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Research Interests: Computer Science, Mobile Ad Hoc Networks, Wireless Mesh Networks, Routing protocols, Probability, and 11 moreProbabilistic Logic, Mobile Ad Hoc Network, Computer Network, Ad Hoc Networks, Multicast, Ad hoc network, Network Topology, Wireless Application Protocol, Network Simulator, Wireless Ad Hoc Network, and Intelligent Networks
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Research Interests: Computer Science, Biomedical Engineering, Service Quality, Scheduling, Algorithm, and 14 moreBroadband, Computer Network, Wireless Network, QoS, Quality of Service, Wireless, Information Infrastructure, Wireless Broadband, Telecommunication network, Wireline, Wireless Communication, Electrical And Electronic Engineering, Scheduling Algorithm, and Wireless Data
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Research Interests: Computer Science, Distributed Computing, Routing, Packet scheduling, Communication Networks, and 14 moreComputer Network, Performance Model, Communications networks, Delays, Scheduling Algorithms, High speed networks, Community Networks, Multipath Routing, Cost Function, Convex functions, Traffic Congestion, Generalized Gaussian Distribution, Disjoint Paths, and Schedules
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Research Interests: Computer Science, Optics, Medical Imaging, Fiber Optics, Photonics, and 15 morePacket Switching, Optical Switch, Fabrics, Computer Network, Optical, Light, Optical Packet Switching, Optical physics, Delay, Optical fiber, Control Reconfiguration, Blocking Probability, Optical Fibers, Optical Switches, and Electrical And Electronic Engineering
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Research Interests: Computer Science, Distributed Computing, Signal Processing, Multimedia, Communication System, and 15 moreComputer Network, Quality of Service, Information Exchange, ATM networks, Low Power, ATM, Network Architecture, High Speed, Multimedia Traffic, Multiple Access, Office Building, Electrical And Electronic Engineering, Control Architecture, Multipath Propagation, and Multiple Access Channel
Research Interests: Computer Science, Distributed Computing, Computer Network, Multicast, Routing Protocol, and 9 moreMPEG enabled Multicast Routing, Boolean Satisfiability, Multipath Routing, Electrical And Electronic Engineering, Scheduling Algorithm, Unicast, Shortest Path Routing, Disjoint Paths, and MULTICAST routing
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Research Interests: Engineering, Electrical Engineering, Computer Science, Distributed Computing, Routing, and 15 moreThe Internet, Business Communication, Satellite Communication, Quality of Service, Internet Architecture, Internet Access, Satellite, IEEE Communications Magazine, Multiple Access, Internet, Electrical And Electronic Engineering, Satellite Network, Heterogeneous Network, Multiple access control, and Application Software
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The ALOHA and Carrier Sense Multiple Access (CSMA) protocols have been proposed for packet radio networks (PRN). However, CSMA/CD which gives superior performance and has been successful applied in local area networks cannot be readily... more
The ALOHA and Carrier Sense Multiple Access (CSMA) protocols have been proposed for packet radio networks (PRN). However, CSMA/CD which gives superior performance and has been successful applied in local area networks cannot be readily applied in PRN since the locally generated signals will overwhelm a remote transmission, rendering it impossible to tell whether a collision has occurred or not. In addition, CSMA and CSMA/CD suffer from the “hidden node” problem in a multihop PRN. In this paper, we develop the Receiver-Initiated Busy-Tone Multiple Access Protocol to resolve these difficulties. Both fully connected and multihop networks are studied. The busy tone serves as an acknowledgement and prevents conflicting transmissions from other nodes, including “hidden nodes”.
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Research Interests: Engineering, Computer Science, Technology, Voice over IP, Computer Network, and 14 moreIEEE, wireless local area network (WLAN), Wlan, Wireless Lan, Capacity, Rich Internet Application, Quality of Service (QoS), Medium Access Control, Voice Over Internet Protocol, Voice Over Internet Protocol (VoIP), Access Point, Transmission Control Protocol, MAC Protocol, and Wireless Local Area Network
Vehicular ad hoc network (VANET) is an emerging type of networks which facilitates vehicles on roads to communicate for driving safety. The basic idea is to allow arbitrary vehicles to broadcast ad hoc messages (e.g. traffic accidents) to... more
Vehicular ad hoc network (VANET) is an emerging type of networks which facilitates vehicles on roads to communicate for driving safety. The basic idea is to allow arbitrary vehicles to broadcast ad hoc messages (e.g. traffic accidents) to other vehicles. However, this raises the concern of security and privacy. Messages should be signed and verified before they are trusted while
Research Interests: Computer Science, Distributed Computing, Computer Security, Group communication, Security and Privacy, and 15 moreAuthentication, Computer Network, Ad Hoc Networks, Security Analysis, Sensor Network, Bloom Filter, Vehicular ad hoc network, Success Rate, Secure Communication, Simulation Study, Boolean Satisfiability, Traffic Accident, Electrical And Electronic Engineering, Group Communications, and Binary Search
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ABSTRACT An interactive video-on-demand (IVOD) system requires continuous video playback, and network bandwidth should be allocated to satisfy quality of service (QOS) requirements. Bandwidth allocation methods can be classified into two... more
ABSTRACT An interactive video-on-demand (IVOD) system requires continuous video playback, and network bandwidth should be allocated to satisfy quality of service (QOS) requirements. Bandwidth allocation methods can be classified into two categories: static and dynamic. There are two types of static allocation methods: deterministic and statistical. In deterministic allocation, bandwidth which provides deterministic QOS is allocated only at call setup time. Although the implementation is simpler than other methods, it suffers from low bandwidth utilization. In this paper, we propose a new deterministic static bandwidth allocation method which improves bandwidth utilization. This method does not require set-top box (STB) control. This decreases the STB cost and the signalling overhead in the network
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The authors consider a static routing problem in a network with failure-prone links. Two copies of each externally generated message are sent from the source to the destination along two disjoint paths with the objective of reducing the... more
The authors consider a static routing problem in a network with failure-prone links. Two copies of each externally generated message are sent from the source to the destination along two disjoint paths with the objective of reducing the delay resulting from retransmissions of unsuccessful packets. They formulate an optimal-routing problem using a suitable delay function. This results in a nonlinear programming problem of minimizing the delay over routing assignment under certain constraints. Specifically, they impose a disjoint-path constraint on the route assignment. This nonlinear program is solved by an iteration method incorporating a combinatorial algorithm. The solution converges to the global minimum for a convex objective function over a convex feasible region
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A new approach for analyzing the performance of communication networks with unreliable components was given in a recent paper [2]. An algorithm was developed to generate the most probable states of a network, and an analysis of those... more
A new approach for analyzing the performance of communication networks with unreliable components was given in a recent paper [2]. An algorithm was developed to generate the most probable states of a network, and an analysis of those states gave a good approximation of the network performance. In this paper, we present a new algorithm for generating the most probable
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... Other reductions include delta-star and star-delta transformation, bridge reduction, polygon-to-chain reduction, and 2-connected digraph reductions. More discussions and examples on reduction techniques and algorithms can be foundin... more
... Other reductions include delta-star and star-delta transformation, bridge reduction, polygon-to-chain reduction, and 2-connected digraph reductions. More discussions and examples on reduction techniques and algorithms can be foundin [35-45]. ...
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The effect of sending redundant copies of each message in a point-to-point communication network with unreliable components is studied. To increase the probability of success, it is desirable to send the copies along link-disjoint or... more
The effect of sending redundant copies of each message in a point-to-point communication network with unreliable components is studied. To increase the probability of success, it is desirable to send the copies along link-disjoint or vertex-disjoint paths. The mean network delay is used as the basis of comparison of a two-copy scheme with a single-copy scheme. The effects of network routing and retransmission due to failures are analyzed. The environment in which the two-copy scheme achieves smaller network delay is discussed. The loop-freedom property of memoryless routing is briefly discussed. For the optimal two-copy scheme which minimizes the mean network delay, one solution that does not satisfy the constaint of sending along vertex-disjoint paths is found. Some heuristics to find two-copy routing schemes that satisfy this constraint are proposed.link_to_subscribed_fulltex
Research Interests: Computer Science and ICC
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This paper analyzes the throughput of an adaptive hybrid ARQ communications protocol used with a continuous-time two-state Markovian channel. The proposed protocol adapts to changes in the channel state. i.e., changes in noise level, by... more
This paper analyzes the throughput of an adaptive hybrid ARQ communications protocol used with a continuous-time two-state Markovian channel. The proposed protocol adapts to changes in the channel state. i.e., changes in noise level, by selecting one of two block error-correction codes for each packet according to an estimate of the next channel state; the estimate, based on the error pattern in the previous packet, is fed back to the transmitter via the acknowledgment. We compare throughputs and computational costs of three next-state estimators. The first, an optimal estimator, is shown to be impractical. A second, suboptimal, estimator is found to require negligible computation and memory. An improved suboptimal estimator is also considered. Throughputs are evaluated; numerical results are presented. The throughput improvement due to adaptation is shown to be greater for the continuous-time channel than for the discrete-time channel with sirmilar parameters. The improvemient is also less sensitive to the parameters.
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An interactive video-on-demand (IVOD) system requires transmission bandwidth allocation for each user. Since the volume of data in each video frame is variable, dynamic bandwidth allocation is desirable. In this paper, a new scheme that... more
An interactive video-on-demand (IVOD) system requires transmission bandwidth allocation for each user. Since the volume of data in each video frame is variable, dynamic bandwidth allocation is desirable. In this paper, a new scheme that dynamically determines required bandwidth based on the queue length at the viewer's set-top box (STB) is proposed. Although this method is in the renegotiated CBR (constant bit rate) category, it requires no precalculation, so it is easily applied to IVOD. The variance of the video transmission rate for each user is an important factor as it affects the service quality of other multiplexed traffic. It is desirable that the transmission rate is changed gradually. A multi-layer concept is introduced to achieve this. Through numerical evaluation using actual movie data, we demonstrate that the variance of the transmission rate is close to the optimal value and the bandwidth utilization is close to unity.
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Transmission of variable-bit-rate (VBR) video over packet- switched networks is a very challenging problem, and has received much attention in the research community. The burstiness of VBR video makes it very hard to design efficient... more
Transmission of variable-bit-rate (VBR) video over packet- switched networks is a very challenging problem, and has received much attention in the research community. The burstiness of VBR video makes it very hard to design efficient transmission schemes that will achieve a high level of network utilization. Promising work has been done recently for the transmission of stored video, based on the idea of video prefetching. These protocols use a buffer located at the client's set-top box (STB) to store future frames that are sent when the transmission link is underutilized. Experi- mental results have shown that video prefetching can achieve a utilization of almost 100% without any need for buffering inside the network. How- ever, no admission control algorithm has been proposed for these protocols to enable their deployment. In this paper, we use the theory of effective bandwidths to develop an admission control algorithm. Each user is al- lowed to interact with the system, and ...
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A distributed database (DDB) consists of copies of data files (usually redundant) geographically distributed and managed on a computer network. One important problem in DDB research is that of concurrency control. This paper develops a... more
A distributed database (DDB) consists of copies of data files (usually redundant) geographically distributed and managed on a computer network. One important problem in DDB research is that of concurrency control. This paper develops a performance model of timestamp-ordering concurrency control algorithms in a DDB. The performance model consists of five components: input data collection, transaction processing model, communication subnetwork model, conflict model, and performance measures estimation. In this paper we describe the conflict model in detail. We first determine the probability of transaction restarts, the probability of transaction blocking, and the delay due to blocking for the basic timestamp-ordering algorithm. We then develop conflict models for variations of the basic algorithm. These conflict models are illustrated by numerical examples.
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... IEEE Log Number 8406427. ... In Section IV, we define the interference factor. ... NETWORK MODEL The nodes (or terminals) of the network are distributed as a two-dimensional Poisson point process with density X, ie, Pr (finding i... more
... IEEE Log Number 8406427. ... In Section IV, we define the interference factor. ... NETWORK MODEL The nodes (or terminals) of the network are distributed as a two-dimensional Poisson point process with density X, ie, Pr (finding i nodes in an area of size A ) = (XA)' exp (- xA)/i!, i = 0 ...
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This paper presents a new model to study the reliability of communication networks in which link failures are statistically dependent. The approach tries to identify and model explicitly the events that cause communication link failures.... more
This paper presents a new model to study the reliability of communication networks in which link failures are statistically dependent. The approach tries to identify and model explicitly the events that cause communication link failures. No conditional probabilities are needed, and so two major difficulties inherent to them, namely, an exponential number of conditional probabilities to deal with and a
Research Interests: Computer Science, Computational Complexity, Graph Theory, Network Analysis, Reliability Theory, and 12 moreReliability Engineering, Failure Analysis, Computation, Reliability Analysis, Network Reliability, Conditional probability, Reliability Modeling, Community Networks, Boolean Satisfiability, Electrical And Electronic Engineering, link failure, and Probability Distribution Function
Research Interests: Computer Science, Real Time Computing, Packet Switching, Computer Network, Protocols, and 14 moreQoS, Quality of Service, Interactive Video, Degradation, Smoothing, Call Admission Control, Video on Demand, Bandwidth, Admission Control, User Interaction, Electrical And Electronic Engineering, Demand Systems, Distributed Environment, and Set Top Box
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Page 1. Wireless Networks 3 (1997) 205216 205 Location update optimization in personal communication systems Ahmed Abutaleb and Victor OK Li Communication Sciences Institute, Department of Electrical Engineering ...