstrated by adults. Because age, neuromotor maturation, and motor experience were held constant, it seems plausible that by 6 to 8 years of age, and perhaps younger, physical size and growth limit children's production of adult-like muscle forces on the pedal.

  20. 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

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

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten

    . The results from two stimulus configurations, namely Huggins’ pitch stimuli and pure tones presented in diotic white noise, were compared. In addition to the pitch detection experiment, measures of frequency selectivity, fine structure and envelope processing, binaural interaction, and cognitive abilities...

  2. 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...

  3. 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

  4. The role of reverberation-related binaural cues in the externalization of speech

    DEFF Research Database (Denmark)

    Catic, Jasmina; Santurette, Sébastien; Dau, Torsten

    2015-01-01

    for the externalization of a lateral sound source. In contrast, for a frontal source, an increased amount of binaural cues from reflections was required in order to obtain well externalized sound images. It was demonstrated that the interaction between the interaural cues of the direct sound and the reverberation...

  5. 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...

  6. 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 succe...

  7. A Binaural Grouping Model for Predicting Speech Intelligibility in Multitalker Environments

    Directory of Open Access Journals (Sweden)

    Jing Mi

    2016-09-01

    Full Text Available Spatially separating speech maskers from target speech often leads to a large intelligibility improvement. Modeling this phenomenon has long been of interest to binaural-hearing researchers for uncovering brain mechanisms and for improving signal-processing algorithms in hearing-assistive devices. Much of the previous binaural modeling work focused on the unmasking enabled by binaural cues at the periphery, and little quantitative modeling has been directed toward the grouping or source-separation benefits of binaural processing. In this article, we propose a binaural model that focuses on grouping, specifically on the selection of time-frequency units that are dominated by signals from the direction of the target. The proposed model uses Equalization-Cancellation (EC processing with a binary decision rule to estimate a time-frequency binary mask. EC processing is carried out to cancel the target signal and the energy change between the EC input and output is used as a feature that reflects target dominance in each time-frequency unit. The processing in the proposed model requires little computational resources and is straightforward to implement. In combination with the Coherence-based Speech Intelligibility Index, the model is applied to predict the speech intelligibility data measured by Marrone et al. The predicted speech reception threshold matches the pattern of the measured data well, even though the predicted intelligibility improvements relative to the colocated condition are larger than some of the measured data, which may reflect the lack of internal noise in this initial version of the model.

  8. A Binaural Grouping Model for Predicting Speech Intelligibility in Multitalker Environments.

    Science.gov (United States)

    Mi, Jing; Colburn, H Steven

    2016-10-03

    Spatially separating speech maskers from target speech often leads to a large intelligibility improvement. Modeling this phenomenon has long been of interest to binaural-hearing researchers for uncovering brain mechanisms and for improving signal-processing algorithms in hearing-assistive devices. Much of the previous binaural modeling work focused on the unmasking enabled by binaural cues at the periphery, and little quantitative modeling has been directed toward the grouping or source-separation benefits of binaural processing. In this article, we propose a binaural model that focuses on grouping, specifically on the selection of time-frequency units that are dominated by signals from the direction of the target. The proposed model uses Equalization-Cancellation (EC) processing with a binary decision rule to estimate a time-frequency binary mask. EC processing is carried out to cancel the target signal and the energy change between the EC input and output is used as a feature that reflects target dominance in each time-frequency unit. The processing in the proposed model requires little computational resources and is straightforward to implement. In combination with the Coherence-based Speech Intelligibility Index, the model is applied to predict the speech intelligibility data measured by Marrone et al. The predicted speech reception threshold matches the pattern of the measured data well, even though the predicted intelligibility improvements relative to the colocated condition are larger than some of the measured data, which may reflect the lack of internal noise in this initial version of the model.

  9. Effect of dual task type on gait and dynamic stability during stair negotiation at different inclinations

    NARCIS (Netherlands)

    Madehkhaksar, F.; Egges, J.

    2016-01-01

    Stair gait is a common daily activity with great potential risk for falls. Stairs have varying inclinations and people may perform other tasks concurrently with stair gait. This study investigated dual-task interference in the context of complex gait tasks, such as stair gait at different inclinatio

  10. 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…

  11. Task Repetition and Its Impact on EFL Children's Negotiation of Meaning Strategies and Pair Dynamics: An Exploratory Study

    Science.gov (United States)

    del Pilar García Mayo, Maria; Imaz Agirre, Ainara

    2016-01-01

    Little research has been carried out on the effect of task repetition on young learners' negotiation of meaning (NoM) strategies and on pair dynamics. The present study aims to fill this gap by analysing the interaction of 60 dyads of third- and fourth-year primary English as a foreign language learners (8-9, 9-10 years old, respectively) while…

  12. 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.

  13. Integrated operational control and dynamic task allocation of unattended distributed sensor systems

    Science.gov (United States)

    Talukder, Ashit

    2009-05-01

    Unattended autonomous systems of the future will involve groups of static and mobile sensors functioning in coordination to achieve overall task objectives. Such systems can be viewed as wirelessly networked unmanned heterogeneous sensor networks. We discuss a distributed heterogeneous sensing system with static sensors and mobile robots with novel control optimization algorithms for dynamic adaptation, coordinated control and end to end resource management of all sensors in response to detected events to achieve overall system goals and objectives. Our system is designed for a host of applications, such as unmediated data monitoring and record keeping of the environment, battlefield monitoring using integrated ground, ocean and air sensors, and reactive operation to threats or changing conditions, and homeland security or border/road surveillance systems where unmanned vehicles can be deployed autonomously in response to detected events. Results for large area coastal monitoring are presented. Offline results using actual modeled data from in-situ sensory measurements demonstrate how the sensor parameters can be adapted to maximize observability of a freshwater plume while ensuring that individual system components operate within their physical limitations.1 2

  14. A novel energy-aware multi-task dynamic mapping heuristic of NoC-based MPSoCs

    Science.gov (United States)

    Zhao, Xibin; Gu, Ming

    2013-05-01

    Task mapping is an important issue in network-on-chip (NoC)-based multiprocessor systems-on-chips (MPSoCs) design. The dynamic characteristic of application execution enforces the use of dynamic task mapping. In this article, a hybrid energy-aware dynamic mapping strategy is proposed. The strategy consists of an off-line part and an on-line part. In the off-line part, optimisation tools are used to extract information that helps to reduce the energy consumption in the on-line mapping, while the on-line mapping heuristic makes use of the information. Experimental result shows that the energy consumption is reduced by 21%, on average, compared to the best neighbour heuristic.

  15. Studies on bilateral cochlear implants at the University of Wisconsin's Binaural Hearing and Speech Laboratory.

    Science.gov (United States)

    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

    2012-06-01

    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 article we describe the benefits from BiCIs compared with a single cochlear implant (CI), focusing on measures of spatial hearing and speech understanding in noise. We highlight the fact that in BiCI listening the devices in the two ears are not coordinated; thus binaural spatial cues that are available to NH listeners are not available to BiCI users. Through the use of research processors that carefully control the stimulus delivered to each electrode in each ear, we are able to preserve binaural cues and deliver them with fidelity to BiCI users. Results from those studies are discussed as well, with a focus on the effect of age at onset of deafness and plasticity of binaural sensitivity. Our work with children has expanded both in number of subjects tested and age range included. We have now tested dozens of children ranging in age from 2 to 14 yr. Our findings suggest that spatial hearing abilities emerge with bilateral experience. While we originally focused on studying performance in free field, where real world listening experiments are conducted, more recently we have begun to conduct studies under carefully controlled binaural stimulation conditions with children as well. We have also studied language acquisition and speech perception and production in young CI users. Finally, a running theme of this research program is the systematic investigation of the numerous factors that contribute to spatial and binaural hearing in BiCI users. By using CI simulations (with vocoders) and studying NH listeners under degraded listening conditions, we are able to tease apart limitations due to the hardware/software of the CI

  16. Behavioral manifestations of audiometrically-defined "slight" or "hidden" hearing loss revealed by measures of binaural detection.

    Science.gov (United States)

    Bernstein, Leslie R; Trahiotis, Constantine

    2016-11-01

    This study assessed whether audiometrically-defined "slight" or "hidden" hearing losses might be associated with degradations in binaural processing as measured in binaural detection experiments employing interaurally delayed signals and maskers. Thirty-one listeners participated, all having no greater than slight hearing losses (i.e., no thresholds greater than 25 dB HL). Across the 31 listeners and consistent with the findings of Bernstein and Trahiotis [(2015). J. Acoust. Soc. Am. 138, EL474-EL479] binaural detection thresholds at 500 Hz and 4 kHz increased with increasing magnitude of interaural delay, suggesting a loss of precision of coding with magnitude of interaural delay. Binaural detection thresholds were consistently found to be elevated for listeners whose absolute thresholds at 4 kHz exceeded 7.5 dB HL. No such elevations were observed in conditions having no binaural cues available to aid detection (i.e., "monaural" conditions). Partitioning and analyses of the data revealed that those elevated thresholds (1) were more attributable to hearing level than to age and (2) result from increased levels of internal noise. The data suggest that listeners whose high-frequency monaural hearing status would be classified audiometrically as being normal or "slight loss" may exhibit substantial and perceptually meaningful losses of binaural processing.

  17. 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.

  18. 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.

  19. 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

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

    Science.gov (United States)

    Osada, Takahiro; Adachi, Yusuke; Miyamoto, Kentaro; Jimura, Koji; Setsuie, Rieko; Miyashita, Yasushi

    2015-06-01

    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 static anatomical

  1. Intense and specialized dendritic localization of the fragile X mental retardation protein in binaural brainstem neurons: a comparative study in the alligator, chicken, gerbil, and human.

    Science.gov (United States)

    Wang, Yuan; Sakano, Hitomi; Beebe, Karisa; Brown, Maile R; de Laat, Rian; Bothwell, Mark; Kulesza, Randy J; Rubel, Edwin W

    2014-06-15

    Neuronal dendrites are structurally and functionally dynamic in response to changes in afferent activity. The fragile X mental retardation protein (FMRP) is an mRNA binding protein that regulates activity-dependent protein synthesis and morphological dynamics of dendrites. Loss and abnormal expression of FMRP occur in fragile X syndrome (FXS) and some forms of autism spectrum disorders. To provide further understanding of how FMRP signaling regulates dendritic dynamics, we examined dendritic expression and localization of FMRP in the reptilian and avian nucleus laminaris (NL) and its mammalian analogue, the medial superior olive (MSO), in rodents and humans. NL/MSO neurons are specialized for temporal processing of low-frequency sounds for binaural hearing, which is impaired in FXS. Protein BLAST analyses first demonstrate that the FMRP amino acid sequences in the alligator and chicken are highly similar to human FMRP with identical mRNA-binding and phosphorylation sites, suggesting that FMRP functions similarly across vertebrates. Immunocytochemistry further reveals that NL/MSO neurons have very high levels of dendritic FMRP in low-frequency hearing vertebrates including alligator, chicken, gerbil, and human. Remarkably, dendritic FMRP in NL/MSO neurons often accumulates at branch points and enlarged distal tips, loci known to be critical for branch-specific dendritic arbor dynamics. These observations support an important role for FMRP in regulating dendritic properties of binaural neurons that are essential for low-frequency sound localization and auditory scene segregation, and support the relevance of studying this regulation in nonhuman vertebrates that use low frequencies in order to further understand human auditory processing disorders.

  2. Dynamic proprioceptive target matching behavior in the upper limb: effects of speed, task difficulty and arm/hemisphere asymmetries.

    Science.gov (United States)

    Goble, Daniel J; Brown, Susan H

    2009-06-08

    Although proprioception consists of static (i.e. position) and dynamic (i.e. movement) components, most studies regarding the matching of proprioceptive targets have focused only on position. Further, these position-matching studies have recently indicated that proprioceptive ability is influenced by several factors including task difficulty and arm preference. The purpose of the present study, therefore, was to quantify the matching of dynamic proprioceptive target arm movements under different matching conditions. Using torque motor-driven manipulanda, 11 blindfolded, right-handed adults experienced triangular velocity profiles at 2 different peak speeds (30 degrees /s or 60 degrees /s) with the preferred and non-preferred elbow. Subjects then matched the dynamics of these target movements with either the same (ipsilateral remembered) or opposite (contralateral remembered) elbow. Matching errors were generally larger for the more difficult, contralateral remembered versus ipsilateral remembered task, and for greater target speed conditions. One arm difference was found indicating a non-preferred arm advantage for the matching of average target acceleration in the ipsilateral remembered condition. Overall, these results demonstrate that dynamic proprioceptive feedback-matching performance is influenced by several factors including peak speed, task difficulty and limb preference.

  3. Transition of COM-COP relative phase in a dynamic balance task.

    Science.gov (United States)

    Ko, Ji-Hyun; Challis, John H; Newell, Karl M

    2014-12-01

    The purpose of this study was to investigate whether the coordination between center of mass (COM) and center of pressure (COP) could be a candidate collective variable of a dynamical system that captures the organization of the multi-segmental whole body postural control system. We examined the transition of the COM-COP coordination pattern in a moving platform balance control paradigm. 10 young healthy adults stood on a moving surface of support that within a trial was sinusoidally translated in the anterior-posterior direction continuously scaling up and then down its frequency within the range from 0Hz to 3.0Hz. The COP was derived from a single force platform mounted on the moving surface of support. 4 angular joint motions (ankle, knee, hip, and neck) were measured by a 3D motion analysis system that also allowed COM to be derived. The COM-COP coordination changed from in-phase/anti-phase to anti-phase/in-phase at a certain frequency of the support surface, showed hysteresis as a function of the direction of frequency change and higher variability at the transition region. Conversely, the transition of the ankle-hip coordination consistently occurred at 0.3Hz across subjects with little between or within subject variability as a function of transition frequency and before the COM-COP transition. The findings provide evidence that: (1) the transition of the COM-COP coordination pattern is that of a non-equilibrium phase transition with critical fluctuations and hysteresis; and (2) that COM-COP coupling is a candidate collective variable of the multi-segmental whole body postural control system acting on a redundant postural task.

  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

    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.

  6. 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...

  7. 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.

  8. 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.

  9. Components representation of negative numbers: evidence from auditory stimuli detection and number classification tasks.

    Science.gov (United States)

    Kong, Feng; Zhao, Jingjing; You, Xuqun

    2012-01-01

    Past research suggested that negative numbers could be represented in terms of their components in the visual modality. The present study examined the processing of negative numbers in the auditory modality and whether it is affected by context. Experiment 1 employed a stimuli detection task where only negative numbers were presented binaurally. Experiment 2 employed the same task, but both positive and negative numbers were mixed as cues. A reverse attentional spatial-numerical association of response codes (SNARC) effect for negative numbers was obtained in these two experiments. Experiment 3 employed a number classification task where only negative numbers were presented binaurally. Experiment 4 employed the same task, but both positive and negative numbers were mixed. A reverse SNARC effect for negative numbers was obtained in these two experiments. These findings suggest that negative numbers in the auditory modality are generated from the set of positive numbers, thus supporting a components representation.

  10. 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.

  11. 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.

  12. A preliminary study of longitudinal differences in local dynamic stability between recently concussed and healthy athletes during single and dual-task gait.

    Science.gov (United States)

    Fino, Peter C

    2016-06-14

    Concussed individuals commonly exhibit locomotor deficits during dual-task gait that can last substantially longer than clinical signs and symptoms. Previous studies have examined traditional stability measures, but nonlinear stability may offer further information about the health of the motor control system post-concussion. For up to one year post-concussion, this study longitudinally examined the local dynamic stability of five concussed athletes and four matched healthy controls during single- and dual-task gait. Local dynamic stability (LDS) was estimated using short-term, finite-time maximum Lyapunov exponents calculated from tri-axial accelerometers placed on the trunk and head. No main effects of group or task were found for LDS or stride time variability, but significant group*task interactions were apparent for trunk stability and stride time variability. Concussed individuals exhibited decreased trunk LDS and increased stride time variability during dual-task walking compared to matched controls despite similar single-task stability and variability. These preliminary results reinforce previous reports that concussions persistently affect dual-task processes even when single-tasks may be unaffected. Furthermore, the decreased local dynamic stability during dual-task gait indicates the concussed group attenuated local disturbances less than their healthy teammates. The decreased dynamic stability during dual-task activities was present after the athletes were cleared for competition and may be a contributing factor in the higher rates of musculoskeletal injuries in athletes post-concussion.

  13. Design of an Adaptive Human-Machine System Based on Dynamical Pattern Recognition of Cognitive Task-Load

    Science.gov (United States)

    Zhang, Jianhua; Yin, Zhong; Wang, Rubin

    2017-01-01

    This paper developed a cognitive task-load (CTL) classification algorithm and allocation strategy to sustain the optimal operator CTL levels over time in safety-critical human-machine integrated systems. An adaptive human-machine system is designed based on a non-linear dynamic CTL classifier, which maps a set of electroencephalogram (EEG) and electrocardiogram (ECG) related features to a few CTL classes. The least-squares support vector machine (LSSVM) is used as dynamic pattern classifier. A series of electrophysiological and performance data acquisition experiments were performed on seven volunteer participants under a simulated process control task environment. The participant-specific dynamic LSSVM model is constructed to classify the instantaneous CTL into five classes at each time instant. The initial feature set, comprising 56 EEG and ECG related features, is reduced to a set of 12 salient features (including 11 EEG-related features) by using the locality preserving projection (LPP) technique. An overall correct classification rate of about 80% is achieved for the 5-class CTL classification problem. Then the predicted CTL is used to adaptively allocate the number of process control tasks between operator and computer-based controller. Simulation results showed that the overall performance of the human-machine system can be improved by using the adaptive automation strategy proposed. PMID:28367110

  14. 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...

  15. 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.

  16. 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.

  17. 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…

  18. 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

  19. LOAD ADAPTIVE DYNAMIC SCHEDULING OF TASKS WITH HARD DEADLINES USEFUL FOR INDUSTRIAL APPLICATIONS

    NARCIS (Netherlands)

    HALANG, WA

    1992-01-01

    All intrinsic properties of the earliest deadline task scheduling discipline are compiled and discussed in order to show that this is the most advantageous scheme at hand, characterised by efficiency and allowing predictable system behaviour. It is then pointed out how the method naturally extends t

  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.

  1. Paradoxical response to an emotional task: Trait characteristics and heart-rate dynamics

    NARCIS (Netherlands)

    Balocchia, R.; Varanini, M.; Paoletti, G.; Mecacci, G.; Santarcangelo, E.L.

    2015-01-01

    The present study evaluated the heart-rate dynamics of subjects reporting decreased (responders) or paradoxically increased relaxation (nonresponders) at the end of a threatening movie. Heart-rate dynamics were characterized by indices extracted through recurrence quantification analysis (RQA) and d

  2. Effects of using dynamic office chairs on posture and EMG in standardized office tasks

    NARCIS (Netherlands)

    Ellegast, R.; Hamburger, R.; Keller, K.; Krause, F.; Groenesteijn, L.; Vink, P.; Berger, H.

    2007-01-01

    In the paper a measuring system for the comparative posture and EMG analysis of office chairs is presented. With the system four specific dynamic office chairs that promote dynamic sitting and therefore aim to prevent musculoskeletal disorders (MSD), were analyzed in comparison to a reference chair

  3. Measuring Group Work Dynamics and Its Relation with L2 Learners' Task Motivation and Language Production

    Science.gov (United States)

    Poupore, Glen

    2016-01-01

    While learners of a second language (L2) are increasingly interacting in small groups as part of a communicative methodological paradigm, very few studies have investigated the social dynamics that occur in such groups. The aim of this study is to introduce a group work dynamic measuring instrument and to investigate the relationship between group…

  4. Hearing in a shoe-box : binaural source position and wall absorption estimation using virtually supervised learning

    OpenAIRE

    Kataria, Saurabh; Gaultier, Clément; Deleforge, Antoine

    2016-01-01

    This paper introduces a new framework for supervised sound source localization referred to as virtually-supervised learning. An acoustic shoe-box room simulator is used to generate a large number of binaural single-source audio scenes. These scenes are used to build a dataset of spatial binaural features annotated with acoustic properties such as the 3D source position and the walls' absorption coefficients. A probabilis-tic high-to low-dimensional regression framework is used to learn a mapp...

  5. 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...

  6. 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...

  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. Effects of posture on dynamic back loading during a cable lifting task

    Energy Technology Data Exchange (ETDEWEB)

    Gallagher, S.; Marras, W.S.; Davis, K.G.; Kovacs, K. [NIOSH, Pittsburgh, PA (United States). Pittsburgh Research Lab.

    2002-04-01

    Spinal loads associated with lifting and hanging heavy mining cable in a variety of postures were evaluated. This electrical cable can weigh up to 10 kg per metre and is often lifted in restricted spaces in underground coal mines. Seven male subjects performed eight cable lifting and hanging tasks, while trunk kinematic data and trunk muscle electromyograms (EMGs) were obtained. The eight tasks were combinations of four postures (standing, stooping, kneeling on one knee, or kneeling on both knees) and two levels of cable load (0 N or 100 N load added to the existing cable weight). An EMG-assisted model was used to calculate forces and moments acting on the lumbar spine. A two-way split-plot ANOVA showed that increased load (p<0.05) and changes in lifting posture (p<0.05) independently affected trunk muscle recruitment and spinal loading. The increase in cable load resulted in higher EMG activity of all trunk muscles and increased axial and lateral bending moments on the spine (p<0.05). Changes in posture caused more selective adjustments in muscle recruitment and affected the sagittal plane moment (p<0.05). Despite the more selective nature of trunk EMG changes due to posture, the magnitude of changes in spinal loading was often quite dramatic. However, average compression values exceeded 3400 N for all cable lifting tasks.

  10. Effects of automation and task load on task switching during human supervision of multiple semi-autonomous robots in a dynamic environment.

    Science.gov (United States)

    Squire, P N; Parasuraman, R

    2010-08-01

    The present study assessed the impact of task load and level of automation (LOA) on task switching in participants supervising a team of four or eight semi-autonomous robots in a simulated 'capture the flag' game. Participants were faster to perform the same task than when they chose to switch between different task actions. They also took longer to switch between different tasks when supervising the robots at a high compared to a low LOA. Task load, as manipulated by the number of robots to be supervised, did not influence switch costs. The results suggest that the design of future unmanned vehicle (UV) systems should take into account not simply how many UVs an operator can supervise, but also the impact of LOA and task operations on task switching during supervision of multiple UVs. The findings of this study are relevant for the ergonomics practice of UV systems. This research extends the cognitive theory of task switching to inform the design of UV systems and results show that switching between UVs is an important factor to consider.

  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. 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.

  13. 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.

  14. Dynamic effects of self-relevance and task on the neural processing of emotional words in context

    Directory of Open Access Journals (Sweden)

    Eric C. Fields

    2016-01-01

    Full Text Available 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 & 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 versus 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. Decision Integration and Support Engine (DISE) for dynamic aircraft and ISR asset tasking/retasking decision support for the AOC

    Science.gov (United States)

    VonPlinsky, Michael J.; Crowder, Ed

    2002-07-01

    The Decision Integration and Support Environment (DISE) is a Bayesian network (BN) based modeling and simulation of the target nomination and aircraft tasking decision processes. DISE operates in event driven interactions with FTI's AOC model, being triggered from within the Time Critical Target (TCT) Operations cell. As new target detections are received by the AOC from off-board ISR sources and processed by the Automatic Target Recognition (ATR) module in the AOC, DISE is called to determine if the target should be prosecuted, and if so, which of the available aircraft should be tasked to attack it. A range of decision criteria, with priorities established off-line and input into the tool, are associated with this process. DISE, when running in its constructive mode, automatically selects the best-suited aircraft and assigns the new target. In virtual mode, with a human operator, DISE presents the user with a suitability ranked list of the available aircraft for assignment. Recent DISE enhancements are applying this concept to the prioritization and scheduling of ISR support requests from Users to support both latent and dynamic tasking and scheduling of both space-based and airborne ISR assets.

  16. A model for dynamic allocation of human attention among multiple tasks

    Science.gov (United States)

    Sheridan, T. B.; Tulga, M. K.

    1978-01-01

    The problem of multi-task attention allocation with special reference to aircraft piloting is discussed with the experimental paradigm used to characterize this situation and the experimental results obtained in the first phase of the research. A qualitative description of an approach to mathematical modeling, and some results obtained with it are also presented to indicate what aspects of the model are most promising. Two appendices are given which (1) discuss the model in relation to graph theory and optimization and (2) specify the optimization algorithm of the model.

  17. EFFECTIVENESS OF DYNAMIC WRIST SPLINT ON DELTOID MUSCLE ACTIVITY USING FUNCTIONAL TASK PRACTICE IN POST STROKE PATIENTS

    Directory of Open Access Journals (Sweden)

    Jalaja Prakash

    2013-06-01

    Full Text Available Background:The study is to analyze the effectiveness of dynamic wrist splint on deltoid muscle activity usingfunctional task practice along with strengthening exercises in post stroke patients.Materials and Methods:Experimental study with sampling size 30 patients Group A: 15 patients. Group B: 15 patients. Sampling methodis convenient random sampling. Intervention period: 4 weeks. Settings: Bhagwan Mahaveer Jain Hospital, Vasanthnagar, Bangalore.The patient will be received; history will be taken; explained about the treatment session andinformed written consent will be taken. Patient will be made to sit comfortably. Check for safety i.e.; with armrest, back rest if necessary provide cushion. Dynamic wrist splint of appropriate size will be taken; checked forfitting of the splint for any compression and avoid other complications The initial muscle activityprior to treat-ment will be measured using EMG for deltoid. Group A: The patient will be asked to perform a given set ofactivities or tasks with splint. Group B: The patient will be asked to perform a given set of activities or taskswithout splint Each session would last for 30 minutes and frequency of 3-4 times per week. At the end oftreatment, surface EMG for deltoid is taken to check for the effectiveness of use of splint with work task duringthe rehabilitation program.Results:After 4weeks treatment period, the subjects in the group A were com-pared with the subjects in the group B. Group B had shown a significant difference with outcome measureswhen compared to group AConclusion:It is evident from the results that the subjects who used the thumbabduction supinator splint showed significant level of improvement in function and increase in deltoid muscleactivity when compared with subjects who did not use the splint as quantified using Fugl Meyer Scalefor UpperExtremity and Surface EMG.

  18. 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 media...... on the at-ear signals favored a sound-power summation model, according to which the maximum binaural gain is only 3dB, over competing models based on larger gains, or on the summation of monaural loudness indices....... planes. Matches were obtained via a two-interval, adaptive forced-choice (2AFC) procedure for three center frequencies (0.4, 1 and 5 kHz) and two overall levels (45 and 65 dB SPL). The results showed that loudness is not constant over sound incidence angles, with directional sensitivity varying over...... 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...

  19. 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.

  20. Prediction of the influence of reverberation on binaural speech intelligibility in noise and in quiet.

    Science.gov (United States)

    Rennies, Jan; Brand, Thomas; Kollmeier, Birger

    2011-11-01

    Reverberation usually degrades speech intelligibility for spatially separated speech and noise sources since spatial unmasking is reduced and late reflections decrease the fidelity of the received speech signal. The latter effect could not satisfactorily be predicted by a recently presented binaural speech intelligibility model [Beutelmann et al. (2010). J. Acoust. Soc. Am. 127, 2479-2497]. This study therefore evaluated three extensions of the model to improve its predictions: (1) an extension of the speech intelligibility index based on modulation transfer functions, (2) a correction factor based on the room acoustical quantity "definition," and (3) a separation of the speech signal into useful and detrimental parts. The predictions were compared to results of two experiments in which speech reception thresholds were measured in a reverberant room in quiet and in the presence of a noise source for listeners with normal hearing. All extensions yielded better predictions than the original model when the influence of reverberation was strong, while predictions were similar for conditions with less reverberation. Although model (3) differed substantially in the assumed interaction of binaural processing and early reflections, its predictions were very similar to model (2) that achieved the best fit to the data.

  1. 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.

  2. A binaural Web-based tour of the acoustics of Troy Music Hall

    Science.gov (United States)

    Torres, Rendell R.; Cooney, James; Shimizu, Yasushi

    2001-05-01

    For classical music to become more widely enjoyed, it must sound exciting. We hypothesize that if people could hear examples of truly exciting acoustics, classical music would be perceived less as a rarefied delicacy and more as a viscerally engaging listening experience. The Troy Savings Bank Music Hall in Troy, New York, is a legendary 1200-seat concert hall famous for its acoustics. Such landmarks are commonly documented architecturally but with few attempts to document their acoustics in a way that it is listenable. Thus, the goal is to capture and sonically disseminate the hall's acoustics through a Web-based acoustical tour, where one can click on various seats to hear binaural auralizations of different instruments and see corresponding views of the stage. The hope is that these auralizations will not only sonically document the acoustics of the hall but also tantalize even geographically distant listeners with binaural samples of how exciting music can be in excellent acoustics. The fun and challenges of devising (let alone standardizing) such an auralization-based system of documentation will be discussed, and a demonstration given. This process can be applied to other historically and acoustically significant spaces. [Work supported by the National Endowment for the Arts.

  3. A Binaural Neuromorphic Auditory Sensor for FPGA: A Spike Signal Processing Approach.

    Science.gov (United States)

    Jimenez-Fernandez, Angel; Cerezuela-Escudero, Elena; Miro-Amarante, Lourdes; Dominguez-Moralse, Manuel Jesus; de Asis Gomez-Rodriguez, Francisco; Linares-Barranco, Alejandro; Jimenez-Moreno, Gabriel

    2017-04-01

    This paper presents a new architecture, design flow, and field-programmable gate array (FPGA) implementation analysis of a neuromorphic binaural auditory sensor, designed completely in the spike domain. Unlike digital cochleae that decompose audio signals using classical digital signal processing techniques, the model presented in this paper processes information directly encoded as spikes using pulse frequency modulation and provides a set of frequency-decomposed audio information using an address-event representation interface. In this case, a systematic approach to design led to a generic process for building, tuning, and implementing audio frequency decomposers with different features, facilitating synthesis with custom features. This allows researchers to implement their own parameterized neuromorphic auditory systems in a low-cost FPGA in order to study the audio processing and learning activity that takes place in the brain. In this paper, we present a 64-channel binaural neuromorphic auditory system implemented in a Virtex-5 FPGA using a commercial development board. The system was excited with a diverse set of audio signals in order to analyze its response and characterize its features. The neuromorphic auditory system response times and frequencies are reported. The experimental results of the proposed system implementation with 64-channel stereo are: a frequency range between 9.6 Hz and 14.6 kHz (adjustable), a maximum output event rate of 2.19 Mevents/s, a power consumption of 29.7 mW, the slices requirements of 11141, and a system clock frequency of 27 MHz.

  4. 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

    -installed communication infrastructure. Owing to potential threats in the field environment and the unique features of MANET (e.g. the open nature of wireless links and the absence of security infrastructure), security of communications over MANET is a serious issue that is typically addressed by asymmetric cryptographic...... 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......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...

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  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

    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......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...

  11. Blade loss transient dynamics analysis, volume 1. Task 2: TETRA 2 theoretical development

    Science.gov (United States)

    Gallardo, Vincente C.; Black, Gerald

    1986-01-01

    The theoretical development of the forced steady state analysis of the structural dynamic response of a turbine engine having nonlinear connecting elements is discussed. Based on modal synthesis, and the principle of harmonic balance, the governing relations are the compatibility of displacements at the nonlinear connecting elements. There are four displacement compatibility equations at each nonlinear connection, which are solved by iteration for the principle harmonic of the excitation frequency. The resulting computer program, TETRA 2, combines the original TETRA transient analysis (with flexible bladed disk) with the steady state capability. A more versatile nonlinear rub or bearing element which contains a hardening (or softening) spring, with or without deadband, is also incorporated.

  12. 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.

  13. 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...

  14. Blade loss transient dynamics analysis, volume 2. Task 2: TETRA 2 user's manual

    Science.gov (United States)

    Black, Gerald; Gallardo, Vincente C.

    1986-01-01

    This is the user's manual for the TETRA 2 Computer Code, a program developed in the NASA-Lewis Blade Loss Program. TETRA 2 calculates a turbine engine's dynamic structural response from applied stimuli. The calculation options are: (1) transient response; and (2) steady state forced response. Based on the method of modal syntheses, the program allows the use of linear, as well as nonlinear connecting elements. Both transient and steady state options can include: flexible Bladed Disk Module, and Nonlinear Connecting Elements (including deadband, hardening/softening spring). The transient option has the additional capability to calculate response with a squeeze film bearing module. TETRA 2 output is summarized in a plotfile which permits post processing such as FFT or graphical animation with the proper software and computer equipment.

  15. Agent Dynamic Task Allocation Based on Improved Contract Net Protocol%改进合同网协议的Agent动态任务分配

    Institute of Scientific and Technical Information of China (English)

    杨萍; 刘颖; 裴莹

    2011-01-01

    针对导弹作战任务规划中的动态任务分配问题,研究了MAS框架下任务分配的形式化描述和数学模型,对动态任务分配的特点进行了分析,运用合同网理论,提出了基于改进合同网协议的Agent动态任务分配算法,实现了对不确定开放环境中动态变化的任务分配方法.算例表明算法是有效的.%Aimed to dynamic task allocation problem in missile planning system, the formalization description and mathematic model about task allocation are studied. The characteristic of dynamic task allocation is analyzed. An improved contract net algorithm about Agent dynamic task allocation problem is proposed. The algorithm settles the dynamic task allocation problem in uncertain opening environment. The example shows the algorithm is effective.

  16. 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.

  17. 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.

  18. Multiple Agent Dynamic Task Allocation Algorithm Research Based on Dynamic Fuzzy Sets%基于动态模糊集的多Agent动态任务分配算法研究

    Institute of Scientific and Technical Information of China (English)

    殷凡; 牛丽

    2013-01-01

    In order to improve the efficiency of multi-agent dynamic task allocation, we do task assignment study at the theory of dynamic fuzzy set. Firstly, we introduce the relative definition and mathematical model of dynamic fuzzy set, then we conduct example simulation, It provide relevant multi-agent dynamic task allocation algorithm and do example test. The experience result shows that this method can well solved the problems in the multi-agent dynamic task allocation. Besides, it improved the efficiency of dynamic task allocation in a great extent, which has a high research value.%为了提高多Agent动态任务分配的效率,借助于动态模糊集理论对任务分配进行研究。首先详细介绍了动态模糊集相关定义和数学模型,接着进行实例仿真,给出相关的多Agent动态任务分配算法并进行实例测试。实验结果表明,此方法很好地解决了多Agent系统中动态任务分配的问题,并且在很大程度上提高了动态任务分配的效率,具有一定的研究价值。

  19. 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

  20. NASA's Functional Task Test: Effects of Spaceflight and Six Degree Head-Down Bedrest on Dynamic Postural Stability

    Science.gov (United States)

    Taylor, L. C.; Batson, C. D.; Buxton, R. E.; Feiveson, A. H.; Kofman, I. S.; Laurie, S.; Lee, S. M. C.; Miller, C. A.; Mulavara, A. P.; Peters, B. T.; Phillips, T.; Platts, S. H.; Ploutz-Snyder, L. L.; Reschke, M. F.; Ryder, J. W.; Stenger, M. B.; Wood, S. J.; Bloomberg, J. J.

    2015-01-01

    The goals of the Functional Task Test (FTT) study were to determine the effects of spaceflight on functional tests that are representative of critical exploration mission tasks and to identify the physiological factors that contribute to decrements in performance.

  1. Temporal dynamics of interference in Simon and Eriksen tasks considered within the context of a dual-process model.

    Science.gov (United States)

    Mansfield, Karen L; van der Molen, Maurits W; Falkenstein, Michael; van Boxtel, Geert J M

    2013-08-01

    Behavioral and brain potential measures were employed to compare interference in Eriksen and Simon tasks. Assuming a dual-process model of interference elicited in speeded response tasks, we hypothesized that only lateralized stimuli in the Simon task induce fast S-R priming via direct unconditional processes, while Eriksen interference effects are induced later via indirect conditional processes. Delays to responses for incongruent trials were indeed larger in the Eriksen than in the Simon task. Only lateralized stimuli in the Simon task elicited early S-R priming, maximal at parietal areas. Incongruent flankers in the Eriksen task elicited interference later, visible as a lateralized N2. Eriksen interference also elicited an additional component (N350), which accounted for the larger behavioral interference effects in the Eriksen task. The findings suggest that interference and its resolution involve different processes for Simon and Eriksen tasks.

  2. 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

  3. 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

  4. 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 b...

  5. 基于动态规划算法的云任务分配策略%Cloud task allocation strategy based on dynamic programming algorithm

    Institute of Scientific and Technical Information of China (English)

    赵立慧; 李美安; 王蒙

    2013-01-01

    针对已有的基于蚁群算法的任务分配策略资源利用率低、算法时间复杂度高、任务分配效率低的问题,提出一种基于动态规划算法的任务分配策略.该算法利用动态规划的思想将等待执行任务均分后动态分配给不同节点,在迭代计算后得到任务分配最优方案,保证任务完成时间为全局最短完成时间,从而提高资源利用率,降低时间复杂度,减少时间的耗费.通过理论分析和Cloudsim仿真实验证明基于动态规划算法的云任务分配时间复杂度低,任务完成时间短,能够提高任务分配效率.%The existing task allocation strategy based on ant colony algorithm has many problems like low resource utilizaton rate,high algorithm time complexity and low efficiency of the allocation of tasks.The authors put forward a task allocation strategy based on dynamic programming algorithm.The algorithm applied dynamic programming ideas and divided the waiting task into average parts then distributed them to different nodes dynamically,the optimal plan for task allocation obtained after the iterative calculation,ensuring the task completion time be the shortest one,so as to improve resource utilization rate,and reduce the time complexity.The theoretical analysis and Cloudsim simulation results prove that the time complexity of the cloud task allocation based on dynamic programming algorithm is low and the task completion time is short.The results show that this method can improve the efficiency of the allocation of tasks.

  6. 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.

  7. Synthetic Aperture Computation as the Head is Turned in Binaural Direction Finding

    Directory of Open Access Journals (Sweden)

    Duncan Tamsett

    2017-03-01

    Full Text Available Binaural systems measure instantaneous time/level differences between acoustic signals received at the ears to determine angles λ between the auditory axis and directions to acoustic sources. An angle λ locates a source on a small circle of colatitude (a lamda circle on a sphere symmetric about the auditory axis. As the head is turned while listening to a sound, acoustic energy over successive instantaneous lamda circles is integrated in a virtual/subconscious field of audition. The directions in azimuth and elevation to maxima in integrated acoustic energy, or to points of intersection of lamda circles, are the directions to acoustic sources. This process in a robotic system, or in nature in a neural implementation equivalent to it, delivers its solutions to the aurally informed worldview. The process is analogous to migration applied to seismic profiler data, and to that in synthetic aperture radar/sonar systems. A slanting auditory axis, e.g., possessed by species of owl, leads to the auditory axis sweeping the surface of a cone as the head is turned about a single axis. Thus, the plane in which the auditory axis turns continuously changes, enabling robustly unambiguous directions to acoustic sources to be determined.

  8. 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.

  9. 基于拍卖的动态任务分配算法%Dynamic Task Allocation Algorithm Based on Auction

    Institute of Scientific and Technical Information of China (English)

    陶雪丽; 李双群

    2012-01-01

    Dynamic task allocation is a key issue of open multi-agent system(MAS). Based on the algorithm given by the reference [9] , this paper presents an improved algorithm for a new task appearing at any time in the process of task allocation or executing. The paper takes into account the Agent's expectation of the known tasks and future tasks, in order to guide the agent reasonable bid to get the optimum alloction. With multi-agent transporting army supplies for background, the results show that the algorithm is reasonable and effective.%动态任务分配是开放式MAS系统研究的重点.在文献[9]给出的算法基础上,针对任务分配或执行过程中,随时有新任务出现的情况,本文提出一种改进算法,同时考虑Agent对已知任务和未来任务的期望度,以引导Agent合理出价,从而得到较优的分配结果.通过在多Agent运输军需问题中的应用,验证了该算法是合理有效的.

  10. The binaural masking-level difference of mandarin tone detection and the binaural intelligibility-level difference of mandarin tone recognition in the presence of speech-spectrum noise.

    Science.gov (United States)

    Ho, Cheng-Yu; Li, Pei-Chun; Chiang, Yuan-Chuan; Young, Shuenn-Tsong; Chu, Woei-Chyn

    2015-01-01

    Binaural hearing involves using information relating to the differences between the signals that arrive at the two ears, and it can make it easier to detect and recognize signals in a noisy environment. This phenomenon of binaural hearing is quantified in laboratory studies as the binaural masking-level difference (BMLD). Mandarin is one of the most commonly used languages, but there are no publication values of BMLD or BILD based on Mandarin tones. Therefore, this study investigated the BMLD and BILD of Mandarin tones. The BMLDs of Mandarin tone detection were measured based on the detection threshold differences for the four tones of the voiced vowels /i/ (i.e., /i1/, /i2/, /i3/, and /i4/) and /u/ (i.e., /u1/, /u2/, /u3/, and /u4/) in the presence of speech-spectrum noise when presented interaurally in phase (S0N0) and interaurally in antiphase (SπN0). The BILDs of Mandarin tone recognition in speech-spectrum noise were determined as the differences in the target-to-masker ratio (TMR) required for 50% correct tone recognitions between the S0N0 and SπN0 conditions. The detection thresholds for the four tones of /i/ and /u/ differed significantly (pMandarin tones were all lower in the SπN0 condition than in the S0N0 condition, and the BMLDs ranged from 7.3 to 11.5 dB. The TMR for 50% correct Mandarin tone recognitions differed significantly (pMandarin tone detection and recognition in the presence of speech-spectrum noise are improved when phase inversion is applied to the target speech. The average BILDs of Mandarin tones are smaller than the average BMLDs of Mandarin tones.

  11. Quantifying Human Performance of a Dynamic Military Target Detection Task: An Application of the Theory of Signal Detection.

    Science.gov (United States)

    1995-06-01

    applied to analyze numerous experimental tasks (Macmillan and Creelman , 1991). One of these tasks, target detection, is the subject research. In...between each associated pair of false alarm rate and hit rate z-scores is d’ for the bias level associated with the pairing (Macmillan and Creelman , 1991...unequal variance in normal distributions (Macmillan and Creelman , 1991). 61 1966). It is described in detail for the interested reader by Green and

  12. 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

  13. Research on Multi-Agent Dynamic Task Allocation Algorithm and Based on Dynamic Fuzzy Set%基于DFS的多Agent动态任务分配算法研究

    Institute of Scientific and Technical Information of China (English)

    张瑜; 李凡长

    2009-01-01

    Task allocation problem is one of the import researches of multi-agent system. For the complex problem, many researchers from different points of view put forward a variety of effective algorithms. These algorithms are effective for the determinative environment,but for the uncertain and dynamic environment are deficient. In mis paper,fuzzy characteristics of dynamic task environment are researched,using dynamic fuzzy set theory,given the relevant multi-Agent dynamic task allocation algorithm.Examples of the test show that the algorithm model can be a reasonable simulation of MAS system operation task allocation process, and have achieved the optimal task allocation strategy and a good effect.%任务分配问题是MAS的重要研究内容之一,对于任务分配这一复杂问题,很多研究者从不同的角度提出各种行之有效的算法.这些算法对于确定的环境是有效的,对于不确定的动态的环境存在不足.本文针对具有动态模糊特性的任务环境进行研究,借助动态模糊集理论,给出了相关的多Agent动态任务分配算法.实例测试表明,算法模型可以合理地模拟MAS系统中任务分配的运行过程,并获得最优的任务分配策略和良好的任务实现效果.

  14. 面向业务的动态任务分配工作模型定义%Definition for business-oriented dynamic task allocation work model

    Institute of Scientific and Technical Information of China (English)

    李春芳; 徐建军

    2014-01-01

    To solve the deficiency of the complete business-oriented dynamic task allocation work model and the unclarity of working relationships among the model’s constitutions ,a strategy-first dynamic task allocation work model S-DTAWM was pro-posed .Using the mathematical set theory , the components , relationships and executing algorithms of the work model S-DTAWM were formalized ,and a foundation for the research and the practice of the universal task allocation system was built . Then cases used in the approving and examining process for the bank credit were provided to illustrate the use of the work model .%为解决面向业务的完整动态任务分配工作模型缺失以及组成内容之间工作关系语义不清晰的问题,提出策略优先的动态任务分配工作模型S-DTAWM。利用集合论的描述语言,形式化定义S-DTAWM 各构件内容、工作关系及执行算法,为面向业务的通用动态任务分配系统构建奠定基础。通过相应模型在银行信贷审批过程的具体案例表明其应用方法。

  15. 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.

  16. Enabling Dynamic Process Simulators to Perform Alternative Tasks: A Time-stepper Based Toolkit for Computer-Aided Analysis

    OpenAIRE

    Siettos, C. I.; Pantelides, C. C.; Kevrekidis, I.G.

    2003-01-01

    We discuss computational superstructures that, using repeated, appropriately initialized short calls, enable temporal process simulators to perform alternative tasks such as fixed point computation, stability analysis and projective integration. We illustrate these concepts through the acceleration of a gPROMS-based Rapid Pressure Swing Adsorption simulation, and discuss their scope and possible extensions.

  17. Interaction against different environmental dynamics during a leg extension task is controlled by temporal rather than amplitude scaling of muscular activity.

    Science.gov (United States)

    Wuebbenhorst, Kati; Zschorlich, Volker

    2013-10-01

    Force exertion against different mechanical environments can affect motor control strategies in order to account for the altered environmental dynamics and to maintain the ability to produce force. Here, we investigated the change of muscular activity of selected muscles of the lower extremities while the participants interacted with an external mechanical device of variable stability. Twenty-five healthy participants exerted force against the device by performing a unilateral ballistic leg extension task under 1 or 3 degrees of freedom (DoF). Directional force data and electromyographic responses from four leg muscles (TA, VM, GM, PL) were recorded. Muscle responses to the altered experimental conditions were analyzed by calculating time to peak electrical activity (TTP), peak electrical activity (PEA), slope of EMG-signal and muscle activity. It was found that neuromuscular system adjustments to the task are expressed mainly by temporal (TTP) rather than amplitude (PEA) scaling of muscular activity. This change was specific for the investigated muscles. Moreover, a selective increase of muscle activity occurred while increasing external DoF. This scheme was accompanied by a significant reduction of applicable force against the device in the unstable 3 DoF condition. The findings suggest that orchestration of movement control is linked to environmental dynamics also affecting the ability to produce force under dynamic conditions. The adjustments of the neuromuscular system are rather temporal in nature being consistent with the impulse timing hypothesis of motor control.

  18. 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.

  19. 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.

  20. Subject-Specific Tendon-Aponeurosis Definition in Hill-Type Model Predicts Higher Muscle Forces in Dynamic Tasks

    OpenAIRE

    Pauline Gerus; Guillaume Rao; Eric Berton

    2012-01-01

    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 subjec...

  1. 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.

  2. 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.

  3. Visuo-postural adaptation during the acquisition of a visually guided weight-shifting task: age-related differences in global and local dynamics.

    Science.gov (United States)

    Hatzitaki, Vassilia; Konstadakos, Stylianos

    2007-10-01

    The effects of aging on the acquisition of a novel visuo-postural coordination task were addressed at two levels: (a) changes in the intersegmental coordination (local dynamics) (b) changes in the coupling of postural sway to the visual driving stimulus (global dynamics). Twelve elderly (age: 71.2 +/- 6.4 years; height: 169.3 +/- 3.8 cm; mass: 72.4 +/- 6.1 kg) and 12 young women (age: 27.1 +/- 4.9 years; height: 178.3 +/- 2.9 cm; mass: 56.7 +/- 4.1 kg) practiced a visually guided Weight-Shifting (WS) task while standing on a dual force platform. The participants were asked to keep the vertical force applied by each limb within a +/-30% force boundary that was visually specified by a target sine-wave signal. Practice consisted of three blocks of five trials performed in 1-day, followed by a block of five trials performed 24 h later. Ground reaction forces and segment (shank, pelvis, and upper trunk) angular kinematics were synchronously sampled through an A/D acquisition board and further analyzed employing spectral and coherence analysis. Elderly women had longer WS cycles, lower response gain, and higher within-trial variability, suggesting a weaker coupling between the visual stimulus and the response force. Spectral analysis of the ground reaction forces confirmed that regardless of age, visuo-postural coupling improved with practice. However, the recruitment of local degrees of freedom was different between the two age groups. With practice, young performers increased peak coherence between the pelvis and the upper trunk and reduced peak power of segment oscillations in the pitch direction. On the other hand, elderly women decreased active upper trunk rotation while shifting control to the lower limb. It is suggested that different functional coordination solutions are possible for attaining the same overall task goal. These solutions are determined by age-related constraints in the physiological systems supporting postural control.

  4. 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.

  5. Your eyes give you away: prestimulus changes in pupil diameter correlate with poststimulus task-related EEG dynamics.

    Science.gov (United States)

    Hong, Linbi; Walz, Jennifer M; Sajda, Paul

    2014-01-01

    Pupillary measures have been linked to arousal and attention as well as activity in the brainstem's locus coeruleus norepinephrine (LC-NE) system. Similarly, there is evidence that evoked EEG responses, such as the P3, might have LC-NE activity as their basis. Since it is not feasible to record electrophysiological data directly from the LC in humans due to its location in the brainstem, an open question has been whether pupillary measures and EEG variability can be linked in a meaningful way to shed light on the nature of the LC-NE role in attention and arousal. We used an auditory oddball task with a data-driven approach to learn task-relevant projections of the EEG, for windows of data spanning the entire trial. We investigated linear and quadratic relationships between the evoked EEG along these projections and both prestimulus (baseline) and poststimulus (evoked dilation) pupil diameter measurements. We found that baseline pupil diameter correlates with early (175-200 ms) and late (350-400 ms) EEG component variability, suggesting a linear relationship between baseline (tonic) LC-NE activity and evoked EEG. We found no relationships between evoked EEG and evoked pupil dilation, which is often associated with evoked (phasic) LC activity. After regressing out reaction time (RT), the correlation between EEG variability and baseline pupil diameter remained, suggesting that such correlation is not explainable by RT variability. We also investigated the relationship between these pupil measures and prestimulus EEG alpha activity, which has been reported as a marker of attentional state, and found a negative linear relationship with evoked pupil dilation. In summary, our results demonstrate significant relationships between prestimulus and poststimulus neural and pupillary measures, and they provide further evidence for tight coupling between attentional state and evoked neural activity and for the role of cortical and subcortical networks underlying the process of

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

    Science.gov (United States)

    Gerus, Pauline; Rao, Guillaume; Berton, Eric

    2012-01-01

    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 in agreement with

  7. 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

  8. Visually guided auditory attention in a dynamic "cocktail-party" speech perception task: ERP evidence for age-related differences.

    Science.gov (United States)

    Getzmann, Stephan; Wascher, Edmund

    2017-02-01

    Speech understanding in the presence of concurring sound is a major challenge especially for older persons. In particular, conversational turn-takings usually result in switch costs, as indicated by declined speech perception after changes in the relevant target talker. Here, we investigated whether visual cues indicating the future position of a target talker may reduce the costs of switching in younger and older adults. We employed a speech perception task, in which sequences of short words were simultaneously presented by three talkers, and analysed behavioural measures and event-related potentials (ERPs). Informative cues resulted in increased performance after a spatial change in target talker compared to uninformative cues, not indicating the future target position. Especially the older participants benefited from knowing the future target position in advance, indicated by reduced response times after informative cues. The ERP analysis revealed an overall reduced N2, and a reduced P3b to changes in the target talker location in older participants, suggesting reduced inhibitory control and context updating. On the other hand, a pronounced frontal late positive complex (f-LPC) to the informative cues indicated increased allocation of attentional resources to changes in target talker in the older group, in line with the decline-compensation hypothesis. Thus, knowing where to listen has the potential to compensate for age-related decline in attentional switching in a highly variable cocktail-party environment.

  9. 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...

  10. Comparison of Proximally Versus Distally Placed Spatially Distributed Sequential Stimulation Electrodes in a Dynamic Knee Extension Task.

    Science.gov (United States)

    Laubacher, Marco; Aksöz, Efe A; Binder-Macleod, Stuart; Hunt, Kenneth J

    2016-06-13

    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.

  11. Comparison of Proximally Versus Distally Placed Spatially Distributed Sequential Stimulation Electrodes in a Dynamic Knee Extension Task

    Science.gov (United States)

    Laubacher, Marco; Aksöz, Efe A.; Binder-Macleod, Stuart; Hunt, Kenneth J.

    2016-01-01

    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. PMID:27478563

  12. 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.

  13. 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.

  14. Long-Term Task- and Dopamine-Dependent Dynamics of Subthalamic Local Field Potentials in Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Sara J. Hanrahan

    2016-11-01

    Full Text Available Subthalamic nucleus (STN local field potentials (LFP are neural signals that have been shown to reveal motor and language behavior, as well as pathological parkinsonian states. We use a research-grade implantable neurostimulator (INS with data collection capabilities to record STN-LFP outside the operating room to determine the reliability of the signals over time and assess their dynamics with respect to behavior and dopaminergic medication. Seven subjects were implanted with the recording augmented deep brain stimulation (DBS system, and bilateral STN-LFP recordings were collected in the clinic over twelve months. Subjects were cued to perform voluntary motor and language behaviors in on and off medication states. The STN-LFP recorded with the INS demonstrated behavior-modulated desynchronization of beta frequency (13–30 Hz and synchronization of low gamma frequency (35–70 Hz oscillations. Dopaminergic medication did not diminish the relative beta frequency oscillatory desynchronization with movement. However, movement-related gamma frequency oscillatory synchronization was only observed in the medication on state. We observed significant inter-subject variability, but observed consistent STN-LFP activity across recording systems and over a one-year period for each subject. These findings demonstrate that an INS system can provide robust STN-LFP recordings in ambulatory patients, allowing for these signals to be recorded in settings that better represent natural environments in which patients are in a variety of medication states.

  15. 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

  16. A New DCCEM Dynamic Cloud Task Allocation Algorithm Research%一种新的 DCCEM 动态云任务分配算法研究

    Institute of Scientific and Technical Information of China (English)

    刘军华; 蔡卫红; 雷超阳

    2013-01-01

    This paper proposes a dynamic cloud task allocation algorithm model which can equally allocate the cloud tasks into the cloud group servers and gives full consideration to the different cloud servers for different business abilities .The algorithm solves the load balance of the cloud servers and uses the CPU resources efficiently so that the user can obtain higher service efficiency and the effective management of the cloud cluster environment calculation and storage resources can be achieved .By simulation comparison analysis ,the technique is proved to be effective ,which can not only make full use of the system resources ,but also realize the automatic regulation and load balancing of the resources .%提出了一种动态的云任务分配算法架构模型,其算法能将云任务平均分配到云群服务器中,充分考虑了不同云服务器针对不同业务能力,解决了云服务器的负载平衡,且能高效率地使用CPU资源,让使用者得到较高的服务效率,并让云群环境的计算及存储资源得到了有效管理。通过仿真比较分析,该技术是有效的,既能充分利用系统资源,又能实现资源的自动调节和负载均衡。

  17. A new asymmetric directional microphone algorithm with automatic mode-switching ability for binaural hearing support devices.

    Science.gov (United States)

    Kim, Jinryoul; Nam, Kyoung Won; Yook, Sunhyun; Jang, Dong Pyo; Kim, In Young; Hong, Sung Hwa

    2015-06-01

    For hearing support devices, it is important to minimize the negative effect of ambient noises for speech recognition but also, at the same time, supply natural ambient sounds to the hearing-impaired person. However, conventional fixed bilateral asymmetric directional microphone (DM) algorithms cannot perform in such a way when the DM-mode device and a dominant noise (DN) source are placed on the same lateral hemisphere. In this study, a new binaural asymmetric DM algorithm that can overcome the defects of conventional algorithms is proposed. The proposed algorithm can estimate the position of a specific DN in the 90°-270° range and switch directional- and omnidirectional-mode devices automatically if the DM-mode device and the DN are placed in opposite lateral hemispheres. Computer simulation and KEMAR mannequin recording tests demonstrated that the performance of the conventional algorithm deteriorated when the DM-mode device and the DN were placed in the opposite hemisphere; in contrast, the performance of the proposed algorithm was consistently maintained regardless of directional variations in the DN. Based on these experimental results, the proposed algorithm may be able to improve speech quality and intelligibility for hearing-impaired persons who have similar degrees of hearing impairment in both ears.

  18. Database of Multichannel In-Ear and Behind-the-Ear Head-Related and Binaural Room Impulse Responses

    Directory of Open Access Journals (Sweden)

    H. Kayser

    2009-01-01

    Full Text Available An eight-channel database of head-related impulse responses (HRIRs and binaural room impulse responses (BRIRs is introduced. The impulse responses (IRs were measured with three-channel behind-the-ear (BTEs hearing aids and an in-ear microphone at both ears of a human head and torso simulator. The database aims at providing a tool for the evaluation of multichannel hearing aid algorithms in hearing aid research. In addition to the HRIRs derived from measurements in an anechoic chamber, sets of BRIRs for multiple, realistic head and sound-source positions in four natural environments reflecting daily-life communication situations with different reverberation times are provided. For comparison, analytically derived IRs for a rigid acoustic sphere were computed at the multichannel microphone positions of the BTEs and differences to real HRIRs were examined. The scenes' natural acoustic background was also recorded in each of the real-world environments for all eight channels. Overall, the present database allows for a realistic construction of simulated sound fields for hearing instrument research and, consequently, for a realistic evaluation of hearing instrument algorithms.

  19. Human-System task integration

    NARCIS (Netherlands)

    Schraagen, J.M.C.

    2005-01-01

    The Dutch Ministry of Defence research programme Human-System Task Integration aims at acquiring knowledge for the optimal cooperation between human and computer, under the following constraints: freedom of choice in decisions to automate and multiple, dynamic task distributions. This paper describe

  20. 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.

  1. Task allocation in a distributed computing system

    Science.gov (United States)

    Seward, Walter D.

    1987-01-01

    A conceptual framework is examined for task allocation in distributed systems. Application and computing system parameters critical to task allocation decision processes are discussed. Task allocation techniques are addressed which focus on achieving a balance in the load distribution among the system's processors. Equalization of computing load among the processing elements is the goal. Examples of system performance are presented for specific applications. Both static and dynamic allocation of tasks are considered and system performance is evaluated using different task allocation methodologies.

  2. Metaphoric Displays for Dynamic Tasks

    Science.gov (United States)

    1987-03-01

    Interaction. Peirce , C. (1960). Collected paeers of Charles Sanders Peirce , Vol. i, Elements of loaic. Cambridge, MA: Harvard University Press. Spiro...representations is an ongoing processl. C. S. Peirce (1960) has provided a systematic theory of signs which 1We must also be careful to d~istinguish

  3. Dynamic Constellation Tasking and Management

    Science.gov (United States)

    2013-03-01

    performance of the orbit. Jared Krueger, Daniel Selva , Matthew Smith, and John Keesee searched for a method to determine the optimal spacecraft and...Krueger, Jared K., Daniel Selva , Matthew W. Smith, John Keesee. “Spacecraft and Constellation Design for a Continuous Responsive Imaging System in Space

  4. 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.

  5. Heuristic Algorithm for Dynamic Task Planning of Early Warning System of Low Earth Orbit%低轨预警系统动态任务规划启发式算法

    Institute of Scientific and Technical Information of China (English)

    简平; 邹鹏; 熊伟

    2013-01-01

    该文针对低轨预警系统任务动态规划需求,从预警传感器资源和导弹跟踪任务角度对低轨预警系统动态任务规划问题进行了形式化描述,建立了系统动态任务规划的动态约束满足问题模型。该模型包括两级优化目标跟踪精度、资源利用率、传感器切换率、松弛度综合优化指标和方案调整幅度(调整率)指标;提出了求解动态规划问题的变邻域启发式搜索算法,设计了算法的直接插入、重新分配、替换和删除邻域结构及算子。通过仿真实验验证了基于梯度优化目标的动态规划模型的合理性,并说明启发式算法能有效求解低轨预警系统动态任务规划问题。%The dynamic task planning issue of early warning system of Low Earth Orbit (LEO) is described by the system resource and missile tracking task aspects, and the Dynamic Constraint Satisfaction Problem (DCSP) model of system dynamic task planning is built which includes two level index the integrative optimizing indexes of tracking precision, task accomplishment, sensor switching and resource slack, the adjusting range of original task planning scheme. To solve the dynamic planning model, a variable neighborhood heuristic algorithm on the basis of original planning and schedule is put forward, and the directly insert, redistribute, replace and delete neighborhood structure and their operators are designed in the heuristic algorithm. The simulation results show the leveled dynamic planning model is rational and the heuristic algorithm can solve the dynamic task planning issue of early warning system of LEO effectively.

  6. Developmental Dynamics between Children's Externalizing Problems, Task-Avoidant Behavior, and Academic Performance in Early School Years: A 4-Year Follow-Up

    Science.gov (United States)

    Metsäpelto, Riitta-Leena; Pakarinen, Eija; Kiuru, Noona; Poikkeus, Anna-Maija; Lerkkanen, Marja-Kristiina; Nurmi, Jari-Erik

    2015-01-01

    This longitudinal study investigated the associations among children's externalizing problems, task-avoidant behavior, and academic performance in early school years. The participants were 586 children (43% girls, 57% boys). Data pertaining to externalizing problems (teacher ratings) and task-avoidant behaviors (mother and teacher ratings) were…

  7. EEG Feature Under Binaural Beat Stimulation%双耳差频声刺激下的脑电特征

    Institute of Scientific and Technical Information of China (English)

    周鹏; 高翔; 王晓璐; 綦宏志; 王学民; 明东

    2015-01-01

    为了研究双耳差频声刺激影响大脑状态的神经机制,采用功率谱、Lempel-Ziv复杂度(LZC)和基于互信息的脑网络等线性及非线性方法,深入探讨了两种不同模式的双耳差频声刺激(alpha & beta)对脑电的影响规律.13名受试者分别进行了alpha & beta差频刺激,结果表明自发脑电的功率谱并没有发现频率跟随响应效应,LZC也没有显著变化.而脑网络图则能够发现在 alpha 差频刺激下大脑皮层不同区域的信息连接性显著减弱,在 beta 差频声刺激下信息连接性则显著增强.因此,互信息脑网络图可以有效地监测大脑在双耳差频声刺激下的变化,为双耳差频声刺激的生物学效应提供了一种合理的解释.%In order to study the neural mechanism of brain state induced by binaural beat(BB),linear and nonlinear methods,such as power spectral density,Lempel-Ziv complexity(LZC)and brain network based on cross mutual information were applied to discuss the change of brain under two kinds of BB stimulations(alpha & beta). Thirteen subjects were involved in alpha & beta BB stimulations,and the results showed no frequency following re-sponse(FFR)by PSD of spontaneous electroencephalogram(EEG)and no obvious change by LZC. However,the information transmission among various cortical areas reduced under alpha BB stimulation but enhanced under beta BB stimulation by brain network. Therefore,brain network based on mutual information can effectively monitor the change of cerebral cortex under BB stimulation,which provides a new perspective for biological effects induced by BB stimulation.

  8. 对地观测卫星任务规划的启发式动态调整算法%Heuristic dynamic adjust of task scheduling for earth observing satellite

    Institute of Scientific and Technical Information of China (English)

    张利宁; 黄小军; 邱涤珊; 李皓平

    2011-01-01

    针对对地观测卫星任务规划,分析了单个资源失效与多个高优先级任务动态插入情况下已有任务规划方案的动态调整问题.以最大化规划方案任务权值总和为优化目标,提出了基于任务替换的启发式动态调整算法,包括选择替换任务的五种启发式策略:最大灵活度,最小冲突集,最小争议部分、区间剪枝以及任务剪枝策略.分析了影响动态调整算法运行效率的两个关键因素:冲突任务集与动态搜索深度.采用任务重规划率、规划权值变化率与算法运行时间三项指标考察算法效果,通过仿真实验验证了算法的可行性和有效性.%The dynamic adjust problem of task scheduling for multi-earth observing satellite is analyzed,in cases of single resource fail and multi-prior tasks' dynamic insertion.The optimizing objective is to maximize the sum of all scheduled tasks. The heuristic dynamic adjust algorithm has been proposed based on task swapping, including five heuristic strategies to choosing swapped task:maximum flexibility,minimum conflict set,minimum contention,interval prune and task prune.Two critical elements that impact efficiency of the algorithm have been analyzed also.Three indices, including re-scheduling ratio, change ratio of sum weight and total running time are deployed to check the result of this algorithm;the feasibility and effectiveness have been tested through simulation,and promised result is fulfilled.

  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. Influencia de la estimulación sonora binaural en la generación de ondas cerebrales. Estudio electroencefalográfico

    OpenAIRE

    2013-01-01

    Introducción y objetivos. La audición binaural permite al sistema auditivo realizar un correcto análisis de la información que portan las ondas sonoras al posibilitar la comparación de la señal que llega a cada oído. La relación de ambos lados de la vía auditiva sucede casi desde el inicio de la misma, ya en el tronco cerebral, mediante decusaciones de fibras al lado contralateral de la vía auditiva. De esta manera, la estimulación sonora influye en la actividad del sistema nervioso y, pos...

  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. 电力系统可靠性评估的动态任务分配并行算法%Parallel Algorithm for Reliability Evaluation of Bulk Power System with Dynamic Task Allocation Technique

    Institute of Scientific and Technical Information of China (English)

    胡博; 谢开贵; 赵渊; 曹侃

    2011-01-01

    针对大电力系统可靠性评估并行计算中静态任务分配方法存在的进程间通信次数多、过度计算等不足,在详细分析Monte-Carlo仿真过程中可靠性指标方差系数和抽样次数变化规律的基础上,提出基于De Miovre-Laplace中心极限定理和曲线拟合相结合的启发式动态任务分配方法,并提出基于动态任务分配的大规模电力系统可靠性评估并行算法.在并行任务分配过程中,根据已有的仿真信息对总抽样次数进行合理估计,使得单次任务分配量尽可能多,以达到减少进程间通信次数的目的.算例分析表明所述的动态任务分配方法可较好地提高并行效率.%To overcome the excessive communication and calculation problems in the bulk power system reliability evaluation with the static task allocation technique, the rules of reliability index square coefficients varying with the sampling times in Monte-Carlo method are analyzed. Based on the analyzing results, a parallel computation model for reliability evaluation of bulk power system is proposed using a dynamic task allocation technique, which is designed using the De Moivre-Laplace central limit theorem and the curve fitting method. Using the simulating information in the parallel task allocation process, a conservative evaluation technique for total sampling times can be used to maximize allocated processes in a single task and minimize the total communication times. Case studies show that the proposed dynamic task allocation method can improve the efficiency of parallel computation.

  13. 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

  14. 基于任务空间的无标定视觉机械臂自适应跟踪控制%Adaptive task-space tracking control for uncalibrated eye-to-hand systems with dynamic uncertainties

    Institute of Scientific and Technical Information of China (English)

    薛广月; 任雪梅

    2013-01-01

      In this paper, an adaptive task-space tracking control approach is designed by using the error caused by manipulator’s dynamic uncertainties and unknown camera calibration parameters. Due to the different uncertainties, the input signal of controller is designed in two steps. Firstly, an adaptive task-space tracking controller is designed to compensate the robotic dynamic uncertainty. Then, an adaptive camera calibration controller is established to ensure bounded image-space tracking error. Finally, an uniform controller is combined by using the errors in both image-space and task-space. Results of experiments show the effectiveness of the proposed method.%  针对动力学参数不确定的无标定视觉机械臂系统,研究基于任务空间的自适应控制问题。对于控制器的设计,首先研究机械臂动力学参数不确定情况下基于任务空间的控制问题,然后设计自适应摄像机标定控制器,最后根据任务空间信息和图像空间信息的一致收敛关系统一两部分控制器,设计整个闭环系统控制信号和自适应控制律。实验结果表明了所提出的控制方法的有效性。

  15. Multi-UAV Dynamic Task Assignment by Particle Swarm Optimization Algorithm Based on Division and Union Strategy%基于分合粒子群算法的多无人机任务重分配

    Institute of Scientific and Technical Information of China (English)

    许书诚; 王琪; 刘贤敏

    2012-01-01

    With the mission implemented by multi-UAV, the change of the battle field and formation state of UAV may cause failure of the original distribution plan or reduce efficiency, so it is necessary to execute multi-UAV dynamic task assignment again- Firstly, a formulation was proposed for it. Then task reassignment based on grouping was used. ,task grouping was implemented according to improved k-means algorithm, and particle swarm optimization algorithm based on division and union strategy was used to make task reassignment inside a group. In the end,a simulation proceeds.The simulation results indicate that the approach satisfies the requirements of the battle field.%多UAV在执行任务过程中,战场环境以及UAV编队状态的改变将导致原有的分配计划失效或效率降低,因此有必要重新分配任务.针对多无人机任务重分配问题,首先建立了相应的数学模型.其次运用分组基础上的任务重分配策略进行任务分配,提出了改进的K均值聚类算法进行初步分组,再在分组的基础下,提出了分合粒子群优化算法进行组内任务分配.最后进行实验仿真,实验结果与分析表明基于分合粒子群算法的任务重分配方法能有效地满足多变的战场环境要求.

  16. 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.

  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. Use of binaural cues for sound localization in two species of Phyllostomidae: the Greater spear-nosed bat (Phyllostomus hastatus) and the Short-tailed fruit bat (Carollia perspicillata).

    Science.gov (United States)

    Heffner, Rickye S; Koay, Gimseong; Heffner, Henry E

    2010-11-01

    Unlike humans, not all mammals use both of the binaural cues for sound localization. Whether an animal uses these cues can be determined by testing its ability to localize pure tones; specifically, low frequencies are localized using time-difference cues, and high frequencies are localized using intensity-difference cues. We determined the ability to use binaural cues in 2 New World bats, Phyllostomus hastatus, large omnivores, and Carollia perspicillata, small frugivores, by testing their tone-localization ability using a conditioned avoidance procedure. Both species easily localized high-frequency tones, indicating that they could use the interaural intensity-difference cue. However, neither species was able to use the phase-difference cue to localize either low-frequency pure tones or amplitude-modulated tones (which provided an envelope for additional time analysis). We now know of 3 bat species that cannot use binaural time cues and 2 that can. Further exploration of localization in bats may provide insight into the neural analysis of time cues in species that do not hear low frequencies.

  19. 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。

  20. 一种机场噪声等值线三维动态绘制的任务分配方法%A Task Allocation Method for Dynamic Three-dimensional Drawing of Airport Noise Isoline

    Institute of Scientific and Technical Information of China (English)

    徐涛; 呼和木其日

    2016-01-01

    Task allocation is one of the key factors to influence performance of cluster system ,which affects load balan-cing and resources utilization of cluster system .In dynamic three-dimensional drawing of airport noise isoline ,the drawing ac-curacy and noise computational complexity depends on grid spacing size .In this process ,how to allocate the noise computing tasks for the dynamic three-dimensional drawing of airport noise isoline to different server nodes in the cluster system and dy-namically control the grid spacing size is the important steps to increase the resources utilization of cluster system ,shorten the average response time and improve the accuracy of drawing noise isoline .In order to achieve these purposes ,this paper analyzes the environmental factors of area around the airport and distribution character of airport noise ,establishes relation-ship between the noise computation and the load of server node ,and then a task allocation model for dynamic three-dimen-sional drawing of airport noise isoline is proposed .The model is solved by genetic algorithm .The simulation results show that the proposed method allocates tasks balanced and makes full use of system resources ,shorten response time ,and finally a-chieve the real-time computing requirements for dynamic three-dimensional drawing of airport noise isoline .%任务分配方法是影响集群系统性能的关键所在,影响着集群系统的负载均衡和系统资源利用率。在机场噪声等值线三维动态绘制过程中,网格间距大小决定绘制精度和噪声计算量,如何将机场周围区域中的噪声计算任务分配到集群中不同服务器节点并动态控制网格间距是提高集群系统资源利用率、缩短平均响应时间和提高噪声等值线绘制精度的重要环节。针对上述目标,分析了机场周围环境结构因素和机场噪声分布特性,建立了噪声计算量与服务器负载之间的关系,从而构建面向机场

  1. "Task" as Research Construct

    Science.gov (United States)

    Seedhouse, Paul

    2005-01-01

    The article examines "task" as research construct as predominantly conceived in terms of task-as-workplan in the task-based learning/second language acquisition literature. It is suggested that "task" has weak construct validity and ontology in an overwhelmingly quantitative paradigm because the construct has a "split personality."…

  2. As good as the real thing? Performance differences for live versus recorded stimuli in an everyday listening task

    DEFF Research Database (Denmark)

    Kirkwood, Brent Christopher

    2005-01-01

    subjects listened to recordings presented via headphones and to the live presentation of wooden dowels of various lengths being dropped on a linoleum floor behind the screen. The subjects were asked to produce estimates of the rod lengths by positioning a moveable surface in such a way that it corresponded......In an attempt to understand the influence of stimulus presentation method for a typical everyday listening task, test subject performance in a dropped-rod length-estimate experiment was compared for three cases: 1) live presentation of stimuli, 2) playback of binaural stimuli as recorded from...... an acoustic head and torso simulator, and 3) diotic presentation of monaurally recorded stimuli. Live presentation of stimuli has already been used by C. Carello, et al. [Psychological Science 9, 211-214 (1998)] to demonstrate that humans can hear reasonably well the length of wooden dowels dropped onto hard...

  3. As good as the real thing? Performance differences for live versus recorded stimuli in an everyday listening task

    DEFF Research Database (Denmark)

    Kirkwood, Brent Christopher

    subjects listened to recordings presented via headphones and to the live presentation of wooden dowels of various lengths being dropped on a linoleum floor behind the screen. The subjects were asked to produce estimates of the rod lengths by positioning a moveable surface in such a way that it corresponded......In an attempt to understand the influence of stimulus presentation method for a typical everyday listening task, test subject performance in a dropped-rod length-estimate experiment was compared for three cases: 1) live presentation of stimuli, 2) playback of binaural stimuli as recorded from...... an acoustic head and torso simulator, and 3) diotic presentation of monaurally recorded stimuli. Live presentation of stimuli has already been used by C. Carello, et al. [Psychological Science 9, 211-214 (1998)] to demonstrate that humans can hear reasonably well the length of wooden dowels dropped onto hard...

  4. 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.

  5. 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.

  6. Sequential modulation of cue use in the task switching paradigm

    Directory of Open Access Journals (Sweden)

    Mike eWendt

    2012-08-01

    Full Text Available In task switching studies, pre-cuing of the upcoming task improves performance, indicating preparatory activation of the upcoming task set and/or inhibition of the previous task set. To further investigate cue-based task preparation, the authors presented both valid and invalid task cues in a task switching experiment involving three tasks. Consistent with previous findings, a validity effect in terms of higher reaction times on invalidly compared to validly cued tasks was obtained. However, this validity effect was reduced following invalidly cued trials, suggesting dynamic adjustment in terms of decreased cue-based preparation after being misled. Performance was particularly impaired when the current task was the one that was invalidly cued on the preceding trial. This finding may reflect either particular reluctance to prepare or persisting inhibition of the erroneously prepared task set from the pre-trial.

  7. Sequential Modulation of Cue Use in the Task Switching Paradigm

    Science.gov (United States)

    Wendt, Mike; Luna-Rodriguez, Aquiles; Reisenauer, Renate; Jacobsen, Thomas; Dreisbach, Gesine

    2012-01-01

    In task switching studies, pre-cuing of the upcoming task improves performance, indicating preparatory activation of the upcoming task-set, and/or inhibition of the previous task-set. To further investigate cue-based task preparation, the authors presented both valid and invalid task cues in a task switching experiment involving three tasks. Consistent with previous findings, a validity effect in terms of higher reaction times on invalidly compared to validly cued tasks was obtained. However, this validity effect was reduced following invalidly cued trials, suggesting dynamic adjustment in terms of decreased cue-based preparation after being misled. Performance was particularly impaired when the current task was the one that was invalidly cued on the preceding trial. This finding may reflect either particular reluctance to prepare or persisting inhibition of the erroneously prepared task-set from the pre-trial. PMID:22908004

  8. μC/OS-Ⅱ基于动态优先级的时间片轮转任务调度策略%Time slice rotation task scheduling strategy based on dynamic priority

    Institute of Scientific and Technical Information of China (English)

    巩思亮; 左秀婷; 梁庆伟; 邢涛

    2012-01-01

    针对μC/OS-Ⅱ仅支持高优先级独占内核,不支持任务时间片轮转调度的缺陷,提出了一种基于动态优先级方案的时间片轮转任务调度策略.该方案在没有改变内核源代码的前提下,仅在应用层面就能实现任务的时间片轮转调度,具有安全可靠、简单实用的特点.%To solve the problem that the kernel of μC/OS-Ⅱ does not support the round robin scheduling, a time slice rotation task scheduling strategy based on dynamic priority is proposed. The strategy realizes the task scheduling based on time slice rotation in the application level without changing the kernel source code. The analysis and experiment show that the strategy has the advaiages of safety, reliability, simpleness and practicability.

  9. 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.

  10. Medial superior olivary neurons receive surprisingly few excitatory and inhibitory inputs with balanced strength and short-term dynamics.

    Science.gov (United States)

    Couchman, Kiri; Grothe, Benedikt; Felmy, Felix

    2010-12-15

    Neurons in the medial superior olive (MSO) process microsecond interaural time differences, the major cue for localizing low-frequency sounds, by comparing the relative arrival time of binaural, glutamatergic excitatory inputs. This coincidence detection mechanism is additionally shaped by highly specialized glycinergic inhibition. Traditionally, it is assumed that the binaural inputs are conveyed by many independent fibers, but such an anatomical arrangement may decrease temporal precision. Short-term depression on the other hand might enhance temporal fidelity during ongoing activity. For the first time we show that binaural coincidence detection in MSO neurons may require surprisingly few but strong inputs, challenging long-held assumptions about mammalian coincidence detection. This study exclusively uses adult gerbils for in vitro electrophysiology, single-cell electroporation and immunohistochemistry to characterize the size and short-term plasticity of inputs to the MSO. We find that the excitatory and inhibitory inputs to the MSO are well balanced both in strength and short-term dynamics, redefining this fastest of all mammalian coincidence detector circuits.

  11. 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.

  12. 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...

  13. 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.

  14. 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…

  15. Task assignment and coaching

    NARCIS (Netherlands)

    Dominguez-Martinez, S.

    2009-01-01

    An important task of a manager is to motivate her subordinates. One way in which a manager can give incentives to junior employees is through the assignment of tasks. How a manager allocates tasks in an organization, provides information to the junior employees about his ability. Without coaching fr

  16. 操作机器人轴孔装配的行为动力学控制策略%Dynamics of Behavior Control Strategy in Peg-in-hole Assembly Task of Manipulator

    Institute of Scientific and Technical Information of China (English)

    魏明明; 傅卫平; 蒋家婷; 杨世强; 王雯

    2015-01-01

    The theory of mobile robot behavioral dynamics is extended to three-dimensional space of manipulator, and applied to peg-in-hole assembly task. The assembly process is divided into the trend toward assembly target and assembly phase. In the phase of trend toward assembly target, the dynamic model of target acquisition and obstacle avoidance are established respectively, and these two kinds of behavior constitute a overall coupling and competitive robot dynamics model. In assembly phase, the posture adjustment dynamic model is established and the lateral error formula is deduced. Throughout the assembly process, the use of macro/micro platform and visual/force servo, posture control is carried out on the shaft, make it meet the assembly condition. Simulation and experimental results show that, under the control of the dynamics equation, the end-effector while avoiding obstacles, safe and effective to reach the target assembly, successfully completed the peg-in-hole assembly, demonstrating the effectiveness of the proposed method.%将移动机器人行为动力学理论扩展到操作机器人三维空间,并应用到机器人轴孔装配中。把轴孔装配过程分为趋向装配目标阶段和装配阶段。在趋向装配目标阶段,分别建立趋向装配目标点和避障的行为动力学模型,并将两种行为耦合构成机器人整体的竞争动力学模型;在装配阶段,建立末端执行器姿态调整动力学模型,并推导了侧向误差计算公式;在整个装配过程,利用宏/微平台和视觉/力觉伺服,对轴进行位姿调整,使其满足装配条件。仿真和试验结果表明:在行为动力学方程的控制下,末端执行器在避开障碍物的同时,安全有效地到达装配目标点,顺利完成轴孔装配,证明方法的有效性。

  17. FLOAT Project - Task 1

    DEFF Research Database (Denmark)

    Marchalot, Tanguy; Kofoed, Jens Peter; Sørensen, Eigil V.

    The objective of the FLOAT project is to study the reliability of high-performance fibre-reinforced concrete, also known as Compact Reinforced Composite (CRC), for the floats of wave energy converters. In order to reach commercial breakthrough, wave energy converters need to achieve a lower price.......com, 2011). CRC floats could be a very cost-effective technology with enhanced loading capacity and environmental resistance, and very low maintenance requirements, affecting directly the final energy price. The project involves DEXA Wave Energy Ltd, Wave Star A/S, Aalborg University and Hi-Con A....../S. It is divided in 4 tasks: Task 1: Preliminary float design and economic considerations Task 2: Material characteristics Task 3: Preliminary experiences Task 4: The importance for wave energy The present report covers Task 1....

  18. 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.

  19. 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.

  20. 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.

  1. Adaptive Task-Space Cooperative Tracking Control of Networked Robotic Manipulators Without Task-Space Velocity Measurements.

    Science.gov (United States)

    Liang, Xinwu; Wang, Hesheng; Liu, Yun-Hui; Chen, Weidong; Hu, Guoqiang; Zhao, Jie

    2016-10-01

    In this paper, the task-space cooperative tracking control problem of networked robotic manipulators without task-space velocity measurements is addressed. To overcome the problem without task-space velocity measurements, a novel task-space position observer is designed to update the estimated task-space position and to simultaneously provide the estimated task-space velocity, based on which an adaptive cooperative tracking controller without task-space velocity measurements is presented by introducing new estimated task-space reference velocity and acceleration. Furthermore, adaptive laws are provided to cope with uncertain kinematics and dynamics and rigorous stability analysis is given to show asymptotical convergence of the task-space tracking and synchronization errors in the presence of communication delays under strongly connected directed graphs. Simulation results are given to demonstrate the performance of the proposed approach.

  2. Anterior medial prefrontal cortex exhibits activation during task preparation but deactivation during task execution.

    Directory of Open Access Journals (Sweden)

    Hideya Koshino

    Full Text Available BACKGROUND: The anterior prefrontal cortex (PFC exhibits activation during some cognitive tasks, including episodic memory, reasoning, attention, multitasking, task sets, decision making, mentalizing, and processing of self-referenced information. However, the medial part of anterior PFC is part of the default mode network (DMN, which shows deactivation during various goal-directed cognitive tasks compared to a resting baseline. One possible factor for this pattern is that activity in the anterior medial PFC (MPFC is affected by dynamic allocation of attentional resources depending on task demands. We investigated this possibility using an event related fMRI with a face working memory task. METHODOLOGY/PRINCIPAL FINDINGS: Sixteen students participated in a single fMRI session. They were asked to form a task set to remember the faces (Face memory condition or to ignore them (No face memory condition, then they were given 6 seconds of preparation period before the onset of the face stimuli. During this 6-second period, four single digits were presented one at a time at the center of the display, and participants were asked to add them and to remember the final answer. When participants formed a task set to remember faces, the anterior MPFC exhibited activation during a task preparation period but deactivation during a task execution period within a single trial. CONCLUSIONS/SIGNIFICANCE: The results suggest that the anterior MPFC plays a role in task set formation but is not involved in execution of the face working memory task. Therefore, when attentional resources are allocated to other brain regions during task execution, the anterior MPFC shows deactivation. The results suggest that activation and deactivation in the anterior MPFC are affected by dynamic allocation of processing resources across different phases of processing.

  3. 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…

  4. 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...

  5. 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 fragme......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......, 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...

  6. 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-...

  7. Task difficulty in mental arithmetic affects microsaccadic rates and magnitudes.

    Science.gov (United States)

    Siegenthaler, Eva; Costela, Francisco M; McCamy, Michael B; Di Stasi, Leandro L; Otero-Millan, Jorge; Sonderegger, Andreas; Groner, Rudolf; Macknik, Stephen; Martinez-Conde, Susana

    2014-01-01

    Microsaccades are involuntary, small-magnitude saccadic eye movements that occur during attempted visual fixation. Recent research has found that attention can modulate microsaccade dynamics, but few studies have addressed the effects of task difficulty on microsaccade parameters, and those have obtained contradictory results. Further, no study to date has investigated the influence of task difficulty on microsaccade production during the performance of non-visual tasks. Thus, the effects of task difficulty on microsaccades, isolated from sensory modality, remain unclear. Here we investigated the effects of task difficulty on microsaccades during the performance of a non-visual, mental arithmetic task with two levels of complexity. We found that microsaccade rates decreased and microsaccade magnitudes increased with increased task difficulty. We propose that changes in microsaccade rates and magnitudes with task difficulty are mediated by the effects of varying attentional inputs on the rostral superior colliculus activity map.

  8. 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.

  9. Energy Efficient Task Light

    DEFF Research Database (Denmark)

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

    2014-01-01

    The objectives of this work is to develop a task light for office lighting that fulfils the minimum requirements of the European standard EN12464 - 1 : Light and lighting – Lighting of work places, Part 1: Indoor workplaces and the Danish standard DS 700 : Lys og belysning I arbejdsrum , or more...... specifically the requirements that apply to the work area and the immediate surrounding area. By providing a task light that fulfils the requirements for task lighting and the immediate surrounding area, the general lighting only needs to provide the illuminance levels required for background lighting...... 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...

  10. 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...

  11. Performing Task Integration

    DEFF Research Database (Denmark)

    Elkjaer, Bente; Nickelsen, Niels Christian Mossfeldt

    . 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...... away with differences regarding task definitions and working conditions as well as professional knowledge hierarchies and responsibilities for parts and wholes....

  12. Task Switching in a Hierarchical Task Structure: Evidence for the Fragility of the Task Repetition Benefit

    Science.gov (United States)

    Lien, Mei-Ching; Ruthruff, Eric

    2004-01-01

    This study examined how task switching is affected by hierarchical task organization. Traditional task-switching studies, which use a constant temporal and spatial distance between each task element (defined as a stimulus requiring a response), promote a flat task structure. Using this approach, Experiment 1 revealed a large switch cost of 238 ms.…

  13. 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.

  14. 异构分布式实时系统中对具有前后依赖关系任务的基于动态可变调度距离容错调度算法%A Fault Tolerant Scheduling Algorithm Based on Dynamical Distance for Precedence Constrained Task in Hard Real Time Heterogeneous Distributed System

    Institute of Scientific and Technical Information of China (English)

    刘栋; 孟庆鑫; 潘哲

    2014-01-01

    In existed primary/backup fault-tolerant scheduling algorithms almost required that tasks are independent, but in fact tasks in many distributed system are dependent. A novel fault tolerant scheduling algorithm based on dynamical distance between primary and backup tasks was proposed. By this algorithm, according to difference between earliest start time and latest start time between tasks, put the backup task in different position in task queue, and tasks can overlap with each other obey proposed rules. The proposed algorithm(Based on Dynamical Distance fault tolerant scheduling algorithm) improved the last task’s earliest finished time , also improved the task’s guarantee ratio at the same time improve system’s reliability, and the critical path task have priority so that decrease fault tolerant overload .The result of the simulation shows that the algorithm is effective.%目前的主副版本容错调度算法大多没有考虑任务间的前后依赖关系,但实际中很多任务是具有前后依赖关系的。本文提出了一种基于主副版本动态可变调度距离的任务容错调度算法,该技术通过比较任务间的最晚开始执行时间与最早开始执行时间的差值,安排任务副版本的调度,并且基于此设计了可用于具有前后依赖关系任务调度可重叠技术。本文提出的基于动态可变调度距离的容错调度算法在尽可能让任务最早完成的情况下,提高系统的可靠性,并且优先调度关键路径任务,降低了系统的容错开销。最后通过实验证明本文算法的有效性和优异性。

  15. 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

  16. 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

  17. 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

  18. A self-organizing model for task allocation via frequent task quitting and random walks in the honeybee.

    Science.gov (United States)

    Johnson, Brian R

    2009-10-01

    Social insect colonies are able to quickly redistribute their thousands of workers between tasks that vary strongly in space and time. How individuals collectively track spatial variability is particularly puzzling because bees have access only to local information. This work presents and tests a model showing how honeybees solve their fundamental within-nest spatial task-allocation problem. The algorithm, which is self-organizing and derived from empirical studies, couples two processes with opposing effects. Frequent task quitting, followed by patrols, during which bees are insensitive to task stimuli, serves to randomize individual location throughout the nest without reference to variation in task demand, while a foraging-for-work-like mechanism provides the opposing force of localizing individuals to areas of high task demand. This simple model is shown to generate sophisticated patterns of task allocation. It allocates bees to tasks in proportion to their demand, independent of their spatial distribution in the nest, and also reallocates labor in response to temporal changes in task demand. Finally, the model shows that task-allocation patterns at the colony level do not reflect colonies allocating particular individuals to tasks. In contrast, they reflect a dynamic equilibrium of workers switching between tasks and locations in the nest.

  19. Directional dependence of binaural loudness

    DEFF Research Database (Denmark)

    Ellermeier, Wolfgang; Sivonen, Ville Pekka

    2006-01-01

    Even though there is a vast body of literature on spatial hearing, little is known on how the location of a sound source affects its loudness. The pertinent research on head-related transfer functions(HRTFs) primarily deals with issues of localization and spatial discriminability. The literature ...

  20. 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.

  1. 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.

  2. 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.

  3. Reservation-based feedback scheduling of MPC tasks

    Institute of Scientific and Technical Information of China (English)

    Zhou Pingfang; Xie Jianying

    2007-01-01

    A reservation-based feedback scheduling (FS-CBS) of a set of model predictive control (MPC) tasks is presented to optimize the global control performance subject to limited computational resource. Implemented as anytime algorithm,MPC task allows computation time to be traded for control performance. Each MPC task is assigned with a constant bandwidth server (CBS), whose reserved processor time is adjusted dynamically. The FS-CBS is shown robust against the varying of execution time of MPC tasks at runtime. Simulation results illustrate its effectiveness.

  4. 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

  5. Pain Management Task Force

    Science.gov (United States)

    2010-05-01

    Additionally, the Task Force consulted with the Samueli Institute, a non-profit research organization that supports the scientific investigation of healing...and its role in medicine and health care. The Samueli Institute has been working on several research projects related to military and Veterans’ pain... Samueli communication). The CAM subgroup of the TF studied the issues surrounding credentialing and licensing of CAM providers. The tiered

  6. Features or tasks?

    DEFF Research Database (Denmark)

    Heilesen, Simon

    In this paper for the Workshop on Human-computer interaction and e-learning, NordiCHI 2002, the author argues that in developing innovative E-learning systems, especially if constructivist pedagogy is to be applied, it will be useful to model the user interface on the often complex tasks...... that the user has to perform rather than just focusing on technical features (and adapting system use to them)....

  7. Gap Task Force

    CERN Document Server

    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...

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. Principles of Communicative Task Design.

    Science.gov (United States)

    Nunan, David

    The use of the learning task as a basic planning and instructional tool for communicative second language instruction is discussed, and considerations and procedures for designing such tasks are outlined. A task is defined as a piece of classroom work that involves learners in comprehending, manipulating, producing, or interacting in the target…

  13. TASK: Let's Have a Party!

    Science.gov (United States)

    Rees, James

    2012-01-01

    In this article, the author describes a creative way to demystify contemporary art for students. TASK is artist Oliver Herring's creation, where participants actively interpret instructions found on little pieces of paper--what he calls "tasks." An art classroom has all the key ingredients for a TASK event: (1) people; (2) materials; (3) space;…

  14. 双耳听力对称性的急性耳鸣诊治研究%Research of Diagnosis and Treatment for Acute Tinnitus with Binaural Hearing Symmetry

    Institute of Scientific and Technical Information of China (English)

    杨栋

    2014-01-01

    目的:探讨双耳听力对称性的急性耳鸣临床诊治。方法对我院于2011年7月至2013年5月收治的22例双耳听力对称性急性耳鸣患者、经纯音测听均为双耳听力正常患者,作为实验组;另外选取同期一般资料不存在显著差异的20例听力正常无耳鸣健康体检者作为对照组,分析和对比对照组和实验组的畸变产物耳声发射检查情况。结果实验组在1.00、2.00、4.00和8.00 kHz中的检出率均低于对照组,差异有统计学意义(P<0.05)。并且经治疗后,实验组除1.00 kHz外,其余频率点的耳声发射反应幅值明显要优于治疗前(P<0.05)。结论给予双耳听力对称性的急性耳鸣患者应用耳声发射检查,能够对患者的耳蜗病变情况进行尽早诊断和及时治疗,临床应用价值相对较高,值得进一步推广和使用。%Objective To explore the diagnosis and treatment for acute tinnitus with Binaural hearing symmetry. Methods From July 2011 to May 2013, 22 cases of Patients who were suffered from acute tinnitus with Binaural hearing symmetry and via the pure tone audiometer confirmed to be normal were divided into the experimental group;while selected 20 cases of patients with normal hearing and at the same period and no significant difference as the control group. Results The detection rate of the experimental group in 1.00 kHz,2.00 kHz,4.00 kHz and 8.00 kHz were all lower than the control group, and the difference were statistically significant (P<0.05). And after the treatment, the amplitude frequency points of oases reaction in the experimental group were all better than before except at 1.00 kHz. Conclusion Giving the binaural hearing symmetry of acute tinnitus patients an application of ear acoustic emission inspection can help diagnosis early and timely treatment. And this inspection can obtain higher clinical value, and it is worthy of further promotion.

  15. Gun Dynamics Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Gun Dynamics Laboratory is a research multi-task facility, which includes two firing bays, a high bay area and a second floor laboratory space. The high bay area...

  16. 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

  17. 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’.

  18. LeoTask: a fast, flexible and reliable framework for computational research

    OpenAIRE

    Zhang, Changwang; Zhou, Shi; Chain, Benjamin M

    2015-01-01

    LeoTask is a Java library for computation-intensive and time-consuming research tasks. It automatically executes tasks in parallel on multiple CPU cores on a computing facility. It uses a configuration file to enable automatic exploration of parameter space and flexible aggregation of results, and therefore allows researchers to focus on programming the key logic of a computing task. It also supports reliable recovery from interruptions, dynamic and cloneable networks, and integration with th...

  19. Modeling Network Interdiction Tasks

    Science.gov (United States)

    2015-09-17

    cut. To solve the problem, Wood reformulated the follower (max-flow) problem using its dual with the decision variable for the interdiction of arcs, γij...to remove nodes (and their outgoing arcs), so as to minimize the maximal s-t flow. The solution approach was to reformulate the follower problem so all...package is a suite of functions encoded in the Python language “for the creation, manipulation, and study of the structure, dynamics, and functions

  20. 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

  1. 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.

  2. Task-Space Iterative Learning for Redundant Robotic Systems: Existence of a Task-Space Control and Convergence of Learning

    Science.gov (United States)

    Arimoto, Suguru; Sekimoto, Masahiro; Kawamura, Sadao

    This paper presents a feasibility study of iterative learning control for a class of redundant multi-joint robotic systems when a desired motion trajectory is specified in task-space with less dimension than that of joint space. First, it is shown that if the desired trajectory described in task-space for a time interval t ∈ [0,T] is twice continuously differentiable then a unique control signal describable in task-space exists despite of the system joint-redundancy. Second, a learning control update law is constructed through transpose of the Jacobian matrix of task-space coordinates with respect to joint coordinates by using measured data of motion trajectories in task-space. Third, the convergence of trajectory trackings through iterative learning is proved theoretically on the basis of original nonlinear robot dynamics in joint space.

  3. 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....... The rostering process is non-trivial and especially when service is required around the clock, rostering may involve considerable effort from a designated planner. Therefore, in order to minimize costs and overstaffing, to maximize the utilization of available staff, and to ensure a high level of satisfaction...... among the employees, sophisticated scheduling methods are required. When approaching the day of operation, the detail level of the planning becomes finer. With a given allocation of shifts to employees, the focus is turned to tasks scheduling within those shifts. The objective is to assign as much work...

  4. 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.

  5. Efficient human hand kinematics for manipulation tasks

    OpenAIRE

    Cobos Guzmán, Salvador; Ferre Perez, Manuel; Sanchez-Uran Gonzalez, Miguel Angel; Ortego la Moneda, Javier; Peña, César

    2008-01-01

    This work is focused on obtaining efficient human hand models that are suitable for manipulation tasks. A 24 DoF kinematic model of the human hand is defined to realistic movements. This model is based on the human skeleton. Dynamic and Static constraints have been included in order to improve the movement realism. Two simplified hand models with 9 and 6 DoF have been developed according to the constraints predefined. These simplified models involve some errors in reconstructing the hand post...

  6. Caffeine improves anticipatory processes in task switching

    NARCIS (Netherlands)

    Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard

    2006-01-01

    We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials (e

  7. Putting Mathematical Tasks into Context

    Science.gov (United States)

    Nagle, Courtney R.; Styers, Jodie L.

    2015-01-01

    Although many factors affect students' mathematical activity during a lesson, the teacher's selection and implementation of tasks is arguably the most influential in determining the level of student engagement. Mathematical tasks are intended to focus students' attention on a particular mathematical concept and it is the careful developing and…

  8. Creativity, Overinclusion, and Everyday Tasks

    Science.gov (United States)

    Ottemiller, Dylan D.; Elliott, Colette Seter; Giovannetti, Tania

    2014-01-01

    This study examined relations between creative thinking and performance on routine, everyday tasks. Results were considered in light of past research on the putative relation between creativity and schizophrenia/psychotic thinking. Thirty healthy undergraduates completed the Alternative Uses Task, a measure of divergent thinking, and the 2 × 3…

  9. 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.

  10. 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

  11. 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

  12. EFFORTS Sub-task report on task 4.1: Experimental Techniques

    DEFF Research Database (Denmark)

    Andreasen, Jan Lasson; Bay, Niels

    1998-01-01

    Task 4.1 is a sub-task of task 4: Physical modelling validation. In sub-task 4.1 the existing experimental techniques has been conditioned to the tasks ahead in physical modelling.......Task 4.1 is a sub-task of task 4: Physical modelling validation. In sub-task 4.1 the existing experimental techniques has been conditioned to the tasks ahead in physical modelling....

  13. Emotional priming effects during Stroop task performance.

    Science.gov (United States)

    Hart, Sarah J; Green, Steven R; Casp, Michael; Belger, Aysenil

    2010-02-01

    The ability to make decisions within an emotional context requires a balance between two functionally integrated neural systems that primarily support executive control and affective processing. Several studies have demonstrated effects of emotional interference presented during an ongoing cognitive task, but it is unclear how activating the emotional circuitry prior to a cognitive task may enhance or disrupt the executive system. In this study we used fMRI to examine the effects of emotional priming on executive processing during a number Stroop task. Our results indicated that during trials with less executive requirements, there was a greater aversive emotional attenuation effect in a network of regions including the ventrolateral prefrontal cortex (vlPFC), insula and cingulate gyrus. This attenuation effect was counteracted during trials with increased executive demand, suggesting that while pre-activation of the emotional system may lead to an automatic attenuation of activity in multiple regions, requirements for executive function may override the aversive emotional attenuation effect. Furthermore, this override effect was found to be associated with faster reaction times during executive processing. These findings demonstrate that activity in the vlPFC, cingulate and insula is dynamically adjusted in order to optimize performance, and illustrate the importance of the timing of each system's engagement in determining how competing cognitive and emotional information is processed.

  14. 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.

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

    Directory of Open Access Journals (Sweden)

    Shin-Yi Chiou

    Full Text Available 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.

  16. 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.

  17. Thalamocortical rhythms during a vibrotactile detection task

    Science.gov (United States)

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

    2014-01-01

    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. PMID:24733899

  18. 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.

  19. Task Analyses for Difficult-to-Assess Collective Tasks

    Science.gov (United States)

    2014-02-01

    pronunciation and use of common phrases of the local dialect likely to be of utility during the KLE. Rehearse mission with KLE team. Coordinate...concurrently teaching individual crew, leader, and collective skills. Demonstrate to HN personnel the execution of each task using a step-by-step process...training when possible by concurrently teaching individual crew, leader, and collective skills. Demonstrate to HN personnel the execution of each task

  20. 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...

  1. Task-dependent modulation of oscillatory neural activity during movements

    DEFF Research Database (Denmark)

    Herz, D. M.; Christensen, M. S.; Reck, C.

    2011-01-01

    Neural oscillations in different frequency bands have been observed in a range of sensorimotor tasks and have been linked to coupling of spatially distinct neurons. The goal of this study was to detect a general motor network that is activated during phasic and tonic movements and to study the task......-dependent modulation of frequency coupling within this network. To this end we recorded 122-multichannel EEG in 13 healthy subjects while they performed three simple motor tasks. EEG data source modeling using individual MR images was carried out with a multiple source beamformer approach. A bilateral motor network...... connecting frontal, cerebellar and central motor regions, was consistently activated throughout the motor tasks. Quantification of observed spectral responses using dynamic causal modeling revealed strong coupling in the c-band (30–48 Hz) between frontal and central motor regions when a slow finger movement...

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. Polishing a Data Task: Seeking Better Assessment.

    Science.gov (United States)

    Zawojewski, Judith S.

    1996-01-01

    Shares a teacher's stages of selecting and revising a performance-assessment task focusing on data handling. Discusses selection and revision criteria, examining student work, reflecting on the task, and revising the final task. (MKR)

  7. Tasks and activities to enhance technological Pedagogical Mathematical Content Knowledge of teachers

    OpenAIRE

    Powell, Arthur B.

    2016-01-01

    From a sociocultural perspective, we examine activities generated by genres of tasks to understand how the tasks shape teachers knowledge of technology and mathematical content for teaching. The tasks and activities come from a professional development project that engages the cyberlearning system, Virtual Math Teams with GeoGebra. Working in teams, teachers enhance their understanding of dynamic geometry and how to engage in productive mathematical discussion. We theorize and discuss princip...

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

    OpenAIRE

    FATEMI, Afsaneh; Zamanifar, Kamran; NEMATBAKHSH, Naser

    2014-01-01

    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. Building Task-Oriented Applications: An Introduction to the Legion Programming Paradigm

    Science.gov (United States)

    2015-02-01

    parallel programming design and development in a task-oriented fashion and, as of this writing, is the only one to address this paradigm dynamically... fashion , providing a set of tasks to execute on defined logical regions in the code.5,6,10 These tasks are structured in a hierarchy and will bind...particular the extension of this work to include the Fast Multipole Method (FMM) of the n-body problem is an interesting direction. FMM is currently

  10. Task-irrelevant perceptual expertise.

    Science.gov (United States)

    Wong, Yetta K; Folstein, Jonathan R; Gauthier, Isabel

    2011-12-05

    Perceptual learning (PL) and perceptual expertise (PE) are two fields of visual training studies that investigate how practice improves visual performance. However, previous research suggests that PL can be acquired in a task-irrelevant manner while PE cannot and that PL is highly specific to the training objects and conditions while PE generalizes. These differences are difficult to interpret since PL and PE studies tend to differ on multiple dimensions. We designed a training study with novel objects to compare PL and PE while varying only the training task, such that the training objects, visual field, training duration, and type of learning assessment were kept constant. Manipulations of the training task sufficed to produce the standard effects obtained in PE and PL. In contrast to prior studies, we demonstrated that some degree of PE can be acquired in a task-irrelevant manner, similar to PL. Task-irrelevant PE resulted in similar shape matching ability compared to the directly trained PE. In addition, learning in both PE and PL generalizes to different untrained conditions, which does not support the idea that PE generalizes while PL is specific. Degrees of generalization can be explained by considering the psychological space of the stimuli used for training and the test of transfer.

  11. A System-level Simulation Framework for Evaluating Task Migration in MPSoCs

    NARCIS (Netherlands)

    Quan, W.; Pimentel, A.D.

    2014-01-01

    Task migration is the transfer of the execution of a process (task) from one processing element to another. It originates from the massive deployment of distributed systems in the parallel computing field to enable dynamic load distribution, fault resilience and to enhance data access locality. With

  12. 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.

  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. Compensatory mechanisms underlie intact task-switching performance in schizophrenia.

    Science.gov (United States)

    Jamadar, S; Michie, P; Karayanidis, F

    2010-04-01

    Individuals with schizophrenia tend to perform poorly on many measures of cognitive control. However, recent task-switching studies suggest that they show intact task-switching performance, despite the fact that the regions involved in task-switching are known to be structurally and functionally impaired in the disorder. Behavioral, event-related potential (ERP) and functional magnetic resonance imaging (fMRI) measures were used to compare the temporal and spatial dynamics of task-switching performance in individuals with schizophrenia and controls. Consistent with previous studies, reaction time (RT) switch cost and its reduction with anticipatory preparation did not differ between groups. There were also no group differences on cue-locked ERP components associated with anticipatory preparation processes. However, both stimulus- and response-locked ERPs were significantly disrupted in schizophrenia, suggesting difficulty with task-set implementation. fMRI analyses indicated that individuals with schizophrenia showed hyperactivity in the dorsolateral prefrontal cortex and posterior parietal cortex. RT-fMRI and ERP-fMRI associations suggested that individuals with schizophrenia employ compensatory mechanisms to overcome difficulties in task-set implementation and thereby achieve the same behavioral outcomes as controls.

  15. 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.

  16. 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

  17. Novice supervisors' tasks and training

    DEFF Research Database (Denmark)

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

    2012-01-01

    Questionnaire covering a wide range of items on professional development, experience, and practice. In this paper we focus on background data (experience, training and practice), specifically the tasks and training of the respondents as novice supervisors. The results show, that a majority of novice supervisors...... 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. 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."

  19. Task descriptions versus use cases

    DEFF Research Database (Denmark)

    Lauesen, Søren; Kuhail, Mohammad Amin

    2011-01-01

    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...

  20. Use cases versus task descriptions

    DEFF Research Database (Denmark)

    Lauesen, Søren; Kuhail, Mohammad Amin

    2011-01-01

    to specify require-ments for the same project: Acquire a new system to support a hotline. [Princi-pal ideas/results] Among the 15 replies, eight used traditional use cases that specified a dialog between users and system. Seven used a related technique, task description, which specified the customer's needs...

  1. Task-Based Writing Instruction

    Science.gov (United States)

    Bantis, Alexandros

    2010-01-01

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

  2. 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...

  3. Scientists and the Selection Task.

    Science.gov (United States)

    Griggs, Richard A.; Ransdell, Sarah E.

    1986-01-01

    Presents findings of a study of scientists on the Wason four-card selection task, finding little understanding of the effect of disconfirmatory data in assessing conditionals. Found performance influenced by problem content. Explains performance as memory-cueing plus reasoning-by-analogy. (JM)

  4. On the Tasks of Translation

    Institute of Scientific and Technical Information of China (English)

    王晓菊

    2012-01-01

      Many linguists, translators, and theorists have been arguing over the approaches on translation. While putting these into use a translator may experience many pleasure and problems as well. The purpose of this article is to discuss the tasks of translation and the way of choosing the proper translation approaches according to the author’s own experience of practice.

  5. 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…

  6. 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…

  7. The Importance of Context in Task Selection

    Science.gov (United States)

    Weiland, Travis

    2017-01-01

    Context is at the core of any statistical investigation, yet many statistics tasks barely require students to go beyond superficial consideration of the contexts the tasks are situated in. In this article, I discuss a framework for evaluating the level of interaction with context a task requires of students and how to modify tasks to increase the…

  8. Who multi-tasks and why? Multi-tasking ability, perceived multi-tasking ability, impulsivity, and sensation seeking.

    Directory of Open Access Journals (Sweden)

    David M Sanbonmatsu

    Full Text Available The present study examined the relationship between personality and individual differences in multi-tasking ability. Participants enrolled at the University of Utah completed measures of multi-tasking activity, perceived multi-tasking ability, impulsivity, and sensation seeking. In addition, they performed the Operation Span in order to assess their executive control and actual multi-tasking ability. The findings indicate that the persons who are most capable of multi-tasking effectively are not the persons who are most likely to engage in multiple tasks simultaneously. To the contrary, multi-tasking activity as measured by the Media Multitasking Inventory and self-reported cell phone usage while driving were negatively correlated with actual multi-tasking ability. Multi-tasking was positively correlated with participants' perceived ability to multi-task ability which was found to be significantly inflated. Participants with a strong approach orientation and a weak avoidance orientation--high levels of impulsivity and sensation seeking--reported greater multi-tasking behavior. Finally, the findings suggest that people often engage in multi-tasking because they are less able to block out distractions and focus on a singular task. Participants with less executive control--low scorers on the Operation Span task and persons high in impulsivity--tended to report higher levels of multi-tasking activity.

  9. 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...

  10. Evaluating the Semantic Web: A Task-Based Approach

    Science.gov (United States)

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

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

  11. EEG based topography analysis in string recognition task

    Science.gov (United States)

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

    2017-03-01

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

  12. Evolution of Task Partitioning in Swarm Robotics

    OpenAIRE

    Ferrante, Eliseo,; Duenez-Guzman, E.; Turgut, A. E.; Wenseleers, Tom

    2013-01-01

    International audience; Task-partitioning refers to the process whereby a task is divided into two or more sub-tasks. Through task partitioning both efficiency and effectiveness can be improved provided the right environmental conditions. We synthesize self-organized task partitioning behaviors for a swarm of mobile robots using artificial evolution. Through validation experiments, we show that the synthesized behaviors exploits behavioral specialization despite being based on homogeneous ind...

  13. Individual Differences in Secondary Task Performance.

    Science.gov (United States)

    1980-09-01

    task similar to that used by Atkinson and Shiffrin (1968). The spatial task in- volved holding in memory a random pattern of plus signs. In all cases...may serve to attenuate the easy-to-hard correlation. I *1,~ __ __ _ Secondary Task Performance 33 References Atkinson , R. C., & Shiffrin , R. M. Human...aIde if nec.eaar, and Identify by block number) ability, attention, dual task, information processing, individual differences memory , secondary task

  14. EMG feedback tasks reduce reflexive stiffness during force and position perturbations.

    Science.gov (United States)

    Forbes, Patrick A; Happee, Riender; van der Helm, Frans C T; Schouten, Alfred C

    2011-08-01

    Force and position perturbations are widely applied to identify muscular and reflexive contributions to posture maintenance of the arm. Both task instruction (force vs. position) and the inherently linked perturbation type (i.e., force perturbations-position task and position perturbations-force tasks) affect these contributions and their mutual balance. The goal of this study is to explore the modulation of muscular and reflexive contributions in shoulder muscles using EMG biofeedback. The EMG biofeedback provides a harmonized task instruction to facilitate the investigation of perturbation type effects irrespective of task instruction. External continuous force and position perturbations with a bandwidth of 0.5-20 Hz were applied at the hand while subjects maintained prescribed constant levels of muscular co-activation using visual feedback of an EMG biofeedback signal. Joint admittance and reflexive impedance were identified in the frequency domain, and parametric identification separated intrinsic muscular and reflexive feedback properties. In tests with EMG biofeedback, perturbation type (position and force) had no effect on joint admittance and reflexive impedance, indicating task as the dominant factor. A reduction in muscular and reflexive stiffness was observed when performing the EMG biofeedback task relative to the position task. Reflexive position feedback was effectively suppressed during the equivalent EMG biofeedback task, while velocity and acceleration feedback were both decreased by approximately 37%. This indicates that force perturbations with position tasks are a more effective paradigm to investigate complete dynamic motor control of the arm, while EMG tasks tend to reduce the reflexive contribution.

  15. 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.

  16. Novel Peritonsillar Abscess Task Simulator.

    Science.gov (United States)

    Taylor, Steven R; Chang, C W David

    2014-07-01

    The management of peritonsillar abscesses is a skill developed early in residency training. Although drainage is not technically complicated, the procedure is intimidating to the neophyte. Task simulators have become increasingly common to provide training opportunities in a controlled environment. The authors designed a peritonsillar abscess simulator using a latex moulage of the oral cavity and other common materials. Twelve medical professionals of various levels of experience were instructed to expose, anesthetize, aspirate, and drain the simulated abscess. After completion, a questionnaire was completed by each volunteer. Initial impressions were positive that the model adequately replicated the tasks requisite for abscess drainage and was suitable as an instructional device. The initial construct cost was approximately 10 dollars, with disposables costing roughly 25 cents. Further research is under way to formally assess the simulator for face, content, and construct validity.

  17. Measuring Multi-tasking Ability

    Science.gov (United States)

    2003-07-01

    research. Table 2. Candidate MT Jobs Emergency Room Nurse Emergency Medical Technician Emergency Room Physician Intensive Care Nurse Floor Nurse Waitress ...the ICU and floor nurses, chefs, Army combat leaders, LCAC Craftmasters and LCAC Navigators who educated us about multi- tasking in the working world...different for intensive care nurses than for floor nurses. Hence, individuals were interviewed who had performed a variety of food preparation

  18. 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.

  19. 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.

  20. Simulation of Tasks Distribution in Horizontally Scalable Management System

    Science.gov (United States)

    Kustov, D.; Sherstneva, A.; Botygin, I.

    2016-08-01

    This paper presents an imitational model of the task distribution system for the components of territorially-distributed automated management system with a dynamically changing topology. Each resource of the distributed automated management system is represented with an agent, which allows to set behavior of every resource in the best possible way and ensure their interaction. The agent work load imitation was done via service query imitation formed in a system dynamics style using a stream diagram. The query generation took place in the abstract-represented center - afterwards, they were sent to the drive to be distributed to management system resources according to a ranking table.

  1. 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…

  2. 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...

  3. 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,......

  4. 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...

  5. 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...

  6. 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...

  7. ePartners for Dynamic Task Allocation and Coordination

    NARCIS (Netherlands)

    De Greef, T.

    2012-01-01

    This dissertation promotes a focus shift from automation extending human capabilities to automation partnering with the human. Highly automated systems tend to be incompatible with humans, leading to degradations in performance that may lead to serious problems in high-risk professional domains, suc

  8. 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.

  9. Modeling Dynamic Tactical Behaviors in Combatxxi using Hierarchical Task Networks

    Science.gov (United States)

    2014-06-01

    Simulation Office AI artificial intelligence BFTB Battles from the Bulge BT behavior tree CE command element CNA Center for Naval Analysis COA course of...an RTS game released in 2006 and set during the World War II (WWII) Greek Campaign. Battles from the Bulge (BFTB) was released in 2010 and “covers the...www.plannedassault.com/faqs [33] D. O’Connor. (2011, May.). Strategic War Game AI in Battles from the Bulge . AiGameDev. [Online]. Available: http

  10. 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.

  11. 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...... of individual program tasks and the data dependencies among these. This paper introduces two compiler directives which let programmers annotate source code with data dependencies among tasks. Compiler analysis overapproximates the actual dependencies among tasks. The directives help eliminate potential data...... 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...

  12. Synchronised and complementary coordination mechanisms in an asymmetric joint aiming task

    DEFF Research Database (Denmark)

    Skewes, Joshua Charles; Skewes, Lea; Michael, John

    2015-01-01

    ) strategies. These two mechanisms have been mostly studied independently, the former in the context of rhythmic tasks, and the latter in non-rhythmic tasks. However, people often balance these two strategies in real life social interactions, in order to achieve a joint goal more effectively. Here, our aim...... was to investigate how people may implicitly balance synchronisation and complementarity in a continuous joint aiming task. We asked dyads to synchronise the timing of their clicks between targets, while changing task constraints for one member of the dyad (i.e. different task difficulties) to asymmetrically perturb...... the continuous interaction. This allowed us to investigate how individuals implicitly negotiate complementary leader-follower dynamics to achieve synchronisation. We found that dyads flexibly switch from mutual to asymmetric adaptation given variations in task constraints. Specifically, our results show...

  13. Critical care nurses' information-seeking behaviour during an unfamiliar patient care task.

    Science.gov (United States)

    Newman, Kristine M; Doran, Diane

    2012-01-01

    Critical care nurses complete tasks during patient care to promote the recovery or maintain the health of their patients. These tasks can be routine or non-routine to the nurse. Non-routine tasks are characterized by unfamiliarity, requiring nurses to seek additional information from a variety of sources to effectively complete the tasks. Critical care units are dynamic environments where decisions are often made by nurses under stress and time pressure because patient status changes rapidly. A non-routine task (e.g., administration of an unfamiliar medication) to the critical care nurse can impact patient care outcomes (e.g., increased time to complete task has consequences for the patient). In this article, the authors discuss literature reviewed on nurses' information-seeking and explore an information-seeking conceptual model that will be used as a guide to examine the main concepts found through the empirical evidence.

  14. Robot Arm Control Exploiting Natural Dynamics

    Science.gov (United States)

    1999-06-01

    and the approach taken in this thesis is the role of the robot dynamics . In traditional control, the robot is viewed as a general purpose manipulator...robot, and the robot control enforces that command. The robot dynamics are generally ignored or canceled, and certainly do not play a part in how the...task is planned. The approach taken in this thesis is the opposite: the robot dynamics are crucial for the performance of the task as they determine

  15. Quality of Language and Purpose of Task: Patterns of Learners' Language on Two Oral Communication Tasks.

    Science.gov (United States)

    Bygate, Martin

    1999-01-01

    Examines the performance of Hungarian secondary school students on two types of unscripted tasks--an argument task and a narrative task. Focuses on grammatical patterns of learner language, and reports significant differences in the learners' performance. (Author/VWL)

  16. EFFORTS Sub-task report on task 4.2: Cold forming

    DEFF Research Database (Denmark)

    Andreasen, Jan Lasson; Christensen, Thomas Vennick; Bay, Niels

    1999-01-01

    Task 4.2 is a sub-task of task 4: Physical modelling validation. In sub-task 4.2 experimental analysis of cold forming as regards form filling, interface stresses and forces and moments using sof model materials have been carried out.......Task 4.2 is a sub-task of task 4: Physical modelling validation. In sub-task 4.2 experimental analysis of cold forming as regards form filling, interface stresses and forces and moments using sof model materials have been carried out....

  17. 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.

  18. U.S. Preventive Services Task Force

    Science.gov (United States)

    ... Public Comment In an effort to make the U.S. Preventive Services Task Force (USPSTF) recommendations clearer and ... Current as of: May 2016 Internet Citation: Home . U.S. Preventive Services Task Force. August 2016. https://www. ...

  19. 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....

  20. Binaural Tracking of Multiple Moving Sources

    Science.gov (United States)

    2006-01-01

    a minimum- phase filter and a pure delay line [27]. The motivation is that minimum-phase systems behave better than the raw measurements for...are set to 0 and a minimum- phase filter is then obtained by inverting the truncated cepstrum [29]. The time delay part is estimated as the mean of the...incidence is obtained by interpolating separately the minimum- phase filters and the time delays corresponding to neighboring entries in the HRTF

  1. Binaural processing by the gecko auditory periphery

    DEFF Research Database (Denmark)

    Christensen-Dalsgaard, Jakob; Tang, Ye Zhong; Carr, Catherine E

    2011-01-01

    of direct and indirect sound components at the eardrum. Best ITD and click delays match interaural transmission delays, with a range of 200-500μs. Inserting a mold in the mouth cavity blocks ITD and ILD sensitivity. Thus the neural response accurately reflects tympanic directionality, and most neurons...

  2. Binaural Sound Localization Using Neural Networks

    Science.gov (United States)

    1991-12-12

    by Brennan, involved the implementation of a neural network to model the ability of a bat to discriminate between a mealworm and an inedible object...locate, identify and capture airborne prey (6:2). The sonar returns were collected from the mealworms , spheres and disks at various rotations (90 to

  3. What Makes a Mathematical Task Interesting?

    Science.gov (United States)

    Nyman, Rimma

    2016-01-01

    The study addresses the question of what makes a mathematical task interesting to the 9th year students. Semi-structured interviews were carried out with 15 students of purposive selection of the 9th year. The students were asked to recall a task they found interesting and engaging during the past three years. An analysis of the tasks was made…

  4. A Task Is a Task Is a Task Is a Task... Or Is It? Researching Telecollaborative Teacher Competence Development--The Need for More Qualitative Research

    Science.gov (United States)

    Müller-Hartmann, Andreas

    2016-01-01

    The concept of task has become central not only to an understanding of language learning per se, but also to the design and research of Online Intercultural Exchanges (OIEs). While research on the design of tasks in OIEs has been very productive, we still lack insights into how teachers develop competences in task design on the micro-level.…

  5. Imagining Mathematics Teaching via Scripting Tasks

    Science.gov (United States)

    Zazkis, Rina; Sinclair, Nathalie

    2013-01-01

    We discuss an innovative task used in teacher education--Lesson Play--that involves presenting a lesson in the form of an interaction between a teacher and students. We describe the motivation for the development of this task and, through specific examples, describe the iterative design process in which the task was refined and improved. We…

  6. Task Complexity and Second Language Narrative Discourse.

    Science.gov (United States)

    Robinson, Peter

    1995-01-01

    Examines differences in oral narrative discourse of adult second-language learners of English on narrative tasks simulating the ability to describe events in the Here-and-Now versus the There-and-Then. Results indicate that complex tasks elicit less fluent, but more accurate and complex narration than do simpler tasks. (90 references) (Author/CK)

  7. 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).

  8. Modeling Robot Dynamic Performance for Endpoint Force Control

    Science.gov (United States)

    1988-08-01

    Task Dynamics 55 2.5.1 The Dynamic Workpiece Model 55 2.5.2 Adding Robot Dynamics 56 2.5.3 Adding Actuator Dynamics 56 Tabie I o iiau 6 2.6 Grip...motion control system. Robot dynamics couple with the task dynamics in a very complex way. When the robot makes contact with the environment, the impact...robot flexibility or actuator dynamics. 2.5.2 Adding Robot Dynamics Figure 2.29 shows the robot now represented by two lumped masses, as in the robot

  9. 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.

  10. TASK-1 and TASK-3 may form heterodimers in human atrial cardiomyocytes.

    Science.gov (United States)

    Rinné, Susanne; Kiper, Aytug K; Schlichthörl, Günter; Dittmann, Sven; Netter, Michael F; Limberg, Sven H; Silbernagel, Nicole; Zuzarte, Marylou; Moosdorf, Rainer; Wulf, Hinnerk; Schulze-Bahr, Eric; Rolfes, Caroline; Decher, Niels

    2015-04-01

    TASK-1 channels have emerged as promising drug targets against atrial fibrillation, the most common arrhythmia in the elderly. While TASK-3, the closest relative of TASK-1, was previously not described in cardiac tissue, we found a very prominent expression of TASK-3 in right human auricles. Immunocytochemistry experiments of human right auricular cardiomyocytes showed that TASK-3 is primarily localized at the plasma membrane. Single-channel recordings of right human auricles in the cell-attached mode, using divalent-cation-free solutions, revealed a TASK-1-like channel with a single-channel conductance of about 30pS. While homomeric TASK-3 channels were not found, we observed an intermediate single-channel conductance of about 55pS, possibly reflecting the heteromeric channel formed by TASK-1 and TASK-3. Subsequent experiments with TASK-1/TASK-3 tandem channels or with co-expressed TASK-1 and TASK-3 channels in HEK293 cells or Xenopus oocytes, supported that the 55pS channels observed in right auricles have electrophysiological characteristics of TASK-1/TASK-3 heteromers. In addition, co-expression experiments and single-channel recordings suggest that heteromeric TASK-1/TASK-3 channels have a predominant surface expression and a reduced affinity for TASK-1 blockers. In summary, the evidence for heteromeric TASK-1/TASK-3 channel complexes together with an altered pharmacologic response to TASK-1 blockers in vitro is likely to have further impact for studies isolating ITASK-1 from cardiomyocytes and for the development of drugs specifically targeting TASK-1 in atrial fibrillation treatment.

  11. Scalable Task Assignment for Heterogeneous Multi-Robot Teams

    Directory of Open Access Journals (Sweden)

    Paula García

    2013-02-01

    Full Text Available This work deals with the development of a dynamic task assignment strategy for heterogeneous multi‐robot teams in typical real world scenarios. The strategy must be efficiently scalable to support problems of increasing complexity with minimum designer intervention. To this end, we have selected a very simple auction‐based strategy, which has been implemented and analysed in a multi‐robot cleaning problem that requires strong coordination and dynamic complex subtask organization. We will show that the selection of a simple auction strategy provides a linear computational cost increase with the number of robots that make up the team and allows the solving of highly complex assignment problems in dynamic conditions by means of a hierarchical sub‐auction policy. To coordinate and control the team, a layered behaviour‐based architecture has been applied that allows the reusing of the auction‐based strategy to achieve different coordination levels.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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,…

  17. 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.

  18. How to Correct a Task Error: Task-Switch Effects Following Different Types of Error Correction

    Science.gov (United States)

    Steinhauser, Marco

    2010-01-01

    It has been proposed that switch costs in task switching reflect the strengthening of task-related associations and that strengthening is triggered by response execution. The present study tested the hypothesis that only task-related responses are able to trigger strengthening. Effects of task strengthening caused by error corrections were…

  19. 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.

  20. 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.

  1. Slushy weightings for the optimal pilot model. [considering visual tracking task

    Science.gov (United States)

    Dillow, J. D.; Picha, D. G.; Anderson, R. O.

    1975-01-01

    A pilot model is described which accounts for the effect of motion cues in a well defined visual tracking task. The effect of visual and motion cues are accounted for in the model in two ways. First, the observation matrix in the pilot model is structured to account for the visual and motion inputs presented to the pilot. Secondly, the weightings in the quadratic cost function associated with the pilot model are modified to account for the pilot's perception of the variables he considers important in the task. Analytic results obtained using the pilot model are compared to experimental results and in general good agreement is demonstrated. The analytic model yields small improvements in tracking performance with the addition of motion cues for easily controlled task dynamics and large improvements in tracking performance with the addition of motion cues for difficult task dynamics.

  2. 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.

  3. 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.

  4. 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.

  5. Assessing the Cost of Task Switching with a Three-Task Paradigm

    Science.gov (United States)

    Remington, Roger W.; Ruthruff, Eric; Johnston, James C.; Connors, Mary M. (Technical Monitor)

    1998-01-01

    To study task switching when subjects need not inhibit inappropriate responses, we examine tasks with non-overlapping stimulus sets (e.g. color patches and uncolored letters). A new three-task paradigm permits the dissociation of several otherwise confounded variables. We find that performance declines monotonically with increasing time since last performance of a task. Adjusting for the effects of this factor permits a fresh assessment of the relationship between task expectancy and recency (Ruthruff, Remington & Johnston, 1996).

  6. Visuospatial tasks affect locomotor control more than nonspatial tasks in older people.

    Directory of Open Access Journals (Sweden)

    Jasmine C Menant

    Full Text Available Previous research has shown that visuospatial processing requiring working memory is particularly important for balance control during standing and stepping, and that limited spatial encoding contributes to increased interference in postural control dual tasks. However, visuospatial involvement during locomotion has not been directly determined. This study examined the effects of a visuospatial cognitive task versus a nonspatial cognitive task on gait speed, smoothness and variability in older people, while controlling for task difficulty.Thirty-six people aged ≥75 years performed three walking trials along a 20 m walkway under the following conditions: (i an easy nonspatial task; (ii a difficult nonspatial task; (iii an easy visuospatial task; and (iv a difficult visuospatial task. Gait parameters were computed from a tri-axial accelerometer attached to the sacrum. The cognitive task response times and percentage of correct answers during walking and seated trials were also computed.No significant differences in either cognitive task type error rates or response times were evident in the seated conditions, indicating equivalent task difficulty. In the walking trials, participants responded faster to the visuospatial tasks than the nonspatial tasks but at the cost of making significantly more cognitive task errors. Participants also walked slower, took shorter steps, had greater step time variability and less smooth pelvis accelerations when concurrently performing the visuospatial tasks compared with the nonspatial tasks and when performing the difficult compared with the easy cognitive tasks.Compared with nonspatial cognitive tasks, visuospatial cognitive tasks led to a slower, more variable and less smooth gait pattern. These findings suggest that visuospatial processing might share common networks with locomotor control, further supporting the hypothesis that gait changes during dual task paradigms are not simply due to limited attentional

  7. Mission-Centered Network Models: Defending Mission-Critical Tasks From Deception

    Science.gov (United States)

    2015-09-29

    be dynamically changed in terms of what tasks should be reformulated or added in order to make the mission possible given the ongoing threat. • We...workflow specifications at the domain layer: 1. A language must be developed to express domain tasks with sufficient generality to encompass...provenance records. In addition, we use two extensions of these languages that are more specific to workflows and enable us to represent workflow

  8. 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.

  9. FEATURES OF USE INTERACTIVE TASKS IN MODERN MEANS OF COMPUTER-BASED TRAINING

    Directory of Open Access Journals (Sweden)

    Victoria V. Bova

    2014-01-01

    Full Text Available The article considers the problem of automated generation of interactive activities for learning software. This problem is relevant, since at the present stage of development of computer-based training systems can be traced need to build a tool that allows to implement various types of test and the training tasks on the basis of technologies of interactivity. We propose a tool to create dynamic tasks, enhance student’s interactivity with the system. 

  10. Task-specificity of balance training.

    Science.gov (United States)

    Giboin, Louis-Solal; Gruber, Markus; Kramer, Andreas

    2015-12-01

    Despite much research on balance training, it is still unclear whether balance training leads to highly task-specific adaptations or rather non-specific adaptations. Hence, in this study we examined whether balance training increased performance only in the balance task that was trained or also in non-trained tasks. Forty healthy participants (28 m 12 f, 25 ± 4 years, 177 ± 10 cm, 73 ± 14 kg) were assigned to one of two training groups (TGs) or a control group. Both TGs completed six sessions over 2 weeks, only the training device differed. Before and after the training, performance in the trained task as well as in additional untrained tasks was recorded. ANOVAs showed that each TG outperformed the other groups only in the task they had trained (e.g., task trained by TG1: +225% in TG1, only +41% and +30% in TG2 and control, group*time interaction, pbalance training resulted in highly task-specific effects, no transfer even to very similar tasks was observed. Therefore, we recommend identifying and training exactly those tasks that need improvement, and test the efficacy of training programs using specific tests instead of general tests with limited functional relevance.

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

    Science.gov (United States)

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

    1995-01-01

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

  12. Functional connectivity among spikes in low dimensional space during working memory task in rat.

    Directory of Open Access Journals (Sweden)

    Mei Ouyang

    Full Text Available Working memory (WM is critically important in cognitive tasks. The functional connectivity has been a powerful tool for understanding the mechanism underlying the information processing during WM tasks. The aim of this study is to investigate how to effectively characterize the dynamic variations of the functional connectivity in low dimensional space among the principal components (PCs which were extracted from the instantaneous firing rate series. Spikes were obtained from medial prefrontal cortex (mPFC of rats with implanted microelectrode array and then transformed into continuous series via instantaneous firing rate method. Granger causality method is proposed to study the functional connectivity. Then three scalar metrics were applied to identify the changes of the reduced dimensionality functional network during working memory tasks: functional connectivity (GC, global efficiency (E and casual density (CD. As a comparison, GC, E and CD were also calculated to describe the functional connectivity in the original space. The results showed that these network characteristics dynamically changed during the correct WM tasks. The measure values increased to maximum, and then decreased both in the original and in the reduced dimensionality. Besides, the feature values of the reduced dimensionality were significantly higher during the WM tasks than they were in the original space. These findings suggested that functional connectivity among the spikes varied dynamically during the WM tasks and could be described effectively in the low dimensional space.

  13. Functional connectivity among spikes in low dimensional space during working memory task in rat.

    Science.gov (United States)

    Ouyang, Mei; Li, Shuangyan; Tian, Xin

    2014-01-01

    Working memory (WM) is critically important in cognitive tasks. The functional connectivity has been a powerful tool for understanding the mechanism underlying the information processing during WM tasks. The aim of this study is to investigate how to effectively characterize the dynamic variations of the functional connectivity in low dimensional space among the principal components (PCs) which were extracted from the instantaneous firing rate series. Spikes were obtained from medial prefrontal cortex (mPFC) of rats with implanted microelectrode array and then transformed into continuous series via instantaneous firing rate method. Granger causality method is proposed to study the functional connectivity. Then three scalar metrics were applied to identify the changes of the reduced dimensionality functional network during working memory tasks: functional connectivity (GC), global efficiency (E) and casual density (CD). As a comparison, GC, E and CD were also calculated to describe the functional connectivity in the original space. The results showed that these network characteristics dynamically changed during the correct WM tasks. The measure values increased to maximum, and then decreased both in the original and in the reduced dimensionality. Besides, the feature values of the reduced dimensionality were significantly higher during the WM tasks than they were in the original space. These findings suggested that functional connectivity among the spikes varied dynamically during the WM tasks and could be described effectively in the low dimensional space.

  14. 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.

  15. Task-Scheduling in Cloud Computing using Credit Based Assignment Problem

    Directory of Open Access Journals (Sweden)

    Mousumi Paul

    2011-10-01

    Full Text Available This Cloud computing is a latest new computing paradigm where applications, data and IT services are provided across dynamic and geographically dispersed organization. Job scheduling systemproblem is a nucleus and demanding issue in Cloud Computing. How to utilize Cloud computing resources proficiently and gain the maximum profits with job scheduling system is one of the Cloud computing service providers’ ultimate objectives. In this paper we have used credit based scheduling decision to evaluate the entire group of task in the task queue and find the minimal completion time of alltask. Here cost matrix has been generated as the fair tendency of a task to be assigned in a resource.

  16. 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.

  17. 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

  18. Task Scheduling Based On Load Balancing Using Artificial Bee Colony In Cloud Computing Environment

    Directory of Open Access Journals (Sweden)

    Fatemeh Rastkhadiv

    2016-12-01

    Full Text Available Cloud computing is a development of distributed computing, parallel computing and grid computing. The aim of cloud computing is providing dynamic leasing of server capabilities as scalable, virtualized services to end users. Resource management as an important issue of cloud computing.Load balancing is a problem of resource management. Recently, Cloud schedulers based on bio-inspired and metaheuristic techniques have been proposed. A good task scheduler should adapt its scheduling strategy to the dynamic environment. Load balancing of nonpreemptive independent tasks on virtual machines is an important aspect of task scheduling in clouds.In this paper, wehave proposeda new cloud scheduler based on load balancing using by Artificial Bee Colonyalgorithm, one of the most popular bio-inspired technique. Artificial bee colony algorithm is an optimization metaheuristic algorithm based on a particular intelligent behavior of honey bee swarms. Our scheduler is designed to achieve well balanced load across virtual machines for maximizing the throughput and deliver to theminimum makespan. The experimental results simulatedusing Cloudsim shows its effectiveness to optimize load balancing and task scheduling compared with both of FCFS and ACO. Our proposed approach allows for more agile task handling while reducing task completion time. Our proposed approach reduces makespan and degree of imbalance.It distributes tasks and makes load balancing between virtual machines. Consequently the proposed algorithm increases performance and resource efficiency.

  19. Unnecessary work tasks and mental health

    DEFF Research Database (Denmark)

    Madsen, Ida E H; Tripathi, Manisha; Borritz, Marianne

    2014-01-01

    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...... decision latitude. CONCLUSIONS: Our findings suggest that the prevention of unnecessary work tasks may benefit employee mental health, particularly among employees with pre-existing mental health problems....... 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...

  20. 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.

  1. Task-focused modeling in automated agriculture

    Science.gov (United States)

    Vriesenga, Mark R.; Peleg, K.; Sklansky, Jack

    1993-01-01

    Machine vision systems analyze image data to carry out automation tasks. Our interest is in machine vision systems that rely on models to achieve their designed task. When the model is interrogated from an a priori menu of questions, the model need not be complete. Instead, the machine vision system can use a partial model that contains a large amount of information in regions of interest and less information elsewhere. We propose an adaptive modeling scheme for machine vision, called task-focused modeling, which constructs a model having just sufficient detail to carry out the specified task. The model is detailed in regions of interest to the task and is less detailed elsewhere. This focusing effect saves time and reduces the computational effort expended by the machine vision system. We illustrate task-focused modeling by an example involving real-time micropropagation of plants in automated agriculture.

  2. 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.

  3. Impaired attentional control in pedophiles in a sexual distractor task

    Directory of Open Access Journals (Sweden)

    Kirsten Jordan

    2016-12-01

    Full Text Available Pedophilic disorder, a subtype of paraphilia, is defined as a recurrent sexual interest in prepubescent children, which is characterized by persistent thoughts, fantasies, urges, sexual arousal or behavior. Besides a deviant sexual preference, sexual preoccupation was found to be a dynamic risk factor for reoffending. Thus, it is conceivable that sex offenders and especially sex offenders against children have difficulties to control their responses to sexual stimuli. In the current study pedophiles, forensic and non-forensic control subjects had to solve a cognitive task while sexual distractors were presented simultaneously. This kind of task also requires control functions. Therefore, data was analyzed with respect to attentional control while comparing eye movements towards sexual distractors and towards the cognitive task. We were mainly interested in how early (fixation latency and late (relative fixation time attentional processes were allocated to both, the cognitive target stimuli and the sexual distractors. Pedophiles demonstrated significantly lower attentional control in the sexual distractor task than both control groups (non-pedophiles. They showed a shorter fixation latency and longer fixation time for sexual distractors than non-pedophiles. Furthermore, pedophiles demonstrated a longer fixation latency and shorter fixation time for cognitive target stimuli. For classification analyses, an attention control index (ACI was built, i.e. the difference between eye movements on cognitive target stimuli and sexual distractors. For the ACI of early attentional processes, i.e. fixation latency, a good classification between pedophiles and non-pedophiles was found. We assumed that the measured attentional control represents inhibitory executive functions, specifically interference control. Further studies should examine if low attentional control in pedophiles is due to low motivation to solve the task or rather to a lack of ability to

  4. Impaired Attentional Control in Pedophiles in a Sexual Distractor Task.

    Science.gov (United States)

    Jordan, Kirsten; Fromberger, Peter; von Herder, Jakob; Steinkrauss, Henrike; Nemetschek, Rebekka; Witzel, Joachim; Müller, Jürgen L

    2016-01-01

    Pedophilic disorder, a subtype of paraphilia, is defined as a recurrent sexual interest in prepubescent children, which is characterized by persistent thoughts, fantasies, urges, sexual arousal, or behavior. Besides a deviant sexual preference, sexual preoccupation was found to be a dynamic risk factor for reoffending. Thus, it is conceivable that sex offenders and especially sex offenders against children have difficulties to control their responses to sexual stimuli. In the current study pedophiles, forensic and non-forensic control subjects had to solve a cognitive task, while sexual distractors were presented simultaneously. This kind of task also requires control functions. Therefore, data were analyzed with respect to attentional control while comparing eye movements toward sexual distractors and toward the cognitive task. We were mainly interested in how early (fixation latency) and late (relative fixation time) attentional processes were allocated to both, the cognitive target stimuli and the sexual distractors. Pedophiles demonstrated significantly lower attentional control in the sexual distractor task than both control groups (non-pedophiles). They showed a shorter fixation latency and longer fixation time for sexual distractors than non-pedophiles. Furthermore, pedophiles demonstrated a longer fixation latency and shorter fixation time for cognitive target stimuli. For classification analyses, an attentional control index (ACI) was built, i.e., the difference between eye movements on cognitive target stimuli and sexual distractors. For the ACI of early attentional processes, i.e., fixation latency, a good classification between pedophiles and non-pedophiles was found. We assumed that the measured attentional control represents inhibitory executive functions, specifically interference control. Further studies should examine if low attentional control in pedophiles is due to low motivation to solve the task or rather to a lack of ability to control

  5. Impaired Attentional Control in Pedophiles in a Sexual Distractor Task

    Science.gov (United States)

    Jordan, Kirsten; Fromberger, Peter; von Herder, Jakob; Steinkrauss, Henrike; Nemetschek, Rebekka; Witzel, Joachim; Müller, Jürgen L.

    2016-01-01

    Pedophilic disorder, a subtype of paraphilia, is defined as a recurrent sexual interest in prepubescent children, which is characterized by persistent thoughts, fantasies, urges, sexual arousal, or behavior. Besides a deviant sexual preference, sexual preoccupation was found to be a dynamic risk factor for reoffending. Thus, it is conceivable that sex offenders and especially sex offenders against children have difficulties to control their responses to sexual stimuli. In the current study pedophiles, forensic and non-forensic control subjects had to solve a cognitive task, while sexual distractors were presented simultaneously. This kind of task also requires control functions. Therefore, data were analyzed with respect to attentional control while comparing eye movements toward sexual distractors and toward the cognitive task. We were mainly interested in how early (fixation latency) and late (relative fixation time) attentional processes were allocated to both, the cognitive target stimuli and the sexual distractors. Pedophiles demonstrated significantly lower attentional control in the sexual distractor task than both control groups (non-pedophiles). They showed a shorter fixation latency and longer fixation time for sexual distractors than non-pedophiles. Furthermore, pedophiles demonstrated a longer fixation latency and shorter fixation time for cognitive target stimuli. For classification analyses, an attentional control index (ACI) was built, i.e., the difference between eye movements on cognitive target stimuli and sexual distractors. For the ACI of early attentional processes, i.e., fixation latency, a good classification between pedophiles and non-pedophiles was found. We assumed that the measured attentional control represents inhibitory executive functions, specifically interference control. Further studies should examine if low attentional control in pedophiles is due to low motivation to solve the task or rather to a lack of ability to control

  6. Intellectual productivity under task ambient lighting

    OpenAIRE

    2016-01-01

    A subjective experiment was conducted to evaluate intellectual productivity in three lighting conditions: (a) conventional ambient lighting, (b) task ambient lighting with normal colour temperature (5000 K), and (c) task ambient lighting with high colour temperature (6200 K). In the experiment, cognitive tasks were given to 24 participants. The concentration time ratio, which is a quantitative and objective evaluation index of the degree of concentration, was measured. The results showed that...

  7. Learning Multiple Tasks with Deep Relationship Networks

    OpenAIRE

    Long, Mingsheng; Wang, Jianmin

    2015-01-01

    Deep neural networks trained on large-scale dataset can learn transferable features that promote learning multiple tasks for inductive transfer and labeling mitigation. As deep features eventually transition from general to specific along the network, a fundamental problem is how to exploit the relationship structure across different tasks while accounting for the feature transferability in the task-specific layers. In this work, we propose a novel Deep Relationship Network (DRN) architecture...

  8. Task-oriented maximally entangled states

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Pankaj; Pradhan, B, E-mail: agrawal@iopb.res.i, E-mail: bpradhan@iopb.res.i [Institute of Physics, Sachivalaya Marg, Bhubaneswar, Orissa 751 005 (India)

    2010-06-11

    We introduce the notion of a task-oriented maximally entangled state (TMES). This notion depends on the task for which a quantum state is used as the resource. TMESs are the states that can be used to carry out the task maximally. This concept may be more useful than that of a general maximally entangled state in the case of a multipartite system. We illustrate this idea by giving an operational definition of maximally entangled states on the basis of communication tasks of teleportation and superdense coding. We also give examples and a procedure to obtain such TMESs for n-qubit systems.

  9. 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.

  10. Musing on the Use of Dynamic Software and Mathematics Epistemology

    Science.gov (United States)

    Santos-Trigo, Manuel; Reyes-Rodriguez, Aaron; Espinosa-Perez, Hugo

    2007-01-01

    Different computational tools may offer teachers and students distinct opportunities in representing, exploring and solving mathematical tasks. In this context, we illustrate that the use of dynamic software (Cabri Geometry) helped high school teachers to think of and represent a particular task dynamically. In this process, the teachers had the…

  11. Some Reflections on Task-Based Language Performance Assessment.

    Science.gov (United States)

    Bachman, Lyle F.

    2002-01-01

    Discusses problems in task-based language assessment, including the definition and sampling of tasks, generalizations across tasks, interpretations about broad ability and language use domains, and the notion of task difficulty. (Author/VWL)

  12. 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

  13. 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.

  14. 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.

  15. Exploiting Vector and Multicore Parallelsim for Recursive, Data- and Task-Parallel Programs

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Bin; Krishnamoorthy, Sriram; Agrawal, Kunal; Kulkarni, Milind

    2017-01-26

    Modern hardware contains parallel execution resources that are well-suited for data-parallelism-vector units-and task parallelism-multicores. However, most work on parallel scheduling focuses on one type of hardware or the other. In this work, we present a scheduling framework that allows for a unified treatment of task- and data-parallelism. Our key insight is an abstraction, task blocks, that uniformly handles data-parallel iterations and task-parallel tasks, allowing them to be scheduled on vector units or executed independently as multicores. Our framework allows us to define schedulers that can dynamically select between executing task- blocks on vector units or multicores. We show that these schedulers are asymptotically optimal, and deliver the maximum amount of parallelism available in computation trees. To evaluate our schedulers, we develop program transformations that can convert mixed data- and task-parallel pro- grams into task block-based programs. Using a prototype instantiation of our scheduling framework, we show that, on an 8-core system, we can simultaneously exploit vector and multicore parallelism to achieve 14×-108× speedup over sequential baselines.

  16. The shielding function of task rules in the context of task switching.

    Science.gov (United States)

    Reisenauer, Renate; Dreisbach, Gesine

    2014-02-01

    There is increasing evidence that task rules help shield the response against distractor interference. Here, the authors investigate the cognitive mechanisms underlying this assumed shielding function of task rules and how it is adjusted to changing task demands. In two experiments, participants switched between a noun categorization and an adjective categorization task. Target words were superimposed on distractor pictures. These pictures were always irrelevant and depicted either objects also used as target words in the noun task (noun distractors) or objects that were not part of the noun target-set but could be categorized according to the noun task (noun-related distractors). Results show that (a) on task repetitions shielding prevents interference from any distractors associated with a competing task; this is indicated by the lack of interference on adjective task repetitions; and (b) shielding is reduced on task switches. In the noun task, this reduction resulted in attenuated interference by noun-related distractors. In the adjective task, spatial distractors did not interfere despite the reduction. This result suggests that shielding is supported by a processing advantage for task-related information and not by distractor suppression.

  17. SOCIAL MEDIA MINING SHARED TASK WORKSHOP.

    Science.gov (United States)

    Sarker, Abeed; Nikfarjam, Azadeh; Gonzalez, Graciela

    2016-01-01

    Social media has evolved into a crucial resource for obtaining large volumes of real-time information. The promise of social media has been realized by the public health domain, and recent research has addressed some important challenges in that domain by utilizing social media data. Tasks such as monitoring flu trends, viral disease outbreaks, medication abuse, and adverse drug reactions are some examples of studies where data from social media have been exploited. The focus of this workshop is to explore solutions to three important natural language processing challenges for domain-specific social media text: (i) text classification, (ii) information extraction, and (iii) concept normalization. To explore different approaches to solving these problems on social media data, we designed a shared task which was open to participants globally. We designed three tasks using our in-house annotated Twitter data on adverse drug reactions. Task 1 involved automatic classification of adverse drug reaction assertive user posts; Task 2 focused on extracting specific adverse drug reaction mentions from user posts; and Task 3, which was slightly ill-defined due to the complex nature of the problem, involved normalizing user mentions of adverse drug reactions to standardized concept IDs. A total of 11 teams participated, and a total of 24 (18 for Task 1, and 6 for Task 2) system runs were submitted. Following the evaluation of the systems, and an assessment of their innovation/novelty, we accepted 7 descriptive manuscripts for publication--5 for Task 1 and 2 for Task 2. We provide descriptions of the tasks, data, and participating systems in this paper.

  18. 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

  19. Different neuroplasticity for task targets and distractors.

    Science.gov (United States)

    Spingath, Elsie Y; Kang, Hyun Sug; Plummer, Thane; Blake, David T

    2011-01-31

    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 nonselective

  20. 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

  1. Divided visual attention: A comparison of patients with multiple sclerosis and controls, assessed with an optokinetic nystagmus suppression task.

    Science.gov (United States)

    Williams, Isla M; Schofield, Peter; Khade, Neha; Abel, Larry A

    2016-12-01

    Multiple sclerosis (MS) frequently causes impairment of cognitive function. We compared patients with MS with controls on divided visual attention tasks. The MS patients' and controls' stare optokinetic nystagmus (OKN) was recorded in response to a 24°/s full field stimulus. Suppression of the OKN response, judged by the gain, was measured during tasks dividing visual attention between the fixation target and a second stimulus, central or peripheral, static or dynamic. All participants completed the Audio Recorded Cognitive Screen. MS patients had lower gain on the baseline stare OKN. OKN suppression in divided attention tasks was the same in MS patients as in controls but in both groups was better maintained in static than in dynamic tasks. In only dynamic tasks, older age was associated with less effective OKN suppression. MS patients had lower scores on a timed attention task and on memory. There was no significant correlation between attention or memory and eye movement parameters. Attention, a complex multifaceted construct, has different neural combinations for each task. Despite impairments on some measures of attention, MS patients completed the divided visual attention tasks normally.

  2. Control and Interference in Task Switching--A Review

    Science.gov (United States)

    Kiesel, Andrea; Steinhauser, Marco; Wendt, Mike; Falkenstein, Michael; Jost, Kerstin; Philipp, Andrea M.; Koch, Iring

    2010-01-01

    The task-switching paradigm offers enormous possibilities to study cognitive control as well as task interference. The current review provides an overview of recent research on both topics. First, we review different experimental approaches to task switching, such as comparing mixed-task blocks with single-task blocks, predictable task-switching…

  3. 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.

  4. 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

    and movements of the upper extremities among Danish house painters, and to establish sex-specific task exposure matrices. METHODS: To obtain task distributions, we sent out a questionnaire to all members of the Painters' Union in Denmark (N = 9364), of whom 53% responded. Respondents reported their task...... distributions in a typical week. To obtain task exposures, postures and movements were measured in 25 male and 25 female house painters for one whole working day per person. We used goniometers on the wrists, and inclinometers on the forehead and the upper arms. Participants filled in a logbook allowing task...... were found in task distribution and task exposures regarding postures and movements among Danish house painters. Sex-specific task exposure matrices were established....

  5. The Instructor as Manager: Time and Task.

    Science.gov (United States)

    Collis, Betty; Nijhuis, Gerard Gervedink

    2000-01-01

    Discusses the use of information and communication technologies at the University of Twente (Netherlands) and considers the management tasks, defined as all tasks outside of content-specific aspects, related to online learning via the World Wide Web that instructors must address. Focuses on handling assignments and feedback. (LRW)

  6. Antiphospholipid Syndrome Clinical Research Task Force Report

    NARCIS (Netherlands)

    Erkan, D.; Derksen, R.; Levy, R.; Machin, S.; Ortel, T.; Pierangeli, S.; Roubey, R.; Lockshin, M.

    2011-01-01

    The Antiphospholipid Syndrome (APS) Clinical Research Task Force (CRTF) was one of six Task Forces developed by the 13(th) International Congress on Antiphospholipid Antibodies (aPL) organization committee with the purpose of: a) evaluating the limitations of APS clinical research and developing gui

  7. 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.…

  8. 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)

  9. Instructional Objectives: Selecting and Devising Tasks

    Science.gov (United States)

    Mileff, Milo

    2013-01-01

    In the present paper and the discussion that follows, the author presents aspects of test construction and a careful description of instructional objectives. Constructing tests involves several stages such as describing language objectives, selecting appropriate test task, devising and assembling test tasks, and devising a scoring system for…

  10. 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...

  11. Designing Tasks for the Communicative Classroom.

    Science.gov (United States)

    Nunan, David

    This book provides teachers with a practical introduction to the design and development of communicative language learning tasks. The ideas presented are relevant to teachers working in or preparing for a range of situations with a variety of learner types. First, some basic issues concerning communicative learning tasks are discussed, and the…

  12. Metacognition in Monkeys during an Oculomotor Task

    Science.gov (United States)

    Middlebrooks, Paul G.; Sommer, Marc A.

    2011-01-01

    This study investigated whether rhesus monkeys show evidence of metacognition in a reduced, visual oculomotor task that is particularly suitable for use in fMRI and electrophysiology. The 2-stage task involved punctate visual stimulation and saccadic eye movement responses. In each trial, monkeys made a decision and then made a bet. To earn…

  13. 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.

  14. Multiagent task allocation in social networks

    NARCIS (Netherlands)

    De Weerdt, M.M.; Zhang, Y.; Klos, T.

    2011-01-01

    This paper proposes a new variant of the task allocation problem, where the agents are connected in a social network and tasks arrive at the agents distributed over the network. We show that the complexity of this problem remains NP-complete. Moreover, it is not approximable within some factor. In c

  15. Distributed Task Allocation in Social Networks

    NARCIS (Netherlands)

    De Weerdt, M.M.; Zhang, Y.; Klos, T.

    2007-01-01

    This paper proposes a new variant of the task allocation problem, where the agents are connected in a social network and tasks arrive at the agents distributed over the network. We show that the complexity of this problem remains NPhard. Moreover, it is not approximable within some factor. We develo

  16. Multiagent task allocation in social networks

    NARCIS (Netherlands)

    M.M. de Weerdt (Mathijs); Y. Zhang (Yingqian); T.B. Klos (Tomas)

    2011-01-01

    textabstractThis paper proposes a new variant of the task allocation problem, where the agents are connected in a social network and tasks arrive at the agents distributed over the network. We show that the complexity of this problem remains NP-complete. Moreover, it is not approximable within some

  17. First Workshop on Supporting Complex Search Tasks

    NARCIS (Netherlands)

    Gäde, M.; Hall, M.; Huurdeman, H.; Kamps, J.; Koolen, M.; Skov, M.; Toms, E.; Walsh, D.

    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 fragmente

  18. 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

  19. 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…

  20. 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…