The Experts below are selected from a list of 43452 Experts worldwide ranked by ideXlab platform
Stephen F Smith - One of the best experts on this subject based on the ideXlab platform.
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using bi Directional Information exchange to improve decentralized schedule driven traffic control
International Conference on Automated Planning and Scheduling, 2019Co-Authors: Stephen F SmithAbstract:Recent work in decentralized, schedule-driven traffic control has demonstrated the ability to improve the efficiency of traffic flow in complex urban road networks. In this approach, a scheduling agent is associated with each intersection. Each agent senses the traffic approaching its intersection and in real-time constructs a schedule that minimizes the cumulative wait time of vehicles approaching the intersection over the current look-ahead horizon. In order to achieve network level coordination in a scalable manner, scheduling agents communicate only with their direct neighbors. Each time an agent generates a new intersection schedule it communicates its expected outflows to its downstream neighbors as a prediction of future demand and these outflows are appended to the downstream agent’s locally perceived demand. In this paper, we extend this basic coordination algorithm to additionally incorporate the complementary flow of Information reflective of an intersection’s current congestion level to its upstream neighbors. We present an asynchronous decentralized algorithm for updating intersection schedules and congestion level estimates based on these bi-Directional Information flows. By relating this algorithm to the self-optimized decision making of the basic operation, we are able to approach network-wide optimality and reduce inefficiency due to strictly self-interested intersection control decisions.
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ICAPS - Using Bi-Directional Information Exchange to Improve Decentralized Schedule-Driven Traffic Control
2019Co-Authors: Stephen F SmithAbstract:Recent work in decentralized, schedule-driven traffic control has demonstrated the ability to improve the efficiency of traffic flow in complex urban road networks. In this approach, a scheduling agent is associated with each intersection. Each agent senses the traffic approaching its intersection and in real-time constructs a schedule that minimizes the cumulative wait time of vehicles approaching the intersection over the current look-ahead horizon. In order to achieve network level coordination in a scalable manner, scheduling agents communicate only with their direct neighbors. Each time an agent generates a new intersection schedule it communicates its expected outflows to its downstream neighbors as a prediction of future demand and these outflows are appended to the downstream agent’s locally perceived demand. In this paper, we extend this basic coordination algorithm to additionally incorporate the complementary flow of Information reflective of an intersection’s current congestion level to its upstream neighbors. We present an asynchronous decentralized algorithm for updating intersection schedules and congestion level estimates based on these bi-Directional Information flows. By relating this algorithm to the self-optimized decision making of the basic operation, we are able to approach network-wide optimality and reduce inefficiency due to strictly self-interested intersection control decisions.
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bi Directional Information exchange in decentralized schedule driven traffic control
Adaptive Agents and Multi-Agents Systems, 2018Co-Authors: Stephen F SmithAbstract:Recent work in decentralized, schedule-driven traffic control has demonstrated the ability to improve the efficiency of traffic flow in complex urban road networks. In this approach, each time an agent generates a new intersection schedule it communicates its expected outflows to its downstream neighbors as a prediction of future demand and these outflows are appended to the downstream agent's locally perceived demand. In this paper, we extend this basic coordination protocol to additionally incorporate the complementary flow of Information reflective of an intersection's current congestion level to its upstream neighbors. We present an asynchronous decentralized algorithm for updating intersection schedules and congestion level estimates based on these bi-Directional Information flows. By relating this algorithm to the self-optimized decision making of the basic protocol, we are able to approach network-wide optimality and reduce inefficiency due to myopic intersection control decisions.
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AAMAS - Bi-Directional Information Exchange in Decentralized Schedule-Driven Traffic Control
2018Co-Authors: Stephen F SmithAbstract:Recent work in decentralized, schedule-driven traffic control has demonstrated the ability to improve the efficiency of traffic flow in complex urban road networks. In this approach, each time an agent generates a new intersection schedule it communicates its expected outflows to its downstream neighbors as a prediction of future demand and these outflows are appended to the downstream agent's locally perceived demand. In this paper, we extend this basic coordination protocol to additionally incorporate the complementary flow of Information reflective of an intersection's current congestion level to its upstream neighbors. We present an asynchronous decentralized algorithm for updating intersection schedules and congestion level estimates based on these bi-Directional Information flows. By relating this algorithm to the self-optimized decision making of the basic protocol, we are able to approach network-wide optimality and reduce inefficiency due to myopic intersection control decisions.
Sungchul Kang - One of the best experts on this subject based on the ideXlab platform.
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Sensory saltation and phantom sensation for vibrotactile display of spatial and Directional Information
Presence: Teleoperators and Virtual Environments, 2012Co-Authors: Gi-hun Yang, Dongseok Ryu, Shinsuk Park, Sungchul KangAbstract:This study proposes a novel handheld vibrotactile display (T-hive) to provide a human operator with spatial and Directional Information. The proposed design is composed of a spherical knob with a vibrotactile surface and a moving base that allows 6-DOF motion. To isolate vibrotactile stimuli provided by multiple actuators, the spherical knob is divided into 13 vibrotactile modules. Each vibrotactile module consists of a vibration motor, a patch of spherical surface, and a vibration isolator. By coordinating the vibrotactile modules, the vibrotactile display delivers spatial and Directional Information based on phantom sensation and sensory saltation. Through experiments, we evaluated the effectiveness of the spatial and Directional Information perceived on the palm and fingers of the operator's hand. The experimental results confirm that vibrotactile feedback is useful for object control by providing intuitive Information.
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T-mobile: Vibrotactile display pad with spatial and Directional Information for hand-held device
2010 IEEE RSJ International Conference on Intelligent Robots and Systems, 2010Co-Authors: Gi-hun Yang, Sungchul KangAbstract:In this paper, we have applied phantom sensation and sensory saltation to generate spatial and Directional Information using a vibrotactile display pad providing vibrotactile cues, T-mobile. A grooved and slim design is applied to the contact side of the T-mobile for comfortable gripping, and the contact part consists of 12 vibrotactile panels which can operate independently and separately. To maintain isolation among vibrotactile actuators, the surface of the cover is divided into several pieces. Each vibrating module consists of a linear resonant vibrational motor, a section of covering surface, and a vibration isolator. As an evaluation of the developed device, two experiments were conducted to test whether Directional Information and spatial Information can be successfully displayed by the device. As a result, spatial and Directional Information is useful for displaying intuitive Information for hand-held navigation with vibrotactile feedback.
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IROS - T-mobile: Vibrotactile display pad with spatial and Directional Information for hand-held device
2010 IEEE RSJ International Conference on Intelligent Robots and Systems, 2010Co-Authors: Gi-hun Yang, Moon-sub Jin, Yeonsub Jin, Sungchul KangAbstract:In this paper, we have applied phantom sensation and sensory saltation to generate spatial and Directional Information using a vibrotactile display pad providing vibrotactile cues, T-mobile. A grooved and slim design is applied to the contact side of the T-mobile for comfortable gripping, and the contact part consists of 12 vibrotactile panels which can operate independently and separately. To maintain isolation among vibrotactile actuators, the surface of the cover is divided into several pieces. Each vibrating module consists of a linear resonant vibrational motor, a section of covering surface, and a vibration isolator. As an evaluation of the developed device, two experiments were conducted to test whether Directional Information and spatial Information can be successfully displayed by the device. As a result, spatial and Directional Information is useful for displaying intuitive Information for hand-held navigation with vibrotactile feedback.
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Vibrotactile display for hand-held input device providing spatial and Directional Information
World Haptics 2009 - Third Joint EuroHaptics conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, 2009Co-Authors: Gi-hun Yang, Sungchul KangAbstract:A hand-held input device providing vibrotactile cues is developed for transmitting spatial and Directional Information to the users controlling a mobile robot or a manipulator arm. A sphere-shaped handle is applied to make comfortable for gripping the handle, and the input device can provide six degrees of freedom motion of the handle. For maintaining isolation among vibrotactile actuators, surface of the sphere is divided into several pieces. Each vibrating module consists of a vibration motor, a piece of sphere surface and a vibration absorber. Spatial and Directional Information can be generated using sensory saltation and phantom sensation. As an evaluation of the developed device, two experiments were conducted. Experimental results show that the developed device is useful for displaying intuitive Information for controlling mobile robot with vibrotactile feedback.
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WHC - Vibrotactile display for hand-held input device providing spatial and Directional Information
World Haptics 2009 - Third Joint EuroHaptics conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, 2009Co-Authors: Gi-hun Yang, Dongseok Ryu, Sungchul KangAbstract:A hand-held input device providing vibrotactile cues is developed for transmitting spatial and Directional Information to the users controlling a mobile robot or a manipulator arm. A sphere-shaped handle is applied to make comfortable for gripping the handle, and the input device can provide six degrees of freedom motion of the handle. For maintaining isolation among vibrotactile actuators, surface of the sphere is divided into several pieces. Each vibrating module consists of a vibration motor, a piece of sphere surface and a vibration absorber. Spatial and Directional Information can be generated using sensory saltation and phantom sensation. As an evaluation of the developed device, two experiments were conducted. Experimental results show that the developed device is useful for displaying intuitive Information for controlling mobile robot with vibrotactile feedback.
Keiichi Kitajo - One of the best experts on this subject based on the ideXlab platform.
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Information-theoretic approach to detect Directional Information flow in EEG signals induced by TMS.
Neuroscience research, 2019Co-Authors: Keiichi Kitajo, Katsunori KitanoAbstract:Abstract Effective connectivity analysis has been widely applied to noninvasive recordings such as functional magnetic resonance imaging and electroencephalograms (EEGs). Previous studies have aimed to extract the causal relations between brain regions, but the validity of the derived connectivity has not yet been fully determined. This is because it is generally difficult to identify causality in the usual experimental framework based on observations alone. Transcranial magnetic stimulation (TMS) provides a framework in which a controllable perturbation is applied to a local brain region and the effect is examined by comparing the neural activity with and without this stimulation. This study evaluates two methods for effective connectivity analysis, symbolic transfer entropy (STE) and vector autoregression (VAR), by applying them to TMS-EEG data. In terms of the consistency of results from different experimental sessions, STE is found to yield robust results irrespective of sessions, whereas VAR produces less correlation between sessions. Furthermore, STE preferentially detects the Directional Information flow from the TMS target. Taken together, our results suggest that STE is a reliable method for detecting the effect of TMS, implying that it would also be useful for identifying neural activity during cognitive tasks and resting states.
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Transcranial magnetic stimulation-induced global propagation of transient phase resetting associated with Directional Information flow
Frontiers in human neuroscience, 2014Co-Authors: Masahiro Kawasaki, Yutaka Uno, Jumpei Mori, Kenji Kobata, Keiichi KitajoAbstract:Electroencephalogram (EEG) phase synchronization analyses can reveal large-scale communication between distant brain areas. However, it is not possible to identify the Directional Information flow between distant areas using conventional phase synchronization analyses. In the present study, we applied transcranial magnetic stimulation (TMS) to the occipital area in subjects who were resting with their eyes closed, and analyzed the spatial propagation of transient TMS-induced phase resetting by using the transfer entropy (TE), to quantify the causal and Directional flow of Information. The time-frequency EEG analysis indicated that the theta (5 Hz) phase locking factor (PLF) reached its highest value at the distant area (the motor area in this study), with a time lag that followed the peak of the transient PLF enhancements of the TMS-targeted area at the TMS onset. Phase-preservation index (PPI) analyses demonstrated significant phase resetting at the TMS-targeted area and distant area. Moreover, the TE from the TMS-targeted area to the distant area increased clearly during the delay that followed TMS onset. Interestingly, the time lags were almost coincident between the PLF and TE results (152 vs. 165 ms), which provides strong evidence that the emergence of the delayed PLF reflects the causal Information flow. Such tendencies were observed only in the higher-intensity TMS condition, and not in the lower-intensity or sham TMS conditions. Thus, TMS may manipulate large-scale causal relationships between brain areas in an intensity-dependent manner. We demonstrated that single-pulse TMS modulated global phase dynamics and Directional Information flow among synchronized brain networks. Therefore, our results suggest that single-pulse TMS can manipulate both incoming and outgoing Information in the TMS-targeted area associated with functional changes.
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P 134. Causal and Directional Information flow from visual to motor areas during resting-state revealed by a TMS-EEG co-registration
Clinical Neurophysiology, 2013Co-Authors: Masahiro Kawasaki, Yuji Mizuno, Keiichi KitajoAbstract:Our brain is spontaneously active and constructs a resting-state network even when there are no sensory inputs or no motor output responses. Such networks connect many distributed brain regions, however but it is not well known how clear about causal and Directional Information flow occurs within the resting-state network. Such causal Information flow could be evaluated by perturbing electroencephalograph (EEG) oscillations using transcranial magnetic stimulation (TMS). A single-pulse TMS can reset the phase of ongoing cortical oscillations. Here we analyzed global propagation of phase resetting across different brain regions to elucidate causal Information flow. More specifically, we applied single-pulse TMS to the resting-state brain and analyzed spatial spread of TMS-induced phase resetting in the human brain. Eleven right-handed subjects took part in this experiment. A single-pulse TMS was delivered to left primary motor cortex or visual cortex at 2.5–3.5 s intervals during the eye-closed resting states. Each subject completed four separate sessions; two TMS intensities (95% and 50%; 100% means motor threshold) × two TMS-target locations (left primary motor cortex (C3) and visual cortex (Oz)). Each session consisted of 50 times of TMS applications. To confirm their arousal, they were asked to response by their right index finger when they felt sensed a weak flashlight which was sometimes induced by a white flash square on a computer display during inter-pulse interval periods. EEGs were measured from 67 scalp electrodes. To elucidate the cortical activity free without errors from volume conduction, we applied current source density analysis. Next, we removed the EEG epochs that would be affected by TMS artifacts, using a linear interpolation. Finally, to identify the time–frequency (TF) phases, we applied wavelet transforms using Morlet’s wavelets. TMS-induced evoked phase resetting was assessed calculated by phase locking values (PLV) at each electrode, time point and frequency. The time–frequency EEG results showed enhanced PLV for of both the low and high frequency bands at the TMS target electrodes at the instant of TMS applications. In particular, the theta (4–8 Hz) PLV increased from the onset of TMS applications around the TMS target locations. Under visual area-targeting TMS, phase resetting (i.e. enhanced PLV) of the theta oscillations were transmitted from the visual areas to the motor areas (in particular to the left motor area). Under high largeTMS intensity, the left motor electrode showed the highest theta PLV from about 150 ms after the onset of TMS applications, whereas PLV at the visual electrode reached peaking values just when TMS was applied. Under low small TMS intensity, such regional transmissions of the phase resets decreased and disappeared. In contrast, the TMS to the left motor areas increased only the theta PLV in the left and central motor areas. High PLV was observed from about 100 ms after TMS applications. In contrast, the visual areas showed low small PLV. Similar to the visual area-targeting TMS, the regional transitions of the theta PLV disappeared when the TMS intensity was low small. We succeeded in evaluating Directional Information flow in the resting state. Our results indicated the existence of potential networks from the sensory input regions to the motor output regions in the resting state. The sensory–motor mechanisms might be related to a spontaneous preparation of perception–action coupling; e.g. seeing a visual stimulus, making a decision, and then responding by the motor output.
Gi-hun Yang - One of the best experts on this subject based on the ideXlab platform.
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Sensory saltation and phantom sensation for vibrotactile display of spatial and Directional Information
Presence: Teleoperators and Virtual Environments, 2012Co-Authors: Gi-hun Yang, Dongseok Ryu, Shinsuk Park, Sungchul KangAbstract:This study proposes a novel handheld vibrotactile display (T-hive) to provide a human operator with spatial and Directional Information. The proposed design is composed of a spherical knob with a vibrotactile surface and a moving base that allows 6-DOF motion. To isolate vibrotactile stimuli provided by multiple actuators, the spherical knob is divided into 13 vibrotactile modules. Each vibrotactile module consists of a vibration motor, a patch of spherical surface, and a vibration isolator. By coordinating the vibrotactile modules, the vibrotactile display delivers spatial and Directional Information based on phantom sensation and sensory saltation. Through experiments, we evaluated the effectiveness of the spatial and Directional Information perceived on the palm and fingers of the operator's hand. The experimental results confirm that vibrotactile feedback is useful for object control by providing intuitive Information.
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T-mobile: Vibrotactile display pad with spatial and Directional Information for hand-held device
2010 IEEE RSJ International Conference on Intelligent Robots and Systems, 2010Co-Authors: Gi-hun Yang, Sungchul KangAbstract:In this paper, we have applied phantom sensation and sensory saltation to generate spatial and Directional Information using a vibrotactile display pad providing vibrotactile cues, T-mobile. A grooved and slim design is applied to the contact side of the T-mobile for comfortable gripping, and the contact part consists of 12 vibrotactile panels which can operate independently and separately. To maintain isolation among vibrotactile actuators, the surface of the cover is divided into several pieces. Each vibrating module consists of a linear resonant vibrational motor, a section of covering surface, and a vibration isolator. As an evaluation of the developed device, two experiments were conducted to test whether Directional Information and spatial Information can be successfully displayed by the device. As a result, spatial and Directional Information is useful for displaying intuitive Information for hand-held navigation with vibrotactile feedback.
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IROS - T-mobile: Vibrotactile display pad with spatial and Directional Information for hand-held device
2010 IEEE RSJ International Conference on Intelligent Robots and Systems, 2010Co-Authors: Gi-hun Yang, Moon-sub Jin, Yeonsub Jin, Sungchul KangAbstract:In this paper, we have applied phantom sensation and sensory saltation to generate spatial and Directional Information using a vibrotactile display pad providing vibrotactile cues, T-mobile. A grooved and slim design is applied to the contact side of the T-mobile for comfortable gripping, and the contact part consists of 12 vibrotactile panels which can operate independently and separately. To maintain isolation among vibrotactile actuators, the surface of the cover is divided into several pieces. Each vibrating module consists of a linear resonant vibrational motor, a section of covering surface, and a vibration isolator. As an evaluation of the developed device, two experiments were conducted to test whether Directional Information and spatial Information can be successfully displayed by the device. As a result, spatial and Directional Information is useful for displaying intuitive Information for hand-held navigation with vibrotactile feedback.
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Vibrotactile display for hand-held input device providing spatial and Directional Information
World Haptics 2009 - Third Joint EuroHaptics conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, 2009Co-Authors: Gi-hun Yang, Sungchul KangAbstract:A hand-held input device providing vibrotactile cues is developed for transmitting spatial and Directional Information to the users controlling a mobile robot or a manipulator arm. A sphere-shaped handle is applied to make comfortable for gripping the handle, and the input device can provide six degrees of freedom motion of the handle. For maintaining isolation among vibrotactile actuators, surface of the sphere is divided into several pieces. Each vibrating module consists of a vibration motor, a piece of sphere surface and a vibration absorber. Spatial and Directional Information can be generated using sensory saltation and phantom sensation. As an evaluation of the developed device, two experiments were conducted. Experimental results show that the developed device is useful for displaying intuitive Information for controlling mobile robot with vibrotactile feedback.
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WHC - Vibrotactile display for hand-held input device providing spatial and Directional Information
World Haptics 2009 - Third Joint EuroHaptics conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems, 2009Co-Authors: Gi-hun Yang, Dongseok Ryu, Sungchul KangAbstract:A hand-held input device providing vibrotactile cues is developed for transmitting spatial and Directional Information to the users controlling a mobile robot or a manipulator arm. A sphere-shaped handle is applied to make comfortable for gripping the handle, and the input device can provide six degrees of freedom motion of the handle. For maintaining isolation among vibrotactile actuators, surface of the sphere is divided into several pieces. Each vibrating module consists of a vibration motor, a piece of sphere surface and a vibration absorber. Spatial and Directional Information can be generated using sensory saltation and phantom sensation. As an evaluation of the developed device, two experiments were conducted. Experimental results show that the developed device is useful for displaying intuitive Information for controlling mobile robot with vibrotactile feedback.
Thomas D. Seeley - One of the best experts on this subject based on the ideXlab platform.
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Do honeybees use the Directional Information in round dances to find nearby food sources
Animal Behaviour, 2012Co-Authors: Sean R. Griffin, Michael L. Smith, Thomas D. SeeleyAbstract:Throughout his writings about how honeybees communicate with dances, Karl von Frisch described two types of recruitment dance: the round dance, which supposedly indicates the presence of a food source somewhere near the hive, and the waggle dance, which indicates the distance and direction of a food source more than 100 m from the hive. The view that round dances and waggle dances are distinct recruitment signals has been revised in light of the finding that distance and direction Information are encoded (albeit imprecisely) in round dances. It has remained unclear, however, whether dance followers can use the location Information in round dances. In the present study, we looked at recruitment to nearby food sources and found that dance followers can use the Directional Information in the dances advertising these food sources. Directional bias in recruitment was found for food sources as close as 5 m from the hive. Controls for effects of assembly pheromone and bee presence at the advertised food sources indicate that these factors play a minimal role, relative to dance Information, in producing the Directional recruitment. Our results provide further support for the view that round dances are best viewed as waggle dances indicating nearby food sources, not as a separate type of dance.