Reliability is concerned with the system capability of survival. In the past forty years, custome... more Reliability is concerned with the system capability of survival. In the past forty years, customer expectations have been increasing in response to evolving new technologies. As part of these evolutions, they are demanding from their suppliers: products with higher quality, low initial cost, improved customer support and products that are easy and inexpensive to maintain. For a supplier to survive, succeed and be profitable in todays market, It must do the following: a) Constant improvement in the quality of the products. b) Minimization of the cost. c) Be flexible and responsive to the customers requirement. This deals with reliability evaluation of combined generation and transmission system known as composite system. It describes a technique calculate composite system reliability with aging failure. The reliability evaluation deals with the a) Calculation of aging failure rate & aging repair rate of all Components of the system. b) Calculation of EENS value of all Components of t...
Traditionally the transmission gear-shifting schedule is based upon throttle position and vehicle... more Traditionally the transmission gear-shifting schedule is based upon throttle position and vehicle (or engine) speed. This paper proposes to add the third parameter, called terrain coefficient, to form a three-parameter gear-shifting schedule for improving vehicle fuel economy. The terrain coefficient is a compound parameter of the road grade and rolling resistance coefficient. It can be estimated in real-time by the proposed multi-step recursive Least Squares method. The Dynamic Programming and moving Least Squares are adopted to optimize the gear sequences and generate the three-parameter gear-shifting schedule. The proposed gear-shifting schedule is evaluated against the traditional two-parameter gear-shifting schedule via Simulink simulations and on-road experiments for a heavy-duty vehicle. The simulation results under the UDDS and US06 driving cycles show that the fuel economy of the proposed gear-shifting schedule is improved by 3.3% and 2.7% over that of the traditional two-p...
AbstractWe propose a scheme for transmission of variable bit rate (VBR) compressed video for int... more AbstractWe propose a scheme for transmission of variable bit rate (VBR) compressed video for interactive applications using the explicit-rate congestion-control mechanisms proposed for the available bit rate (ABR) service in asynchronous transfer mode networks. ...
Proceedings of MILCOM '96 IEEE Military Communications Conference, 1996
Supporting data applications over networks comprising both wireless and wireline links is of incr... more Supporting data applications over networks comprising both wireless and wireline links is of increasing importance for both military and commercial systems. Many standard data applications on current wireline networks are based on TCP/IP, the end-to-end flow and congestion control protocol widely used on the Internet, so that it is of crucial importance to devise network level controls that enable TCP
End-to-end data transport protocols have two main functions: error recovery and congestion contro... more End-to-end data transport protocols have two main functions: error recovery and congestion control. The information required by the sender to perform these functions is provided by acknowledgements (ACKs) from the receiver. The Internet transport protocol, TCP/IP, uses cumulative acknowledgements (CACKs), which provide a robust but minimal mechanism for error recovery which is inadequate for heterogeneous networks with random loss. Furthermore, TCP's congestion control mechanism is based on counting ACKs, and is therefore vulnerable to loss of ACKs on the reverse path, particularly when the latter may be slower than the forward path, as in asymmetric networks. The contributions of this paper are as follows:(a) We show that a simple enhancement of CACK provides sufficient information for end-to-end . We term this ACK format total ACKs (TACKs).(b) We devise a novel ACK format that uses TACKs for congestion control, and negative ACKs (NACKs) for efficient error recovery. Typically...
IEEE International Conference on Communications, 1993
The viability of distributed control restoration using digital cross-connect systems (DCSs) depen... more The viability of distributed control restoration using digital cross-connect systems (DCSs) depends on its capability for restoring services within specified time requirements. A Bellcore study of the impact of the DCS architecture on distributed restoration is reported. It is concluded that currently proposed distributed control DCS self-healing schemes may not meet the two-second restoration objective, regardless of the distributed algorithm,
IEEE INFOCOM 2003. Twenty-second Annual Joint Conference of the IEEE Computer and Communications Societies (IEEE Cat. No.03CH37428), 2003
We present a new algorithm for routing of messages in ad-hoc networks where the nodes are energy-... more We present a new algorithm for routing of messages in ad-hoc networks where the nodes are energy-constrained. The routing objective is to maximize the total number of messages that can be successfully sent over the network without knowing any information regarding future message arrivals or message generation rates. From a theoretical perspective, we show that if admission control of messages is permitted, then the worst-case performance of our algorithm is within a factor of O(log(network size)) of the best achievable solution. In other words, our algorithm achieves a logarithmic competitive ratio. Our approach provides sound theoretical backing for several observations that have been made by previous researchers. From a practical perspective, we show by extensive simulations that the performance of the algorithm is very good even in the absence of admission control (the admission control being necessary only to prove the competitive ratio result), and that it also performs better than previously proposed algorithms for other suggested metrics such as network lifetime maximization. Our algorithm uses a single shortest path computation, and is amenable to efficient implementation. We also evaluate by simulations the performance impact of inexact knowledge of residual battery energy, and the impact of energy drain due to dissemination of residual energy information.
Proceedings IEEE INFOCOM 2000. Conference on Computer Communications. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies (Cat. No.00CH37064), 2000
Page 1. Dynamic Routing of Bandwidth Guaranteed Tunnels with Restoration Murali Kodialam T. V. La... more Page 1. Dynamic Routing of Bandwidth Guaranteed Tunnels with Restoration Murali Kodialam T. V. Lakshman Bell Laboratories Lucent Technologies 101 Crawfords Comer Road Holmdel, NJ 07733, USA { muralik, lakshxn~i} @bell-labs.com ...
Proceedings IEEE INFOCOM 2006. 25TH IEEE International Conference on Computer Communications, 2006
The emergence of new applications on the Internet like voice-over-IP, peer-to-peer, and video-on-... more The emergence of new applications on the Internet like voice-over-IP, peer-to-peer, and video-on-demand has created highly dynamic and changing traffic patterns. In order to route such traffic with Quality-of-Service (QoS) guarantees without requiring detection of traffic changes in real-time or reconfiguring the network in response to it, we consider a routing and bandwidth allocation scheme that allows preconfiguration of the network such that all traffic patterns permissible within the network's natural ingress-egress capacity constraints can be handled in a capacity efficient manner. The scheme routes traffic in two phases.
I. INTRODUCTION Dynamic provisioning of bandwidth guaranteed paths with fast restoration capabili... more I. INTRODUCTION Dynamic provisioning of bandwidth guaranteed paths with fast restoration capability is an important network ... Link and Path Restoration A connection in a network can be protected at the path or link level. In link restoration (also often refered to as local ...
Proceedings IEEE INFOCOM 2006. 25TH IEEE International Conference on Computer Communications, 2006
Abstract Routing traffic subject to hose model constraints [5] has been of much recent research ... more Abstract Routing traffic subject to hose model constraints [5] has been of much recent research interest [10], [6]. Two-phase routing has been proposed [9], [18] as a mechanism for routing traffic in the hose model. It has desirable properties in being able to statically preconfigure the ...
Proceedings IEEE INFOCOM 2006. 25TH IEEE International Conference on Computer Communications, 2006
Traditional dynamic routing schemes in circuit- switched networks rely on accurate knowledge of t... more Traditional dynamic routing schemes in circuit- switched networks rely on accurate knowledge of the traffic ma- trix in determining algorithm parameters, etc. But the network traffic matrix is not constant, and so the schemes in general cannot make any guarantees on performance. On the other hand, Valiant load-balancing (VLB), which we study in this paper, uses the same parameters for
Reliability is concerned with the system capability of survival. In the past forty years, custome... more Reliability is concerned with the system capability of survival. In the past forty years, customer expectations have been increasing in response to evolving new technologies. As part of these evolutions, they are demanding from their suppliers: products with higher quality, low initial cost, improved customer support and products that are easy and inexpensive to maintain. For a supplier to survive, succeed and be profitable in todays market, It must do the following: a) Constant improvement in the quality of the products. b) Minimization of the cost. c) Be flexible and responsive to the customers requirement. This deals with reliability evaluation of combined generation and transmission system known as composite system. It describes a technique calculate composite system reliability with aging failure. The reliability evaluation deals with the a) Calculation of aging failure rate & aging repair rate of all Components of the system. b) Calculation of EENS value of all Components of t...
Traditionally the transmission gear-shifting schedule is based upon throttle position and vehicle... more Traditionally the transmission gear-shifting schedule is based upon throttle position and vehicle (or engine) speed. This paper proposes to add the third parameter, called terrain coefficient, to form a three-parameter gear-shifting schedule for improving vehicle fuel economy. The terrain coefficient is a compound parameter of the road grade and rolling resistance coefficient. It can be estimated in real-time by the proposed multi-step recursive Least Squares method. The Dynamic Programming and moving Least Squares are adopted to optimize the gear sequences and generate the three-parameter gear-shifting schedule. The proposed gear-shifting schedule is evaluated against the traditional two-parameter gear-shifting schedule via Simulink simulations and on-road experiments for a heavy-duty vehicle. The simulation results under the UDDS and US06 driving cycles show that the fuel economy of the proposed gear-shifting schedule is improved by 3.3% and 2.7% over that of the traditional two-p...
AbstractWe propose a scheme for transmission of variable bit rate (VBR) compressed video for int... more AbstractWe propose a scheme for transmission of variable bit rate (VBR) compressed video for interactive applications using the explicit-rate congestion-control mechanisms proposed for the available bit rate (ABR) service in asynchronous transfer mode networks. ...
Proceedings of MILCOM '96 IEEE Military Communications Conference, 1996
Supporting data applications over networks comprising both wireless and wireline links is of incr... more Supporting data applications over networks comprising both wireless and wireline links is of increasing importance for both military and commercial systems. Many standard data applications on current wireline networks are based on TCP/IP, the end-to-end flow and congestion control protocol widely used on the Internet, so that it is of crucial importance to devise network level controls that enable TCP
End-to-end data transport protocols have two main functions: error recovery and congestion contro... more End-to-end data transport protocols have two main functions: error recovery and congestion control. The information required by the sender to perform these functions is provided by acknowledgements (ACKs) from the receiver. The Internet transport protocol, TCP/IP, uses cumulative acknowledgements (CACKs), which provide a robust but minimal mechanism for error recovery which is inadequate for heterogeneous networks with random loss. Furthermore, TCP's congestion control mechanism is based on counting ACKs, and is therefore vulnerable to loss of ACKs on the reverse path, particularly when the latter may be slower than the forward path, as in asymmetric networks. The contributions of this paper are as follows:(a) We show that a simple enhancement of CACK provides sufficient information for end-to-end . We term this ACK format total ACKs (TACKs).(b) We devise a novel ACK format that uses TACKs for congestion control, and negative ACKs (NACKs) for efficient error recovery. Typically...
IEEE International Conference on Communications, 1993
The viability of distributed control restoration using digital cross-connect systems (DCSs) depen... more The viability of distributed control restoration using digital cross-connect systems (DCSs) depends on its capability for restoring services within specified time requirements. A Bellcore study of the impact of the DCS architecture on distributed restoration is reported. It is concluded that currently proposed distributed control DCS self-healing schemes may not meet the two-second restoration objective, regardless of the distributed algorithm,
IEEE INFOCOM 2003. Twenty-second Annual Joint Conference of the IEEE Computer and Communications Societies (IEEE Cat. No.03CH37428), 2003
We present a new algorithm for routing of messages in ad-hoc networks where the nodes are energy-... more We present a new algorithm for routing of messages in ad-hoc networks where the nodes are energy-constrained. The routing objective is to maximize the total number of messages that can be successfully sent over the network without knowing any information regarding future message arrivals or message generation rates. From a theoretical perspective, we show that if admission control of messages is permitted, then the worst-case performance of our algorithm is within a factor of O(log(network size)) of the best achievable solution. In other words, our algorithm achieves a logarithmic competitive ratio. Our approach provides sound theoretical backing for several observations that have been made by previous researchers. From a practical perspective, we show by extensive simulations that the performance of the algorithm is very good even in the absence of admission control (the admission control being necessary only to prove the competitive ratio result), and that it also performs better than previously proposed algorithms for other suggested metrics such as network lifetime maximization. Our algorithm uses a single shortest path computation, and is amenable to efficient implementation. We also evaluate by simulations the performance impact of inexact knowledge of residual battery energy, and the impact of energy drain due to dissemination of residual energy information.
Proceedings IEEE INFOCOM 2000. Conference on Computer Communications. Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies (Cat. No.00CH37064), 2000
Page 1. Dynamic Routing of Bandwidth Guaranteed Tunnels with Restoration Murali Kodialam T. V. La... more Page 1. Dynamic Routing of Bandwidth Guaranteed Tunnels with Restoration Murali Kodialam T. V. Lakshman Bell Laboratories Lucent Technologies 101 Crawfords Comer Road Holmdel, NJ 07733, USA { muralik, lakshxn~i} @bell-labs.com ...
Proceedings IEEE INFOCOM 2006. 25TH IEEE International Conference on Computer Communications, 2006
The emergence of new applications on the Internet like voice-over-IP, peer-to-peer, and video-on-... more The emergence of new applications on the Internet like voice-over-IP, peer-to-peer, and video-on-demand has created highly dynamic and changing traffic patterns. In order to route such traffic with Quality-of-Service (QoS) guarantees without requiring detection of traffic changes in real-time or reconfiguring the network in response to it, we consider a routing and bandwidth allocation scheme that allows preconfiguration of the network such that all traffic patterns permissible within the network's natural ingress-egress capacity constraints can be handled in a capacity efficient manner. The scheme routes traffic in two phases.
I. INTRODUCTION Dynamic provisioning of bandwidth guaranteed paths with fast restoration capabili... more I. INTRODUCTION Dynamic provisioning of bandwidth guaranteed paths with fast restoration capability is an important network ... Link and Path Restoration A connection in a network can be protected at the path or link level. In link restoration (also often refered to as local ...
Proceedings IEEE INFOCOM 2006. 25TH IEEE International Conference on Computer Communications, 2006
Abstract Routing traffic subject to hose model constraints [5] has been of much recent research ... more Abstract Routing traffic subject to hose model constraints [5] has been of much recent research interest [10], [6]. Two-phase routing has been proposed [9], [18] as a mechanism for routing traffic in the hose model. It has desirable properties in being able to statically preconfigure the ...
Proceedings IEEE INFOCOM 2006. 25TH IEEE International Conference on Computer Communications, 2006
Traditional dynamic routing schemes in circuit- switched networks rely on accurate knowledge of t... more Traditional dynamic routing schemes in circuit- switched networks rely on accurate knowledge of the traffic ma- trix in determining algorithm parameters, etc. But the network traffic matrix is not constant, and so the schemes in general cannot make any guarantees on performance. On the other hand, Valiant load-balancing (VLB), which we study in this paper, uses the same parameters for
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Papers by Tanay Lakshman