The Experts below are selected from a list of 144 Experts worldwide ranked by ideXlab platform
Kenichi Sato - One of the best experts on this subject based on the ideXlab platform.
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self healing atm networks based on virtual path concept
IEEE Journal on Selected Areas in Communications, 1994Co-Authors: Ryutaro Kawamura, Kenichi Sato, I TokizawaAbstract:This paper proposes self-healing network techniques suitable for ATM networks in order to realize a high-reliablity B-ISDN. First, the characteristics of the virtual paths (VP) and their influence on failure restoration are discussed. A high-speed restoration technique which exploits the benefits of the VP is then proposed and described. The technique simplifies the message transmission processes and reduces the number of generated messages by using preassigned backup virtual paths. Next, the scheme used to design the backup VP routes and spare resource distribution for each link is proposed in order to create a network that applies the proposed restoration scheme. Next, self-reconstruction techniques of backup virtual paths are proposed for the realization of a reversionless restoration cycle. Finally, the feasibility of the distributed control operation is discussed. >
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dynamic bandwidth control of the virtual path in an asynchronous transfer mode network
IEEE Transactions on Communications, 1992Co-Authors: S Ohta, Kenichi SatoAbstract:The virtual path concept has several valuable features to construct an economical and efficient asynchronous transfer mode (ATM) network. One of them is bandwidth control which affords transmission efficiency improvement through statistical sharing of capacity. An effective bandwidth control algorithm and its calculated performance are described. Network performance with the algorithm is evaluated, and the bandwidth control is shown to successfully improve network transmission efficiency with only a slight increase in processing load compared to the fixed bandwidth scheme. A method is also proposed to equalize call loss probability for each virtual path. The effectiveness of the method is demonstrated by analysis. >
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self healing techniques utilizing virtual path concept for atm networks
Electronics and Communications in Japan Part I-communications, 1992Co-Authors: Ryutaro Kawamura, Hisaya Hadama, Kenichi SatoAbstract:Strong international effort has been made toward the realization of a B-ISDN based on ATM techniques. This paper proposes self-healing techniques for enhancing ATM network reliability. Self-healing is defined here as failed path restoration with distributed control mechanism by using cross-connects. First, the characteristics of virtual paths (VPs) are compared with those of digital paths in STM networks. It is clarified that VP benefits can be exploited for network restoration upon failure. Two high-speed self-healing algorithms that make the best use of VP characteristics are then proposed for restoring single-link failures. A technique for multiple-link failure restoration also is proposed. Finally, restoration performance is evaluated by computer simulation. It is confirmed that the proposed algorithm enables faster restoration than that possible using the existing algorithm for STM networks.
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a dynamically controllable atm transport network based on the virtual path concept
Broadband switching, 1991Co-Authors: S Ohta, Kenichi Sato, I TokizawaAbstract:Studies were carried out on an ATM (asynchronous transfer mode) transport network based on the virtual path concept. An arrangement of node functions in this network is proposed in which the call set-up process is excluded from transit nodes. This leads to a reduction in node processing and simplification of equipment by specialization of transit node functions. virtual path control is shown to bring benefits in efficiency and flexibility. Among them a transmission efficiency improvement due to bandwidth control, a simple three-value bandwidth control algorithm improves the efficiency considerably with only a slight processing increase. It is concluded that the virtual path concept can provide simple, economical, flexible, and high-performance networks. >
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virtual path and link capacity design for ATM networks
IEEE Journal on Selected Areas in Communications, 1991Co-Authors: Y. Sato, Kenichi SatoAbstract:A path and link capacity design method for asynchronous transfer mode (ATM) networks using statistical multiplexing of cells is proposed. By developing the design method, the statistical cell multiplexing effect can be exploited to significantly reduce required network resources. The necessary design procedures are identified. A simple and effective policing mechanism is proposed. An analytical method for the evaluation of cell multiplexing characteristics using declared parameters is provided. path and link capacity design algorithms that use these techniques are proposed. The effectiveness of the proposed design procedure is confirmed by comparing analytical results to those from a computer simulation. >
Marwan Krunz - One of the best experts on this subject based on the ideXlab platform.
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Load Profiling Based Routing for Guaranteed Bandwidth Flows
European Transactions on Telecommunications, 1999Co-Authors: Ibrahim Matta, Azer Bestavros, Marwan KrunzAbstract:To support the stringent Quality of Service (QoS) requirements of real-time (e.g. audio/video) applications in integrated services networks, several routing algorithms that allow for the reservation of the needed bandwidth over a virtual Circuit (VC), established on one of several candidate routes, have been proposed. Traditionally, such routing is done using the least-loaded concept, and thus results in balancing the load across the set of candidate routes. In this paper, we propose the use of load profiling as an attractive alternative to load balancing for routing guaranteed bandwidth VCs (flows). Load profiling techniques allow the distribution of “available” bandwidth across a set of candidate routes to match the characteristics of incoming VC QoS requests. We thoroughly characterize the performance of VC routing using load profiling and contrast it to routing using load balancing and load packing. We do so both analytically and via extensive simulations of multi-class traffic routing in virtual path (VP) based networks. Our findings show that for routing guaranteed bandwidth flows in VP networks, load profiling is desirable as it reduces VP bandwidth fragmentation, which increases the likelihood of accepting new VC requests. This fragmentation could be particularly harmful when the granularity of VC requests is large. Typically, this occurs when a common VC is established to carry the aggregate traffic flow of many high-bandwidth real-time sources. For VP-based networks, our simulation results show that our load-profiling VC routing scheme performs better or as well as the traditional load-balancing VC routing in terms of revenue under both skewed and uniform workloads. Furthermore, load-profiling routing improves routing fairness by proactively increasing the chances of admitting high-bandwidth Hows.
Ryutaro Kawamura - One of the best experts on this subject based on the ideXlab platform.
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self healing virtual path architecture in atm networks
IEEE Communications Magazine, 1995Co-Authors: Ryutaro Kawamura, I TokizawaAbstract:ATM network techniques have been actively researched and developed with the goal of realizing B-ISDN. ATM networks can transport signals of various services efficiently and economically, and offer the benefit of enhanced flexibility if the virtual path (VP) concept is adopted. Therefore, the ATM network will provide the infrastructure for B-ISDN. One of the most important themes in B-ISDN is the increased level of network reliability required to to match the high volume of data transmission that will be incurred by the information society and the "mission critical" nature of such data. The authors summarize self-healing network (SHN) schemes they have developed, and discuss problems that must be solved to realize SHN. >
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self healing atm networks based on virtual path concept
IEEE Journal on Selected Areas in Communications, 1994Co-Authors: Ryutaro Kawamura, Kenichi Sato, I TokizawaAbstract:This paper proposes self-healing network techniques suitable for ATM networks in order to realize a high-reliablity B-ISDN. First, the characteristics of the virtual paths (VP) and their influence on failure restoration are discussed. A high-speed restoration technique which exploits the benefits of the VP is then proposed and described. The technique simplifies the message transmission processes and reduces the number of generated messages by using preassigned backup virtual paths. Next, the scheme used to design the backup VP routes and spare resource distribution for each link is proposed in order to create a network that applies the proposed restoration scheme. Next, self-reconstruction techniques of backup virtual paths are proposed for the realization of a reversionless restoration cycle. Finally, the feasibility of the distributed control operation is discussed. >
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self healing techniques utilizing virtual path concept for atm networks
Electronics and Communications in Japan Part I-communications, 1992Co-Authors: Ryutaro Kawamura, Hisaya Hadama, Kenichi SatoAbstract:Strong international effort has been made toward the realization of a B-ISDN based on ATM techniques. This paper proposes self-healing techniques for enhancing ATM network reliability. Self-healing is defined here as failed path restoration with distributed control mechanism by using cross-connects. First, the characteristics of virtual paths (VPs) are compared with those of digital paths in STM networks. It is clarified that VP benefits can be exploited for network restoration upon failure. Two high-speed self-healing algorithms that make the best use of VP characteristics are then proposed for restoring single-link failures. A technique for multiple-link failure restoration also is proposed. Finally, restoration performance is evaluated by computer simulation. It is confirmed that the proposed algorithm enables faster restoration than that possible using the existing algorithm for STM networks.
S Ohta - One of the best experts on this subject based on the ideXlab platform.
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dynamic bandwidth control of the virtual path in an asynchronous transfer mode network
IEEE Transactions on Communications, 1992Co-Authors: S Ohta, Kenichi SatoAbstract:The virtual path concept has several valuable features to construct an economical and efficient asynchronous transfer mode (ATM) network. One of them is bandwidth control which affords transmission efficiency improvement through statistical sharing of capacity. An effective bandwidth control algorithm and its calculated performance are described. Network performance with the algorithm is evaluated, and the bandwidth control is shown to successfully improve network transmission efficiency with only a slight increase in processing load compared to the fixed bandwidth scheme. A method is also proposed to equalize call loss probability for each virtual path. The effectiveness of the method is demonstrated by analysis. >
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a dynamically controllable atm transport network based on the virtual path concept
Broadband switching, 1991Co-Authors: S Ohta, Kenichi Sato, I TokizawaAbstract:Studies were carried out on an ATM (asynchronous transfer mode) transport network based on the virtual path concept. An arrangement of node functions in this network is proposed in which the call set-up process is excluded from transit nodes. This leads to a reduction in node processing and simplification of equipment by specialization of transit node functions. virtual path control is shown to bring benefits in efficiency and flexibility. Among them a transmission efficiency improvement due to bandwidth control, a simple three-value bandwidth control algorithm improves the efficiency considerably with only a slight processing increase. It is concluded that the virtual path concept can provide simple, economical, flexible, and high-performance networks. >
Cagdas D. Onal - One of the best experts on this subject based on the ideXlab platform.
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A Soft Robotic Wearable Wrist Device for Kinesthetic Haptic Feedback
Frontiers Media S.A., 2018Co-Authors: Erik H. Skorina, Ming Luo, Cagdas D. OnalAbstract:Advances in soft robotics provide a unique approach for delivering haptic feedback to a user by a soft wearable device. Such devices can apply forces directly on the human joints, while still maintaining the safety and flexibility necessary for use in close proximity to the human body. To take advantage of these properties, we present a new haptic wrist device using pressure-driven soft actuators called reverse pneumatic artificial muscles (rPAMs) mounted on four sides of the wrist. These actuators are originally pre-strained and release compressive stress under pressure, applying a safe torque around the wrist joints while being compact and portable, representing the first soft haptic device capable of real-time feedback. To demonstrate the functional utility of this device, we created a virtual path-following task, wherein the user employs the motion of their wrist to control their embodied agent. We used the haptic wrist device to assist the user in following the path and study their performance with and without haptic feedback in multiple scenarios. Our results quantify the effect of wearable soft robotic haptic feedback on user performance. Specifically, we observed that our haptic feedback system improved the performance of users following complicated paths in a statistically significant manner, but did not show improvement for simple linear paths. Based on our findings, we anticipate broader applications of wearable soft robotic haptic devices toward intuitive user interactions with robots, computers, and other users
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Video_1_A Soft Robotic Wearable Wrist Device for Kinesthetic Haptic Feedback.MP4
2018Co-Authors: Erik H. Skorina, Ming Luo, Cagdas D. OnalAbstract:Advances in soft robotics provide a unique approach for delivering haptic feedback to a user by a soft wearable device. Such devices can apply forces directly on the human joints, while still maintaining the safety and flexibility necessary for use in close proximity to the human body. To take advantage of these properties, we present a new haptic wrist device using pressure-driven soft actuators called reverse pneumatic artificial muscles (rPAMs) mounted on four sides of the wrist. These actuators are originally pre-strained and release compressive stress under pressure, applying a safe torque around the wrist joints while being compact and portable, representing the first soft haptic device capable of real-time feedback. To demonstrate the functional utility of this device, we created a virtual path-following task, wherein the user employs the motion of their wrist to control their embodied agent. We used the haptic wrist device to assist the user in following the path and study their performance with and without haptic feedback in multiple scenarios. Our results quantify the effect of wearable soft robotic haptic feedback on user performance. Specifically, we observed that our haptic feedback system improved the performance of users following complicated paths in a statistically significant manner, but did not show improvement for simple linear paths. Based on our findings, we anticipate broader applications of wearable soft robotic haptic devices toward intuitive user interactions with robots, computers, and other users.
